Conservation Biology Exam 3

What Factors keep populations stable (3)

sufficient population size,

habitat and habitat connectivity,

sufficient genetic diversity

Describe Minimum Viable Population and how it is used (4)

the smallest number of individuals in a species required to have a high probability of survival and persistence in the wild over a specified time

Used to establish recovery goals, as MVPs are determined by factors like genetic health, demographic trends, and environmental challenges

Minimum dynamic area (2)

Established after MVP, the amount of habitat necessary to maintain the MVP

What factors make a population susceptible to extinction (3).

1) Loss of genetic variation and inbreeding

2) Demographic fluctuations due to random variations in birth and death rates

3) Environmental fluctuations due to variation in predation, competition, disease, food supply and irregularly occurring natural disasters

What are the 4 evolutionary forces (4)

- Selection (adaptive evolutionary change)

- Genetic drift

- Mutation

- Gene flow (migration)

Describe what is needed for effective Selection and how selection can be used(2)

-Large population size needed for selection to work effectively (imperiled species have a small population size by definition)

• Selection is a consideration for:

- Captivity

- species can adapt to captive conditions

- Exploited populations

- Agriculture

Describe monoculture in Ag and current work being done (4)

• 1900-2000 crops lost 75% of genetic diversity b/c of habitat loss & focus on a few varieties

• Seed banks kept as source of genetic diversity

• Disease resistance often found in a landrace (one variety in a small area or a wild relative)

• Critical to preserve this genetic variation to ensure crop yields

• Researchers combing the world for landraces of major crops to be stored and hybridized with modern varieties

• In a race because traditional farmers now only occupy 10-15% of land and are abandoning diverse crops for high yield varieties

Describe Genetic Drift (4)

• Chance changes in allele frequencies from one generation to the next caused by random sampling

• Causes a loss of genetic variation

• Drift overpowers selection when population size is small (harmful alleles may be fixed)

- 2 sources, bottleneck effect and the founder effect

What are the two sources of Genetic Drift (2)

bottleneck effect and the founder effect

What is mutation and how does it apply to conservation (3)

• Mutation is the ultimate source of novel genetic variation but often deleterious (only 1-2% of mutations are advantageous)

• In conservation, we care about it in particular when we consider:

- The effect of a population bottleneck and recovery

- Gene flow and spread of advantageous alleles

• If other populations exist, migration can bring novel genetic variation to a population and reverse the effects of inbreeding

Inbreeding definition and signifigance (2)

matings among relatives

Small populations also susceptible to inbreeding

Increased homozygosity because relative share alleles

Inbreeding Depression (3)

• loss of fitness (reproductive success, survivorship) due to inbreeding

• Deleterious traits are expressed when inbreeding occurs (increased homozygosity)

• Inbreeding avoidance: dispersal, behavioral inhibitions, incompatibility loci in plants

• When pops are small, can't avoid relatives

Outbreeding depression (3)

• Matings between different pops or spp may occur when pop sizes are small

• If too dissimilar, outbreeding depression may occur

- Incompatibility of chromosomes, enzyme systems, decoupling of co-adapted gene complexes (e.g., behavior and genes)

• Outbreeding depression is usually of less concern

Generally accepted population numbers needed (3)

• N = 500 to balance the rate of new genetic variation produced by mutation and loss of variation caused by drift

• N = 50 to avoid the costs of inbreeding depression (based on animal breeding)

• Origin of 50/500 rule (not always accurate)

• Need more individuals for longer term persistence (2000-3000)

What is Effective Population size (Ne) and how is it used (3)

• Correct number to use for genetic calculations

• Individuals contributing genes to the next generation

• Typically much lower than census size (Ne about 11% of census size)

• Loss of genetic variation is based on Ne

• Ne affected by: - Sex ratio - Variation in reproductive success - Variation in population size

Sources of Variation in reproductive success (2)

• Progeny per parent varies because of genetic, environmental or accidental factors

• In organisms with high reproductive potential, a large number of progeny may come from a few highly successful individuals

Sources of variations in population size (3)

• May vary naturally e.g., butterflies, annual plants, amphibians

• Bottlenecks, founder effects

• Loss of variation related to smallest population sizes

Stochasticity or random variation

• Causes variation in population size

• Environmental and demographic stochasticity

Demographic stochasticity

• Variation in pop size due to variation in reproduction and mortality is demographic variation

