Meeting Abstract
Climate change is occurring worldwide, but the impacts of change are not predicted to be equal among organisms. For example, mountaintop endemics are expected to be particularly susceptible to warming because they are thought to be adapted to relatively cool conditions and, as conditions warm, will have nowhere to flee. Many of these predictions are based on correlative modeling approaches, which assume or treat species as physiologically adapted to their local conditions. Mechanistic niche models, in contrast, incorporate data of species’ behavior and physiology to predict when a species can be active. Here we demonstrate that behavioral thermoregulation can buck expected trends in species distributions under climate change. We present the results of correlative and mechanistic niche models for three species of Anolis lizards from the island of Hispaniola, one widespread species A. cybotes, and two mountaintop endemics, A. armouri and A. shrevei. Correlative models predict a significant decrease in range size of both mountaintop endemics to near extinction levels, with the range size of the widespread species staying constant under climate change. In contrast, mechanistic niche models predict increased activity for mountain endemics, including beyond their current ranges. The mechanistic model also predicts increased activity for the widespread species, A. cybotes, within the range of the mountaintop endemics. Our results suggest that climate change will increase the thermal suitability of their current ranges, both for montane endemics and their lowland competitor. As such, montane endemics may be at risk of extinction, but not as a direct result of temperature changes, but rather through the indirect effects of biotic interactions.
