Abstract

The sky island forests of the southwestern United States are one of the most diverse temperate forest ecosystems in the world, providing key habitat for migrating and residential species alike. Black bear, bighorn sheep, mule deer, and wild turkey are just a few of the species found in these isolated mountain ecosystems that rise out of the desert landscape. However, recent droughts have crippled these ecosystems, causing significant tree death. Climate predictions suggest that this region will only face hotter and drier conditions in the future, potentially stressing these ecosystems even further. Simple models predict that vegetation will move to cooler and wetter locations in response to this warming. However, species responses will likely be more complex than these models show, as vegetation navigates other ecological stressors such as elevation change and water availability.

In order to better predict how vegetation will move in response to future warming, a more robust understanding of how drought and temperature impact tree survival is needed. Focusing on three sky island habitats in western Texas, this project sought to identify the key traits influencing current distributions of forest tree species, determine the susceptibility of these species to drought and temperature, and develop fine-scale, localized climate projections that model future conditions for the study area. This information is meant to be used to predict how species might shift location in response to warmer and drier future climates, enabling managers to make more robust decisions that will preserve sky island forests in the face of a changing climate.