Chapter 9

 Passenger pigeon hunted to extinction by 1900  Commercial hunters used a "stool pigeon”  Archeological record shows five mass extinctions  Human activities: hastening more extinctions?

 Degrading and destroying biodiversity in many parts of the world and these threats are increasing : 83% of the earth’s land surface  filling in wetlands, converting grasslands and forests to crop fields and urban areas  Species are becoming extinct 100 to 1,000 times faster than they were before modern humans arrived on the earth (the background rate), and by the end of this century, the extinction rate is expected to be 10,000 times the background rate.

 Human activity has disturbed at least half of the earth’s land surface ◦ Fills in wetlands ◦ Converts grasslands and forests to crop fields and urban areas  Degraded aquatic biodiversity

 continuous low level of extinction  extinction rate : expressed as a percentage or number of species that go extinct/per million species per year 1/1,000,000= or.0001% ( estimated extinction rate before humans came on the scene)

 Premature extinctions due to ◦ Habitat destruction ◦ Overhunting

 Conservative estimates of extinction = % ◦ Growth of human population will increase this loss ◦ Rates are higher where there are more endangered species ◦ Tropical forests and coral reefs, wetlands and estuaries—sites of new species—being destroyed  Speciation crisis

Fig. 9-2, p. 185 Passenger pigeon Great aukDodoGolden toadAepyornis (Madagascar)

Fig. 9-3, p. 186 Number of species existing Effects of a 0.1% extinction rate 5 million5,000 extinct per year 14 million 14,000 extinct per year 50 million 50,000 extinct per year 100 million 100,000 extinct per year Number of years until one million species are extinct

 Endangered species – has so individual survivors that the species could soon become extinct over all or most of it’s natural range  Threatened species - abundant in natural range, but numbers declining

Fig. 9-5, p. 188 Stepped Art Fixed migratory patterns Blue whale, whooping crane, sea turtle Feeds at high trophic level Bengal tiger, bald eagle, grizzly bear Narrow distribution Elephant seal, desert pupfish Commercially valuable Snow leopard, tiger, elephant, rhinoceros, rare plants and birds Low reproductive rate (K-strategist) Blue whale, giant panda, rhinoceros CharacteristicExamples Rare African violet, some orchids Large territories California condor, grizzly bear, Florida panther Specialized niche Blue whale, giant panda, Everglades kite

 Three problems ◦ Hard to document due to length of time ◦ Only 1.8 million species identified ◦ Little known about nature and ecological roles of species identified  Document little changes in DNA  Use species–area relationship  Mathematical models

 We should prevent the premature extinction of wild species because of the economic and ecological services they provide and because they have a right to exist regardless of their usefulness to us.

 Instrumental value ◦ Use value  Ecotourism: wildlife tourism  Genetic information ◦ Nonuse value  Existence value  Aesthetic value  Bequest value  Ecological value

 1989 international treaty against poaching elephants  Poaching on the rise  Track area of poaching through DNA analysis of elephants  Elephants damaging areas of South Africa: Should they be culled?

 Intrinsic value: existence value  Edward O. Wilson: biophilia (inherent kinship with the natural world)  Biophobia – against certain organisms

 Vulnerable to extinction ◦ Slow to reproduce ◦ Human destruction of habitats  Important ecological roles ◦ Feed on crop-damaging nocturnal insects ◦ Pollen-eaters ◦ Fruit-eaters  Unwarranted fears of bats

The greatest threats to any species are (in order) loss or degradation of its habitat, harmful invasive species, human population growth, pollution, climate change, and overexploitation.

 Habitat destruction, degradation, and fragmentation  Invasive (nonnative) species  Population and resource use growth  Pollution  Climate change  Overexploitation

Fig. 9-10, p. 193 NATURAL CAPITAL DEGRADATION Underlying Causes Population growth Rising resource use Undervaluing natural capital Poverty Direct Causes Habitat loss Pollution Commercial hunting and poaching Habitat degradation and fragmentation Climate change Sale of exotic pets and decorative plants Introduction of nonnative species Overfishing Predator and pest control Causes of Depletion and Premature Extinction of Wild Species

 Tropical Biologist Bill Laurance, et al.- edges of forest fragments invaded by vines which take over  How large must a forest fragment be in order to prevent the loss of rare trees? – within 100 meters of the edge of a forest fragment 36% of the biomass of old growth trees is lost within years

 Habitat loss and fragmentation of the birds’ breeding habitats ◦ Forests cleared for farms, lumber plantations, roads, and development  Intentional or accidental introduction of nonnative species ◦ Eat the birds

 Seabirds caught and drown in fishing equipment  Migrating birds fly into power lines, communication towers, and skyscrapers  Other threats ◦ Oil spills ◦ Pesticides ◦ Herbicides ◦ Ingestion of toxic lead shotgun pellets ◦ Climate Change

 Vultures poisoned from diclofenac in cow carcasses  More wild dogs eating the cow carcasses  More rabies spreading to people

