How climate change can affect the dynamics of stage-structured seasonal breeders.

In order to be useful in assessing the effects of climate change on biological populations, mathematical models have to adequately represent the life cycle of the species in question, the dynamics of and interactions with its resource(s), and the effect of changing environmental conditions on their vital rates. Due to this complexity, such models are often analytically intractable. We present here a consumer-resource model that captures seasonality (summer and winter), with synchronously reproducing consumers (birth pulse), structured into non-reproductive juveniles and reproductive adults, and that remains analytically tractable. Our model is motivated by hibernating mammals, such as marmots, ground squirrels, or bats, some of which live in high altitude regions where the effects of climate change are stronger than elsewhere. One stage-specific impact of climate change in those species is that juveniles may benefit from warmer winters while adults may suffer. We explore various aspects of how this differential response to climate change shapes population dynamics from stable populations to cycles and chaos. We show that the qualitative relationship between winter temperature and winter mortality has a significant effect on the model dynamics, hence informing empiricists of required data to assess the effect of climate change on these species. Our results question the long-standing expectation that species with slower life histories are necessarily more strongly affected by climate change than species with faster life histories.