Compiled Biological Invasions

Module 1

The Importance of Invasive Species to Florida’s Natural Areas

Invasion Terminologies

• Alien species - A species not native to the area under consideration. Synonymous with “exotic”, “non-native”, and “introduced”
• Adventive species - A species that has arrived in a new locality but is not yet established there
• Established species - A species that has arrived in a new locality and has one or several reproducing, self-sustaining populations in the new locality
• Executive Order 13112, signed by Bill Clinton in 1992, defined invasive species
  • An alien species whose introduction does or is likely to cause harm to the economy, environment, or human health
• Not all introduced/exotic species are invasive
• Executive Order 13112
  • Established National Invasive Species Council. Currently 13 departments and agencies involved
  • Purpose: To prevent the introduction of invasive species and provide for their control, and to minimize the economic, ecological, and human health impacts that invasive species cause
  • The council wrote the National Invasive Species Management Plan
• Invasive has been used to describe a species that presents at least one of the following characteristics
  • Inhabits an area outside of its current or historical range of distribution
  • Reaches high abundances and dominates space
  • Competes with native species for limited resources
  • Has “recently” or is currently increasing its range size
  • Causes or is likely to cause harm to human health, econoics, or the environment

Stages in Invasion

• Transport
  • Species needs to be transported beyond the boundaries of its native range
    • Florida examples include Burmese Pythons (pet trade), Asian green mussels (travelling on the outside of ships)
• Introduction
  • Can be intentional or accidental
    • Intentional: On purpose
      • Live bait releases
      • Discarded plants in aquated or terrestrial areas
    • Accidental
      • Horiculture
      • Pet trade
      • Agriculture
• Establishment
  • Repeated reproduction and survival of individuals
    • Depends on biotic, abiotic factors
      • Brazilian Peppertree
    • Relies on characteristics of non-native species
      • Argentine black and white tegu
• Spread
  • Range or area occupied increases
    • Depends on species reproductive success, localized dispersal of offspring or propagules, and long-distance aided by humans
    • Species with high reproductive rates have an advantage
    • Species with efficient natural dispersal mechanisms can spread further
• Impact
  • Negative
    • Ecological
      • Fire regimes, changes in watershed and nutrient cycling, reductions in biodiversity, increased soil erosion
      • Melaleuca fire in Everglades National Park
    • Economic
      • Costs to control invasive species, lost yield of crops, lost revenue in recreational activities
    • Human Health
      • Mild allergies, spreading diseases
      • Diseases from Asian Tiger Mosquito

Pathways of Entry

• Natural invasion - Plant seeds, animal larvae, eggs or microorganisms carried by air, wind, water, insects or birds
• Intentional introduction - Countries introduce the alien species to promote agriculture, forestry and fishery, but they finally invaded local environments due to poor management
• Unintentional introduction - The most frequent invasion route, usually caused by international travelers or parcels

Why is Florida being Invaded?

• Florida pathways
  • Fish farms and nurseries
  • Pet trade
  • Tourists
  • Ballast water
  • Culturla introductions
• Factors that make Florida more likely to be invaded
  • Florida’s unique geography, tropical climate, insularity, and extensive aquatic habitats
  • The destruction or disturbance of native habitats for the creation of novel habitats
• Examples of invasive species
  • Redbay Ambrosia Beetle
  • Burmese Python
  • Hydrilla
  • Asian Clams
  • Nutria
  • Channeled Apple Snail

Impact of Invasive Species

• Recent estimates show invasive species cost the US nearly 120 billion annually
• Magnitude of threat of invasive species in Florida is of critical concern
  • South Florida’s habitats are prone to the establishment of non-native aquatic plants
  • Florida is dominated by novel habitats created by human disturbance

Non-Native Species in the World

Introduction

• Global perspective of the world’s biota
  • Less than 0.01% of known plants feed about 90% of world population
  • Only 8 domesticated animals provide most of our meat, milk, eggs
  • Many invasive species result from increased human mobility
• Inpact of invasive species is second only to human-induced habitat destruction
• In the US, invasive species responsible for about 40% of threatened and endangered species, leading to loss of biodiversity
  • Competition/Displacement of native species
  • Predation
  • Hybridization
• Clarles Elton - Father of invasive species awareness
  • The Ecology of Invasions by Animals and Plants - Published in 1948
  • First to investigate problem worldwide
  • Difficulty in controlling invasive species

Australia

• Relative isolation - NOT protecting from isolation
• Plants
  • # introduced plants = # native plants
  • Weeds hurt crop systems, pastures, horticulture
  • Costs AU$150
• Australia initial starting place for discipline of biological control of weeds
  • In 1920s, prickly pear covered thousands of acres of rangeland, displacing native species
  • Australia used cactus moth, which feeds on prickly pear pads
  • Within a few years, threat of invasion of prickly pear diminished
• Cactus moth worked in Australia because they only had a few invasive cacti species
• Cactus moth threatens native populations of Opuntia in Florida, the Southwestern US, and Mexico
• Vertebrates
  • Invasive species are about 40% of established species
  • Cost about AU$48 billion
• Invertebrates
  • Bees, wasps, ticks and flies cause human, livestock, and wildlife injuries and death
  • Mosquitoes transmit diseases
  • Mites and wood wasps damage crops and forests

Brazil

• Vertebrates
  • Only 2% invasive, impacts substantial
  • Fish and mammals
    • Rats
    • Cats
    • Pigs
    • Amphibians
    • Reptiles
    • Birds

British Isles

• Invasive species have cost UK economy between USD $6.9 and $17.6 billion since 1976
  • Vertebrates have cost about 4.7 billion
  • Plants have cost about 1.3 billion
  • Fungi have cost about 206.7 million
• Plants
  • Alien species outnumber native species
  • About 24% of established species cost crop systems
• Vertebrates
  • Alien vertebrates harm native organisms and environment
  • Importance: Mammals most important, followed by birds, fish, reptiles and amphibians
  • E.g. US grey squirrel displacing red squirrel

Europe

• Vertebrates
  • About 33% of non-native species cause economic, biodiversity, human health impacts
  • Canada geese
• Arthropods
  • Non-native insects equal about 94%
  • Introduced from ornamental plants
  • Human disturbed environment
  • 14% negatively impact environment
• Plant pathogens
  • Non-native fungi - Most important group
    • 77% plant pathogens
  • Most damaging pathogens attack grapes and potatoes
    • Grape industry: American downy and powdery mildews
    • Social impact of potato late blight in Ireland
      • Potatoes have low genetic diversity (clonal), meaning blight was super bad

India

• Plants
  • Invasive species threaten native ecosystems
  • Alter plant composition, reduce biodiversity, change soil structure, affect public health
  • Despite these problems, growing Jatropha curcas for biofuel
  • Jatropha curcas are poisonous and potentially invasive
• Invertebrates
  • Major impacts on crop production
    • Mites attack coconuts
    • Mealy bugs attack cotton and papaya
    • Golden apple snail attacks rice
  • Golden apple snail threatens public health because they are an intermediate host for human parasitic nematode

New Zealand

• Plants
  • Approximately equal number of native and non-native species
• Vertebrates
  • Ecological catastrophe following human arrival in New Zealand
    • Maori settlers introduced dogs and cats
    • Approximately 60 native bird species are extinct
  • European settlers added over 90 alien species
    • Cattle and sheep beneficial to New Zealand’s economy

United States

• In the United States, approximately 50,000 plants, animals, and microbes considered adventive during the last century
• Plants
  • Many exotic plants in Port of Miami and Jacksonville
  • Weeds of agricultural or horticultural significance
    • Cogongrass
    • Melaleuca
  • Cost about 34 billion dollars annually
  • Impacts
    • Direct: Displacing native plants
    • Indirect: Reduce fauna associated with natives
  • Most damage in Southern and Western US
• Vertebrates
  • Cost about 47 billion annually
  • Rodents, cats, feral hogs, pigeons, starlings, Burmese python, coqui frog, European carp, Asian carp
• Invertebrates
  • Cost about 15 billion annually
  • Florida gets one potentially invasive insect per month
• Pathogens
  • Citrus canker and laurel wilt
  • Mosquito-transmitted diseases

Summary

• 120k non-native organisms in 7 countries
• Invasive species and disease spread
• Alien species invasions are an ongoing problem
• Globalization of people and products

Module 2

Impacts of Alien Plants in Australia

Introduction

• Number of alien plant species unknown
  • Estimated at 27k
  • 10% to 15% naturalized
• Regional variation in alien plant species
  • Offshore islands especially vulnerable, over 50% have become invaded
  • Consistent with island biogeography theory
• Number of naturalized alien plant species increasing
  • About 5 species per year

Impacts on Agricultural Systems

• Crops and pastures
  • Crop species mostly alien
  • Pasture grass species in South Australia also alien
    • Origin - Mediterranean Europe
• Some pasture species negatively impact crops
  • Example is clover, Trifolium subterraneum
• Economic aspects - Presence of alien plant species entails control costs (Bottom is prevention/benign, top is intervention/toxic)
  • Cultural - Resowing pastures
  • Mechanical - Cultivation of crop lands
  • Biological - Host specific natural enemies
  • Chemical - Spraying of herbicides
  • Various combinations: Integrated Pest Management (IPM)
  • Alien plant species lower crop and pasture yields
    • Contaminate agricultural products
    • Negatively impact livestock
      • Direct: Poisoning
      • Indirect: Poor performance
      • Negatives outweigh positives
• All aspects lead to revenue losses
  • Crop examples: Wild oats, Skeleton weed, Mexican feather grass, Spanish thistle
  • Pasture examples: Serrated tussock, Paterson’s curse/Salvation jane, Blackberry
• Some people say invasive plants are good
  • Invasive plants can create conflicts of interest
    • Cattle owners don’t want Salvation Jane controlled
    • Resolving conflicts of interest led to the Biological Control Act

Biodiversity Impacts

• Complex, variable, often highly subjective
• Alien plant species may impact both agro- and natural systems
• Effects can be positive, negative, or neutral
  • Catclaw mimosa
  • Athel tree (Tamarix)
• Alien plant species may provide food and refuge for other alien organisms
• Complex, variable, often highly subjective
• 1, 2 bad, 3 good, 4 neutral
• Typically, cost-effectiveness of control programs assessed
  • Bitou Bush: Cost.benefit is 20:1
  • Strategic use of chemica, mechanical, biological, and cultural control
• Need to make every effort early to remove invasive plants

Case Study

• Prickly Pear Cactus
  • Example of positive outcome from introduction of a plant brought in for biological control
  • Prickly pear cactus in Australia started discipline of biological weed control
• 1700s, prickly pear cactus introduced for red dye from Brazil
• Early 1900s, prickly pear invaded
• 1925 cactus eating moth introduced, helped a ton

Positive

• St John’s Wort: Antidepressant, first plant targeted for classical biological control in the US
• Paterson’s Curse: High in omega-3 acids

Negative

• Parthenium weed: Causes contact dermatitis, especially in men
• Paterson’s Curse: Causes skin irritation, allergic rhinitis (hay fever)
• Peruvian peppertree: Causes allergic bronchitis (asthma)
• Brazilian peppertree: Causes skin irritation, allergic rhinitis (hay fever)
• Thorn apples, Hemlock: Death from eating
  • When an animal ingests these, it can become sick, have reproductive problems, or die
    • Acute effects: Animal drops to ground almost immediately after ingesting
    • Chronic effects: Animal experiences poor performance
• Subterranean Clover: Estrogens cause abortions and infertility in sheep
• Phalaris: Alkaloids cause staggers or death
• Ryegrasses: Alkaloids cause staggers or death
• Sylibum thistle: Nitrate ions cause blood poisoning
• St. John’s Wort: Hypericin causes photosentisization and poor condition in sheep
• Paterson’s Curse: Alkaloids interfere with liver function
• Brassicaceae: Contains cyanogenic compounds
• Oxalidaceae: Produce highly toxic oxalates
• Polygonaceae: Produce highly toxic oxalates

Environmental and Econoomic Costs of Invertibrate Invasions in Australia

Introduction

• Big numbers of devastating adventive invertebrates in Australia
  • Transportation of goods
  • Human and animal migration
  • Weather patterns
• Invertebrate invaders began with human colonization in the 1780s
  • Ships bringing people brought mosquitoes, lice, stored food insects
• Today, globalization worsens the problem
  • Shorter travel times increase vector survival
  • Despite barriers, humans contribute to homogenizing the world’s biota
• Annual costs estimated at 5 to 8 billion dollars

Invasive Arthropods

Aedes Mosquitoes

• Vectors of dengue, yellow fever, Aika, Chikungunya
• Economic impacts
  • Medical and vector control costs
  • Worker absence
  • Lost tourism
    • A. aegypti - Annually 2-17 million dollars
• Dengue unlikely to become endemic
  • Lack of reservoir hosts
  • Outbreaks are importations of the virus by tourists or returning residents
• Cost estimation
  • Pre 1990, cost of work lost to Dengue outbreaks: 2 billion in US
  • Annual total cost for above species in US is 17 million a year since 1990
  • Since 2000, increased Dengue outbreaks thanks to airport construction in Cairns
  • Difficult to justify that Dengue is not endemic in Australia
  • Government recommendation - Collect rainwater in containers will like increase the problem

Culex Gelidus Mosquitoes

• Breeds near livestock pens for high nutrient loads
• Vector of Japanese Encephalitis and other flaviviruses in the Northern Territory
  • Symptoms: Headache, fever, convulsions, and in serious cases, coma and death
  • Hospitalization: 14 days
  • Mortality rate: 50%
  • About 40% of survivors have permanent mental or physical problems
  • Requires chronic care
  • Vaccine: 95% effective
  • Horses and pigs also infected

Apis Mellifera

• Introduced in 1822
• Commercial honey production
• Bee (and wasp) stings are second leading cause of death from venomous organisms in Australia
  • Hospitals code wasp and bee stings together
  • US 10 million dollars in annual hospital expedentures
• Economic impact - Overwhelmingly positive

Vespula Germanica

• Exotic wasps inflict damage with no benefit
• Introduced in 1954
  • Established in Tasmania in 1959
  • Established in mainland Australia in 1977
  • National Control Strategy implemented from 1997-1998
• Increased costs for horticulture, healthcare, tourism, and nest destruction
• No human fatalities directly attributable to this species
• Social wasps as invaders
  • Queens seek refuge in transported goods
  • Globaliztation of trade
  • Production of 1000s of workers following single mating
  • Short generation time and high reproductive rate
  • High dispersal capacity
  • Survival in range of habitats and climates
  • Lack of natural enemies
  • Absence of competing queens during invasion process

Solenopsis Fire Ants

• The effects of S. geminata are limited to northern territories
• S. invicta was discovered in the southern Queensland in 2001
  • Suspected origin is US or South America
  • Both single and multiple queen colonies are present
• US experience is cause for concern for Australia
  • Resistance to natural and chemical controls
  • Ecological, agricultural, health problems
    • Ecological - Sea turtles and bobwhite quails
    • Health - Sting over 50% of endemic human population annually
  • Production and control costs in US about 250 million sollars
  • USDA bio-based area-wide control program
    • Decapitating fly

Boophilus Microplus

• Most costly invasive arthropod (134 million dollars)
• Introduced in 2972 from Batavia (Jakarta)
• Distribution determined by low temperature and relative humidity
• Not established in Victoria, Tasmania, and the South
• Calves are weakened and can die from loss of blood
• Vector of protozoan parasites and bacterium
• Impacts
  • Direct
    • Loss of condition, anemia, death, damaged hides
    • Loss of milk production, calves
  • Control costs
    • Stock handling, acaricides, toxicity, quarantine
  • Indirect (Tick-borne diseases)
    • Vaccines, treatment, and handling costs

Old World Screwworm Fly

• As of 2011, this was restricted to Papua New Guinea, only 3 km from Australia
  • It is capable of dispersing approximately 11 km
  • Intercepted on boats in Darwin Harbor
• Obligate parasites of mammals
  • Cause cutaneous myiasis
  • Cuases wounds to contain numerous larvae, injuring the host
• Direct effects
  • Damaged hides and muscle
  • Declines in production
  • Death of animals
  • Treatment costs
• Changes in livestock production practices
  • Sterile insect technique
    • Sterile males can’t mate to make larvae
    • Technology already developed
    • Large numbers of flies needed

Papaya Fruit Fly

• First detected in 1995
• Attackes wide variety of fruit and vegetables
• Presence resulted in trade bans
• Successful eradication program in 1996
• Surveillance and toxic bait

Citrus Canker

• Causative agent bacterium
  • Xanthomonas axonopodis (Hasse)
• Native to Asia on citrus and its relatives
  • Spread to New World, Middle East, and Pacific region
• Affects oranges, grapefruit, limes, etc.
• Unsightly fruit edible but unsalable
• Symptoms include lesions on stems, leaves, and fruits, premature leaf drop, and loss of plant vigor
• Dispersal via infected plant material, wind, contaminated equipment
• First detected in Northern Territory in the 1900s
  • New outbreak in 2004
  • Central Queensland - 3 orchards
  • Eradication in February 2009
• Response program implemented
  • Removal of commercial and non-commercial citrus and native hosts
  • Restructions on replanting and introduction of potential hosts
  • Intensive surveillance program
• Since 2005, costs for responses to exotic pests causes government and private sector programs

Banana Skipper

• Cause production losses (about 70 million dollars)
• Biological control program implemented in Papua New Guinea (about 700K dollars)
• Successful biocontrol program could reduce losses to 3 million dollars annually
• Example of a “Short Route” biocontrol program
  • Transferring a successful program to a new area
  • Reduced costs because research and development already done

European House Borer

• Destructive timber pest
• First detected in Perth in 2004
• National Control Campaign implemented in 2007

Honey and Leafcutter Bees

• Honeybee beneficial
• Benefits of honeybees in Australia
  • Beekeeping industry makes 60-65 million dollars annually
    • Production of honey, wax, queen bees
  • Crop and plant pollination
    • Apples, cotton, citrus, onions, mangoes
    • Approximately 1.2 billion dollars generated
• Nitrogen enrichment of soil by bee-pollinated pasture legumes (about 1.9 billion dollars)
• Benefits not without costs if parasite invades
  • Varroa mite
  • Can destroy entire bee colonies

Marine Invaders

• International shipping
• Discharge of ballast water
• Attaching to vessel hulls
• Importation for aquarium trade
• Deliberate introduction
• Transport fishing equipment
• 1995 - National Introduced Marine Species Port Survey program made
• 170 exotic species discovered

Black Striped Mussels

• First detected in Darwin marinas in 1999
• First recorded marine pest
• Closely related to zebra mussels in US
• In Australia, predicted to invade oyster farms, marine pumping facilities, recreational/inshore vessels, all port facilities
• Potential environmental and economic impact could be substantial

Northern Pacific Sea Star

• 1986 - First discovered near Hobart, Australia
• Predator of shellfish, consumes any animal tissue
• Tremendous reproductive potential
  • 1998 - 50 specimen in Port Philip Bay
  • 1999 - Increased to 12 million in 1 year
• In 1999, pollution of Derwent Estuary led to high sea star population
• Recognized worldwide as a significant pest of aquaculture, commercial, recreational fisheries
• Threat to matine environment

European Fan Worm

• 1965 - First discovered in western Australia in Ballast water suspected vector
• Dominant species in Port Philip Bay
• Threat to scallop beds
  • Efficient phytoplankton filter feeder
  • Allows seagrass beds to overgrow
• Intense food competition detrimental to native shellfish
• 1998 - International Maritime Organization (IMO) made international framework for ballast water management
• 2002 - National system for prevention and management of marine pest incursions adopted

New Zealand Screw Shell

• Inadvertently introduced into southeastern Tasmania in 1920s
• Colonized more territory in Australia than any other exotic or benthic pest because it tolerates a wide range of temperatures and depths
• Has a hard shell that makes it immune to predation
• Because it is so prolific, native scallops and screw shells are at risk of displacement
• Live and dead shells can cover the sea floor to depths of 80 meters
• Dead shells are detrimental to other seafloor-inhabiting animals

Module 3

Non-Indegineous Vertebrates in Australia

Introduction

• Large land masses less susceptible to invasion
  • Australia exception
• Since 1800s, vertebrates imported for food, clothing, pest control, pets
  • Rats and mice adventive
• About 80 species of exotic vertebrates established, over 30 considered pests
• Short-term economic impacts
  • Losses to agriculture about 420 million dollars
  • Control and R and D about 80 million dollars
  • Environmental impacts, loss of biodiversity
• Attributes of adventive vertebrates
  • Good climate match
  • History of establishment outside Australia
  • High reproductive rate
  • Generalist diet
  • Ability to thrive in disturbed habitats
• Law mandates pest control
  • Private landowners and agriculture pests
  • Government agencies are responsible for native species and communities
• Direct impacts on livestock
  • Predation
  • Pasture competition and rainfall dependent
  • Permanent degradation of soil and pastures
• Indirect impacts
  • Reservoirs and vectors of diseases affecting native wildlife, domestic animals and humans
  • Hosts for new diseases entering Australia
    • Rabies in wild canines
    • Foot and mouth disease in feral hogs and goats
    • Strategies for prevention costly
• Enviornmental costs difficult to quantify
  • Changes in vegetation cover and composition
  • Changes in soil - inhabiting arthropod fauna
  • Changes in soil structure
  • Hybridization with native species
• Exotic vertebrates are valuable resource
  • Hunting, fishing
  • Feral animals harvested for meat and hides
  • 10 to 30 million dollars per year export industry
  • Rabbits and cats are food source for aborigines
  • Trout and carp harvested for consumption, pet food, fertilizer

Damage and Control Costs

• Estimates for annual expenditures based on several assumptions
  • Average landowner spends 250 dollars per year
  • Not all farms have problems
  • Pest damage and control activity vary yearly
  • Economic and social factors may preclude any pest control
  • Some pest control actions expensive initially with low maintenance costs
    • Examples: Exclusion fences and nets
  • Reported control and research cost estimates conservative

Rabbit

• Introduced by Europreans for food, fur, skins
• Most widespread and significant pest
• Scale of impact unprecedented until RHD
• Impacts
  • Reduced carrying capacity, wool production, weight gain, increased mortality
  • Pasture degradation, crop damage
  • Threaten native plants, shrubs and trees
  • Competition with native birds and animals (direct)
  • Maintain high predator populations (indirect)

Fox

• Impacts
  • Lamb predation (7-30%)
  • Calf, goat kit, and poultry losses
  • Prey on native wildlife, especially threatened and endangered species
  • Limiting factor for successful endangered mammal reintroductions
  • Loss in ecotourism from decline in native animals in wildlife parks

Feral Goat

• Impacts
  • Overgrazing alters long-term composition of perennial vegetation
  • Interbreed with valuable domestic goats
  • Interfere with seedling tree production
  • Damage fences
  • Contaminate water bodies
  • Reservoir for exotic livestock diseases
  • Compete with native fauna via resource competition
  • Alter ecosystem function

Feral Pig

• Impacts
  • Lamb predation (19-32%)
  • Root up quality pasture for livestock
  • Damage water control structures
  • Contaminate ponds and waterholes
  • Destroy fences
  • Reduce crop yields
  • Native habitat degradation
  • Predation on native animals
  • Harbor and spread plant and animal disease

Wild Dog

• Impacts
  • Livestock predation
  • Determine sheep and cattle distribution
  • Kill more sheep than they can eat
  • Affect native fauna populations
  • Hybridization threatens survival of Dingoes
  • Attacks on humans, especially Dingoes
  • Outbreaks of diseases linked to wild dogs
    • Hydatidosis - Parasite fatal to humans
    • Potential vectors of rabies bacterium

Feral Cats

• Impacts
  • Cause major decrease in small vertebrate population
  • Reservoir host for several diseases
    • Carnivore tapeworm, Toxoplasmosis (native species)
    • Scarcosporidiosis (sheep)
  • Major problem on Florida Keys
    • Threat to endangered rodent populations

Feral Donkeys and Horses

• Impacts
  • Compete with livestock for water and pasture
  • Habitat destruction and contribute to erosion
  • Destroy fences
  • Contaminate watering holes
  • Potential for spreading diseases

Feral Buffalo and Camel

• Impacts
  • Harbor and spread livestock diseaseses
    • Brucellosis and Tuberculosis
  • Damage freshwater swamps
    • Trails cause saltwater intrusion, which kill Melaleuca forests
  • Trample nesting sites of rare turtle
  • Grazing reduces shelter for small desert mammals
  • Damage fences

Black Rat

• Impacts
  • Destroy 30% of Macademia nut crop
  • Damage citrus, avocado, and banana crops
  • Indirectly influence owl populations via use of anti-coagulant rodenticides
  • Prey on native birds, reptiles inhabiting offshore islands
  • Compete with island inhabiting small mammals

Cane Toad

• Impacts
  • Consumes native arthropods, affecting invertebrate communities
  • Prey on and compete with native amphibians
  • Anectodal evidence toxins poison native predators
    • Examples include native cat and lizard

Starling and Sparrow

• Impacts
  • Damage fruit and grain crops (about 10%)
  • Consume and spoil grain in cattle, pig and poultry feedlots
  • Potential to spread salmonella and tuberculosis
  • Nesting in buildings leads to fire hazards, parasites, and cosmetic damage

Myna, Blackbird and Mallard

• Impacts
  • Compete with native birds for nesting sites
  • Pests of fruit crops
  • Nesting in buildings causes fire hazards, parasites, and cosmetic damage
  • Harbor parasites
  • Disperse seeds of invasive weeds (Lantana)
  • Hybridize with native species like Mallard and Pacific Black Duck

