Browsing by Author "Ford, W. Mark"

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    Acoustic sampling considerations for bats in the post-white-nose syndrome landscape
    Barr, Elaine Lewis (Virginia Tech, 2020-01-27)
    Bat populations across North America are either facing new threats from white-nose syndrome (WNS) and wind energy development or have already experienced precipitous declines. Accordingly, researchers and managers need to know how to best monitor bats to document population and distribution changes, as well as where to look for persisting populations. Landscape-scale WNS impacts to summer bat populations are not well understood, and although acoustic monitoring is commonly used to monitor these populations, there is limited information about differences among acoustic detectors and the implications to managers thereof. My objectives were to model the relationship between WNS impact, influence of available hibernacula, and environmental factors for summer nightly presence of three WNS-affected bats and to compare how multiple models of acoustic detectors perform in terms of detection probability and nightly recorded bat activity. I collected acoustic data from 10 study areas across Virginia, West Virginia, Ohio and Kentucky to describe changes in nightly presence of WNS-affected bat species during summer 2017. During the same period of time, I compared five types of acoustic detectors at Fort Knox, Kentucky. My results show the potential efficacy of using a WNS impact-year metric to predict summer bat presence, and highlight which environmental variables are relevant for large-scale acoustic monitoring. Additionally, my findings suggest that each of the detector types tested would suffice for most research and monitoring activities, but standardization of detector type within the scope of a project or study should be encouraged.
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    Activity patterns and temporal predator avoidance of white-tailed deer (Odocoileus virginianus) during the fawning season
    Higdon, Summer D.; Diggins, Corinne A.; Cherry, Michael J.; Ford, W. Mark (2019-09)
    In the presence of a predator, prey may alter their temporal activity patterns to reduce the risk of an encounter that may induce injury or death. Prey perception of predation risk and antipredator responses may increase in the presence of dependent offspring. We conducted a camera trap study during summer 2015 in North Carolina and Tennessee, USA to evaluate temporal avoidance of a predator (coyote Canis latrans) by white-tailed deer (Odocoileus virginianus). We analyzed activity patterns of bucks, does, and nursery groups (i.e., groups that included fawns) relative to those of coyotes to determine the coefficient of overlap (Delta) using a kernel density estimator. We found that bucks and does had similar Delta with coyotes [Delta(1) = 0.729 (0.629-0.890) and Delta(1) = 0.686 (0.558-0.816, respectively] and exhibited crepuscular activity patterns comparable to those of coyotes. However, nursery groups displayed a dramatically different activity pattern: unimodal activity was concentrated in the middle of the day with little overlap with coyote activity [Delta(1) = 0.362 (0.176-0.491)]. Because adult deer are rarely prey for coyotes, whereas fawns are common prey during summer, the shift in activity patterns of nursery groups demonstrates a behavioral shift likely aimed at avoiding coyote predation on fawns.
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    Activity Patterns of Allegheny Woodrats (Neotoma magister) and Two Potential Competitors in Virginia
    Powers, Karen E.; Thorne, Emily D.; Platt, Logan R.; Anderson, Kayla M. Nelson; Van Meter, Logan M.; Wozniak, Chris M.; Reynolds, Richard J.; Ford, W. Mark (Eagle Hill Institute, 2023-03)
    Neotoma magister (Allegheny Woodrat) is a nocturnal, emergent rock-habitat specialist (i.e., inhabits rocky outcrops, boulderfields, and caves). Woodrat populations have declined range-wide due to habitat fragmentation, endoparasites, and interspecific competition. We estimated the diel activity curves of Allegheny Woodrats and assessed the effects of habitat type (exposed rock habitat/cave- exterior vs. cave-interior) and season (spring, summer, and fall) on curve shape. We also investigated the effect of 2 granivorous competitors' presence and activity curves (Peromyscus spp. and Tamias striatus [Eastern Chipmunk]) on woodrat activity. Additionally, we investigated whether the presence or absence of Procyon lotor (Raccoon), a primary carrier of Baylisascaris procyonis (Raccoon Roundworm), significantly affects the presence or absence of Allegheny Woodrats. We used remote-detecting cameras to document the diel cycles of Allegheny Woodrats and 2 competitors across 83 sites in western Virginia and 2 sites in West Virginia from 2017 to 2022. For 13,002 recorded events, we detected woodrats at 36 of 85 sites (3778 camera events). We observed a higher proportion of daytime activity by woodrats within cave interiors than cave exteriors. Allegheny Woodrat activity curves differed among seasons, with the greatest differences observed between summer and fall and with similar to 80% activity overlap. These activity curves differed significantly when co- occurring with versus not co-occurring with a competitor. Additionally, Allegheny Woodrats showed an inverse activity rate with Peromyscus spp. Thus, our results suggest that competition avoidance via temporal partitioning occurs between these species. Allegheny Woodrats and Raccoons occurred together more often than expected suggesting the presence of woodrats is currently not reduced by the presence of Raccoons. Our remote-detecting camera data help elucidate relationships of Allegheny Woodrats with presumptive competitors, and open avenues for further investigation in Virginia.
