Term
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Definition
provide data on the numbers, ages, sexes, conditions, and locations of individuals withing a population.
Indicate stability of population |
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Term
| Parameters determining how populations change over time |
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Definition
| BIDE Equation: Births + Immigration - Deaths - Emmigration |
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Term
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Definition
Rate of change over time: N(t+1) / N(t)
>1 - population increasing
=1 - stable population
<1 - declining population |
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Term
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Definition
| changes in pop due to factors that are predictable. Ex) habitat change |
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Term
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Definition
causes changes in pop by factors that are not predictable. Ex) weather, food supplies, genetic changes, disease, predators.
4 kinds |
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Term
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Definition
Unpredictable changes in pop due to changes in genetics. Ex) Changes caused by inbreeding, inbreeding depression
Case study: Florida Panther |
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Term
| Demographic stochasticity |
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Definition
| Unpredictable changes in pop due to random nature of population make-up: sex ratios, survival, reproduction. Causes less of an effect as population gets larger. |
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Term
| Environmental stochasticity |
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Definition
Unpredictable changes in pop due to environmental factors like weather, food supply, disease, predators, etc.
Case study: Marbled Murrelet |
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Term
| Catastrophe stochasticity |
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Definition
| Extreme unpredictable events like fire, floods, intense storms or droughts. Have a large impact on many individuals. |
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Term
| Population size and rise of extinction from stochastic factors |
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Definition
| As pop size gets bigger, stoch. factors have less of an effect on prob of extinction. Environmental is a straight downward diagonal line. Dem & Genetic level off quickly with more individuals. Catastrophes play a part until pop gets really big, and then levels off. |
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Term
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Definition
| Populations can be positively or negatively affected by the density of their populations. Neg when pop is too big and there's not enough resources to go around. Pos when pop is small and there's not enough genetic diversity. |
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Term
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Definition
| assemblage of discrete local populations, connected by immigration and emmigration |
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Definition
| A distinct set of individuals with high degree/probability of interaction |
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Definition
| area in which a local population lives |
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Term
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Definition
| area surrounding patches that are unsuitable habitat |
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Term
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Definition
| Loss of individuals from an occupied patch |
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Term
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Definition
| Immigration of new individuals into an unoccupied patch |
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Term
| Population viability analysis |
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Definition
| quantitatively predicting the likely future status of a population or collection of populations. |
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Term
| Minimum viable population |
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Definition
| smallest population that has less than the probability of extinction for a given period of time |
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Term
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Definition
Need population numbers, historical data, pop growth rate, and effects of stochasticity.
Project the pop forward in time by: growth rate x population size + stochastic factors.
Projections diverge with time for different populations. Stochasticity increases the likelihood of extinction. |
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Term
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Definition
Plagued by uncertainty, in extinction risk and minimum viable pop assessment.
Uncertain in BIDE estimates, effect of stochastic factors, importance of density dependence, effect of inbreeding depression, unpredictable future conditions, inability to test predictions. |
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Term
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Definition
50 ind needed in the short term to balance increased homozygosity with natural selection
500 ind needed in long-term to balance genetic loss from genetic drift with new random mutations |
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Term
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Definition
Extreme risk of extinction in immediate future.
50% extinction in 10 years. |
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Term
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Definition
High risk of extinction in the wild in the near future.
20% extinction in 20 years. |
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Term
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Definition
High risk of extinction in the medium-term future.
10% extinction in 100 years. |
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Term
| Five approaches for diagnosing causes of population decline. |
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Definition
Experimentation - change factors & see how demographics change
Population comparisons
Species life-history comparisons
Timing of decline - compare environmental factors before & after decline
Multiple competing hypotheses - competing predictions of which environmental factors are to blame, all backed-up with field data |
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Term
| Population comparison: Trout & Yellow-legged frogs |
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Definition
Did the introduction of Rainbow trout negatively affect Yellow-legged frogs?
