Community Structures and Erosion Control Ability of Plantations in Xiaojiang Drainage Basin, China

摘要

Xiaojiang drainage basin is one of the regions suffering from serious erosion and ecological degeneration due to the climate, geological and geomorphological conditions and the heavy human activities. Reforestation, which has been done since 1980s in the region, is an effective measure for the ecological restoration. Four types of plantations, i.e., Eucalyptus spp., Acacia mearnsii, Leucaena leucocephala an d Pinus yunnanensis are investigated in the sample plots. Development processes and community structures of the tree layers, shrub layers and grass layers are studied with the "ergodic hypothesis" method and the index of species richness, coverage, importance value and Shannon_Wiener index et al, and erosion control abilities of the four types of plantations are compared in this paper. The result shows that the plantations of Acacia mearnsii and Leucaena leucocephala grow faster, which have higher crown coverages and stronger erosion control abilities than that of Pinus yunnanensis and Eucalyptus spp.. The Pinus yunnanensis plantation has a higher secondary understory biodiversity, the Eucalyptus spp. plantation has a high secondary understory biodiversity, but the plantations of Acacia mearnsii and Leucaena leucocephala have low secondary understory biodiversities. Study in this paper shows that the four types of plantation have distinct effects in promoting plant diversity and have different erosion control abilities. So plantation species selection and association mode should be considered in the process of reforestation for ecological restoration.