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    Activity Patterns of Bats During the Fall and Spring Along Ridgelines in the Central Appalachians
    Muthersbaugh, Michael S.; Ford, W. Mark; Powers, Karen E.; Silvis, Alexander (2019-06)
    Many central Appalachian ridges offer high wind potential, making them attractive to future wind-energy development. Understanding seasonal and hourly activity patterns of migratory bat species may help to reduce fatalities at wind-energy facilities and provide guidance for the development of best management practices for bats. To examine hourly migratory bat activity patterns in the fall and spring in Virginia in an exploratory fashion with a suite of general temporal, environmental, and weather variables, we acoustically monitored bat activity on five ridgelines and side slopes from early September through mid-November 2015 and 2016 and from early March through late April 2016 and 2017. On ridges, bat activity decreased through the autumn sample period, but was more variable through the spring sample period. In autumn, migratory bat activity had largely ceased by mid-November. Activity patterns were species specific in both autumn and spring sample periods. Generally, migratory bat activity was negatively associated with hourly wind speeds but positively associated with ambient temperatures. These data provide further evidence that operational mitigation strategies at wind-energy facilities could help protect migratory bat species in the Appalachians; substantially slowing or locking wind turbine blade spin during periods of low wind speeds, often below where electricity is generated, and warm ambient temperatures may minimize mortality during periods of high bat activity.
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    Activity Patterns of Cave-Dwelling Bat Species during Pre-Hibernation Swarming and Post-Hibernation Emergence in the Central Appalachians
    Muthersbaugh, Michael S.; Ford, W. Mark; Silvis, Alexander; Powers, Karen E. (MDPI, 2019-09-06)
    In North America, bat research efforts largely have focused on summer maternity colonies and winter hibernacula, leaving the immediate pre- and post-hibernation ecology for many species unstudied. Understanding these patterns and processes is critical for addressing potential additive impacts to White-nose Syndrome (WNS)-affected bats, as autumn is a time of vital weight gain and fat resources are largely depleted in early spring in surviving individuals. Our study sought to examine autumn and spring bat activity patterns in the central Appalachian Mountains around three hibernacula to better understand spatio-temporal patterns during staging for hibernation and post-hibernation migration in the post-WNS environment. From early September through November 2015 and 2016, and from early March through April 2016 and 2017, we assessed the effects of distance to hibernacula and ambient conditions on nightly bat activity for Myotis spp. and big brown bats (Eptesicus fuscus) using zero-crossing frequency division bat detectors near cave entrances and 1 km, 2 km, and 3 km distant from caves. Following identification of echolocation calls, we used generalized linear mixed effects models to examine patterns of activity across the landscape over time and relative to weather. Overall bat activity was low at all sample sites during autumn and spring periods except at sites closest to hibernacula. Best-supported models describing bat activity varied, but date and ambient temperatures generally appeared to be major drivers of activity in both seasons. Total activity for all species had largely ceased by mid-November. Spring bat activity was variable across the sampling season, however, some activity was observed as early as mid-March, almost a month earlier than the historically accepted emergence time regionally. Current timing of restrictions on forest management activities that potentially remove day-roosts near hibernacula when bats are active on the landscape may be mismatched with actual spring post-hibernation emergence. Adjustments to the timing of these restrictions during the spring may help to avoid potentially additive negative impacts on WNS-impacted bat species.
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    Assessing the impacts of white-nose syndrome induced mortality on the monitoring of a bat community at Fort Drum Military Installation
    Coleman, Laci Sharee (Virginia Tech, 2013-05-23)
    Since white-nose syndrome (WNS) arrived in the northeastern U.S. in 2006, several affected bat species have exhibited marked population declines (> 90%). For areas such as Fort Drum in northern New York that are subject to regulatory mandates because of the presence of the endangered Indiana bat (Myotis sodalis), acoustic monitoring is now likely more effective than traditional capture methodologies. In the summers of 2011 and 2012, I implemented intensive acoustic sampling using Anabat detectors at Fort Drum to develop a summer acoustic monitoring protocol that is both cost efficient and effective at detecting species of high conservation or management interest, such as the Indiana bat and the little brown bat (Myotis lucifugus). Habitat analysis of radio telemetry data and occupancy models of acoustic data were congruent in confirming nocturnal spatial use of forested riparian zones by little brown bats.  Additionally, occupancy models of passive versus active sampling revealed that passive acoustic sampling is preferable to active sampling for detecting declining species in the post-WNS context. Finally, assessment of detection probabilities at various arrays of acoustic detector layouts in an expected area of use revealed that a grid of detectors covering a wide spatial extent was more effective at detecting Indiana and little brown bats than permanent stations, transects, or double transects. My findings suggest that acoustic monitoring can be affectively implemented for monitoring Indiana and little brown bats even in areas of severe decline. Future efforts should be aimed at determining effective sampling designs for additional declining species.
