Linking species distributions and thermal physiology to understand climate change impacts on ants

Climate change is impacting the abundance and distribution of organisms globally. Ant species critical thermal limits (CTLs; the temperatures at which locomotion is lost) can influence their distributions. However, CTLs in ant species can differ across latitudes and seasons because organisms experience different temperatures across space and time. Since slope aspects experience differing levels of temperature variation this may be reflected in the thermal traits of the ant community. Changes in temperature regimes as a result of climate change, may be altering community thermal traits as well. Specifically, we asked; 1) do CTLs differ between aspects, and 2) is the ant community thermal index increasing? We tested the CTLs for ant assemblages based upon slope aspect using a dynamic ramping protocol. Additionally, we combined contemporary and historical data to see if there has been a shift towards more heat-tolerant species. CTLs will likely constrain the aspect(s) that species reside in. Due to increases in species who forage at a wider range of temperatures and increases in local temperatures, we expect that the community thermal index will increase. Testing CTLs at a small scale to look at variation based upon topography will allow us to make better predictions about species distributions and how they may be constrained under altered temperature regimes. Additionally, by measuring shifts in the community thermal index and temperature niches for species, we can determine if certain areas are at a higher risk of species extirpation.