COLONIZATION AND SATURATION OF HABITATS BY LIZARDS

We studied the colonization of habitats by four species of iguanid liz ard (Urosaurus oi natus, Sceloporus graciosus, S. undulatus, and Uta s tansburiana) to determine differences among the species in colonizatio n, differences among habitat types in colonization, and the lime traje ctory of colonization. We surveyed lizards on eight study plots in thr ee habitats after a density reduction experiment. We discovered no dif ference among lizard species in their recovery relative to numbers rem oved. However, there were significant differences in recovery among ha bitats, suggesting an important role of habitat type in the resilience of the lizards to the perturbation. Colonization by lizards was rapid and most study plots were colonized within 2 to 3 mo of the manipulat ion. One year after the experiment, all species were represented on ai l plots. Saturation (ratio of marked lizards to the number removed on each plot) was significantly different between the first and all other post-manipulation census periods. There was no significant difference in saturation among the second (1 yr), third (15 mo) and fourth (27 m o) census periods, suggesting asymptotic saturation within 1 yr of the perturbation. The pattern of colonization by resident lizards was sim ilar to that of all lizards (residents and transients). There was no d ifference in saturation among species, but there were significant habi tat and census period differences in saturation.