Browsing by Author "Stauffer, Dean F."

Now showing 1 - 20 of 116
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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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    Amphibian Population and Community Characteristics, Habitat Relationships, and First-Year Responses to Clearcutting in a Central Appalachian Industrial Forest
    Williams, Lori Ann (Virginia Tech, 2003-05-08)
    The overall goal of this project was to provide baseline data on amphibian species richness, relative abundance, and habitat use for a long-term landscape ecology study on MeadWestvaco industrial forest in the Allegheny Highlands of West Virginia. From results of area-constrained daytime searches (10 m x 10 m plots) across the landscape, I developed 9 regression models to predict amphibian relative abundance. I constructed models for each year for all plots on all habitat types, plots that were in a Stream Management Zone (SMZ), and plots that were in upland, or non-SMZ, habitat. Distance to perennial or ephemeral streams or perennial ponds (SMZ classification), the amount of available rocks along transects, and site index were the 3 most important habitat variables in models for all plots combined and were responsible for 24-32% of the inherent variation in population relative abundance. Other habitat variables that were significant in models were year, % canopy cover, the amount of available woody debris of decomposition classes 3-5 along transects, % woody stems (<7.5 cm DBH), soil pH, and % herbaceous vegetation. R2PRESS values for all 9 models ranged from 0.08 to 0.35. Amphibian relative abundance showed positive relationships with all significant habitat variables with the exception of year and % woody stems. In natural cover object use/availability analyses, I discovered salamanders preferred rocks over woody debris, relative to the amount available of each. Salamanders preferred flat rocks to any other shape, flagstones to any other type of rock, and rock lengths in the 31-40 cm class. Preferred wood widths were in class 5-10 cm, while preferred wood lengths were in class <50 cm; salamanders exhibited strong preferences for wood in higher states of decomposition (class 3-5). I provided baseline, preharvest data for 28-acre reference areas on 9 forest compartments scheduled for clearcuts. I sampled all 9 reference areas preharvest and sampled 3 during year 1 postharvest using coverboard and night plot surveys. On these 3 areas, species richness declined from preharvest to postharvest, but species diversity showed little change. Overall relative abundance declined significantly preharvest to postharvest with coverboard sampling (p=0.0172) and night plot sampling (p=0.0113). At coverboard stations, relative abundance declined significantly from preharvest to postharvest at a distance of 5-10 m (p=0.0163) and 40-50 m (p=0.0193) away from adjacent mature forest. Finally, using Pianka's index, I compared the night plot and coverboard sampling techniques in terms of proportions of the 4 most common species captured. These sampling techniques on average were >80% similar for all reference areas.
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    Anthropogenic effects on site use and temporal patterns of terrestrial mammals in Harenna Forest, Ethiopia
    Gichuru, Phillys Njambi (Virginia Tech, 2022-03-22)
    There has been little research comprehensively documenting wildlife species in Harenna Forest within the Bale Mountains National Park of Ethiopia. This area is one of the few remaining afro-alpine biodiversity hotspots and is home to numerous endemic plants and animals and offers socio-economic benefits to the neighboring communities. Human population pressure, weak land protection policies, and uncertain land tenure rights have led to increases in farmland for subsistence and coffee farming, livestock grazing, and reduction of afro-alpine, shrubland and grassland habitats. Given these challenges, I used 48 camera trap stations to produce an inventory of wildlife species and to determine factors influencing occupancy (i.e., habitat use), detection, and temporal activity and overlap. I recorded 26 terrestrial and arboreal mammalian species and I had sufficient data to model occupancy for 13 species and temporal activity for 14 species. Occupancy and detection were generally higher for herbivores and omnivores (occupancy: 0.28-0.97; detection: 0.1-0.54) than carnivores (occupancy: 0.31-0.80; detection: 0.04-0.18). I found more evidence of positive anthropogenic impacts on herbivore and omnivore occupancy than negative, while detection was influenced by habitat or landscape features, rather than by humans. Carnivore occupancy was largely unaffected by anthropogenic or habitat variables, but detection was strongly, and mostly positively, influenced by anthropogenic impacts. Temporal activity analyses revealed that, for herbivores and omnivores, only tree hyraxes (Dendrohyrax arboreus) and crested porcupines (Hystrix cristata) were nocturnal, Menelik bushbucks (Tragelaphus scriptus meneliki) were crepuscular, and the remaining species ranged from diurnal to cathemeral. Neither similar body size nor similar diet affected overlap between species pairs. However, overlap with human temporal activity was low for Menelik bushbucks (Δ=0.45) and common duikers (Sylvicapra grimmia) appeared to become less active at stations with high human use. For carnivores, leopards (Panthera pardus) and honey badgers (Mellivora capensis) were crepuscular, and the remaining species were nocturnal. I found evidence that carnivores overlapped less when they were more similar in body size to other carnivores (average Δ=0.67-0.71) compared to species more dissimilar in body size (average Δ=0.75), although there was variation across species. In general, carnivores overlapped much less with humans (average Δ=0.20) than did herbivores (average Δ=0.52) and omnivores (average Δ=0.43). Spotted hyenas (Crocuta crocuta), in particular, appeared to alter activity to reduce overlap with humans. This study provides baseline information on presence, distribution, and activity of large- and medium-sized terrestrial and arboreal mammals in an understudied biodiversity hotspot. My findings are concerning for biodiversity conservation as rare and endangered species (e.g., mountain nyalas (Tragelaphus buxtoni), Ethiopian wolves (Canis simensis)) were rarely or never photographed, and larger carnivores (e.g., lions (Panthera leo), leopards, jackals), generally had low capture rates. The species with higher capture rates, occupancy, and activity tended to be those that can tolerate or take advantage of human activity and disturbance. Species sensitive to human disturbance eventually may be lost unless measures can be put in place to reduce human impacts. This baseline knowledge is important for future studies examining trends in mammalian wildlife populations, such as site extinction and colonization, or changes in overlap with humans, in a landscape that is continuing to experience human-caused, landscape change.
