We tend to think of vegetation in the Southwest as occurring in layers by elevation. Desert holds its grip at the lowest altitudes, and then one passes progressively upwards through desert grassland, pinyon-juniper woodland, ponderosa pine forest, and into spruce-fir or mixed coniferous forest in the high mountains. In general, that is what we see, but sometimes things aren't quite that neat.
Drive northward of the city of Truth or Consequences, and suddenly
junipers nestle amongst Chihuahuan Desert plants. Or climb into the Sacramento
Mountains toward Cloudcroft, and there's a spot or two where individual plants of
creosotebush, pinyon, and juniper stand within spitting distance of each other. In
other places, such as the rolling countryside west of Carlsbad, a broad ecotone between
desert and woodland communities thoroughly mixes the two. In any patch of land,
climatic conditions vary according to a variety of local factors. Especially where
different plant communities approach one another, a mosaic of microclimates spreads
across the land, and the happy coincident of a climatic condition and a seed provides a
home amongst aliens.
Listen to the Audio (mp3 format) as recorded by KTEP, 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.