The biological diversity of an area depends on its history, variety of niches, and isolation of habitats from one another. Perhaps the epitome of isolation in our region is that of the desert spring whose runoff dries out long before encountering another body of water. In past, wetter times, some organisms managed to reach such springs. With the drying of the region into desert, however, many of these were trapped, isolated from others of their kind. Unable to exchange genetic material with others, such populations evolved on their own pathways, eventually becoming different species from their relatives.
One such creature is the Socorro Isopod, an aquatic crustacean looking
somewhat like our familiar pillbug. Isolated in one hot spring complex near Socorro,
New Mexico, the species occurs nowhere else. Between human disturbances and natural
events, the isopod would have become extinct in the late 1990s if a captive population
had not been held elsewhere. Reintroduction has resulted in the current community of
about 2500 individuals, but such vulnerability is one reason we call our desert
fragile.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.