Thermal biology and growth of bison (Bison bison) along the Great Plains: testing four theories of endotherm body size: dataset

This is the supporting dataset for: Martin and Barboza 2020-Thermal biology and growth of bison (Bison bison) along the Great Plains: testing four theories of endotherm body size

Abstract-Body size of bison (Bison bison) declines with rising global
temperature across the fossil record and rising annual temperatures across the
Great Plains, but what are the underlying drivers? Body size depends on growth, which depends
on maximizing net energy and nutrient flows for the production of tissues at
seasonal scales across the range of the species. We measured thermoregulation
costs of body surface temperature (°C) and heat exchanges (W and W•m˗2)
of 350 adult and 345 adolescent Bison
from 19 herds in summer and winter along the Great Plains from Saskatchewan (52
°N) to Texas (30 °N). At the smallest scale, daily body surface temperature
increased with solar radiation and decreased with relative humidity and wind
speed, which is consistent with Kooijman’s dynamic energy budget theory. Total
surface heat transfer (W) increased with body mass (kg) at an exponent of 0.63
± 0.03, which is consistent Schmidt-Nielsen’s principal of surface area to
volume ratios (b=0.67). On an annual
scale, growth (kg•y-1) of adolescent Bison decreased with increasing total surface heat transfer (W) during
summer, which supports Speakman and Król’s heat dissipation limit theory. On the largest scale, heat flux was
weakly related to latitude in summer and winter for adolescent Bison, which provides support for
Bergmann’s rule and suggests a role for local primary production along the
Great Plains. Cooler summers are more optimal for Bison growth because of reduced heat loads during the growing
season. Rising temperatures are likely to constrain body size and productivity
of Bison and other large endotherms
in North America.