1. Global Change and a Sustainable Future
Chapter 18

2. Mass Extinction Biodiversity a. instrumental and intrinsic value
Extinctions
a. “last member of the species dies”
b. 5 major
- 50,000 species extinctions/yr (0.5%)
c. now experiencing the 6th
- human cause
Instrumental – food, medicine, building materials, regulating services (plants removing CO2)
Intrinsic – no direct benefit to people but they are valuable to us and we need to preserve them

3. Global Declines in Genetic Diversity
Wild Organisms
a. prone to inbreeding depression
- produces impaired offspring
b. natural causes v. human causes
Natural causes – bottleneck effect
Human causes – eradication of predators

4. Crops and Livestock
a. producers have started concentrating on
breeds that are most productive resulting
in lower genetic variation
b. forces breeds to become endangered

5. Global Decline in Species Diversity
Status of species
a. Data deficient – no reliable data to assess
b. extinct – no longer exist since 1500
c. threatened – high risk of extinction
d. near-threatened – very likely to become
threatened
e. least concern – very widespread species

6. Since 1500
a. birds
- 10,000 existed, 133 extinct, 21% threatened
b. mammals
- 5,500 existed, 79 extinct, 25% threatened
c. amphibians
- 6,200 existed, 39 extinct, 49% threatened

7. Causes of Declining Biodiversity
Habitat Loss
a. greatest cause of decline
ex) northern spotted owl
- old growth forests
The old trees have been removed for lumber and housing developments and it has completely transformed the old tree forest into a different habitat and it has reduced the number of spotted owls.

8. a. native species – native to the land b. alien/exotic species
Alien Species
a. native species – native to the land
b. alien/exotic species
- species living outside of their normal range
- introduced accidentally or intentionally
c. invasive species
- no natural enemies
- 2 most common in North America
* Kudzu vine
* Zebra Mussel
- act as predators,
pathogens, competitors
to native species
Accidentally – rats that stow away in packaging containers, pests that are on packaging containers
Intentional – exotic plants being sold in greenhouses or for outdoor landscape
Some alien species are not a threat and have no negative effect, but if they spread rapidly, they are known as invasive species
Kudzu
- native to Japan and Southeast China and was introduced to the United States in 1876
- we were encouraged to plant kudzu to help reduce erosion in our fields
- herbivores did not eat the kudzu so it spread very rapidly and taking over most flowers and creating too much shade for the trees
Zebra Mussel
- native to the Black Sea and Caspian Sea in Asia
- large cargo ships that traveled in these seas unloaded their cargo in Asian ports and then pumped water into their storage tanks to make sure the ship
would sit low enough to remain stable
- but they started just loading on new cargo and no longer needed the water to put on the boat so they pumped it back into local waters resulting in a increase of zebra mussels
- positive
* remove large amounts of algae and contaminants
- negative
* physically crowd out many native mussel species and may consume too much algae

9. Overharvesting
a. removed faster than population can replace
themselves – can cause extinction
b. Dodo bird, sloths, mammoths
c. poaching
d. regulations
- state and federal restrict hunting/fishing of
game animals to particular times of the year
and limit the number that can be harvested

10. Pollution
a. pesticides, heavy metals, oil spills,
endocrine disruptors (reproduction),
release of nutrients (N and P), thermal
pollution (cooling of power plants)
Climate Change
a. changes in patterns of temperature and
precipitation in different regions of the
world and how it will affect the organisms

11. Conserving Biodiversity
Two general approaches
a. single species approach
b. ecosystem approach

12. Single Species Approach
a. focuses on one species at a time
b. approach
1. encourage population rebound
- improving living conditions
- providing additional habitat
- reducing contaminants
- captive breeding (California Condor)

13. c. legislation 1. Marine Mammal Protection Act - prohibits killing of all marine mammals in the US and prohibits the import/export of an marine mammal body parts - exceptions can only be made through: * US Fish and Wildlife Service * National Marine Fisheries

14. 2. Endangered Species Act (1973) - authorizes US Fish and Wildlife service to determine which species can be listed as threatened/endangered - prohibits the harming of the listed species as well as trade of species - authorizes govnt to purchase habitat for species - listed species * 201 invertebrate * 795 plants * 381 vertebrate

15. 3. Convention of Biological Diversity - international treaty - 3 objectives * conserve biodiversity * sustainably use biodiversity * equitably share the benefits that arise from commercial use of genetic resources

16. Ecosystem Approach
a. preserves particular regions (biodiversity
hotspots) – national parks, marine reserves
b. Factors to consider
1. size and shape of protected area
2. connectedness to other protected areas
3. recognize how to incorporate
conservation while seeing the need for
sustainable habitat use for human needs

17. c. Island Biogeography applied to protected areas 1
c. Island Biogeography applied to protected areas 1. distance between areas - further apart, harder for species to travel among them 2. metapopulations 3. edge habitat - where two different communities come together
Metapopulations – collection of smaller populations connected by occassional dispersal of individuasl along habitat corridors