Song of the Dodo: Island Biogeography in a Time of Extinction

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Song of the Dodo: Island Biogeography in a Time of Extinction

by Ed Alkaslassy <alkaslae@pacificu.edu>


Song of the Dodo: Island Biogeography in a Time of Extinction. 1996. David Quammen.


Humans have caused and are causing the permanent extinction of many unique living beings such as the Dodo (a pigeon-like bird). A disproportionate number of those extinctions have taken place on islands. Why are island-dwelling organisms so vulnerable to extinction? Because island populations are relatively small they have little genetic variation for coping with change and are more likely to suffer "random" declines after unexpected catastrophes. And while they are isolated from the fresh genetic variation of mainland populations that isolation has not protected them from a host of harmful human activities.

Lessons learned from islands can now be applied to mainland species. The sobering truth is that humanity is turning the entire surface of the earth into isolated fragments of land that are effectively islands on which species become marooned and are at greater risk of extinction. Shopping malls, highways, and agricultural fields can all be impassable barriers ("oceans") for species. Even protected "islands" of land cannot preserve their native species: surveys of several National Parks in the western U.S. show that they have lost 40% of their large mammal species since being created less than one hundred years ago.

We cannot know the song of the Dodo now that we have extinguished it. How much more of our biological world will be unknown to future generations? The mission of the new discipline of conservation biology is to develop strategies for retaining viable populations and functioning ecosystems over the long term, given that the world is now "in pieces".