Department of Geography

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Browsing Department of Geography by Subject "Biology"

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    The impact of storm surge from successive hurricanes on the Alabama beach mouse population
    (University of Alabama Libraries, 2011) Yuro, Alexandra Marie; Steinberg, Michael; University of Alabama Tuscaloosa
    Global environmental change affects plants and animals by changing their distributions and phenology, and altering ecosystem functions. Already endangered plants and animals subject to these changes may be more vulnerable to extinction. It is important to understand how species are likely to respond to environment change so that proper steps can be taken to protect them in the future. This thesis observes the case of the Alabama beach mouse (Peromyscus polionotus ammobates), a population endangered initially because of habitat loss and fragmentation. The Alabama beach mouse population likely will be negatively affected by environmental change through increased hurricane frequency and intensity. Using Alabama beach mouse trapping data provided by the U.S. Fish and Wildlife Service, I examined the storm surge effects of Hurricanes Ivan and Katrina on mouse populations before, during, and after these hurricanes. Analysis of the data was performed through contingency tables and Wilcoxon signed-rank tests. The results of the analysis show that the Alabama beach mouse has the ability to survive hurricanes in the future, if they are not successive. The Alabama beach mouse possesses certain traits that make it more vulnerable to extinction in the near future by environmental change, such as greater than normal disturbances both from humans (i.e. habitat loss and fragmentation) and the natural environment (i.e. hurricanes and climate change.) I postulate that the Alabama beach mouse population will be completely extirpated from Gulf Shores in the event of successive major hurricanes in the future. The intended result of this study is not only to find out how the Alabama beach mouse may be affected by global environmental change, but to contribute to the literature concerning the species to be used in effective management strategies.
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    Population dynamics of sugar maple (Acer saccharum Marsh.) at the southern portion of its range: implications for range migration and succession
    (University of Alabama Libraries, 2011) Turberville, Craig Marcus; Hart, Justin L.; University of Alabama Tuscaloosa
    Evidence for climate change driven range migration exists for a variety of tree species in eastern North America. Northward range migration for tree species in the region requires a decrease in population density near the southern range boundary coupled with an increase in population density at the northern range boundary. Sugar maple (Acer saccharum Marsh.) is one such species that has been projected by some biogeographic models to shift north in accord with climate. However, a widespread pattern of increased sugar maple density has been reported in the forest science literature from a variety of sites throughout the species' range. This pattern is linked to a complex of interacting factors and has been hypothesized to represent a positive feedback that facilitates sugar maple regeneration. The primary goal of my study was to test which of these hypotheses (range migration or succession) was correct for the southern portion of the sugar maple range. I used Forest Inventory and Analysis program data to compare region-wide population dynamics for this species on a plot-by-plot basis. Changes in frequency, density, and dominance of sugar maple trees and seedlings were compared over multiple years for the states of Alabama, Kentucky, North Carolina, Tennessee, Virginia, and West Virginia. Plot data for all states were combined to determine changes in frequency, density, and dominance for the contiguous and non-contiguous regions of sugar maple's southern range portion. Results indicated increases in frequency, density, and dominance of sugar maple within its contiguous range coupled with decreases outside of the contiguous range. It is postulated based on these data that sugar maple's southern range boundary will remain stabilized while the northern boundary will continue to migrate with increasing global temperatures.