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    Assessing the Influence of Prescribed Fire on Faunal Communities in a Pyric Landscape
    Jorge, Marcelo Haidar (Virginia Tech, 2020-01-31)
    Understanding the link between environmental factors such as disturbance events, land cover, and soil productivity to spatial variation in animal distributions and vital rates is fundamental to population ecology and wildlife management. The Longleaf pine (Pinus palustris; hereafter, LLP) ecosystem is an archetypal fire-mediated ecosystem, which has seen drastic reductions in land area due to fire suppression. Current restoration utilizes prescribed fire and hardwood removal, but more research is needed to understand the influence of these restoration efforts on the wildlife that exist in that ecosystem. As such, we conducted field surveys on Camp Blanding Joint Training Center and Wildlife Management Area to understand how fire influences relative abundances of mammalian predators, occupancy and species richness of avian species, guilds and communities, and vital rates of white-tailed deer (Odocoileus viginianus) fawns. Our results indicated that mammalian predator space use, and avian species richness were influenced by fire and land cover. Mammalian predator space use was altered by fire conditions and land cover. This mechanism may support predator management strategies that utilizes commonly management techniques for the restoration and conservation of the LLP ecosystem to indirectly alter predator distributions, which has the potential to positively affect the management of important species within this ecosystem. Some mammalian mesocarnivores historically common throughout the southeastern United States were rarely detected, suggesting more research is needed to identify the cause of the potential decline in mesocarnivores in the Southeastern United States. Avian species richness at the community level was positively influenced by the heterogeneity of post fire conditions, or pyrodiversity. Avian species richness of the cavity nesting guild was negatively influenced by increasing time-since-fire. Our results suggest that managers can promote avian community diversity by reducing the size of burn units to create areas with multiple adjacent burn units, with unique fire histories and a mosaic of post-fire conditions. Lastly, fawn recruitment was greater on the higher productivity site than the low productivity site on CB. However, within sites soil productivity did not have a demonstrable effect. In fact, we observed differences between sites, but did not observe any effects of covariates on spatial variation in density or survival of fawns within sites. Although we did not explicitly test the factors influencing our parameters between sites, we hypothesize that the variation in coyote activity rates as well as soil productivity and its subsequent effects (i.e. forage availability, concealment cover, and land cover type) likely drove the differences we saw between sites. These results are relevant to local managers and provide support for unit-specific, deer management on CB. In conclusion, understanding the influence of fire in a frequently burned landscape allows us to better inform management of predators and avian communities using prescribed burns, and the differences in deer populations between areas allowed us to better in inform managers on harvest quotas so that the magnitude of the effect of harvest can better match the population vital rates of each area.
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    Assessing the Long-term Impacts of White-nose Syndrome on Bat Communities Using Acoustic Surveys at Fort Drum Military Installation  
    Nocera, Tomas (Virginia Tech, 2018-06-12)
    With declines in abundance and changing distribution of White-nose Syndrome (WNS)-affected bat species, increased reliance on acoustic monitoring is now the new "normal". As such, the ability to accurately identify individual bat species with acoustic identification programs has become increasingly important. Additionally, how bat distribution and habitat associations have changed at the local to sub-landscape scale in the post WNS environment is important to understand. The significance of these changes, relative to bat activity, may be based on the species-specific susceptibility to WNS. We used data collected from Fort Drum Military Installation, New York from the summers of 2003-2017 to analyze the accuracy of acoustic software programs, and assess the changes in relative bat activity, occupancy, and distribution induced by WNS. Our results indicate that continued acoustic monitoring of bat species, such as the little brown bat (Myotis lucifugus) in the Northeast, to assess ongoing temporal and spatial changes, habitat associations, and as a guide to direct future mist-netting should rely more on relative activity as the metric of choice. Furthermore, the continuous spread of WNS across North America will have strong negative effects on bat populations and communities, this study points to how individual species (both impacted and non-impacted) will respond to WNS. We believe that our results can help users choose automated software and MLE thresholds more appropriate for their needs to accurately address potential changes in communities of bat species due to impacts of WNS or other factors.