European Carp

• Impacts
  • Increase nutrient, algae, and suspended sediment concentrations
  • Reduce water quality, increase pump wear
  • May make aquatic habitats less suitable for other fish
  • No evidence of native fish declines
  • Few recreational anglers target carp
  • May cease fishing activities in some areas

Trout, Mosquitofish, and Tilapia

• Impacts
  • Adversely affect native fish via predation, competition for food and habitat
    • Trout displace some native species
  • Reduce invertebrate and amphibian populations
    • Especially mosquitofish
  • Plant removal by Tilapia reduces habitat quality

Summary

• Overall costs about 500 million dollars
• Safer BioTech controls on the horizon
  • Viral vectored immunocontraception

Economic Impacts of Weeds in New Zealand

Introduction

• New Zealand is one of the most invaded areas
• About 500 adventive plant species threaten agricultural industries or biodiversity
  • One speices/month over past 150 years
• Brief overview for New Zealand
  • Total costs of weeds to economy
  • Cost of weed management on public lands
  • Economic costs of example weed species

National Total

• Two components proposed by Bertram
  • Defensive Expidenture (DE): Costs for prevention and control
  • Loss of Economic Output (LEO): Annual production losses due to current infestations
  • Total cost = Defensive Expidenture (DE) + Loss of Economic Output (LEO)
• 1980s - Development of Biosecurity Act
  • Adopted 1993, defined role of governments
  • Total DE for all pests - 419 million New Zealand dollars
    • DE for weeds - About 276 million New Zealand dollars (65%)
  • Total LEO for all pests - 1.3 billion New Zealand dollars
    • LEO for weeds - 302 million New Zealand dollars (24%)
  • National total for weeds in New Zealand
    • 578 million New Zealand dollars annually

Public Conservation Land

• Natural areas about 30% of land
  • 17% threatened by weed invasions
  • Weeds constitute risk to 49% of native species
• Department of Conservation (DOC) charged with weed management
  • All costs in DE category only
  • Excludes value of biodiversity loss
  • Estimated at 4.42 billion New Zealand dollars
• Analysis of 58 weed control projects
  • Light infestations - NZ$11/ha
  • Moderate - NZ$11-225/ha
  • Dense - NA$1150-2800/ha
• Exponential increases occur in 5-8 years

Gorse

• Arrived with umans in early 19th century
• Spiny (deters grazing), persistent seed bank, and fire adapted
• Major weed problem for about 100 years
  • Impacts survival of threatened and endangered species
• Major weed of pine plantations
  • High DE for site preparation and over-sowing with “introduced” grases and legumes for Gorse suppression
• DE and LEO costs - NZ$14.7 million + NA$23.3 million = Total NA$38 million

Scotch Broom

• 2nd most important woody weed
• Candidate for classical biological control
  • Introduced beetle Gonioctena olivacea
• On-farm benefits from biocontrol
  • NA$1.8 million (DE) + NZ$4.8 million (LEO) = NZ$6.6 million
• Impact on forestry - 1.5 million
  • Costs for both Gorse and Broom additive despite similar ecologies and control programs
• Impacts conservation lands
  • Across all sectors, NZ$5.3 million for control (DE) annually

Old Man’s Beard

• Destructive vine of forests
• Damages revegetation plantings and potential problem for pine plantations
• Biocontrol program costs 1-2 million dollars over 6 years
• DOC DE - 4.3 million/year
• Would biocontrol be a better investment than the current defensive expenditures?
• Calculated contingency valuation: The willingness to fund research for expected benefits
• Results of postal survey - 50-124 million dollars
• Amount projected by survey contrasted sharply with amount spent
• Take home message is New Zealanders value their native forests and biodiversity

Thistles

• Bull thistle, Cirsium vulgare
• Major problem for agriculture, especially improved pastures
• Seeds are transported in shipments of hay
• Estimated DE + LEO = NZ$13 million

Giant Buttercup

• Important weed of dairy pastures
• Dairy products represent significant part of New Zealand’s export economy
• LEO - NZ$145 million in 2002
• Resistant to herbicides
• Fungus developed as bioherbicide

Alternate Funding

• Alternatives to general taxation include extensive weed control efforts on conservation lands
  • Taxation
  • Volunteer labor; DOC covers travel expenses
  • Levy tax on horticulture producers
    • Kiwi fruit - New invader
    • Growers pay control costs before releasing new crop and ornamental plants, more likely to protect native biodiversity

Summary

• Total costs for DE is about NZ$276 million
• LEO for uncontrolled weeds about NZ$302 million
• Average cost/weed species is about NZ$1.5 million
  • Based on 200 weeds intensively controlled
• DOC spends NZ$20.3 million
  • 328 plants on 33% of New Zealand’s landscape
• Costs should be borne by growers of cultivated plants that later become invasive
• There are enormous costs for weeds in New Zealand when biodiversity losses are included
• Investment in biological research and implementation is paying off

Module 4

Alien Invertebrates in New Zealand

Introduction

• About 2200 alien invertebrate species established
• 90% of invertebrate pests are alien species
• Significance of problem resulted in new legislation
  • Biosecurity Act of 1993
  • Establishment of government post, which is Biosecurity Minister
• New Zealand’s definition of biosecurity
  • “Protection from risks posed by organisms to the economy, environment, and people’s health, through exclusion, eradication and control
• Vespit wasp and clover root weevil
  • Two most significant invaders since early 1970s

Ecolgical Impacts

• In general, few alien invertebrates have a significant effect on native biota
  • “...Absence of evidence is not evidence of absence…”
• Some exceptions
  • Introduced social wasps
  • Argentine ant
  • Hybridization of native and introduced blue butterflies
  • Parasitism of red admiral butterfly by ichneumon wasp
  • Certain biological control agents
• Direct economic losses (LEO) from 4 key invertebrate pests equal to NZ$195 million - NZ$380 million
• About 55% total losses from all pests
• Total DE is $242 million
• Specific examples
  • Successful biocontrol of Argentine stem weevil decreases losses to about $80 million
  • Clover root weevil is about $300 million
• Total cost for all alien invertebrate pests calculated to be about $880 million
• Livestock invertebrate parasites
  • Intestinal nematodes and sheep flystrike cause flesh-feeding fly maggot infestation
• DE ($145 million) + LEO ($1.2 billion) = $1.36 billion

Features of Invertebrates Incursions

• Numerous alien invertebrate pests, about 2 per year
  • Pastures - Clover root weevil, Argentine stem weevil, New Zealand grass grub, lucerne aphid, black beetle, lucerne flea beetle
  • Horicultural pests - Codline moth, European red mite, light-brown apple moth
• Succesful border interceptions
  • Asian gypsy moth and Mediterranean fruit fly
  • “Hitchhikers” not associated with commodities elude detection
• Certain pests caused < damage than expected due to climate limitations
  • Black beetle from South Africa, tropical grass webworm
  • Climate change could increase pest distributions

Examples

Argentine Ant

• Discovered in 1990
• Impacts in the U.S., Australia, and South Africa
  • Disrupts ecological/symbiotic relationships
  • Possible international trade bans
  • New Zealand government funding for national survey of ant distribution and control options

Mediterranean Fruit Fly

• Monitoring system using pheromone traps in place before pest intercepted
• Successfully eradicated in 1996 with insecticide-laced protein baits at DE $5.3 million

White-Spotted Tussock Moth

• Unexpected, since it’s not a pest in its native range
• Eradication program using Btk implemented to protect forests
• Cost of eradication is about $12 million

Painted Apple Moth

• Detected in 1999, native to Australia
• Wide host range impacts natural areas, forestry, and horticulture
• Localized spraying with insecticide; infested vegetation destroyed
• DE - $2.5 million
• Threat to native Kowhai tree
• Biosecurity lessons learned
  • No contingency funds for emergency response
  • Risk analysis needed for native flora and fauna
  • Communication among agencies needed
  • Role of public in discovering invaders

Mosquitoes

• Southern Salt Marsh Mosquito
  • Discovered in 1999
  • Vector of Ross River Virus
• Asian Tiger Mosquito
  • Vector of dengue fever
  • Eradicated

Varroa Mite

• Discovered in 2000
• Brood parasite of Asian hive bee
• Eradication rejected in favor of management plan

Case Study Incursions

• Lucerne pests like weevil and aphid
• Analysis focused on spread rather than local densities
• Two key features
  • Latent period typically exhibited by plants
  • Outbreak followed by decline are typical of animals, follows boom-and-bust pattern

Lucerne Root Weevil

• Discovered in 1974, came from Australia via Europe
• High initial density followed by decrease
  • Drought followed by classical biocontrol from parasitoid introduced in 1982
  • Decline in lucerne production

Blue-Green Aphid

• Similar pattern but reasons for decrease not clear
  • Density-dependent, decrease in host plant condition after 1st season
  • Effect of parasitoids (1977) minimal
  • Ditto generalist predators
  • Aphid-resistant lucerne varieties
  • Decline in lucerne abundance

Common Wasp

• Discovered 1983
• Probably arrived 19702
• Most widespread of 4 established species
• Displacing German wasp (introduced 1943)
• Success of social wasps as invaders
  • Queens are transportable goods
  • Globalization of trade
  • Production of 1000s of workers following single mating
  • Short generation time and high reproductive rate
  • High dispersal capacity
  • Survival in range of habitats and climates
  • Lack of natural enemies
  • Broad host range
  • Absence of competing queens during invasion process
• Invasion process and German wasp displacement
  • 1991 - German species widespread but common wasp generally more abundant
  • Co-exist generally, common wasps are better competitors
    • Beech forests support highest common wasp populations
    • Trees attacked by scale insects and produce honeydew
    • Niche partitioning means common wasps forages on plants, German wasp in forest litter
  • 1991 - German wasp species widespread but common wasp generally more abundant
  • Co-exist generally, common wasps are better competitors
    • Honeydew better source of protein, making higher queen quality
    • Common wasp renews honeydew more efficiently before fermentation
• Ecological impacts
  • Compete with native birds and invertebrates for food
    • Native bird species are Kaka, Tui, Bellbird
  • Population reduction of native invertebrates
    • Populations of native caterpillars and spiders at risk
  • Honeydew removal affects nutrient cycling and perhaps tree health
    • Reduction in carbon flow from honeydew to soil microorganisms
    • Microorganism composition altered at base of trees
• Wasp management response
  • Threat to conservation and ecotourism
  • Major wasp control effort
    • Protein-based poison bait effective if reinvasion occurs
    • Biocontrol attempted by introducing parasitoid is unsuccessful
    • Beauvaria fungus bait shows promise
    • GMO wasp gut bacteria increases pathogenicity
    • SIT approach under consideration to irradiate queens to make them infertile

Clover Root Weevil

• Discovered in 1996 but arrived in 1994
• Overlooked dur to similarity to lucerne weevil
• Discovered by accident and has different pheneology
  • Lucerne weevil is univoltine
  • Clover weevil is bivoltine
  • Explained higher population densities
• High densities from wet spring conditions
  • Greater damage and higher overwintering population
  • Implications for irrigation schedules
• Economic impact
  • Damage white clover because larvae feed on roots
  • Threat to clover pastures and seedling survival
  • N-fixation by roots increase protein levels
    • Implications for grazing industries, especially dairy
  • Clover replaced animal-based protein feed
    • Prevent mad cow disease
  • Economic cost of loss of clover N-fixation is NZ$300 million
• Management response
  • Develop management program with 3 components
    • Short-term cultural practices by farmers
    • Examine cultivation and fallow periods
    • Testing insecticide exclusion barriers are ineffective
    • Methods of clover re-establishment by over-drilling because weevils relish seedlings
    • Coating seeds with pesticides is ineffective
    • Clover-resisant varieties
      • 250 lines selected and evaluated for 3 years
      • Some indication of resistance or tolerance to weevil
    • Biological control is classical or pathogens
    • Lucerne weevil parasitoid tested, ineffective
      • Recent surveys in Europe show different lucerne weevil parasitoid ecotype, promising candidate
    • Pathogen research
      • Beauveria fungus, bacillus bacterium
      • Combine with aggregation pheromones for developing “Attract and infect” technology

Summary

• Need for better interception and monitoring programs
• Developing research and management programs is difficult
• Involving farmers early on garners support
• Recognition of importance of collaborative research with Europe
• Abundance of clover resource indicator of potential pest problems

Environmental and Economic Costs of Alien Vertebrates in New Zealand

Introduction

• Isolation is extreme flora and fauna endemism
  • Dominated by birds and reptiles
  • Except for birds, no native land mammals except for bats, which can fly
• Last habitable land mass for humans
• Polynesian settlers brought ecological disaster
  • Maori people brought dogs and rats
  • 35 bird species were hunted to extinction
  • Rats eliminated flightless insects and reptiles
• Later, Europeans introduced over 90 vertebrates
  • 32 mammals, 36 bids, 19 fish
  • Sheep and cattle beneficial

Ecological Costs

• About 9 native bird species now extinct
  • Predation by introduced mammals (rats, cats, stoats)
• Predation and competition by mammals threaten native reptiles and frogs
• Introduced salmon and rainbot negatively impacting native fish pops
  • Largely ignored popularity of fishing
  • Illegally introduced rudd and koi carp which are noxious and under management
• Possums, deer, and goats impacting flora
  • Selective browsing of native plants
• Rats, cats, and stoats are agents of faunal changes
  • Target vulnerable and slow-breeding animals by large invertebrates, ground feeding birds
  • Large flightles birds are especially vulnerable like the brown kiwi, New Zealand’s national bird
• IUCN Red List shows 69 of 287 birds (24%) threatened
  • Highest of any country
  • Surviving only on mammal-free islands
• Bertram’s approach - Review
  • DE (Cost of prevention and control)
  • LEO (Loss of economic output)
  • Welfare loss (New category)
    • Pest presence + impact on conservation lands
• Devensive expenditures (DE)
  • Prevention includes quarantine and border-control cost
  • Control includes research, pest control, and surveillance
  • New pest introductions rare
    • Investment in prevention (NZ$184 million)
    • Surveillance/Response (NZ$45 million)
    • Includes plant diseases, invertebrates, and vertebrates
• Large central government expenditure for controlling established vertebrate pests
  • Bushytail possums are vectors of bovine TB
  • Total cost for possum TB research for 2008 - 2009 - NZ$82 million
• Major programs include eradicating alien mammals from large islands - NZ$2.1 million
  • Campbell Island - Cattle, sheep, and rats
  • Raoul Island - Goats, rats
  • Kapiti Island - Possums, rats
  • Codfish Island - Possums, rats
  • Enderby Island - Rabbits and mice

Production Losses

Possums

• Losses to agriculture, forestry, and erosion control plantings - NZ$52 million
  • 5% loss of pine plantings - $282/ha
• Immense potential damage to economy from transmission of bovine tuberculosis
• Exports of produce, beef, and venison threatened from import restrictions of trading partners
• Dairy produce earns > $3 billion

Rabbits and Hares

• Losses ot agricultural production, horticulture, and forestry - $6.8 million
  • Displacement of sheep - $50 illion
• Illegal introduction of Rabbit Calicivirus Disease (RCD) in 1996 temporarily shrank rabbit populations
• Hare populations up as rabbit populations decline
  • One alien lagomorph displacing another
  • Hares damage forestry plantations through seedling browsing

Other Vertebrates

• Pigs, ferrets, rodents, and certain birds impact local production
  • Pigs prey on lambs, minor bovine TB vector
  • Ferrets are minor bovine TB vector
  • Rats and mice are pests of stored products; food industries and households
  • Sparrow, starlings, rooks, blackbirds, mynas, finches damage fruit and other crops
• Total production losses from minor pests (and insects) is NZ$10 million
• Alien vertebrates threaten natural environment and native species
• Accumulation in food chain of toxins control vertebrates
• Conflicting interests with hunting and other groups (e.g. deer, chamois, wild horses)
  • Public resistance means use of anticoagulants
  • Fear that toxins used on possums and rats will accumulate in deer and pig pose risk to hunters and dogs
• Deliberate introduction of “biocontrol agents” to control alien vertebrates
  • Rabbits controlled by weasels, myxomatosis, RCD
• Vectors of human disease
  • Possums, rodents, and hedgehogs carry Leptospirosis, Salmonella
  • Possums carry Ross River Virus carried by Aedes mosquito
  • DE (medicines, sanitation)
  • LEO (lost working time)

Summary

• Estimated costs from all pests and weeds is NZ$3.4 billion
  • DE - $1 billion
  • LEO - $2.4 billion
• Alien vertebrates is $845+ million
  • 25% of LEO ($600 million)
  • 20.7% of DE ($245 million)
• Major drain on New Zealand’s economy
  • 0.48% of GDP
• Intoducing alien species should never be taken lightly
• Follow “precautionary principle” - Alien introductions harmful unless proven otherwise

Module 5

Alien Plants in the British Isles

Introduction

• Only one previous attempt quantified native and invasive weed costs
  • Based primarily on herbicide costs
  • 2 new approaches
• Study on how to measure alien species impacts
  • Application of GISP economics program
• Critical aspect
  • Understanding how costs arise and policy options for minimizing them
  • Less emphasis on actual dollar values

Number of Alien Plant Taxa

• Exact numbers of alien and native plants unknown
• Hybrids and microspecies exacerbate problem, make it worse
• Many fertile hybrids
• Critical species are more difficult to identify
  • Rubus fruticosus has about 400 microspeices
  • Hieracium complex has about 250 microspecies
• Number of “native macro species”
  • Range from 1311 - 1552
  • Reasonable estimate, 1400 - 1500, consistent with ecological flora database
• Uncertainty about nativity of some plants
  • Those “invading” 5000 - 10000 years before present time
  • Presence of pollen grains in post-glacial deposits suspect
    • E.G., corn flower, Centaruea cyanus
• Uncertainty of alien status
• Difficulties with terminology
  • E.G., casual vs. established vs. persistent
• Adoptiong of “10s rule”
  • 10% of alien plants become casual
  • 10% of casuals become established
  • 10% of established become persistent

Equating Impacts with Costs

• Lonsdale Equation: I = R x A x E
  • I = overall impact, R = Range size, A = Abundance, E = Effect per unit
  • When one of the 3 equation components is negligible, overall impact and total cost will also be negligible
  • Applicable to many alien plants
• Other quantifiable measures - Weediness
  • Perception by scientists
  • Cost of herbicides
  • Incidence

Overview of Alien Plant Taxa

• Based on 30 non-indeginous plants
  • “Prus cost” is cost estimate for these plants
  • Costs are pounds sterling/year and its natural logarithm, e.g. 1 million or 13.816
    • Species costs based on 3 variables
      • Value of herbicide sales
      • Cost of application
      • Cost of cultivation
  • Control costs for all plant species, not just agricultural weeds
  • Fundamentally, Prus cost
    • Derived from herbicide costs
    • Rate of spead calculated from sample survey estimates
• Only 9 weed species of the 30 (about 30%) of national importance
• About 99% of Prus costs attributed to 3 arable weeds
  • Avena spp., Veronica persica
• Other species are cause for concern
  • Crassula helmsii - Aquatic weed
  • Buddleja davidii - Potential environmental weed

Impact and Cost Estimates

• Abundance
  • Measured by Sheffield survey method
    • Stratified random sampling
    • Presence of each species in 1m^2 quadrats
  • Identified 3 plant categories
    • Native
    • Planted
    • Introduced
  • A is log of abundance plotted against rank
  • Therefore, costs for both categories the same
• Range size
  • Distribution of alien plants typically smaller than natives, implies its still spreading
  • More restricted range for aliens, making impact costs less than natives
• Rate of spread
  • 100 to 200 years to reach maximum spread not uncommon
    • Forest trees take 1000 to 2000 years
  • Order of magnitude difference depends on effectiveness of human dispersal
  • 2 extensive surveys on 30 species over 30-year period
    • 10 non-significant, 6 significant at 5%, 2 at 1%, and 12 at 0.1%
    • Six most aggressive species in Figure 5.1 of course textbook
    • Thus, current cost estimates underestimate future costs
    • Since 1960 - 16 species expanding ranges
      • Epilobium, Heracleum, Fallopia, Elodea, Buddleja

Summary

• Impact of alien plants same as native when measured by abundance or weediness
• Range of aliens less than native, but still spreading
• About 9 species account for major costs
  • Weed control costs over 200 million points
• Most agricultural weeds
• Costs for natives are double that for aliens

Non-Native Invasive Arthropods and Plant Pathogens in the British Isles

Introduction

• About 30,000 non-native species brought by humans over a span of 10,000 years
• Some exotic species cause major losses to agriculture, forestry, and the environment
  • 26,000 plants introduced into Britain
  • Native flora comprises only 1600
• Most plant and vertebrate introductions intentional
• Arthropod and microbe introductions accidental
• About 5000 - 10,000 invertebrates representing 150 species imported annually
• Origin: Philippines, Costa Rica, Madagascar, El Salvador
• Since 1970s, rate of biotic invasions up significantly
• Causes: Human population growth, rapid modes of travel, environmental disturbances, increased international trade
• Impacts difficult to assess, meaning about 50% of native species undescribed
• Over 40% of threatened and endangered species are at risk of extinction due to competition and predation by non-native species
• Estimating economic impacts of non-native arthropods and plant pathogens difficult
• Sufficient data available to quantify impacts on agriculture and forestry

Insects and Mites

• About 1500 insect and mite pests cause economic damage
  • About 30% non-native
• Insects and mites damage about $3.2 billion in crops annually
  • Alien arthropods cause 30% of losses, about $960 million
• Several recent examples of non-native arthropods impacting British Isles

Mediterranean Climbing Cutworm

• Introduced on Chrysanthemum cuttings
• Native to subtropical areas of Africa, Europe, and near east
• Caterpillars grow to 5 cm
• Consume large amounts of vegetation

Western Flower Thrips

• Attacks over 244 plant species (polyphagous)
• Major pest of greenhouse crops
• Difficult to control due to insecticide resistance
• Geographic range expanding

Tobacco Whitefly

• Endemic to Central and South America
• Also, polyphagous (attacks about 500 crops)
• Poinsettias often infested
• Targeted for biological control with parasitic wasps

Leaf Miner

• 2 exotic species established in Britain
• Exhibiting resistance to pyrethroid insecticides, which is a cause for concern

Colorado Potato Beetle

• Native to the Western US
• Pest in potato production areas
• Resistant to most insecticides
• Global warming could increase damage to potatoes
  • Predicted to increase range by over 100%
  • Damage expected to increase by 76%

Cynipid Gall Wasps

• 4 exotic species attack native and introduced oaks
• Damage to oaks is serious
• Larvae create a gall on plant tissue and steal nutrients from gall
• Gall wasps attacked by native parasitic wasps
  • Provide some level of control

Forest Pests

• In total, 29 insect pests attack forest trees
  • 18 species (62%) non-native
• Major effort underway to employ different control technologies
  • Adopting IPM practices should decrease damage and losses from insect pests
• Estimated losses of forest products attributed to invasive insects, about $2 million

Plant Pathogens

• About 74% of crop plant pathogens introduced
  • Hitchhikers on seeds and other plant parts
• Economic loss from pathogens $2 billion

Fireblight Disease

• Bacterial pathogen native to North America
• Attacks following plant genera
  • Chaenorneles, Cotoneaster, Cretaegus, Cydonia, Malus, Pyracantha, Pyrus, Sorbus, and Stranvaesia

Potato Late Blight

• Responsible for Irish potato famine
• Causative agent: Phytophthora infestans
• Introduced into Ireland in 1845
  • Caused 25% yield loss
• Following year, disease was severe
  • 80% of potato crop destroyed
• During this time, about 25% of Irish population died from starvation, equaling 2 million people
• Another 1 million emigrated to the US

Summary

• About 26,000 plants, animals, and microbes introduced to Britain
• Not much known about environmental and economic impacts
• Invading insect pests and pathogens cause estimated $5 billion damage to crops and forests
• Climate change may increase attacks on crops by non-native and native pests

Module 6

Economic, Environmental, and Social Dimensions of Alien Vertebrates in Britain

Alien Species and Invasion Process

• Reasons for importing alien vertebrates
  • Sport (fishing, hunting)
  • Domestication as pets
  • Livestock for food, fur
• Most vertebrate introductions intentional
• Most vertebrates introduced for acclimatization
  • Enriching the fauna of Britain, animals and plants from around the world

Alien Species and Invasion Process - Determinants of Invasion Success

• Arrival and establishment
  • Effect of invasion pressure especially relevant
    • Number of individual introduced and number of introductions
    • Propagule pressure
• Spread
  • Dispersal ability, intrinsic rate of increase
  • Mobility
  • Climate and habitat matching

Alien Species and Invasion Process

• General rules for vertebrate invasions
  • Islands more susceptible than continents
  • Simple communities more vulnerable than diverse complex communities
• Invasions are natural processes and deliberate/accidental introductions
• Indegenous species enhanced or replaced by non-indegenous species
  • Accidental escapees
  • Deliberate releases of animals in captivity
  • Supplementing species for conservation purposes
• Impacts of alien vertebrate species
  • Consumption of other species via predation or herbivory
  • Competition with other species
  • Introduction or maintenance of disease
  • Interbreeding with native species
  • Physical/chemical environmental disturbance

Overview of Vertebrate Introductions

Mammals

• Introduced terrestrial mammals account for about 46% of extant terrestrial mammals in Great Britain
• Introduced early in human history, then later by Romans and Normans
• Introductions are accidental or deliberate
• Majority of introductions during late 19th - 20th centuries
  • “Ornamental” escapees from private estates
  • Fur production
  • Deliberate introductions

