No description available.

No description available.

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. / Master of Science

The diversity of fish species found in warmwater stream systems provides a perplexing challenge when selecting species for Instream Flow Incremental Methodology (IFIM) studies. An often-suggested approach has been to use habitat guilds to incorporate the diversity found in these systems. My goal is to determine the feasibility of developing habitat suitability criteria (HSC) for the entire fish assemblage in the North and South Fork Shenandoah River, Virginia, using habitat guilds. I examined the strengths and weaknesses of direct underwater observation via snorkeling and throwable anode electrofishing to sample fish habitat use (e.g., depth, velocity, distance to cover, dominant and subdominant substrate, cover, and embeddedness) indicates that using the data collected from both techniques may produce better criteria than using just one of the two sampling techniques. To develop habitat suitability criteria using habitat guilds I placed each species a priori into a guild based on a hypothesized guild structure. Transitional life stages with significantly different habitat use were placed separately into the guild structure. The four guilds (riffle, fast generalist, pool-run, and pool-cover) were found to be significantly different from each other using the data collected for the species assigned to the guilds. Criteria were then developed for representative species from each guild and the entire guilds. Criteria developed for depth, velocity, Froude number, cover, distance to cover, substrate, and embeddedness were used to estimate a habitat response function (i.e., the relations between usable habitat and stream flow) for a representative species from each guild, the guild itself, and for a second species from each guild for comparisons. Both the representative species and guild criteria showed similar habitat response functions for the riffle guild, fast generalist guild, and pool-run guild. However, neither set of criteria performed well for the pool-cover guild. For guilds, other than pool-cover, either the guild or the representative species approach may be a viable option to developing habitat suitability criteria. The transferability tests were performed to determine if criteria developed in the North Fork Shenandoah River, Virginia would transfer to the South Fork Shenandoah River, Virginia. Only criteria for the margined madtom (Noturus insignis) and the juvenile smallmouth bass (Micropterus dolomieu) transferred for both suitable and optimal habitat. Criteria for mottled sculpin (Cottus bairdi), Cyprinella sp. (spotfin and satinfin shiners), river chub (Nocomis micropogon), adult and juvenile redbreast sunfish (Lepomis auritus), and adult smallmouth bass did not transfer. Only the pool-cover guild criteria transferred for both suitable and optimal habitat, while riffle guild, fast generalist guild, and pool-run guild criteria did not transfer. I recommend the use of site-specific criteria for the South Fork Shenandoah or different variable combinations. / Master of Science

No description available.

