| 摘要: |
| 半干旱内陆地区的湖泊湿地是一种特殊的生态系统,季节和年际时间尺度上的湖泊水文变化对湖泊湿地生态结构和功能有着重要影响.近20年来,月亮泡湖泊湿地经历了自然和人为因素共同作用下的水文波动过程.为了实现大尺度地表生态年内/年际变化检测,更好地了解湖泊年际水淹范围及其水淹频次对内陆湖滨湿地生态的影响,基于1994—2018年Landsat TM/OLI影像数据(30 m),首先,计算提取月亮泡的年际水体信息和水淹频次,进而获取湖泊年际淹没范围.其次,采用综合生态指数变化检测法提取生态信息,选取3个标准观测年(1995、2006、2016年),从年内变化和年际变化视角分级评价了研究区生态变化,并分析了水淹频次与湿地生态变化的关系.最终,现有研究表明:湖泊年际水淹区主要分布在月亮泡的北侧与西侧尾闾,月亮泡湖泊湿地北侧的年际水淹频次更为显著.湖泊面积的扩展与自然湿地的减少是月亮泡水淹区域的主要变化类型.在这种变化情况下,研究区水体指数累积量的增加与植被指数累积量的衰减成为显著的生态变化特点.月亮泡湖泊年际水淹频次在一定时间和空间上影响着水淹区域的植被生产能力,水淹的低频波动是研究区植被累积量增加的关键因子.因此,在湿地生态恢复与管理过程中,维持合理的水文波动,恢复月亮泡北侧与西侧沼泽湿地是该区域内生态保护的核心措施. |
| 关键词: 遥感反演 植被生态 水淹频次 时空变化 月亮泡湿地 |
| DOI：10.18307/2022.0421 |
| 分类号: |
| 基金项目:博士科研启动基金项目(801002020107)、吉林省教育厅“十三五”科学技术研究项目(JJKH20170005KJ)和国家重点研发计划项目(2016YFB0501502)联合资助. |
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| Remote sensing monitoring of ecological changes in Lake Yueliang wetland and its response to inundation frequency in Western Songnen Plain during 1994-2018 |
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Li Xiaodong1,2, Song Kaishan2, Yan Shougang3
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1.Shandong Key Laboratory of Eco-Environmental Science for Yellow River Delta, Binzhou University, Binzhou 256603, P. R. China;2.Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, CAS, Changchun 130102, P. R. China;3.College of Tourism, Resources and Environment, Zaozhuang University, Zaozhuang 277160, P. R. China
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| Abstract: |
| Wetland in the semiarid inland is a special ecosystem, as its hydrological pulse over seasonal and inter-annual time scales strongly affects the wetland structure and ecological function. Over the past 20 years, the Lake Yueliang wetland is undergoing a degradation caused by natural and human impacts. The paper focuses on how to detect the annual and interannual changes at a large scale and the objective is to understand the impact of inundation range and frequency on inland wetland. Based on Landsat TM/OLI imagery data (30 m) from 1994 to 2018, firstly, we calculated interannual information of water body and inundation frequency to extract the inundation area of Lake Yueliang. Secondly, the remote sensing ecological indexes (MNDWI, NDVI and NDSI) were extract for monitoring the ecological change in the study area. Finally, the observation period was divided into three standard years (1995, 2006 and 2016), and further graded and evaluated the ecological changes included the annual change and the interannual change were further graded and evaluated. The results showed that the flooded areas of the Lake Yueliang mainly distributed in the northern and western lake. Meanwhile, the fluctuation frequency of inundation in the northern part is more significant than other parts. From 1994 to 2018, the main ecological changes is characterized by the expansion of water body and the decreased marsh. In this case, the ecological changes were characterized by the increase of the water index (MNDWI) cumulant and the decline of the vegetation index (NDVI) cumulant. The flooding frequency of the lake affected the vegetation productivity in flooded area, and the flooding fluctuation with the low frequency was a critical factor to increase the vegetation accumulation in the study area. Therefore, for the wetland ecological restoration and management, maintaining the existing lake area and restoring the swamps on the northern and western lake are the keys. |
| Key words: Remote sensing retrieval vegetation ecology inundation fluctuation frequency spatio-temporal change Lake Yueliang wetland |