• Random fluctuations upwards are bounded by carrying capacity

• Once pop size is below ~50 individuals, individual variation in birth and death rates causes the population size to fluctuate randomly up and down

• Also can get deviations in sex ratio when pop size drop

What is Allee effect and how does it affect populations (5)

• Interaction among pop size, pop density, pop growth rate, and behavior referred to Allee effect

• When pop size is small, groups of animals may be unable to find food/hunt and defend against predators

• Small populations demographically unstable because social interactions can be disrupted

• Trouble finding mates especially widely dispersed spp like bears

• Trouble with pollination: pollen dispersal, pollinators visiting isolated, scattered plants

What is Environmental stochasticity and and how does it affect populations (2)

• Random variation in the biological and physical environment (usually more important than demographic variation)

• Environmental stochasticity affects all individuals in a population (demographic stochasticity is variation among individuals within a population)

Examples of Environmental Stochasticity

• A small pop of rabbits might be affected by fluctuations in:

- A pop of deer eating the same plants

- A pop of foxes eating the rabbits

- Pops of parasites, disease-causing organisms that affect the rabbits - Rainfall

- Catastrophes: droughts, storms, earthquakes, fires (~15%/generation)

- Numerous examples for large mammal dieoffs

Extinction vortices

• The smaller a pop, the more vulnerable it is to genetic factors and demographic & environmental variation that reduce reproductive success and survivorship

Factors Affecting Abundance and Distribution (8)

-Environment

-Distribution

- Biotic interactions

- Morphology

- Physiology

- Demography

- Behaviour

- Genetics

Sources Of life history Data (3)

• Published lit

• Grey lit (e.g. government, IUCN reports)

• Field work

2 methods of monitoring data (2)

• Census: count the # of individuals in a population - if done repeatedly, can look at population trends

• Survey: Repeatable sampling method to estimate abundance or density in a part of a community - counts used to estimate actual population size

Census Vs Survey

• Census: entire population, more precise

• Survey: a sample of the population, generally faster and cheaper than a census

What are Demographic Surveys, what are the benefits and drawbacks (3)

• Follow known individuals of different ages/sizes to determine growth rate, reproductive success, survival

• Usually mark individuals

• Info used in standard life history formulae to calculate rate of pop change and critical stages of the life cycle

• Can provide info on age structure: a stable pop has a characteristic distribution of age classes

• Provides the most information overall & can provide info on how a site should be managed for population persistence

- Ability to predict future pop sizes limited & often incorrect due to highly variable environmental conditions

- Time consuming, expensive, repeat visits, extensive knowledge of sp required

Cons of Demographic Surveys

- Ability to predict future pop sizes limited & often incorrect due to highly variable environmental conditions

- Time consuming, expensive, repeat visits, extensive knowledge of sp required

eDNA

eDNA is DNA detected in environmental samples such as water or soil that is used to confirm the presence of the species that produced it.

iDNA

DNA from a vertebrate that is collected from an invertebrate that has ingested it. It is a method used to non-invasively monitor wildlife by analyzing the DNA found in the gut contents of invertebrates like mosquitoes, leeches, ticks, and flies

Trends in monitoring programs (4)

• Number of monitoring programs has increased, sometimes required by law

• Long term monitoring can help distinguish between long-term population trends and short-term fluctuations caused by variations in weather and unpredictable natural events

• Can also show a positive effect of management, a negative effect of harvesting or arrival of invasive spp

• Monitoring has a long history in temperate countries, esp the UK

Population Viability Analyses (PVA)

• Extension of demographic analyses: risk assessment using math and stats models to predict probability of extinction, change in size, change in area occupied

• Can identify vulnerable stages, the effects of habitat changes, the effects of management

• Uses deterministic and stochastic models

• Deterministic: model output totally determined by parameter values (e.g., birth/death rates) and initial conditions (e.g., initial pop size)

• Stochastic: possesses inherent randomness - the same set of parameter values and initial conditions produce a set of different outputs

PVA sensitivity analyses

influence of a particular parameter or combination of parameters:

try a range of values for uncertain parameters to determine how they might affect the results; which aspects contribute most to vulnerability? target these for management; if uncertain parameters are important, focus research

PVA Limits (4)

