Plant Ecol (2008) 197: 139-151 001 10.1007/...



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Category: Ecological Research

Title: Restoring plant species diversity and community composition in a ponderosa pine-bunchgrass ecosystem

Author: * Laughlin, D.C. , * Bakker, J.D. , * Daniels, M.L. , Moore, M.M., * Casey, C.C. , * Springer, J.D.

Subject: Ecological Restoration, Diversity, Species richness, Ponderosa pine (Pinus ponderosa), Bunchgrass

Abstract: Monitoring of ecological restoration treatments often focuses on changes in community structure and function. We suggest that long-term changes in community composition also need to be explicitly considered when evaluating the success of restoration treatments. In 1992, we initiated an experiment in a ponderosa pine-bunchgrass ecosystem to evaluate responses to restoration treatments: (a) thinning the overstory vegetation ('thinning'), (b) thinning plus forest floor manipulation with periodic prescribed burning ('composite'), and (c) untreated 'control.' Treatments were further stratified by forest patch type: presettlement tree clumps (trees that established prior to the onset of fire exclusion in 1876), patches of retained postsettlement trees, patches where all postsettlement trees were removed, and remnant grass openings. Species richness did not differ among treatments for 10 years, but was highest in the composite treatment in II th and 12th year after initial treatment. Community composition diverged among treatments 5 years after initial treatment, and compositional changes were greatest in the composite treatment. Species richness and composition differed among patch types prior to treatment. Remnant grass patches were the most diverse and presettlement patches were the least diverse. FoJlowing treatment, species richness in the postsettlement removed and retained patches, gradually approached levels found in remnant grass patches. Compositional differences among patch types changed a little by 2005. Species richness at the 2 m2 scale increased only where the overstory was thinned and the understory was burned. However, these changes may not be detectable for many years, and can vary temporally in response to events such as severe droughts. Nonnative species establishment may be reduced by scheduling longer bum intervals or by refraining from burning where fuel loads are not hazardous, though these options may hinder goals of increasing diversity. Restoring species diversity and community composition continues to be more difficult than restoring ecosystem structure and function.

Date: 2008

Type: Journal

Source: Plant Ecology

Identifier: 197:139-151

Publisher: Springer Science and Business Media

Format: PDF

Language: English