SEASONAL OCCURRENCE AND HABITAT UTILIZATION BY LIZARDS IN SOUTHWESTERN NEW-MEXICO

Herein we describe how members of a lizard community in southwestern New Mexico vary in their seasonal occurrence and utilization of habitat. Except for January 1984, one or more of the following 11 species of lizards were active during each of the 24 months of study (April 1983 through March 1985): greater earless (Cophosaurus texanus), zebra-tailed (Callisaurus draconoides), leopard (Gambelia wislizenii), desert spiny (Sceloporus magister), eastern fence (Sceloporus undulatus), side-blotched (Uta stansburiana), tree (Urosaurus ornatus), Texas horned (Phrynosoma cornutum), round-tailed horned (Phrynosoma modestum), desert-grassland whiptail (Cnemidophorus uniparens), western whiptail (Cnemidophorus tigris). Desert-scrub vegetation covered about 20% of the study area, with bare ground (i.e., soil, sand, gravel, or rocks) accounting for about 70%, and debris (i.e., sticks, limbs, and leaf litter) the remaining 10%. Lizard species segregated into two major habitat groupings, one composed of sites having relatively abundant cover and vegetation (e.g., sites occupied by S. magister, U. ornatus, U. stansburiana, and C. tigris) and the other characterized by more open sites (e.g., sites occupied by G. wislizenii, C. draconoides, P. modestum, and C.texanus). Species such as C. draconoides and G. wislizenii utilized microhabitats in roughly the same proportions as available. Other species such as S. magister and U. ornatus, the former found in association with nests of white-throated woodrats (Neotoma albigula) and the latter associated with trees or dense debris, were more selective. The present study, which provides useful information for formulating land management decisions, is one of the few to study a lizard community throughout all months of the year.