• Generally need a minimum of 10 years of data to have good predictive power

• Results can change depending on assumptions and changes in parameters

• Can't incorporate all possible parameters and poor at incorporating unusual weather and other unanticipated events

• Long term predictions are troublesome because errors propagate

• Common in management planning because can estimate the effect of different approaches

• Need a clear understanding of ecology, threats, and demography

What are Metapopulations and what is their significance (2)

a group of spatially distinct populations that are connected by occasional movements of individuals between them

• Useful in models and may be more accurate re: evaluating species status

• Recognizes that local pops are dynamic, and that migration is important

Long-term monitoring

To understand ecosystems and reasons for pop changes, need to monitor pops and environmental parameters (temp, rain, humidity, etc.)

LTER

Long Term Ecological Research programs to monitor the ecology of a site over time

Because some pops are highly variable, many years of data are required to understand whether a spp is declining or just experiencing low pop size in accordance with its regular pattern of variation

What are the three approaches to establishing new populations (3)

• Reinforcements

• Reintroductions

• Introductions

What is Reinforcement (1)

Augmentation - adding extra individuals (captive bred or wild) to an existing population to increase size or the gene pool

What are reintroductions (1)

Releasing captive bred or wild individuals into an extirpated part of the historic range

What are introductions and when are they used (2)

• Captive bred or wild individuals released to a suitable area outside of the historic range

• When done because of projected climate change, often called assisted colonization

What is headstarting (1)

• Raised in captivity during vulnerable stages and then released e.g., turtles

What is establishing new populations and what are 3 cons (4)

Captive breeding and release into new areas

• Establishing new pops is expensive and time-consuming

• Can be highly emotional, important to include local people so that they have a stake

• Also better to provide incentives rather than impose restrictions and laws

Genetic considerations of establishing new populations (5)

• Loss of variation in captivity

• Adaptation to captivity

• Lower ability to persist in the wild (e.g., Pacific salmon and other spp with high Ne)

• Choose individuals to avoid issues with inbreeding and produce a genetically diverse population

• Similarity/dissimilarity

Translocation Considerations (5)

• Hard releases: may disperse explosively

• Occasional, temporary help (soft release) or force individuals to survive on their own?\

- Greater success in high quality habitat (84%) vs poor quality habitat (38%)

- Greater in core of historical range (78%) than at the periphery (48%)

- Greater with wild caught (75%) vs captive bred individuals (38%)

- Greater for herbivores (77%) than carnivores (48%)

- Increased with the # of individuals released (up to 100)

- Less success for endangered spp than spp managed for hunting

Why do we monitor translocations (4)

• Needs to happen over several years

• What happens to the released individuals?

• What happens to the rest of the ecosystem?

• What are the costs?

Learned Behavior Considerations with relocation (5)

• Social spp often learn behaviour from parents and other members of the population

- Search, capture and consume prey (e.g., teamwork in carnivores; seasonal migration patterns in hornbills)

- Greatest threats to released animals are predators, starvation, habitat quality

- Captive raised animals may require training

- Social interactions difficult to teach

Campbell Island Teal reintroduction

• Subantarctic island • 11,300 hectares

• 3 landbirds extinct, several seabirds extirpated

• 2001 Norwegian rats eradicated

Effects

• Flightless & nocturnal

• Rediscovered on Dent islet in 1975 (world's rarest duck)

• 1984 captured for captive breeding, finally bred in 1994

• 3 X c. 50 teal reintroduced from 04-06

• Nests & chicks found

Restoration of Santa Cruz Island (CA)

• 12 endemic species

• 1980s sheep eradicated

• 2004 feral pig eradication initiated

- Relocation of golden eagles

• None returned

- Captive breeding of foxes

• Wild population c. 300

- Reintroduction of bald eagles

• Now breeding

Factors influencing reintroduction success (3)

- habitat quality

- core of historical range

- number of individuals

Where do New plant populations come from and how are they different from wild populations (2)

• Botanists often germinate seeds and grow plants in protected environments, followed by transplantation

• Often flower and fruit one year earlier than plants grown from seed sown in the wild

• Sometimes transplant wild individuals if a population is threatened

Key factors for re introduction success in plants (5)

• Multiple sites

• As many seeds/transplants as possible

• Planting individuals over several successive years at the same site

• Success: self-maintaining or growing pop

• Monitoring: often translocations fail several years later: < 33% success rate in plants

