FINDING PSEUDOGYMNOASCUS DESTRUCTANS IN TWO SIGNIFICANT NEW MEXICO BAT HIBERNACULA
|Debbie C. Buecher; Buecher Biological Consulting; firstname.lastname@example.org; Diana Northup, Marikay Ramsey, Jennifer Hathaway
White-nose syndrome (WNS) is a novel bat disease caused by the fungus Pseudogymnoascus destructans (Pd). The visual manifestation of Pd is white fungal growth around bats’ noses, on forearms and tail membranes. It was first observed on hibernating bats in a cave in New York during winter 2006-2007. This invasive fungus prefers sites with cold, humid conditions, which bats also choose for winter hibernation. It is a keratin-loving fungus that breaks down cell walls in bats’ membranes – disrupting physiological functions for the bat and frequently leading to their death. Since 2009 we have monitored the microclimates in two gypsum caves in south-central New Mexico (NM) managed by BLM. Despite being caves in the arid Southwest, these caves have optimal microclimate for Pd to flourish. Cave myotis (Myotis velifer) use these two sites to hibernate in tight clusters, increasing the chances for fungal spores spreading among individuals. In mid-April 2021 we entered these sites to swab bats for Pd during which we found bats with visible fungus on their noses within clusters of conspecifics. This is the first documentation that Pd is definitely and visually in NM. We will discuss the possible implications and management issues of Pd for NM bats.
THE EFFECTIVENESS OF BAT GATES FOR CONSERVING COLONIES AND POPULATIONS OF BATS IN WESTERN U.S.
|Rick E Sherwin; Christopher Newport University; email@example.com; Jason Williams, Linda DeLay, Casey Devine-Rosser
The protection of subterranean roosts deemed critical for the long-term conservation of bats has become increasingly common throughout the United States. In the western U.S. the majority of bat gates have been installed to protect abandoned mine openings during Abandoned Mine Reclamation activities (AML). Variation in local geology, portal stability, access, scope, and reclamation budgets has resulted in a range of gate styles, materials, and installation methods. While the unifying objective of gate installation is the long-term conservation of bats and concurrent elimination of human access to dangerous abandoned mines, there has been a paucity of post-gating monitoring to determine the long-term effectiveness of bat gates in general, and of different gate types and materials more specifically. As a result, inference of bat gate effectiveness is largely anecdotal. Typically attempts to measure gate "success" are based on casual observations, collected from a small geographic area and over limited period of time. While these observations provide a platform from which research on gate success can be developed, the observations themselves are not data and should be treated accordingly. This presentation includes data collected throughout the western United States in years preceding treatment, during treatment, and in the years following treatment at several large-scale AML projects. The goal of this study was to understand the overall effectiveness of AML mitigation programs for maintaining use of abandoned mines by bats, facilitating standardization of best management practices for maintaining bat populations in historically mined landscapes.
E-BIKE HIGH FREQUENCY NOISE AND POTENTIAL IMPACTS TO ROOSTING BATS
|Dave S Johnston; H. T. Harvey & Associates; firstname.lastname@example.org;
Bats are acutely sensitive to changes in their sound environment and can react to relatively quiet noise if it is foreign to them and stimulates a stress response. Additionally, the frequency of the noise is also important because individual species of bats have different sensitivities to various noise frequencies. To determine if e-bikes produce high frequency sounds that potentially disturb and impact bats, we recorded three e-bike models and two conventional bike models with high frequency and low frequency microphones spaced at 10 ft., 20 ft., 40 ft., and 80 ft. away from passing e-bikes/conventional bikes in each of four modes (pedal slowly, pedal fast, coasting, and braking). Based on the modelled attenuation of noise to ambient noise levels for different phonic groups of bats, we recommend buffer distances between e-bike traffic to day roosting bats of 100 ft. for 20 kHz bats, 107 ft. for 30 kHz bats, 231 ft. for 40 kHz bats and 134 ft. for 50 kHz bats.
FORAGING ECOLOGY OF THE HAWAIIAN HOARY BAT
|Dave S Johnston; H. T. Harvey & Associates; email@example.com; Kristin Jonasson, Brad Yuen
We radio-tracked 16 bats on 109 nights from June 2017 – September 2018. We calculated the 95% kernel foraging ranges (FRs) and 50% kernel core use areas (CUAs) in R. We used blacklight traps to sample insects in each of the 9 habitat types and determined the diets of bats using a DNA barcode library and analysis of each bat’s guano. Bats spent more time foraging in gulch, low-density developed, and grassland habitats, and differences existed between months (P < 0.01). The mean CUA was 3,991 hectares and the mean FR was 17,362 hectares. Bats ate primarily moths (68%), as well as flies (12%), termites (9%), crickets and katydids (5%), beetles (4%), and true bugs (2%). Native and nonnative insects were eaten, and bats were somewhat selective in prey species given the abundance of particular species found in the insect samples but not consumed. Agricultural vegetation, grassland, and low-density developed habitats had the highest dry weight values for insects, while the lowest values were from the forest woodland and high-density developed habitats. Our data suggest foraging flexibility in the species with the use of habitat types changing during different seasons.
INVESTIGATING DRIVERS OF SUMMER BAT ACTIVITY IN CALIFORNIA REDWOOD FORESTS
|Chelsea L. Andreozzi; University of California, Berkeley; firstname.lastname@example.org; Adina M. Merenlender
Western North American bat populations are increasingly at risk from the emerging threats of climate change and the fungal disease white-nose syndrome, leading to a heightened urgency to understand western bat ecology and habitat use. At least thirteen species of bats, including three California Species of Concern and seven additional species at risk, inhabit coast redwood forests. Species activity patterns vary significantly across these forests, but the mechanisms behind bat distribution patterns are largely unknown. In summer 2019 and summer 2020, we conducted passive acoustic monitoring at 20 coast redwood forest sites in Mendocino and Sonoma Counties, including both old-growth groves and working forests. Study sites reflected the coastal gradient of fog-influenced climate. At each site, detectors were deployed in the riparian corridor for a minimum of four consecutive nights during each of four monitoring rounds. We used statistical models to relate species activity to environmental variables, including canopy height, Timber Harvesting Plan records, actively logged microclimate, historical climate, and stream channel area. Our study demonstrates that young, working forests also serve as critical habitat for sensitive bat populations, and managing these forests for bats may thus be as important for species conservation as managing in mature, protected areas.