Survey lakes & different populations. Found that there were many more frogs when fish were absent. Easy to solve: remove fish populations from some lakes. |
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Term
| Timing of decline approach: Amphibian decline in Costa Rica cloud forest. |
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Definition
What were environmental conditions before/during/after the decline?
Found that increasing number of dry days in dry season lead to more decline in amphibians. Reduced frog habitat also lead to more dense pops and increased disease. |
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Term
| Species life-history comparisons: decline of songbirds in NA |
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Definition
| Found that spp that were ground nesters were more susceptible to predation than forest-dwellers. They had lower growth rates. |
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Term
| Factors limiting Marbles Murrelet reproduction |
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Definition
| Increased Common Raven populations, disappearing old growth forests, warmer temperatures. Marbled Murrelet is federally threatened. |
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Term
| Measuring Marbled Murrelet reproductive success |
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Definition
Go to sea at night, shine light and catch birds. Reproductive success = Juvenile to adult ratio: #J/#A
Tagged birds. Followed them to nestsites in planes. Nested in Santa Cruz Mountains. Nest in old-growth forests near streams, but only in unharvested stands.
Even though the proportion of # of breeders were increasing in Murrelet populations, nest success rates continued to be low due to predation by corvids (ravens).
PVA showed that by managing corvids, the proportion of of murrelet nests would increase which would decrease the probability of extinction. |
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Term
| Conservation of endangered spp and the bottleneck effect |
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Definition
| Immediate goal is to increase population size immediately to avoid bottleneck effect. Then treat real problems after population stabilizes. |
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Term
| Ultimate causes of endangerment |
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Definition
Changes in the environment that underlie spp endangerment - habitat loss, exotic spp, overkill, pollution, climate change.
Hard to correct in time to save spp, but need to be corrected eventually to guarantee continued future success. |
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Term
| Proximate causes of endangerment |
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Definition
Obvious problems populations are showing but not the root problems - decreasing survival, lowered reproduction, declining numbers, shrinking range.
Can be treated independently of big, ultimate causes. By treating, allows pops to make it through crisis while root causes are being resolved. |
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Term
| Ways to stimulate rapid population growth |
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Definition
Reduce mortality factors
Increase reproduction
Translocate individuals (to increase pool, move individuals around to better areas, and reduce inbreeding) |
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Term
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Definition
Reduce impacts of predators, poaching, competitors and diseases. Without these losses, pop growth is stimulated.
Ex) Black Rhino -- dehorn rhinos so that poaching value is taken away.
Ex) Japanese crane -- increased over-winter survival by artificial feeding.
Ex) White-tailed Eagle -- diseased/polluted food was decreasing population, so supplemented diet with clean carcasses. |
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Term
| How to increase reproduction |
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Definition
Even if reproduction rate isn't the problem, raising it can help stabilize a population. Enhance breeding sites, control predators, and/or supplement feeding.
Ex) Bermuda Petrel -- rats/cats pushed petrels to offshore island where there were bigger birds outcompeting them for nests. Placed baffles at nest sites to gain advantage for petrels.
Ex) Puerto Rican Parrots -- manipulate nest sites to make them more suitable.
Ex) Kirtland's warbler -- Although declining due to fire suppression (habitat loss) more immediate problem was cowbirds. Trapped cowbirds so they wouldn't invade nests.
Ex) Vulture restaurants -- nestlings weren't getting enough calcium. Added fortified bone fragments to vulture restaurants so parents would pass on the nutrient. |
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Term
| Why translocate individuals |
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Definition
Increase breeding pool, remove ind from high-risk areas, reduce inbreeding.
Ex) Guam Rail -- brown tree snake threatens populations, so move to a snake-free, low-risk area insures survival.
Ex) Florida Panther -- translocated inds from another subspecies to help reduce inbreeding depression.