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    Assessing the relationships between pollinator-friendly plantings and birds, bats and white-tailed deer on farms in the Coastal Plain of Virginia and Maryland
    Berge, Earle Johnathan (Virginia Tech, 2020-11-30)
    Pollinator-friendly wildflower and native grass plantings are increasingly incentivized by state and federal agencies to improve ecosystem services provided by pollinating insects on farmland. However, the potential ecosystem service benefits, or even disservices, of pollinator-friendly plantings relative to wildlife, such as resident, migratory, and nesting birds (e.g., wild turkey (Meleagris gallopavo)), resident and migratory bats, and white-tailed deer (Odocoileus virginianus) are of interest to both landowners and conservation managers. First, we studied bird species diversity, presence, density, and nesting on farms planted with and without pollinator-friendly plantings to evaluate the potential value of these plantings to bird-related values, such as cultural, recreational, and pest-regulating ecosystem services. Second, we quantified bat relative activity through recorded echolocation calls and explored how relative nightly activity varied across common cover types on a farm, by survey year, and by maternity (May-August) versus non-maternity season (September-April). Third, we determined whether white-tailed deer and wild turkey camera trap success and occupancy differed between farms with and without pollinator-friendly farmscaped plots, evaluated along with their relationships to percent cover of natural, developed, crop, and water habitats within 1 km of surveyed farms. We conducted bird point counts across 20 farms on the Eastern Shore of Virginia and Maryland and the city of Virginia Beach, VA during the Spring and Fall of 2017 and 2018. We searched for bird nests in pollinator-friendly plots during the summers of 2017 and 2018. There were no differences in alpha diversity, defined as the number of species per farm per survey period, between control and pollinator farms in either Spring or Fall. We did find differences in species evenness on farms during Spring surveys, as measured by Simpson's index, with pollinator farms having a higher mean Simpson's index. When examining factors relating to presence/absence of our 15 modeled bird species out of 110 species detected on farms, landscape-level cover types were influential in 14 species and presence of pollinator plots was influential for 5 species. After stratification of density estimates by control and pollinator farm study sites, we found that during Spring surveys, the blue jay (Cyanocitta cristata) and Carolina wren (Thryothorus ludovicianus) had lower density on pollinator farms. In the Fall, the blue grosbeak (Passerina caerulea) had higher density on pollinator farms. We found nesting in the pollinator-friendly plots by red-winged blackbirds (Agelaius phoeniceus; n=7). These nests were placed in locations within the pollinator plots with higher forb coverage than random points in the same plots without nests. We estimated the presence and relative activity of bats in 4 cover types, including forest trail, a forested pond edge, a crop field on forest edge, and a farmscaped wildflower plot, on the Eastern Shore Agricultural Research Extension Center in Painter, Virginia, from April 2017- November 2019 using acoustic detectors. Of total detections, 20.11% were identified as big brown bat (Eptesicus fuscus), 17.97% evening bat (Nycticeius humeralis), 15.35% silver-haired bat (Lasionycteris noctivagans), 7.11% eastern red bats (Lasiurus borealis), 3.66% hoary bats (Lasiurus cinereus), 3.1% little brown bat (Myotis lucifugus), and 1.38% tricolored bat (Perimyotis subflavus). Relative activity measured by calls per night varied by cover type, with relative activity highest for all 7 species in the crop field-forest edge and water-forest edge cover types as compared to pollinator plot and forest trail cover types during the maternity season (May-August). All 7 bat species were recorded in the pollinator plot cover type; of the 8,877 calls in pollinator plots, 26.07% were silver-haired bat, 25.21% eastern red bats, 23.78% evening bat, 9.32% hoary bats, 9.11% little brown bat, 5.42% big brown bat, and 1.09% tricolored bat. We used camera trap surveys to measure white-tailed deer and wild turkey occupancy across 20 farms on the Eastern Shore of Virginia and in the city of Virginia Beach, Virginia during the Spring and Fall of 2017 and 2018. Of all wild species photographed, white-tailed deer were most abundant (TS, # captures/100 nights) each survey season, however this varied season to season (Spring 2017 = 98.44 TS, Fall 2017 = 106.01 TS, Spring 2018 = 80.52 TS, Fall 2018 = 99.71 TS). Wild turkey total survey camera trap success was low compared to deer and other wildlife (4.51 TS), and also varied seasonally (Spring 2017 = 1.73 TS, Fall 2017 = 1.50 TS, Spring 2018 = 7.63 TS, Fall 2018 = 5.95 TS). White-tailed deer were detected at all survey locations at least once, and the occupancy of deer decreased as the percentage of developed land within 1km of a farm increased in each survey season. The factors relating to wild turkey occupancy varied by season. In Spring 2017, wild turkey occupancy increased as the percent of natural cover within 1 km of a farm increased. In Spring 2018, wild turkey occupancy decreased as the percent of developed land within 1 km increased. However, landscape variables did not influence wild turkey occupancy in the Fall seasons; rather in Fall 2018 we found that wild turkey occupancy decreased as camera trap success of farm machinery being used increased. Overall, wild turkey had a fairly low presence on all survey sites with an occupancy ranging from 0.18-0.53%, and no clear relationship to explain the change in survey season to season or year to year. Based on these results, pollinator plot presence or absence was not found to influence detection or occupancy of either of these target game species. Rather, other factors, mainly landscape-scale features, were found to have the largest influence on both species' occupancy and presence. Our study is one of just a few in North America to demonstrate some potential benefits of pollinator-friendly plantings to multiple different wildlife species with cultural, recreational, and insect-regulating ecosystem service benefits to landowners. Generally, birds, bats, and our focal game species' presence relied on surrounding landscape variables and forest-edge configurations more than the presence of pollinator friendly plantings. This is probably in part due to the small size of our pollinator plots. We recommend that future work explore potentially increasing the size of pollinator plot plantings or placing pollinator plantings in locations on the landscape with the most surrounding natural area, and least development, to maximize the benefits of this resource to diverse wildlife species with home ranges that are often larger than any one farm.
