吉林省西部湿地动态过程及生态环境效应分析

Wetland Dynamics and Ecological and Environmental Impacts in West Jilin Province

湿地不仅是一种重要的资源，还具有巨大的环境功能和生态效益。湿地面积减少、功能退化引起了严重的区域生态环境问题。为定量分析湿地退化过程以及由此带来的生态环境效应，本文选择吉林省西部地区为研究区，基于1930年、1954年的土地利用数据，以厦1986年、1996年、2000年的遥感影像数据，利用ARCGIS数据集成分析平台，研究了该区湿地从1930年-2000年的时空变化规律，计算了湿地在各个阶段的动态度和湿地的转出贡献率。结果表明，从1930年到2000年的70年间，本区湿地面积大幅度减少，沼泽湿地面积从1930年的123．7×10^4hm^2，2000年仪为22．8×104hm^2，湿地从一种主要的土地利用类型（占总面积27％）下降为微量类型（5％）；从湿地的空间变化来看，各阶段的湿地都在减少，但各阶段的湿地减少程度和方式差别较大；从湿地转出贡献率看，湿地不仅被大规模开垦，而且也在迅速退化，以及大量转化为盐碱地。随着湿地的大量丧失，湿地的调节气候、调节河川径流、降解污染物、防止侵蚀、抗洪减灾和维护区域生态平衡等多种环境功能大幅度减弱甚至丧失．加速恶化了研究区脆弱的生态环境。

Wetlands are not only a key resource but beneficial to environment and ecological system. Losses and degradation of Wetlands have been evolving into serious environmental problems in the recent decades. In this paper, West Jilin province was selected as study area to analyze the changing processes of wetlands as well as its impacts on the environment. Dynamic changing process of wetlands were studied over the periods of 1930 - 2000 by using land use data in 1930, 1954, 1986, 1996, 2000. The indices of dynamic degree of wetland, contribution degree of wetland into other landscape type in different periods were calculated by using the software of ARCGIS. The spatio-temporal dynamic process of wetland was analyzed. The results showed that from 1930 to 2000, wetland has experienced substantial losses, with an area of 123.7 × 10^4 ha in 1930 down to 22.8 × 10^4 ha in 2000, a decrease of 82%. The percentage of wetland occupying total land decreased from 27 percent to 5 percent over the periods. From the point of spatial change of wetland losses, wetlands underwent losses in all periods, but wetland losses have different features in different periods, the Period 1 and period 2 were the major ones in wetland loss; From the point of contribution degree of wetland into other landscape type, wetlands has been not only reclaimed at large scale but degrading rapidly and turning into saline-alkaline land in large quantities, and the reclamation of wetland is the main driving force in the study area. Losses and degradation of wetlands are severely weakening the function of ecological service that wetland provided. Concretely, the Impacts of the wetland losses on the environment and ecology in the study area were prevalent： the regional climate underwent great changes with the features of temperature climbing up and the precipitation declining as well as more natural disasters during the periods of 1930- 2000. The function of purifying water performed by the wetlands was undermined. As a result, eutrophication and water pollution have been getting more and more serious. Wetland vegetation and wetland resources as well as biodiversity were seriously threatened. In a word, the change of wetlands deteriorated the ecology and environment in the study area. This study provides recommendations for regional land planning and suggestions for regional sustainable development.