Fine-scale Climates and Evolution Alter Species Responses to Climate Change

Predictions suggest that climate change could cause the extinction of up to a million species. However, scientists debate the accuracy of these predictions. In this dissertation, I explore whether often-ignored aspects of climate and biology alter predictions of climate change impacts. In Chapter 1, I show that studies predicting extinction risk under climate change ignore important aspects of climate by using climate data with coarse spatial and temporal resolutions. In Chapter 2, I propose that the degree to which climates vary over space and time in a region can predict the vulnerability of species to climate change. I suggest that populations living in regions with high spatial climatic variation (e.g., mountainous regions) should be less vulnerable to climate change and identify a tension between various effects of temporal climatic variation on climate change responses. In Chapter 3, I use Daphnia magna (an aquatic crustacean) in freshwater rock pools to evaluate whether populations from locations with greater temperature variation have adaptations that make them less vulnerable to climate change. Despite observing genetic variation and plasticity in a key thermal tolerance trait, I did not observe differences among populations as predicted. Moreover, I demonstrate a loss of evolutionary potential under warm temperatures, which could increase vulnerability. In Chapter 4, I map temperature variation at a sub-meter resolution in freshwater rock pools and demonstrate that this fine-scale temperature variation significantly alters predictions of climate change impacts on biodiversity. I also show that protecting cool microclimates might be a highly efficient means of conserving regional biodiversity under climate change. In Chapter 5, I use a literature review to suggest that evolution will likely alter species range dynamics under climate change, highlight potential conservation implications, and suggest a method for rapid learning in eco-evolutionary climate change biology. Last, in Chapter 6, I use lab experiments with archaea to provide experimental support of the community monopolization hypothesis, which is an eco-evolutionary dynamic that could increase extinction risk under climate change. This body of work increases our understanding of where and why species will be vulnerable to climate change and provides important insights for conservation biologists