In these days of urban life, we too often are unaware of natural changes taking place in our region. Indeed, we often assume that there are no changes, except perhaps those directly attributable to human influences. Fortunately for people who like to live in a dynamic system, natural change is the norm rather than the unusual. One of the more apparent processes of change is in evolving geographic ranges of organisms.
In our Southwestern deserts, changes in the distribution of mammals is
apparent within historic times. Javelina have moved north and west from their range
southeast of El Paso to the vicinity of Alamogordo. Coatis apparently have been spotted
as far north as Truth or Consequences, far from their early distribution in the
southwestern corner of New Mexico and southern Arizona. And the Tawny-bellied Cotton
Rat has descended into the Rio Grande Valley in the middle stretches of that river in
New Mexico, displacing the Hispid Cotton Rat. Depending on your personality, it's
either comforting or disturbing that change is as omnipresent in nature as in human
affairs.
Listen to the Audio (mp3 format) as recorded by KTEP, National Public Radio for the Southwest.
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.