The demography of the lizard, Uta stansburiana Baird and Girard, in southern Nevada

Between 1966 and 1967 populations of Uta stansburiana in southern Nevada increased about 40%. Over the next year they declined by about 50%. These changes are explained in terms of annual differences in fecundity and survival. Most females laid five clutches of eggs in 1966, but only two or three clutches in 1967. Adult survival between 1966 and 1967 was better than during the following year. The capacity for increase, rc, was estimated as 0.0327/month, and cohort generation time, Tc, as 15.32 months from the 1966-67 data. Data from other natural populations of lizards are reviewed and the inferred net reproductive rates (Ro) compared with the history of the populations. Problems in the study of lizard populations are discussed, particularly the difficulty in assessing egg production by species laying several clutches of eggs each season.