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Compression wood formation in Pinus strobus L. following ice storm damage in southwestern VirginiaHook, Benjamin Austin 21 May 2010 (has links)
To evaluate the compression wood response in eastern white pine (Pinus strobus L.) following a severe ice storm in 1994, 47 trees were felled in 2007 and cross-sectional samples were collected at 0.5 (±0.2) m stem height. The disks were sanded and digitally scanned, and the cross-sectional area (mm2) of compression wood within each tree-ring was quantified using image analysis software. Topographic data (slope, aspect, and elevation) were also recorded for each P. strobus tree, along with a modified competition index. Wood anatomical features were also quantified in the three years before and after the storm along a tree diameter gradient. Although tree age was relatively constant in this stand, tree size was influenced by topographic position; larger trees grew in the valley while smaller trees were found growing in thin soils at the mid-slope position. When the cohort was about 25 years old, ice deposition caused a heterogeneous compression wood response which was highly related to tree size. In the thirteen years following the ice storm, the 6 – 9 cm (2007) diameter class formed significantly more compression wood area than any other, followed by the 10 – 13 cm (2007) diameter class. The tree diameter range that formed the most post-storm compression wood was 4 – 8 cm at the time of the storm, suggesting that this diameter range was most affected by 8.5 cm of ice loading in P. strobus. Trees > 18 cm in 1994 did not form any compression wood after the storm, but many experienced a growth release to fill canopy gaps. Topographic variables did not influence compression wood formation directly, but only one plot was sampled so these results are tenuous. However, topography did influence tree size which was the most important predictor in compression wood. There was no relationship between compression wood area and competition index. Due to compression wood formation after the ice storm, cell wall thickness and cell circularity were significantly higher in the 1994 tree-ring than in other rings examined (1991 – 1993, 1995, and 1996). Tracheid and lumen diameters were significantly smaller in compression wood cells (30.5 and 19.5 μm, respectively) than in normal wood (36.8 and 28.4 μm, respectively); opposite wood cells were intermediate in size (32.4 and 24.4 μm, respectively). Due to small tracheid size, compression wood contained significantly more cells mm⁻¹ (33) than normal wood (27), but no significant differences in cell wall area. Therefore, cumulative cell wall area occupied 47% of the cross-section in compression wood tissue on average, compared to 31% in normal wood. Dispersing tree weight across a greater surface area may help compression wood to prop up a bent tree, but reduced lumen area may also impact hydraulic conductivity in the stem. / Master of Science
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Spatial Ecology of Bobcats (Lynx rufus) in the Appalachian Mountains of Western VirginiaMcNitt, David C. 27 August 2019 (has links)
Despite the prevalent distribution of bobcats in western Virginia and the broader region of Appalachia, there is a paucity of information on their spatial ecology in this region. Due to the unique ecological conditions of Appalachia, and increasing public interest surrounding the role of bobcats as predators in the region, there is a need for local information on bobcat ecology. I utilized data from 20 GPS collared bobcats (14M, 6F) to investigate bobcat spatial ecology in the mountains of Western Virginia. Average resident male home range size was 33.9 ± 2.6 km^2, nearly 3 times larger than average resident female home range size (12.1 ± 2.4 km^2). Seasonal areas of use did not differ in size among seasons, but exhibited minor shifts in location and shape. Average male movement rates (232.3 ± 12.0 meters/hour) were 1.5 times greater than average female movement rates (154.4 ± 8.9 meters/hour). Male movement rates increased during the dispersal season and female movement rates increased during the denning/kitten-rearing season. Second order resource selection analysis indicates that bobcats of both sexes select home ranges at higher elevations than expected at random, and that selection varies between sexes and among seasons. Third order resource selection analysis indicates that bobcats select for locations near open canopy structure, and avoid forest interior. These findings build upon previous findings regarding bobcat diet and population dynamics to provide a comprehensive understanding of basic bobcat ecology in western Virginia, and will inform further research investigating predator/prey interactions. / Master of Science / Despite the prevalent distribution of bobcats in western Virginia and the broader region of Appalachia, there is a paucity of information on their spatial ecology in this region. Due to the unique ecological conditions of Appalachia, and increasing public interest surrounding the role of bobcats as predators in the region, there is a need for local information on bobcat ecology. I utilized data from 20 GPS collared bobcats (14M, 6F) to investigate bobcat spatial ecology in the mountains of Western Virginia. I found that male bobcats use more space than females, with home ranges nearly 3 times larger and movement rates 1.5 times higher. I found that home ranges do not expand or contract throughout the year, but do shift in shape slightly. I found that bobcats select home ranges at higher elevations, indicating that home ranges are predominantly located on ridges. I found that selection of home ranges differed between sexes and seasons, indicating that shifts in home range shape throughout the year reflect varying habitat selection. Within their home ranges, I found that bobcats select for areas of open canopy resulting from fields, fire, and timber harvest; and avoid areas of forest interior. These findings build upon previous findings regarding bobcat diet and population dynamics to provide a comprehensive understanding of basic bobcat ecology in western Virginia, and will inform further research investigating predator/prey interactions.