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    Are Road Crossings Fragmenting Populations of Clinch Dace?
    Bourquin, Rebecca M.; Orth, Donald J.; Hallerman, Eric M.; Stauffer, Dean F. (Humboldt Field Research Institute, 2020-11-16)
    Chrosomus sp. cf. saylori (Clinch Dace) is a newly recognized species of minnow with a restricted distribution in southwestern Virginia. We analyzed genetic variation and abundance at paired sites above and below road crossings. Road crossings did not have a strong effect on presence, abundance, or genetic differentiation of Clinch Dace. Of all sites where Clinch Dace were found, only 1 perched culvert presented a barrier to upstream migration; however, no genetic differentiation was found between collections above and below that or any other culvert. Distribution and abundance of Clinch Dace populations were not influenced by habitat variables measured at the site level. Low abundance in small headwaters, nest association, and high mobility appear to be characteristics of this species of Chrosomus.
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    Assessing and evaluating the Forest Stewardship Program: promoting and conducting sound wildlife management
    Hudson, Teresa Michelle (Virginia Tech, 1995-10-05)
    A questionnaire was sent to all U.S. state and territorial Forest Stewardship Program (FSP) Coordinators in 1993 (response rate 90.2%). Despite differences in FSP design and implementation among states, the percentage of available non-industrial private forest (NIPF) acreage enrolled in the FSP (x = 3.4%) did not differ regionally. Professional foresters prepared over 80% of stewardship plans. However, FSP Coordinators perceived that, among all types of preparers, foresters had the greatest need for help in addressing wildlife issues. Most plan preparers had sought help with basic wildlife knowledge and specific, technical management recommendations, but not with field identification, even though site inspections were important in many states. Plan preparers relied on traditional methods (i.e., site inspection) rather than on newer technologies (i.e., computer databases) to inventory important natural/cultural resources. Nationally, landowners requested recommendations for general wildlife improvements more often than either consumptive or non-consumptive wildlife use objectives. Creating and/or managing snags, creating edge, developing food plots, and establishing mast producing species were recommended most often. A second questionnaire was sent to 300 randomly chosen Virginia FSP participants (1991 - 1993) (response rate 81.3%) who declared "wildlife" as their primary or secondary management objective. Respondents reported high satisfaction with Virginia's FSP. Lack of time, money, and equipment, and not knowing where to find skilled help were identified as impediments to implementing recommendations. Work on wildlife recommendations had been initiated by 37 - 69% of landowners.
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    Assessing Habitat Quality for the Endangered Red-cockaded Woodpcker
    Convery, Ken (Virginia Tech, 2002-11-21)
    This project had 2 major objectives. The first objective was to assess how well the revised U.S. Fish and Wildlife Service Foraging Habitat Guidelines depict good quality habitat for the red-cockaded woodpecker (Picoides borealis) at Camp Lejeune, NC. To accomplish this, I used multiple linear and logistic regression to examine the relationships between fitness, habitat use, home range size, and habitat characteristics described in the guidelines. I assumed that habitat characteristics that confer quality were related to higher fitness, greater habitat use, and reduced home range size. To a large extent, the guidelines are validated. Red-cockaded woodpeckers responded favorably to habitat that mimics the historical, mature, and fire-maintained pine forests of the southeastern U.S., characterized by high densities of large pines, low densities of small and medium pines, and a lush herbaceous groundcover. Variables positively associated with habitat use and fitness were associated with reduced home range size, and those negatively associated with habitat use and fitness with increased home range size. Percent herbaceous groundcover was a significant regressor indicative of quality in every model. The second objective was to assess how well USFWS foraging partitions represent habitat used by red-cockaded woodpeckers. I conducted home range follows of 23 groups of red-cockaded woodpeckers and estimated the percentage of each home range encompassed by partitions of varying radii. The percentage of the actual home range included in the partition increased as a function of partition radius. The standard 800 m circular partition, on average, included 91% of the home range, but significant variation existed between groups.
