Geomorphic-centered classification of wetlands on the Qinghai-Tibet Plateau, Western China

Abstract

AbstractIn this paper a geomorphic-centered system was proposed for classifying the wetlands on the Qinghai-Tibet Plateau in western China, where the flora comprises primarily grasses. Although the geomorphic properties (e.g., elevation and morphology) of wetlands form the primary criteria of classification, this system also takes hydrological processes into implicit consideration. It represents an improvement over the hydrogeomorphic perspective as the relative importance of the two components (wetness and landform) of wetlands is clearly differentiated. This geomorphic-centered perspective yields insights into the hydrogeomorphic dynamics of plateau wetlands while indicates their vulnerability to change and degradation indirectly. According to this geomorphic-centered perspective, all plateau wetlands fall into one of the seven types of alpine, piedmont, valley, terrace, floodplain, lacustrine, and riverine in three elevational categories of upland, midland, and lowland. Upland (alpine and piedmont) wetlands with the steepest topography are the most sensitive to change whereas midland (floodplain, terrace and valley) wetlands are less vulnerable to degradation owing to a high water reserve except terrace wetlands. They have a dry surface caused by infrequent hydrological replenishment owing to their higher elevation than the channel. Low lying (lacustrine and riverine) wetlands are the most resilient. The geomorphic-centered perspective developed in this paper provides a framework for improving recognition and management of wetlands on the Plateau. Resilient wetlands can be grazed more intensively without the risk of degradation. Fragile and vulnerable wetlands require careful management to avoid degradation.