A abelha Bombus terrestris é um eficiente polinizador, prestando importantes serviços ecossistêmicos na Europa e adjacências, onde é nativa. Suas colônias têm sido criadas em larga escala para polinização agrícola, as quais são comercializadas internacionalmente, inclusive em países fora de sua área de ocorrência nativa. Deliberada ou acidentalmente a espécie tem sido introduzida em ambientes alóctones, em muitos casos tornando-se invasora. Quando invasora, a espécie é um potencial vetor de doenças e um competidor com outras abelhas; vários impactos têm sido relatados em áreas invadidas ao redor do mundo. Na América do Sul, a espécie foi inicialmente introduzida em ambientes naturais no Chile, mas rapidamente a invasão se espalhou; atualmente é encontrada ocupando ambientes naturais na Argentina. A elevada capacidade invasiva da espécie e a alta velocidade de sua expansão, conforme tem sido relatada por pesquisadores, levantou a possibilidade de a espécie alcançar o Brasil por meio de corredores ambientais favoráveis que se conectam com áreas já invadidas, gerando preocupações sobre potenciais impactos aos sistemas naturais e agrícolas. Esta pesquisa empregou uma abordagem interdisciplinar, integrando uma variedade de métodos analíticos oriundos de diferentes áreas da ecologia e os mais avançados recursos de sistemas de informações geográficas para detectar globalmente as áreas susceptíveis à invasão por Bombus terrestris, considerando-se também as mudanças climáticas. Para o sul da América do Sul foram identificados os corredores de invasão que poderão permitir a espécie se espalhar e alcançar Brasil a partir de locais invadidos. Para o Brasil, foram identificados os municípios mais vulneráveis à entrada da espécie, e também aqueles que estão na rota de expansão da invasão Brasil adentro. Para os municípios brasileiros, por sua vez, foram verificadas as culturas agrícolas e as espécies de Bombus nativas que a invasora poderá interagir ao longo da rota de invasão potencial; com estas informações foram apontadas áreas prioritárias, subsidiando o planejamento de monitoramento e ações de controle do processo de invasão, mas também medidas preventivas e mitigadoras de impactos ambientais e econômicos após a invasão, caso venha a ocorrer. / The bee Bombus terrestris is an efficient pollinator, providing important ecosystem services in Europe and surrounding areas, where it is a native species. Their colonies have been reared in large-scale for agricultural pollination, which are internationally traded, including for countries outside its native range. The species has been deliberately or accidentally introduced into non-native environments, becoming invasive in many cases. When invasive, the species is a potential vector of diseases and competes with other bees for resources; many impacts have been reported in invaded countries around the world. In South America, the species was introduced in natural environments of Chile at first, but the invasion was quickly spread; nowadays it is found living in natural environments of Argentina. The high invasiveness of the species and the high speed of its invasive expansion, as has been reported by researchers, raised the possibility of the species reach Brazil through suitable environmental corridors that are connected with areas already invaded, raising the concerns about potential impacts to natural and agricultural systems. An interdisciplinary approach was used in this research, composing a variety of analytical methods from different areas of ecology and applying the most advanced resources of geographic information systems to detect areas susceptible to invasion by Bombus terrestris at global scale, considering also climate change. For the southern South America, the corridors of invasion that could allow the spreading of the species and that potentially reach Brazil were identified. For Brazil, the most susceptible municipalities at the entrance of the species have been identified, and also those that are on the route of expansion inside the country. For Brazilian municipalities, crops and native species of Bombus that the invasive species can interact with along the potential invasion route were verified; with this information, priority areas were identified, supporting the planning of monitoring and control actions of the invasion process, but also preventive and mitigating measures of environmental and economic impacts after the invasion, if it eventually occurs.

Beekeepers in Appalachia market varietal honeys derived from particular species of deciduous trees; however, finding places in a mountainous landscape to locate new beeyards is difficult. Site selection is hindered by the high up-front costs of negotiating access to remote areas with limited knowledge of the available forage. Remotely sensed data and species distribution modeling (SDM) of trees important to beekeepers could aid in locating apiary sites at the landscape scale. The objectives of this study are i) using publicly available forest inventory data, to model the spatial distribution of three native tree species that are important to honey producers in eastern Kentucky: American Basswood, Sourwood and Tulip Poplar, and to assess the accuracy of the models, ii) to incorporate a method for discounting the value of a nectar resource as a function of distance based on an energetic model of honeybee foraging, and iii) to provide an example by ranking potential apiary locations around the perimeter of a mine site in the study area based on their proximity to probable species habitat using a GIS model. Logistic regression models were trained using presence-absence records from 1,059 USFS Forest Inventory and Analysis (FIA) sub-plots distributed throughout a 9,000 km2 portion of the Kentucky River watershed. The models were evaluated by applying them to a separate dataset, 950 forest inventory sub-plots distributed over a 40.5 km2 research forest maintained by the University of Kentucky. Weights derived from an energic model of honeybee foraging were then applied to the probabilities of tree species occurrence predicted by the SDM. As an example, 24 potential apiary locations around the perimeter of a reclaimed mine site were selected and then ranked according to a site suitability index. Three tributary areas corresponding to different honeybee flight ranges were considered: 500m, 700m, and 1,200m. Results confirm that rankings are dependent on the foraging range considered, suggesting that the number of colonies at an apiary location would be an important factor to consider when choosing a site. However, the methodology makes assumptions that are only anecdotally supported, notably i) that colonies will forage preferentially at the target species when it is in bloom and, ii) that foragers will exhaust resources closest to the hive first, regardless of patch size. Additional study of how bees deplete the nectar resources surrounding an apiary is needed to verify the usefulness of SDM in site selection for varietal honey production.

