| Eco-environment water demand is of positive significance to maintain its ecological balance and sustainable development, as well as to keep from damaging the hydrologic functions and related environmental functions of wetland. Therefore, eco-environment water demand of Napahai plateau wetland with its influenced factors and regulating-strategies were examined. In turn, some measures were proposed to guarantee eco-environment water demand of Napahai wetland through protecting and restoring wetland ecosystem health after general analysis of vegetation restoration. Specifically, vegetation restoration can conserve river basin ecosystem, increase soil water content/reservoirs and reduce soil erosion as well. These results would provide insights into the scientific development of plateau wetland. Detailed results were as follows:Based on the analytic hierarchy process theory, eco-environment water demand of Napahai plateau wetland and associated influence were examined using the combination of3S technology and Function method. Results showed that the ideal eco-environment water demand of Napahai wetland was necessary2315.2hm2of water surface area based on the analysis of eco-environment water demand. While the minimum eco-environment water demand of Napahai wetland was approx.1315.2hm2of water surface area. And the moderate eco-environment water demand of this wetland was needed between approx.2315.2hm2and1315.2hm2of water surface area. However, Napahai plateau wetland covered limited water surface area of1024.39hm2inl974,1305.32hm2in1994,1220.74hm2in2000and847hm2in2006. This indicates the water resource of this wetland belonged to shortage situation in all recent decades. Based on the analysis of the local social and economic conditions, overloaded wetland reclaimation, urbanization, and unreasonable tourism development and vegetation deterioration were observe found to affect significantly the eco-environment water demand of Napahai wetland. According to the pratical experiences around the world, revegetation, improving the soil moisture/reservoirs and reducing soil erosion with larger amount, would meet the requirement of eco-environment water demand of Napahai wetland.Five typical vegetation types in Napahai catchment including barren land, populous adenopoda revegetated plot, philadolphus delavayi revegetated plot, grassland and pine forest land were selected to determine soil water content, bulk density and organic carbon content. Subsequently, influencing factors of soil water content were completely understand, which is of positive significance for the protection of the local fragile ecological hydrology and environmental protection and even its implementation of regional sustainable development. Results indicated that soil water content of different vegetation type were much difference in Napahai catchment. Herein, grass land was greatest with45.3%, philadolphus delavayi revegetated plot and pine forest land respectively were following with32.8%and30.1%, while barren land and populous adenopoda revegetated plot only had19.9%and19.8%. Soil reservoirs of different vegetation type were large difference and grass land> philadolphus delavayi revegetated plot> pine forest land> bareren land> populous adenopoda revegetated plot. Soils characteristics of five typical vegetation types were no clear trends. Pearson correlation analysis showed that there were no significant correlations between soil water content and organic carbon, soil texture, vegetation density, surface runoff, but significant correlation with bulk density. The presentation of soil water content is the result of many environmental factors and combination of human disturbance. Indicatively, grassing, a rapid measures of land cover restoration, could quickly improve the surface soil properties and enhance soil water holding capacity.Soil erosion and their influence under different vegetation types in Napahai catchment is of positive significance for soil and water conservation, wetland ecosystem conservation as well as the regional sustainable development. This study investigated five representative plant cover types in Napahai Catchment to establish runoff plots, observe surface runoff and sediment yield. These included barren land, populous adenopoda revegetated plot, philadolphus delavayi revegetated plot, grassland and pine forest land. They were subsequently analyzed to determine their effects on soil erosion. Results showed that surface runoff and sediment yield were reduced with an increase in plant cover. However, different plant cover types produced significantly different results in surface runoff and sediment yield. Surface runoff volume followed the order:barren land> philadolphus delavayi revegetated plot>pine forestland> populous adenopoda revegetated plot>grassland, while sediment yield volume followed the order:barren land> populous adenopoda revegetated plot> philadolphus delavayi revegetated plot> pine forest land> grassland. Rainfall is the motive force of the soil erosion, while vegetation, improving the surface properties and redistribution of rainfall, reduce soil erosion. In addition, gradient, soil water content, gravel, bulk density and soil organic matter were closely correlated to surface runoff and sediment yield in the Napahai Catchment. Grassland revegetation, in particular, would be a good initial step to take to prevent and control surface runoff and sediment yield during ecological restoration of the Napahai Catchment.In conclusion, grassing, a rapid and effective restoration of land cover vegetation, could quickly improve the surface soil properties, enhance soil water holding capacity and reduce soil erosion to conserve eco-environment water demand, protect and restore the ecosystem health of the region. |
PDF Full Text Request