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http://hdl.handle.net/2148/174
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| Title: | Plant invasion models-road effects |
| Authors: | Hobelmann, Emily Ann |
| Thesis Advisor: | Dugaw, Christopher |
| Keywords: | Lotka-Volterra two species competition
invasion
diffusion in heterogeneous space
patch models |
| Issue Date: | May-2007 |
| Publisher: | Humboldt State University |
| Abstract: | Invasive, or exotic, plant species are commonly found lining roadsides and tend to favor disturbed areas that have been cleared of vegetation. Construction and maintenance of roads, utility corridors, trails, railways, etc. create disturbances and thus contribute to the establishment of exotic species. Despite the influence of disturbances on invasions, invasion models have yet to fully address the spread of interacting, competing species through heterogeneous landscapes. By considering space as two discrete patches and alternatively, by considering space as a continuous line we model exotic and native populations of plants interacting and dispersing adjacent to a theoretical roadside. A small fraction of the spatial domain in each consideration is treated as road margin where we assume the exotics out-compete the natives; the remainder of the domain is considered interior where the exotic could not invade without the road margin. Initially we assume the road margin is free of any species and the interior has an established native community at carrying capacity. Numerical conditions for which a small amount of exotics released in the road margin can successfully invade the interior are established for both spatial considerations, and the results are qualitatively similar. Bifurcation diagrams for the stability of the equilibrium point at native carrying capacity are generated for the discrete space model. Parameter regions for the exotic competition coefficients indicate that the exotics successfully invading the interior depends on the values of the competition coefficients throughout the region. Results confirm the threat posed to native habitats by exotic plant populations spreading along road networks, underscoring the need for eradication of invasive populations early on in their establishment in disturbed areas adjacent to native populations. |
| Description: | Thesis (M.S.)--Humboldt State University, Environmental Systems, Mathematical Modeling, 2007 |
| URI: | http://hdl.handle.net/2148/174 |
| Appears in Collections: | HSU Masters Theses
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