Birds

• Mobility makes it hard to determine origin
• Uncertainty about native range
• Problem worsened by supplementing native populations, eg. waterfowl
• British Ornithologists’ Union Records Committee (BOURC) avoids native vs. introduced terms
  • Preference for apparently natural state
• Introduced species are 10% of breeding bird fauna
  • Pheasant for food and sport
  • Little owl for biocontrol of small mammals

Reptiles and Amphibians

• Introduced species comprise 33% and 57% of total fauna of each group
• Virtually all pet escapes
• Reptile species
  • Red-eared terrapin
  • Wall lizard
  • Aesculapian snake
• Amphibian species
  • Midwife toad
  • Edible and marsh frogs
  • Alpine and Italian crested newts
  • African clawed and yellow-bellied toads
  • Bullfrog

Fish

• In total, 55 fish species found in Britain
• 13 established species (24%) introduced
  • Sunbleak introduced in 1990s for ornamental purposes and escaped
• As a group, most affected by introductions
  • Native ranges of some species obscured
  • Genetic diversity compromised
  • Major conservation issue
• Sport and/or ornamental purposes are main reasons of deliberate introductions
• Examples of fish introduced for sport
  • Rainbow trout, brook charr, carp, ide, wels, zander
• Examples of ornamental introductions
  • Goldfish, koi carp
• Accidential introductions
  • Bitterling, tilapia, and guppy

Economic Impacts

• Consumption of other species or crops
  • Rabbit, grey squirrel, fallow and sika deer, reeves muntjac impact forestry and agricultural crops
  • Rats and house mouse contaminate stored food
  • Mink prey on poultry, gamebirds and fish stocks
  • Canada geese consume and trample crops and grasslands
  • Exotic fish (wels and zander) prey on smaller native fish

Economic Impacts - Disease Introduction or Maintenance

• Rats and house mouse most important
  • Historically, ship rats vectored bubonic plague
• Important vector of human and livestock diseases
  • Common rat - Salmonellosis, leptospirosis, cryptosporidiosis, toxoplasmosis, yersiniosis and foot-and-mouth disease
  • Sika, fallow and muntjac deer - Bovine tuberculosis, foot-and-mouth disease
  • Ferrets, mink, native badger, and common rat - Bovine tuberculosis
  • Feral sheep and goats - Foot-and-mouth disease

Economic Impacts

• Interbreeding with native species
  • Sika deer and native red deer - Reduction in size of hybrid
  • Gray squirrel, house mouse and fat dormouse
    • Fat dormouse - Damage electric cables, roofing, and ceiling plaster
    • Gray squirrel - Enter loft spaces and cause similar damage
  • Rabbit, fallow deer, common rat, feral pig and canada goose
    • Feeding activities damage agricultural crops

Environmental Impacts

Environmental Impacts - Consumption of Other Species

• Herbivory by mammals detrimental to native vegetation, especially woodlands
  • Heavy deer browsing removes middle layer of regenerating trees
    • Detrimental to small mammals and invertebrates but possibly beneficial to birds, causing creation of ecotone
  • Heavy deer browsing at low densities (5/km^2) inhibits natural woodland regeneration
  • Coppice woodland especially vulnerable
    • Areas subjected to regular cutting to encourage suckering
    • Flow-on effects on invertebrate populations
  • Rabbits, if not excluded, negatively impact land restoration projects
  • Mink implicated in decrease of water voles, coots, moorhens, and ground-nesting seabirds
    • Predation on seabird nests and chicks leads to breeding failures of native gulls, terns, lapwings and redshanks
  • Feral cats significantly impact bird populations, decimate 33% of house sparrows
  • Overgrazing by Canada geese hurts reed beds and salt marshes
  • Introduced fish hurt native newt, frog and toad larvae, some mammals, and diving birds

Environmental Impacts - Competition with Other Species

• Native red squirrel and grey squirrel
  • Red squirrels < efficient foragers in deciduous woodlands
  • Grey squirrels attain higher densities due to faster breeding rates
  • Grey squirrel removal causes increase in number and distribution of red squirrel
• Competition between introduced mink and native otters are beneficial to otters
• Introduced trout and carp impacts aquatic communities

Environmental Impacts - Introduction/Maintenance of Disease

• In general, no evidence that introduced vertebrates transmitted new diseases
• Exceptions
  • Alien fish species introduced to supplement native stocks for recreation increased disease in fish populations
  • Parasitic worms in pheasants harmful to native gray partridge

Environmental Impacts - Interbreeding with Native Species

• Three introduced mammals implicated: Feral ferrets, cats, and sika deer
  • Ferrets and native European polecat
  • Feral cats and native wildcats
    • Hybridization occurring for several hundred years
    • Does not appear to have bad effect on population persistence
  • Sika deer and native red deer
    • Able to maintain species integrity where allopatric populations occur
    • Hybrids better competitors in dense woodland, may replace red deer
  • Ring-necked pheasant and lady Amherst’s pheasant
    • Both introduced, not conservation threat
  • Ruddy duck and native white-headed ducks
    • Fertile hybrids lead to extinction of white-headed ducks
  • Italian crested newt and great crested newt
    • Viable hybrids but low fertility, making it a dead end
  • Marsh/edible frogs and pool frogs
    • Pool frogs may not be native
    • All 3 capable of interbreeding
      • Male pool and female marsh frogs make edible frogs
      • Edible and pool frogs make green frogs
  • Fish hybridization is a frequent occurrence
    • Movment of native and introduced species helped by humans
    • 3 hybrids
      • Brook charr and native trout
      • Ide and native bream
      • European carp and native crucian carp

Environmental Impacts - Environmenal Disturbance

• Rooting behavior of feral pigs affects ground cover flora and diversity
  • In Hawaii, feral pigs feed on invasive strawberry guava, spread seeds
  • Invasive fruit flies feed on rotting fruits
• High pheasant populations disturb soil and increase nutrient loads, causing more weeds
• Feeding behavior of carp increases water turbidity, reduces light available to aquatic plants

Environmental Impacts - Environmental Benefits

• Rabbits
  • Significantly increase floral diversity and rare butterfly population
  • Provide 75% of diet of mammalian predators
• Mandarin duck - Britain provides refuge for alien populations of this bird
• Brown hare has action plan developed to increase numbers and range

Social Dimensions

Cultural Associations

• Public bias towards charismatic pests makes invasive species management contentious
  • Perception is some invasive species more desirable to save than others
  • Hedgehog
    • Wading bird populations in Scotland leads to egg predation
    • Protected species in Britain
    • Hedgehog culling raises outcry from animal rights groups and public
    • Popularity of hedgehogs ended culling project in Scotland
• Wild boar
  • Extinct in Britain about 700 years ago from overhunting, habitat loss
  • Re-established for hunting, leading to escapees, wild boar farms
  • Negative public response due to fear of human attacks, although no confirmed reports
  • Fear of wild boars subsided due to decrease in hunting opportunities

Public Attitudes

• Cultural background affects how humans perceive the natural world
• Bias in conservation research/management projects
• Knegtering et al. (2002) study
  • Birds more likeable than mammals
  • Invertebrates least liked
• Non-governmental organizations (NGOs) give species characteristics, taxon and relative size in support for/against conservation
• Attitudes towards invasive species based on species type, impact, and proposed control method
• Response to lethal control methods mixed
  • Acceptable if controlling livestock predators
  • Aversion for hunting, justifiable for protecting rare speices
  • Negative effects of non-lethal methods make lethal methods justifiable
• Separation of society from processes of food production affects emotional repsonse to wildlife

Social Benefits

• Improving community wildlife awareness
  • Re-establish children’s connection with nature and wildlife conservation for future generations
  • Positive promotion of environmental awareness is important for increasing urban populations
• Aesthetic characteristics of invasive species
  • Invasive grey squirrels promoted for community wildlife awareness instead of native red squirrel
  • Media plays role in shaping attitudes
• Recreational activities
  • Hunting birds and mammals for food and sport
    • Pheasant, red-legged partridge, Canada goose
    • Sika deer, rabbit, wild boar
    • Pheasant hunting is a multi-billion-pount sport industry

Analysis and Conclusions

Impact of Environmental Change

• Native speices 15,000 years ago
• Vertebrate fauna species poor in ice age
  • Native mammalian fauna, mixture of European and Scnadavian origins
• Number of mammalian introductions over all other taxa
• Birds more abundant
  • Crane in Britain, 1981
• Habitat change is most important driver of invasive species populations
  • Increase in broad-leaved scrub and woodland cover from biomass energy sources
  • Improved habitat for deer populations

Anthropogenic Native Species Extinctions

• Extinction of about 33% of Britain’s native fauna caused by human actions
  • E.g., reindeer, elk, brown bears, lynx, wild boars, beaver, and wolf
• Effects of competition
  • Non-native birds, amphibians, and fish faring better than mammal invaders
• Control and mitigation costs
  • Environmental damage difficult to quantify

Control and Mitigation Costs

• Deer is 2.5 million pounds
  • Shooting more cost-effective than fencing
• Rabbits 30 million pounds per year
• Rodents 15.3 million/year (rodenticides)
• Feral cats 2.6 million (trapping, neutering)
• Game birds
  • Canada goose, primarily shooting (license fees)
  • Ruddy ducks 3.4 million pounds for eradication
  • Pheasants, sport shooting generates about 800 dollars per day/hunter
• Amphibians and fish have no relevant data

Vertebrates and Invasion Theory

• Invasion pressure affects number of introductions
• Populations often enhance artificially through rearing programs
  • Pheasants, carp, rainbow trout
• Tens rule: 10% of introduced establish, 10% of those become pests
• Curent vertebrate populations exceed rule if environmental impacts added to economic
  • Rabbits impact British ecosystems
  • Other vertebrate populations increase thanks to habitat and climate change

Changing Attitudes About Nature

• Current thinking is that humans are part of the natural world, not separate from it
• Increase concern for animal welfare
  • By working class, not aristocracy
• Disdain for scientific use or leisure purposes
  • Anti-hunting and fishing
• Formation of numerous animal rights groups
  • Consequence of less emphasis on eradication of invasive species
  • Public concern for squirrel and rabbit control

Future of Britain’s Alien vertebrates

• Alien species compromise about 50% of current mammalian and avian faunas
• Some species positively contribute to environment and economy
• Others impose significant costs
  • 230 million pounds
  • Rabbits cause most damage
• Monitoring is necessary for other species that may be increasing

Invasive Plant Pathogens in Europe

Introduction

• Late 19th century, grapevines and potatoes destroyed by pathogens
• Great invasions lead to development of the field of plant pathology
• First, regulatory measures considered
  • 1891, Danish plant pathogen first to propose measures prohibiting importation of contaminated plants and seeds
  • 1951, IPPC established framework for phytosanitary measures against invasive species, formation of EPPO
• EPPO developed international strategy preventing introduction and spread of plant pests affecting agricultural and natural areas
• EU established in 1993, integrated quarantine pest lists and phytosanitary measures
• Currently, about 300 quarantine pests identified, many are plant pathogens
• IUCN invasive species: Species with potential impact on biodiversity (excludes pathogens affecting crops)
  • Recognizes only 3 pathogens
    • Dutch elm disease
    • Phytopthora disease, which affects 900 trees
    • Chestnut blight
  • Does not include pine canker disease (DAISIE only)

Recent Pathogen Inventories

• Reencounter effect
  • Pathogens introduced decades/centuries after crop plant leads to loss of resistance
  • Exemplified by potato blight in Ireland
• Narrowing of genetic diversity in crop plants, which favors fungal attacks
  • New pathogens emerge as virulent pathotypes of established species
• Examples
  • Yr17 yellow ruse in Europe
• Delivering Alien Invasive Species Inventories for Europe (DAISIE) consortium
  • First inventories of alien species in Europe
  • Highest number of pathogens in France, UK, Germany, Italy
  • Level of imported goods is best predictor
  • Origin of pathogens is North America and Asia
• French inventory
  • About 230 fungi recorded since 1800
  • Ecological categories: Plant pathogens > mycorrhiza > sapotrophs
• >50% attack woody plants
• 3 important disease groups have wind-borne dispersal and visible damage
  • Downy mildews
  • Powdery mildews
  • Rusts
• UK inventory - 1970 - 2004
  • About 230 fungi, bacteria, phytoplasma, viruses
    • About 80% fungi, most on ornamental species
• New detections in greenhouses and protected agriculture
  • Transport of contaminated plant material from the Netherlands

Cultivated Plants - Downy and Powdery Mildew

• Introduced from US in the 19th century
• Threaten grapevine and wine production
• Fungicide use mandatory, up to 90% usage
• Total cost for France >180 million french dollars for 600,000 ha

Cultivated Plants - Potato Late Blight

• Main potato disease in Europe
• Fungicide use 59% of total worldwide
• Yield losses about 35% without fungicides
• Annual losses in Ireland about 8 million pounds annually
• 4 countries account for most potatoes
  • UK, Belgium, France, Netherlands
• First observed in 1870 and then in 1883
  • Carried on potatoes imported by Europeans
• Can cause about 70% reduction in susceptible potato varieties

Economic Impacts

Fungi and Oomycetes

• Forestry and amenity trees
  • 4 fungi attack trees with significant impacts
    • Dutch elm disease 124 million
    • Unspecified pathogens 1.8 billion
  • Canker stain of plane trees (sycamores)
    • Introduced by American military in WWII
    • Highly virulent, affects urban plantings
    • Tree removal mandatory for infected tree and two neighboring trees, replant with resistant trees
    • Economic impact 1700 per tree
    • Spreading to natural forests in Italy

Bacteria and Phytoplasma - Flavescenece doree

• Phytoplasma disease of grapevines
• Vectored by beetle Scaphoideus titanus
• Effects magnified by wine production loss

Bacteria and Phytoplasma - Potato Brown Rot

• Bacterium, Ralstonia solanacearum R3 B2
• Quarantinable ad mandatory eradication
• Native alternate host, Solanum dulcamara in UK

Bacteria and Phytoplasma - Fire Blight

• Bacterium attacking fruit tree orchards
• Introduced from North America during 20th century
• Introduced in Switzerland about 1989

Viruses - Plum Pox (Sharka Disease)

• Threatens prunus spp.
  • Plums, cherries, peaches, apricots, and almonds
  • Discovered in Switzerland in 1967
    • Cost of 1st eradication campaign cost 340 million
• Estimated fruit losses
  • Europe last 30 years, 5.4 million
  • Mediterranean last 20 years, 576 million
  • Worldwide costs 10 billion

Ecological and Predicted Pathogen Impacts

Ecological Impacts

• Natural tree area underestimated
  • Mortality caused by Dutch elm disease in the UK
    • About 50 million elm trees (mature and young)
    • Comparable losses in Europe, Asia, and North America
  • Costs of losing irreplaceable species
    • Loss of ecological services and biodiversity difficult to quantify
    • Economic and ecological impacts are highly correlated, should be assessed together
    • Data available for provisional impacts, data on cultural impacts scarce
  • 20% loss of ecosystem services in France
    • 1.4% loss in “forest value” from fungi
    • 400-800 million annually

Predicted Pathogen Impacts - Pest Risk Analysis

• Pest Risk Analysis: Process of evaluating evidence to determine whether a particular organism is a pest, whether to regulate it, and strengthen phytosanitary measures
• ISPM provides guidance for PRA
• EFSA performs PRAs for EU
• PRAs often lack transparency and repeatability
• Wheat Karnal bunt fungus, EPPO A1 list
• Potato spindle tuber viroid, “A2”
  • Detected in solanaceous ornamentals, Brugmansia, S. Jasminoids
  • Pepino mosaic virus on glasshouse tomatoes
• PRATIQUE - 2008
• Translation - enhancements of pest risk analysis techniques
• EU funded project to overcome lack of sufficient data to conduct PRAs
• Objective is to enhance techniques for assessing economic, environmental, and social impacts of quarantinable pathogens

Predicted Pathogen Impacts

• Future prospects
  • Drivers of increase in invasion rates
    • UK - Number of ornamental and crop pathogens introduced since 1970s not increasing over 5-year periods
    • France has lower invasion rates, 2 new species annually
    • Species alien to UK are indigenous to EU
  • Rate of introductions exponential since 1800s for all of EU

Emerging Plant Pathogens

• Bacterial watermelon fruit blotch
  • Seed-borne disease
  • Reported from Greece, Israel, Hungary, Turkey
• Common ash dieback
  • Fungus of ash trees discovered in Poland
• Pine wood nematode
  • Native to North America
  • Threatens European forests
  • Currently impacting forests in Asia
  • Intercepted in packing material
  • Disease outbreak on Portugal’s maritime pines
• Sudden oak death fungus
  • Spreading in commercial nurseries and forests
• Riparian alder fungus
  • Virulent hybrid of 2 less aggressive forms
• Tomato yellow leaf curl virus
  • Vectored by whiteflies
  • Damage vegetable crops, especially tomatoes
  • Outbreaks result in total crop failure
  • Linked to spread of whiteflies, range expansion via global warming and international trade

Plant Pathogens Absent From Europe

• Citrus greening (HLB)
  • Severe citrus disease
  • Vectored by Asian citrus psyllid
  • Poses high risk to the Mediterranean
• Citrus canker
  • Prohibition on importation of citrus plants
• Pierce’s disease
  • Primary disease of grapevines
  • Threatens grape and wine production
  • Insect vector (glassy-winged sharpshooter) not present in Europe, transmission not vector specific
  • Prohibition on importation of grapevines

Summary

• Invasive plant pathogens threaten cultivated and native plants
• Old pathogens still have major impacts
• Less fungicide use and more sustainable methods of disease management required
• Native plant communities vulnerable due to increased international trade
• Strict enforcement of quarantine rules
• Quarantine lists on PRAs must be updated
• Need to consider pathway approach for preventing pest and pathogen movement

Module 7

Invasive Patterns of Alien Terrestrial Invertebrates in Europe

Introduction

• Invertebrates are the majority of living organisms and major invasive species problem
• Compared to other major countries, Europe is not concerned about invertebrates
  • No checklists of alien species produced until last decade
• Recently introduced economic pests raising awareness of problem
  • Corn rootworm, Asian long-horned beetles, Asian tiger mosquito, pine wood nematode, horse chestnut leaf miner

Key Factors

• Weakening customs and border controls within EU facilitate spread between countries
• DAISIE project
  • Initiated in 2005
  • Compiled a pre-2008 inventory of alien species in Europe
  • Revealed dominance of alien plants (55%) followed by invertebrates (23%)
  • In 2010, a total of ~1,600 alien arthropods identified

Asian Connection

• Asian insect herbivores are better colonizers
  • Arthropods (mainly insects) comprise ~94% of alien fauna
• ~14% cryptogenic
  • Cosmopolitan species of uncertain origin
• Most invertebrates unintentionally introduced
  • Ornamental and aquarium plants, cut flowers, stored products, fruits and vegetables, wood products, soil, animal husbandry, used tures, etx.
  • E.g., Asian tiger mosquito
• Only 14% of alien arthropods purposefully introduced
  • Silk production, pet arthropods, food for pets
  • Biocontrol agents
    • Harlequen and ladybeetle
    • Parasitic wasps

Trophic Patterns

• Trophic: Feeding patterns
• Herbivorous insects are the dominant group
  • ~50% via explosive plant trade
• Establishment of alien vertebrates
  • Exponential increase since 16th century
  • Acceleration since late 20th century
• Disestablishment of internal customs procedures following 1993 formation of EU records introduction and spread
• Major groups of woody plant invaders largely undetected

Asian Connection Redux

• Asia is a major source of alien invertebrates since early 20th century
  • Moths and bugs originate from Asia
  • Mites, wasps, and flies from North America
  • In general, dispersal of detritivores is greater than herbivores, predators, and parasitoids
• Once established, spread of alien invertebrates surprisingly slow
  • On average, dispersal linearly correlated with establishment duration
  • Exception in subterranean termite
    • Still only present in France after 200 years

Alien Vertebrate Distribution

• European countries differ in total numbers of alien invertebrates
  • Italy, France, and Great Britain lead all other countries
• Number reported, positively correlated with key factors
  • Surface area
  • Macroeconomic variables
    • Road network size
    • Volume of merchandise and agricultural imports
• National wealth and human population density
• Intensively disturbed habitats

Human Role

• Alien invertebrates and human-modified habitats
• Disturbed urban areas have lower resistance to invasion
  • Lack of natural enemies
  • Less vigorous host plants
• Some species prefer human habitats in native range
• Example Asian long-horned beetle
  • Restricted to urban areas planted with poplar
  • Found in natural forests dominated by maples

Impacts of Alien Invertebrates

• Modified composition of European fauna
  • 30 new families since alien arrival
• Dramatic change in guild composition likely to affect ecosystem structure and function
• Phytophagous insects dominate alien fauna, some with serious consequences
  • Pine wood nematode threatening pine forests
  • Emerald ash borer threatens ash forests in Russia
  • Red palm weevil attacks endangered palm species
  • Seed wasps reduce yield of rose seeds
• Biocontrol non-target impacts
  • North American aphid parasitoid displacing 2 Mediterranean congeners
  • Asian ladybeetle harmonia reducing niches of native ladybeetles
• Beekeeper impacts
  • Hornet serious bee predator in France
  • Varroa mite is a bee parasite
• Economic impacts
  • Serious pests of agricultural, horticultural, and forestry
  • In the UK, US $960 million
  • Fore the entire EU, estimated losses of 10 billion
  • Regulatory measures exclude Colorado potato beetle and Western flower thrips

Colorado Potato Beetle

• Defoliator: Removes leaf tissue from the plant
• Global warming could exacerbate damage to potatoes
• Predicted to expand range by >100%
• Damage expected to increase by 76%

Western Flower Thrips

• Causes curling in leaf tissue prevents plant from completing development
• Attacks >244 plant species (polyphagous)
• Major pest of greenhouse crops

Impact of Alien Vertebrates - Human and Animal Health

• Asian tiger mosquito nuisance and disease
• Rat fleas transmit viruses and bacteria
• Chewing lice are cryptogenic pests of poultry and mammals (skin infections in dogs and sheep)
• Ticks cause irritation and are disease vectors
• Spiders bite humans
• Endoparasites of veterinary importance
  • Nematodes and flatworms affect livestock, game animals, and humans
  • Mites affect birds and humans
• Cockroaches cause asthma and diarrhea, and transmit diseases

Impact of Alien Invertebrates

• Since 2010, ~1400 alien insects recorded in Europe
• Three alien insect orders dominate the landscape
  • Coleoptera, Hemiptera, Hymenoptera account for ~75% of total
• Taxonomic composition of alien fauna differs
  • From native fauna
  • Hemiptera 3x more represented in alien than native

Module 7

Impacts of Alien Vertebrates in Europe

Introduction

• Alien species imported for various purposes
  • Domestic pets
  • Recreation (hunting, fishing)
  • Food
• Once introduced
  • Reproduce
  • Establish self-sustaining populations
  • Disperse
  • Expand populations
• Without natural enemies, impact invaded ecosystems and humans

Mammalian Introductions

• Began in Neolithic period (9000 - 8000 years BC), wild animals associating with humans
• Since 1500, ~88 alien mammals introduced to Europe
  • ~20 native to some other part of Europe
  • ~70 native to Asia and North America
• 72% alien mammals established
• Introductions increased exponentially since mid-1800s
  • Majority introduced for hunting
  • Improvement of local fauna
• Currently, 59 species invasive in Europe

Alien Mammal Impacts

• Economic
  • Damage crops, impact livestock, humans
• Ecological
  • Competition, hybridization, predation
• Rats, mink, and nutria cause highest environmental impact
• Economic impacts evenly distributed among 15 families
  • Health impacts include disease transmission
  • Environmental impacts include herbivory
  • Economic impacts include livestock and forestry

Alien Mammal Impacts - Biodiversity Impacts

• American mink and raccoon dog
  • Carnivore and omnivore
  • Prey on native birds, mammals, and amphibians
  • Compete with native mammals for food and den sites
  • Mink linked to decline of 30 native species
• Sika deer
  • Introduced for hunting and ornamental value
  • Heavy foliage browsing decreases understory biodiversity
  • Hybridization with native red deer
  • Transmission of nematode parasites to native deer
• Grey squirrel
  • Rapidly expanding population in Italy
  • Outcompetes native red squirrel

Alien Mammal Impacts - Economic Impacts

• Muskrats and nutria burrow into riverbanks and damage sugar beet crops
  • ~12 million in Germany and Italy
• Mink impacts chicken production and fisheries
• Raccoon dog damages vineyards in Ukraine
• Sika deer damages oats, soybean, and corn crops in UK and Switzerland
  • Also, forest plantations
• Fallow deer likewise damage vegetable, fruit, grain crops, tree plantations
• Gray squirrel strip off tree bark
  • Tree death or inferior wood products
  • Damage to broad-leaved trees > conifers
  • ~87% tree stands affected
• European rabbit
  • 11th century, Romans and Normans
  • Damage to crops, tree plantations, vineyards
  • In 1980s, total damage in UK 130 million pounds

Alien Mammal Eradications

• Most control and eradication efforts target mammals
  • Cause greater impacts than other vertebrates
• Several successful eradications
  • Coastal islands of Britain, Spain, Portugal, France, Italy
  • Species targeted include rats, mink and rabbits
• 4-point global strategy
  • Description of problem
  • Performing and monitoring eradication efforts
  • Assessing impacts on native species
  • Establishing protocol for preventing new invasions
• Fewer eradications on mainland Europe
  • Legal support, public awareness and funding inadequate
    • Grey squirrel eradication opposed by PETA groups in Italy and Great Britain
  • Successful eradication of nutria in Britain
    • 1929 - Introduced for fur farming
    • 1950s - Populations up to tens of thousands
    • 1981 - Successful trapping program

