Microhabitat matters
It is of utmost importance to understand how our warming climate affects vulnerable species. However, predicting responses is complicated because species are complex and can adapt or respond in different ways. Riddell et al. compared a century-old dataset on species richness in the Mojave to modern surveys to measure climate-related changes in communities of birds and small mammals. They found little change in mammalian wealth or occupation, but large decline in birds. They attribute these differences to differences in microclimate opportunities: Mammals can specifically mitigate the temperature influence by digging, while birds are generally more exposed.
Science, this issue p. 633
Abstract
High exposure to global warming and global warming is expected to threaten biodiversity by pushing many species to extinction. Such exposure is often assessed for all taxa in one place due to climate projections, but species have divergent strategies for buffering at extreme temperatures. We compared changes in species population and wealth of small mammal and bird communities in protected areas of the Mojave Desert using surveys spanning a century. Small mammalian communities remained remarkably stable, while birds declined significantly due to warming and drought. Heat flow simulations have identified different exposure to heat for birds and mammals, which we attribute to the use of microhabitats. Estimates of climate projections are unlikely to accurately reflect species exposure without offsetting the effects of microhabitat buffering on heat flow.