水利工程建设对自然保护区生态系统的影响

以糯扎渡水利工程及受影响的自然保护区为研究案例,在GIS支持下,应用缓冲区分析法,分析了水利工程建设前后自然保护区景观结构的梯度变化以及水利工程对景观结构的影响;选取分维数、斑块密度、优势度、聚集度等代表性指标揭示了区域景观格局的变化;在此基础上,选取自然性、多样性、稳定性和人为干扰性4项指标建立生态评价指标体系,应用层次分析法确定评价指标的权重,并对评价因子进行等级化处理,评价水利工程对影响区生态质量的影响.结果表明:不同缓冲距离内植被类型呈梯度变化,工程建设对季风常绿阔叶林、竹林、落叶季雨林有较大影响;水利工程建设使区域景观异质性增强,在缓冲距离800m范围内景观格局变化明显;建设前后受影响区生态质量评价表明,水利工程建设导致区域生态质量降低,但降幅不大.

Impacts of hydroelectric project construction on nature reserve and assessment

Taking Nuozhadu hydropower station and its effected Nature Reserve for example, we study the change and its gradient changes in landscape structure caused from hydroelectric project based on GIS and buffer analysis. We choose fractal dimension, patch density, dominance index, etc to quantify the landscape pattern change and link them to naturality, diversity, stability and anthropogenic interference of ecosystem to establish an evaluation system, which is used to estimate the ecological condition of the Nature Reserve. The value of each index is determined by the evaluation system, the weight percentage was decided through Analytical Hierarchy Process (AHP). The result show that vegetation type in different buffer zone appeared gradient changes. Hydroelectric project might have significant impacts on some type of forest such as monsoon evergreen broadleaved forest, bamboo grove and deciduous seasonal rain forest. And the hydroelectric project might enhance landscape heterogeneity intensified. Landscape pattern changed significantly especially within 800-meter buffer zone. The ecological evaluation show, that hydroelectric project may slightly deteriorate ecological condition.