Predicted Impacts and Management

• 35% range expansion of several mammals since 2000
  • Mink, nutria, sika deer, raccoon
• Species with localized distributions good candidates for eradication
  • Siberian chipmunk impacts grain and nut crops in Italy, UK, Germany, Netherlands, and France
  • Well-organized eradication programs could be effective
• Preventing sale of potential invaders in pet shops limits new introductions

Bird, Reptile, and Amphibian Introductions

• ~200 bird species introduced since 1850
  • Most species since 1940s
• In total, 55 reptiles and amphibian species, slower rate than birds
• Highest numbers of non-mammalian vertebrates in western Europe
• Many introductions intentional
  • Hunting and fishing
  • Improving local fauna
  • Escaped pets and zoo animals

Impacts of Birds

• Documented impacts for ~46% of alien breeding bird populations
  • Economic includes agricultural damage (grains, fruits)
  • Biodiversity includes competitive interactions
    • Declines, predation or hybridization with natives

Impacts of Birds - Examples of Biodiversity Impacts

• Ducks, geese, and swans
  • Damage shoreline habitats
  • Pollution of water bodies
  • Competition for breeding sites
  • Hybridizing with native waterfowl
    • Genetic introgression meaning extinction
    • Ruddy duck and white-headed duck
• Sacred ibis
  • Predator of water birds and amphibians
• Rose-winged parakeet
  • Displaces native cavity nesting birds
• House crow and common myna
  • Both listed as “100 of world’s worse alien species”
  • Native species declines via predation and competition
  • Disease vectors of humans and wildlife

Impacts of Birds - Examples of Economic and Human Impacts

• Canada geese
  • Reduce crop yields by 20%
  • Airplane collisions
• Pheasants
  • Introduced for hunting - Positive impact
  • Damage grain crops - Negative impact
• Alien bird eradications
  • Ruddy duck and myna targeted

Future Predicted Impacts

• Major impact associate with certain traits
  • Invade variety of habitats
  • Produce > 1 brood per season
  • Form large feeding or roosting flocks
• Future bird, amphibian, and reptile introductions
  • Consequence of pet trade
  • Imported wild-caught birds infected with Avian flu banned in 2005
• To date, only 12% of alien birds established in 1 country have spread beyond that country
• Effect of climate change
• Most introduced as pets or food
• Major impacts include loss of biodiversity
  • Predation
  • Competition
  • Pathogen transmission
• Impacts of amphibians 2x that of reptiles
• American bullfrog
  • Invades wide range of habitats
  • Feeds on native frogs, snakes, and turtles
  • Vectors fungus responsible for amphibian
  • Declines worldwide
  • Successful local eradications in UK, Germany
• Common slider turtle
  • Feeds on native reptiles, amphibians, small mammals, birds
  • Competes with native turtles for resting and basking sites

Prioritizing Alien Invasive Birds

• Impacts on biodiversity
• Impacts on economic resources
• Impacts on human health and well-being
• Quantifying impacts
  • Minor impact
  • Major impact

Summary

• Advantages of objective ranking system
  • Prioritize species with limited funding
  • Rankings can be updated when new information becomes available
• Species with limited distributions have eradication that is feasible and cost-effective
• Widespread species require coordinated effort between countries and public education

Module 8

Alien Plant Pathogens in Brazil

Introduction

• First crop plants introduced by Portugese explorers in 16th century - Citrus, sugarcane, wheat
• Cultivation of other crops occurred later - Coffee, bean, maize, fruits, vegetables, grain
• Seedlings of these and other crops - Introduced over the next 400 years without phytosanitary standards
• Biotic causes of diseases not understood until late 19th century - Koch’s postulates
• Koch’s postulates
  • 1890, Robert Koch, German bacteriologist
  • Cause-and-effect relationship between pathogen and disesase
• Procedure
  • Pathogen - Isolated from host with disease and grown in pure culture
  • Disease - Reproduced when pure culture pathogen is inoculated into susceptible host
  • Pathogen - Recoverable from experimentally infected host
• Favorable environment and susceptible hosts - Introduction and establishment of numerous pathogens
  • Fungi, bacteria, nematodes, and viruses
• Consequences of pathogens
  • Yield losses, increased production costs, environmental pollution, toxicants, lower crop market value
  • Energy loss, low seed emergence, decreased nutritional value, long fallow periods
• Total losses ~$6.9 billion

Impacts

Agricultural Practices

• Low crop productivity
• Social and economic considerations
  • Substinence growers account for 80% of rural farms
  • Lack of technical assistance and resources
• Poor disease management - Large yield differences for bean crops (>2.5x)
  • Small farms - 700 kg/ha
  • Commercial farms - 1800 kg/ha

Cultural Practices

• Contribute to pathogen spread, soil degradation, and environmental pollution
• Practices include
  • Intensive soil use, poor sanitation, planting monocultures, insufficient crop rotation, and inefficient irrigation
• Create ideal conditions for air and soil-borne pathogen epidemics
• Higher disease intensity from minor pathogens

Major Crop Pathogens in Brazil

Soybean Pathogens

• Soybeans cover 40% of grain area
• >40 pathogens cause $1 billion in losses
  • Yield reduction, decreased quality, poor seed emergence
• Major diseases include soybean stem canker, cyst nematode, and late foliar disease complex
  • Stem canker discovered in 1988 - Resistant varieties
  • Cyst nematode detected in 1992 - Improved cultivation practices
  • Foliar diseases - Fungicides

Maize Pathogens

• Demand for animal feed increased maize crop areas and second harvest (safrinha)
• Safrinha - High inoculum pressure
• Plant diseases main constraint to crop production and yield loss
• Phaeosphaeria maydis discovered in 1902
  • Key pathogen due to crop residues, susceptible varieties
  • Kills smaller maize plants, reduces kernel size
• Since 1995, increase in maize and bushy stunt, fine stripping disease
• New cercospera leaf spot recorded

Common Bean Pathogens

• Grown year-round with short continuous rotations
• Intensive cropping creates ideal conditions for foliar diseases
  • Anthracnose, angular leaf spot, rust fungus
• Increasing dependency on foliar fungicides leads to problems with soil pathogens
• Sclerotinia sclerotiorum most important soil-borne pathogen
  • First recorded in 1920
  • Severe epidemic in 1976 in Parana state
  • Present in all bean crop areas
  • Can cause 100% yield loss

Rice, Wheat, and Small Grain Pathogens

• Rice blast - Most important disease of rice
• Yield loss - Can reach 100% if not managed
  • Found infecting wheat and rye in 1985
  • Small grain diseases increased during transition from traditional to no-till systems
• Crop residue accumulation on soil surface, increase in leaf spotting pathogens
• Seed treatment with fungicides and crop rotation - Effective in controlling speckled leaf blotch (Septoria tritici)

Vegetable Pathogens

• Solanaceious, cucurbits, carrot, and lettuce crops intensively cultivated year-round
  • High production costs, susceptibility to pathogens and chemical dependency
• Leading vegetable crop is potatoes
  • Susceptible to major alien pathogens
• Tomato varieties and hybrids also vulnerable
  • Poorly adapted to Brazil’s environment
• Disease outbreaks - Poor sanitation, improper chemical spraying, continuous production
• Viruses and nematodes - Tropics
  • Increase in tomato Geminivirus diseases since 1997 - Spread of whitefly (Bemisia spp.)
  • Low productivity from Geminivirus infection - Tomato pinworm problems
• Greenhouse crops - Monocultures and high plant density, vulnerable
  • Eggplant and bell pepper crops - Weekly fungicide sprays to manage powdery mildew

Tropical and Temperate Fruit Pathogens

• Fruit spot and decay diseases from pathogens - Major constraints to fruit exports
• Leaf and fruit spots - Native pathogens
• Nematode and protozoa - Examples of alien pathogens affecting coconuts
• Grape vine canker detected in 1998
  • Infects red globe and seedless grape varieties

Orange Pathogens

• Citrus production since 1930s
  • 80% of orange crop - San Paolo and Minas Gerais states
• Main diseases A2 pathogens
  • Limited distribution and under control
  • Citrus canker, variegated chlorosis and black spot
• Chlorosis disease discovered in 1987
  • Spread by leafhoppers and infected seedlings
  • Fruit with no market value, $130 million in losses
  • Genome sequencing to control disease, $15 million
• Citrus canker first reported in 1957
• Infected stems introduced via Southeast Asia
• Spread exacerbated by citrus leaf minder
• Caused $500 million loss from 1998 - 1999
• Tree removal required for disease eradication
• December 2000 - Disease foci reduced from 4,000 to only 67; 98.3% reduction

Banana Pathogens

• Brazil is 2nd leading producer and 1st consumer
• Black Sigatoka disease found in 1998
  • Most destructive disease of bananas and plantains
  • Spread by infected plants, fruits, or conidia on tires, wood, and clothes
• 100% yield losses for high-priced banana cultivars and 60% for plantains
• Controlled by fungicinddes but requires 40 spray applications at $1000/ha
• Restriction on movement of infected fruit best tactic

Phytosanitary Standards, Chemical Control, and Future Trends

Phytosanitary Standards

• Rigid federal laws to prevent entry and spread of exotic pathogens in Brazil
• No laws establishing seed health
  • Legislation held up by seed industry lobby
• Tolerance levels to adventive pathogens
  • Individual states - Make and enforce laws
• Intraspecific pathogen diversity and high inoculum levels decrease viability of resistant varieties - Breaks down in 2 - 5 years

Chemical Control

• All fungicide and antibiotic sales target alien pathogens
• Southern and southeast regions - 72% of fungicide consumption
  • Sao Paulo state responsible for 33%
• Many growers began chemically treating seed in 1990s
  • Increases crop yields and reduced need for field spraying
• Field spraying - Economically feasible for small grain crops
• Multiple sprayings - High-value potato crops
• Inadequate training of growers
  • Spraying without establishing disease thresholds
  • Use of non-registered fungicides
  • Wrong spray nozzles/no calibration of sprayers
  • Container storage and disposal guidelines ignored
• 1990 - Potato and tomato crops - 41% of fungicides sold, followed by citrus (19.6%) and coffee (11.3%) - High risk of environmental pollution
• Illegal practice of “chemigation” - Threat to environment

Future Trends

• Prevent entrance of new pathogens
  • Improve nation’s plant inspection system
  • Develop efficient methods for detection
  • Establish laws to regulate plant transport
• Improve control of established pathogens
  • Adopt efficient IPM practices - Disease resistant varieties, improved cultivation techniques, and proper fungicides
• Expanding organic market - Reduction and/or elimination of pesticides

Invasive Vertebrates in Brazil

Introduction

• Brazil is characterized by six diverse ecosystems
  • Amazon (forest)
  • Cerrado (grassland)
  • Caatinga (desert)
  • Pantanal (wetlands)
  • Pampas (open-field)
  • Atlantic rainforest
• Suffer from human disturbance and loss of biodiversity from habitat fragmentation and invasive species
  • Interchange of flora and fauna since the 1500s
• Invasive species defined by CBD (1992)
  • Introduced species - Spread without human assistance and threaten natural environments outside original range
• First documented invasive species
  • Insect: African malaria mosquito, Anopheles gambiae
  • Reptile: House gecko, Hemodactylus mabouia
  • Fish: Carp, cyprinus carpio
• Establishment of government and non-governmental databases to document invaders

Invasive Fish, Amphibians, and Reptiles

Invasive Vertebrates

• Fish and mammals compromise the highest proportion of Brazil’s invasive vertebrates
• ~138 (2.1%) non-marine vertebrates considered invasive in Brazil
  • Fish (4.3%)
  • Mammals (2.5%)
  • Reptiles (0.7%)
  • Amphibians (0.4%)
  • Birds (0.2%)

Fish

• 9% of all freshwater fish species worldwide - Native to Brazil (233 species)
• 109 species of freshwater bony fishes - Invasive in Brazil
• Main causes for exotic introductions
  • Improvements of culture ponds, aquariums
  • Sport fishing and mosquito control
  • Unintentional elimination of natural barriers from hydropower impoundments
• Life history attributes - Affect invasion and establishment success

Invasive Fish Families - Characidae

• Most abundant family; neotropicla origin
• In total, 17 species invasive in upper Parana basin, both lentic and lotic habitats
  • Lentic - Lakes, ponds, etc.
  • Lotic - Rivers, streams, etc.
• Exceptional swimming ability contributes to invasiveness

Invasive Fish Families - Cichlidae

• Cosmopolitan group
• Second most important invasive freshwater
• Fish group with 15 species
• Mainly lentic species
• Introduced into Brazil for aquaculture

Invasive Fish Families - Cyprinidae

• Third most important invasive freshwater
• Fish group with 14 species
• Worldwide distribution - Native to Eurasia, Africa and North America
• Also introduced into Brazil for aquaculture

Invaisve Fish

• In total, 26 species of extra-neotropical origin stocked as sport fish or dish culture
• Guppies (Poecilia) and Ramirezi (Mikrogeophagus) introduced as aquarium fish
• Widespread in 6 hydrographic regions
• Guppy introduced into Brazil for mosquito control
• Currently, stocking of non-native fish in public waters forbidden
• Tilapia and African sharp tooth catfish - Most widespread exotic fish in Brazil
• Important in fish culture and adaptable to tropical climates

Native Transposed Fish

• Many native species transposed since 1960s
• Movement from amazon basin into other regions of Brazil
• Example: Golden dorado
  • Drastic consequences for native species displacement
  • Voracious feeding habits impacting 2 native Brycon species
• Hydropower impoundments often associated with biological invasions

Amphibians

• 3 frog species considered invasive in Brazil
  • Labyrinth frog
  • Common bullfrog - Introduced for raniculture
  • Pipid frog - Pet trade
  • Exotic species but invasive status debatable
• These frogs constitute ~33% of Brazilian amphibian fauna
• Labyrinth frog of neotropical origin, whereas other 2 species of extra-neotropicla origin
• Overall, number of invasive amphibians - Low relative to other vertebrates

Reptiles

• In total, 5 invasive species in Brazil - Represent <1% of reptile fauna
• Gekkonid lizard
  • Most widespread in urban areas
  • Host for parasites of native fauna
• Sand lizard
  • Widespread in Restingas (sand-dune habitats)
  • Well-established populations
• Teiid lizard
  • Introduced in 1950 for biocontrol of mice and rats
  • Poses threat to terrestrial birds (egg predator)
• Water tortoises (2 species)
  • Former pets - Escaped or released into natural areas

Invasive Birds and Mammals

Birds

• 4 bird species invasive in Brazil
• Blue fronted parrot (Amazona aestiva) - Population established on Santa Catarina island
• Pigeon (Columbia livia)
• Common waxbill (Estrilda astrild) - Native to South Africa, introduced by merchant sailors
• Sparrow (Passer domesticus) - Established on all continents, introduced to Brazil in 1906 to control mosquitoes in Rio de Janiero
• Pigeons and sparrows - Ecosystem impacts

Mammals

• In total, 16 invasive species, primarily from Asia and Europe
  • Rodents (rats and mice) - Introduced via ships during the discovery and colonization period
  • Dogs and cats - Introduced and widespread
  • Eradication feasible - Castration combined with other lethal methods
    • Prey poisoning and viral disease
  • Problems with lethal control methods
    • Non-target impacts
    • Rejection by local residents

Mammals - Feral Cat Impacts

• Cause major declines in small vertebrate populations
• Reservoir host for several diseases
  • Carnivore tapeworm, Toxoplasmosis (native species)
  • Sarcosporidiosis (sheep)

Mammals - European Hare

• Introduced in S. America - Late 19th century
• Competes with native rabbit species

Mammals - Feral Pigs

• Introduced by settlers in 16th century and/or late 19th century during Paraguayan war
• Recognized as pests worldwide
• Negatively impact ecosystems
• Transmit diseases
• Potential to displace native Brazilian Peccaries
• Considered wildlife and protected by law

Mammals - Goats

• Arrival in Brazil not by European settlers
• Introduction occurred via 2 steps
  • Undefined breeds - 16th to 18th centuries
  • Arrival of modern breeds - Late 19th century
• Largest populations in Northeast Brazil

Mammals - Water Buffalo

• Introduced in late 19th century
• Used for meat and diary production
• 1.6 million heard in Brazillian Amazon
• Environmental wetland damage
• Government ignored risks associated with water buffalo in Pantanal region

Mammals - Invasive Mammals Native to Brazil

• How can there be invasive mammals invasive to Brazil?
  • They were moved from one region of the country to another (transposition)
• Common and black-tufted marmoset
  • Captured and sold as pets
  • Negatively impact bird populations, lizards, tree frogs and mammal infants
  • Destroy native forests
  • Hybridize with 6 native congeners
  • Leads to extinction by loss of gene pool
• Golden-headed lion tamarin
  • Listed by IUCN as endangered species in Bahia state
  • Survival depended on captive breeding program started by a veterinarian
  • After his death - Captives released into local municipal park in Rio de Janeiro State
  • Now, native congener threatened with extinction
  • Compete for resources and hybridize with native congener - Weakening gene pool
• Rock cavy
  • Introduced on the island of Fernando do Noronha in the 1960s as wild game for military
  • Feeds on fruits, seeds, and roots
  • Destroys entire bushes or trees by gnawing at base
  • Exposes soil to erosion and/or establishment of invasive plants

Pooled Vertebrate Effects, Economic Impacts, and Summary

Pooled Vertebrate Effects

• Only ~2% of Brazil’s vertebrates invasive
• Lack of good data
  • Population sizes
  • Distribution
  • Effects on native organisms
• Invasive species documented in all states
  • Invasive species highest in states of eastern Brazil
• Most vertebrate invasions result from - Intentional introductions, watershed alterations, or adventive occurrences

Economic Impacts

• To date, no comprehensive economic estimates of invasive species impacts in Brazil
• Ecosystem damage caused often exceeds economic benefit
• Invasive species often harbor/vector human and animal diseases
  • Increases health care costs

Summary

• Development of strategies for coping with invasive species problems crucial
• Development of action plan
  • Identification, monitoring, eradication, and control
  • Strict control of alien species entering country
• Governmental regulations for propagation
• Investment in research
  • Mapping and distribution studies
  • Develop eradication techniques
  • Economic analyses

Module 9

Invasive Plants on the Indian Subcontinent

Introduction

• Frequency of plant invasions accelerated and human-driven
• In practice, hardly any barriers to prevent plant invasions
• Plants moved from one region to another
  • Food, medicine, timber, furniture, ornament
  • Demand for international trade in plants
• Two examples native to tropical America
  • Lantana camara - Intentionally moved for ornamental value
  • Parthenium hysterophorus - Human-aided unintentional introduction
• Climate change, habitat disturbance exacerbate problem
• Alien plants threaten native ecosystems
  • Alter plant communities
  • Reduce biodiversity
  • Change soil structure
  • Impact human health
• Invasive plants adaptable and undergo genetic changes from selection pressure
• Invasive plants: Ecological and economic impacts
  • Species and communities
    • Species composition
    • Community composition
    • Abundance
    • Habitat structure
    • Rare and threatened species
    • Hybridization
  • Ecosystem properties
    • Fire
    • Alternative states
  • Biogeochemistry
    • Nutrient cycling and mineralization
    • Detritus
    • System drivers
    • pH
    • Geomorphology
  • Ecosystem services (Social - Ecological)
    • Water: Quality, quantity, retention, floods
    • Wood
    • Tourism and wilderness
    • Other resources
  • Economic impacts
    • Direct economic loss
    • Costs of control

Indian Subcontinent and Plant Invasion

• India, Bangladesh, Sri Lanka, Nepal, Bhutan, and the Island of Maldives
• Largely tropical with diverse flora and fauna
  • 3 major regions of biodiversity - Himalayas, western ghats, Indo-Burma region
  • Great diversity of ecosystems and habitats - Grasslands, forests, wetlands, aquatic, and marine
• ~18% of flora alien, ~50% new world origin - In total, 173 invasive alien species, 117 genera, 44 families
• Origin - Tropical America, Africa, and Europe
• Several terrestrial and aquatic plants - Highly invasive and impact native ecosystems

Pathways of Invasion

• Globalization - Increased trade and travel
  • 2nd most populated country
  • Recent rapid economic development
• 3 general pathways
  • Importation of commodities
  • Arraival of transport vector (via humans)
  • Natural spread from adjacent regions
• Other pathways
  • Ship ballast
  • Crop seed contaminants
  • Carried by humans/animals
  • Intentional introductions
  • Contaminated machinery

Prominent Invasive Plants

• ~55 alien plants identified
• Represent all plant forms
  • Herbs, shrubs, trees, grasses, vines, and aquatic plants
• Most native to tropical America
• Primarily members of the Asteraceae
• Several species - Widespread and create problems
  • Giant reed, Arundo donax

Parthenium hysterophorus

• Entered India in contaminated cereal grains imported from U.S.
• Colonizes wide habitats and forms huge monocultures
• Invaded almost every Indian state
• Impacts
  • Reduces native plant diversity
  • Major cause of fodder famine
  • Toxic to livestock
  • Causes respiratory problems in humans
• Recognized as biological pollutant
  • Health problems in humans and livestock

Ageratum conyzoides

• Billy goat weed
• Introduced in 1860s as ornamental
• One of the worst invaders of agricultural lands
• Invasive properties
  • Fast growth rate
  • Vegetative reproduction via stolons
  • Produces numerous seeds
  • Allelopathic

Chromolaena odorata

• One of top 100 species listed by GSID
• Introduced as ornamental in 1940s
• Interferes with crop production in Northeastern India

Lantana Camara

• One of top 100 species listed by GSID
• Introduced to India in early 19th century as ornamental
• Rapidly spreading into high altitudes - Especially Himalayas
• Invades variety of habitats - Forests, grasslands, agricultural fields, urban, and protected areas
• Strongly allelopathic and interferes with growth of various native plants

Mile-A-Minute Weed

• Creeping vine that smothers native vegetation
  • Discovered in south Florida in November 2009
• Intentionally introduced to India
  • Camouflage for airfields during WWII

Aquatic Weeds

• Water hyacinth, salvinia, alligator weed, water spinach
  • Invaders of freshwater ecosystems and wetlands
  • Water hyacinth, salvinia, and alligator weed native to South America

Invasive Trees and Shrubs

• Lead tree (Leucaena leucocephala)
  • Leguminous shrubs introduced to India for agroforestry
  • Form dense monocultures
  • Enormous seed production
• Mesquite (Prosopis juliflora)
  • Introduced to India for afforestation
  • Prolific seed producer
  • Form dense monocultures

Prominent Invasive Plants

• Several species purposely introduced
  • Ornamental value
  • Essential oils
  • Timber production
  • Medicinal purposes
• Chinese tallow (Triadiaca sebiferum)
  • Native to China
  • Spreading rapidly in the Himalayan region
  • Listed by GSID as serious invader

Environmental Impacts

• Fast growth and rapid spread of alien plants alter ecosystem structure and function
  • Nutrient cycling and fire regimes
• Little data in India to support ecosystem impacts
• Three examples from NW Himalayas
  • Lantana, Parthenium, billy goat weed
• Jatropha
  • Newly introduced biodiesel production major threat to agriculture and livestock
  • Highly toxic to humans and livestock

Economic Harm

• Alien plants contribute to losses in agricultural production and control costs
• Market and non-market impacts
• Losses from Lantana - US$924 million
• Economic costs higher - Environmental impacts
  • Habitat damage
  • Loss of threatened and endangered species
  • Extinctions
  • Loss of ecosystem services
• Very few published studies quantifying economic costs of invasive plants

Future Outlook

• Several weeds widely established
• Others emerging as new problems
• Indian government - Developing new control and regulatory measure for excluding new species
  • Preparing national databases
  • Raising awareness of invasive species problem
  • Determining pathways of invasion
  • Coordinating efforts of government and NGOs for early detection
  • Following international standards for excluding potential invaders

Alien Plant Pathogens in India

Introduction

• >70% of India’s human population - Agriculture/agriculturally based professions
• Plant diseases - Impact people and animals
  • Modify habits, affect standard of living, impact India’s economy
• India’s famines - Crop diseases caused by introduced pathogens
  • 1943 Bengal famine most devastating
  • Caused by rice blight fungus
  • >2 million humans died of starvation
• Plant pathogens - Introduced with seeds and propagation materials
• Some regulatory measures adopted to avoid introduction
  • 1914 - Destructive Insect and Pest (DIP) Act
  • Intended to prevent and eradicate alien diseases
  • 1930 - 1956 - DIP Act revised 8 times
  • 1914 and after - 13 diseases introduced

India’s Key Plant Pathogens

Plant Pathogens

• Impacts
  • ~74% of crop plant pathogens introduced
    • Hitchhikers on seeds and other plant propagation materials
  • Economic loss from pathogens - $2 billion

Fungal Pathogens - Potato Late Blight

• One of the worst potato diseases worldwide
  • 1845 - Potato famine, Ireland
• First observed in 1870, then in 1883
  • Carried on potatoes imported by Europeans
• Can cause ~70% reduction in susceptible potato varieties
• Epiphytotics common in Punjab
  • Weather conditions conducive to disease outbreaks
  • Tuber yield reduced by 15% - 100%
• Disease still prevalent in Tamil Nadu state