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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 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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    An assessment of Quality Deer Management on a private hunt club in the Virginia Piedmont
    Batts, Gregory K. (Virginia Tech, 2008-02-15)
    I examined the efficacy of Quality Deer Management (QDM) on Amelia Springs hunt club in Amelia County, Virginia, during 2003-2006. I examined home range dynamics of male white-tailed deer (Odocoileus virginianus), deer/hunter interactions, and aspects of population dynamics. I also developed a new rocket net method to capture deer using a remote video system that was more efficient than traditional methods. I monitored 20 deer; 50% died due to hunting and 15% to natural mortality. The emigration rate for juvenile males was 46%, dispersal distance averaged 6.4 km. I used Home Range Extension (HRE) in ArcView to generate annual home ranges (adaptive-kernel) for 16 male deer; I also generated annual and seasonal home ranges using MCP. Annual and seasonal home ranges (MCP) of adult males were larger than those of juveniles. Adult male annual home ranges averaged 2.5 km2 and juveniles 0.9 km2. Seasonal home ranges of adult males were 1.6 km2 and 1.3 km2 during non-hunting and hunting seasons respectively. Juvenile non-hunting and hunting season home ranges were 0.6 km2 and 0.8 km2 respectively. I detected no differences in day/night movements of male deer during the hunting season; however, deer appeared to avoid areas that were hunted based on hunter GPS locations and deer locations during the hunting season. Frequency of deer movement increased during October-November. Population estimates based on remote camera mark-recapture averaged 60 antlered males for the 3-year survey period. Using population reconstruction, the minimum buck:doe ratio was 1:1.8. Estimated density of antlered males was 4.1/km2, in Amelia County, and 5.0/km2 for Amelia Springs. Deer harvested on Amelia Springs, compared to deer harvested on other hunt clubs in Amelia County, were larger. Antler diameters averaged 32.6mm on Amelia Springs versus 26.9mm for other Amelia county hunt clubs, average age at harvest for 2+ males was higher on Amelia Springs (2.4) than other Amelia county hunt clubs (2.2), and dressed body weights averaged 11.2kg heavier (46.2 kg versus 35 kg) on Amelia Springs. QDM on Amelia Springs appears to be successful based on the results. While bigger bucks existed on Amelia Springs, hunters failed to encounter them. Hunters likely would increase buck sightings during the hunting season by becoming more mobile. Expectations of the size of animal (antlers) Amelia Springs can produce should be adjusted to reflect what is possible based on the habitat. The harvest program in place should be continued at the current level for continued success using QDM.
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    An Assessment of the Biological and Socioeconomic Feasibility of Elk Restoration in Virginia
    McClafferty, Julie A. (Virginia Tech, 2000-02-09)
    The biological and socioeconomic feasibility of restoring elk (Cervus elaphus) to Virginia was assessed. Biological feasibility was determined by evaluating habitat suitability for elk while considering potential impacts of elk on existing fauna and flora in Virginia. Suitability was assessed by creating a habitat suitability index (HSI) model that measured the availability and accessibility of open foraging areas and forested cover areas, the availability of permanent water sources, and the degree of fragmentation by roads. Eight areas were identified as potential elk habitat: 1 in Southwest Virginia, 4 in the Shenandoah Mountains (Shenandoah, Highland, Big Meadows, Peaks of Otter), and 3 in the Southern Piedmont (Danville, Brookneal, Rehobeth). The highest potentials for supporting an elk herd were found in the Highland and Big Meadows study areas, medium biological feasibilities were found in the Southwest, Shenandoah, and Brookneal study areas, and low biological feasibilities were found in the Peaks of Otter, Danville, and Rehobeth study areas. A restored elk herd could negatively affect indigenous fauna and flora by changing the structure and diversity of existing forested ecosystems, but impacts can be minimized by maintaining elk populations at or below cultural carrying capacity. The introduction of diseases during restoration and possible transmission of those diseases from elk to humans, livestock, and other wildlife also are concerns, but these issues can be addressed by following a risk minimization protocol. Socioeconomic feasibility was assessed with a statewide mail survey of Virginia residents, 4 regional stakeholder workshops, an analysis of economic costs and benefits associated with elk restoration, and an assessment of the risks of elk-human conflicts in each of the 8 study areas. Overall, most (61%) respondents agreed that elk restoration would be good for Virginia. However, the low response rate (30%) and low confidence among respondents (49%) in their knowledge about elk indicated that most residents do not have the interest and/or necessary information to form a definitive opinion. Residents believe that the greatest benefits of restoration would be the value-based and indirect ecological benefits, such as returning an extirpated species to its native range, whereas the greatest perceived costs were the economic impacts to property, crop depredation, and public safety hazards. In contrast, local stakeholder representatives identified economic returns from increased tourism due to the presence of elk and the creation of new recreational opportunities as the most anticipated benefits; important concerns were the potential for property damage by elk, the potential impacts on local ecosystems, and the costs of implementing and administering an elk restoration program and subsequent elk management. Proposed resolutions for these issues varied by region. Representatives from the Southwest and northern Shenandoah Mountain (Shenandoah and Big Meadows study site) Regions preferred not to restore elk, whereas those from the southern Shenandoah Mountain (Highland and Peaks of Otter study site) and the Southern Piedmont Regions preferred to start out small with a carefully controlled and monitored "experimental" population. Economic benefits of elk restoration, as determined through analysis of data from other eastern states currently managing elk populations, are associated with tourism and the revenues brought to the community during elk hunting seasons, whereas economic costs are associated with crop damage, elk-vehicle collisions, and the administrative costs of managing an elk herd. Although the initial costs of transporting, releasing, and monitoring a founder population likely will exceed immediate benefits, once an elk population is established, benefits likely will exceed costs. However, an equitable distribution of costs and benefits must be devised so that the individuals who bear the costs are afforded a comparable or greater set of benefits. Risk of landowner elk-conflicts was examined by comparing human population densities and growth rates, percent private versus public land, and agricultural trends across the 8 study areas. Highest risk for elk-human conflicts was identified in the Southern Piedmont Region and in the Shenandoah study site, risk was moderate in the Southwest, Big Meadows, and Peaks of Otter study sites, and risk in the Highland study site was low. Overall, the Highland study site had the highest feasibility for elk restoration of all study areas examined; the Big Meadows and Southwest study sites both demonstrated moderate feasibility. Restoration in these areas is possible so long as management objectives remain flexible, plans are made in advance to address potential concerns, and the public is involved in the decision-making processes both before and after elk are released.
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    Avian population and community dynamics in response to vegetation restoration on reclaimed mine lands in southwest Virginia
    Latimer, Chris E. (Virginia Tech, 2012-05-03)
    Coal surface-mining is often implicated for its negative impacts on native flora and fauna. However, some studies suggest that, in reclaiming land after mining, there may be potential to create early successional habitat needed by many avian species currently in decline throughout eastern North America. I evaluated nest-site selection and nest success for on reclaimed mine lands in southwest Virginia during the summers of 2010 and 2011. For this nest-site analysis, I focused on 2 bird species common to reclaimed mine lands in southwest Virginia: field sparrows (Spizella pusillia) and indigo buntings (Passerina cyanea). In addition, I assessed bird community attributes in relation to various surface-mine reclamation regimens over a 5-year period from 2007-2011. For both species, I found estimates of daily nest success to be higher than other estimates reported in the literature; however, empirical estimates of adult and juvenile survival are needed to provide better estimates of population status. For field sparrows, models of avian nest success support the hypothesis that a tradeoff exists between nest concealment and a view of the surroundings for field sparrows. For indigo buntings, year explained the most variation in nest success, with much lower estimates of daily nest survival in 2010, possibly as a result of increased precipitation. I also assessed avian community dynamics in relation to vegetation changes on reclaimed mine sites and observed a total of 96 species throughout the 4 years of sampling. Local species persistence and species turnover were comparable to another continental scale study conducted using breeding bird survey (BBS) data. Observed changes in community vital rates were likely a result of changes in certain habitat attributes over the 5-year period. Lastly, seven species were unique to certain cover types, suggesting the need to consider landscape level processes when developing restoration guidelines for reclaimed coal surface-mines.
