Audrey Hoffa and Christy A. Carello. Metropolitan State College of Denver
Background/Question/Methods Cucumber Gulch Preserve is a fen wetland complex located 3000 meters above sea level in Breckenridge, CO. The Preserve is wedged between the Town of Breckenridge and the base of a major ski resort. In 2006, construction of a new ski gondola required clear cutting a 30-meter wide path through the upland vegetation of the Preserve. The vegetation was mainly old growth and secondary growth subalpine forest. We predicted that the clear cutting disturbance would result in increased diversity of understory plants. We also investigated the effect this clear cutting would have on species composition at incremental distances from the forested edge. Four randomly chosen transect lines with nine 1 m2 sampling quadrats were located within the proposed cut and at three meter increments into the forested edge. Percent cover of herbaceous vegetation was measured every August from 2004-2008.
Results/Conclusions A total of forty five plant species were identified in quadrats in this study. A comparison of baseline data (2004-2005) to post deforestation (2007-2008) data showed a significant increase in plant species diversity within the deforested area of the gondola cut (t=2.032, p=0.008) and 3 meters from the forested edge (t=2.045, p=0.052). Significant differences were not found at both 6 and 9 meters from the forested edge (t=2.048, p=0.172; t=2.042, p=0.104). Encroachment of non-native species did not occur in any of the plots. Species composition change resulted mainly from an increase in, Equisetum arvense, Fragaria virginiana, and graminoid species. The results of this study show that clear cutting does not just effect the immediate area of deforestation, but that it effects the species composition at least 3 meters from the forested edge. Land managers faced with deforestation projects should consider that the actual area of disturbance would extend beyond the immediate area of impact and enact policies to protect surrounding habitat.