Ecology & Conservation of Bats I

Contributed Oral Presentations

SESSION NUMBER: 20

Contributed paper sessions will be available on-demand for the duration of the conference, then again at the conclusion of the conference.

 

Northern Long-Eared Bats on the Mid-Atlantic Coastal Plain of North Carolina and Virginia
Jesse De La Cruz
Although well documented throughout much of its range, data on probable presence, activity levels, and habitat selection of northern long-eared bats (Myotis septentrionalis) is limited on the Coastal Plain of the Southeast and mid-Atlantic, where populations have recently been discovered. During 2016-2020, we monitored 170 acoustic recording stations on the Coastal Plain of eastern North Carolina and Virginia. Across all years, echolocational passes identified as northern long-eared bats were detected at 81 (48%) recording stations. Zero-inflated negative binomial models were used to examine the effect of various weather-related, biological, and ecological variables on nightly northern long-eared bat activity. While present the entire year, suggestive of a non-traditional overwinter dynamic, northern long-eared bats were more active during warmer nights of the early maternity season (i.e., Julian days 60-180) and in areas containing high proportions of contiguous woody wetlands (35%) and evergreen forests (25%). Conversely, activity was negatively related to high wind speeds, increasing proportion of upland forests (i.e., deciduous and mixed forests), and anthropogenic development. Our results suggest the need to conserve areas of high overall forest cover (≥ 50%), specifically large tracts of woody wetlands. Additionally, minimization actions for land management (i.e., seasonal clearing restrictions around maternity areas) that may affect northern long-eared bats will likely require a shorter action window to ensure effectiveness on the Coastal Plain than in the interior Appalachians and Midwest regions.
Bat Winter Day-Roost Site and Foraging Activity on a Pyric Landscape in Northern Florida
Marcelo H. Jorge; Sam Freeze; Katie Gorman; Hila Taylor; Mike True; Michael J. Cherry; W. M. Ford
Foraging and day-roost habitat selection by tree bats during the winter season and their response to dormant season fires is poorly understood in the Southeast. During late February and then again in early December of 2019, we mist-netted and radio-tagged 13 Seminole bats (Lasiurus seminolus) and simultaneously deployed 34 acoustic detectors, on Camp Blanding Joint Training Center in Florida. Radio tagged bats were tracked daily to day-roosts for a week whereas detectors recorded for a month during each survey period. Audio files were identified to species using Kaleidoscope 5.1.0 and nightly activity levels for bat species was examined using a generalized linear mixed model with all possible combinations of our fire history and environmental variables. All bat activity increased with increasing temperatures and with increasing time since fire. Seminole and hoary (L. cinereus) bats had greater activity in pine forests whereas red bats (L. borealis) had greater activity in deciduous forests. Seminole and red bats increased activity near mesic locations whereas hoary bat activity decreased. Lastly, red bats had greater activity during the February survey period compared to December. Most Seminole bats roosted high in the canopy of dominant water oaks (Quercus nigra) or pines, i.e., loblolly pine (Pinus taeda), slash pine (P. ellioti) or longleaf pine (P. palustris), though some bats roosted in the foliage of small red bay (Persea borboni) under the forest canopy. Of the 57 day-roosts we observed, 89% were located in mesic hardwood sideslopes or bottomlands where dormant season prescribed fires are infrequently applied and occurred at low-intensity. Our results suggest that Seminole bats choose day-roosts that maximize solar exposure while also minimizing risks associated with fire and all species foraged in areas with less frequent fires or longer times since fire within this frequently burned landscape during the dormant season.
Using Next-Generation Sequencing to Evaluate the Diet of Big Brown Bats in the Mid-Atlantic Region
Sabrina Deeley; Lin Kang; Pawk Michalak; Eric Hallerman; W. Mark Ford
Next-generation sequencing (NGS) can generate large genetic data sets in a cost-effective manner, and it has been used to identify prey items within bat feces. Big brown bat (Eptesicus fuscus) diet has been well-studied throughout North America with visual identification methods of prey items in feces, typically from day-roost colonies in rural settings. The purpose of our analysis was to document the diet of big brown bats within fragmented and urban mid-Atlantic landscapes and to assess the applicability of NGS for this purpose. Concordant with our expectations and from previous diet studies on the bat, we observed a high abundance of Coleoptera (beetles) and low abundance of other orders in big brown bat diets. Although we documented high diet variation among areas along rural to urban gradients, we did not note explicit effects of urbanization or forest fragmentation upon the diversity of insect prey items per se. Though an improvement over visual food habits techniques, we suggest caution in interpreting NGS results in diet studies, as we noted numerous observations of environmental DNA within the results and that different sorting methods impacted the presence and relative abundance of taxa within their diet.
