Chapter 12

Local- species is no longer found in an area it once inhabited

Ecological- numbers of species are so few that it can no longer play its ecological roles in biological communities

Biological- species is no longer found anywhere on Earth (forever)

Extinctions

Endangered- so few individual survivors that species could become extinct

Threatened- abundant in natural range but declining numbers & likely to become endangered

Endangered VS. Threatened

Characteristic ExamplesLow reproductive rate(K-strategist)

Specialized niche

Narrow distribution

Feeds at high trophic level

Fixed migratory patterns

Rare

Commercially valuable

Large territories

Blue whale, giant panda,rhinoceros

Blue whale, giant panda,Everglades kite

Many island species,elephant seal, desert pupfish

Bengal tiger, bald eagle,grizzly bear

Blue whale, whooping crane,sea turtles

Many island species,African violet, some orchids

Snow leopard, tiger, elephant, rhinoceros, rare plants and birds

California condor, grizzly bear, Florida panther

Vulnerable to extinction

0.1 to 1% per year

1,000 to 10,000 times higher than prior to humans

Extinction Rates

Rate of species loss & the extent of biodiversity loss are likely to increase in next 50-100 years due to human population growth

Current & projected extinction rates are much higher than global average in endangered centers of biodiversity

Humans are eliminating degrading & simplifying many biologically diverse environments

Rates

It will take at least 5 million years for speciation to rebuild the biodiversity we are likely to destroy during this century.

Intrinsic value- (existence) inherent right to exist & play its ecological role regardless of its usefulness to us

Biophilia- love of life

Why?

Habitat loss

Habitat degradation and fragmentation

Introducing nonnative species

Overfishing

Climate change

Predator and pest control

Pollution

Commercial hunting and poaching

Sale of exotic pets and decorative plants

•Population growth•Rising resource use•No environmental accounting•Poverty

Secondary Causes

Basic Causes

Causes of Reduction of populations

Habitat disturbance – agriculture, commercial development, water development, outdoor recreation, livestock grazing, pollution

Indian tiger, Black rhino, African & Asian/Indian elephant

Premature Extinctions

Habitat fragmentation - large, continuous area of habitat is reduced in area & divided into small scattered, isolated spots

(Deliberate) Nonnative species- used as biological control; no natural predators, competitors, parasites, or pathogens to help controls numbers; wipe out native species, disrupt ecosystems & cause large economic losses

Figure 12-9b Page 235

Sea lamprey(attached to lake trout)

Argentina fire ant Eurasian muffleBrown tree snake Common pigeon(Rock dove)

Formosan termite Zebra mussel Asian long-hornedbeetle

Asian tiger mosquitoGypsy moth larvae

Accidentally introduced Species

(Accidental) Nonnative species- arrive as stowaways on aircraft, tankers, cargo ships; no natural predators allow rapid spreading

Poaching- killed for valuable parts or sold to collectors; increases chances of premature extinction Mountain gorilla (live), panda pelt,

chimpanzee, Imperial Amazon macaw, rhinoceros horn

Figure 12-9aPage 235

Purple looselife European starling African honeybee(“Killer bee”)

Nutria Salt cedar(Tamarisk)

Marine toad Water hyacinth Japanese beetle Hydrilla European wild boar(Feral pig)

Deliberately introduced Species

Predator & pest control- people exterminate species that compete with them for food & game animals Elephants, prairie dogs, wolves, bobcats,

coyotes Exotic & decorative- profitable

Exotic birds (macaw), amphibians, reptiles, mammals, tropical fish

Climate change & pollution- human activities bring a rapid climate change Polar habitats Pesticides- honey bees, birds, fish

Decline in population – 70% 1 in 6 bird species – threatened with

extinction

Environmental Condition Indicator1. Live in every climate & biome2. Respond quickly to environmental changes to

habitats3. Easy to track & count

Birds

Characteristics of

Successful Invader Species

• High reproductive rate, short generation time (r-selected species)

• Pioneer species

• Long lived

• High dispersal rate

• Release growth- inhibiting chemicals into soil

• Generalists

• High genetic variability

Characteristics ofEcosystems Vulnerable

to Invader Species

• Similar climate to habitat of invader

• Absence of predators on invading species

• Early successional systems

• Low diversity of native species

• Absence of fire

• Disturbed by human activities

Figure 12-12Page 238

1. Identify characteristics that allow species to become successful invaders & vulnerable ecosystems

2. Inspect imported goods that may contain invaders

3. Identify harmful invader species & pass laws banning transfer

4. Prevention & control

Reducing the Threat

Convention on International Trade in Endangered Species

Restrictions on species that cannot be traded or sold (over 30,000 species)

Difficult to enforce Enforcement varies from country to country Highly profitable trade occurs in countries

that did not sign treaty

CITES

Endangered Species Act Designed to identify & legally protect

endangered species in US & abroad Americans cannot sell or buy products made

from these animals

ESA

Habitat Conservation Plans Landowners, developers, loggers allowed to

destroy part of endangered or threatened species population on private land in exchange for taking steps to protect the species

HCPs

Landowners voluntarily agree to take specified steps to restore, improve, or maintain habitat for threatened or endangered species located on their land

Safe Harbor Agreements

Landowners agree to take steps to help conserve a species whose population is declining

***All 3 are designed to be a compromise between private landowners & interest of endangered & threatened species

Voluntary Candidate Conservation Agreements

Landowner Compensation

Advantages- Disadvantages- cost, hinders passage of new land use, environmental, health, & safety laws

Expensive failure Only 37 species have been removed from

this list 14 recovered 8 extinctions Others removed due to technical errors or

discovery of new populations

ESA

Serve as a vital wetland sanctuary for migratory waterfowl

Some set aside for specific endangered species

Bad news- 60% of activities that are harmful to wildlife occur within refuges; invasions by nonnative species; too much hunting/fishing & use of powerboats & off-road vehicles cause damage

Wildlife Refuge

Preserves genetic info & endangered plant species by storing seeds in refrigerated, low-humidity environment; store wide range of threatened species & genetic diversity

Bad news- expensive to operate; destroyed by accidents; prevents evolution

Gene Bank

Arboretums Contain living plants; educates million of

visitors Bad news- too little capacity; too little

funding

Botanical Gardens

Used to preserve some individuals of critically endangered species with long-term goal of reintroducing the species into protected wild habitats

Egg pulling- collecting wild eggs laid by critically endangered bird species & hatch in zoos or research centers

Captive breeding- wild individuals are captured for breeding with aim of reintroducing offspring into the wild

Zoos

Bad news- lack of space & money; major role needs to be education

Exhibits unusual & attractive fish & marine animals; education to public about need for protection; not an effective gene bank

Bad news- considered a prison; fosters the false notion that preserving small numbers is useful

Aquarium

Science of inventing, establishing, & maintaining new habitats to conserve species diversity in places where people live, work, play

Examples Butterfly habitat- 20+ neighbors provide self-

sustaining habitat would attract birds or bat-eating insects

Safe harbor agreements- bluebirds- nest boxes

Reconciliation Ecology