Conservation and pasture value of remnant trees in a tropical agroecosystem. Rivers, Ariel N. 原文请求 摘    要： Deforestation is continuing at a rapid rate in Central America, contributing to a loss of forest habitat and threatening many endemic species. In Matiguas, Nicaragua, as little as 10of the original forest reserves remain, with cattle pastures now dominating the once forested landscape. The open pastures provide little habitat for endemic wildlife and limit the corridors for animal migration between remaining forest fragments in the region. Remnant pasture trees have the potential to conserve biodiversity at the landscape level, however, farmers prefer to remove the trees for fear that the shade will negatively affect pasture grasses, and thus reduce the available cattle forage. In order to test the hypotheses of the farmers, this study establishes a quantifiable relationship between pasture grasses and three tree species--- Albizia saman, Enterolobium cyclocarpum, and Guazuma ulmifolia---between the months of February and May of 2008. Several tree characteristics were measured and related to pasture productivity and arthropod communities below the trees and within the open pasture, and a General Linear Model and a Wilcoxon signed rank test were used to compare the data. Results indicate that pasture productivity is not negatively impacted by trees, and that individual tree species affect both pasture grasses and arthropod communities differently. The findings of this study can provide guidance for planning environmentally focused silvopastoral systems and can guide future research efforts. 分 类 号： 第二语种摘要： 正文语种： ENG 授予单位： San Jose State University. 学科专业： 导师姓名： O'Malley, Rachel, 授予学位： M.S. 授予年份： 2009 页    码： 65 p. 馆 藏 号： AAI1470989