辽河口盐地碱蓬湿地景观破碎化及驱动机制

湿地景观破碎化的加剧严重影响了湿地生物多样性保护和湿地生态系统服务功能的维持,本研究以辽河口盐地碱蓬(Suaeda salsa)湿地为研究对象,基于GIS平台构建1985—2019年间湿地景观数据库,定量分析湿地景观破碎化特征及其驱动因素。结果表明:1985—2019年间,辽河口盐地碱蓬湿地呈退化趋势,具体表现为湿地面积萎缩,湿地景观破碎化加剧。盐地碱蓬湿地面积在1988年达到最大值4158.81 hm~2,景观聚集度较高,此后,湿地景观破碎度出现先增大后减小再增大的波动变化,2003年和2019年盐地碱蓬湿地景观破碎化最为严重,破碎度分别达到5.90和7.89;影响辽河口盐地碱蓬湿地景观破碎化主要驱动因素为人为开发活动和水文过程;景观破碎化的整体上升趋势与道路修建、农田开发、水产养殖、径流量和输沙量有较好的空间对应关系,道路修建、农田开发和水产养殖面积的增加以及年径流量的减少是导致盐地碱蓬湿地景观破碎化的主导因素。

Landscape fragmentation and driving mechanism of Suaeda salsa wetland in Liaohe Estuary

The intensification of wetland landscape fragmentation has seriously affected the protection of wetland biodiversity and the maintenance of wetland ecosystem service functions. This study took the Suaeda salsa wetland in the Liaohe River Estuary as the research object, and constructed the wetland landscape database from 1985 to 2019 based on the GIS platform, quantitative analysis of wetland landscape fragmentation characteristics and its driving factors. The results showed that from 1985 to 2019, the Suaeda salsa wetland in the Liaohe River Estuary showed a degrading trend, which was manifested in the shrinkage of wetland area and increased fragmentation of wetland landscape. The area of Suaeda salsa wetland reached its maximum of 4, 158.81 hectares in 1988, and the degree of landscape aggregation was relatively high. After that, the wetland landscape fragmentation first increased, then decreased and finally increased. Suaeda salsa wetland landscape fragmentation in 2003 and 2019 was the most serious, with fragmentation degrees reaching 5.90 and 7.89, respectively; the main driving factors affecting the landscape fragmentation of Suaeda salsa wetland in the Liaohe River Estuary were man-made development activities and hydrological processes; the overall upward trend of landscape fragmentation was related to road construction and farmland development. There was a good spatial correspondence between aquaculture, runoff and sediment transport. Road construction, farmland development, increase of aquaculture area, and reduction of runoff and sediment transport were the main factors leading to the fragmentation of the Suaeda salsa wetland landscape.