艾比湖湿地土地利用/覆被-景观格局和气候变化的生态环境效应研究

借助Arc GIS与ENVI软件,以1998年、2006年和2014年遥感影像Landsat TM/OLI为数据源,得到3期艾比湖湿地自然保护区土地利用/覆被类型图.在空间尺度上将研究区分为3个特定研究单元来分析土地利用/覆被变化特征,并从景观格局和气候变化两个方面来进行生态环境效应研究.通过计算土地利用/覆被类型生态风险指数,从而获得研究区生态安全指数,最终建立艾比湖湿地自然保护区土地利用/覆被类型与生态环境之间的数量关系,并对整体及局部地区进行生态环境质量动态分析.结果表明,水域和其他(裸地和戈壁)是研究区内的优势景观类型.水域的平均斑块面积最大,水域和其他(裸地和戈壁)的最大斑块指数较高,盐碱地和其他(裸地和戈壁)的分维度指数较高,水域和其他(裸地和戈壁)的聚集度指数较大,林草地空间分布离散,破碎化程度高,连通性差.1998—2014年期间多样性指数增加,说明各景观类型所占比例趋于均衡化,作为优势景观类型的湿地对整个景观的控制作用减小,景观异质性增加.1998—2014年间,艾比湖湿地自然保护区总体生态环境指数呈逐步升高趋势,但生态环境质量的改善与恶化同时存在,并在特定研究单元上出现明显的区域分异特征.盐碱地、其他(裸地和戈壁)向湿地及荒漠向其他(裸地和戈壁)的转化是环境改善的主导因素.湿地向水域和其他(裸地和戈壁)的转变是环境恶化的主导因素.据1998—2014年的气象资料,降水量呈下降趋势,降水减少使植物存活率降低,导致植被覆盖率下降,从而影响生态环境的健康发展.另外,在分析驱动机制的基础上,建立了优选多元线性回归方程,结果表明,在景观指数和年径流量中,艾比湖湿地自然保护区生态环境指数的变化与平均斑块面积和分维度指数均呈显著相关.该研究对艾比湖湿地自然保护区土地利用合理规划管理、生态恢复和经济发展政策的制定有着非常重要的意义.

Investigation on eco-environmental effects of land use/cover-landscape pattern and climate change in Ebinur Lake Wetland Nature Reserve

Based on Landsat TM/OLI remote sensing images of 1998, 2006 and 2014, we analyzed the land use/cover changes of the Ebinur Lake areas using ArcGIS and ENVI software. The research area is divided into three specific research units on spatial scale to analyze the land use/cover change. The effects of land use/cover change on eco-environment were analyzed based on the changes of landscape pattern and climate. The regional ecological safety index was calculated from the ecological risk index of land use/cover and quantitative relationship between the land use/cover type in Ebinur Lake Wetland Nature Reserve. Analysis of ecological environment quality was analyzed for the entire study area as well as portions of the study area. The results showed that water and others (bare land and gobi) were the major land cover type in Ebinur Lake Wetland Nature Reserve. Over the past three decades, water had the largest average patch area, water and others had the highest patch area index than the other land use type, while salinized land had the higher dimension index. In addition, the cohesion indices of water and others were higher and showed a smoothing trend, while forest and grassland showed a discrete distribution, high degree of fragmentation, and inferior connectivity. Shannon''s diversity indices showed an increasing trend in Ebinur Lake Wetland Nature Reserve from 1998 to 2014. The overall landscape pattern tended to be equalization, however, the control function of wetland have reduced and landscape heterogeneity have increased. The overall eco-environment index of Ebinur Lake Wetland Nature Reserve had an increase trend from 1998-2014, but improvement and deterioration of eco-environment coexist and the specific portion of the study areas showed significant spatial differences. Transformations from salinized land and others to wetland and from desert to others were major changes of land uses and landscape. Transformation from wetland to salinized and desert was the major environmental degradation in the area. The precipitation showed a decreased trend according to the meteorological data of 1998-2014, and decreased the survival rate of plants which led to the decline of vegetation coverage and affected the healthy development of the ecological environment. A multiple linear regression equation was established based on the analysis of the driving mechanism. The results showed the change of ecological environment index in Ebinur Lake Wetland Nature Reserve was significantly correlated with average patch area, fractal dimension index, and annual runoff. This study provided useful information for future land use planning and management, and policy formulation of ecological restoration and economic development in Ebinur Lake Wetland Nature Reserve.