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    Assessing the Vulnerability of Military Installations in the Coterminous United States to Potential Biome Shifts Resulting from Rapid Climate Change
    Odom, Richard H.; Ford, W. Mark (2020-10)
    Climate-change impacts to Department of Defense (DoD) installations will challenge military mission and natural resource stewardship efforts by increasing vulnerability to flooding, drought, altered fire regimes, and invasive species. We developed biome classifications based on current climate for the coterminous United States using the Holdridge Life Zone system to assess potential change on DoD lands. We validated classifications using comparisons to existing ecoregional classifications, the distribution of major forest types, and tree species in eastern North America. We projected future life zones for mid- and late-century time periods under three greenhouse gas emission scenarios (low-B1, moderate-A1B, and high-A2) using an ensemble of global climate models. To assess installation vulnerability (n = 529), we analyzed biome shifts using spatial cluster analysis to characterize interregional variation, and identified representative installations for subsequent landscape-level analyses. Although mean annual temperatures are expected to increase, installations located in the Northeast, Lake States, and western Great Plains are likely to experience the largest proportional increases in temperature. Accordingly, forest and grassland communities at these installations managed to support a wide range of training, and environmental objectives may be adversely affected by altered disturbance regimes, heat, and moisture stress. However, precipitation is projected to increase in the Northeast and Lake States mitigating some effects of increased temperatures on biological communities. Given the uncertain response to climate change in different ecoregions, additional environmental and stewardship attributes are needed within a decision-support framework to understand vulnerabilities and provide appropriate responses.
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    Bat activity following repeated prescribed fire in the central Appalachians, USA
    Austin, Lauren V.; Silvis, Alexander; Muthersbaugh, Michael S.; Powers, Karen E.; Ford, W. Mark (2018-12-27)
    Background To restore and manage fire-adapted forest communities in the central Appalachians, USA, land managers are now increasingly prioritizing use of prescribed fire. However, it is unclear how the reintroduction of fire following decades of suppression will affect bat communities, particularly where white-nose syndrome-related population declines of many cave-hibernating bat species have occurred. To address this concern, we monitored and compared bat activity in burned and unburned habitat across a temporal gradient in western Virginia. Results We found evidence for slightly positive fire effects on activity levels of the northern long-eared bat (Myotis septentrionalis [Trouessart, 1897]), Indiana bat (Myotis sodalis [Miller and Allen, 1928]), little brown bat (Myotis lucifugus [Le Conte, 1831]), big brown bat (Eptesicus fuscus [Palisot de Beauvois, 1796])/silver-haired bat (Lasionycteris noctivagans [Le Conte, 1831]) group, all high-frequency bats, and all bat species combined. We observed temporal effects only for the big brown bat, with a negative relationship between activity and time since fire. Conclusions Because response of bat activity was neutral to weakly positive relative to burned forest condition, our results suggest that bats are not a resource that would impede the use of this management tool in the central Appalachians.
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    Bat Activity Following Restoration Prescribed Burning in the Central Appalachian Upland and Riparian Habitats
    Austin, Lauren V.; Silvis, Alexander; Ford, W. Mark; Muthersbaugh, Michael S.; Powers, Karen E. (2018-04)
    After decades of fire suppression in eastern North America, land managers now are prioritizing prescribed fire as a management tool to restore or maintain fire-adapted vegetation communities. However, in long-fire-suppressed landscapes, such as the central and southern Appalachians, it is unknown how bats will respond to prescribed fire in both riparian and upland forest habitats. To address these concerns, we conducted zero-crossing acoustic surveys of bat activity in burned, unburned, riparian, and non-riparian areas in the central Appalachians, Virginia, USA. Burn and riparian variables had model support (Delta AICc < 4) to explain activity of all bat species. Nonetheless, parameter estimates for these conditions were small and confidence intervals overlapped zero for all species, indicating effect sizes were marginal. Our results suggest that bats respond to fire differently between upland and riparian forest habitats, but overall, large landscape-level prescribed fire has a slightly positive to neutral impact on all bats species identified at our study site post-fire application.
