Abstract 120 - Hair, hormones and disturbance; a pilot study using a non-invasive approach to assess physiological function in free-ranging grizzly bears.
Kristenn Magnusson, Government of Yukon ProfessionalSalon 8/9
Kristenn Magnussom, Jodie Pongracz, Piia Kortsalo, Abbey Wilson, Sarah Michaud,
Karen Graham, Darío Fernández-Bellon, Gordon Stenhouse, Marc Cattet
Understanding how environmental drivers affect physiological processes in individual animals is
germane to forecasting how wildlife populations will tolerate environmental change. When
environmental conditions are within preferred ranges, physiological processes function without
excess energy demands. Beyond range thresholds, energy demands increase, tolerance
becomes time limited, and impairment of physiological processes is inevitable. As more
individuals exceed their thresholds, productivity and survival decrease at the population level
and eventually lead to a commensurate decline in abundance. In this pilot study, we are
measuring and comparing steroid and thyroid hormone levels in hair as an assessment of
physiological function in grizzly bears (Ursus arctos), using samples collected non-invasively
from two study areas, one with high anthropogenic disturbance in Alberta (36 bears) and other
from a relatively undisturbed, remote area in the Yukon Territory (41 bears). Our objectives are
to determine and compare hormone levels indicative of physiological processes (specifically
stress, reproduction, and energy metabolism) between study areas, and to evaluate specific
environmental variables as potential drivers of physiological processes. We identified unique
individuals and their sex by analyzing DNA extracted from hair follicles. Using a liquid
chromatography-multiple reaction monitoring/mass spectrometry metabolomics assay, we
determined the concentrations of 27 hormones in hair samples weighing as little as six
milligrams (20-30 hairs). Concentrations of specific hormones within five major hormone
classes differed significantly between study areas and between sexes. Temporal trends were
also evident for some hormones. For the next phase of our study, we are evaluating a suite of
landscape composition and disturbance measures as potential determinants of steroid and
thyroid hormone levels in hair and, more generally, physiological function in grizzly bears.