Fungal Pathogens - Potato Wart

• Thought to be native to South America
• Also known as black wart, black scab, potato canker, and cauliflower disease
• 2nd most important potato disease
• 1952 - First reported on imported potato variety (furose) in Darjeeling, West Bengal
• Steps to eradicate disease (burning crops and chemical disinfection of soil) failed
• 1958 - ~50% of potato-growing area invaded
• 1959 - Ban on potato movement from West Bengal

Fungal Pathogens - Wheat Flag Smut

• Disease prevalent in wheat-growing regions worldwide
• 1868 - First identified in Australia
• 1918 - First reported from West Punjab (Pakistan), probably introduced from Australia
• Disease not widespread but important
• Persistent and under suitable conditions, disease becomes virulent
• Impacts - Reduced yield to crop failure
• Disease incidence up to 75% in northern India

Fungal Pathogens - Rice Brown Leaf Spot

• Disease prevalent in rice growing areas along the East coast subjected to monsoons
• Causes enormous losses
• 1919 - First reported from Madras (Chennai)
• Prevalent in all rice-growing areas
• Major epidemics
  • 1943 - West Benhal had 90% yield losses
  • Most devastating epiphytotic ever recorded
  • Current yield losses range from 22,000 - 28,000 tons

Fungal Pathogens - Rice Blast

• Disease occurs worldwide ever since rice cultivated
• Earliest records from China, Japan, Italy
• Globally, considered most important rice disease due to huge yield losses
• 1913 - First reported in India
• 1919 - Major epidemic in Tamil Nadu
• Disease prevalent in coastal areas and upland rice most susceptible
• 1960 - Disease became insignificant in Northern India after introduction of semi-dwarf, high-yielding varieties

Fungal Pathogens - Sunflower Downy Mildew

• Introduced in India and other countries via seed trade
• Most important constraint to sunflower production
• 1984 - First detected in 1984
• Seedborne, soilborne, and airborne - Difficult to eradicate after establishment

Fungal Pathogens - Maize Downy Mildew

• 1967 - First reported
• In total, 9 different Sclerophthora spp.
• 5 species cause economic losses in SE Asia
• Disease caused by S. Rayssiae var. Zeae restricted to India

Fungal Pathogens - Tobacco Black Shank

• First detected in Dutch East Indies
• 1938 - Introduced
• Sporadically infects all types of tobacco grown under high rainfall or irrigated conditions
• Disease first appears on lower leaves during rain season

Bacterial Pathogens - Rice Bacterial Blight

• First reported from Philippines ~60 years ago
• Minor disease until 1950 when it impacted rice production in Japan
• First reported in India in 1951
• Disease most commonly affects foliage
• Major hurdle to increasing rice cultivation
• Crop losses can reach 50%

Viral Pathogens - Banana Bunch Top Virus

• Introduced from Sri Lanka ~1940
• Invaded large area
  • Initially southern tip of India (Kerala)
  • Spread northward along east coast (Assam)
  • Virus restricted to this region

Viral Pathogens - Cotton Leaf Curl Virus

• Discovered in 1994 northwest region
  • Punjab and Rajasthan
• Introduced from Pakistan
• At least 2 alternative hosts
  • Indian mallow, Abutilon indicum (L.) Sweet
• Disease widespread throughout cotton growing region - Vectored by whiteflies
• Managed by planting resistant varieties

Viral Pathogens - Peanut Stripe Virus

• Seed-borne virus of quarantine importance
• Imported from China
• Responsible for significant crop losses
• Alternate hosts include soybean and cowpeas
• Vectored by an aphid, a sucking insect

Nematode Pathogens - Potato Cyst Nematode

• Golden nematode
• Important potato pest worldwide
• 1961 - First detected in southern India
• Apparently introduced from Britain in tubers and weed hosts
• Confined to potato growing region in Southern tip of India

Summary

• India is an agriculture-based country
• 5 - 10% crop losses attributed to introduced diseases
• Ministry of Agriculture formulated new policies for intercepting new diseases to prevent introduction/establishment

Module 10

Introduction

• Human activities promote intentional or accidental spread of invertebrates
  • Agriculture
  • Forestry
  • Transporation
• 3 criteria for invasive species
  • Must be introduced
  • Must establish viable populations
  • Cause economic or environmental harm
• 2 famous examples of invertebrate Indian introductions (biocontrol agents):
  • Prickly pear cactus - Cochineal scale
  • Cottony cusion scale - Beetle and fly
• Laid foundation for promoting interaction of invasive species
• Increased globalization leads to introduction of alien invertebrates into vulnerable agriculture and natural areas, increasing
• Climate leads to increased importance in limiting invasive species distributions
• Invasive species establishment occurs when
  • Climate suitable
  • Sufficient nutrients
  • Opportunities for reproduction
• Alien invertebrates considered top 2 or 3 forces driving other species to extinction
• Cause negative impacts to
  • Human health
  • Economy
  • Biodiversity
  • Ecosystems

Economic Implications

• Without biocontrols, invasive species populations increase to damaging levels
• Susceptible habitat characteristics
  • Provide food and climate like invader’s native range
  • Characterized by disturbance (ruderal)
  • Those with less biotic resistance factors
  • Islands with fewer species
• Examples
  • Luprops beetle in rubber plantations of Wester Ghats and northeaster India
  • Invasions predicted by tracking leaf drop phenology

Economic Impacts - Examples

• Eucalyptus plantations invaded by gall-forming wasp from Australia
  • Gall impacts tree species with long-rotation cycles
  • Problem exacerbated by transporting infected seedlings to new areas
• Coconut eriophyid mites introduced in 1990s
  • Gall-forming pest
• Coconut hispine beetle, a new pest
• Cotton mealybug
  • Impacts cotton and other crops and ornamentals
• Papaya mealy bug, discovered 2008
  • Wide host range
• Coral tree gall wasp, discovered in 2004
  • Attacks ornamental and shade coral trees
  • Provides support for black pepper vines
  • High infestations cause tree mortality
• Golden apple snail
  • Native to Brazil
  • Invades rice paddies
  • Intermediate host for parasitic nematode
  • Causes EME in humans
• Emerging rice pests
  • Rice water weevil is native to US and Canada
  • Rice black bug
  • Rice panicle

Economic Impacts - Important Agricultural Pests

• Leucaena psyllid, whiteflies, coffee berry borer
• Capable of migrating long distances
• Ecological and intrinsic factors influencing crop pest distributions
  • Climate, soil, host plants, vectors, natural enemies, competition, genetic adaptability, and reproductive plasticity
• Bemisia Type B whitefly
  • Attacks over 900 host plants
  • Transmits over 10 plant viruses
• Serpentine leaf miner
  • Introduced 1990
  • Attacks over 100 hosts
  • Pest of vegetables, castor bean, and ornamentals
• Green and brown leafhoppers
  • Migrate long distances
  • Invade virtually all suitable habitats
• Cashew thrips
  • Native to South America
  • Pest of cashew and mango
• Giant snail
  • Worst pest of agricultural crops

Summary

• Invasive species important in structuring natural communities
• Invertebrates threaten ecological communities and global biodiversity
• Ecologist Donald Strong, biological control may be the only option for pests of grave environmental concern

UF/IFAS Weed Risk Assessment

How to Complete

• Collect as much data as possible before answering any questions
• BEWARE THE GOOGLE-HOLE!!!!
• Start with website searches
• Search Google up to 10 pages deep (5 is usually enough)
• Search journal articles with Web of Science and/or Google Scholar
• Open Excel
  • Click ignore links
• NOTHING EVER GOES IN COLUMN D
• Answer questions in column C
  • Y
  • N
  • UNK
• Score will automatically appear in Column D
• Give citations in “Reference”
  • Provide date you accessed websites
• Put supporting data in “Source data” column
  • Try to avoid direct quotes, summarize the data and put in your own words

Module 11

Economic Consequences of Environmental Impacts of Alien Plant Invasions in South Africa

Introduction

• ~9,000 plants introduced in South Africa
  • Crops, timber and firewood, ornamentals, sand stabilization, and barrier/hedge plants
  • ~750 trees, 800 shrubs, succulents, and herbs
• ~1,000 naturalized and ~200 invasive
  • 161 plants (110 woody, 13 succulent, 38 herbaceous) highly invasive
• Concern about biodiversity conservation
  • ~17,000 endemic vascular plants
• Contributing factors
  • 350-year long colonial history
  • Well-developed infrastructure
  • Thriving agriculture and forestry sectors
• Until recently, emphasis on the history, ecology and management of invasive plants
  • Little interest in economic aspects and invasion consequences
• Important milestone - Current and potential impacts on water resources
  • Demonstrated economic benefits of intervention
  • Establishment of a ‘working for water’ program emphasized control of alien plants to protect water
  • Current and future water supplies
  • Invested > $657 million from 1995 - 2009

Extent of Problem - Surveys in 1996 - 1997 to Map Invasive Plants

• ~10 million ha (1 ha = 2.47 acres) invaded by ~180 species
• Western Cape’s most invaded region
• Invasions concentrated in wetland regions
  • Fynbos biome (Mediterranean-type shrubland) most invaded area, mainly acacia, hakea, and minus species
  • Forest, grassland, and savanna biomes also heavily invaded
  • Riparian systems invaded by syringa and jacaranda trees
  • Nama karoo (semi-desert shrubland) invaded by mesquite, cactus, saltbush species
  • Aquatic weed species include water hyacinth, water lettuce, Kariba weed, parrot’s feather, red water fern, and hydrilla
  • Only water hyacinth and hydrilla not effectively controlled biologically

Environmental Impacts

• Most analyses anecdotal or correlative
  • Comparing invaded with uninvaded sites or one site over time
  • Few detailed studies, no manipulative experiments
• Chapin et al. (1996) invader categories
  • Discrete-trait invaders (DTIS) - Add new function, e.g., N fixation, alleopathy
  • Continuous-trait invaders (CTIS) - Differ only in traits (e.g., growth rates, litter quality) distributed among species
  • Generally, greater ecosystem-level impacts from DTIS

Environmental Impacts - Most dramatic impacts in South Africa from DTIS

• Nitrogen fixing acacia trees altered nutrient cycling regimes in Fynbos
• Added new life form in a treeless region
• Caused ecosystem-level changes in
  • Biomass distribution
  • Plant density and height
  • Leaf area index
  • Litter fall and decomposition rates in stream flow
  • Use ~10% of surface water runoff
• Threaten endangered plant species and altered bird distributions
  • Other DTIS having major ecosystem impacts
  • Chromolaena, schinus molle, prosopis

Environmental Impacts - DTI impacts in South Africa not only terrestrial

• Aquatic invaders grow rapidly, forming dense mats
  • Examples: Water hyacinth and red water fern
• Negative impacts include
  • Water loss via evotranspiration
  • Oxygen depletion
  • Reducing potable water quality and quantity
  • Impeding navigation, blocking flood control structures and collapsing bridges
  • Clogging irrigation and hydropower pumps
  • Limiting access for recreation and fisheries
  • Decreasing property values
  • Mosquito breeding

Environmental Impacts

• Positive impacts - Water hyacinth
  • Feed for livestock
  • Mulch for crop production
  • Fiber for paper and weaving baskets
  • Biological filtration/nutrient removal
• Drawbacks
  • Plant contains 96% water
  • Harvesting expensive
  • Promoting utilization leads to further spread

Economic Impacts - Cause of alien plant invasions

• Unintended consequence of economic activity
  • Globalization of world economy
  • Liberal trade laws and regulations
• Human behavior primary driver of plant invasions
• Facilitates establishment and spread
  • Modern transportation, promoting trade of goods
  • Large-scale conversion of natural vegetation (disturbance)
• Plant invasion tied to economics and ecology
• Credible economic assessments involve both market and non-market impacts
• Results must enable decision-makers to make the right decisions

Economic Impacts - Key elements for invasive plant control

• Institutional regulation of human behavior
• Appropriate policies and strategies
• Complications and challenges
  • Difficulty quantifying invasions in economic terms
  • Tendency to avoid problem until crisis occurs
  • Conflict of interest species - beneficial and deleterious impacts
  • Variability of net economic impact estimates - Scale, scope, timing, and approach
  • Public good issue - Control measures under applied

Approaches to Economic Evaluation

• Invasive plants have both positive and negative impacts
• Need to identify who’s affected and whether effects are positive or negative
• In the 1990s, invasive woody plant impacts - Quantified in terms of effects on water resources
  • Persuaded government to take the problem seriously
  • Water in South Africa limiting factor
• Most studies report positive return on investment, especially role of biocontrol research
• Acacia industry - US$1.4 billion in water loss vs. less value of wood chips, etc
• Studies show invasive plant control makes economic sense
• Most benefits derived from curtailing spread, reducing densities, and mitigating future impacts
• Challenge for “conflicting interest” species
  • Mesquite, positive and negative impacts - Loss of groundwater vs. livestock fodder, shade, shelter, and biofuel

Approaches to Economic Evaluation - Framework for Mathematical Model

• PVC = DBC - DCC + PEoBC - NEoBC
• PVC = Present Value of Integrated Control
• DBC = Present Value of Direct Benefits of Control
• DCC = Direct Costs of Invasive Plant Control
• PEoBC = Present Value of + Control Externalities
• NEoBC = Present Value of - Control Externalities

National Scale Assessment

• Alien plants degrade rangelands
  • Replace palatable with unpalatable species
  • Restrict access by livestock and ranchers
• Livestock carrying capacity decreased by 123 K LSU
• Invasive plant cost summaries
  • Water-related losses - US$773 million
  • Livestock grazing losses - US$45 million
  • Biodiversity losses - US$57 million
  • Total - US$867 million

Dealing with the Problem - Working for Water program

• Invasive plant control and social development
  • Employs poorest people in communities nearest to alien plant infestations
  • Increased income and nutrition
  • Provided better clothing
  • Increased educational opportunities
  • Provided small business training
  • Procurement of protective clothing, tools, and equipment
  • Raised public awareness
• Social development program
  • Child-care program for working women
  • HIV/AIDS awareness campaign
  • Prisoner release rehabilitation

Perscription for Success

• Actively manage invasive plant spread
• Use non-invasive species when possible, introduce biocontrol agents early on
  • Use biocontrol to limit seed production of otherwise invasive species
• Recognize potential invaders early and implement precautionary measures
• Educate public about dangers and invasive species costs
• Encourage use of non-invaders for ornamentals
  • “Alter-natives”

Case Study

• Economic Benefits of Red Water Fern Biocontrol
• Complete control in 2 years

Economic Advantages of Biocontrol

• Labor intensive clearing of invaders in the working for water program not sustainable
• Needed to develop program components to prevent reinvasion
• Biocontrol - One of the most cost-effective tactics for reducing invader impacts
  • Of 46 weed species, 22 under complete or sustantial biocontrol
  • Total cost for biocontrol from 1997-2000 - Only $3 million
  • Returns on investment unprecedented - 50:1 - lantana, caesalpinia, chromolaena - 3726:1 - Australian acacias
  • Including biocontrol as component of working for water program expected to reduce costs from $60 to $20 million per year - 67% cost reduction

Conclusions

• Alien plant invasions severe in South Africa and intervention programs justified
  • Reduced biodiversity
  • Changes in water flow
  • Genetic hybridization
  • Changes in fire regimes
  • Loss of grazing lands
  • Increase disease vectors
• Impacts pervasive and have important implications for humans and environment
• Unique aspect is ability to leverage further
  • Benefits from control programs
  • Funds for working for water program sourced from poverty relief budget
• Convincing economic assessments needed to maintain support
• Biocontrol offers considerable benefits, which significantly outweigh costs
  • Most cost-effective intervention
  • Subject of debate because introducing more alien species with some degree of risk

Alien Invertebrate Animals in South Africa

Introduction

• Compared to plants and animals, alien invertebrates are not well studied in South Africa
• ~56 insects introduced for biocontrol of weeds, >50% have documented impact
  • Impacts on non-targets not well studied
• Invasive invertebrates causing large-scale negative environmental and health impacts
  • Yet to invade South Africa, escaping notice, or not investigated
• Introduced crop pests receive considerable attention, $1 billion in losses
  • Red scale, Mediterranean fly, and codling moth

Mediterranean Fly

• Ceratitis capitata - One of the most economically costly pest species
• Spread from native Afrotropical range to main fruit-producing regions
• First confirmed presence in South Africa - Late 1800s
• Successful establishment
  • Polyphagous life-history
  • Short development time
  • High population reproductive potential
  • Broad climate niche
• Larvae and probing by adult females cause most damage
  • Fruit vulnerable to secondary infections by pathogens and pests
• Can lead to 100% crop losses

Argentine Ant

• Native to Argentina and Brazil
• Arrived ~1898 in cattle fodder
• Globally, invaded Bermuda, Mediterranean Europe, Southwest U.S., Chile, Western Australia, New Zealand, and Hawaiian Islands
• Established in Cape Peninsula
• Generally found in lower altitude sites and areas with established roads
• Not found in sites accessible only on foot

Argentine Ant - Environmental Impacts

• Displace native ants by aggressive behavior, chemical defense, abundance, and interference competition
• A few native species co-exist due to differences in foraging patterns, small body size, and stealth
• Disrupt mutualism by interfering with plants relying on native ants for seed dispersal (myrmecochory)
• Obligate Myrmecophilous lycaenid butterfly caterpillars at risk
• Impact fynbos by affecting pollination
• Impacts on ground inhabiting insects unknown

Argentine Ant - Agricultural and Household Impacts

• Attracted to honeydew produced by Hemiptera
  • Mealybugs, scale insects, and aphids
• Protect pest Hemiptera from natural impacts
• High densities in citrus and guava
• Presence of ants deters pollinators
• Beehives attacked and destroyed
• Outcompete bees for nectar by nocturnal activity
• Invade homes to forage for food and water

Varroa Mite

• Most serious 20th century bee pest
• Spread from Asia, benign on natural host Apis cerana
• A. Mellifera unable to tolerate ectoparasite
  • Capable of killing entire honeybee colony
• Unique life cycle adaptations
  • Fertile female invades uncapped cell and feeds on bee larva
  • First egg is male, remainder female
  • Male mates with sisters and dies
  • Mother and daughters emerge with bee
  • Drone (male) brood preferred over workers
• Spread between colonies by flight

Varroa Mite - Environmental and Agricultural Impacts

• Brood death and developmental abnormalities
• Virus also implicated in colony death
• Wild bee populations in Europe and US - Mite mortality
• May be less virulent to African honeybees
  • Shorter post-cell capping developmental period - Limits mite reproduction
  • African bees exhibit defensive behavior
  • Less damaging under tropical conditions in South Africa
• Greatest impact on wild bee populations
  • Implications for biodiversity
  • Loss of plant species - Affects herbivores
  • No natural enemies for mite

Varroa Mite - Economic Impacts

• So far, extremely damaging to colonies
  • Loss of pollination to commercial crops and associated job losses
• Beekeeping will become difficult and expensive
• Reduction in colonies and wild bees available to commercial beekeepers
• Major impact on small-scale rural beekeeping

Spotted Stem Borer

• Chilo pertellus
• Native to Asia and India subcontinent
• First discovered in South Africa in 1958 after invading African continent in 1932
• Dominant in humid, coaster regions
• Recently, higher-altitude grain growing areas
• Displacing Busseola fusca

Spotted Stem Borer - Agricultural Impacts from Native and Introduced Stalk Borers

• Major pest of cereal crops
  • Maize and grain sorghum
• Bivoltine (2+ generations) during summer periods
• Cereal crop losses between 10-100%

Spotted Stem Borer - Economic Impacts

• 44th out of 101 most important crop pests
• 7th most important lepidopteran pest
• High yield losses and control costs
  • Insecticide costs - $2.5 to $7 million
  • Effective only against first instar (exposed)
• High cost and limited effectiveness of pesticides led to the adoption of alternative methods
  • Culturla control - Tillage control, interplanting with Napier grass (trap crop) - Reduction in maize (89%) and sorghum (94%)
  • Biological control with parasitoids - None established, ineffective

Red Scale

• Native to Central Asia and India
• Major pest of citrus
• Introduced > 100 years ago
• Life cycle
  • Female lives under a circular, reddish-brown covering
  • First instars (crawlers) leave covering and infest fruits, leaves, twigs, and branches
  • Become sessile
  • Up to 3 generations annually

Red Scale - Agricultural Impacts

• Globally, most important pest in terms of control costs and research
• Attack various fruits and ornamentals heavy infestations on citrus and roses
• Losses based on severity
  • Light infestation - Rejection of fruit for export
  • Moderate - Fruit rejection, leaf and fruit drop
  • Heavy - Unsalable fruit, defoliation and death
• Infestations tied to history of insecticide use
  • Sprayed with organophosphates (OPS) in 1948
  • Developed resistance to OPS in 1974
  • OPS replaced with oils, natural enemy resurgence
  • Current IPM systems effective

Red Scale - Economic Impacts

• Damage peaked with OPS resistance and absence of natural enemies
• Demand for blemish-free fruit high, small-scale infestations not tolerated
• During 1966 - 1967, red scale caused 50% of the 25% of fruit crops not acceptable for export
• During same time, cost of chemical control on citrus grove - $1 million
• Switch to IPM
  • 6X reduction in spray costs
  • Doubled the amount of exported fruit OPS replaced with oils, natural enemy resurgence

Snail Pests

• Two invasive species from North America introduced via aquarium trade
• Widespread occurrence in rivers and catchments, especially near urban centers
• Life history attributes conducive to invaders
  • Tolerate wide range of temperatures of aquatic habitats - Mud and vegetation, rivers, streams, lakes, and containers
  • One species capable of self-fertilization
  • Colonization of disturbed habitats
  • High dispersal and reproductive rates
  • Short generation times
  • Low susceptibility to predators

Snail Pests - Environmental and Economic Impacts

• Info on ecological impacts lacking
  • Predation on at least one native snail
• Threaten health of livestock and wild ungulates
  • Intermediate hosts for two liver fluke species
  • Ability to survive out of water may increase transmission to fluke to definitive host (cattle) - Parasite encysts on forage grass
• Economic impact to small farmers high
• One species intermediate host of rat lung nematode - Causes human meningitis

Mediterranean Mussel

• Most widespread, successful marine alien
• Probably introduced in 1970s by humans
• Early 1990s, spread as far East as Port Alfred
• Dominant intertidal organism along the entire West Coast
• Biomass ~194 tons/km

Mediterranean Mussel - Ecological Impacts

• Rapid growth, high reproduction, and tolerance to desiccation
• Three major impacts
  • Compete for substrate space - Displace native species
  • Provision habitat for other species - Support denser invertebrate fauna
  • Increase food for predators - Oystercatcher birds switched diet away from limpets

Mediterranean Mussel - Economic Impacts

• Fouling of ships’ hulls and intakes
  • Mechanical removal - Mussel beds established on mudflates
• Mariculture industry within Salanha Bay
  • 2,145 tons
  • $3.5 million
• Benefit likely outweighs cost

Summary

• Range of realized and potential impacts
• Human activities - Dispersal and spread of invertebrates
• New invaders - Affect environmental and economic interests
• Argentine ant and varroa mite - Global threat to world’s rarest plant biome
• Mussel introduction - Positive economic impact

Module 12

Invasive Vertebrates of South Africa

Introduction

• Ecotourism South Africa’s newest economic growth factor
• Important to preserve protected areas and landscapes
• Benefits of maintaining biodiversity
  • Ecological services
  • Harvesting game
  • Aesthetic and cultural values
• Challenge - Establishing balance between economic development and conservation policies
• Introducing potentially invasive vertebrates alters valuable environments
  • E.g., human introduction of ungulates for food and sport
• Introduction of 21 invasive fish species
  • Profound on aquatic ecosystems
  • Extinction of native fish, amphibians, and invertebrates, but alien fish - Drivers of economically important fisheries industry
• Implementation of laws restricting importation and movement must balance trade-offs between economic gain and biodiversity loss
• Understanding kep factors of invasion biology crucial - e.g., dispersal ecology
• No consistent pattern for introductions
  • Despite freshwater hot-spot, no marine fish
  • Number of alien bird, reptile, and amphibian species intermediate to low, perhaps merely undetected
  • “Absence of evidence not evidence of absence”
• Number of introduced mammals high but number of invasive species low
• Alien bird establishment on islands not > mainland
  • Runs counter to island biogeography theory
• Evidence-based evaluation of each major taxon regarding environmental, agricultural, and economic impacts
• Consideration for new research directions
• General examination of legislation governing alien species importation and movement
• Extralimital: Invasion by indigenous species outside native range but within given geopolitical boundary

Freshwater Fishes

Freshwater Fishes

• South Africa hot spot for alien fish invasions
• Started in early 18th century with goldfish for ornamental purposes
• Currently, 24 alien and 19 native species introduced in South Africa’s water bodies
  • 21 species documented as invasive (~ 49%)
• Humans responsible for introduction and spread
  • Propagation occurred at state-funded hatchery in Cape region
  • Distributed to other provincial hatcheries via formal stocking programs
• Reasons for Introductions
  • Angling or fishing
  • Biocontrol programs
  • Pet trade
  • Unintentional extralimital movement via inter-basin water transfers
• Angling
  • Introductions during late 19th and early 20th centuries focused on recreational angling
  • Rainbow and brown trout
    • Successful establishment in cool, clear oxygen-rich waters in high-altitude or temperature areas
  • Common carp and trench-coarse fish
    • Stocked in warmer, lowland rivers

Angling

• Demand for predatory species caught with lures
• Large-mouth bass
  • Warm slow lentic/lotic water
• Small-mouth bass
  • Cooler lentic/lotic water
• Spotted bass
  • Turbid and flood waters
• Bluegill sunfish
  • Predator and food for bass
• Banded and Mozambique tilapia
  • Extralimital food for bass

