Browsing by Subject "species distribution model"

Now showing 1 - 4 of 4
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    An Evaluation of Black Sea Bass (Centropristis striata) Distribution and Habitat Availability in the Northwest Atlantic Ocean under Climate Change
    (2021-04-30) Franco, Crystal
    Fishery scientists are increasingly concerned about the impacts of climate change on marine fisheries and ecosystem health. Many marine species along the Northeast United States continental shelf have shifted spatial distribution and abundance in response to local climate variability and large-scale warming. Such shifts over time can influence management decisions to adjust commercial and recreational allocation along the eastern seaboard, as demonstrated in recent state allocation changes for Black Sea Bass (Centropristis striata). This master’s project evaluates black sea bass fishery-independent survey and fishery-dependent landings data (1986-2019) using a two-stage generalized additive model to identify the importance of environmental factors in shaping their spatial abundance and project future distribution shifts under a “business as usual” climate change scenario in which future carbon emissions are consistent with the current pace of global emissions. This approach may provide insight into future suitable habitat availability of black sea bass, and this master’s project serves to contextualize the need for adaptive management that increases the equitable and economically sound distribution of access to marine resources in a changing climate.
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    Assessing the current and future status of aquatic and hydrologic ecosystem services in the French Broad River Basin
    (2017-04-28) Thompson, Brenna; Shapiro, Hannah; Warnell, Katie
    Ecosystem services are the benefits that people receive from nature, and are an increasingly important component in conservation planning. Many of these ecosystem services are threatened, however, by land use change and development, climate change, and pollution. This project assesses the current state of several water-related ecosystem services in western North Carolina’s French Broad River Basin, which includes the city of Asheville, and compares this to a potential future state given predicted changes in development patterns and climate. We identify where sources of water-related ecosystem services are located within the watershed, how many people they serve, where threats to ecosystem services are located, and how ecosystem services and aquatic biodiversity may be affected by future climate and land use changes. Our findings show that climate change and development will have significant implications for the future provisioning and regulation of ecosystem services and the habitat of aquatic biodiversity in western North Carolina.
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    Brown Hyena (Hyaena brunnea) Distribution: Nuances in Modeling a Generalist Species
    (2020-04-24) Killea, Allison
    The brown hyena plays a critical role as a top carnivore across southern Africa alongside other megafauna including lions and cheetahs. However, because it is perceived to face fewer threats to its population, there are fewer research efforts aimed at understanding its distribution and spatial ecology. The Hyaena Distribution Mapping Project in partnership with the IUCN Hyaena Specialist Group is currently working to update the global range map of the brown hyena. A critical follow up to this work is the creation of a species distribution model to better understand the environmental factors that affect their spatial ecology. However, given the wide variation of habitat types within the hyena’s range, a single model may not be sufficient to capture the nuances within their global distribution. I created a global model of the brown hyena as well as two biome specific models, one for Deserts and Xeric Shrublands and one for Tropical and Subtropical Grasslands, Savannas, and Shrublands as defined by the World Wildlife Fund. I propose that brown hyena ecology varies based on the specific ecosystem of an individual and that by modeling their distribution at a biome level we can better predict potential habitat. However, a general model may still be informative as hyenas do range widely, and one individual can take advantage of a variety of habitats. By comparing these models and their performance, we can create a more robust description of how brown hyena ecology varies throughout southern Africa.
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    Viability and improvement of constructive wildlife corridors in tropical forests, proposing a new method for evaluating corridors geospatially using MaxEnt
    (2022-12-14) Markus, Caitlin
    Habitat corridor ecology remains a new and developing field in wildlife and forest management. Little is known about how corridors statistically work or how they should be established and monitored. Stuart Pimm and his non-profit Saving Nature build constructive habitat corridors in tropical forests, and he now hopes that the data collected from these corridors can contribute to the growing knowledge in this field. In this study, I analyzed camera trap data from Saving Nature’s corridors in Colombia, Ecuador, and Brazil. Occupancy models were run to determine general corridor efficiency based on the species detected in the camera traps and species that were expected to appear based on environmental variables. I also attempted to propose maximum entropy models as an alternative way to achieve the same goal. Finally, least cost path corridor models were run to identify the areas animals are most likely to be found in, so that cameras can be repositioned to collect more data. Overall, all corridors were determined to be working adequately, but with room for improvement. MaxEntmodels show some potential as a method to evaluate corridor projects, but model refining and further research and development are required.