Comparative Life-Cycle Analyses Reveal Interacting Climatic and Biotic Drivers of Population Responses to Climate Change

Responses of natural populations to climate change are driven by how multiple climatic and biotic factors affect survival and reproduction, and ultimately shape population dynamics. Yet, we lack a general understanding of the role of such mechanisms in moderating climate-change impacts across different species. Here, we synthesize how the joint effects of climate and biotic interactions on different vital rates impact population change, using 41 species from trees to primates. We show that the effects of multiple climatic drivers tend to exacerbate population responses to climate change in most species. Importantly however, density feedbacks consistently buffer the effects of climate drivers on populations. In all species considered in our analyses, such interactions among climate and density had starkly different effects depending on the age, size, or life-cycle stage of individuals, highlighting that climate-change impacts can hardly be inferred from single drivers or ages or life-cycle stages, regardless of the life-history of species. Our work thus advances our ability to make generalizations about key pathways of climate-change impacts on populations.