黄河三角洲滩涂贝类栖息地的时空动态遥感监测

Remote Sensing Monitoring of the Spatio-Temporal Dynamics of Mudflat Shellfish Habitat in the Yellow River Delta

中文关键词: 滩涂贝类  栖息地  时空动态  遥感  黄河三角洲

英文关键词: Mudflat shellfish  Habitat  Spatio-temporal dynamics  Remote sensing  Yellow River Delta

中文摘要:

      基于遥感和GIS(geographic information system)技术，以1986—2017年间潮位最低的6个时相的Landsat影像数据为数据源，以瞬时水边线为下边界，以围垦大堤、养殖池塘、平均高潮线和植被线为上边界，提取黄河三角洲滩涂贝类栖息地信息，分析30年来贝类栖息地的时空变动。结果显示，1986—2017年贝类栖息地面积呈持续下降趋势，由1986年的1188 km2减少为2017年的396 km2；1993—2001年和2008—2013年2个时段变化最为显著，年均减少面积均约为34 km2。空间上，以刁口段变化最为剧烈，除1986—1993年下边界略向海扩张外，其他时段上边界向海推进、下边界向陆蚀退，面积大幅减少。河口段上边界基本稳定，下边界由于黄河入海水沙变化和海洋动力侵蚀的双重作用，淤积和蚀退交替进行，但总体上面积变化不大。黄河三角洲滩涂贝类栖息地时空变动影响因素差异明显，刁口段和莱州湾段主要由于滩涂盐田、水产养殖池塘和工程建设占用，河口段主要因为黄河入海水沙变动和海洋动力侵蚀，由于港口和油田建设，东营港及邻近段栖息地功能全部丧失。

英文摘要:

      Mudflat in the Yellow River Delta is the main production region of shellfish in Shandong Province. To enable economic development, the mudflat was greatly exploited, natural condition of the mudflat was disturbed, and the shellfish habitat was constantly subjected to changes. Based on remote sensing (RS) data and geographic information system (GIS) technology, the mudflat shellfish habitat in the Yellow River Delta data were obtained, and its spatio-temporal variation over the past 30 years was analyzed. For this study, a collection of Landsat images taken during the lowest tidal levels during 1986—2017 were selected as the data source and six images were used in the study. To extract the mudflat shellfish habitat, we chose the instantaneous waterline as the lower boundary and the reclamation dyke, aquaculture pond, or mean high tide line combined with vegetation line as the upper boundary. The results showed that the shellfish habitat area continued to decline from 1986 to 2017, from 1188 km2 in 1986 to 396 km2 in 2017. The variations were the most obvious during 1993—2001 and 2008—2013, and the average annual reduction area was approximately 34 km2. In terms of space, the Diaokou section showed a drastic variation, and the lower boundary expanded slightly to the sea during 1986—1993. However, the upper boundary moved toward the sea and the lower boundary retreated to the land during all other periods, and the area was greatly reduced. As for the estuary, its upper boundary was stable. At the lower boundary, deposition and erosion alternated due to the dual effects of runoff, sand transportation, and marine dynamic erosion, but the area changed only slightly on the whole. The factors influencing spatio-temporal changes in shellfish habitat were evidently different. Occupation by salt fields, aquaculture ponds, and engineering constructions were the main reasons for the changes in the Diaokou and Laizhou Bay sections. The estuary was mainly affected by changes in runoff, sand transportation, and marine dynamic erosion. However, in the Dongying Harbor and its adjacent section, habitat function was completely lost because of the construction of ports and oilfields.