Global Change and a Sustainable Future Chapter 18

Mass Extinction Biodiversity a. instrumental and intrinsic value Extinctions a. “last member of the species dies” b. 5 major - 50,000 species extinctions/yr (0.5%) c. now experiencing the 6th - human cause Instrumental – food, medicine, building materials, regulating services (plants removing CO2) Intrinsic – no direct benefit to people but they are valuable to us and we need to preserve them

Global Declines in Genetic Diversity Wild Organisms a. prone to inbreeding depression - produces impaired offspring b. natural causes v. human causes Natural causes – bottleneck effect Human causes – eradication of predators

Crops and Livestock a. producers have started concentrating on breeds that are most productive resulting in lower genetic variation b. forces breeds to become endangered

Global Decline in Species Diversity Status of species a. Data deficient – no reliable data to assess b. extinct – no longer exist since 1500 c. threatened – high risk of extinction d. near-threatened – very likely to become threatened e. least concern – very widespread species

Since 1500 a. birds - 10,000 existed, 133 extinct, 21% threatened b. mammals - 5,500 existed, 79 extinct, 25% threatened c. amphibians - 6,200 existed, 39 extinct, 49% threatened

Causes of Declining Biodiversity Habitat Loss a. greatest cause of decline ex) northern spotted owl - old growth forests The old trees have been removed for lumber and housing developments and it has completely transformed the old tree forest into a different habitat and it has reduced the number of spotted owls.

a. native species – native to the land b. alien/exotic species Alien Species a. native species – native to the land b. alien/exotic species - species living outside of their normal range - introduced accidentally or intentionally c. invasive species - no natural enemies - 2 most common in North America * Kudzu vine * Zebra Mussel - act as predators, pathogens, competitors to native species Accidentally – rats that stow away in packaging containers, pests that are on packaging containers Intentional – exotic plants being sold in greenhouses or for outdoor landscape Some alien species are not a threat and have no negative effect, but if they spread rapidly, they are known as invasive species Kudzu - native to Japan and Southeast China and was introduced to the United States in 1876 - we were encouraged to plant kudzu to help reduce erosion in our fields - herbivores did not eat the kudzu so it spread very rapidly and taking over most flowers and creating too much shade for the trees Zebra Mussel - native to the Black Sea and Caspian Sea in Asia - large cargo ships that traveled in these seas unloaded their cargo in Asian ports and then pumped water into their storage tanks to make sure the ship would sit low enough to remain stable - but they started just loading on new cargo and no longer needed the water to put on the boat so they pumped it back into local waters resulting in a increase of zebra mussels - positive * remove large amounts of algae and contaminants - negative * physically crowd out many native mussel species and may consume too much algae

Overharvesting a. removed faster than population can replace themselves – can cause extinction b. Dodo bird, sloths, mammoths c. poaching d. regulations - state and federal restrict hunting/fishing of game animals to particular times of the year and limit the number that can be harvested

Pollution a. pesticides, heavy metals, oil spills, endocrine disruptors (reproduction), release of nutrients (N and P), thermal pollution (cooling of power plants) Climate Change a. changes in patterns of temperature and precipitation in different regions of the world and how it will affect the organisms

Conserving Biodiversity Two general approaches a. single species approach b. ecosystem approach

Single Species Approach a. focuses on one species at a time b. approach 1. encourage population rebound - improving living conditions - providing additional habitat - reducing contaminants - captive breeding (California Condor)

c. legislation 1. Marine Mammal Protection Act - prohibits killing of all marine mammals in the US and prohibits the import/export of an marine mammal body parts - exceptions can only be made through: * US Fish and Wildlife Service * National Marine Fisheries

2. Endangered Species Act (1973) - authorizes US Fish and Wildlife service to determine which species can be listed as threatened/endangered - prohibits the harming of the listed species as well as trade of species - authorizes govnt to purchase habitat for species - listed species * 201 invertebrate * 795 plants * 381 vertebrate

3. Convention of Biological Diversity - international treaty - 3 objectives * conserve biodiversity * sustainably use biodiversity * equitably share the benefits that arise from commercial use of genetic resources

Ecosystem Approach a. preserves particular regions (biodiversity hotspots) – national parks, marine reserves b. Factors to consider 1. size and shape of protected area 2. connectedness to other protected areas 3. recognize how to incorporate conservation while seeing the need for sustainable habitat use for human needs

c. Island Biogeography applied to protected areas 1 c. Island Biogeography applied to protected areas 1. distance between areas - further apart, harder for species to travel among them 2. metapopulations 3. edge habitat - where two different communities come together Metapopulations – collection of smaller populations connected by occassional dispersal of individuasl along habitat corridors