汉江上游1988-2007年间景观格局变化分析

为研究陕西省境内汉江流域水电开发后区域景观格局时空演变,根据1988,2000和2007年汉江上游地区遥感影像,通过遥感解译,利用GIS缓冲区分析分别研究了汉江上游整体和500,1 000,5 000m缓冲区内景观格局变化。结果表明:(1)汉江上游1988年以来水域呈持续增加趋势,耕地呈现持续"落势",全时段景观格局处于不平衡态,双向转换较频繁。但有向着有利于区域生态改善方向转变的趋势。(2)从景观破碎化、景观形状和景观多样性3个角度分析了研究区景观格局变化,1988-2000年该区景观格局破碎化程度增加,形状趋向复杂,景观趋向多样化;2000-2007年该区景观破碎化程度减小,形状趋向规则化,景观多样性减小,表明景观格局向着有利于区域生态改善的方向转变。(3)汉江上游水电7级梯度开发对沿河500m缓冲区内景观格局影响最显著。

Change of Landscape Pattern in Upper Reaches of Hanjiang River During 1988 to 2007

In order to study the spatial and temporal evolution of the regional landscape in Hanjiang River in Shaanxi Province after the construction of hydropower system,remote sensing images of 1988,2000 and 2007 were interpreted and GIS buffer analysis was applied with widths of 500,1 000 and 5 000 m.The results indicated that water areas showed an increasing trend,while the arable land displayed a steady decreasing trend in the study area since 1988.During the sudied period,landscape pattern was in an unbalanced state with frequent two-way conversions,towards the direction that is beneficial for improving the regional ecology.According to the analysis on landscape fragmentation,landscape diversity and landscape shapes,the degree of landscape fragmentation pattern of the study area increased between 1988 and 2000,and the shape became more complex and landscapes was diversified.Between 2000 and 2007,the degree of landscape fragmentation reduced,the shape became more regular and the landscape diversity decreased.These evidences indicated that the landscape pattern experienced a regional ecological improvement.It can be concluded that the hydropower development has exerted great influences on the landscapes in the study area.