Meeting Abstract
Changing environmental conditions, such as drought, can impose life-history trade-offs on animal populations. Over the past several years, drought conditions have influenced the life history of side-blotched lizards (Uta stansburiana) in northern Nevada. Ongoing monitoring of lizard populations has revealed that the effects of and recovery from the worst of the drought, which occurred in 2013, may have involved multiple life-history trade-offs. Drought conditions caused a decline in body condition of all lizards, especially females, accompanied by the absence of late-season of egg laying (evidence of a shift from reproduction to survival). This resulted in a marked alteration to the body size distribution of adults. By 2014 when the drought had eased, all lizards were two years old or older. Hence, mean adult body size in 2014 was 7-10% greater than during the drought (~3 mm longer; ~0.7 g heavier) and standard deviation in body size was low. However, the older females, which had dominated the adult breeding population in 2014, were largely absent from the population in 2015, two-years post-drought. I infer from these observations that females first shifted their life history tactics from reproduction (in 2012) to survival (in 2013) then back to reproduction (in 2014). Moreover, because there were relatively few three-year old females in 2015, reproduction by females in 2014 appears to have been at the expense of continued survival by those females. In contrast, the two-year old (and older) males survived the 2013 drought and were able to enter the largest sizes classes post-drought in 2014 and 2015.
