Review written by Anne Larsen (2026, EEB)
There is a widespread misconception that deserts, arid and extreme in climate, are unaffected by climate change. The truth is that deserts are disproportionately impacted by climate change and are projected to see great changes in the distributions of fauna and the behavior of such species due to current warming trends. Though both cold and warm deserts will be affected by these changes, warm deserts have already sustained damage. Indeed, the surprisingly diverse region has suffered much due to climate change, and the ecosystem harbored by this biome constantly lives at its physiological limits. Further changes to these regions would create conditions even more extreme than those to which these species have already adapted, possibly leading to extinction.
The Wilcove group, a lab at Princeton University that investigates policies, economics, and the ecology surrounding conservation, explores the impacts of climate change on a class of organisms that is especially sensitive to it: desert birds. Because most avian species are active during the day and cannot take advantage of thermally buffered microsites–like burrows–these birds are constantly at the mercy of the sun and arid climate[5, 6].
In order to study how desert birds are impacted by the changing climate, Ma et al. of the Wilcove group created a model that goes beyond simply measuring changes in desert air temperature (or ‘Tair’)–the measure that is currently the standard in the field. The model includes temperature data from microclimates and future climate projections, and also integrates desert physiology: in this case, birds and two specific attributes that allow them to survive in such an extreme climate. These attributes are Total Evaporative Water Loss (TEWL) per average day of the hottest month of the year and Acute Dehydration Risk (ADR), the maximum water loss in three consecutive hours per average day of the hottest month of the year. They chose these metrics because maintaining water balance is necessary for survival in the desert; retaining water is integral for hydration, but mechanisms like sweating are necessary for keeping cool in the desert heat[6, 7]. The inclusion of physiological metrics in their study is quite novel, as most studies solely consider the impacts of Tair when discussing the effects of climate change on desert regions.
To measure the susceptibility of bird species in desert regions, the Wilcove lab created a world map that organizes deserts by terrestrial habitat type and amount of rainfall. Ma et al. measured the overall impact of climate change on TEWL and ADR by estimating the changes in those features by using current averages and predicted future averages. The Wilcove group found that climate change has a high impact on the average TEWL and Tair in the Saharo-Arabian region, while ADR was not heavily impacted. However, when the current and predicted averages of Tair, TEWL, and ADR were considered together, areas spanning from the Saharo-Arabian region all the way to Central Asia find themselves at a severe level of impact.
Additionally, the Wilcove group used their map to predict potential refugia spaces, which are regions in the desert with high biodiversity and low impact from climate change. They discovered that many of these regions pinpointed by their model that previously housed a thriving variety of species were not protected by existing laws and regulations. Without protection from land use and exploitation, desert birds are backed into a corner: on one hand, they must escape to these refugia regions to evade the effects of climate change, but on the other hand, many of these regions are not legally protected[8, 9]. In other words, even when desert birds flee to refugia regions and escape the harsher impacts of climate change, they are not always protected from disturbances from humans.
There was considerable variation in the impacts of climate change on different regions of refugia, and the team found that the magnitude of impact was dependent on whether or not TEWL and ADR were considered alongside Tair, rather than only factoring in air temperature. Using the physiological metrics in their model amplified the predicted effects of climate change in refugia regions, though it did not alter the projected placement of refugia regions, which tended to fall on coastlines.
This study highlights the importance of using biological factors, such as TEWL and ADR, in climate change models. Relying on metrics like air temperature is currently the norm, yet it does not paint a complete picture of the effects on climate change. The use of such factors in a climate change model completely altered projected climate change impact, which begs the question of how intricately the impacts of climate change are intertwined with ecological features, rather than simply topographical. By comparing past, current, and projected air temperatures with water balance maintenance, the Wilcove group showed that warm desert regions are yet another victim of the warming world.
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