近40年艾比湖湿地自然保护区生态干扰度时空动态及景观格局变化

以新疆艾比湖湿地为研究区,利用1972、1998、2007年及2013年4个时期的Landsat遥感影像作为数据源,并结合湿地的土地覆被状况,参考《全国土地利用分类》建立艾比湖湿地生态干扰类型分类系统。借助生态干扰度指数、景观格局指数以及GIS空间分析方法,探讨艾比湖湿地的生态干扰度的时空动态及景观响应机制。结果表明:(1)1972—2013年,研究区的生态干扰度总体呈现较为稳定的趋势,但其空间分布发生变化。生态干扰度类型之间的转化速率有加快的趋势。(2)1972—2013年,边缘密度指数(ED),平均形状指数(MSI),面积加权的平均斑块分形指数(AWMPFD)及景观分离度(DIVISION)4项景观格局指数大体呈上升的趋势,2013年区域的景观指数较为稳定。(3)景观格局指数与生态干扰程度有密切的一致性。生态干扰度与景观格局指数空间分布相关性大小依次为:边缘密度指数(ED)景观丰度密度(PRD)香农多样性指数(SHDI)平均形状指数(MSI)面积加权的平均斑块分形指数(AWMPFD)景观分离度(DIVISION)。客观系统的认识和评价艾比湖湿地的生态系统及环境,可为干旱区实现自然环境的保护,协调土地利用及环境保护之间的关系提供较为实用的参考。

Analysis of the temporal and spatial dynamics of landscape patterns and hemeroby index of the Ebinur Lake Wetland Nature Reserve, Xinjiang, over the last 40 years

Wetlands are an important part of ecological systems. Wetlands not only provide the survival habitats and resources for plants, animals, and human but also are highly beneficial for the environment. In arid zones in particular, wetlands have received considerable scientific attention. The hemeroby index provides a measure of the magnitude to which the vegetation of an ecological environment deviates from the natural state as a consequence of human activities. It is beneficial to manage rationally for economic development in order to protect the ecological environment. The present study fills a gap in our understanding of the sustainable development of the wetland ecosystem in the Ebinur Lake Wetland Nature Reserve, Xinjiang Uyghur Autonomous Region, China. A hemeroby-type classification system for the Ebinur Lake Wetland Reserve was established based on multiple datasets, including Landsat MSS/TM/ETM+/OLI image data obtained in 1972, 1998, 2007, and 2013. The study explored the spatiotemporal dynamics of hemeroby and the landscape pattern response through hemeroby, landscape pattern, spatial patch, and GIS spatial analyses in the study area. The following results were obtained: (1) From 1972 to 2013, the ecological hemeroby degree for the Ebinur Lake wetland showed a relatively stable trend; however, there were marked changes in its spatial distribution. The distribution of the partially disturbed type of wetland has obviously changed. This indicates that the degree of naturalness of wetland vegetation is unstable and susceptible to human interference in this area. There was a high conversion rate of different hemeroby index (HI) types from 1972 to 2013. Dynamic changes in hemeroby degree are more likely to be attributed to natural, human, and policy-driven forces that result in a comprehensive effect. During the period 1972-2013, changes in natural factors (mean annual evaporation, temperature, and precipitation) and human factors (livestock, population, and GDP) led to change in the distribution of vegetation and Ebinur Lake area, which influenced the degree of naturalness of the ecological system. (2) During the period 1972-2013, there were significant increases in four landscape pattern indices, edge density (ED), mean shape index (MSI), area-weighted mean patch fractal dimension index (AWMPFD), and landscape division (DIVISION). However, in 2013, the regional landscape index was relatively stable. (3) High values of ED and AWMPFD were recorded for areas with a high HI. This shows that landscape patch fragmentation and complexity is higher in areas with a high HI, and that the degree of naturalness is unstable. Low values of patch fragmentation and complexity are mainly concentrated in areas with a low HI. This indicates that landscape pattern indices and the HI have good consistency and correlation with regard to spatial distribution. The HI was positively correlated with DIVISION, AWMPFD, MSI, Shannon''s diversity index, patch richness density, and ED, in a decreasing order of influence. Evaluation of the ecological environment of the Ebinur Lake region provides a practical reference for the protection of the natural environment and resources, and will prove beneficial for the coordinated management of the environmental for sustainable development.