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    Bald eagle distribution, abundance, roost use and response to human activity on the northern Chesapeake Bay, Maryland
    Buehler, David A. (Virginia Tech, 1990-01-11)
    I studied bald eagle (Haliaeetus leucocephalus) distribution, abundance, roost use and response to human activity on the northern Chesapeake Bay from 1984-89. The eagle population consisted of Chesapeake breeding eagles, Chesapeake nonbreeding eagles, northern-origin eagles and southern-origin eagles; changes in overall eagle distribution and abundance reflected the net changes in these 4 groups. Breeding territories on the northern Chesapeake increased from 12 to 28 from 1984 to 1988. Breeding eagles were resident all year, always ~7 km from the nest. Chesapeake nonbreeding eagles moved throughout most of the bay, but rarely left it (~5% of the radio-tagged eagles were off the bay during any month). Northern eagles migrated into the bay in late fall (x = 21 December! n = 7! range = 61 days) and departed in early spring (x = 27 March, n = 14, range = 43 days). Southern eagles arrived on the northern bay throughout April-August (x = 6 June, n = 11, range = 94 days) and departed from June - October (x = 3 September, n = 22, range = 119 days). Northern Chesapeake eagle abundance peaked twice annually; in winter (261 eagles, December 1987), driven by the presence of northern eagles, and in summer (604 eagles, August 1988), driven by the presence of southern birds. Of 1,117 radio-tagged eagle locations, only 55 (4.90/0) occurred in human-developed habitat, which composed 27.7% of 1,442 km2 of potential eagle habitat on the northern Chesapeake Bay (P < 0.001). During 36 aerial shoreline surveys, eagles were observed on only 111 of 700 (15.9%) 250-m shoreline segments that had development within 100 m, whereas eagles were observed on 312 of 859 (36.30/0) segments when development was absent (P < 0.001). On average, eagles were observed on 1.0 segment/survey that had coincident pedestrian use within 500 m, compared to 3.6 segments/survey expected if eagles and pedestrians were distributed along the shoreline independently (n = 34 surveys, P < 0.001).
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    Bald eagle habitat use on B. Everett Jordan Lake and Falls Lake, North Carolina
    Chester, Dennis Nathan (Virginia Tech, 1988-06-30)
    I examined the roosting and perching habitat preferences of a nonbreeding population of bald eagles in North Carolina during 1986 and 1987. I characterized roosting habitat at 2 scales; those of forest stands and individual roost trees. Eagles chose roost areas that were less dense, had less canopy cover, were closer to forest edges, and had larger trees than random forest areas (P < 0.05). Within roost areas eagles choose trees that were larger (height and dbh) than random trees. Additionally. eagles roosting at the Morgan Creek roost preferred dead hardwoods close to the forest edge and eagles at the Mason Point roost preferred trees farther from a frequently used dirt road within the roost. Suitable perch trees were the most important attribute of perching habitat. Eagles preferred loblolly pines and trees with leafless crowns (P < 0.05), which relates to their accessible crown structures. Perch trees were larger (height and dbh, P < 0.05) than adjacent trees along the shore. Eagles utilized the bottom of tree crowns during summer but used treetops during fall and winter. I found no evidence that eagles selected perches in relation to forest stand characteristics within 20 m of perch trees, forest cover types in 1 ha blocks surrounding perches, or habitat disturbances. Management recommendations include techniques to enhance bald eagle habitat on the study area. Primary emphasis should be toward managing for roosting habitat because of its apparent scarcity. Perch trees are plentiful but long-term management is desirable. Future nesting seems likely and management techniques for potential nesting habitat are suggested.
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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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    The Biodiversity Mirage: the Effects of Habitat Degradation and Exotic Predators on Ground-Dwelling Forest Birds, Tenrecs and Lemurs in Northeastern Madagascar
    Murphy, Asia J. (Virginia Tech, 2015-06-03)
    Madagascar is one of the world's top conservation priorities due to the intense anthropogenic pressures on its diverse and endemic wildlife. There have been very few studies conducted in the largest protected area complex in Madagascar, the Masoala-Makira landscape (northeastern Madagascar). My goal was to examine the response of ground-dwelling forest birds, tenrecs (Lipotyphla: Tenrecidae) and lemurs to habitat degradation and the presence of exotic predators, and monitor population trends at resurveyed sites from 2008 to 2013. Using camera trap surveys and distance sampling, we observed 26 bird species (n = 4,083 observations), three spiny tenrec species (n = 244 observations) and 12 lemur species (n = 1,172 observations). Out of 13 focal species (seven bird, three tenrec and three lemur species), seven had higher point estimates of occupancy or density at intact forests when compared to intermediately degraded or degraded forest sites. Common tenrecs (Tenrec ecaudatus) and cathemeral lemurs changed their activity patterns, becoming more nocturnal in degraded forests. Feral cat (Felis sp.) trap success was negatively related to the detection of three bird species (red-breasted coua, Coua serriana; scaly ground-roller, Geobiastes squamiger; and Madagascar crested ibis, Lophotibis cristata). At two resurveyed sites (S02 and S05), out of 19 and 17 species, only four and eight species did not show consistent declines in occupancy or encounter rates, respectively, over a six-year period. This research highlights the urgent need for immediate conservation action in the Masoala-Makira protected area complex in order to protect one of the world's biodiversity hotspots.
