Stress and reproductive hormones reflect inter-specific social and nutritional conditions mediated by resource availability in a bear–salmon system

摘要: Food availability can influence the nutritional and social dynamics within among species. Our investigation focused on grizzly black bears in coastal British Columbia, Canada, where recent dramatic declines their primary prey (salmon) raise concerns about potentially negative effects bear physiology. We examined how salmon relates to stress reproductive hormones (n = 69) (n = 68) using cortisol testosterone. In hair samples from genotyped individuals, we quantified consumption stable isotope analysis hormone levels by enzyme immunoassay. To estimate biomass available each bear, developed a spatially explicit approach based typical home-range sizes. Next, compared relative importance of male an information theoretical approach. Cortisol was higher individuals that consumed less salmon, possibly reflecting stress. bears, better predicted than consumption; specifically, areas years with low showed levels. This indicates is more strongly influenced socially competitive environment mediated requirements. both species, testosterone generally decreased increasing availability, when were abundant. Differences between species could relate different requirements, densities behaviour and/or habitat use. present conceptual model inform further investigations this other systems. approach, which combines data multiple dietary spatial corresponding year growth, provides promising tool for evaluating responses broad spectrum wildlife changes food or environmental conditions.