Evolutionary Ecology of Mammalian Hibernation Phenology

Abstract

Hibernation is assumed to have evolved in response to environmental energy and/or water shortages, yet the environment in which it has most often been studied is the laboratory. Our understanding of the ecological and evolutionary significance of natural hibernation expression thus lags behind the impressive body of work that has been done on its physiological and biochemical mechanisms. In this chapter, I review studies that have been done on phenological variation in wild populations and argue for a tightened focus on individual variation. Climate change is altering temporal resource distributions worldwide and the impact that this may have on populations will depend on their ability to adjust their phenologies through phenotypic plasticity and/or microevolution. Making predictions regarding these two phenomena requires detailed information on the environmental and genetic contributions to, and the fitness consequences of, phenological variation. I describe each of these components, in turn, and briefly explain the analytical procedures used to calculate them. Although, to date, empirical information of this sort is relatively sparse for wild hibernators, recent studies have begun to provide it and the theoretical and analytical tools with which to undertake further study are becoming increasingly accessible. Through their application, a more thorough understanding of the role hibernation plays in the natural ecology of mammalian populations, and how these populations may be affected by climate change should be attainable.