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    Black bears in Canyon de Chelly National Monument: Life in a changing environment
    Tredick, Catherine Anne (Virginia Tech, 2011-06-23)
    Understanding how wildlife utilize habitat at varying scales is important for understanding and predicting potential impacts of landscape changes (e.g., habitat loss and fragmentation, restoration efforts, climate change, etc.) and in determining effective strategies for conservation and management. This research examines fine-scale and landscape-level habitat use of black bears in Canyon de Chelly National Monument (CACH), Arizona, USA in the context of large-scale landscape change. Currently, CACH is undergoing a large-scale restoration effort to remove all of the non-native Russian olive (Elaeagnus angustifolia) and tamarisk (Tamarix ramosissima and T. chinensis) within the monument. As black bears rely on the Russian olive as a primary food source, a major goal of this research was to evaluate how bears currently use this resource and how its removal might affect bear habitat use and bear-human interactions within the monument. I developed a model of 3rd order (fine-scale) black bear habitat use in CACH using an occupancy modeling approach. Model results indicated that fine-scale habitat selection by bears in CACH is being driven by the presence of non-native Russian olive as well as native food sources. Thus availability of native foods may be sufficient to maintain the bear population in CACH, and bears may quickly adapt to the loss of the non-native food source. Similarly, results showed that bears avoid human areas and farmsteads and prefer higher elevations, suggesting that once olive is removed in the lower canyons near human areas, bear-human interactions may become less of a problem over the long term. I also developed a model of 2nd order (landscape-level) habitat use and evaluated movement patterns of black bears in CACH using location data collected from GPS collars. Model results showed that bears selected areas with higher tree canopy cover and terrain ruggedness, indicating that forest cover and escape cover are primary factors driving black bear habitat selection at the landscape scale in this region. Movement patterns revealed large mean daily movements and low average turning angles, indicating long, linear movements designed to take advantage of the mosaic of available habitats and food resources available over larger areas. I extracted DNA from hair samples collected throughout the study area to examine genetic variability and population structure of black bears in the region. Analyses revealed a relatively healthy, panmictic population across the wider landscape. No substantial genetic structuring was observed in multiple analyses, though I did find evidence of a slight isolation-by-distance pattern within the population. Measures of both current (Nb = 24) and long-term (Ne = 579) effective population size indicated a relatively high number of breeders in the current population and a sufficient amount of gene flow within the larger "superpopulation" to maintain long-term genetic viability. I focused the final portion of my dissertation research on understanding the factors that influence stakeholder acceptance capacity for black bears, which plays a central role in contemporary wildlife management issues, including human-wildlife conflict. I used data from telephone interviews of 1,546 residents in Virginia to develop conceptual models of black bear acceptance capacity at both county and state levels. Model results suggested that more deep-seated and less easily influenced factors (e.g., values and risk perceptions) are at the heart of stakeholder attitudes and perceptions of wildlife, making influencing these perceptions more difficult. Agencies can indirectly affect these attitudes and perceptions, however, by targeting more potentially pliable factors related to wildlife acceptance capacity such as knowledge, personal experience with wildlife, and trust in management agencies.
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    Blood characteristics as predictors of reproductive success in quail species exposed to DDT
    Sullivan, Joseph P. (Virginia Tech, 1991)
    Present sampling techniques are not capable of assessing both contamination with an organochlorine chemical and reproductive success without the need for removing individuals from that population. Experiments were performed to evaluate vitellogenin, vitamin A, and vitamin E as biomarkers of contamination with DDT, an organochlorine pesticide, and reproductive success in Japanese quail (Coturnix coturnix japonica) or northern bobwhites (Colinus virginianus). The utility of vitellogenin as a biomarker in northern bobwhites was investigated. Female northern bobwhites were dosed with 0, 1, 10, or 100 μg DDT/g body weight via corn oil intubation. The females were induced to lay eggs by providing the proper daylength, and number of eggs laid was monitored. No differences were found for number of eggs laid, egg morphology, or plasma concentration of vitellogenin among dose groups. Dietary supplementation and corn oil intubation were evaluated as alternative dosing techniques because handling involved with intubation may have caused decreased egg production in all treatment groups in the first experiment. Nonlaying female bobwhites were dosed with 0 μg DDT, 25 μg DDT/g food, or 25 μg/g body weight (intubation). Bobwhites receiving DDT via intubation accumulated more DDT in brains and livers than did bobwhites receiving DDT via their diet. The two techniques were found not to be equivalent. Vitamins A and E were investigated as biomarkers of DDT contamination and reproductive success in Japanese quail. Female Japanese quail were given 0, 1, 10, or 25 μg dietary DDT. Significant differences were found among dose groups for reproductive success (number of eggs showing embryonic development), and for plasma concentrations of vitamin A. Concentrations of vitamin E were not measurable. Correlation and regression analyses failed to show a relationship between reproduction and vitamin A concentrations. Vitamins A and E also were investigated as biomarkers in northern bobwhites. Female bobwhites were given 0, 1, 10, or 25 ppm dietary DDT. No significant differences were found among dose groups for reproductive success or for concentrations of either vitamin A or vitamin E. Correlation and regression analyses again failed to show any relationship between reproduction and plasma concentrations of vitamins A or E. During each experiment, concentrations of DDT and its metabolites were measured. DDE/DDT ratios in livers, a means of estimating liver enzyme induction, were calculated. The DDE/DDT ratios in livers of Japanese quail and northern bobwhites were found to be markedly different. More work needs to be done to better evaluate the relationship between differences in enzyme induction and reproductive success among different species.
