Study On Eco-Hydrological And Vegetation Distribution Pattern In Sand Land-Taking Gahaielesu Sand Land As An Example

The sand land which embedded in grassland area, is a very special type of land use and land cover, and also is a kind of unique natural landscape. Sand land demonstrate the tendency of water centralization comparing with grassland under the same climatic conditions. The mechanism of this phenomenon has mainly clear at present, the moisture balance mode of sand land isn't very clear, but the soil moisture content transport process and influence factors is unclear.A series of studies was conducted to analyze and probe the occurrence features of groundwater, soil moisture absorption and migration, interaction mechanism between the sand vegetation distribution pattern and groundwater systems at different scales in Gahaielesu Sand Land. Some conclusions have been drawn as follows:1 Vegetation distribution patternThe sand unique landforms types bring about more diversified habitat, thus changing the original vegetation of the spatial pattern of vegetation, so the distribution pattern of sand vegetation shows high spatial heterogeneity on landscape scale.The local terrain changes and soil moisture content redistribution influence vegetation spatial pattern of small scale on sand dunes.2 Occurrence features of groundwaterWater plane fluctuating vary with topographical surface ups and downs. Abundant groundwater outcrops on the edge and low-lying areas of the Sand Land.3 Eco-hydrologic characteristic of sand landCompared with typical grassland soil, the sand soil absorb moisture more quickly, moisture leak faster in sand soil, but the evaporation is slower due to the existence of Dry surface layer of sand. Because of this series of eco-hydrologic characteristics, sand land could absorb and hold more water.4 The coupling relations of vegetation and Hydrologic systemThe distribution pattern of sand vegetation in small scale depends on terrain and soil moisture content. Different types of communities distribute on different topographic position of sand dune. The soil moisture content is significantly different inside each community.Xerophytia (Form.Salix gordejevii) distributes on the top of sand dunes, mesophytia(Form. Spiraea aquilegifolia) distributes on schattenseite of sand dunes, Emersiherbosa distributes on the lowland of sand dunes.