Conservation Biology Exam 2

greatest threat to biodiversity

Ecosystem degradation and loss

Fueled by human population growth and improving standard of living

Ecosystem degradation and loss

The coldest and driest regions tend to be _____ impacted by human impact.

less

Growth has only _____ slightly in some regions.

slowed

Exponential Human Population growth years

0-2100 A.D.

Carrying capacity of about 30,000 was greatly exceeded after removal of predators.

Deer Population in the Kaibab Plateau 1905 - 1940

in all known cases of unchecked growth by populations the end result is _____

collapse

_____ is the ultimate driver of ecosystem degradation

Human Population Growth

has continued largely unchecked for a long time. Growth is coupled with increasing quality of life for people (this is good!). However, increasing quality of life is associated with greater ecological impact. The result is continuing degradation of the global biosphere.

Human Population Growth

_____ is driven primarily by conversion of habitat for

agricultural production. Land development for home and

road building is also important but secondary to agricultural

conversion

Degradation

Air pollution

• Smog, heavy metals, increased UV radiation (loss of

ozone)

- Reduced reproduction/fitness is most common result

Contamination

Huge variety from mud to hot water to a wide variety

of chemicals

- Runoff is one of the biggest contributors

- Freshwater is often much more heavily impacted than marine water

Water Pollution

____ are a type of Contamination

Pesticides

Non-target effects remain largely unknown.

• Use in developing nations is particularly troublesome

- Lack of any regulating body in terms of acquisition,

manufacture and application.

Pesticides

The "______," which

varies in size but can cover

up to 6,000-7,000 square

miles, begins with excess N

and P from agriculture in the

Mississippi River watershed.

In the Gulf, these nutrients

lead to algal blooms and

depletion of dissolved

oxygen, creating hypoxic

conditions and massive fish

kills.

The Gulf of Mexico Dead Zone

have demonstrated negative effects

• Create gradients of toxicity (salt, hydrocarbons)

• Create thermal gradients

• Provide direct access to natural environments for most

invasive species

Roads

Mortality from road construction

• Mortality from vehicle collisions

• Modification of animal behavior (including barrier

effects)

• Genetic isolation and loss of variation

• Alteration of the physical environment

• Alteration of the chemical environment (e.g., air,

water, and soil pollution)

• Alteration of the auditory environment

• Edge effects

• Spread of invasive species

• Increased use of areas by humans

Ecological effects of Roads

Destruction of ecosystems (e.g. fast moving

watercourses), eliminate migratory routes, silting,

etc.

Dams

Elimination or limitation of migration or territorial

movement

Fencing

Many unknown effects (toxic leaching, etc.)

- Known negative effects are negative due to

animals trying to consume or becoming

entrapped.

Trash

Typically a result of reduced or eliminated

vegetative cover

- Increases silting of water

- Decreases arable land annually

- Leads to desertification

• Cultivation and overgrazing are the primary causes

• Loss of grasses and associated animals leads to drier

soils, loss of soil fertility, erosion, inability of native

species to recolonize.

Soil erosion

Soil erosion, Altered fire regimes, and Excessive water use are all types of _____

Modification

Excessive burning and/or wildfires (due to NOT

burning in some ecosystems) lead to deforestation

- Burning suppression leads to ecosystem change

(pyrogenic ecosystems are susceptible to

overgrowth without fire)

Altered fire regimes

Reduced water tables, increasing desertification,

• Loss of watercourses

Excessive water use

Clearing the land of trees and large shrubbery

for:

- Agriculture

- Homes/development

- Logging

- Mines

- Reservoirs

Deforestation

_____ has been responsible for more habitat loss than any other human activity

Agriculture

• Significant loss of plant biodiversity

• Loss of carbon "sinks"

• Produces carbon

• Erosion and desertification

• Water cycles affected when ____ is

significant

Deforestation

Primarily affecting our smallest in size, yet

most important aquatic biomes: wetlands,

rivers, intertidal zones.

- Silting, stripping vegetation, drying out wetlands

(local extinction of wetland plants and animals),

- Burial is another possibility ("filling wetlands")

Draining and Dredging

Modification or degradation (e.g. roads and dams) result in _____

Habitat fragmentation

As fragment size and isolation increases,

biodiversity decreases

ratio of edge (perimeter) to area changes disproportionately.

Edge effects

Circumference (edge) of a circle =

3.14 X diameter

Perimeter (edge) of other shapes (e.g. polygons =

sum of lengths and widths of all edges

will always have less edge per unit area than other shapes.

Circular shapes

will always have less edge per unit area than several

smaller shapes with the same, sum total area.

Larger, intact shapes

The inevitable process of habitat

fragmentation that results from:

1. Road building in the dissection

step.

2. Followed by habitat conversion

in all of the following steps.

Dissection, Perforation, Fragmentation, Attrition

Dissection

Perforation

Fragmentation

Attrition

Things people eat or sell are the target.