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Landscape Influences on Spatial Patterns of White-tailed Deer Herbivory and Condition Indices in the Central Appalachian MountainsKniowski, Andrew Broni 08 December 2016 (has links)
White-tailed deer (Odocoileus virginianus) are a common and important game species throughout much of the central Appalachian region. The central Appalachian region encompasses a wide variety of habitat conditions and spatial habitat arrangements that may influence deer populations and management as well as deer impacts to ecosystems. Locally to regionally, deer populations have had an increasingly negative effect on forest biodiversity and a growing influence on forest succession. In Virginia, the combination of these factors has prompted establishment of deer population management goals and policies designed to support conservation of biodiversity, forest regeneration, and continued hunting opportunities. However, limited information is available to inform broad-scale assessment of herbivory impacts. Likewise, lack of understanding about the spatial variability of herbivory across and among landscapes impedes consistent application of ecological measures under differing management scenarios and landscape conditions. I evaluated deer herbivory intensity, the predictability of browsing rates, and the relationships and possible interactions between deer body mass and potential food sources, winter severity, and deer population density in the central Appalachian Mountains of Virginia. My results provide support for the inclusion of spatial factors to help partition variation of deer herbivory to allow for improved precision and accuracy in the design of field herbivory impact assessment methods and improve their application across various landscape contexts. Also, effective broad-scale herbivory impact assessment should include spatially-balanced vegetation monitoring that accounts for regional differences in deer forage preference. Agriculture and other non-forest habitats may provide resources that result in larger deer body mass either directly through food items or indirectly through alteration of the remaining forest habitat such as through increased edge. This suggests that available food sources and habitat are related to deer physiological parameters in the central Appalachian region and vary across landscapes. Likewise, these factors can change or can be affected through management across time. As a result, spatial approaches for monitoring and analysis are required for effective management and understanding of deer populations and herbivory impacts to biodiversity. / Ph. D.
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Fire Regimes of the Southern Appalachian Mountains: Temporal and Spatial Variability and Implications for Vegetation DynamicsFlatley, William 1977- 14 March 2013 (has links)
Ecologists continue to debate the role of fire in forests of the southern Appalachian Mountains. How does climate influence fire in these humid, temperate forests? Did fire regimes change during the transition from Native American settlement to Euro-American settlement? Are fire regime changes resulting in broad vegetation changes in the forests of eastern North America? I used several approaches to address these questions.
First, I used digitized fire perimeter maps from Great Smoky Mountains National Park and Shenandoah National Park for 1930-2009 to characterize spatial and temporal patterns of wildfire by aspect, elevation, and landform. Results demonstrate that fuel moisture is a primary control, with fire occurring most frequently during dry years, in dry regions, and at dry topographic positions. Climate also modifies topographic control, with weaker topographic patterns under drier conditions.
