Date of Award

9-2009

Degree Name

MS in Biological Sciences

Department

Biological Sciences

Advisor

V.L. Holland

Abstract

The objective of this study was to assess the above-ground factors affecting the establishment and recovery of the dominant chaparral shrub Adenostoma fasciculatum (chamise) on the Rocky Canyon granite mine.

Attempts to restore the California chaparral have been challenging and few successful efforts have been documented. However, the California chaparral can fully recover from fire in as little as 10-15 years. Factors affecting chamise seedling establishment were tested by planting chamise seed in forty eight 1square meter plots managed to test the effects of interspecific competition with native postfire vegetation, post-mining volunteer vegetation, and intraspecific only competition. Plots were managed and observed from December 2004 to May 2006. Half of the 48 plots were summer irrigated throughout the first growing season to test the addition of water on growth and survivability. Nearly all chamise seedlings exposed to competition from either native or non-native vegetation perished within the first summer. Seedlings in plots where interspecific competition was removed experienced significantly higher germination and higher survival. Seedlings in the irrigated plots with competition removed, grew on average 18cm taller and had 27% more coverage per plot than non-irrigated with competition removed. They were also 4 times more likely to survive. The results of this study clearly show that chamise seedlings are not strong competitors when exposed to either native herbaceous post-fire vegetation or non-native weedy vegetation. Restoration of chamise at Rocky Canyon will require removal of all competing species during the first year of establishment. Irrigation is not required for successful germination and establishment but will result in higher survival and faster growth.

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