Stable isotopic signatures in modern wood bison (Bison bison athabascae) hairs as telltale biomarkers of nutritional stress

摘要

Assessing the challenges faced by wildlife populations is key to providing effective management but is problematic when dealing with populations in remote locations. Analyses of the stable carbon and nitrogen isotope composition (expressed as delta C-13 and delta N-15 values) of sequentially grown tissues, such as hairs, can be used to track changes in the eco-physiology of organisms. We generated delta C-13 and delta N-15 values from sequentially sampled (n = 465) hairs taken from wood bison (Bison bison athabascae Rhoads, 1898) (n = 27). Samples were taken from individuals prior to and after their release from captivity into the lower Innoko-Yukon river area of Alaska in 2015. Twenty months after release, individuals had a distinct seasonal pattern in delta C-13 values. Hairs from individuals that experienced food scarcity or long-distance movement were sampled as case studies. Nutritional stress in these cases lead to a rise in delta N-15 values and a decrease in delta C-13 values. Applications of delta C-13 and delta N-15 analyses of bison tail hairs could provide wildlife managers a valuable and minimally invasive tool to better understand bison seasonal metabolic status and determine the historical health and behavior of living and dead individuals.