Thermal Stress - It affects all

As global temperatures rise, they impact both plants and animals, negatively. The increase in temperature has direct ambient impacts on animals' thermoregulation. The increase in temperature also has an affect on the performance of grasses. These effects are shown in the figure to the right. In all, each of these mechanisms will cause body sizes of bison to decrease. We are trying to figure out which one is the primary driver of body size. 

Thermal Imaging

Thermal image of a mature female bison facing into the sun with wind at her back. Notice the white, yellow, and red areas are warm, whereas the greenish-blue and blue areas are cool. J.M.Martin, 2017.

To measure the ambient temperatures affecting bison thermoregulation from heat loads, I will be using a thermal camera to photograph and video bison in about 15 locations from Saskatchewan to Texas in the Great Plains. The north to south difference in these locations have a large body size variation and a large difference in annual and seasonal climates. Our hope is to see the two extremes, winter and summer, and measure how bison handle heat loads through heat dissipation and heat retention. This will give us an idea of thermoregulatory (energetic) costs to metabolism. If more energy is spent on heat dissipation, they will likely consume less food and not be as efficient with the food they ingest. 

I ask to visit your ranch to thermally image your bison two times; once in the peak of summer (July-August, 2017) and once again in the depth of winter (January-February, 2018). I am most interested in locations in the Great Plains due to limited time and funding.