Urbanization and Bats
Shannon Pederson
White Nose Syndrome (WNS), caused by the psychrophilic fungus, Pseudogymnoascus destructans (Pd), has decimated hibernating bat populations across much of North America. Pd physically irritates bats during hibernation, resulting in abnormal behavioral changes, premature usage of stored energy, dehydration, and finally death. Since Pd requires cold and humid environments to survive, its impact on bat populations may differ in urban “heat islands” – warmer and drier climates in urban areas compared to natural areas. Furthermore, urban structures, planted trees, artificial lights, and additional water sources may inadvertently offer bats roosting, commuting, and foraging habitat. Therefore, we hypothesized that urban areas within a WNS-­positive region could serve as habitat for bats and lead to increased total bat activity, WNS-sensitive bat species activity, or overall bat species diversity. We deployed bat acoustic detectors, insect traps, climate loggers, light loggers, and sound meters every week from March through October from 2015-2017 among three urbanization levels (high, medium, and low) in the Mid-Atlantic States of Virginia, Maryland, and Delaware. We recorded nearly 300,000 echolocation passes over 1,200 nights. Kruskal-Wallis tests revealed high urbanized areas held higher bat species diversity, total bat activity, and activity of one WNS-sensitive species (Tri-colored bat) than other urbanization levels. GLMM modeling results will be presented to highlight key habitat features influencing urbanization’s surprising benefit on bat species diversity and species-specific activity and therefore justify recommendations for land managers and homeowners.
U.S. National Park Visitor Attitudes Towards Bats and Knowledge of White-Nose Syndrome
Hannah G. Shapiro; Adam S. Willcox; Emma V. Willcox; Michelle Verant
Stakeholder perceptions are essential to creating effective conservation plans, especially when these efforts focus on taxa that have a history of negative preconceptions, like bats. In the U.S., one organization that has worked to change people’s perceptions of bats is The National Park Service (NPS). The NPS offers a variety of educational programming on bats, including written educational material and ranger interpretive programs. These efforts to educate the public about bats have only increased with the discovery and spread of white-nose syndrome (WNS), an invasive fungus that has killed millions of bats in North America. Despite the NPS’s extensive efforts to educate the public, managers lack information on visitor perceptions and knowledge of bats. This study examined national park visitor attitudes towards bats, knowledge of bat ecology, and knowledge of WNS to determine which of these factors influenced visitor support of bat conservation efforts in national parks. During the summer of 2019, we surveyed 1365 visitors in eight national park areas: Oregon Caves, Lava Beds, Carlsbad Caverns, El Malpais, Wind Cave, Jewel Cave, Mammoth Cave, and Cumberland Gap. Quantitative analysis revealed that visitors’ support for bat conservation in national parks was influenced by their positive attitudes towards bats, recognition of ecosystem services bats provide, and identification of WNS as a threat. However, park disparities in visitor recognition of WNS and visitors’ overestimation of bats’ importance to suppressing mosquito populations revealed that there are still gaps in the parks’ educational efforts. As bat management changes over the coming decade, understanding visitor perceptions of bats and integrating this information into cave management plans will be critical for the NPS to achieve its management goals focused on enhancing recreation and conservation in environments shared by humans and bats.
Long Term Acoustic Monitoring of Migratory Tree Bats on Virginia’s Atlantic Coast Barrier Islands – Implications for Offshore Wind Development
Michael True; Rick Reynolds; W. Mark Ford
Tree bats (Lasiurus spp., Lasionycteris noctivigans) comprise most wind turbine collision fatalities among eastern North American bats, particularly during the autumn period of southward migratory movement, mating, and juvenile dispersal. Evidence points to an Atlantic coastline concentration of southward migrating tree bats near or offshore from the Northeast. However, data gaps relative to coastal or offshore behavior exist in mid-Atlantic areas where new offshore wind energy projects are planned or may be planned. Although curtailment is effective to minimize risk to bats, understanding variables that drive occurrence near potential wind energy sites may aid development of best management practices to balance bat protection and minimize loss of energy production. Our objectives were to 1) model the influence of season, weather conditions, vegetational structure and distance to the mainland of Virginia’s Atlantic Coast barrier islands on tree bat occurrence, and 2) provide a tool to predict occurrence of tree bat that may be used to inform curtailment strategies. We used long-term (2012-2019), multi-season acoustic monitoring detectors on five barrier islands to measure bat occurrence. Within a Generalized Additive Model framework with bat occurrence as the response variable, we found a negative relationship with wind speed, positive relationship with temperature, and a bi-modal, seasonal effect of day of the year on each island monitored. Although our study inference is limited currently to near-shore environments, our results suggest that our model predictions can provide meaningful temperature, wind, seasonal and other environmental thresholds to inform “smart” curtailment strategies for wind developers.