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    Bat activity patterns relative to temporal and weather effects in a temperate coastal environment
    Gorman, Katherine M.; Barr, Elaine L.; Ries, Lindsay; Nocera, Tomas; Ford, W. Mark (2021-10)
    The northeastern and mid-Atlantic coasts of the United States are important summer maternity habitat and seasonal migratory corridors for many species of bats. Additionally, the effects of weather on bat activity are relatively unknown beyond coarse nightly scales. Using acoustic detectors, we assessed nightly and hourly activity patterns for eight species of bats over 21 consecutive months at Fire Island National Seashore, New York. The site is an important bat conservation area because it hosts one of the few confirmed northern long-eared bat (Myotis septentrionalis) maternity colonies in the region despite their widespread extirpation due to white-nose syndrome (WNS). There have been no reported captures of little brown bats (M. lucifugus), Indiana bats (M. sodalis), or tri-colored bats (Perimyotis subflavus) at the site post-WNS. Overall, we found mean hourly temperature, time since sunset, day of year, and year to be the most important predictors of bat activity levels for all examined species. Most non-hibernating, migratory species in our study demonstrated a positive relationship to mean temperature at the hourly timescale, whereas cave-hibernating bats tended to show a negative relationship to mean temperature during the time of year when they are expected to be active. Although most bat activity occurred in the late spring through early autumn, peaking in summer, some activity occurred periodically in the winter months, mostly attributable to the big brown bat (Eptesicus fuscus) and silver-haired bat (Lasionycteris noctivigans) phonic group. Unexpectedly, relationships of bat activity to wind and precipitation were largely equivocal. Initial presence (as early as March 30) and departure (between November 1-4) for northern long-eared bats at our study area occurred earlier in the spring and later in the fall than occurs for inland populations, suggesting that the species overwinters on Long Island rather than at inland karst caves or mines. A peak in spring activity characteristic of migratory behavior in the central Appalachians and Atlantic Coast was not observed at Fire Island, although Eastern red bats (Lasiurus borealis) and hoary bats (L. cinereus) - both migratory species - did show a notable rise in activity in the late summer and early fall, suggesting these populations may migrate to and from Fire Island. Understanding the temporal and weather relationships to bat activity in this coastal environment may have important implications for tailoring more effective conservation and management strategies by identifying optimal timing for surveys, tracking bats during peak migratory windows, and providing insights that minimizes impacts to extant bats from activities such as wind-energy development or land management, i.e., forestry.
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    Bat Habitat Ecology Using Remote Acoustical Detectors at the Army National Guard Maneuver Training Center - Fort Pickett, Blackstone, Virginia
    St Germain, Michael J. (Virginia Tech, 2012-04-25)
    Bats occupy diverse and unique niches and are regarded as important components in maintaining ecosystem health. They are major consumers of nocturnal insects, serve as pollinators, seed disperser, and provide important economic benefits as consumers of agricultural and forest pest insects. Bats have been proposed as good indicators of the integrity of natural communities because they integrate a number of resource attributes and may show population declines quickly if a resource attribute is missing. Establishing community- and population-level data, and understanding species interactions is especially important in changing landscapes and for species whose populations levels are threatened by outside factors of anthropomorphic disturbance from hibernacular visitation to energy production and fungal pathogens. For these reasons I have set out to establish habitat use patterns, detection probabilities, spatial and temporal occupancy, and investigate species interactions. This thesis is broken down into three distinct chapters each intended to be a stand-alone document. The first establishes the basic ecology from natural history accounts, provides an overview of the various sampling strategies, and gives a comprehensive description of the study area. The seconds sets out to identify the factors influencing detection probabilities and occupancy of six sympatric bats species and provide insight into habitat use patterns. The third examines spatial and temporal activity patterns and investigates species interactions. This study can provide understanding into the secretive and poorly understood patterns of free flying bats across the landscape. It can also deliver useful information to land managers regarding potential changes in landscape practices for the conservation of bat species.