Overexploitation

Overexploitation is non random. T/F

True

______ is the most obvious example of human attention resulting in population declines on a large scale.

Commercial fishing

- Results in a wide variety of trophic cascades

- Alters sex ratios, effective population sizes

Commercial fishing

in the Northwest Atlantic of some important fish stocks,

1950-95. Source: United Nations Food and Agriculture Organization (FAO),

Fishstat-PC (FAO, Rome, 1997). Note the collapse (populations dropping to zero

or near zero) in some of the most intensively fished populations. Decline and

collapse is inevitable when large-scale harvest of natural populations proceeds

without regulation.

Commercial harvests

More intense hunting always results in declines of _____ first.

larger species

• Salvelinus alpinus

• Lives in both fresh and

saltwater

• Salmonidae family

• Iceland largest producer at

200 metric tons a year.

Arctic Charr

is a "Best Choice" because it's farmed in an ecologically

responsible manner.

Farmed Arctic Charr

Most commercial fishing done from aquatic farming

Best case scenario

Dissostichus eleginoides

• Also called Patagonian Toothfish

• Found in deep water (3,850m) off

the coast of S. America and

Antarctica

• Greece and Turkey largest producers

Chilean Sea Bass

20% caught illegally

• Extremely hard to regulate

• Australia has only "sustainable fisheries"

Chilean sea bass

Not listed on IUCN Red List

• 1 fish can fetch $1,000

• Black market trading is unstoppable

• Collapse of entire population and fishing

industry predicted in 2-5 years

Worst case scenario for Chilean sea bass

a species established outside its native range.

Exotic species

an exotic species that is successfully expanding its range in the newly invaded region, usually to the detriment of the native species.

Invasive species

ecosystems and species are increasingly similar around the world due to habitat alteration and species introductions.

Global homogenization

____ move the vast majority of exotic species currently.

Humans

Historically, ____ were rare events, especially for less mobile species (e.g. organisms that are not birds).

Invasions

Cargo and any shipping material that contains soil tends to be the most common vehicle. T/F

True

- Rats, mice, insects

Small inconspicuous species

Fleas, lice, small pox, flu and many other viruses, mosquitos (and all of the diseases they vector), etc.

Disease and pest organisms

Hundreds of marine organisms, some soil organisms

(e.g. ants)

Species in ballast

is a driver of invasions

Exotic agriculture

bananas, sweet potatoes, horses, pigs, wheat, citrus.

New world exotics (Old World origin)

tomatoes, potatoes, corn, turkeys.

Old World exotics (New World origin)

_______ are one of the largest sources of invasive species. It is both the plants and the stow-aways in the soil the plants are in that can become invasive.

Ornamental plants

Sport or game species

- Bass, trout, deer, pheasants are ______ species

Recreation species

Pets (large source of invasives)

- Snakes, lizards, fish, algae (fish tank related), cats,

dogs are ______ species

Recreation

Cane toad, rabbits, lots and lots of insects

Intentional (biocontrol)

Africanized honeybee, sea squirt, gypsy moth

Accidental (escapes)

Creation of canals linking bodies of water

Habitat alteration

extinction events verified with the introduction of snakes, rats, cats.

Predation

huge list - mostly of bird or human origin.

Parasites/pathogens

plants are where most data exist

(kudzu, purple loosestrife, etc.)

Competitors

genetic swamping - mallards

interbreeding with numerous natives

Hybridization

predators create trophic cascades, grasses or trees change soil chemistry or alter burning regimes, etc

Ecosystem effects

________= greatest threat to biodiversity

Invasive predators

_____ species listed as vulnerable, endangered, or critically endangered are threatened

596

________ (the greatest threat and globally the worst invasive species) have caused 60 extinctions and threaten another 430 specie

Cats

threaten 420 species

Rats

Introduction, establishment, expansion

Invasive process

Success rates for _______ are surprisingly low: hundreds of

thousands of confirmed "introductions" at

quarantine points (e.g. airports, seaports, etc.)

with only tens to hundreds of "successes"

recorded every decade.

Invasion process

Insect pest and worldwide invader

• Credited with negatively affecting native ant

populations

• Target of chemical eradication and control and

biocontrol on a massive scale

the fire ant, Solenopsis invicta

World-wide introductions for fire ants came from ______, likely via the transport of ornamental plant nursery stock which was also carrying fire ants in the soil.

US populations

Most abundant in human modified habitats

• Absent from relatively undisturbed natural areas.

Ecology of fire ants S.invicta

Control - unmanipulated (5 plots)

Treatment - all S. invicta colonies killed with hot water (5 plots)

Removal experiment of fire ants

Where did the fire ant removal experiment take place

northern Florida (Tallahassee)

_____ are, by far, most abundant in disturbed sites (60-70%

of pasture levels in flatwoods).

Fire ants

_____ populations were unsustainable in

experimental plots without year-over-year additions.

Fire ant

__________ primarily affect ant communities and competition appears

secondary

Disturbance and habitat

Some invasive ants are "______" rather

than "______" of ecological change

Passengers, drivers

_______ are the gold standard for protection, due to the associated biodiversity.

Ecosystems

Almost all ecosystems currently

protected or targeted for protection exist in a

matrix of altered ecosystems. T/F.

True

Category Ia

Strict nature reserve

Category Ib

Wilderness area

Category II

National park

Category III

Natural monument

Category IV

Habitat species management

Category V

Protected landscape/seascape

Category VI

Managed resource protected area

more species per unit area

Biodiversity hotspots