Cooling requirements, climate change, and desert bird collapse

A study explores the relationship between evaporative cooling demands and climate-driven species declines. Climate change will likely increase the risk of extinction for many species, but the physiological mechanisms underlying climate-driven extinctions remain unclear. Eric Riddell, Steven R. Beissinger, and colleagues used simulations of animal thermoregulation to evaluate whether the amount of water needed to keep cool played a role in the climate-driven collapse of the Mojave Desert bird community over the past century. The probability of species persisting at a given site between 1906 and 2015 was lowest for the hottest and driest sites. Using a model of heat flux, the authors estimated the change in cooling cost, or the amount of evaporative cooling needed to maintain constant body temperature, during the hottest month of the year in the Mojave Desert for 50 bird species over the past century. Increased cooling cost was associated with declining species occupancy, particularly for insectivorous and carnivorous species that get most of their water from prey and for large species for which cooling costs increased the most. Based on climate forecasts, the authors estimated that water requirements for Mojave birds would increase by 50-78%. The results suggest that water requirements may make species declines more likely in a warming and drying climate, according to the authors.

Article #19-08791: “Cooling requirements fueled the collapse of a desert bird community from climate change,” by Eric A. Riddell et al.

MEDIA CONTACT: Eric A. Riddell, University of California, Berkeley, CA; tel: 404-313-0682; e-mail:

[email protected]

; Steven R. Beissinger, University of California, Berkeley, CA; tel: 510-499-5516; e-mail:

[email protected]

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