Meeting Abstract
Climate change might dramatically increase extinction risk by threatening the most basic, physiological requirements for survival. Despite the threat of overheating and dehydration, very few studies have demonstrated a physiological basis for population-level responses to climate change, especially in endotherms. Climate change has the potential to challenge endotherms by disrupting their ability to maintain a stable body temperature, a fundamental requirement for survival. We evaluated community responses to climate change in the Mojave Desert over the last century using occupancy surveys for birds and mammals. As part of the Grinnell Resurvey Project, we compared the change in occupancy from modern surveys with surveys originally conducted by Joseph Grinnell et al. in the early 20th century. We then explored the physiological basis of species’ responses to climate change using heat flux models that estimated the climate-driven change in thermoregulatory requirements for birds and mammals. For bird communities, we found a nearly 50% reduction in biodiversity across our resurvey sites. Mammal communities however were relatively stable over the same time period. Avian declines were largely explained by the increase in thermoregulatory cooling costs over the last century, whereas mammal communities were not affected by thermoregulatory costs. Moreover, heating costs from climate change declined more in mammals compared to birds, and most mammals did not experience an increase in cooling costs. Our study demonstrates that birds and mammals have markedly different thermoregulatory experiences of climate change that influence population-level responses to recent climate change.
