Conservation Biology Exam 3

extinct

no member of the species remains alive anywhere in the world

Locally extinct

no longer found in an area that individuals once inhabited

ecologically extinct

numbers of the populations are reduced to a point where its effect on other species in the community are negligible

extinct in the wild

individuals of a species remain alive only in captivity

globally extinct

extinct in the wild throughout the world

five reasons a species is most vulnerable to extinction

-Species that have a very narrow range

-species with only one or a few populations

-small population size

-population decline

-hunted or harvested by people

endemic species

species naturally found only in a single geographic area

extinction rates in water

appear to be low, but likely an underestimate

four traits of metapopulations

-suitable habitat occurs in discrete patches that may be occupied by local breeding pops

-even the largest populations have a significant risk of extinction

-habitat patches must not be too isolated to prevent recolonization after local extinction

-the dynamics of local populations are not synchronized

Why are metapopulations important

balance between colonization and extinction

two important phenomena prevent habitat fragments from conforming to island biogeography theory

-habitat diversity may be more important than area

-formation of habitat fragments create an edge effect

edge effect

change in physical and biological characteristics of a habitat as one move from the edge to the interior

10 categories of species closely linked with extinction

-species that need a large home range

-species with large body size

-not effective dispersers

-seasonal migrants

-little genetic variability

-specialized niche requirements

-characteristically found in stable, pristine environments

- form permanent or temporary aggregations

-no prior contact with people

-closely related to other species that have gone or threatened with extinction

U.S. Endangered Species Act of 1973

provide a means whereby the ecosystem upon which endangered and threatened species depend may be conserves to provide a program for conservation of such species

threats to biodiversity

habitat destruction

habitat fragmentation

habitat degradation and pollution

100 million/year is the estimated growth of the human population

more people = less biodiversity

urbanization

habitat destruction and pollution

agriculture

habitat loss

desertification

habitats degraded into man-made deserts

why is desertification bad

not functional desert ecosystems

soil erosion

loss of water capacity of soil

examples of habitat loss

-mining

-dynamite fishing

-deforestation

coral reefs

20% of all coral reefs have been lost

habitat fragmentation

large areas of continuous habitat is reduced in area creating fragments of the habitat

Consequences of habitat fragmentation

1. certain species may not have enough space to live and breed

2. potential for dispersal and colonization often reduced

3. reduces foraging ability of animals

4. population decline and extinction rate increases

5. changes in microclimate, interspecific interactions, fire, and disease

pesticide pollution

described biomagnification-chemicals move through the food chain becoming more concentrated at each level

oil spills

birds, marine mammals, and ocean animals sicken and die

costal hypoxia

high nitrogen and phosphorus levels from human activity resulted in excessive algae growth, death, then decay resulting in such low levels of oxygen that the fish died

acid rain

rain with lower pH, leads to the death of trees over large expanses

ghost nets

discarded nets catch fish, marine mammals and reptiles causing suffocation

plastic bags

small pilot whale unable to swim and vomiting plastic bags. Found 80 plastic bags weighing 7.7 kg

eutrophication

human waste, agricultural fertilizers, detergents, and industrial processes often release large amounts of nitrates and phosphates into aquatic ecosystems

soil

when introduced into waterways it can make aquatic ecosystems inhospitable to some species of gill-breathing organisms, causing them to suffocate

source population

patch that provides net donation of immigrants to nearby patches with lower-quality habitat

sink population

patch that would go extinct if it were not for the constant input of immagrants from nearby source population

Immigration

IN

Emmigration

EXIT

conservation

must think about present and future distribution when making protected areas

exploitive threats to biodiversity

- overexploitation of species for human use

- introduction of exotic species

- increased spread of disease

Pangolin

all eight species are protected under international and national laws, and two are listed as CE on IUCN. Over harvested due to meat and scales

social dilemmas

pay off matrix

tragedy of the commons

unless environmental costs are accounted for and addressed in land use practices the land will be unable to support activity

generational conservation

harvesting intensity has decreased over the years

solutions to overexploitation

- link conservation of biodiversity with local economic development

- establish protected natural areas where species are overexploited

- strict and enforced laws regulating hunting and harvesting

stakeholder participation

satisfaction

- why do people become engage in wildlife-use activities?

- why do they continue or stop participating?

- how can participation be influenced?

invasive species

- species that

increase in abundance at the expense of native species

- often exotic species

invasive exotic species

threaten about 4o% of endangered species in USA

water hyacinth

invasive species that covers ponds and lakes, limiting photosynthesis and lowering oxygen levels in the water

biological introductions

- purposeful introductions that got out of control. i.e. kudzu

- GMOs

GMO hope

crops will produce more food and use less pesticides, resulting in an improved water quality and healthier animals

GMO fear

crops will harm birds, insects, soil organisms, other species, and even humans

sink population