Second, I used dendroecological methods to reconstruct historical fire frequency in yellow pine (Pinus, subgenus Diploxylon Koehne) stands at three field sites in the southern Appalachian Mountains. The fire history reconstructions extend from 1700 to
2009, with composite fire return intervals ranging from 2-4 years prior to the fire protection period. The two longest reconstructions record frequent fire during periods of Native American land use. Except for the recent fire protection period, temporal changes in land use did not have a significant impact on fire frequency and there was little discernible influence of climate on past fire occurrence.
Third, I sampled vegetation composition in four different stand types along a topographic moisture gradient, including mesic cove, sub-mesic white pine (Pinus strobus L.) hardwood, sub-xeric oak (Quercus L.), and xeric pine forests in an unlogged watershed with a reconstructed fire history. Stand age structures demonstrate changes in establishment following fire exclusion in xeric pine stands, sub-xeric oak stands, and sub-mesic white pine-hardwood stands. Fire-tolerant yellow pines and oaks are being replaced by shade-tolerant, fire sensitive species such as red maple (Acer rubrum L.) and hemlock (Tsuga canadensis L. Carr.). Classification analysis and ordination of species composition in different age classes suggest a trend of successional convergence in the absence of fire with a shift from four to two forest communities.
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A Case Study of Civil War Environmental and Medical History Through the Disease Seasoning of the 58th North Carolina Infantry Regiment in East TennesseeRichard, Ashlie 01 August 2020 (has links)
This thesis is a case study aimed at a key argument in the emerging field of Civil War medical and environmental history. While historians have long acknowledged disease as a major killer during the Civil War, only recently have environmental and medical historians turned their collective attentions to unpacking the complex interconnections of disease, environmental conditions, and culture. By examining the 58th North Carolina Infantry Regiment from the mountains of western North Carolina, this thesis asserts that the combined role of the disease environment and conditions in military camps created the massive outbreaks of disease that characterized the seasoning process of the regiment. Furthermore, the soldiers were practical in their response to conditions, weighing family, nation, and other factors in the face of death. When the threat of disease combined with personal and other factors, many soldiers deserted or took other actions of self-preservation over loyalty to the Confederacy.
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Population Dynamics and Spatial Ecology of White-tailed Deer in the Central Appalachian Mountains of VirginiaClevinger, Garrett Balee 17 November 2022 (has links)
White-tailed deer (Odocoileus virginianus) are a highly charismatic game species with considerable ecological and economic impacts across most of their range. In the Central Appalachian Mountains, deer are a keystone species in forested ecosystems. Regionally, populations vary in herd growth or decline. These fluctuations are important in that they often drive many aspects of population management and regulation, which are dependent on herd demographics. Some key population vital rates allowing better understanding of these changes in white-tailed deer herds are survival, cause-specific mortality, home-range variation, both broad and fine-scale resource selection, and ultimately population growth trends in response to changes in both population vital rates and hunter harvest regulations. In this study, I address each of these concepts within a deer population in Bath County, Virginia, that has presumably been in overall decline since the early 1990's. From June-September, 2019-2020, I monitored survival and cause specific mortality of 57 neonate white-tailed deer until 12 weeks of age. Fawn and adult female survival was 0.310 (95% CI = 0.210-0.475) and 0.871 (95%CI=0.790-0.961) respectively. During the study, I observed a total of 37 fawn mortalities and identified the cause of death using field evidence and through analyzing genetics from residual predator salvia recovered on deer carcasses. Mortalities included 28 predation events and 9 deaths from other causes (e.g., abandonment, malnutrition, or disease). Black bears accounted for 48.6% of all mortality and 64.2% of known predations within our study. My top model identified elevation as a significant predictor of fawn survival, with mortality risk increasing 20% for every 100m increase