Climatic niche divergence drives patterns of diversification and richness among mammal families

A major goal of evolutionary biology is to understand why clades difer dramatically in species richness. A key to this challenge is to uncover the correlates of variation in diversifcation rate (speciation – extinction) among clades. Here, we explore the relationship between diversifcation rates and the climatic niches of species and clades among 92 families of terrestrial mammals. We use a time-calibrated molecular phylogeny of mammals and climatic data from 3335 species. We show that considerable variation in net diversifcation rates among mammal families is explained by niche divergence (59%) and rates of niche change (51%). Diversifcation rates in turn explain most variation in species richness among families (79%). Contrary to expectations, patterns of diversifcation are not explained by diferences in geographic range areas of clades, nor by their climatic niche position (i.e. whether they are primarily tropical or temperate). Overall, these results suggest that speciation through climatic niche divergence may help drive large-scale patterns of diversifcation and richness. Our results help explain diversifcation patterns in a major clade of vertebrates, and suggest that similar underlying principles may explain the diversifcation of many terrestrial cladesThis work was supported by the Spanish Ministry of Economy and Competitiveness and ERDF funds (grants CGL2013-43350-P and CGL2016-76637-P, and fellowship IJCI-2014-20881 to C.G.R.) and Xunta de Galicia (PhD fellowship ED481A-2015/074 to A.C.I and postdoctoral fellowship POS-A/2012/052 to C.G.R.)S

Global predation pressure redistribution under future climate change

How climate affects biotic interactions is a question of urgent concern1-3. Theory predicts that biotic interactions are stronger at lower latitudes4-6. However, the role of climate in governing these patterns is typically assumed, rather than explicitly tested. Here we dissected the influence of climatic descriptors on predation pressure using data from a global experiment with model caterpillars. We then used projections of future climate change to predict shifts in predation pressure. Climate, particularly components of temperature, explained latitudinal and elevational patterns of predation better than latitude or elevation by themselves. Projected predation pressure was greater under higher temperatures and more stable climates. Increased climatic instability projected for the near future predicts a general decrease in predation pressure over time. By identifying the current climatic drivers of global patterns in a key biotic interaction, we show how shifts in these drivers could alter the functioning of terrestrial ecosystems and their associated services