I. The problems
A. Human population is nearing 6 billion, and still growing exponentially
1. Human populations are growing in tropical regions and shrinking in industrialized regions
2. This is creating pressure to remove forests for income and farm land
B. Reversible effects on the physical environment
1. Pollution
2. Loss of ozone
3. Global warming due to CO2 release from fossil fuel burning and deforestation
4. Land degradation
C. Irreversible effects: biodiversity loss due to extinctions of species
1. Rainforests are being destroyed at 1.8%/yr.
2. According to the species-area equation (S = CAz), current rate of tropical deforestation will extinguish 0.5% of forest species/yr. At this rate, by 2022, half of the forest species will be gone.
3. Wilson estimates 27,000 spp disappear/yr, 3/h
4. Humans have increased extinction rates by a factor of 1,000 - 10,000
II. Possible solutions
A. Protect habitats in nature reserves
1. Ok for developed nations
2. Difficult in less-developed nations for economic reasons
B. Find ways to benefit directly from saving wildlands (create biological wealth)
1. Chemical prospecting
a. 40% of pharmaceutical are natural (25% are from plants)
b. Only 3% of world's plants have been assayed for alkaloids
c. Chinese use 6,000 of 30,000 plants for traditional medicinal purposes, but few have been studied or used by westerners
d. Anti-coagulants from leeches and vampire bats help with heart disease
e. Wilson argues that this depends on biological inventories. Who will do this?
2. Increase food plant diversity
a. Current food traditions derive from few cultural sources
i. cereal crops
ii. domesticated animals
b. Utilize more ecologically sustainable industries
i. iguanas in forested regions
ii. turtles in Amazon basin
iii. aquaculture
iv. Babirusa pigs, which ingest cellulose, in forested regions
c. Protecting habitat can save novel genetic varieties that can be used to increase yield or disease resistance
Only 1 of 6,273 types of rice tested showed resistance to grassy-stunt virus
C. Change rates of habitat destruction
1. Promote alternative land-use strategies to clear-cutting
a. extractive reserves - e.g. rubber
b. eco-tourism
Tourism to nature reserves now is the number one income producer for Costa Rica, which has the most extensive park system in Central America.
c. strip-logging
2. Promote restoration efforts
3. Promote reintroduction efforts?
a. Zoos currently can breed 900 species
b. Relatively few reintroductions have been successful
i. black-footed ferret
ii. peregrine falcon
iii. golden lion tamarin
c. Reintroductions are very expensive. Not practical for most species
d. Seed banks, however, can retain more and are cost efficient
D. Population control
1. Do we need it?
2. What ethical considerations are involved?