Chapter 56 - Conservation Biology

Biodiversity Levels Human activities are threatening the Earth’s Biodiversity Genetic Diversity – genetic variation within a population and between populations Species Diversity Ecosystem Diversity

A Hundred Heartbeats Club Harvard Biologist E.O. Wilson Organisms that have fewer than 100 individuals left on Earth Also a 2009 book by Jeff Corwin The Red List

Why should we care? Aside from human connection to nature, there are practical benefits as well Could lose valuable crops, fibers, and medicines for human use Ecosystem services – support human existence Purification of air and water Fertile soils Detox and decompose wastes Pollination of crops Dispersal of seeds Cycling of nutrients Control agricultural pests Protect from erosion and ultraviolet rays Moderation of weather Rosy periwinkle – contains alkaloids that inhibit cancer cell growth

Svalbard Global Seed Vault To provide insurance against both incremental and catastrophic loss of crop diversity. Currently 781,148 records on file(741,493 last year) and 513,801,025 seeds http://www.nordgen.org/sgsv/

Major Threats to Biodiversity Habitat destruction by agriculture, urban development, forestry, mining, and pollution; accounts for 73% of species that have become extinct, endangered, vulnerable, or rare during modern history; 93% of coral reefs Introduced species (invasive, nonnative, or exotic) – usually free from predators, parasites, and pathogens that can limit population growth; examples include zebra mussels, kudzu plant, African honeybee, snakehead fish, and stink bugs! Overexploitation – harvesting species at rates that exceed their ability to rebound; over fishing Disruption of interaction networks – keystone species, pollinators

Population Conservation Attempting to conserve populations and species and prevent extinction Small-population approach – population drops below minimal viable population (MVP) size, loses genetic variation, trapped in an extinction vortex; genetic emphasis Declining-population approach – focus on environmental factors regardless of pop size, such as loss of habitat

Species Diversity Crisis Endangered Species – in danger of extinction throughout all or a significant portion of its range Threatened species – likely to become endangered in foreseeable future 12% of 10,000 known species of birds and 21% of 5,500 known species of mammals are threatened Nearly 1000 of 20,000 known plant species in US are either extinct, endangered or threatened 21% of known freshwater fishes have either become extinct or are threatened 32% of known amphibian species and 21% of known reptiles are near extinction or are endangered Estimates show that at current rates of extinction, more than half of all currently living plants and animals will be extinct by the end of the 21st century Source: International Union for Conservation of Nature and Natural Resources (IUCN) and Cener for Plant Conservation. www.biologicaldiversity.org

Landscape and Regional Conservation Focus on saving entire communities, ecosystems and landscapes as compared to individual species Establish protected areas – usually in a biodiversity “hot spot” (relatively small area with a large concentration of endangered and threatened species), most impacted biomes are rainforest and chaparral Set up nature reserves – example of grizzly bears in Yellowstone