Meeting Abstract
Thermal tolerance plays a major role in determining species distributions across space and time. By defining the range of temperatures in which a species can survive and reproduce, thermal limits constrain the location and range of suitable habitats. For ectotherms, thermal tolerance breadth increases with latitude, which is driven by a decrease in lower thermal limits at higher latitudes. Upper thermal limits are generally conserved across species, suggesting that ectotherms have a limited potential to adapt to the rapid increase in temperature predicted with anthropogenic climate change. However, populations within a species, especially widespread species, may exhibit variation in thermal limits. Such variation plays a critical role in predicting the resilience of species to climate change. Here, we measure critical thermal minimum and maximum in a lungless salamander species, Plethodon cinereus, from North Carolina to Maine to determine whether thermal limits and thermal tolerance breadths vary among populations in relation to environmental temperature. Plethodon cinereus is the most widely distributed Plethodon species in the eastern US, extending farther north than any other lungless salamander. Given that lungless salamanders are dispersal-limited and physiologically sensitive to temperature, we predict that thermal limits will reflect the environments in which they live. Further, we predict that Plethodon cinereus has been able to exploit such a large geographic range through local adaptation of thermal limits. By measuring the environmental drivers of thermal limits in a widespread species, this study will contribute to our understanding of species’ distributions and potential responses to climate change.