Ex) Bald Eagle -- NY down to last breeding pair due to DDT. Brought in ind from other productive populations to increase breeding pool. |
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Term
| If decision to begin recovery effort is made, how to decide what management options to undertake? |
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Definition
| PVA (population viability assessment) can test the future effectiveness of different management regimes on recovery and future viability. |
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Term
| Attributes that can be monitored when assessing the success of a management strategy. |
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Definition
Population size
Birth/survival rates, age/sex composition (demography)
Health of individuals
Level of threat
Environmental factors |
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Term
| When use captive breeding? |
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Definition
| When in-situ management is too challenging or impossible. When extinction is imminent, demographic/genetic problems that can easily be managed in captivity, or as insurance against the loss of a small pop |
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Term
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Definition
| Maintain the spp for a defined period of time in captivity. Produce enough ind to cover declining population and reintroduce into areas of extirpation. |
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Term
| International Species Inventory System (ISIS) |
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Definition
| Maintains database on captive populations, coordinates demographic and genetic management. |
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Term
| Advantages of Captive Breeding |
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Definition
Applicable to many species
Enhanced survival
Increased reproductive rates
Genetic/demographic management
Education potential |
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Term
| Enhanced survival due to captive breeding |
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Definition
| Organisms get good food, medication, protection from predators in confinement, thus live a long time. |
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Term
| Increased reproductive rates due to captive breeding |
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Definition
Variety of techniques:
Double clutching in birds -- remove first clutch from wild & parents produce another
Embryo transfers -- bongo calf birthed from eland surrogate mother. |
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Term
| Genetic/demographic management of captive bred individuals |
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Definition
Populations are managed via ISIS plans, can bring in new individuals or get ones with a certain genetic make-up.
Ex) The Kakapo |
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Term
| Educational opportunities due to captive breeding |
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Definition
| Captures the public's attention, information reaches a lot of people. |
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Term
| Disadvantages of captive breeding |
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Definition
Costly
Labor intensive
Limited facilities
Loss of "wild" behaviors, domestication
Detracts from in-situ management |
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Term
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Definition
Hard can result in high losses -- best for translocations
Soft sees improved survival but requires more effort and skill -- recommended for captive-bred ind |
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Term
| Pre-Endangered Species Act |
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Definition
Lacey Act (1900): illegal to transport illegally harvested animals across state lines.
Migratory Bird Conservation Act: protection for migratory birds from harvesting. Provided funding to purchase habitat for migratory birds.
Land/water conservation fund act: provided money to buy land & waters for preservation of fish/animals threatened by extinction. |
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Term
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Definition
Endangered Species Preservation Act: limited protection for andangered vertebrates.
Endangered Species Conservation Act: provided additional protection to spp in danger of worldwide extinctinon. Import/sale of such species became illegal.
Then congress found that many animal/plants have gone extinct due to economic growth. Many more are in danger and it is in the Nation's interest to conserve them. |
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Term
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Definition
| To preserve the ecosystems upon which threatened and endangered species depend, includes invertebrates, vertebrates, plants and animals. Also provides programs/plans for conservation. |
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Term
| Administration of the ESA |
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Definition
USFWS for terrestrial/freshwater spp
NMFS (national marine fisheries service) for marine
USGS Biological Resources division conducts research for USFWS
Management activities carried out by fed/state/non governmental groups. |
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Term
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Definition
| Classified as endangered when in danger of extinction in the foreseeable future in all/a significant part of range |
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Term
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Definition
| to those likely to become endangered in the forseeable future |
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Term
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Definition
Anyone can petition to list/delisted/consider/reclassified
-Present/threatened destruction/modification of habitat
-Overuse/overutilization of spp
-Disease/predation
-Inadequate existing regulatory mechanisms
-Other factors threatening continued extistence |
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Term
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Definition
| A subspecies of fish/wildlife/plants or a distinct population any species of vertebrate fish/wildlife which interbreeds when mature. |
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