Are microclimate conditions in El Malpais National Monument caves in New Mexico, USA suitable for Pseudogymnoascus growth?

White-nose syndrome (WNS) is a bat disease caused by the fungal pathogen Pseudogymnoascus destructans, which thrives in cold and very humid environments where bats frequently hibernate. Conidia of Pseudogymnoascus species are often documented on bats prior to the onset of WNS, but characterization of high-risk areas defined by microclimate cave conditions have been lacking. Investigating the occurrence of this fungal genus and appropriate environmental conditions to support P. destructans in southwestern U.S. caves is key to understanding the sites most likely to be impacted by WNS. Microclimate conditions in ten caves at El Malpais (ELMA) National Monument in New Mexico, USA were recorded using i-Button data loggers during the winters of 2011–2014 to assess appropriate environmental conditions (temperature and relative humidity) for P. destructans and other Pseudogymnoascus species. Optimal microclimate conditions for P. destructans and other psychrophilic fungi were found in all the caves with at least 50% of the caves identified as high-risk areas. Pseudogymnoascus species were detected in 70% of the caves using culturing methods and PCR, but no soil samples were positive for P. destructans using real-time PCR in soil and guano samples. Pseudogymnoascus destructans has a recognized range of appropriate temperatures and relative humidity for growth and cave microclimate can help define high-risk areas. This study offers resource managers guidance for establishing priority monitoring areas in their bat caves to determine which bat species are at higher risk.