Meeting Abstract

72.3  Sunday, Jan. 6  Climate-change trade-offs: benefits from longer growing seasons may be cancelled out by the costs of milder winters ZANI, P.A.; Lafayette College zanip@lafayette.edu

An expanding body of literature has demonstrated that global climate change continues to impact adversely many populations, species, and ecosystems. However, life-history theory also predicts possible benefits from longer growing seasons and less severe winters, particularly in ectotherms. To test the idea that climate change will have benefits as well as costs, I studied the impacts of growing-season length on growth and overwintering conditions on survival using side-blotched lizards (Uta stansburiana). Experiments in replicate field enclosures revealed that growing-season length has a direct effect on overwintering size. Laboratory experiments revealed that both size and overwintering temperature have direct effects on winter survival. Larger lizards are more likely to survive regardless of the temperature, a result confirmed in nature. Furthermore, animals in colder winter microenvironments are more likely to survive than those in slightly warmer winter environments. These results indicate that milder winters caused by global climate change have the potential to impact negatively ectotherm populations. Yet, longer growing seasons may offset these losses by allowing for additional growth. Thus, the environmental alterations associated with climate change may be both beneficial and detrimental and the long-term persistence of certain organisms may depend on the relative strength of their effects.