Winter Activity of Coastal Plain Populations of Bat Species Affected by White-Nose Syndrome and Wind Energy Facilities

Abstract

Across the entire distribution of a species, populations may have variable responses to environmental perturbations. Many bat species experience mortality in large portions of their range during hibernation and along migratory paths to and from wintering grounds, from White-nose syndrome (WNS) and wind energy development, respectively. In some areas, warm temperatures may allow bats to remain active through winter, thus decreasing their susceptibility to WNS and/or mortality associated with migration to wintering grounds. These areas could act as a refugia and be important for the persistence of local populations. To determine if warmer temperatures affect bat activity, we compared year-round activity of bat populations in the Coastal Plain and Piedmont of North Carolina, USA, two regions that differ in winter temperature. We established six recording stations, four along a 295-kilometer north-south transect in the Coastal Plain, and two in the Piedmont of North Carolina. We recorded bat activity over two years. We supplemented our recordings with mist-net data. Although bat activity was lower during winter at all sites, the odds of recording a bat during winter were higher at Coastal Plain sites when compared with Piedmont sites. Further, bats in the Piedmont had a lower level of winter activity compared to summer activity than bats in the Coastal Plain that had more similar levels of activity in the winter and summer. We found high bat species richness on the Coastal Plain in winter, with winter-active species including those known to hibernate throughout most of their range and others known to be long distance migrants. In particular, two species impacted by WNS, the northern long-eared bat (Myotis septentrionalis) and tricolored bat (Perimyotis subflavus), were present year round in the Coastal Plain. The tricolored bat was also present year-round in the Piedmont. In the Coastal Plain, the long distance migratory hoary bat (Lasiurus cinereus) was active in the winter but not present during the other seasons, and the long distance migratory silver-haired bat (Lasionycteris noctivagans) was active primarily in the winter, suggesting the Coastal Plain may be an overwintering ground for these two species. We suggest that the winter activity exhibited by populations of bats on the North Carolina Coastal Plain has important conservation implications and these populations should be carefully monitored and afforded protection.

Variation in regional and landscape effects on occupancy of temperate bats in the southeastern U.S.

“…However, we detected MYLELUSE in three of the five regions (although they were not detected in many cells throughout each region), including one detection in the Coastal Plain. Although this detection was far outside their known historical range [ 56 ], these findings are consistent with a similar study in North Carolina [ 63 ]. The low detections of MYLELUSE and detections across the state likely led to the relatively low predictive performance (AUC = 0.62) of our model and suggests further research is needed on these species.…”

“…In contrast, we did not find support for a predicted effect of Region on LACI and MYAU occupancy. LACI appear to have more widespread summer distributions within our study area than expected ( Fig 5 ) as has also been found in North Carolina [ 63 ]. MYAU were not detected in many cells within the regions they are thought to occupy, possibly due to their preference for forested wetlands [ 16 , 60 ] that occur in small isolated patches and therefore were not heavily surveyed.…”

A statistical approach to white-nose syndrome surveillance monitoring using acoustic data

“…North American bat species face several contemporary conservation challenges throughout their range, including threats to habitat from loss and alteration of forested environments, and direct mortality from development of wind energy infrastructure [ 1 , 2 ]. However, transmission of Pseudogymnoascus destructans (Pd), the pathogen that causes white-nose syndrome (WNS), has emerged as the most serious threat to over a dozen species of North American bats that use caves and mines for hibernacula [ 3 ].…”

“…The presence of WNS in the Pacific Northwest opens another front in critical efforts to combat bat declines and shortens the timeline for implementing conservation strategies to protect vulnerable bat species. This effort is complicated by the fact that winter hibernation behavior for most western species is poorly understood [ 14 ], yet this is when WNS has the greatest negative impacts on bat populations [ 2 , 15 , 16 ]. Further, little is known about winter roost sites and activity patterns of many bats in western North America.…”

Acoustic Surveys for Bats are Improved by Taking Habitat Type into Account

“…Recently, this method has increased in popularity with the creation of automated software packages designed for species identification, with some offering real‐time species classification in the field (Russo and Voigt ). Such surveys are now commonly used to assess the presence of endangered species (e.g., Kaiser and O'Keefe ), effects of disturbance such as logging and wind turbines (e.g., Grider et al ), and as a long‐term population monitoring tool (e.g., Loeb et al ). However, the accuracy of the software is subject to debate.…”