1. Climate change is expected to shift species distributions as populations grow in favorable habitats and decline in harsh ones. Montane animals escape warming conditions at low elevation by moving upslope, but may be physiologically constrained by conditions there. Effects of elevation were studied for montane populations of the leaf beetle Chrysomela aeneicollis, where allele frequencies at nuclear genes and the mitochondrion vary along latitudinal and altitudinal gradients. 2. A population presence survey conducted along...

Latitudinal and elevational richness gradients have received much attention from ecologists but there is little consensus on underlying causes. One possible proximate cause is increased levels of species turnover, or β diversity, in the tropics compared to temperate regions. Here, we leverage a large botanical dataset to map taxonomic and phylogenetic β diversity, as mean turnover between neighboring 100 × 100 km cells, across the Americas and determine key climatic drivers. We find taxonomic and...