Meeting Abstract
Winter rainfall has been implicated as a major determinant of desert lizard reproduction. Ongoing drought in the western United States provides an opportunity to observe the effects of rainfall on lizards. I used multi-year data from several populations of side-blotched lizards, Uta stansburiana, in Nevada to examine the effects of drought on body condition and reproduction. During 2012 drought developed in central Nevada and at one site only 73% of normal winter rains fell from October, 2011, to March, 2012. Drought persisted and intensified in the winter of 2012-13 when only 44% of normal rains fell. Drought corresponded to a marked reduction in lizard body condition (scaled mass index [Peig & Green, 2009]) such that lizards in 2013 were ~10% lighter than pre-drought lizards. In 2013 the condition of males (10% reduction from pre-drought levels) appeared worse than females (7% reduction). Drought eased somewhat in the winter of 2013-14 and rainfall was 84% of normal. In 2014 lizard body condition improved, but was still ~8% below pre-drought levels. Interestingly, in 2014 the condition of females (11% reduction from pre-drought) appeared worse than males (6% reduction). Drought also affected reproduction. In April, 2013, 36% of females were gravid, but by June only 4% were gravid. By way of comparison, females from nearby sites outside the area affected by exceptional drought reproduced both early (in April 32% were gravid) and late (in June 33% were gravid) in the breeding season. The easing of drought allowed females at the affected site to breed late as well (in June, 2014, 17% were gravid). This late-season reproduction may actually explain the reduced condition of females in 2014. Thus, winter rainfall and drought appear to create an interaction between body condition and reproduction in side-blotched lizards.