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    Bat Resource Utilization Along the Potomac River Corridor in Maryland
    Litterer, Amber Starr (Virginia Tech, 2024-04-15)
    In 2021, 17-year periodical cicadas (Magicicada spp.) in Brood X emerged throughout much of the eastern United States. Due to their abundance and lack of predator avoidance during their short six-week period on the above-ground landscape, many species of animals consume cicadas and in turn have short-term habitat use and population responses. The response of bats to periodical cicadas is largely unknown. Using a before-after-control-impact study design, we deployed ultrasonic acoustic detectors during the summers of 2020–2022 within and just outside the range of the cicada emergence along the Potomac River corridor of Maryland and Virginia. For total bat activity, there was significantly more acoustic activity within the range of the cicada emergence the year during and the year following emergence than where emergence did not occur. Additionally, for all individual species and phonic groups, bat activity increased the year during and year after the emergence within the range of periodical cicadas compared to the year prior to emergence. Our study demonstrates that periodical cicadas may serve as a resource pulse that can cause an increase in bat activity and suggests at least a short-term local to regional population increase from immigration the year during and from recruitment the year following. Bats of the mid-Atlantic have been negatively affected by numerous stressors including white-nose syndrome, wind turbine development, and land use change. One species suffering widespread population decline over the last decade in the mid-Atlantic has been the little brown bat (Myotis lucifugus). Understanding the space use and resource selection of remaining populations is critical for management and species recovery. Nevertheless, there are difficulties with studying the movement of insectivorous bats due to their small size and high vagility. Traditional foraging studies of Myotis spp. have used fixed station telemetry and associated multi-azimuthal observations to estimate the location of individuals. However, single azimuth observations are often unable to be included in these studies leading to more potential location estimates missing from movement models. During the summer of 2022, I radio-tagged little brown bats from a maternity colony along the Potomac River in Maryland and collected bearings on nine individuals using fixed station telemetry from sunset until bats returned to the maternity roost. Location estimates were obtained from both single and multi-azimuthal observations. I fit movement models for each individual and used auto-correlated kernel density estimation (AKDE) to estimate space use. I also assessed second and third order habitat selection of individual bats. The average 95% AKDE for males was 889 ha ± 424.6 and 699.3 ha ± 129 for adult females. I found bats had higher predicted use of habitat that was closer in distance to water and wetlands and further from open habitat at the second order and closer to water and open habitat at the third order of resource selection. Habitat associations were similar to previous little brown bat resource selection studies. However, estimates of space use were larger than those using other movement models. This study was novel in that it incorporated single azimuth observations and periodicity into models of space use, thereby increasing sample size and offering a new framework for future telemetry studies. These estimates of space use can be used by land managers to protect the habitat of this imperiled species.
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    A Bear's Eye View: Insight on American Black Bear (Ursus americanus) Hibernation and Foraging Ecology in Virginia's Central Appalachian Mountains
    Holcombe, Brogan Elizabeth (Virginia Tech, 2024-06-07)
    Following mass agricultural expansion and deforestation in the late 1800s and early 1900s, American black bear populations (Ursus americanus, hereafter black bear) were low across most of Virginia. The Department of Wildlife Resources (VADWR) and the United States Forest Service worked to rebuild wildlife habitat in the state, leading to recovery of bears. While some aspects of black bear hibernation and foraging ecology have been studied, there remain knowledge gaps on key aspects of black bear biology. Hibernation behavior, for example, is understudied with most knowledge stemming from post-hibernation emergence studies. We used a unique dataset with continuous monitoring of mother bears and their cubs from Virginia Tech's Black Bear Research Center in 2015-2016, to better understand hibernation ecology, mother-cub dynamics, and biological-foster cub dynamics. We found that increased black bear activity levels were driven by both higher temperature and photoperiod, but the onset of hibernation was primarily driven by only temperature. Temperature is projected to rise in VA and rising temperatures regionally could be responsible for increased active behaviors in bears, which could lead to increased human-black bear interactions on the landscape, especially during hibernation onset. We also found that mother bears spend similar amounts of time with biological and foster cubs. Biological cubs did not show more dominance behaviors toward fosters than biological siblings, which we also observed with foster, where they did not continuously display these behaviors towards biological cubs. These results are promising for orphan cub fostering programs in VA and other states and indicate that foster cub litter integration can be successful. Foraging ecology also is challenging to study in black bears because direct observation is generally not possible due to their cryptic nature, closed habitat, or potential danger in observing. We used a dataset from camera collars deployed on 15 bears (8 males, 7 females) in Bath County Virginia in 2018 and 2019 to better understand diet seasonality and to determine habitat and environmental drivers of black bear foraging patterns, particularly on white-tailed deer (Odocoileus virginianus) and invasive plant species. We identified 178 unique diet items to family, genus, or species in videos, much higher numbers than previously reported in the literature, and we found high diet overlap between sexes. Diet composition was primarily influenced by season with higher levels of consumption of herbaceous soft mast in spring, fruit and seed soft mast in summer, and hard mast in fall. Females exhibited more hunting events on deer fawns in spring than males, but males and females consumed similar numbers (28 vs. 24, respectively) via hunting and scavenging combined. Males consumed anthropogenic foods more often than females, particularly when closer to human settlements and males more commonly consumed invasive plant species in spring while females more often consumed insect in spring invasive species in summer. Our results highlight strong seasonally- and subtle sex-mediated differences in black bear diets. We provide information on drivers of diet choices by bears, as well as identify where foraging hotspots on species of interest occur, providing information useful to VADWR in managing increased human-wildlife interactions (and mitigating potential for negative interactions), predator-prey relations, and invasive species spread across the landscape.
