Despite living in the same part of the Mojave Desert, and experiencing similar conditions, mammals and birds native to this region experienced fundamentally different exposures to climate warming over the last 100 years, a new study shows; small mammal communities there remained much more stable than birds, in the face of local climate change, it reports. The study presents an integrative approach to understanding the climate vulnerability of biodiversity in rapidly warming regions. Exposure to rising temperature extremes threatens species worldwide. It is expected to push many ever closer toward extinction. Thus, understanding how species respond to increased warming is crucial to predicting risks and conserving biodiversity. Predictions of climate vulnerability assume that those species within a shared environment experience similar magnitudes and rates of exposure to extreme heat and respond in similar ways. However, species are complex and exhibit a diverse array of distinct behavioral and physiological adaptive strategies to buffer against environmental change, which could translate into different exposure risks, even across co-located species. Leveraging a century-old historical dataset on species richness, animal surveys of the same locations surveyed now, and detailed ecological modeling, Eric Riddell and colleagues compared the responses of bird and small mammal communities to climate warming in the Mojave Desert. The authors found that, despite sharing a similar location and comparable physiological and ecological requirements, mammals and birds experienced fundamentally different exposures and responses to climate warming and drying over the last 100 years. While small mammal communities have remained remarkably stable in the face of change, bird occupancy and species richness have suffered dramatic declines. Riddell et al. attribute these differences to variations in each groups' ability to exploit microclimate opportunities. While small mammals can mitigate rising temperatures by burrowing into the cool earth, birds are generally far more exposed, and thus likely more vulnerable to climate warming. Modeling approaches that combine physiology and behavior are needed to more accurately predict a species' persistence in the face of climate change, suggest the authors.
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Journal
Science