CBER Seminar - Dr Joe Williamson, UCL

Abstract: As the planet rapidly warms, the alteration of ecological interactions in novel environmental regimes will likely drive positive feedback loops, accelerating the pace and magnitude of biodiversity losses. Here I will propose that, without invoking such feedbacks, the risks of biodiversity loss should increase non-linearly with the magnitude of warming, simply because of the non-uniform way that biodiversity is distributed. Whether these non-uniformities are the uneven distribution of a species’ populations across a spatial thermal gradient, or the clustering of thermal limits in co-occurring species within an ecological community, we show that in both cases the emergent lack of variation in population warming tolerances drives non-linear increases in the risk of biodiversity loss. I take these ideas and apply them to a Spanish butterfly community, demonstrating that warming tolerances are strongly clustered across species, as estimated using both realised and fundamental niche limits. I will argue that non-linear increases in risks to biodiversity should be the null expectation under climate warming, and highlight the empirical research needed to understand the causes, commonness and consequences of clustered warming tolerances to better predict where, when and why non-linear biodiversity losses will occur.