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    Building a Predictive Model of Delmarva Fox Squirrel (Sciurus niger cinereus) Occurrence Using Infrared Photomonitors
    Morris, Charisa Maria (Virginia Tech, 2006-09-11)
    Habitat modeling can assist in managing potentially widespread but poorly known biological resources such as the federally endangered Delmarva fox squirrel (DFS; Sciurus niger cinereus). The ability to predict or identify suitable habitat is a necessary component of this species' recovery. Habitat identification is also an important consideration when evaluating impacts of land development on this species distribution, which is limited to the Delmarva Peninsula. The goal of this study was to build a predictive model of DFS occurrence that can be used towards the effective management of this species. I developed 5 a'priori global models to predict DFS occurrence based on literature review, past models, and professional experience. I used infrared photomonitors to document habitat use of Delmarva fox squirrels at 27 of 86 sites in the southern Maryland portion of the Delmarva Peninsula. All data were collected on the U.S. Fish and Wildlife Service Chesapeake Marshlands National Wildlife Refuge in Dorchester County, Maryland. Preliminary analyses of 27 DFS present (P) and 59 DFS absent (A) sites suggested that DFS use in my study area was significantly (Wilcoxon Mann-Whitney, P < 0.10) correlated with tree stems > 50 cm dbh/ha (Pmean = 16 + 3.8, Amean = 8+ 2.2), tree stems > 40 cm dbh/ha (Pmean = 49 + 8.1, Amean = 33 + 5.5), understory height (Pmean = 11 m + 0.8, Amean = 9 m + 0.5), overstory canopy height (Pmean = 31 m + 0.6, Amean = 28 m + 0.6), percent overstory cover (Pmean = 82 + 3.9, Amean = 73 + 3.1), shrub stems/ha (Pmean = 8068 + 3218, Amean = 11,119 + 2189), and distance from agricultural fields (Pmean = 964 m + 10, Amean = 1308 m + 103). Chi-square analysis indicated a correlation with shrub evenness (observed on 7% of DFS present sites and 21% of DFS absent sites). Using logistic regression and the Information Theoretic approach, I developed 7 model sets (5 a priori and 2 post hoc) to predict the probability of Delmarva fox squirrel habitat use as a function of micro- and macro-habitat characteristics. Of over 200 total model arrays tested, the model that fit the statistical, biological, and pragmatic criteria postulated was a post hoc integrated model: DFS use = percent overstory cover + shrub evenness + overstory canopy height. This model was determined to be the best of its subset (wi = 0.54), had a high percent concordance (>75%), a significant likelihood ratio (P = 0.0015), and the lowest AICc value (98.3) observed. Employing this predictive model of Delmarva fox squirrel occurrence can benefit recovery and consultation processes by facilitating systematic rangewide survey efforts and simplifying site screenings.
