【摘要】 河漫滩是众多水生生物的关键生境，其衰退是长江生物多样性退化的主要原因之一。安庆长江江豚保护区位于鄱阳湖和长江干流交汇区下游，江湖复合的水文情势形成了众多沙洲和沿岸浅滩，是长江干流河漫滩最丰富的江段，也是长江干流江豚高密度分布区之一。本研究采用遥感影像解译，分析了2000—2017年安庆保护区江段河漫滩的面积及农业活动的变化。结果显示保护区江段河漫滩总面积为61.81 km~2(SD:16.3 km~2),其在2000至2017年间没有显著变化。2017年，河漫滩上的农田面积为19.70 km~2(SD:10.84 km~2),约占总面积的三分之一。整体上，各水域(10 km尺度)的农田面积与河漫滩面积呈现显著正相关，且拥有较大河漫滩的江段还面临日益加剧的农业活动压力。相比2006年，安庆保护区江豚种群仍然呈现下降趋势，显著增强的农业活动对河漫滩造成的扰动和质量衰退可能是多重影响因素之一。我们建议加强对保护区人类活动的管控，尤其需要重点关注河漫滩保存较好而农业活动快速上升的区域。更多还原

【Abstract】 Floodplains are critical habitats for many aquatic species. However, the rapid loss and degradation of floodplain of the Yangtze River has been recognized as one of the key drivers of the biodiversity loss and decline. The Anqing Yangtze Finless Porpoise Provincial Nature Reserve(hereafter Anqing reserve) is located in the downstream of the confluence region of Poyang Lake and the mainstream of the Yangtze River, embraces numerous sandbars and extensive shoreline shallow waters. The river section within this reserve has the most abundant floodplains and is one of the river sections with the highest porpoise population density across the mainstream of the Yangtze River. Using remote sensing technique, this study analyzes the changes of the floodplain area and the intensity of agricultural activities on the floodplain within the river section of the reserve from 2000 to 2017. Our results suggests that the total area of the floodplains in the reserve is 61.81 km~2(SD: 16.3 km~2), which does not change significantly from 2000 to 2017. Within this time period, the cropland area on the floodplain is 19.70 km~2(SD: 10.84 km~2), occupying about one-third of the total floodplain area. Our analysis on a finer scale(10 km water segment) suggests that the river section with a higher floodplain area tended to not only suffer higher agricultural pressures but also subject to increasing agricultural pressures. Aggravating agricultural pressures increases direct disturbances on the floodplain habitat and leads to habitat degradation, which can be one of the major drivers of the porpoise population decline in the Anqing reserve since 2006. We suggest strengthening the management of human activities in the reserve, especially in areas where the floodplains are well preserved yet are under increasing agricultural pressures.更多还原