Biological Control

• Several species distributed from fish hatcheries for mosquito control in 1930s - 1940s
  • Mosquitofish, guppy, and goldfish
• Feral guppy and goldfish populations - limited to urban streams and reservoirs
• Mosquitofish widely distributed
  • ~ 50 of South Africa’s river systems
• Asian grass carp - introduced into farm dams for aquatic weed control
  • Diploid carp widely established in river systems
  • Considered a pest in Vaal River due to high densities

Aquaculture

• Escape from aquaculture operations resulted in 4 species invasions
  • Rainbow trout
  • Common carp
  • Nile tilapia
  • Silver carp
• Silver carp imported from Israel in 1975, thought unable to spawn
  • Viable populations in Olifants-Limpopo River system

Ornamental Fish Trade

• Aquarists likely responsible for unwanted release of 4 species in South African lakes and streams
  • Feral guppy
  • Swordtail
  • Goldfish
  • Armored catfish

Inter-Basin Water Transfers (IBTs)

• Establishment of Orange River (OR)
• Fishes in Sundays and Great Fish Rivers
  • Orange/Great Fish River IBT scheme completed in 1975
  • 82 km tunnel
• Facilitated transfer of smallmouth yellowfish, mudfish, and sharptooth catfish

Extent of Problem

• Alien (17%) and extralimital (71%)

Module 9

Invasive Plants on the Indian Subcontinent

Introduction

• Frequency of plant invasions accelerated and human-driven
• In practice, hardly any barriers to prevent plant invasions
• Plants moved from one region to another
  • Food, medicine, timber, furniture, ornament
  • Demand for international trade in plants
• Two examples native to tropical America
  • Lantana camara - Intentionally moved for ornamental value
  • Parthenium hysterophorus - Human-aided unintentional introduction
• Climate change, habitat disturbance exacerbate problem
• Alien plants threaten native ecosystems
  • Alter plant communities
  • Reduce biodiversity
  • Change soil structure
  • Impact human health
• Invasive plants adaptable and undergo genetic changes from selection pressure
• Invasive plants: Ecological and economic impacts
  • Species and communities
    • Species composition
    • Community composition
    • Abundance
    • Habitat structure
    • Rare and threatened species
    • Hybridization
  • Ecosystem properties
    • Fire
    • Alternative states
  • Biogeochemistry
    • Nutrient cycling and mineralization
    • Detritus
    • System drivers
    • pH
    • Geomorphology
  • Ecosystem services (Social - Ecological)
    • Water: Quality, quantity, retention, floods
    • Wood
    • Tourism and wilderness
    • Other resources
  • Economic impacts
    • Direct economic loss
    • Costs of control

Indian Subcontinent and Plant Invasion

• India, Bangladesh, Sri Lanka, Nepal, Bhutan, and the Island of Maldives
• Largely tropical with diverse flora and fauna
  • 3 major regions of biodiversity - Himalayas, western ghats, Indo-Burma region
  • Great diversity of ecosystems and habitats - Grasslands, forests, wetlands, aquatic, and marine
• ~18% of flora alien, ~50% new world origin - In total, 173 invasive alien species, 117 genera, 44 families
• Origin - Tropical America, Africa, and Europe
• Several terrestrial and aquatic plants - Highly invasive and impact native ecosystems

Pathways of Invasion

• Globalization - Increased trade and travel
  • 2nd most populated country
  • Recent rapid economic development
• 3 general pathways
  • Importation of commodities
  • Arraival of transport vector (via humans)
  • Natural spread from adjacent regions
• Other pathways
  • Ship ballast
  • Crop seed contaminants
  • Carried by humans/animals
  • Intentional introductions
  • Contaminated machinery

Prominent Invasive Plants

• ~55 alien plants identified
• Represent all plant forms
  • Herbs, shrubs, trees, grasses, vines, and aquatic plants
• Most native to tropical America
• Primarily members of the Asteraceae
• Several species - Widespread and create problems
  • Giant reed, Arundo donax

Parthenium hysterophorus

• Entered India in contaminated cereal grains imported from U.S.
• Colonizes wide habitats and forms huge monocultures
• Invaded almost every Indian state
• Impacts
  • Reduces native plant diversity
  • Major cause of fodder famine
  • Toxic to livestock
  • Causes respiratory problems in humans
• Recognized as biological pollutant
  • Health problems in humans and livestock

Ageratum conyzoides

• Billy goat weed
• Introduced in 1860s as ornamental
• One of the worst invaders of agricultural lands
• Invasive properties
  • Fast growth rate
  • Vegetative reproduction via stolons
  • Produces numerous seeds
  • Allelopathic

Chromolaena odorata

• One of top 100 species listed by GSID
• Introduced as ornamental in 1940s
• Interferes with crop production in Northeastern India

Lantana Camara

• One of top 100 species listed by GSID
• Introduced to India in early 19th century as ornamental
• Rapidly spreading into high altitudes - Especially Himalayas
• Invades variety of habitats - Forests, grasslands, agricultural fields, urban, and protected areas
• Strongly allelopathic and interferes with growth of various native plants

Mile-A-Minute Weed

• Creeping vine that smothers native vegetation
  • Discovered in south Florida in November 2009
• Intentionally introduced to India
  • Camouflage for airfields during WWII

Aquatic Weeds

• Water hyacinth, salvinia, alligator weed, water spinach
  • Invaders of freshwater ecosystems and wetlands
  • Water hyacinth, salvinia, and alligator weed native to South America

Invasive Trees and Shrubs

• Lead tree (Leucaena leucocephala)
  • Leguminous shrubs introduced to India for agroforestry
  • Form dense monocultures
  • Enormous seed production
• Mesquite (Prosopis juliflora)
  • Introduced to India for afforestation
  • Prolific seed producer
  • Form dense monocultures

Prominent Invasive Plants

• Several species purposely introduced
  • Ornamental value
  • Essential oils
  • Timber production
  • Medicinal purposes
• Chinese tallow (Triadiaca sebiferum)
  • Native to China
  • Spreading rapidly in the Himalayan region
  • Listed by GSID as serious invader

Environmental Impacts

• Fast growth and rapid spread of alien plants alter ecosystem structure and function
  • Nutrient cycling and fire regimes
• Little data in India to support ecosystem impacts
• Three examples from NW Himalayas
  • Lantana, Parthenium, billy goat weed
• Jatropha
  • Newly introduced biodiesel production major threat to agriculture and livestock
  • Highly toxic to humans and livestock

Economic Harm

• Alien plants contribute to losses in agricultural production and control costs
• Market and non-market impacts
• Losses from Lantana - US$924 million
• Economic costs higher - Environmental impacts
  • Habitat damage
  • Loss of threatened and endangered species
  • Extinctions
  • Loss of ecosystem services
• Very few published studies quantifying economic costs of invasive plants

Future Outlook

• Several weeds widely established
• Others emerging as new problems
• Indian government - Developing new control and regulatory measure for excluding new species
  • Preparing national databases
  • Raising awareness of invasive species problem
  • Determining pathways of invasion
  • Coordinating efforts of government and NGOs for early detection
  • Following international standards for excluding potential invaders

Alien Plant Pathogens in India

Introduction

• >70% of India’s human population - Agriculture/agriculturally based professions
• Plant diseases - Impact people and animals
  • Modify habits, affect standard of living, impact India’s economy
• India’s famines - Crop diseases caused by introduced pathogens
  • 1943 Bengal famine most devastating
  • Caused by rice blight fungus
  • >2 million humans died of starvation
• Plant pathogens - Introduced with seeds and propagation materials
• Some regulatory measures adopted to avoid introduction
  • 1914 - Destructive Insect and Pest (DIP) Act
  • Intended to prevent and eradicate alien diseases
  • 1930 - 1956 - DIP Act revised 8 times
  • 1914 and after - 13 diseases introduced

India’s Key Plant Pathogens

Plant Pathogens

• Impacts
  • ~74% of crop plant pathogens introduced
    • Hitchhikers on seeds and other plant propagation materials
  • Economic loss from pathogens - $2 billion

Fungal Pathogens - Potato Late Blight

• One of the worst potato diseases worldwide
  • 1845 - Potato famine, Ireland
• First observed in 1870, then in 1883
  • Carried on potatoes imported by Europeans
• Can cause ~70% reduction in susceptible potato varieties
• Epiphytotics common in Punjab
  • Weather conditions conducive to disease outbreaks
  • Tuber yield reduced by 15% - 100%
• Disease still prevalent in Tamil Nadu state

Fungal Pathogens - Potato Wart

• Thought to be native to South America
• Also known as black wart, black scab, potato canker, and cauliflower disease
• 2nd most important potato disease
• 1952 - First reported on imported potato variety (furose) in Darjeeling, West Bengal
• Steps to eradicate disease (burning crops and chemical disinfection of soil) failed
• 1958 - ~50% of potato-growing area invaded
• 1959 - Ban on potato movement from West Bengal

Fungal Pathogens - Wheat Flag Smut

• Disease prevalent in wheat-growing regions worldwide
• 1868 - First identified in Australia
• 1918 - First reported from West Punjab (Pakistan), probably introduced from Australia
• Disease not widespread but important
• Persistent and under suitable conditions, disease becomes virulent
• Impacts - Reduced yield to crop failure
• Disease incidence up to 75% in northern India

Fungal Pathogens - Rice Brown Leaf Spot

• Disease prevalent in rice growing areas along the East coast subjected to monsoons
• Causes enormous losses
• 1919 - First reported from Madras (Chennai)
• Prevalent in all rice-growing areas
• Major epidemics
  • 1943 - West Benhal had 90% yield losses
  • Most devastating epiphytotic ever recorded
  • Current yield losses range from 22,000 - 28,000 tons

Fungal Pathogens - Rice Blast

• Disease occurs worldwide ever since rice cultivated
• Earliest records from China, Japan, Italy
• Globally, considered most important rice disease due to huge yield losses
• 1913 - First reported in India
• 1919 - Major epidemic in Tamil Nadu
• Disease prevalent in coastal areas and upland rice most susceptible
• 1960 - Disease became insignificant in Northern India after introduction of semi-dwarf, high-yielding varieties

Fungal Pathogens - Sunflower Downy Mildew

• Introduced in India and other countries via seed trade
• Most important constraint to sunflower production
• 1984 - First detected in 1984
• Seedborne, soilborne, and airborne - Difficult to eradicate after establishment

Fungal Pathogens - Maize Downy Mildew

• 1967 - First reported
• In total, 9 different Sclerophthora spp.
• 5 species cause economic losses in SE Asia
• Disease caused by S. Rayssiae var. Zeae restricted to India

Fungal Pathogens - Tobacco Black Shank

• First detected in Dutch East Indies
• 1938 - Introduced
• Sporadically infects all types of tobacco grown under high rainfall or irrigated conditions
• Disease first appears on lower leaves during rain season

Bacterial Pathogens - Rice Bacterial Blight

• First reported from Philippines ~60 years ago
• Minor disease until 1950 when it impacted rice production in Japan
• First reported in India in 1951
• Disease most commonly affects foliage
• Major hurdle to increasing rice cultivation
• Crop losses can reach 50%

Viral Pathogens - Banana Bunch Top Virus

• Introduced from Sri Lanka ~1940
• Invaded large area
  • Initially southern tip of India (Kerala)
  • Spread northward along east coast (Assam)
  • Virus restricted to this region

Viral Pathogens - Cotton Leaf Curl Virus

• Discovered in 1994 northwest region
  • Punjab and Rajasthan
• Introduced from Pakistan
• At least 2 alternative hosts
  • Indian mallow, Abutilon indicum (L.) Sweet
• Disease widespread throughout cotton growing region - Vectored by whiteflies
• Managed by planting resistant varieties

Viral Pathogens - Peanut Stripe Virus

• Seed-borne virus of quarantine importance
• Imported from China
• Responsible for significant crop losses
• Alternate hosts include soybean and cowpeas
• Vectored by an aphid, a sucking insect

Nematode Pathogens - Potato Cyst Nematode

• Golden nematode
• Important potato pest worldwide
• 1961 - First detected in southern India
• Apparently introduced from Britain in tubers and weed hosts
• Confined to potato growing region in Southern tip of India

Summary

• India is an agriculture-based country
• 5 - 10% crop losses attributed to introduced diseases
• Ministry of Agriculture formulated new policies for intercepting new diseases to prevent introduction/establishment

Module 10

Introduction

• Human activities promote intentional or accidental spread of invertebrates
  • Agriculture
  • Forestry
  • Transporation
• 3 criteria for invasive species
  • Must be introduced
  • Must establish viable populations
  • Cause economic or environmental harm
• 2 famous examples of invertebrate Indian introductions (biocontrol agents):
  • Prickly pear cactus - Cochineal scale
  • Cottony cusion scale - Beetle and fly
• Laid foundation for promoting interaction of invasive species
• Increased globalization leads to introduction of alien invertebrates into vulnerable agriculture and natural areas, increasing
• Climate leads to increased importance in limiting invasive species distributions
• Invasive species establishment occurs when
  • Climate suitable
  • Sufficient nutrients
  • Opportunities for reproduction
• Alien invertebrates considered top 2 or 3 forces driving other species to extinction
• Cause negative impacts to
  • Human health
  • Economy
  • Biodiversity
  • Ecosystems

Economic Implications

• Without biocontrols, invasive species populations increase to damaging levels
• Susceptible habitat characteristics
  • Provide food and climate like invader’s native range
  • Characterized by disturbance (ruderal)
  • Those with less biotic resistance factors
  • Islands with fewer species
• Examples
  • Luprops beetle in rubber plantations of Wester Ghats and northeaster India
  • Invasions predicted by tracking leaf drop phenology

Economic Impacts - Examples

• Eucalyptus plantations invaded by gall-forming wasp from Australia
  • Gall impacts tree species with long-rotation cycles
  • Problem exacerbated by transporting infected seedlings to new areas
• Coconut eriophyid mites introduced in 1990s
  • Gall-forming pest
• Coconut hispine beetle, a new pest
• Cotton mealybug
  • Impacts cotton and other crops and ornamentals
• Papaya mealy bug, discovered 2008
  • Wide host range
• Coral tree gall wasp, discovered in 2004
  • Attacks ornamental and shade coral trees
  • Provides support for black pepper vines
  • High infestations cause tree mortality
• Golden apple snail
  • Native to Brazil
  • Invades rice paddies
  • Intermediate host for parasitic nematode
  • Causes EME in humans
• Emerging rice pests
  • Rice water weevil is native to US and Canada
  • Rice black bug
  • Rice panicle

Economic Impacts - Important Agricultural Pests

• Leucaena psyllid, whiteflies, coffee berry borer
• Capable of migrating long distances
• Ecological and intrinsic factors influencing crop pest distributions
  • Climate, soil, host plants, vectors, natural enemies, competition, genetic adaptability, and reproductive plasticity
• Bemisia Type B whitefly
  • Attacks over 900 host plants
  • Transmits over 10 plant viruses
• Serpentine leaf miner
  • Introduced 1990
  • Attacks over 100 hosts
  • Pest of vegetables, castor bean, and ornamentals
• Green and brown leafhoppers
  • Migrate long distances
  • Invade virtually all suitable habitats
• Cashew thrips
  • Native to South America
  • Pest of cashew and mango
• Giant snail
  • Worst pest of agricultural crops

Summary

• Invasive species important in structuring natural communities
• Invertebrates threaten ecological communities and global biodiversity
• Ecologist Donald Strong, biological control may be the only option for pests of grave environmental concern

UF/IFAS Weed Risk Assessment

How to Complete

• Collect as much data as possible before answering any questions
• BEWARE THE GOOGLE-HOLE!!!!
• Start with website searches
• Search Google up to 10 pages deep (5 is usually enough)
• Search journal articles with Web of Science and/or Google Scholar
• Open Excel
  • Click ignore links
• NOTHING EVER GOES IN COLUMN D
• Answer questions in column C
  • Y
  • N
  • UNK
• Score will automatically appear in Column D
• Give citations in “Reference”
  • Provide date you accessed websites
• Put supporting data in “Source data” column
  • Try to avoid direct quotes, summarize the data and put in your own words

Module 11

Economic Consequences of Environmental Impacts of Alien Plant Invasions in South Africa

Introduction

• ~9,000 plants introduced in South Africa
  • Crops, timber and firewood, ornamentals, sand stabilization, and barrier/hedge plants
  • ~750 trees, 800 shrubs, succulents, and herbs
• ~1,000 naturalized and ~200 invasive
  • 161 plants (110 woody, 13 succulent, 38 herbaceous) highly invasive
• Concern about biodiversity conservation
  • ~17,000 endemic vascular plants
• Contributing factors
  • 350-year long colonial history
  • Well-developed infrastructure
  • Thriving agriculture and forestry sectors
• Until recently, emphasis on the history, ecology and management of invasive plants
  • Little interest in economic aspects and invasion consequences
• Important milestone - Current and potential impacts on water resources
  • Demonstrated economic benefits of intervention
  • Establishment of a ‘working for water’ program emphasized control of alien plants to protect water
  • Current and future water supplies
  • Invested > $657 million from 1995 - 2009

Extent of Problem - Surveys in 1996 - 1997 to Map Invasive Plants

• ~10 million ha (1 ha = 2.47 acres) invaded by ~180 species
• Western Cape’s most invaded region
• Invasions concentrated in wetland regions
  • Fynbos biome (Mediterranean-type shrubland) most invaded area, mainly acacia, hakea, and minus species
  • Forest, grassland, and savanna biomes also heavily invaded
  • Riparian systems invaded by syringa and jacaranda trees
  • Nama karoo (semi-desert shrubland) invaded by mesquite, cactus, saltbush species
  • Aquatic weed species include water hyacinth, water lettuce, Kariba weed, parrot’s feather, red water fern, and hydrilla
  • Only water hyacinth and hydrilla not effectively controlled biologically

Environmental Impacts

• Most analyses anecdotal or correlative
  • Comparing invaded with uninvaded sites or one site over time
  • Few detailed studies, no manipulative experiments
• Chapin et al. (1996) invader categories
  • Discrete-trait invaders (DTIS) - Add new function, e.g., N fixation, alleopathy
  • Continuous-trait invaders (CTIS) - Differ only in traits (e.g., growth rates, litter quality) distributed among species
  • Generally, greater ecosystem-level impacts from DTIS

Environmental Impacts - Most dramatic impacts in South Africa from DTIS

• Nitrogen fixing acacia trees altered nutrient cycling regimes in Fynbos
• Added new life form in a treeless region
• Caused ecosystem-level changes in
  • Biomass distribution
  • Plant density and height
  • Leaf area index
  • Litter fall and decomposition rates in stream flow
  • Use ~10% of surface water runoff
• Threaten endangered plant species and altered bird distributions
  • Other DTIS having major ecosystem impacts
  • Chromolaena, schinus molle, prosopis

Environmental Impacts - DTI impacts in South Africa not only terrestrial

• Aquatic invaders grow rapidly, forming dense mats
  • Examples: Water hyacinth and red water fern
• Negative impacts include
  • Water loss via evotranspiration
  • Oxygen depletion
  • Reducing potable water quality and quantity
  • Impeding navigation, blocking flood control structures and collapsing bridges
  • Clogging irrigation and hydropower pumps
  • Limiting access for recreation and fisheries
  • Decreasing property values
  • Mosquito breeding

Environmental Impacts

• Positive impacts - Water hyacinth
  • Feed for livestock
  • Mulch for crop production
  • Fiber for paper and weaving baskets
  • Biological filtration/nutrient removal
• Drawbacks
  • Plant contains 96% water
  • Harvesting expensive
  • Promoting utilization leads to further spread

Economic Impacts - Cause of alien plant invasions

• Unintended consequence of economic activity
  • Globalization of world economy
  • Liberal trade laws and regulations
• Human behavior primary driver of plant invasions
• Facilitates establishment and spread
  • Modern transportation, promoting trade of goods
  • Large-scale conversion of natural vegetation (disturbance)
• Plant invasion tied to economics and ecology
• Credible economic assessments involve both market and non-market impacts
• Results must enable decision-makers to make the right decisions

Economic Impacts - Key elements for invasive plant control

• Institutional regulation of human behavior
• Appropriate policies and strategies
• Complications and challenges
  • Difficulty quantifying invasions in economic terms
  • Tendency to avoid problem until crisis occurs
  • Conflict of interest species - beneficial and deleterious impacts
  • Variability of net economic impact estimates - Scale, scope, timing, and approach
  • Public good issue - Control measures under applied

Approaches to Economic Evaluation

• Invasive plants have both positive and negative impacts
• Need to identify who’s affected and whether effects are positive or negative
• In the 1990s, invasive woody plant impacts - Quantified in terms of effects on water resources
  • Persuaded government to take the problem seriously
  • Water in South Africa limiting factor
• Most studies report positive return on investment, especially role of biocontrol research
• Acacia industry - US$1.4 billion in water loss vs. less value of wood chips, etc
• Studies show invasive plant control makes economic sense
• Most benefits derived from curtailing spread, reducing densities, and mitigating future impacts
• Challenge for “conflicting interest” species
  • Mesquite, positive and negative impacts - Loss of groundwater vs. livestock fodder, shade, shelter, and biofuel

Approaches to Economic Evaluation - Framework for Mathematical Model

• PVC = DBC - DCC + PEoBC - NEoBC
• PVC = Present Value of Integrated Control
• DBC = Present Value of Direct Benefits of Control
• DCC = Direct Costs of Invasive Plant Control
• PEoBC = Present Value of + Control Externalities
• NEoBC = Present Value of - Control Externalities

National Scale Assessment

• Alien plants degrade rangelands
  • Replace palatable with unpalatable species
  • Restrict access by livestock and ranchers
• Livestock carrying capacity decreased by 123 K LSU
• Invasive plant cost summaries
  • Water-related losses - US$773 million
  • Livestock grazing losses - US$45 million
  • Biodiversity losses - US$57 million
  • Total - US$867 million

Dealing with the Problem - Working for Water program

• Invasive plant control and social development
  • Employs poorest people in communities nearest to alien plant infestations
  • Increased income and nutrition
  • Provided better clothing
  • Increased educational opportunities
  • Provided small business training
  • Procurement of protective clothing, tools, and equipment
  • Raised public awareness
• Social development program
  • Child-care program for working women
  • HIV/AIDS awareness campaign
  • Prisoner release rehabilitation

Perscription for Success

• Actively manage invasive plant spread
• Use non-invasive species when possible, introduce biocontrol agents early on
  • Use biocontrol to limit seed production of otherwise invasive species
• Recognize potential invaders early and implement precautionary measures
• Educate public about dangers and invasive species costs
• Encourage use of non-invaders for ornamentals
  • “Alter-natives”

Case Study

• Economic Benefits of Red Water Fern Biocontrol
• Complete control in 2 years

Economic Advantages of Biocontrol

• Labor intensive clearing of invaders in the working for water program not sustainable
• Needed to develop program components to prevent reinvasion
• Biocontrol - One of the most cost-effective tactics for reducing invader impacts
  • Of 46 weed species, 22 under complete or sustantial biocontrol
  • Total cost for biocontrol from 1997-2000 - Only $3 million
  • Returns on investment unprecedented - 50:1 - lantana, caesalpinia, chromolaena - 3726:1 - Australian acacias
  • Including biocontrol as component of working for water program expected to reduce costs from $60 to $20 million per year - 67% cost reduction

Conclusions

• Alien plant invasions severe in South Africa and intervention programs justified
  • Reduced biodiversity
  • Changes in water flow
  • Genetic hybridization
  • Changes in fire regimes
  • Loss of grazing lands
  • Increase disease vectors
• Impacts pervasive and have important implications for humans and environment
• Unique aspect is ability to leverage further
  • Benefits from control programs
  • Funds for working for water program sourced from poverty relief budget
• Convincing economic assessments needed to maintain support
• Biocontrol offers considerable benefits, which significantly outweigh costs
  • Most cost-effective intervention
  • Subject of debate because introducing more alien species with some degree of risk

Alien Invertebrate Animals in South Africa

Introduction

• Compared to plants and animals, alien invertebrates are not well studied in South Africa
• ~56 insects introduced for biocontrol of weeds, >50% have documented impact
  • Impacts on non-targets not well studied
• Invasive invertebrates causing large-scale negative environmental and health impacts
  • Yet to invade South Africa, escaping notice, or not investigated
• Introduced crop pests receive considerable attention, $1 billion in losses
  • Red scale, Mediterranean fly, and codling moth

Mediterranean Fly

• Ceratitis capitata - One of the most economically costly pest species
• Spread from native Afrotropical range to main fruit-producing regions
• First confirmed presence in South Africa - Late 1800s
• Successful establishment
  • Polyphagous life-history
  • Short development time
  • High population reproductive potential
  • Broad climate niche
• Larvae and probing by adult females cause most damage
  • Fruit vulnerable to secondary infections by pathogens and pests
• Can lead to 100% crop losses

Argentine Ant

• Native to Argentina and Brazil
• Arrived ~1898 in cattle fodder
• Globally, invaded Bermuda, Mediterranean Europe, Southwest U.S., Chile, Western Australia, New Zealand, and Hawaiian Islands
• Established in Cape Peninsula
• Generally found in lower altitude sites and areas with established roads
• Not found in sites accessible only on foot