Illuminating Knowledge Gaps: Effects of Artificial Lights on Bats
Jose Gabriel Martinez-Fonseca
Artificial lighting at night (ALAN) is an anthropogenic disturbance currently impacting 20% of the Earth’s surface. ALAN alters the interactions of organisms across many trophic levels and has been shown to have negative consequences for several species. Bats, in particular, may be especially sensitive to ALAN due to most species’ nocturnal habitats. Bats provide a variety of ecosystem services that could be altered with exposure to light pollution, especially in areas where bats have diverse diets. We conducted a systematic review regarding ALAN impacts on bats to identify gaps and bias in the literature, summarize management and research implications, and suggest standardized metrics for ALAN research in relation to bats. We found that most studies focused on short term impacts (< 1 year; 66.6% of papers) on European bat species (67.4% of papers) detected by acoustic monitoring (80.9% of papers). Many metrics such as distance from sampling locations and light source, dark scenario presence, light wavelength or bulb type were not consistently reported. We provide a list of standardized metrics for future research and topics that should be explored to expand the current knowledge of ALAN related impacts on bats.
Eastern Small-Footed Bat Ecology at Shenandoah National Park, Virginia
Nicholas J. Kalen; Andrew S. Foy; Paul R. Moosman; Tomás Nocera; W. Mark Ford
The eastern small-footed bat (Myotis leibii) is a small, primarily rock-dwelling species whose ecology and abundance remains poorly understood. Very little information is available describing eastern small-footed bat maternity colonies, and inadequacies of using winter hibernacula counts for estimating their populations leave impacts from white-nose syndrome (WNS) uncertain in many regions, including the Central Appalachians. To better understand eastern small-footed bat abundance and ecology, we conducted visual searches, acoustic surveys, mist-netting, and radio-tracking at talus slopes in Shenandoah National Park, Virginia for use in developing a habitat model and evaluating reproduction. Surveys of 15 talus slopes identified presence of eastern small-footed bats at 13 sites with visual searches and at all 15 using acoustics. From bat observations and random forest regression of remotely sensed data, we produced a predictive model that fit training data (P ≤ 0.001; r2 = 0.79) and offered insights on habitat suitability and talus slope occupancy. We used radio-tracking to document roosts of two productive maternity colonies consisting of at least of 14 and 32 adult females, respectively. Our observations of the larger colony roost network suggest a lower network degree centralization (0.32) compared to most reported of other Myotis spp. Area of this roost network had a minimum convex polygon of 0.50 ha, and females switched roosts every 1.52 ± 0.99 days. Our results suggest that geospatial modeling of visual search observations holds potential for identifying and estimating abundance of eastern small-footed bats on the landscape. Colony findings improve the understanding of eastern small-footed bat maternity colony behavior and habitat requirements in talus slopes. Widespread prevalence of eastern small-footed bats at Shenandoah National Park, as well as observations of successful reproduction suggest, at least locally, the species may be less impacted by WNS than other Myotis spp. in the Central Appalachians.
Effects of Environmental Clutter on Synthesized Bat Echolocation Signals in an Anechoic Chamber
Samuel Freeze
Environmental clutter such as tree boles and foliage affects the recording and identification of bat echolocation calls. Bat detectors are often placed in cluttered areas like forests for research and monitoring purposes, yet automatic identification programs are “trained” on call libraries using passes recorded largely in open spaces. Research indicates that using clutter-recorded calls can increase classification accuracy, but a detailed understanding of how clutter impacts the recording and identification of echolocation calls remains elusive. We experimentally investigated how two measures of clutter, i.e., total basal area and number of stems, as well as recording angle, affected the recording and classification of a synthesized echolocation signal under controlled conditions in an anechoic chamber. Recording angle significantly influenced the probability of correct classification and differed significantly for many of the call parameters investigated. As expected, the probability of recording echo pulses was a function of increased clutter. Overall, an increase in clutter caused enough significant deviations from the synthesized call to cause misclassification in terms of maximum, minimum, and mean frequency and call slope parameters. Results from our work may aid efforts to better understand underlying environmental conditions that produce false positive and negative findings for bat species of interest and how to adjust survey accuracy estimates.

 

Virtual
Location: Virtual Date: Time: -