OUT OF EDEN

A silkily written excursion into the evolution of ecosystems and the possible threats to biodiversity from newcomers.

What are the implications—biological, economical, psychological—when new plant and animal types start to bully established indigenous species out of existence? Plant and animal species, as we know, have been roaming the globe from the start. Consider “the burr stowed in the down of a roving bird,” suggests Discover magazine editor Burdick, or the spider billowing for miles and miles on its strand. Species have been colonizing and re-colonizing forever, taking part in the Darwinian struggle, finding niches, being ousted. But what are we to think when a species simply begins to take over, reducing the biodiversity by half, homogenizing the bio-scape, reducing the crop to rot? This is not simply a case of human aesthetics or economic concerns, like, say, a distaste for a swarm of spiders crawling up your pants or the sound or feral pigs crunching on Norway rats. No, these are questions of extinction: of “eco-imperialism” when conservation agencies seek to eradicate culturally significant populations; of the geography of pandemics; of the interplay of disease, host and vector; of what happens when introduced species encourage native species to go hog wild; of the very notion of what constitutes a weed. Invasion biology (studying how ecosystems work by watching them fall apart) is in its infancy, but to Burdick it’s fairly clear that biodiversity is crucial in the thwarting of species homogenization: the more there are, the more resistant the system is to a species’ invasion. Even if ecological communities were coincidences to start with, they become all the more vulnerable to wasteland when reduced to just a few species. In addition to his philosophical-scientific probings, Burdick provides elegant travel narratives to Guam and Hawaii.

An open and broad survey successfully designed to make readers think hard about the Möbius strip of exotic and native, and of the human agency in extinction. (6 illustrations, not seen)