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全文摘要次数: 76 全文下载次数: 116
引用本文:

DOI:

10.11834/jrs.20210606

收稿日期:

2020-12-31

修改日期:

2021-09-14

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江苏盐城滨海湿地系统格局变化及其对丹顶鹤生境的影响
李景霞, 付碧宏
中国科学院空天信息创新研究院
摘要:

世界遗产地江苏盐城滨海湿地是亚洲最重要的丹顶鹤越冬栖息地之一,近几十年来,由于农业、工业、水产养殖业及城镇化等人类活动的加强,湿地系统的格局发生了巨大变化,丹顶鹤适宜生境出现急剧退化。本研究利用1989-2019年间的多时相遥感数据对盐城滨海湿地进行分类,分析湿地系统的格局变化及丹顶鹤生境连接度的动态变化。研究结果表明,过去30年盐城滨海湿地中自然湿地呈现快速退化,其面积减少49.46%;而人工湿地面积增长69.24%,其面积增加主要通过占用自然湿地和围垦填海的方式来实现,围垦重心具有自北向南和从陆到海方向迁移的趋势。其中,作为丹顶鹤适宜生境的碱蓬盐沼和盐碱地的面积减少了489.10 km2,适宜生境面积占比从1989年19.88%降至2019年4.36%。结构连接度计算结果显示,适宜生境斑块的连接度指数从1.83下降至1.30,斑块间距离增大,破碎化加剧;而功能连接度的计算结果显示,2019年整体连接度指数和概率连接度指数均小于0.01,连接网络总体破碎,适宜生境连接网络存在于小区域范围,区域连接网络主要集中在中介度指数高的遗产地核心区和条子泥湿地,它们是丹顶鹤适宜生境的关键节点。遗产地核心区自2014年实行退耕还湿、退渔还湿等措施以来,丹顶鹤适宜生境有了很大改善。建议除了加强对现有丹顶鹤适宜生境区域的科学保护外,应加大对关键节点自然湿地的恢复力度,提高丹顶鹤适宜生境斑块间的连接度。

Pattern Change of Coastal Wetland System and its Dynamic Impact on Habitat of Red-Crowned Cranes in Yancheng, Jiangsu Province
Abstract:

Objective The Yancheng coastal wetland in Jiangsu province, as a UNESCO (United Nations Educational, Scientific and Cultural Organization) natural heritage site with an area of 2687 km2, is one of the most important habitats for overwintering of red-crowned cranes in Asia. In recent decades, due to the combined effects of intensive human activities such as industry, agriculture, aquaculture and urbanization, the pattern of coastal wetland system and the suitable habitat for red-crowned cranes have changed dramatically. Therefore, it is a great importance to effectively detect the spatio-temporal variation pattern of coastal wetland system and explore its key impact factors in order to protect the coastal wetland and conserve its biodiversity. At present, the research on land cover change in the Yancheng coastal wetland is insufficient to the species habitat monitoring. It is necessary to conduct further study on the suitable habitat for red-crowned cranes in a long-term and large regional scale. Method In this study, the multi-temporal and multi-source remote sensing data like Landsat TM/OLI data during 1989 to 2019 and Sentinel-2 data in 2019 are used to analyze the features of spatio-temporal variation in the Yancheng coastal wetland. Firstly, the classification system and image interpretation symbols of study area were established to draw the maps of classification and transfer distribution in six periods during 1989 to 2019. Then, the structural and functional connectivity of suitable habitat for red-crowned cranes were evaluated based on the species diffusion ability. Finally, the key ecological nodes for overwintering of red-crowned cranes were evaluated. Result Our results show that the eco-environment of natural wetland has degraded rapidly, with an area loss of 49.46%. In contrast, the artificial wetland increased with 69.24%, which was mainly realized by occupying the natural wetland and reclaiming the tidal flat. The center of reclamation has a tendency of migrating from north to south and from coastal land to sea. The area of seepweed saltmarsh and alkaline land as suitable habitat decreased by 489.10 km2, with a proportion decreased from 19.88% in 1989 to 4.36% in 2019. As for structural connectivity, our results show that the connectance index of suitable habitat patches had decreased from 1.83 to 1.30, showing a downward trend. The distance between the patches increased and the fragmentation intensified. At the same time, the estimations of functional connectivity index show that the integral index and probability index of connectivity in 2019 are both less than 0.01. The functional connectivity has decreased and the connection network is generally broken with only a small part of connection network with high betweenness centrality index. They are existing in the core area of UNESCO natural heritage site and the Tiaozini region. They are also the key ecological nodes for red-crowned cranes habitat. Conclusion In summary, the connectivity of suitable habitat for red-crowned cranes has decreased sharply because of land cover change in the UNESCO natural heritage site--Yancheng coastal wetland in the past 30 years. However, the habitat for red-crowned cranes has been greatly improved since the core area has reverted aquaculture pond and cultivated land to natural wetland in 2014. In addition to enhancing the scientific conservation of the existing suitable habitat like the core area of UNESCO natural heritage site and Tiaozini region, the key ecological nodes in the natural wetland should be restored in order to improve the connectivity among the habitat patches.

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