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Abstract

Spatially-organized patches primarily composed of Alpine avens (Geum rossii) on Pikes Peak, CO give the tundra of the 14,000 ft. mountain a freckled appearance. The mechanisms causing formation and maintenance of these patches were examined using parameters such as vegetation height, species abundance, micro-topography, C:N ratios of soils and plants, and soil moisture. This study focused on eight patches by evaluating the above parameters along eight, horizontal 15-18 m transects that ran through the centers of the patches. Shockingly, vegetation height was two times greater within the patch compared to open tundra. This suggests nutrient accumulation within the patch parameters. In this thesis we analyze abiotic, top-down and bottom-up processes, to evaluate these patches. We conclude that this ecosystem is a bi-stable dynamical structure (Lotka-Volterra). In addition, scale-dependent feedback mechanisms (short-distance facilitation and long-distance inhibition) may be a primary contributor to patch formation and maintenance.

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