What factors create a "Misuse of reintroductions" (3)

• Proposals to create new habitat or new populations to compensate for habitat damage or eradication of endangered spp that occurred during development projects

• Poor success rate re: reintroductions and creation of habitat, so should protect existing pops

• Reintroductions not an alternative to protection of existing spp, but an additional tool

Ex-Situ Facility Zoos benefits and drawbacks (4)

• Establish viable, long-term captive breeding populations of rare & endangered spp

• Often charismatic vertebrates, but more variety now

• Provide info about ecology and threats

• Links between zoos and conservation efforts in the wild, research, education (600 million visitors/year

Captive breeding methods and targets

• Knowledge and experience re: animal care, vet medicine, animal behaviour, reproductive biology, and genetics

• Extensive research on animals that don't breed well in captivity e.g., rhinos

• Techniques to enhance low reproductive rate

What is Embryo transfer and when is it used (3)

• Cloning & cross-species hybridization

• Genome resource banks (eggs, sperm, embryos, tissues) e.g., Frozen Ark

• De-extinction

Limits of ex situ conservation (6)

*Expensive, especially for large mammals

• Population size often small (inbreeding/drift/nonrepresentative genetic variation)

• Adaptation to captivity

• Behaviour

• Continuity & funding

• Concentration of animals

• Surplus animals e.g,. monkeys

What are some Ethical Issues with Ex-situ conservations (5)

• Technological solutions to problems caused by human activity

• How will the wild population really benefit?

• Are captive-bred individuals that can't survive in the wild really a success?

• Do spp held in captivity benefit or is it really the economic benefit to the zoo/pleasure of zoo visitors?

• Receiving appropriate care? Do the benefits to the spp outweigh the costs to the individuals?

• Is sufficient effort made to educate the public?

Aquariums and Ex-Situ: Importance and drawbacks (4)

• Unusual and attractive fish, performances by marine mammals

- many of the same concerns re: zoos

• Conservation a major educational theme, advice about sustainable seafood

• Important b/c so many fish in trouble

• 600,000 fish maintained in public aquariums, most obtained from the wild

• Efforts to develop breeding techniques for rare spp for later release back to the wild

• Early stage but info from hatcheries and the aquarium trade

Botanical gardens and arboretums: Benefits (4)

• Display, but also plant propagation

• 1,775 botanical gardens with crucial resources for plant conservation

• 4 million living plants & 80,000 spp (30% of the world's flora)

• Now focus efforts on rare/endangered spp, and many specialize

Why is Ex-situ conservation easier with plants? (5)

- Propagation

- Needs may be met in greenhouses

- Kept outdoors

- Often produce seed readily, which can be banked, sometimes for decades

- Botanic garden staff are often authorities on plant ID, distribution and conservation

- Conservation efforts coordinated by:

What are Seed Banks and how are they used in conservation (3)

• Collections of seeds formerly focused on cultivated plants but now a wider range of spp

• Can be stored in cool dry conditions for a long time

• Very well suited to ex situ conservation b/c large numbers of rare spp can be stored with little cost & supervision

Who Coordinates seed banks

• Consultative Group on International Agricultural Research and the International Board for Plant Genetic Resources coordinate agricultural seed banks

- International Rice Institute (Philippines)

- International Maize and Wheat Improvement Center (Mexico)

- National Germplasm System (Geneva, NY)

Sampling Strategies for seed banks (3)

- 5 populations from each sp

- 10-50 individuals from each pop

- Care re: wild pop (don't take all the seeds!)

Seed Bank Storage Issues (5)

- Power

- Ability to germinate (germinate, grow, pollinate, store new seeds)

- difficult for large collections and large plants

• About 10% spp have seeds lack dormancy or can't be stored (cocoa, rubber) - must germinate or die: store the embryo or young seedling

• Root crops (often no seeds): vegetative propagation e.g., International Potato Center (Peru) & International Center for Tropical Agriculture (Colombia)

Seed savers and crop varieties

• Seed Savers Exchange in Iowa preserves heirloom varieties of crop plants brought to N. Am. by settlers

• In 37 years, SSE has organized 700 gardeners and plant breeders to preserve 12,000 varieties, which are offered in the SSE catalogue

• Many varieties only offered by a single grower responsible for curating that variety