in elevation. My model using observed vital rates predicted an increasing population of λ = 1.10 (interquartile range, IQR 1.06-1.14). The population was predicted to increase by 2% with a 10% increase in doe harvest (λ = 1.02, IQR = 0.97-1.06) but declined by 7% at 20% harvest (λ = 0.93, IQR = 0.89-0.96). I found that fawning home ranges of females that successfully reared fawns to the end of the season had significantly larger home ranges than those that were unsuccessful at higher elevations. Fawning home ranges for females with fawns increased approximately 71ha in size for every 100m increase in mean home range elevation, whereas seasonal home ranges of females without fawns decreased approximately 1.5 ha for every 100m increase in mean home range elevation. Deer selected fawn-rearing areas nearer to forested edges, open habitats, and at higher elevations, while they avoided areas near disturbed and mature forests. Within the fawn rearing area, females selected locations closer to disturbed forest, open habitats, and forested edge, while avoiding mature forest habitats, and higher elevations. Females selected birth sites with higher levels of visual obstruction. Using a step-selection method for real-time resource selection across biological seasons, we found that female deer selected for open areas during the fawning, breeding, early gestational, and late gestational seasons. During the fall breeding season, females avoided forested edge, but selected for areas at higher elevations. During early gestational seasons females selected disturbed habitats and areas at higher elevations while again avoiding forested edge. Overall, my work highlights variations in population dynamics of white-tailed deer in areas of the Central Appalachian Mountains that are primarily characterized by poor habitat quality and provides novel insights into fine-scale spatial ecology of female deer across biological seasons within the region. Ultimately, while the deer population in our study was not predicted to be in decline, this work supports predation risk as being a significant factor associated with habitat quality. / Doctor of Philosophy / White-tailed deer (Odocoileus virginianus) are a game species with extensive ecological and economic impacts across most of their range. In the central Appalachian Mountains, many populations across the region vary in terms of herd size growth, stability, or decline. These fluctuations are important in that they often drive many aspects of population management and regulation, which are dependent on the status of herd demographics. Some key population vital rates that aid us in better understanding these changes in white-tailed deer herds are survival and cause-specific mortality, home-range variation in association with habitat quality and the ability to successfully reproduce, population trends under hypothetical management scenarios, and resource selection of various habitats that are available across the landscape. In this study, I address each of these concepts within a deer population in Bath County, Virginia, which has presumably been in decline since the early 1990's. As expected, fawn survival was lower than previously reported from other study areas of the Central Appalachians Mountains. Predation was the leading cause of fawn mortality, with black bears being responsible for most predation events. Fawn mortality risk was significantly associated with elevation - where fawns at higher elevations were those at greater risk. Surprisingly, the deer population in Bath County was projected to be increasing under current conditions and was also projected to be stable-to-increasing even under some hypothetical scenarios which would negatively impact population growth (i.e., 10% increase in female harvest or 17% reduction in fawn survival). Fawning home ranges of collared females which successfully reared known fawns to the end of the biological season were significantly influenced by elevation; such that females with fawns had home ranges that increased in size with increasing elevation, whereas females without fawns had home ranges which decreased slightly in size with increasing elevation. At birth sites, females selected locations characterized by higher levels of visual obstruction compared to randomly sampled areas. Of the habitat types analyzed, both selection or avoidance of specific habitats varied across both biological season and spatial scale. Ultimately, while I found that some deer populations associated with poor quality habitats in the Central Appalachians may not be in decline, deer were likely influenced greatly by habitat quality – especially pertaining to predation risk – throughout Bath County.