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    Characterization of Suitable Habitats for Freshwater Mussels in the Clinch River, Virginia and Tennessee
    Ostby, Brett John Kaste (Virginia Tech, 2005-03-08)
    With a new focus on flow regulation by the Tennessee Valley Authority (TVA) in reservoir tailwaters, it is now possible to recover many mussel species that once occurred in these reaches. Before flows can be modified to create habitat for freshwater mussels, suitable microhabitat conditions must be defined. In this study, I used multiple approaches to define suitable microhabitats for species in the free-flowing upper Clinch River, Virginia and Tennessee, where reproducing mussel populations persist. During summer low flows in 2003 and 2004, I measured flow and substrate conditions in over 1000 microhabitat patches (0.25 m² quadrat samples) across five river reaches. Flow characteristics and embeddedness were significantly different between microhabitats occupied and unoccupied by the most abundant species (MRPP, p < 0.05). Comparison of simple and multiple logistic regression models with Akaike's Information Criteria (AIC) demonstrated that increasing Fleisswasserstammtisch (FST) hemisphere number (a measure of shear stress), decreasing degree of embeddedness, and increasing mean column velocity best explained species occurrences in a microhabitat patch. Subtle differentiation in habitat use among species was observed; however, most species appeared to be microhabitat generalists. Species were grouped into three habitat guilds using corresponding canonical analysis and cluster analysis: fast-flow specialists (FFS), fast-flow generalists (FFG), and slow-flow tolerant (SFT). I used the same data set to develop and test transferability of Habitat Suitability Criteria (HSC) for three habitat guilds and seven species of adult freshwater mussels. Nonparametric tolerance limits were used to define the range of suitable and optimal habitat during summer low flows. Optimal habitat was defined as those ranges of FST hemisphere number, mean column velocity, and embeddedness occupied by the central 50% of independent observations for a species or guild, whereas suitable habitat was defined by those ranges occupied by the central 90% of observations. The transferability of criteria to other reaches of the Clinch River was assessed using one-sided Chi-square tests. Criteria developed for the fast-flow specialist (FFS) and fast-flow generalist (FFG) guilds, as well as most criteria for species in those guilds, transferred to destination reaches. In contrast, criteria developed for the slow-flow tolerant (SFT) guild and individual constituent species consistently failed to transfer. Criteria for FFS and FFG guilds and their constituent species should be incorporated into flow simulation models such as PHABSIM to gauge the effect of minimum flows on mussel habitat quality and quantity. These criteria could also be used to determine suitable sites for mussel translocations. However, my criteria require further testing in other rivers before they can be transferred beyond the Clinch River. Behavior and physiological responses to laboratory manipulations of flow velocity and substrate particle size were used to elucidate microhabitat preferences of Actinonaias pectorosa, Potamilus alatus, and Ptychobranchus subtentum. These species appeared less stressed in the fastest flow treatment, demonstrating significantly higher oxygen consumption and oxygen-to-nitrogen (O:N) ratios than in slower flow treatments. Only P. alatus demonstrated a preference for substrate particle size, and consistently selected finer particle sizes. Actinonaias pectorosa and P. subtentum demonstrated preference for fast-flow microhabitats by readily burrowing in those conditions, while abandoning slow-flow conditions. The lack of preference for substrate particle size demonstrated by A. pectorosa and P. subtentum supports conclusions of previous studies that substrate particle size is of little or secondary importance for explaining mussel microhabitat use. These results, along with previous studies in the Clinch River, demonstrate that the stable habitats of riffles and runs; characterized by fast flows during summer low flows, low percent bedrock, and low embeddedness, are the most suitable habitats for mussel assemblages. To create and maintain suitable habitat conditions in tailwaters, releases should maintain flow over riffles at a minimum depth of no less than 30 cm in riffles that provide higher shear stress conditions (FST number > 7) and velocities (> 0.70 m/s). Periodic releases that are sufficient to transport silt and sand, but not high enough to transport larger substrate should be adequate to maintain substrates with a low degree of embeddedness. Doing so would create suitable habitat for all mussels, from the most to least specialized. Additionally, HSC developed for FFS and FFG guilds can be used to determine suitable destination sites for translocations of species belonging to these guilds.
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    Cheetah of the Serengeti Plains: A home range analysis
    Laver, Peter Norman (Virginia Tech, 2005-11-11)
    Cheetah (Acinonyx jubatus) persist under continued conservation threat in small populations mostly in protected areas in an historically reduced geographic range. Home range, a useful trait for threat assessment, species reintroduction, and population estimation, is plastic in cheetah with sizes ranging from 40 km2 to over 1000 km2 depending on location. Previous home range estimates for cheetah used the minimum convex polygon (MCP), assuming asymptotic home ranges and MCP insensitivity to sample size. They reported metrics of home range size and overlap based on only outline methods. I use 6 481 observations of 240 female and 315 male cheetah from > 60 matrilines over 25 years in the Serengeti Plains to investigate lifetime, core, yearly, and seasonal range size with kernel density estimation. I investigate autocorrelation using time to statistical independence of locations. I confront the assumption of asymptotic home ranges by testing the traditional and multiscaled home range predictions and provide a novel method for determining kernel asymptotes. I challenge the notion of Serengeti cheetah as a migratory carnivore with analyses of site fidelity and objectively defined core ranges. I assess year to year and seasonal location shifts, showing that yearly shifting lessens as females age. I provide quantitative evidence for philopatry in female- and juvenile dispersal in male cheetah of the Serengeti Plains. I use simple overlap metrics to show that overlap in lifetime and core ranges is greater in related than unrelated female pairs. I use multi-response permutation procedures (MRPP) to show that overlap in unrelated female pairs varies with season. I use correlation of utilization distributions to show that avoidance is apparent only in unrelated pairs of females. My results call into question previous MCP estimates of cheetah home range size, and provide guidance for future sampling of cheetah locations. My home range results will guide management of this imperiled species and my methodological findings may be general and applicable to a wide range of taxa.