Argentine Ant - Environmental Impacts

• Displace native ants by aggressive behavior, chemical defense, abundance, and interference competition
• A few native species co-exist due to differences in foraging patterns, small body size, and stealth
• Disrupt mutualism by interfering with plants relying on native ants for seed dispersal (myrmecochory)
• Obligate Myrmecophilous lycaenid butterfly caterpillars at risk
• Impact fynbos by affecting pollination
• Impacts on ground inhabiting insects unknown

Argentine Ant - Agricultural and Household Impacts

• Attracted to honeydew produced by Hemiptera
  • Mealybugs, scale insects, and aphids
• Protect pest Hemiptera from natural impacts
• High densities in citrus and guava
• Presence of ants deters pollinators
• Beehives attacked and destroyed
• Outcompete bees for nectar by nocturnal activity
• Invade homes to forage for food and water

Varroa Mite

• Most serious 20th century bee pest
• Spread from Asia, benign on natural host Apis cerana
• A. Mellifera unable to tolerate ectoparasite
  • Capable of killing entire honeybee colony
• Unique life cycle adaptations
  • Fertile female invades uncapped cell and feeds on bee larva
  • First egg is male, remainder female
  • Male mates with sisters and dies
  • Mother and daughters emerge with bee
  • Drone (male) brood preferred over workers
• Spread between colonies by flight

Varroa Mite - Environmental and Agricultural Impacts

• Brood death and developmental abnormalities
• Virus also implicated in colony death
• Wild bee populations in Europe and US - Mite mortality
• May be less virulent to African honeybees
  • Shorter post-cell capping developmental period - Limits mite reproduction
  • African bees exhibit defensive behavior
  • Less damaging under tropical conditions in South Africa
• Greatest impact on wild bee populations
  • Implications for biodiversity
  • Loss of plant species - Affects herbivores
  • No natural enemies for mite

Varroa Mite - Economic Impacts

• So far, extremely damaging to colonies
  • Loss of pollination to commercial crops and associated job losses
• Beekeeping will become difficult and expensive
• Reduction in colonies and wild bees available to commercial beekeepers
• Major impact on small-scale rural beekeeping

Spotted Stem Borer

• Chilo pertellus
• Native to Asia and India subcontinent
• First discovered in South Africa in 1958 after invading African continent in 1932
• Dominant in humid, coaster regions
• Recently, higher-altitude grain growing areas
• Displacing Busseola fusca

Spotted Stem Borer - Agricultural Impacts from Native and Introduced Stalk Borers

• Major pest of cereal crops
  • Maize and grain sorghum
• Bivoltine (2+ generations) during summer periods
• Cereal crop losses between 10-100%

Spotted Stem Borer - Economic Impacts

• 44th out of 101 most important crop pests
• 7th most important lepidopteran pest
• High yield losses and control costs
  • Insecticide costs - $2.5 to $7 million
  • Effective only against first instar (exposed)
• High cost and limited effectiveness of pesticides led to the adoption of alternative methods
  • Culturla control - Tillage control, interplanting with Napier grass (trap crop) - Reduction in maize (89%) and sorghum (94%)
  • Biological control with parasitoids - None established, ineffective

Red Scale

• Native to Central Asia and India
• Major pest of citrus
• Introduced > 100 years ago
• Life cycle
  • Female lives under a circular, reddish-brown covering
  • First instars (crawlers) leave covering and infest fruits, leaves, twigs, and branches
  • Become sessile
  • Up to 3 generations annually

Red Scale - Agricultural Impacts

• Globally, most important pest in terms of control costs and research
• Attack various fruits and ornamentals heavy infestations on citrus and roses
• Losses based on severity
  • Light infestation - Rejection of fruit for export
  • Moderate - Fruit rejection, leaf and fruit drop
  • Heavy - Unsalable fruit, defoliation and death
• Infestations tied to history of insecticide use
  • Sprayed with organophosphates (OPS) in 1948
  • Developed resistance to OPS in 1974
  • OPS replaced with oils, natural enemy resurgence
  • Current IPM systems effective

Red Scale - Economic Impacts

• Damage peaked with OPS resistance and absence of natural enemies
• Demand for blemish-free fruit high, small-scale infestations not tolerated
• During 1966 - 1967, red scale caused 50% of the 25% of fruit crops not acceptable for export
• During same time, cost of chemical control on citrus grove - $1 million
• Switch to IPM
  • 6X reduction in spray costs
  • Doubled the amount of exported fruit OPS replaced with oils, natural enemy resurgence

Snail Pests

• Two invasive species from North America introduced via aquarium trade
• Widespread occurrence in rivers and catchments, especially near urban centers
• Life history attributes conducive to invaders
  • Tolerate wide range of temperatures of aquatic habitats - Mud and vegetation, rivers, streams, lakes, and containers
  • One species capable of self-fertilization
  • Colonization of disturbed habitats
  • High dispersal and reproductive rates
  • Short generation times
  • Low susceptibility to predators

Snail Pests - Environmental and Economic Impacts

• Info on ecological impacts lacking
  • Predation on at least one native snail
• Threaten health of livestock and wild ungulates
  • Intermediate hosts for two liver fluke species
  • Ability to survive out of water may increase transmission to fluke to definitive host (cattle) - Parasite encysts on forage grass
• Economic impact to small farmers high
• One species intermediate host of rat lung nematode - Causes human meningitis

Mediterranean Mussel

• Most widespread, successful marine alien
• Probably introduced in 1970s by humans
• Early 1990s, spread as far East as Port Alfred
• Dominant intertidal organism along the entire West Coast
• Biomass ~194 tons/km

Mediterranean Mussel - Ecological Impacts

• Rapid growth, high reproduction, and tolerance to desiccation
• Three major impacts
  • Compete for substrate space - Displace native species
  • Provision habitat for other species - Support denser invertebrate fauna
  • Increase food for predators - Oystercatcher birds switched diet away from limpets

Mediterranean Mussel - Economic Impacts

• Fouling of ships’ hulls and intakes
  • Mechanical removal - Mussel beds established on mudflats
• Mariculture industry within Salanha Bay
  • 2,145 tons
  • $3.5 million
• Benefit likely outweighs cost

Summary

• Range of realized and potential impacts
• Human activities - Dispersal and spread of invertebrates
• New invaders - Affect environmental and economic interests
• Argentine ant and varroa mite - Global threat to world’s rarest plant biome
• Mussel introduction - Positive economic impact

Module 12

Invasive Vertebrates of South Africa

Introduction

• Ecotourism South Africa’s newest economic growth factor
• Important to preserve protected areas and landscapes
• Benefits of maintaining biodiversity
  • Ecological services
  • Harvesting game
  • Aesthetic and cultural values
• Challenge - Establishing balance between economic development and conservation policies
• Introducing potentially invasive vertebrates alters valuable environments
  • E.g., human introduction of ungulates for food and sport
• Introduction of 21 invasive fish species
  • Profound on aquatic ecosystems
  • Extinction of native fish, amphibians, and invertebrates, but alien fish - Drivers of economically important fisheries industry
• Implementation of laws restricting importation and movement must balance trade-offs between economic gain and biodiversity loss
• Understanding kep factors of invasion biology crucial - e.g., dispersal ecology
• No consistent pattern for introductions
  • Despite freshwater hot-spot, no marine fish
  • Number of alien bird, reptile, and amphibian species intermediate to low, perhaps merely undetected
  • “Absence of evidence not evidence of absence”
• Number of introduced mammals high but number of invasive species low
• Alien bird establishment on islands not > mainland
  • Runs counter to island biogeography theory
• Evidence-based evaluation of each major taxon regarding environmental, agricultural, and economic impacts
• Consideration for new research directions
• General examination of legislation governing alien species importation and movement
• Extralimital: Invasion by indigenous species outside native range but within given geopolitical boundary

Freshwater Fishes

Freshwater Fishes

• South Africa hot spot for alien fish invasions
• Started in early 18th century with goldfish for ornamental purposes
• Currently, 24 alien and 19 native species introduced in South Africa’s water bodies
  • 21 species documented as invasive (~ 49%)
• Humans responsible for introduction and spread
  • Propagation occurred at state-funded hatchery in Cape region
  • Distributed to other provincial hatcheries via formal stocking programs
• Reasons for Introductions
  • Angling or fishing
  • Biocontrol programs
  • Pet trade
  • Unintentional extralimital movement via inter-basin water transfers
• Angling
  • Introductions during late 19th and early 20th centuries focused on recreational angling
  • Rainbow and brown trout
    • Successful establishment in cool, clear oxygen-rich waters in high-altitude or temperature areas
  • Common carp and trench-coarse fish
    • Stocked in warmer, lowland rivers

Angling

• Demand for predatory species caught with lures
• Large-mouth bass
  • Warm slow lentic/lotic water
• Small-mouth bass
  • Cooler lentic/lotic water
• Spotted bass
  • Turbid and flood waters
• Bluegill sunfish
  • Predator and food for bass
• Banded and Mozambique tilapia
  • Extralimital food for bass

Biological Control

• Several species distributed from fish hatcheries for mosquito control in 1930s - 1940s
  • Mosquitofish, guppy, and goldfish
• Feral guppy and goldfish populations - limited to urban streams and reservoirs
• Mosquitofish widely distributed
  • ~ 50 of South Africa’s river systems
• Asian grass carp - introduced into farm dams for aquatic weed control
  • Diploid carp widely established in river systems
  • Considered a pest in Vaal River due to high densities

Aquaculture

• Escape from aquaculture operations resulted in 4 species invasions
  • Rainbow trout
  • Common carp
  • Nile tilapia
  • Silver carp
• Silver carp imported from Israel in 1975, thought unable to spawn
  • Viable populations in Olifants-Limpopo River system

Ornamental Fish Trade

• Aquarists likely responsible for unwanted release of 4 species in South African lakes and streams
  • Feral guppy
  • Swordtail
  • Goldfish
  • Armored catfish

Inter-Basin Water Transfers (IBTs)

• Establishment of Orange River (OR)
• Fishes in Sundays and Great Fish Rivers
  • Orange/Great Fish River IBT scheme completed in 1975
  • 82 km tunnel
• Facilitated transfer of smallmouth yellowfish, mudfish, and sharptooth catfish

Extent of Problem

• Alien (17%) and extralimital (71%) fishes common inhabitants of all major river systems
• Continued spreading by IBTs and angler illegal stocking exacerbates problem
  • Sharptooth catfish - large predator - EA urgently needed
  • Nile tilapia - increasing its range

Environmental Impacts to Indigenous Fish Species

• Transfer of parasites
  • Grass carp tapeworm - 2 yellowfish
• Direct predation
  • Bass and trout - Extirpation of threatened and endangered minnows, and major trophic shifts
• Ecosystem effects
  • Common carp increases turbidity
  • Linked to decline of largemouth yellowfish
• Hybridization between
  • Mozambique and Nile tilapia
  • Genetic integrity threatened

Economic Impacts

• 2007 survey - 1.5 million freshwater anglers
• Large recreational fishery depends on alien fishes
  • Carp, trout, and bass
• Fishing expenditures contribute significantly to national economy
  • ~US$1,000/angler/year
  • Total economic impact for 10% - US$11.2 million
    • Bank angling for carp - 40%
    • Fly fishing for trout - 40%
    • Bass angling - 13%
• Food security in rural communities
• Aquaculture - US$5 million
  • Pet trade, tilapia, trout

Dealing with the Problem

• Once established, impossible to eradicate
• Eradication with icthyolites possible
• In large systems, removal impractical/unfeasible
• Future management - Exclusion from sensitive areas and limiting spread
• Areas for use of alien species - Compromises between recreational, economic and conservation interests
• Enforcement of new regulations - education campaigns crucial to increasing awareness and compliance

Reptiles and Amphibians

• Few well-known invasive species, but several examples causing significant impacts in other countries
  • Brown tree snake - Guam
  • Cane toad - Australia
• Biggest threat - Increasing importance of global economies
  • Pet trades - Deliberate
  • Cargo and nursery trades - Accidental
• Diverse reptile fauna in southern South Africa
  • South African Reptile Conservation Association (SARCA) - Reported 500 species
  • High diversity of lizards and turtles
• Gutteral toad
  • Extralimital range expansion - North and East South Africa to West Cape province, 1997
• Painted reed frog
  • Similar jump dispersal and multiple introductions in West Cape province via nursery, fruit, and vegetable trades
  • Spreading in agricultural and natural areas
• African clawed toad
  • Extensive translocations in South Africa via irrigation canals and ditches
  • Range expansion and hybridizations with native clawed toad - Predation and resource competition
• Flowerpot snake
  • Adventive since 1800
  • Arrived with plants from East Indies
  • To date, no reported negative impacts in Cape Town gardens
• Geckos - 2 species
  • Cape day gecko
  • Tropical house gecko
  • Displacement of native geckos
• Impacts or potential impacts
  • No evidence of economic, environmental, or agricultural impacts from alien introductions
  • With increasing trade, important to predict negative impacts in context of impacts identified elsewhere
• Hybridization
  • Genetic introgression - Legitimate concern
    • Loss of unique adaptation and diversity
  • Within pet trade, deliberate production of novel color morphs
    • Native Natal python x alien Burmese python
• Competition
  • Between native and alien species especially South Africa’s diverse reptile fauna
  • Ecological niche displacement - Vulnerable frogs, red-eared slider
• Novel pathogens
  • African clawed toad vector of amphibian Chytridiomycosis
    • Causes mass mortality and population declines
    • Chytrid organism endemic to South Africa, native frogs resistant
  • Introduction of novel strains could devastate South Africa’s native frogs

Novel Pathogens

• Inclusion body disease in boas
  • Potentially catastrophis effects on natal python
• Ticks of reptiles and amphibians
  • Vectors of reptile and other diseases
  • Heartwater disease in livestock
• Ranaviruses
  • Affect fish, amphibians, and reptiles
  • Linkage between aquatic and terrestrial organisms
  • Implicated in amphibian declines
  • African clawed toad - Potential reservoir species
  • Aquaculture and pet trade introductions increase disease risk

Human Health Risks

• Salmonella
  • Spreads from pet slider turtles to humans
• Parasites
  • Ticks from turtles
  • Tapeworms from cane toads
• Venomous and constricting snakes
  • In US, 9 people killed by pet pythons, 1993 - 2009
  • 3 constrictors recently banned by USFWS
• Opportunity costs
  • Lack of species ecology info presents a challenge for detecting invasion impacts
  • Kraus (2009) - Must understand species interactions before introduction, opportunity lost

Dealing with the Problem

• South Africa’s regulatory framework
  • Comprehensive and involved input from pet, aquaculture, and nursery trades
• Costs of controlling invasive species always > prevention
• Focus on drivers and pathways
• Biological control unlikely pathway
  • Global awareness of negative vertebrate impacts

Birds

• Long history of alien bird introductions
• 1652 - Europeans began introducing birds
• To date, 77 alien species recorded in South Africa
• 12 species potentially invasive based on population current densities and distribution
• 7 species permanently established
  • Mallard duck, rose-ringed parakeet, rock dove, Indian house crow, starling, myna, and sparrow
  • Associated with humans
  • No evidence of environmental impacts
  • Landscape changes - Negative impacts to economy, agriculture, and environment

Drivers of Invasion

• Urbanization - Favors cliff nesters
  • Swallows, martins, swifts, starlings and raptors
• Afforestation - Favors woodland species
  • Raptors, doves
• Impoundments - Favor fish eaters
  • Waterbirds, waders, kingfishers
• Climate change - Range shifts
  • Seabirds
• Species of special concern
  • Require monitoring and management
  • Guinea fowl, ibis, Egyptian goose, red-billed quelea
  • Abundance, sociability, and large biomass - Potentially invasive outside native range

Invader Comparisons

• Extralimital species - Self driven
• Alien species - All introduced by humans
  • Exception - Indian house crow
  • 69% (53 of 77) imported for pet trade - Escapees and/or deliberate releases
  • Only mallard, parakeet, and myna established persistent populations

Extent of Problem

• Multiple introductions and high dispersal rates
  • Rock dove and sparrow
• Major range extensions
  • Myna and starling
• Complex factors
  • Mallard and parakeet

Extent of Problem - General Trends

• Urbanization, commercial afforestation, and alien plant spread - Range expansion of northern species southward
• Power poles for nesting increased crow densities - Increased seed dispersal and spread of alien cactus
• Creation of livestock and farm dams - Dispersal of aquatic birds to arid areas
• Irrigated agriculture - Food source for invasive crop pests
• Other contributing factors - Climate change and changes in landscape cover

Impacts

• Native and extralimital birds more detrimental than alien species
  • Starling, myna, quelia, and sparrows - Fruit crops and cereal pests
• Interspecific competition and predation
  • Myna and starling
• Alien plant dispersal
  • Myna, starling, and cape crow - Spread seeds of bugweed
• Pathogen and parasite spread to humans
  • Myna and starling
• Chemical/physical damage to buildings
  • Rock doves and house sparrows
• Aircraft collisions
• Hybridization
  • Alien rock dove x native speckled pigeon
  • Alien mallard x native domestic ducks
  • Mallard known to hybridize with 50 waterfowl

Dealing with the Problem

• Data on monetary cost and ecological impacts limited
  • Environmental costs probably insignificant
• Bird banding to improve knowledge of avian biology and management

Mammals

• Introduced into South Africa for various reasons
  • Wool, food - Sheep and rabbits
  • Fur - Nutria and mink
  • Biocontrol and pets - Feral cats
  • Hunting and ornament - European wild boar and fallow deer
  • Escape from captivity - Himalayan Tahr
  • Private landowner releases
• Human-mediated introductions
  • Stowaways on boats/planes - Brown rat, house mouse, roof rat, and oriental house rat
• Game industry - Alien and extralimital
  • Hunting - Addax, oryx, fallow, and red deer

Extent of Problem

• ~ 50 species introduced, only small number invasive
• Invasive species - Ornamentals, game animals, feral domestic animals, livestock, and escapees from captivity
• Introduced mammals invasive on islands - Fallow deer, feral cats, European rabbits, and house mouse
• Fallow deer and red lechwe - Highly invasive on mainland
• Feral pigs, rats, goats, and donkeys causing problems
• Genus Rattus - Largest mammalian genus of invasive and commensal rodents
• First recorded occurrence of oriental house rat in South Africa
• New molecular data show
• South Africa population originated from Far East
• Important implications for epidemiological, agricultural, and conservation biology research
• Game mammal introductions extensive in South Africa - Second only to US
• Range expansion by extralimital species leading to substantial range changes

Impacts

• Himalayan Tahr - Damages vegetation and soil erosion
• Feral domestic and livestock animals - Compete with or prey on native species
• Feral pigs - Prey on threatened and endangered tortoises and small livestock, rooting, wallowing damages agricultural fields and natural areas
• Fallow deer - Better adapted to C3 grasses/climate change
• Other rat problems
  • Murine typhus, rat-bite fever, salmonella, RHF
  • Diseases may increase due to HIV/AIDS compromised immune systems in South Africa
  • Threaten native flora and fauna, especially on islands
• Effects on agriculture/public health
  • Rats - Carriers of zoonotic diseases, destroy grain crops and human structures, and transmit leptospirosis, plague, toxoplasmosis

House Mouse

• Introduced on Marion island by sealers in 1800s
• House cat released for biocontrol, but eradicated in 1990s
• Mouse populations increasing with ecosystem impacts
  • Biomass of invertebrate decomposers declining
  • Population decline of lesser sheathbill, invertebrate consumer
  • Potential predation on albatross and other seabird chicks
• Positive contributions
  • Albino mice/rats - Models for medical experiments
  • Rats - Studies on tracing

Domestic Cat

• Derived from Egyptian wild cat - 4000 BC
• Human-assisted spread
• Most widespread carnivore
• Impacts
  • Hybridization with African wild cat
  • Rabbit and bird predation on Dassen Island
  • Ecosystem effects of predatory and scavenger habits

Grey Squirrel

• Introduced to South Africa in ~1900
• Restricted to urban areas with large seed-producing exotic trees - Oaks, pines
• Some fruit and nut damage - Overall impact minimal
• Potential threat to garden birds and native squirrels

Extralimital Species

• Potential impacts on biodiversity
  • Herbibory, hybridization, and competition
• Nyala outcompeting bushbuck
  • Altering vegetation and risk of hybridization
  • Giraffes altering tree structure/composition
  • Blue and black wildebeest hybridization
  • Springbok infected bontebok with Lungworm parasite
  • Warthog invading nature reserve - East Cape province
  • Impala outcompeting reedbuck in East Cape province
  • Impact of small mammals unknown

Legislation and Policy

• Best science must be incorporated - Defining and agreeing on main objectives
• Commitment to bridging research and raising sufficient funds
• Constraints for policymakers
  • Staying on top of recent science developments
  • Lack of opportunities for communication between scientists and decision-makers

Legislation and Policy - Gaps in Current Knowledge

• Treating species that pose greatest biodiversity threat
• Establishing current distributions and pathways
• Characterizing cryptic invasive species with molecular data
• Integrating invasive species management plans through IDP process
• Increasing use of niche models for projecting impacts of global change

Environmental and Economic Costs Associated with Alien Invasive Species in the U.S.

Introduction

• ~50,000 non-native species introduced into US
• Corn, wheat, rice, cattle, poultry - Beneficial
  • Account for 98% food production, valued at $800 billion
  • Other exotic species introduced for landscaping, biological control, sports, pets, etc.
• Some non-indigenous species - Major economic and environmental losses
  • ~$100 - $200 billion damages report from exotic species
  • ~40% of threatened and endangered species at risk from competition/predation
  • Worldwide, ~80% impacted by invasive species

Environmental Damages and Control Costs

• Estimating economic impacts of non-native species on agriculture, forestry and public health difficult but quantitative data available
• Most plant and vertebrate introductions intentional whereas most invertebrates and microbes accidential
• Since the 1960s, biotic invasions increasing
  • Population growth
  • Rapid transportation
  • Environmental degradation

Plants

• Introduced for food, fiber or ornaments
  • ~5,000 introduced species escaped vs. 17,000 native species
• Non-native weeds invading ~700,000 ha of natural areas
  • Florida, 900 of 25,000 (~4%)
  • Hawaii, 950 of 2,700 (~35%)

Key Examples - Terrestrial Weeds

• Purple loosestrife - National parks, successful biocontrol
• Yellow star thistle - California, grassland invader
• European cheat grass - Idaho, Utah, alters fire regimes
• Salt cedar
• Brazillian peppertree
• Melaleuca

Key Examples - Aquatic Weeds

• In Florida, alien species altering biodiversity, navigation, nutrient cycles, recreation
  • Hydrilla
  • Water hyacinth
  • Water lettuce
  • Hygrophila
• ~$100 million spent controlling aquatic weeds
• ~$20 million in Florida for hydrilla

Mammals

• ~30 domestic species introduced into US - Dogs, cats, horses, burros, cattle, sheep, pigs, goats, and deer
• Prey on native animals and plants, impact threatened and endangered species and contribute to soil erosion
• Small mammals also cause problems - European and Asiatic rats, house mouse, and European rabbit
  • Pests on farms, industries, and homes
• Rats
  • Cause fires and transmit diseases (Salmonella, plague)
  • Prey on native vertebrates and invertebrates

Mammals - Indian Mongoose

• Introduced into the Caribbean and Hawaii in the late 19th century for control of rats in sugarcane
• One of the first biocontrol failures
• Controlled Asiatic rat but not European rat
• Preyed on native ground-nesting birds, amphibians, and reptiles
• Led to the extinction of several herps in Puerto Rico
• Major vector of rabies and leptospirosis
• Total cost ~$50 million in Puerto Rico and Hawaii

Mammals - Pet and Feral Cats

• Threat to native birds, mammals, amphibians and reptiles
• ~9 birds killed/cat annually
• Total loss - 480 million birds and ~$18 billion

Mammals - Wild Dog Packs

• ~1 billion pet and feral
• Kill deer, rabbits, cattle, sheep and goats
• Major livestock problem in Florida and Texas
• Total livestock losses nationwide ~$10 million
• ~5 million humans attacked by wild and pet dogs
• Cost for treatment + LEO = $250 million
• Dogs kill 15 to 20 children annually

Birds

• ~10% of US birds exotic
• ~56% pests
• Pigeon is prime example in US
• Myna bird in Hawaii - Major disperser of invasive weed lantana

Birds - English House Sparrow

• Introduced in 1853 to control cankerworm
• By 1900, became pest of homes, buildings, and agriculture
• Harass native birds (e.g. robins and orioles) and displace bluebirds, wrens, and purple martins
• Vector of 29 human and livestock diseases

Birds - Common Pigeon

• Most important bird pest in US
• Cause ~$2.2 billion in damages annually
• Feeds on grain
• Reservoirs and vectors of human and livestock diseases, e.g. Encephalitis
• Fouls buildings, cars, and statues by nesting habits

Reptiles and Amphibians

• 53+ species introduced
• Found in subtropical states and US territories - Florida, Hawaii, and Guam

Amphibians and Reptiles - Brown Tree Snake

• Introduced into Guam after WWII in military goods
• Densities increased to 100 per ha
• Devastated native birds, mammals, and lizards
• Attack chickens and eggs, impacting farmers
• Causes public health problems
• Children susceptible to snake’s venom
• Climbs power poles causing power outages - ~90 outages per year, costing ~$1 billion
• Total control and research costs ~$16 billion

Fish

• ~150 species introduced into US
• Greatest impacts in states with mild climates
  • Florida - 50+ species
  • California - 56 species
  • Hawaii - 33 species
• ~70 native species threatened by invaders
  • Grass carp and common carp
  • Alter ecology of aquatic ecosystems by reducing vegetation and increasing turbidity
  • Causes extinctions of some native fish
• Some economic benefit via sport - Fishing, $70 billion annually

