Ch10, Section 2: Biodiversity at Risk Standards: SEV1a, 1d, 1e

What is the difference between threatened, endangered, & extinct? Threatened- species is declining so much it is likely to become endangered if not protected. Endangered- species that is likely to become extinct if not protected. Extinct- last members of a species die. Local extinction- species is extinct in local area/region Global extinction- species is extinct on entire planet

What are natural causes of extinction? There have been 5 major natural mass extinctions since the beginning of geologic time. These are caused by Asteroids Major volcanic eruptions Both caused drastic changes in climate. Many species could not adapt quickly enough so they died.

What is the “6th extinction”? “6th extinction” is not caused by natural events- caused by humans. Rate of extinction has increased by multiple of 50 since 1800.

What types of species are prone to extinction? Generalist species Large populations & adapt easily NOT likely to become extinct Ex: cockroach, rat, racoon Specialist species Small populations & can’t adapt easily b/c they have specialized needs for food or habitat Includes many species that migrate-whooping crane May be exploited by humans Ex: giant panda, salamanders Whooping crane needs wetlands to stop in during migration to feed. Wetlands along migration routes are being drained and used for residential housing or farming. Bird populations are suffering due to removal of wetlands. Panda only eats bamboo. As population in China rises, more people spread into bamboo forests, destroying food source. Also habitat fragmentation (breaking up habitat by building roads, houses, etc) keeps pandas from finding each other. They are only fertile 3 days a year so if they can’t find each other during that time they will not reproduce that year. Salamanders have specialized needs for water temperature, pH, and oxygenation. Pollution is affecting their habitats.

How do humans cause extinctions? Remember H-I-P-P-O These are the 5 ways humans cause extinctions. H- Habitat Destruction I- Invasive exotic species P- Pollution P- Poaching O- Overharvesting Picture 1- trees being cut down in rainforest to build road. Picture 2- invasive kudzu Picture 3- waste pipe dumping into wetland area Picture 4- poaching of tigers in India for their skins, gall bladders, teeth Picture 5- overharvesting fish with large nets.

H- Habitat Destruction/Fragmentation Humans use land to Build homes Build roads, canals For agriculture Using the land, we destroy & fragment animal habitats Causes 75% of all extinctions Ex: Florida Panther- range consisted of entire southeast, now restricted to southernmost tip of Florida thanks to habitat fragmentation. Need lots of territory to live & hunt

I- Invasive exotic species Endemic- native to an area and usually limited in number Exotic species- not native to a particular area. Invasive- cause damage in a particular area. Invasive exotics are more successful than endemics b/c: Do not have natural predators Outcompete endemic species for space/food Ex: kudzu, fire ants, zebra mussels, snakehead fish Picture 1- Fire ant mounds in field in southeast. Picture 2- crayfish covered in zebra mussels- zebra mussels grow on everything that is either not moving or slow moving. Clog dam pipes- costs $ to clean out. Picture 3- snakehead fish- Maryland DNR is offering $200 gift cards to Bass ProShop for capturing these fish that devour native fish.

Invasive exotics introduced intentionally…? Invasive exotic mongoose was brought to Hawaii to get rid of another invasive species- rats. Rats are active at night. Mongoose was active during the day. Instead of eating rats, mongoose ate native birds & their eggs. Epic Fail.

P- Pollution Types of pollutants Cleaning agents Drugs & other chemicals Burning fossil fuel- makes water acidic for fish & amphibians Pesticides Ex: DDT- used in 1950’s Caused egg shells of bald eagles to become too thin. Mother birds sat on eggs to incubate and they would break. Main reason bald eagles were on endangered species list. DDT banned in 1970s and now bald eagle populations have recovered.

P- Poaching Poaching- illegal hunting of an organism Laws are established in many countries to prevent illegal hunting. In developing countries these organisms may be a source of food, medicine or income. Should they stop killing “pretty animals” or feed their families with them? Ex: all large cats (skin, teeth gallbladders), elephants (ivory tusks), rhinos (horns for “medicine”)

O- Overharvesting In the past, catching fish or whales was done with small boats, harpoons, rods/reels Now technology enables us to locate & harvest them in large quantities. Ex: most commercial fish are overharvested Bottom pic- pilot whales caught in Faroe Islands

What regions have the most critical levels of biodiversity? Tropical rainforest Cover less than 7% of land but have 50% of world’s species Still many unknown species that may benefit man (medicine) Cora reefs & coastal ecosystems Invertebrate “nurseries”- many mollusks & crustaceans lay eggs here & babies grow up here Used for food, ecotourism Protect mainland from waves, storms Not well protected by laws- overfishing & pollution Islands Have distinct & limited number of species Very vulnerable to disturbances by people

What is a biodiversity hotspot? Biodiversity hotspots The most threatened areas of high species diversity. Have high number of endemic species and threatened by human activities Most have lost 70% of their original habitat thanks to human encroachment. Ex: Madagascar (see map)

Are any biodiversity hotspots in U.S.? Yes! Some of our hotspots: FL Everglades Midwestern Prairies CA coastal region Pacific northwest rainforest Hawaii Organisms threatened by Land use for agriculture & housing Dam construction Overuse of water Mining