退田还湖工程对西洞庭湖湿地资源的影响及驱动力分析

应用GIS和RS技术,对西洞庭湖湿地退田还湖工程实施前(1996年)和工程实施后(2004年)2期TM遥感影像进行了解译、分析和处理,并探讨了工程实施前后土地利用变化情况。结果表明,退田还湖工程效果明显,西洞庭湖的湿地面积增加了8 657.82hm2,占湿地总面积的17.81%。其中核心区、缓冲区、实验区的湿地面积分别增加了548.55 hm2,368.46 hm2,2 331.9hm2;同时核心区泥沙淤积严重,泥滩面积增加了1 540.35hm2,占核心区湿地总面积的16.38%。实验区一些林地主要转化为建筑用地、旱地和芦苇滩地,一些泥沙滩地和苔草滩地主要转化为人工湿地。但总体上,西洞庭湖湿地面积呈增加趋势,其直接驱动力为退田还湖工程。

Analysis on the Driving Force of the Returning Farmland to Lake Project and Its Impacts on Wetland Resources of West Dongting Lake

Based on the interpretation of TM remote sensing images of West Dongting Lake of two periods 1996 and 2004,a study was conducted on land use cover changes and their rules using transfer matrix.Results showed that from 1996 to 2004,the project of returning farmland to lake made wetland area increase by 8657.82 ha,accounting for 17.81% of the whole wetlands area.The areas of the core zone,buffer zone,experimental zone increased by 548.55 ha,368.46 ha and 2331.9 ha respectively.Because the study area is lowland lake plain and poor drainage.The flood plain area of the core zone increased by 1540.35 ha,accounting for 16.38% of the core zone wetland,Sediment deposition is heavy.In the buffer zone and experimental zone,due to the economic driving effect,forest land was mainly transformed into building land,dry land and reed land.Sediment flood plains and Carex beach mainly changed into artificial wetland.Generally speaking,the wetland area of the West Dongting Lake was in an increasing trend.