• Interesting/long histories, unusual colors/flavors, and genetic diversity

Genetic resources of trees: Sources and considerations (5)

• Forestry

• Relying on wild-collected seeds problematic because superior trees often logged

• Results of poor seed selection only seen years/decades later

• Foresters use cuttings and families of closely related seeds taken from the best trees to establish plantations called clone banks

• 8000 clones of loblolly pine in SE US - selected trees used to establish seed orchards for commercial seed (seed storage is difficult)

• Preserving areas where trees grow naturally is important for genetic diversity

Convention on Biological Diversity

• Aims to create fairness (170 countries signed on)

- Countries have the right to control access to their biological diversity and should be paid for its use

- Countries have a responsibility to inventory and protect their biological diversity

- Collectors must have permission to collect samples from the host country, the local community and the landowners

- Where possible, research, breeding, processing and production of new varieties should take place in the countries where the resources occur

- Financial benefits of new products and varieties should be shared with countries that contributed the genetic resources

- Legal framework being developed, Brazil taking the lead

What are Protected Areas (2)

• Clearly defined geographical space, recognized, dedicated and managed through legal or other means to achieve long-term conservation of nature with associated ecosystem services and cultural values

• Can prohibit or allow access/activities that are compatible with conservation

United Nations Educational, Scientific & Cultural Organization (UNESCO)

Specialized agency of the United Nations, established in 1945

International Union for the Conservation of Nature and Natural Resources (IUCN)

UNESCO's first Director General, Sir Julian Huxley, helped establish this institution in 1948 to give UNESCO a scientific basis

Describe some attributes of Existing Protected Areas (4)

• Large countries with rich biotas and a variety of ecosystem types benefit from having many protected areas

• Almost all countries have at least 1

• Approx 160 000 protected areas exist in IUCN categories I-VI, covering 30 million km2 on land and 2 million km2 at sea

• About 13% of the Earth's surface (same as the area used to grow crops)

• Unique areas that are economically important often remain unprotected

What are the goals of Marine Protected Areas and how prevalent are they (2)

• Preserve nursery grounds, maintain water quality, and physical/biological features of the ecosystem (rec activities often preserved too)

• About 6% of territorial seas near coastline and 2% of the total marine environment are protected

• ~5,000 marine and coastal protected areas worldwide

"Rocks & Ice Syndrome" (1)

(protected areas are often a biased subset of habitats - those that are not desirable for other purposes)

What factors affect the Efficacy of Protective areas (4)

• Generally effective when regulations are

enforced or when the area is isolated

• Obvious differences in biodiversity within

park boundaries for tropical areas

• provide income and services to poor

people living nearby

•established and maintained where concentrations of spp

occur,

• If system includes representatives of all major ecosystems, can protect a lot of spp

Louisiana State Forests

Alexander State Forest & Indian Creek Recreation Area

Louisiana State Wildlife Management Areas

Sandy Hollow WMA

Louisiana State Department of Culture, Recreation & Tourism

Poverty Point World Heritage Site

What are the goals of the Aichi Biodiversity Target (2)

aim to protect 17% of terrestrial and inland water areas and 10% of coastal and marine areas by 2020

Common mechanisms to establish Protected areas (3)

- Government action (usually national but sometimes regional)

- Land purchases and easements by individuals and conservation organizations

- Actions of indigenous and traditional peoples

Steps to Establishing a new Protected Areas (3)

1. Establishing priorities for conservation

2. Identifying high priority areas that should be

protected

3. Choosing new PAs by filling gaps and developing

networks

1) Establishing Conservation Priorities

• What needs to be protected?

• Where should it be protected?

• How should it be protected?

• Three criteria often used to answer the first two questions

- Distinctiveness

- Endangerment

- Utility

Distinctiveness (2)

(irreplaceability): an ecosystem with rare, endemic spp or unique attributes is given higher value - evolutionary distinctiveness & unusual genetic characteristics also important

Endangerment (2)

spp in danger of extinction, ecosystems in danger of destruction - measured as present size of geographic range, rate of decline in range, loss of ecological function

Utility (2)

spp with present or future value to people more highly valued e.g., wild relatives of wheat, cultural significance, coastal wetlands

