Undergraduate Honors Theses

Thesis Defended

Spring 2011

Document Type

Thesis

Department

Ecology and Evolutionary Biology

First Advisor

Nichole Barger

Abstract

Pinyon-Juniper (P-J) ecosystems are extensive throughout the western U.S. and have been expanding into shrublands and grasslands. A variety of tree-removal methods have been used in an attempt to restore herbaceous cover and reduce the risk of catastrophic fire with unknown effects on plant communities. I examined the impact of three different fuels reduction treatments on the local seed bank. The treatments were: mastication, where fuels are mulched and left in the plot; broadcast burn, where fuels are spread evenly across the plot and burned; and pile burn, where fuels are placed in discrete piles and burned. Treatments were adjacent to an untreated control site. The plot subjected to the pile burn treatment had a significantly higher seedling density (P = 0.04) than plot subjected to the broadcast burn treatment. Additionally, the plot subjected to the pile burn treatment had significantly higher species diversity (P = 0.0004) than the control. Artificial seeding, preformed by the Bureau of Land Management, had no effect on seedling density (P > 0.05), but did significantly lower species diversity (P < 0.0001). This study indicates that treatment, most notably the pile burn treatment, has an effect on seedling density and species diversity, while seeding nly affected species diversity.

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