 Most species introductions are beneficial ◦ Food ◦ Shelter ◦ Medicine ◦ Aesthetic enjoyment  Nonnative species may have no natural ◦ Predators ◦ Competitors ◦ Parasites ◦ Pathogens

Fig. 9-14a, p. 199 Deliberately Introduced Species Purple loosestrife European starling African honeybee (“Killer bee”) NutriaSalt cedar (Tamarisk) Marine toad (Giant toad) Water hyacinthJapanese beetle Hydrilla European wild boar (Feral pig)

Fig. 9-14b, p. 199

Accidentally Introduced Species Sea lamprey (attached to lake trout) Argentina fire ant Brown tree snake Eurasian ruffe Common pigeon (Rock dove) Formosan termite Zebra mussel Asian long- horned beetle Asian tiger mosquito Gypsy moth larvae

Fig. 9-14, p. 199 Stepped Art Deliberately introduced species Purple loosestrife European starling African honeybee (“Killer bee”) NutriaSalt cedar (Tamarisk) Marine toad (Giant toad) Water hyacinth Japanese beetle Hydrilla European wild boar (Feral pig) Accidentally introduced species Sea lamprey (attached to lake trout) Argentina fire ant Brown tree snake Eurasian ruffe Common pigeon (Rock dove) Formosan termite Zebra mussel Asian long- horned beetle Asian tiger mosquito Gypsy moth larvae

 Imported from Japan in the 1930s  “ The vine that ate the South” – might spread as far as the Great Lakes by 2040 if climate change (global warming) occurs  Could there be benefits of kudzu? – source of food, for making paper

 Argentina fire ant: 1930s ◦ Pesticide spraying in 1950s and 1960s worsened conditions  Burmese python –imported as a pet from Southeast Asia. Dumped in the Everglades. By 2100 in most of southern US

 Prevent them from becoming established  Learn the characteristics of the species  Set up research programs  Try to find natural ways to control them

 Population growth  Overconsumption  Pollution  Climate change

 Pesticides ◦ DDT: Banned in the U.S. in 1972  Bioaccumulation  Biomagnification

 Honeybees responsible for 80% of insect- pollinated plants; 110 commercially grown crops; 1/3 US fruit and vegetable crops  30% drop in population  Dying due to? ◦ Pesticides ◦ Parasites ◦ Bee colony collapse syndrome

 Environmental impact on polar bears ◦ Less summer sea ice ◦ PCBs and DDT  2007: Threatened species list

 Poaching and smuggling of animals and plants ◦ Animal parts ◦ Pets ◦ Plants for landscaping and enjoyment  Prevention: research and education

 Indigenous people sustained by bush meat  More hunters leading to local extinction of some wild animals

 We can use existing environmental laws and treaties and work to enact new laws designed to prevent species extinction and protect overall biodiversity.  We can help to prevent species extinction by creating and maintaining wildlife refuges, gene banks, botanical gardens, zoos, and aquariums.  According to the precautionary principle, we should take measures to prevent or reduce harm to the environment and to human health, even if some of the cause-and-effect relationships have not been fully established, scientifically

 1975: Convention on International Trade in Endangered Species (CITES) ◦ Signed by 172 countries  Convention on Biological Diversity (BCD) ◦ Focuses on ecosystems ◦ Ratified by 190 countries (not the U.S.)

 Endangered Species Act (ESA): 1973 and later amended in 1982, 1983, and 1985  Identify and protect endangered species in the U.S. and abroad  Hot Spots  Habitat Conservation Plan (HCP) colony

 Mixed reviews of the ESA ◦ Weaken it ◦ Repeal it ◦ Modify it ◦ Strengthen it ◦ Simplify it ◦ Streamline it

 Species listed only when serious danger of extinction  Takes decades for most species to become endangered or extinct  More than half of the species listed are stable or improving  Budget has been small

 Suggested changes to ESA ◦ Increase the budget ◦ Develop recovery plans more quickly ◦ Establish a core of the endangered organism’s survival habitat

 1903: Theodore Roosevelt- Pelican Island, Florida – brown pelican  Wildlife refuges -547 ◦ Most are wetland sanctuaries- trumpeter swan ◦ More needed for endangered plants ◦ Could abandoned military lands be used for wildlife habitats?

 Gene or seed banks ◦ Preserve genetic material of endangered plants by storing their seeds in refrigerated, low humidity environments  Botanical gardens and arboreta ◦ Living plants- 1/3 rd of the world’s species  Farms to raise organisms for commercial sale

 Techniques for preserving endangered terrestrial species ◦ Egg pulling ◦ Captive breeding ◦ Artificial insemination ◦ Embryo transfer ◦ Use of incubators ◦ Cross-fostering

 Largest North American bird  Nearly extinct ◦ Birds captured and breed in captivity  By 2007, 135 released into the wild ◦ Threatened by lead poisoning

 Species: primary components of biodiversity  Preservation of species  Preservation of ecosystems