Microhabitat is important
Understanding how our warming climate affects vulnerable species is paramount. However, predicting responses is complicated because species are complex and can adapt or respond in different ways. Riddell et al. compared an age-old dataset on species richness in the Mojave with modern studies to measure climate-related changes in bird and small mammal communities. They found little change in mammal wealth or occupation, but large declines in birds. They attribute these differences to differences in microclimate probabilities: in particular, mammals can reduce temperature effects by digging, while birds are generally more exposed.
Science, this issue p. 633
Abstract
High exposure to warming from climate change is expected to threaten biodiversity as many species face extinction. Such exposure is often assessed for all taxa in a site based on climate projections, but species have different strategies for buffering against extreme temperatures. We compared changes in species occupation and richness at the location level of small mammal and bird communities in protected areas of the Mojave Desert using surveys over a century. Small mammalian communities remained remarkably stable, while birds declined significantly in response to warming and dehydration. Heat flux simulations identified different warming exposures for birds and mammals, which we attribute to microhabitat use. Climate projection estimates are unlikely to accurately reflect species exposure without taking into account the effects of microhabitat buffering on heat flux.