Researching Ecological Effect Of Wetland Change In Beijing Region-Take Yeyahu Wetland Example

Wetland is one of the weakest ecological systems in the world. Once the wetland is in danger, regional eco-environment also is destroyed correspondingly. The appearance and deterioration of wentland eco-environment, to some extent, will restrict economic development of this area with continuance, stabilization and exuberance.The major work of this paper will select Ye Yahu wetland region as a research area. According to the traditional theories such as landscape ecology, ecosystem succession, and wetland resume theory, we adopt burgeoning technology, including GIS function spatial analysis, statistics and three-dimensional design, reversion theory of remote sensing, and GPS location technology out of doors, analysis synthetically the dynamic change of wetland resources with hydrology, vegetation and soil; summarize the wetland eco-environmental quality assessment; mainly research eco-environment effect due to the wetland dynamic change including regional soil salinization, vegetation fraction depression, microclimate dry-warm effect and non-point pollution etc.; and then provide decision-making foundation and theoretical guidance for the wetland resume and rebuilt.The results of research as follow: this is a close connection between inverse effect of regional eco-environment and wetland resources deterioration. In wetland area, regional soil salinization has been increasing year by year which is arrived to 21.79 km in 2004. However, soil salinization makes marsh to mid-dry, dry and salty vegetation. The tendency of regional vegetation fraction is from increasing to decreasing as boundary point in 2002. Comparing with 1998's, the area of mid-high and high vegetation falls 71.09% and 99.26% relatively in 2004. And the reduction of vegetation fraction makes soil fertilities correspondingly. The reduction of daily area evapotranspiration verifies circumjacent microclimate shows dryier and warmer tendency. In 2004, the average of daily area evapotranspiration on surface water and land is 5.67mm, decreases 0.08mm comparing with 1998's. Meanwhile, dry-warm microclimate directly causes scarcity of wetland water resource. Recently, non-point pollution has been more serious in Ye Yahu wetland upriver area than Guanting reservoir and Ye Yahu wetland. Non-point pollution directly accelerates the eutrophication of water itself. So water pollution has been reached IV or V grade.