GEOLOGICAL AND METEOROLOGICAL DATA FROM SITES INFECTED WITH WHITE-NOSE SYNDROME (WNS) BEFORE JULY 2011 IN EASTERN NORTH AMERICA

Numerous bat colonies in North America have recently experienced dramatic and unusual incidences of mortality. In these colonies, a white fungus (terrestrial saprophyte) named Geomyces destructans has been observed on the muzzles, noses, ears, and (or) wings of bats. Although it is not certain how and why these bats are dying, this condition has been named white-nose syndrome (WNS) and as of June 2011 it was estimated that more than a million bats had died from WNS. WNS was first documented in February 2006 at a cave in New York, and as of June 2011 WNS had spread north to Quebec, south to North Carolina, and west to Oklahoma. As with other infectious diseases, WNS probably has multiple modes of transmission, but some researchers have asked if certain geological or meteorological parameters may be more conducive to WNS (and thus may be used to predict the future spread of WNS).

Our compilation of data shows that there were at least 200 known WNS-infected sites in North America as of June 2011. The infected sites include both caves and mines at elevations ranging from 84 to 2,693 feet above sea level. Most infected sites are caves in Silurian-Devonian limestone, although the sites include locations in sedimentary, metamorphic, and igneous rocks of ages ranging from Precambrian to Jurassic. Thus, elevation, lithology, and strata age do not appear to restrict the distribution of WNS. Data on cave soil chemistry are lacking, but it is possible that certain cave soils may be more favorable than others for WNS (because G. destructans is a terrestrial saprophyte).

Published air temperature values from WNS-infected sites range from -3.3 to 15.6 °C, and humidity measurements range from 68 to 100 %. Previous laboratory experiments have indicated that G. destructans does not grow at temperatures above 20 °C, and thus it is possible that the spread of WNS may be restricted by a cave temperature threshold of 20 °C. Based on theoretical calculations and the sparse data that are available, this threshold of cave temperature probably lies near the southern border of the continental United States. Anecdotal field evidence suggests that the fungus prefers high humidity (although no laboratory studies on this topic have been published yet), and thus it is also possible that the spread of WNS may be restricted by some (as yet undetermined) threshold of low humidity.