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Chapter 12: Sustaining biodiversity (species/extinction)

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1 Chapter 12: Sustaining biodiversity (species/extinction)
Land and Water Use Unit

2 Types of Extinction Local extinction: better known as extirpation. A species is no longer found in an area it used to inhabit, but can be found elsewhere. Ecological extinction: too few members of that species exist in an area to continue to play their role in the ecology of an area (predator, prey, etc.) Biological extinction: true extinction. No members of that species exist on Earth. Example: dinosaurs, passenger pigeon

3 Remember these? Background extinction: “Normal” extinction that occurs at a low rate: 1-5 species per million. May be due to evolution… Mass extinction: Extremely high rates of extinction. There have been 5 mass extinctions and we may be in a possible 6th mass extinction. Reread 6th extinction from Ch. 1 internet activity for homework.

4 Who’re you calling threatened?
Endangered species: Numbers are so low that the species could soon become extinct. Protected by law. (Endangered Species Act of 1973) Threatened species: Numbers are low enough that species could soon become threatened. Protected by law. Special concern: Animals that are suspected to be experiencing problems, but no documentation has been made. Not protected by law.

5 Fixed migratory patterns Commercially valuable
Characteristic Examples What puts them at risk? Low reproductive rate (K-strategist) Blue whale, giant panda, rhinoceros Specialized niche Blue whale, giant panda, Everglades kite Narrow distribution Many island species, elephant seal, desert pupfish Bengal tiger, bald eagle, grizzly bear Feeds at high trophic level Fixed migratory patterns Blue whale, whooping crane, sea turtles Rare Many island species, African violet, some orchids Commercially valuable Snow leopard, tiger, elephant, rhinoceros, rare plants and birds Large territories California condor, grizzly bear, Florida panther

6 Percentage of threatened/ endangered
34% (51% of freshwater species) Fish 24% Mammals 20% Reptiles Percentage of threatened/ endangered 14% Plants Birds 12%

7 Indian Tiger Range 100 years ago Range today (about 2,300 left)

8 Black Rhino Range in 1700 Range today (about 2,400 left) Black Rhino

9 African Elephant Probable range 1600 Range today (300,000 left)

10 Asian or Indian Elephant
Figure 12-7d Page 232 Asian Elephant Former range Range today (34,000–54,000 left) Asian or Indian Elephant

11 Maintenance through Conservation
Maintaining and protecting wildlife consists of 3 major approaches: Species approach – protecting endangered species though legislation. Ecosystem approach – persevering balanced ecosystems

12 Maintenance through Conservation
3. Wildlife management approach – managing game species for sustained yield through interaction treaties to protect migration species, improving wild life habitats, regulating hunting and fishing, creating harvest quotas and developing population management plans.

13 Why should we care??? Instrumental value
Gene pool/genetic information (useful for vaccines, resistance) Wildlife tourism (existential value) Recreational pleasure Place in ecosystem (pollinator, keystone, indicator, etc) “It’s like burning books before you read them.”

14 Causes of endangerment
Habitat destruction (for resources, farmland, residential, pollution) Introduction of alien/non-native/invasive species Overexploitation (over-harvested, over-hunted, poaching) Disease Pollution Interrupted migration

15 Oops – I did it again Introduced on purpose:
Kudzu vine (prevent erosion ) House sparrow (eat cankerworms -1950) Carp (“world’s finest fish” ) Nutria (fur) Ring-neck pheasant (hunting -1881)

16 Figure Page 236

17 Kudzu spreading

18 Deliberately introduced Species
Figure 12-9a Page 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

19 Unintentional introduction
On ships, boats On people On shipping crates On tire treads Examples: Fire ants Zebra mussel Water millfoil

20 Accidentally introduced Species
Figure 12-9b Page 235 Sea lamprey (attached to lake trout) Argentina fire ant Brown tree snake Eurasian muffle Common pigeon (Rock dove) Formosan termite Zebra mussel Asian long-horned beetle Asian tiger mosquito Gypsy moth larvae Accidentally introduced Species

21 Argentina Fire Ant Distribution
1918 2000 Argentina Fire Ant Distribution

22 Ecosystems Vulnerable
Characteristics of Successful Invader Species Characteristics of Ecosystems Vulnerable to 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 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 Will we be invaded?

23 It’s the law… CITES: Convention on International Trade in Endangered Species: 1975, treaty signed by 160 countries, lists 900 species that cannot be traded either alive or as products. CBD: Convention on Biological Diversity. Signed by 186 countries legally binds governments of signing countries to attempt to reverse the loss of biological diversity. Each country forms a national conservation plan. Lacey Act of 1900: US act, can’t transport live or dead wild animals or parts of them across state borders without permits Endangered Species Act: Amended in 1982, 85, 88. Identifies animals as threatened or endangered and protects them by law.

24 Zoos or Not? Read pages Utilize the internet for additional support for your essay. Essay – should be 3-4 paragraphs on whether or not zoos/aquariums/captivity programs should be utilized for endangered/threatened species (with no intention of releasing to the wild)

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