INFLUENCES OF ALPINE ECOSYSTEM RESPONSES TO CLIMATIC CHANGE ON SOIL PROPERTIES ON THE QINGHAI-TIBET PLATEAU, CHINA

Abstract

Alpine ecosystems are quite sensitive to global climatic changes. Drawing from two sets of remote sensing data (1986 and 2000) and field investigations, the ecological index method was used to document ecosystem changes in the Yangtze and Yellow River source regions of central Qinghai-Tibet. Although crucial to understanding alpine ecosystem responses to global climatic changes, and in assessing the potential for their rehabilitation, the impact of such changes on alpine soil characteristics, including structure, composition, water retention, as well as chemical and nutrient contents, is poorly understood. Over a 15-year period (1986-2000), climatic changes led to considerable degradation of alpine meadows and steppes. In the meadows, the surface layers of the soil became coarser, bulk density, porosity and saturated hydraulic conductivity rose, while water-holding capacity decreased. In comparison, steppe soils showed little changes in soil physical properties. Degradation of alpine ecosystems led to large losses in soil available Fe, Mn and Zn. Important losses in soil organic matter (SOM) and total nitrogen (TN) occurred in badly degraded ecosystems. Climate warming in the Qinghai-Tibet Plateau, caused by the impact of greenhouse gas, has resulted in changes of cold alpine ecosystem such as the significant alteration of the soil C and N cycles. © 2007 Elsevier B.V. All rights reserved.