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Factors Affecting White-tailed Deer Recruitment in VirginiaAubin, Gisele Rosalie 12 June 2020 (has links)
Deer (<i> Odocoileus </i> spp.) are an important cultural and economic resource. They are the most popular game species in the United States and the number one driver of conservation funding. On the other hand, they also cause damage to resources including to the agricultural industry, private property and to humans via deer vehicle collisions. Many areas in eastern North America have experienced a decline in white-tailed deer (<i> Odocoileus virginianus </i>) populations over the past twenty years concurrent with changes in landscape, deer harvest strategies, and increasing and expanding black bear (<i> Ursus americanus </i>) and coyote (<i> Canis latrans </i>) populations. Most studies have addressed this problem at small spatial and temporal scales and in areas where predation was assumed to be limiting population growth. We evaluated white-tailed deer fawn recruitment both directly and indirectly at relatively broader spatial and temporal scales. We studied fawn survival on Marine Corps Base Quantico in Virginia, USA from 2008–2019. We used the Kaplan-Meier estimator, and Cox-proportional hazards models to assess annual survival and factors that influence hazard risk such as sex, weather, landscape composition and configuration and food availability. On Marine Corps Base Quantico, we found an increase in red oak mast abundance increases survival and probability of fawn survival was higher during the first interval of the study (2008–2010; 0.71 [0.52–0.96]; survival probability [CI95%]) than the last three intervals (2011–2013; 0.46 [0.30–0.70]; 2014–2016; 0.48 [0.35–0.66] and 2017–2019; 0.50 [0.39–0.63]). We also found that predation was the leading source of mortality. We assessed recruitment using lactation status from hunter harvest data collected by the Virginia Department of Game and Inland Fisheries during a 22-year period in 30 counties in the Appalachian Mountains of western Virginia. We predicted lactation status as a function of landscape composition and configuration, oak mast abundance, weather, age, and predator detection rates using generalized linear mixed models. We found land cover diversity index positively and black bear detection rate negatively influenced recruitment. Age also predicted lactation status with middle-aged females (3.5–4.5 years old) having a higher lactation probability than mature (≥5.5 years old) age and young (2.5 years old) age class deer. Based on these findings, recruitment is likely to be greater in areas that are heterogeneous. Therefore, if an increase in recruitment is desired silvicultural practices such as fire and timber harvest could be used to permanently change land cover types. These silvicultural practices could also be used to increase the number of oaks on the landscape, and augment production of mature oaks as red oak mast abundance influenced fawn survival. Also reducing predation by manipulating predator densities could improve recruitment. Another potential option which needs further research, would be to reduce predator efficiency by increasing hiding cover for fawns. / Master of Science / Deer (<i> Odocoileus </i> spp.) are an important cultural and economic resource. They are the most popular game species in the United States and the number one driver of conservation funding. Conversely, they also cause damage to resources including to the agricultural industry, private property and to humans via deer vehicle collisions. Some areas in eastern North America have experienced a decline in white-tailed deer (<i> Odocoileus virginianus </i>) populations over the past twenty years concurrent with the colonization of coyotes (<i> Canis latrans </i>) as well as changes in habitat. Therefore, we aimed to determine white-tailed deer fawn survival rates and factors affecting recruitment across a large spatial and temporal scale. Recruitment is when an individual becomes part of the reproductive population. However, for harvestable populations, recruitment is when individuals can be legally harvested for the first time. On Marine Corps Base Quantico from 2008–2019, in Virginia, USA we found that probability of fawn survival was higher during the first interval of the study (2008–2010; 0.71 [0.52–0.96]; survival probability [CI95%]) than the last three intervals (2011–2013; 0.46 [0.30–0.70]; 2014–2016; 0.48 [0.35–0.66] and 2017–2019; 0.50 [0.39–0.63]). We also discovered predation was the leading cause of death and probability of survival increased with increasing red oak mast abundance. Over a large spatial (30 counties) and temporal (22 years) scale we examined fawn recruitment by predicting lactation status of female harvested white-tailed deer in the Appalachians Mountains of western Virginia. We found land cover diversity index positively and black bear (<i> Ursus americanus </i>) detection rate negatively influenced recruitment. Age also predicted lactation status with middle-aged females (3.5–4.5 years old) having a higher lactation probability than mature (≥5.5 years old) age and young (2.5 years old) age class deer. Based on these findings, recruitment is likely to be greater in areas that have a mixture of land cover types. Therefore, if an increase in recruitment is desired silvicultural practices such as fire and timber harvest could be used to permanently change land cover types. These silvicultural practices could also be used to increase the number of oaks on the landscape, and augment production of mature oaks as red oak mast abundance influenced fawn survival. Also reducing predation by manipulating predator densities could improve recruitment. Overall, we found diversity of land cover types, food availability, predators, and age influences population dynamics of white-tailed deer.
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