Transcription

1 Endangered Species Act of 1973 requires the United States Department of the Interior to identify and protect species that are in danger of extinction endangered species: species whose chances of survival and reproduction are in immediate jeopardy a threatened species is one that is likely to become endangered endangered species are protected by this law, and may not be killed or harmed, including the destruction of their habitat The US Fish and Wildlife Service protects endangered species, species currently listed as endangered Brewer 1

2 Extinction With or Without Humans Extinction of species has occurred throughout Earth's history the extinction of the dinosaurs circa 65 mya 2/3 of all species on the planet became extinct Brewer 2

3 Environmental Science Extinction With or Without Humans Extinction of species is a natural process animals better suited to environmental changes are more likely to survive Human activities increase the rate of extinction human population growth decreases available space for other species to exist Brewer 3

4 Extinction With or Without Humans Poaching: illegal hunting of endangered species Ex. poachers hunt and kill tigers for traditional Chinese medicines Habitat fragmentation: break up of habitat leads to isolated, small populations. Limited breeding leads to mutations and birth defects. Brewer 4

5 A Little Fish vs. A Big Dam In 1967 construction began on the Tellico Dam in Tennessee Brewer 5

6 A Little Fish vs. A Big Dam Construction of the dam would change the stream into a lake, destroying the habitat of the snail darter fish Brewer 6

7 A Little Fish vs. A Big Dam According to the Endangered Species act, the dam could not be built, thus construction was halted In 1978, the Supreme Court ruled that the Endangered Species Act, but Congress passed a law allowing a panel to exempt projects from the act. The population of snail darters was transplanted to other locations to ensure the survival of the species. Additional populations of snail darters in other streams led to reclassification of the species from endangered to threatened Brewer 7

8 Will the Warblers Be Next? Kirtland's Warbler is a small bird threatened by habitat loss migration pattern from the Bahamas in winter to a few counties in N. Michigan 90% of the population breeds in the watershed of a single stream builds its nest in the sandy soil under Jack pines Brewer 8

9 Will the Warblers Be Next? The cones of jack pines only open when exposed to fire Early settlers controlled forest fires, thus reducing the number of new jack pines that grew Now jack pines are managed by logging companies to provide a continuous supply of trees for warblers and people Brewer 9

10 Will the Warblers Be Next? Warblers are also threatened by cowbirds Cowbirds lay their eggs in the nests of other birds, leaving the host species to raise their young cowbird chicks grow more quickly than warbler chicks and eventually push the warbler chicks out of the nest Brewer 10

11 The California Condor largest bird in North America numbers declined sharply after 1900, with only 60 members counted in 1972 Brewer 11

12 The California Condor DDT: pesticide widely used and linked to thinning of egg shells of large birds thin eggs tend to break poisoning of coyote and other animals led to poisoning of condor through bird's scavenging behaviors With active breeding programs, condor numbers have increased to approximately 120 individuals Brewer 12

13 Environmental Science Back from the Brink when settlers arrived, millions of bison were killed on the Great Plains a population of 60 million reduced to 1000 by Today there are approximately 200,000 bison, mostly in private herds The largest public herd is found in Yellowstone National Park, with 25,000 individuals Brewer 13

14 Return of the Wolves After massive over hunting of natural prey such as buffalo, deer, elk, etc... wolves turned to livestock Ranchers poisoned wolves with bait and managed to kill over 100,000 from 1883 to 1942 Brewer 14

15 Return of the Wolves The Endangered Species Act requires that the U.S. Fish and Wildlife Service develop recovery plans for endangered species Breeding packs were introduced from Canada into central Idaho and Yellowstone Park. These packs have increased in numbers. U.S. Fish and Wildlife proposed classifying wolves from the Great Lakes to threatened status. States must have protection plans in place before a species can be removed from the endangered species list Brewer 15

16 Why Not Let Them Die? potential medicines and chemicals that may be extracted from plants 1/4 of all drugs come from plants The genes of wild species can improve the yield and longevity of the species we use a food sources (wheat, corn, soybeans, etc..) Species may have future uses that we would lose if they were to become extinct biodiversity: number of species in an ecosystem; the more species exist, the more stable the ecosystem keystone species: species essential to keeping an ecosystem in balance a loss of which would cause a chain reaction in losses of many other species Brewer 16

17 The Future of the Endangered Species Act Critics consider it a barrier to economic growth Incidental take permits allow landowners to carry out activities that may harm endangered species Habitat Conservation Plan: plan of action during an incidental take permit where specific steps are outlined to lessen the impact of the harmful activities. Ex. development of Las Vegas Valley halted due to desert tortoise. Land was bought to relocate tortoise to new habitat High profile species (Bald Eagle, California Condor) often get more resources than lesser known endangered species. Endangered species continue to be identified. Brewer 17

18 Brewer 18

19 Attachments