The Louisiana oyster industry is greatly impacted by freshwater and sediment diversions that are part of the effort to restore the state’s coastline. A habitat suitability index (HSI) proposes species-habitat relationships that can be instrumental in creating impact assessments and suitability predictions for management as new diversions are implemented. An oyster (Crassostrea virginica) HSI was developed using three variables crucial to oyster sustainability: average annual salinity, minimum monthly salinity, and average salinity during the spawning season. These Legacy HSI visualizations show annual fluctuations in the distribution of zones suitable for oyster cultivation prior to proposed diversions in Pontchartrain and Barataria Basins from 1967 to 2016. Modeling suitability based upon these variables can provide crucial information for timing the use of diversions to lessen harmful effects upon the oyster industry as well as indicate new potentially suitable areas that the diversions may create.

Large marine vertebrate species can exhibit vast movements, both horizontally and vertically, which challenges our ability to observe their behaviours at extended time-scales. There is a growing need to understand the intra- and inter-annual movements of mobile marine species of conservation concern in order to develop effective management strategies. The basking shark (Cetorhinus maximus) is the world's second largest fish species, however, a comprehensive understanding of this species’ ecology, biology and spatial behaviour in the north-east Atlantic is currently lacking. This thesis seeks to investigate the movement ecology of basking sharks using a suite of technologies to integrate biologging, biotelemetry, remotely sensed data, and ecological modelling techniques. I use satellite telemetry data from basking sharks tracked in 2012, 2013 and 2014 to quantify movements in coastal waters off the west coast of Scotland within the Sea of the Hebrides proposed MPA. Sharks exhibited seasonal residency to the proposed MPA, with three long-term tracked basking sharks demonstrating inter-annual site fidelity, returning to the same coastal waters in the year following tag deployment (Chapter 2). I reveal that sharks tracked into winter months exhibit one of three migration strategies spanning nine geo-political zones and the High Seas, demonstrating the need for multi-national cooperation in the management of this species across its range (Chapter 3). I examine the vertical space-use of basking sharks to improve an understanding of the processes that influence movements in all dimensions. Basking sharks exhibit seasonality in depth-use, conduct deep dives to over 1000 m, and alter their depth-use behaviour in order to remain within thermal niche of between 8 and 16 oC (Chapter 4). Finally, I combine contemporaneous data recorded by deployed satellite tags with remotely sensed environmental data to employ novel ecological modelling techniques to predict suitable habitat for basking sharks throughout the Atlantic Ocean (Chapter 5).

Cape St Francis, Eastern Cape, has been identified as one of four potential sites for establishing a mainland-based African penguin (Spheniscus demersus) colony. This thesis comprises three main components: a verification of a preparation method for stable isotope samples from penguin feathers; a dietary analysis of the penguins on Bird Island, Algoa Bay, though stable isotope analysis of whole blood and feathers (2012 and 2013); and an estimation of available fish surplus that could potentially support a colony of penguins at Cape St Francis. Each component contributes towards the next, all building towards answering the main research question: Will there be enough food around St Francis Bay to support a colony of penguins and sustain the already established fisheries industry within the bay? Stable isotope analysis of whole blood and feathers from breeding adults and whole blood from juveniles provided insight into the variability of African penguins’ diets at different stages in their life history. Stable isotope mixing models indicated that the predicted proportions that each prey species could potentially contribute to diet conflicted with published stomach sample data. This might arise from inaccurate trophic enrichment factors used in the model, or from systematic biases in the published stomach sampling techniques, or both. Dietary sexual dimorphism was not demonstrated by the isotope signatures of breeding penguins. Based on official catch data, the fisheries activity on the south coast, and especially around the potential colony site at St Francis, is much lower than around the west coast’s penguin colonies. The model provided a first-order estimate for fish supply around the potential colony site at St Francis both at a large coastal scale and a local small scale. At both scales the estimate indicated an ample availability of fish at current fishing levels. The model in Chapter 4 can also be applied to refining the assessments of other potential colony sites on the south coast. In conclusion, the south coast is a promising area for a new colony of penguins in terms of food availability. There is relatively low fishing activity in the area and, as suggested by the large-scale model in Chapter 4, an ample fish resource. The final chapter briefly discusses factors that need to be considered before attempting to establish a mainland-based colony of African penguins.