Saturday, October 27, 2007

Planet in Peril

I was surprised last night by the quality of CNN's special Planet in Peril. The segment I watched focused on species loss. It went beyond the usual statement that we're losing species at an alarming rate and explained why it matters. Using wolves in Yellowstone as an example, the narrative and excellent photography showed the effects of the absence of wolves in that ecosystem, the resulting overpopulation of elk, the effect of the elk overgrazing, the loss of habitat for birds and small mammals at so on. Wolves have been successfully reintroduced into Yellowstone park and there is strong evidence of the area's return to balance.

I'm looking forward to seeing the three issues Planet in Peril addresses in addition to species loss: global warming, deforestation and overpopulation. Species loss is deeply affected by global warming and deforestation, both of which are affected by overpopulation. We've seen what happens to other species when overpopulation peaks. The death rate in the overpopulated species rises as a result of food shortage and disease (or increased predator population.) Usually the population declines until balance is restored. But sometimes, the habitat is so damaged by the overpopulation that the species does not recover in that area. Which scenario do we think will apply to human overpopulation? Are we prepared to deal with either one?

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