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    Biotic and abiotic mechanisms shaping multi-species interactions
    Maynard, Lauren Danielle (Virginia Tech, 2022-12-20)
    Interactions are important drivers of selection and community structure, which makes the study of multi-species interactions critical for understanding the ecology and evolution of organisms. This dissertation includes four data chapters that examine the biotic and abiotic mechanisms that shape multi-species interactions in both tropical and temperate ecosystems. The first three data chapters (Chapters 2–4) were completed within a Neotropical rainforest in Costa Rica and focus on one plant genus, Piper (Piperaceae). The final data chapter (Chapter 5) was conducted within a working landscape of soybean (Glycine max) fields in eastern Maryland, USA. In Chapter 2, I explore intra- and inter-specific dietary niche partitioning of Piper fruits among three frugivorous bats, illustrating the importance of fine-scale mechanisms that facilitate species coexistence and influence plant–animal interactions. In Chapter 3, I demonstrate how the chemical ecology of a Neotropical shrub, Piper sancti-felicis, shapes fruit interactions with antagonists (fruit fungi) and mutualists (frugivorous bats and birds), developing a foundation for understanding evolutionary ecology of plant chemical traits based on phytochemical investment patterns. In Chapter 4, I describe the direct and indirect impacts of elevated temperature and CO2 concentration on the plant traits and interactions in Piper generalense, improving our understanding of the effects of climate change on a Neotropical plant–herbivore system. In Chapter 5, I explore the biotic (herbivore-induced plant volatiles) and abiotic (fine-scale weather conditions) drivers affecting insectivorous bat foraging in soybean fields in eastern Maryland, providing a pathway to further investigate new strategies for integrated pest management. As a collective work, this dissertation disentangles the nuances of multi-species interactions, exploring foundational mechanisms underlying biodiversity maintenance as well as answering applied questions to address a changing climate and aid sustainable agriculture.
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    Broad-scale geographic and temporal assessment of northern long-eared bat (Myotis septentrionalis) maternity colony-landscape association
    Gorman, Katherine M.; Deeley, Sabrina M.; Barr, Elaine L.; Freeze, Samuel R.; Kalen, Nicholas; Muthersbaugh, Michael S.; Ford, W. Mark (Inter-Research, 2022-02-24)
    As the federally threatened northern long-eared bat Myotis septentrionalis continues to decline due to white-nose syndrome (WNS) impacts, the application of effective conservation measures is needed but often hindered by the lack of ecological data. To date, recommended management practices have been adopted in part from other federally listed sympatric species such as the endangered Indiana bat M. sodalis. During the maternity season, these measures have largely focused on conservation of known day-roost habitat, often with little consideration for foraging habitat, particularly riparian areas. We examined acoustic activity of northern longeared bats relative to day-roost and capture data at coastal and interior sites in the District of Columbia, New York, Pennsylvania, Virginia, and West Virginia, USA, over the course of 6 summers (2015-2020), where maternity activity was still documented after the initial arrival and spread of WNS. Acoustic activity of northern long-eared bats relative to forest cover decreased at the acoustic site level (fine scale) but increased at the sampling region level (coarse scale). We observed a positive association of northern long-eared bat acoustic activity with riparian areas. Additionally, we observed higher levels of activity during pregnancy through early lactation period of the reproductive cycle prior to juvenile volancy. Our findings suggest the need for more explicit inclusion of forested riparian habitats in northern long-eared bat conservation planning. Acoustic sampling in spring and early summer rather than mid- to late summer and in forested riparian areas is the most effective strategy for identifying potential active northern long-eared bat maternity colonies on the local landscape.
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    Browsing Patterns of White-Tailed Deer Following Increased Timber Harvest and a Decline in Population Density
    Crimmins, Shawn M.; Edwards, John W.; Ford, W. Mark; Keyser, Patrick D.; Crum, James M. (Hindawi, 2010-11-02)
    We examined browsing patterns of white-tailed deer (Odocoileus virginianus) on a site in the central Appalachians that experienced a substantial (>50%) reduction in deer population density and an increase in the amount of timber harvest since 2001. We sampled woody browse in and immediately adjacent to 12 clearcuts ranging in age from 0–5 years postharvest in summer 2007. Clearcut-interior areas had higher woody browse abundance and browsing rates than clearcut-edge or mature forest areas. Woody browse abundance was slightly higher within individual clearcuts than in 2001 at higher population densities and lower timber harvest rates. Overall browsing rates declined from approximately 17% in 2001 to less than 5% during our study, suggesting that the combination of deer population control, and increasing the amount of timber harvest across the landscape can reduce herbivory to levels that may not impede growth and survival of forest vegetation.
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    Catawba Sustainability Center and Catawba Hospital Renewable Energy Site Planning Process Study
    Meyers, Ron; Carstensen, Laurence W.; Ford, W. Mark; Grant, Elizabeth J.; Klopfer, Scott D.; Schenk, Todd; Taylor, Adam (Virginia Tech, 2020-09-29)
    The transdisciplinary Renewable Energy Facilities Siting Project produced a white paper outlining their proof-of-concept using a case study from the Catawba Valley.