2) Identifying Areas to Protect

• Three criteria for prioritization systems to

target spp & ecosystems - generally

complementary

- Species Approach

- Hotspot Approach

- Ecosystem Approach

• Re-evaluate in light of climate change b/c spp

& ecosystems may not survive in their current

locations

Species Approach to PA

• Species that provide an impetus to protect an area and ecosystems

• Types of focal species

- Indicator spp: associated with an endangered biological community or set of unique

ecosystem processes: N. Spotted Owl, RCW

- Flagship spp: capture public attention, have symbolic value, and are crucial to ecotourism

- Indicator and flagship spp whose protection automatically extends protection of other spp and its biological community

• Depends on survival plans to identify

areas of high conservation value

What is the Hotspot Approach (1)

• Protect areas with high levels of spp richness

• Some organisms or groups of organisms can be used as

biodiversity indicators when data about whole

ecosystems are lacking

What is the Ecosystem Approach

• Ecosystems targeted for conservation

• Spending $1 million on habitat protection might preserve more spp and provide more value to people in the long run than spending that amount on one sp

- Also easier to demonstrate to policy makers and the public the economic value of ecosystems re: flood control, clean water, and recreation

• Protect representative sites of as many types as possible

What are Wilderness Areas and how are they different from Protected areass (2)

• High priority for protection: large tracts are distinct and endangered

• But most places have been affected by humans

• Probably the only places on Earth where natural processes still occur without human interference e.g., natural disturbances (forest fires, insect outbreaks) and animal migration (e.g., salmon and caribou)

• Boreal forest

3 Tropical wilderness areas

- South America: wilderness arc southern Guianas/Venezuela and northern Brazil, Colombia, Ecuador, Peru & Bolivia - roads & consequent logging, migration and ag

- New Guinea - logging, plantation ag, human pop, roads

- Congo Basin in Africa - warfare and lack of government control prevent conservation and development - road

Selecting new PAs: filling gaps & creating networks

• Once a high priority area identified, need to consider:

- Sites not already protected

- Sites that maximize linkages to create networks

- Locations where the creation of a PA is practical and cost-effective

- Ensure that investment towards protection is spread adequately and not concentrated on a small number of areas

What is Gap analysis and what does it investigate (5)

- Data compiled on distribution/presence of spp,

ecosystems, and physical features: conservation units

- Conservation and social goals are identified: area and #

of individuals to protect, wilderness vs mixed resource mgmt

- Existing areas reviewed to determine what is already protected and what isn't

- Areas identified to meet goals (gap filling)

- Reviewed in detail and then protected & managed

- Monitored to see if meeting goals

Conservation Planning Software

• Uses algorithms to sort through data and identify gaps/create optimal designs for PAs

• A key feature is that it identifies the most cost-effective strategy and determines the amount of habitat that can be protected given a budget

• Used to help design expansion of no-take areas in Aus's Great Barrier Reef

What are Habitat corridors (3)

facilitate dispersal, gene flow, colonization

Width depends on spp and length of the corridor

Roads often an obstruction to habitat corridors

Drawbacks to Corridors (4)

• May facilitate movement of pest spp and disease

• Animals using corridors may be more vulnerable to depredation

• Can be expensive - buy more land elsewhere?

• Some studies show they are important, others do not

What is Landscape ecology and park design and what are their goals (3)

• Landscape ecology investigates patterns of the physical environment, ecological communities, ecosystem processes, and human-ecosystem interactions

• A landscape is a repeating pattern of landforms or ecosystems, with each type of ecosystem having its own veg structure and spp composition

• Protecting biodiversity occurs in a landscape context

• Many spp move between habitats or live on borders

where two habitats meet - patterns of habitat types

are critical

• Species presence and density will be affected by the

size of the habitat patch and their degree of linkag

What factors are considered when Managing protected Areas (6)

- Prevent degradation

- Protect biodiversity

- Maintain ecosystem services& health

- Maintain historical landscapes

- Provide resources and experiences of value to people

- Consider ecology and ecological succession

What are Failed management actions and name some examples (4)

• Practices may be ineffective or

detrimental

• Examples

- Areas managed to protect game species like deer

• Predators removed - overgrazing, habitat degradation, collapse of animal/plant communities

- Parks with visitors or timber harvesting may remove snags, rotten logs and underbrush - needed nesting/overwintering sites for some spp

- Fire may be part of the natural ecology but is suppressed - expensive and loss of fire-dependent spp