Arthropods and Invertebrates

• ~4,500 arthropods introduced into US
• 11 earthworms, 100 aquatic invertebrates
• ~95% adventive via plants and ballast water
• Hawaii accounts for > 50% or ~2,600
• Examples
  • Wooly adelgid - Past 20 years destroyed 95% Fraser firs, loss of 2 native birds
  • Red imported fire ant - Kill chickens, snakes, bobwhite quail, Texas - $300 million in damages
  • European green crab - Impacts native oysters and softshell crabs, economic impact - $44 million

Mollusks

• ~88 adventive species in US
• Zebra mussel
  • First discovered in Detroit’s Lake St. Clair
  • Arrived from Europe in ship ballast water
  • Widely established in Eastern US
• Quagga mussel
  • Displacing zebra mussels - $2 billion in damages
  • Clog water intake pipes, filtration and power plant
• Asian clam
  • Grows and spreads less rapidly but causes similar damage - $1 billion per year
• Shipworm - Introduced in San Francisco Bay
  • Damages estimated at ~$400 million

Weeds

• ~500 introduced plants are weeds
• Several introduced as crops, trees, crop seeds, and ship ballast
  • Johnson grass, kudzu, cogon grass, melaleuca, yellow rocket (Barbarea vulgaris), and Canada thistle
• Reduce crop yields by ~12% or $33 billion
  • 50% - 73% of weeds non-indigenous
  • ~$4 billion spent on herbicides
• Lawn, garden, and golf course weeds
  • Control costs ~$36 billion

Vertebrate Pests

• Horses, burros in Western US - Graze on native vegetation, annuals replace native perennials
  • Reduce available food for bighorn sheep, birds
  • ~$5 million in forage losses
• Feral pigs - Alternative vegetation, contribute to invasions by annuals and soil erosion, damage field crops, and disease reservoirs
  • Serious problem in California, Hawaii, Florida, and Texas
  • In US, damages estimated at $1 billion
• European starlings - Threaten crop production, displace native birds, and transmit diseases
  • Total crop losses ~$800 million

Insect and Mite Pests

• ~500 non-native arthropod crop pests in US
• Insects destroy ~13% crop production and ~9% forest products
• Introduced pests cause ~$21 billion in total losses
  • Gypsy moth intentionally introduced for silk production in the Northeast - ~$11 million for control
  • Emerald ash borer ~$1 billion - No known control

Plant Pathogens

• ~20,000 microbes invaded US
• Losses ~$16 billion crop, ~$9 billion forests
  • 65% due to non-native diseases - Chestnut blight, Dutch elm disease, citrus greening, laurel wilt

Livestock Pests - Arthropods, Microbes, and Parasites

• Losses ~$9 billion
• Key example
  • Face fly

Human Diseases

• Increasing threat from exotic diseases
  • Rapid transportation, encroachment of civilization into new ecosystems, and increasing environmental degradation
• Major non-native diseases with greatest impacts
• Syphilis
  • Outbreaks still occur due to resistance to antibiotics
  • Exacerbated by HIV infection
• Influenza
  • ~550 deaths
  • Hospitalizations $300 million
• HIV/AIDS
  • ~105,000 cases and ~37,000 deaths
  • Health care costs ~$11 billion

Summary

• >50,000 non-native species in US
• Factors contributing invasion success
  • Lack of natural enemies
  • Development of new associations
  • Effective predators in new ecosystems
  • Artificial or disturbed habitats
  • Illegal immigration
• Total economic damages - ~$219 billion
  • Costs of extinctions, losses of biodiversity and ecosystem services impossible to estimate
• Greatest challenge
  • Prevent further damage to US ecosystems

Module 13

Rodents and Other Vertebrate Invaders in the United States

Introduction

• Most invasive vertebrates arrived in the U.S. via human activity or range expansion
  • Direct introductions
  • Accidental transport
• Not immediately recognized as harmful
  • Often championed as beneficial or having redeeming value
• Results in conflicting interests
  • Eradication vs. damage management
• Issues raised concerning
  • Economic damage, ecosystem degradation, competition with rare or desirable native species or perceived threat
• Organization structure for dealing with problem still evolving
  • National invasive species council (NISC)
  • Created by Clinton EO, 1999
  • Co-chaired by the Secretary of Agriculture, Commerce, and Interior
  • Involvement by 13 federal agencies/depts.
  • Developed National Invasive Species Management Plan
• Individual states also developed their own plans
• Invasive vertebrate breakdown
  • Mammals - 81
  • Birds - 99 (total 792)
  • Reptiles - 69
  • Amphibians - 11
  • Fish - 533

Rodents and Other Vertebrate Impacts

• U.S. vertebrate invaders leading cause of environmental change and global biodiversity loss
  • Clear link between ecological and economic systems
• Primary negative economic effects
  • Disease transmission and predation causes mortality in humans, livestock, wildlife
  • Environmental destruction leads to habitat losses, restoration costs
• Secondary negative economic effects cause ecosystem damages, causing ecotourism losses

Rodents and Other Vertebrate Impacts - Challenges for Policymakers

• Developing sustainable methods for invasive species prevention, control, and damage mitigation
• Benefit-cost analysis essential for determining most economically efficient techniques
• Development of Impact Measurement Techiniques
• Damage - avoided method
  • Uses value of resources protected as measure of benefits provided
  • Measured as cost savings from diminished disease, predation, environmental destruction
  • Costs derived from labor and materials used to mitigate damage
  • Total economic benefits = Primary + Secondary effects “saved”

Species Accounts

Norway Rat

• Introduced to North America via Transatlantic shipping - 1775
• Established throughout country, Alaska, Hawaii
• Causes damage to crops and stored products
• Closely tied to human settlements
• Dramatic reproductive potential
  • Gestation period - 3 weeks
  • Sexual maturity - 3 weeks after
• Associated with poor sanitation, trash in inner cities
• Impacts
  • Farms - Damage stored food and grains, egg and chick predation
  • Structures - Damage roads, buildings, bridges, railroads
  • Reservoir hosts of human and domestic animal diseases like salmonellosis, leptospirosis, and trichinosis
  • Rat bites to babies and children
• Management
  • Environmental control and sanitation

Roof Rat

• Also known as black or ship rats
• Establish in Virginia 1600s
• Inhabit port and shore areas Southeast and West North America, Hawaiian islands
  • Recently discovered inland - Phoenix, AZ
• Poor competitors with larger, aggressive Norway rats
• Commensal with man and invades landscapes (forests)
• Impacts
  • Damages orchard, grain and sugarcane crops
  • Preys on ground-nesting birds, nestlings, eggs
  • Caused bird extinctions on islands of Hawaii
  • Reservoir of bubonic plague - Outbraks in California in the 1900s
• Management
  • Same as Norway rat
  • Targeted eradication programs on islands to protect seabird populations

Polynesian Rat

• Native to Southeast Asia
• Not present on U.S. mainland, only Hawaii islands
• Smallest member of genus Rattus
• Primarily nocturnal, like most rats
• Breed year-round, lifespan ~1 year
• Adapted to wide range of habitats - Omnivores
  • Forests, grasslands, sugarcane, seed crops, fruits
• Preyed on by cats, mongooses, other rodents
• Food for Polynesians
• Predators of seabirds, lizards, insects, plants
• Management
  • Rodenticides, trapping, biocontrol by mongoose (failed)

Nutria

• Semiaquatic rodents native to South America
• Invasive in Southeastern U.S.
• Introduced in 1899 for fur production
• Dispersal via fur harm escapees, hurricanes, floods
• Pests of crops, aquatic vegetation, rice, sugarcane
• Alter aquatic ecosystems and marshlands
  • Loss of marshes impacts waterfowl, wading birds, muskrats
• Burrowing weakens irrigation structures, levees
• Host for several diseases
• Management
  • Hunting, trapping - Bounty of $4-5 / tail

Gambian Giant Pouched Rat

• Native to Central and South Africa
• Popular pet escaped on Florida Keys
• Concern for impact to fruit industry on Florida peninsula
• Reservoirs of monkeypox and other diseases
• Large rodent, ~1 meter (3 ft)
• Management
  • Live-trapping
  • Rodenticides

Feral Swine

• Established populations in 33 states, estimated 4 million
• Origin - Escaped domestic swine or releases
• Exceptional high reproductive rate
  • Breed at 6 months, large litter size, year-round
• Impacts
  • Damage property, agriculture, and natural resources via rooting, wallowing, and digging activities
  • Rooting damages equipment, injures livestock, soil erosion
  • Destruction of fencing, predation on wildlife
  • Transmit diseases - Brucellosis, rabies, flu
• Management
  • Fencing, trapping, shooting
  • Developing contraceptive vaccines

Small Indian Mongoose

• Native to Pakistan, India, China, and Indonesia
• Introduced for biocontrol of rats and snakes in sugarcane fields, Puerto Rico, Virgin Islands, and Hawaii
  • Predation not high enough to affect control
  • Opportunistic omnivores
• Few predators or competitors to impact populations
• Inhabit a variety of habitats, breed year-round
• Impacts
  • Damage to agriculture and natural resources
    • Poultry, egg, and game bird populations
    • Linked to extirpation of ground-nesting birds
  • Reservoir hosts of rabies, leptospirosis
• Management
  • Traps, poison baits, or combination

Rock Pigeon

• Known as feral pigeon, rock dove
• Native from Britain to India and North Africa
• Oldest non-native bird species in U.S. - 1600s
• Found throughout U.S., including Hawaii
• Impacts
  • Damage costs ~$1 billion annually
  • Soil buildings, consume and spoil grain
  • Harbor/transmit >40 zoonotic diseases
  • Food for urban-nesting peregrine falcons
  • Popular in parks
• Management
  • Repellants, toxicants, sound/visual devices, trapping, contraception and shooting

House or English Sparrow

• 16 birds released in New York City in 1850s
• Considered “most deplorable event in American ornithology”
• Primarily seed feeders
• Extensive native range - Europe and Asia
• Commensal with humans
• Impacts
  • Consume livestock/poultry grain
  • Create unsanitary conditions
  • Transmit 25+ diseases affecting humans/livestock
  • Harbor numerous ectoparasites, e.g., bed bugs
• Management
  • Combination of trapping, exclusion and nest destruction leading to populations in decline

European Starling

• Listed as one of the top 100 invaders worldwide
• 100 released in New York City Central Park - Early 1890s
• Today, found throughout North America - ~200 million
• Nest in natural and artificial cavities
• Form large breeding flocks
• Impacts
  • Annually causes ~$800 million of agricultural damage
  • Consume fruits and grains, contaminating feedlots
  • Transmit ~25 diseases - Toxoplasmosis, salmonella
  • Deface buildings, inhabit electrical substations
  • Pose a major risk to aircrafts, >2000 collisions since 1990
  • Population in decline

Monk Parakeet

• Native to South America in croplands, savannahs, and woodlots
• Imported into U.S. via pet trade in 1960s
• Largest populations found in Southwest Florida, primarily in urban/suburban areas, steady decline 2005
• Impacts
  • Considered a major crop pest South America, not U.S.
  • Construct nests in substations, towers, and poles
• Management
  • Nest removal but costly $1.5 - $5 million
  • Contraceptives

Brown Tree Snake

• Native to Australia, New Guinea, and Solomon Islands
• Introduced to Huam as stowaways after WWII
• Attained high population densities 50-100 / ha
• Slightly venomous, nocturnal, and arboreal
• Impacts
  • Extirpated native bird and lizard populations
  • Children susceptible to snake bites
  • Loss of pets, poultry, and tourism
• Management
  • Prevent cargo and aircraft entry - Detector dogs
  • Live trapping, hand capture, toxicants, repellants, fumigants, contraceptives

Burmese Python

• Introduced to Florida via illegal pet releases
• Native from Thailand to Vietnam
• Generalist feeders, primarily on birds and mammals
• Unlikely to establish outside Florida
• Impacts
  • Predation on native vertebrates and endangered species, causing severe ecosystem impacts
• Management
  • Strategies for controlling pythons still developing
  • Include capture mechanisms, detection methods, reproductive baits, toxicants

Coqui Frog

• Terrestrial tree frog introduced to Hawaii from Puerto Rico in 1980s
• Widespread on Big Island and Maui - 50K/ha
• Small populations in Florida, California, Guam, and Virgin Islands
• Distinctive call - “ko-kee” produced by males
• No tadpole stage, froglets hatch from eggs
• Impacts
  • Sheer numbers reduce invertebrates, compete with birds, alter food webs and nutrient cycling
  • Reduce real estate values
  • Increased floriculture costs
  • Carrier of chytrid fungus - Linked to frog declines worldwide

Sea Lamprey

• Primitive boneless fish
• Native to the Atlantic Ocean but introduced to Great Lakes
• Possess sucking disk mouth with sharp teeth
• First observed in Lake Ontario - 1830s
• Construction of Welland canal, 1919, facilitated spread in Great Lakes
• Impacts
  • Attach to fish, rasp soft tissues, feed on fluids often with lethal effects
  • Collapse of fishing industry in 1940s-1950s
• Management
  • IPM using lampricides, barriers, sterile males

European and Asian Carp

• European carp: Introduced by U.S. Fish Commission in the 1800s as food fish
  • Damages wetlands and aquatic ecosystems
  • Increases turbidity, competes with native species, predation
  • Targeted as sport fish or for bow hunting
• Asian carp: Escaped aquaculture in 1960s-1970s
  • Resource competition
  • Predation on fish larvae
  • Boating and skiing hazards

Summary

• Worldwide, rodents and other vertebrates impacted humans and quality of life
• Vertebrates - Major cause of invasions
• Disease transmission amplified
• Avoid short-term thinking/planning

Global Threats from Exotic Diseases

HIV/AIDS - Origins

• Human immunodeficiency virus (HIV)
• Causative agent for Acquired Immune Deficiency Syndrome (AIDS)
• Originated from African continent
• Cross-species infections from primates
  • Primates hunted for food
• Main AIDS pandemic subtype (HIV-1) originated from chimps in Central America
• HIV-2 subtype originated from sooty mangabey monkey in West Africa
• Pandemic effects from unprotected sexual contact and unsanitary syringes

HIV/AIDS - Surveillance and Response

• Greatest impact on sub-Saharan Africa
  • About 67% of the 39 million people living with HIV globally (2022) are from sub-Saharan Africa
  • In 2022, around 1.3 million people became HIV-positive and 630,000 people died of AIDS-related illnesses
  • Projected funds needed for AIDS response in low-and middle-income countries in 2025 - $29 billion

HIV/AIDS - South Africa

• One of the countries with the highest rates of infection
• In 2021, 51,000 AIDS deaths
• Businesses impacted due to loss in workforce, productivity, lost skills, and absenteeism
• Initiated 5-year national HIV/AIDS program to address problem
• ~2006, South Africa successful in controlling HIV and AIDS epidemics

HIV/AIDS - India

• Low HIV infection rate (0.2%)
• Poverty, illiteracy, migrant labor, and socio-economic conditions contribute to spread
• Ministry of Health created national AIDS control organization (NACO) to implement AIDS prevention, education, surveillance and research programs

HIV/AIDS - USA

• HIV infection rate low (0.4%)
• HIV diagnoses decreased 12% from 2017 to 2021
• In 2019, U.S. federal funding to combat HIV totaled $36.8 billion

HIV/AIDS - Brazil

• Highest prevalence of HIV infection in Latin America
• Spread by unprotected sexual contact and drug use
• Intravenous drug use - Linked HIV infections declining from drug prevention programs established by the Ministry of Health
  • “Needle exchange program” highly successful
• Risk of HIV transmission reduced by MOH’s program to practice safer sex via condom use
• Socialized health program distributes free generic antiretroviral therapies to patients

HIV/AIDS - United Kingdom

• Spread mainly through unprotected sexual contact
• High HIV infections in intravenous drug use community declined
  • Department of Health adopted needle exchange program

HIV/AIDS - Australia

• Aboriginal populations experiencing HIV epidemics
• 2011-2016, HIV notification rate among Aboriginal and Torres Strait Islander people
  • Increased from 3.6 to 6.3 per 100,000 and then declined to 2.3 per 100,000 in 2021
  • 1.7 per 100,000 among non-Indeginous people
• Low HIV infections in intravenous drug use community
  • Adopted needle exchange program

HIV/AIDS - New Zealand

• One of the world’s lowest incidence of AIDS cases
• Government aggressive in adopting various response programs
  • Needle exchange
  • National media campaigns
  • HIV testing
  • Blood supply screenings

Tuberculosis - Origins

• Uncertain origin
• Evidence of humans infected since Neolithic period (ca. 10,000 BC)
• Perhaps even prevalent in prehistoric populations
• No definitive early evidence of TB in China and India
• TB endemic in migrating European populations but not epidemic in the Americas until Europeans arrived in 1492

Tuberculosis - Surveillance and Response

• Main cause of death among people with HIV/AIDS
• WHO declaered TB global threat in 1993
• 3 TB bacterial strains, only 1 infects humans
• About 23% of world’s population infected
• Annual incidence of TB highest in Southeast Asia (46%) compared to sub-Saharan Africa (23%) and Western pacific (18%)
• HIV/AIDS epidemic and drug-resistant TB strains responsible for increasing number of TB infections

Tuberculosis - India

• Accounts for 26% of world cases
• Kills more people than malaria and leprosy
• DOTS TB control program second largest
  • $100 million lost annually due to TB

Tuberculosis - South Africa

• One of the highest incidences of TB worldwide
• HIV/AIDS epidemic contributes to high infection rates
• National health priority
• Provide accessible and adequate treatment for poor
• Successful treatment rate of 77%

Tuberculosis - United Kingdom

• Low priority until recently
• Re-emergence of TB cases from 1982-1993
  • Men aged 25-64, frequent travelers to India and Africa
• Focus on effective treatment of known TB cases, screening high-risk individuals, improving surveillance and research

Tuberculosis - Brazil

• Ranks 10th worldwide in TB cases
• TB bacterium introduced during 1980s gold rush
• 35% of the population are carriers
• Indeginous human populations (Yanomami Indians) vulnerable
  • TB at epidemic levels in this group
• DOTS program expects to increase the diagnosis rate to 92% and successful treatment rate to 85%
• Created “bonus program” for public health facilities to treat and cure TB

Tuberculosis - Australia and New Zealand

• Australia
  • Highest incidence in northern territories
  • Major health threat to elderly, immigrants and native tribes
  • Providing assistance in combating TB in neighboring countries
    • Papua New Guinea, Philippines, Indonesia, East Timor
• New Zealand
  • TB incidence increasing due to immigrants
  • Control dependent on early reporting and diagnosis, thorough treatment

Malaria - Origins and Surveillance

• Parasitic disease caused by four plasmodium protozoans
  • P. falciparum, P. malariae, P. ovale, P. vivax
• P. falciparum most important
• Origin - Southeast Asia and Africa
• Molecular evidence points to Africa
• Re-emergence of malaria due to several factors
  • Climate change, wars, drug resistance, poor sanitation, and environmntal destruction
• Anopheles mosquitos, primary vectors
• Affects 40% of world’s population in >90 countries

Malaria - Surveillance and Response

• Accounts for 5x number of cases than AIDS, TB, measles, and leprosy combined
• Africa especially hard hit
  • Responsible for 95% of global malaria cases and 96% of global malaria deaths
  • Pregnant women and children under 5 years vulnerable
• Imported malaria cases increasing from globalization
  • “Airport and weekend” malaria
• Drug-resistant malaria strains increasing
  • Especially Southeast Asia
• Preventable disease
• Organizations - RBM, MIM, WHO, MMV

Malaria - India

• Until recently, P. vivax more prevalent than P. falciparum
• Confined to rural areas until urbanization
• Four large epidemics in the 190s
• 25% of health budget spent on prevention and management
• Rise in incidence
  • Drug-resistant malaria strains
  • Urbanization of mosquitos
  • Emergence of P. falciparum

Malaria - Brazil

• Accounts for ~50% of Latin American malaria cases
• ~99% of cases from the Amazon basin
  • P. vivax, P. falciparum, and P. malariae
  • High incidence attributed to environmental degradation from 1980s gold rush mining
• Infection rates high in mining communities and native tribes
  • High-risk groups in the Amazon basin
• Efforts and funding concentrated on preventative treatment

Malaria - South Africa

• Increasing since 1995 due to migrating populations
  • Neighboring countries and international travelers
• P. falciparum dominant strain
• Cost of malaria ~$300 billion a year
  • Estimated GDP $100 billion higher if eradicated
• One of best programs in South Africa
  • GIS mapping and modeling used to predict outbreak areas

Malaria - Australia, New Zealand and UK

• No endemic malaria in Australia since 1981
• Imported cases predominantly P. vivax (46%) and P. falciparum (25%)
• Proximity to neighboring countries with malaria and suitable climate conducive to re-emergence
• New Zealand and UK cases also acquired from above
• All 3 countries advise travelers to use “caution” before, during, and after travel overseas

Cholera - Origins

• Causative agent - Vibrio cholerae
• Evolved on Indian subcontinent
  • Endemic to Bangladesh and deltas of Gange and Brahmaputria rivers
• Thrives in coastal marine environments
  • Enabled rapid spread worldwide
• 7 pandemics during 19th century
• 6 originated from Bangladesh - V. cholerae strain O1
• 1 from Indonesia still spreading
  • V. cholerae strain O1 biotype El Tor
• New strain from Bay of Bengal - V. cholerae O139
• Still contained in Asia

Cholera - Surveillance and Response

• International trade and travel increase risk for epidemics
  • Unsanitary conditions, poor hygiene, overcrowding, and climate conditions contribute to outbreaks
• Affects poor countries with suitable climate for malaria - Subtropical and tropical
  • Major problem in sub-Saharan Africa
• For countries with cholera outbreaks, emphasis on sanitation and hygiene
• WHO implemented cholera control program
  • Emphasis on clean water, sewage control, and personal hygiene
  • 3 vaccines available, 95% effective after 1st injection

Cholera - South Africa and India

• South Africa
  • Highest number of infections during past 20 years
  • Main contributing factors
    • Lack of clean running water and sanitation
    • Shortages of health care workers, medical facilities, and lack of community awareness
  • European Union providing funds for purchasing and installing toilets
• India
  • Seasonal outbreaks
  • Underreporting of infections and deaths
  • Emergence or drug resistance and V. cholerae O139 Bengal strain adding to problem

Cholera - Latin America, Europe, and Oceania

• Latin America
  • 1991 epidemic in Latin America caused high number of infections and deaths
  • Infections increasing in Brazil
  • Implementing small-scale water treatment programs
  • Chlorine tablets for treating household water
• Europe and Oceania
  • Nearly all cases reported in the UK, Australia, and NZ imported, acquired overseas

Influenza - Origins

• Evolved in Eurasian or North American birds and passed ot humans 10,000 years ago
• 3 types - A, B, C
  • Type A (and its subtypes) and Type B impact humans
  • Type A and subtypes infect birds, pigs, horses, and other mammals
• 1918 Spanish Flu worst pandemic disease in history - 20-40 milion deaths
• Type A (H1N1) caused pandemic

Influenza - Surveillance and Response

• WHO established a network of 110 flu centers in 83 countries
• Emphasis on extensive surveillance and vaccine development
• Vaccination most effective means of prevention
• Type A virus causes the majority of outbreaks and cases
• Individuals at greatest risk - Elderly, pregnant women, individuals with compromised immune systems, and people exposed to high-risk groups

Influenza - UK, Australia, New Zealand

• Australia and NZ infections caused by Type A (H3N2)
• Highest infection rates in infants <1 year old and lowest in elderly

Hepatitis - Origins

• One of the oldest human diseases
• Main viruses affecting humans
  • Types A, B, and C
• Hepatitis B probably originated in African primates, close contact with humans facilitated cross-species transmission
• Hepatits A (HAV)
  • Identified in 1973
  • Spread by contact with feces, semen, saliva, and blood of infected people
  • Medical expenses and financial losses due to HAV high
• Hepatitis B (HBV)
  • People suffering from chronic infections suceptible to cirrhosis and liver cancer
  • In Africa, Asia, and South Pacific, HBV contracted during childhood
  • Spread via perinatal and child-to-child transmission, sexual contact, transfusions, and intravenous drug use (IDU)
• Hepatitis C (HCV)
  • Infects only 3% of world’s population
  • Modes of HCV infection - Unscreened blood products, IDU, promiscuity and non-sterlized instruments
  • No HCV vaccine available yet

Hepatits - South Africa and Australia

• South Africa
  • HAV endemic to South Africa
  • Increase in infections prompted the government to improve sanitation, hygiene, and socioeconomic conditions
• Australia
  • HAV outbreaks high in poor socioeconomic groups
  • Largest outbreak occurred by oyster consumption
  • Government promotes vaccination and hygiene

Hepatitis - India, UK, Brazil

• India
  • Blood transfusions main route of infection
  • Professional blood donors - Major HBV risk
• UK
  • Low prevalence of HBV
  • Transmission, mainly by sexual contact and intravenous drug use
  • Needle exchange program reduced HBV infections
  • Universal vaccination program needed to lower infection rate
• Brazil
  • High incidence in Western Amazon basin
  • Infections higher in immigrants than in natives

Hepatits - South Africa, Australia, New Zealand

• HBV infection rate in South Africa higher in rural areas
• Universal immunization program targets newborns and infants up to 1 year old
• Infections in Australia and New Zealand low
• Most infections found in native tribes, immigrants, intravenous drug users