Biodiversity 2

Biodiversity is intimately linked with ecosystem function and services

there have been five great extinctions; we may be in the midst of the sixth

-Phase 1: began 100,000 years ago with the spread of humans
-Phase 2: began 10,000 years ago with the dawn of agriculture
-Phase 3: began 250 years ago with scientific and industrial revolutions

-extinctions usually evolve into something else
-large animals most at risk

-great migrations: migration of one prepares habitat for the next

Threats to Biodiversity:
1. over-exploitation
2. exotic species
3. habitat destruction
4. climate change
5. pollution
6: domino effects

Nature reserve habitats change over time: must manage the matrix
-size matters

-background extinction: rate in historical records
-mass extinctions occur episodically
-anthropogenic extinctions: human-caused

Probable rate of extinction:
-estimate number of species
-estimate rates of habitat loss
-use species-area relationship to estimate loss

estimated loss of 25-50% of world's species by 2100

-habitat loss biggest problem
-then invasives
-then hunting

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