Modeling the suitability of Texas karst regions for infection by Pseudogymnoascus destructans in bats

Abstract

Abstract White-nose syndrome (WNS) is caused by the fungus Pseudogymnoascus destructans and has led to the deaths of millions of North American bats since it was first documented in New York in 2006. Since the first cases were recorded, WNS has spread rapidly across North America and is now confirmed or suspected in 40 US states and seven Canadian provinces. Often, the presence of P. destructans is detected in a cave or hibernaculum before signs of WNS manifest in the resident bat population, making presence of the fungus a more reliable assessment of potential epidemic spread than expansion of manifested WNS. An analysis of 43 cave internal climates across the state of Texas revealed a pattern of thermal suitability for P. destructans that correlated significantly with landscape (elevation, lithology) and external climate (mean surface temperature and precipitation). We generated a predictive model to assess the potential spread of P. destructans through Texas karst systems based on external features that correlate with suitable internal climates for fungal growth. Applications of this model to external climatic variables from 2019 showed seasonally varying patterns of suitability for fungal growth in select regions of Texas karst systems. Results from these surveys and models showed that internal climates of Texas caves are likely able to sustain the growth of P. destructans and could cause disease and resulting declines in Texas bats, and act as stepping-stones for the fungus, allowing it to travel southward into Mexican and Central American cave systems. The resulting work will inform researchers and natural resource managers of areas of significant concern to monitor for the spread of WNS.