长江口滩涂湿地景观变化对典型水鸟生境适宜性的影响

近年来在海平面上升、长江水沙变化、植被演替等自然因素以及促淤圈围工程、深水航道建设等人为因素的共同作用下，长江口滩涂湿地水鸟适宜生境发生了巨大变化。针对长江口滩涂湿地典型水鸟中的鸻鹬类(Charadriiformes)与雁鸭类(Anseriformes)，采用空间多样性指数、人为干扰度等指标研究1980～2010年长江口滩涂湿地景观变化对两类水鸟生境适宜性的影响。结果表明：两类水鸟的不适宜生境、边缘生境、次级生境面积均呈增长趋势，鸻鹬类共增加682 km2，雁鸭类共增加314 km2。而核心生境面积却呈不同的变化趋势，鸻鹬类减少136 km2，雁鸭类增加232 km2，但鸻鹬类和雁鸭类核心生境面积百分比均分别减少566%和194%。1980～2010年鸻鹬类生境适宜性综合评价指数由092下降到053，雁鸭类由089下降到070，鸻鹬类降幅大于雁鸭类。通过定量分析人为干扰度对水鸟生境的影响，发现鸻鹬类对人类干扰更加敏感，中等强度的人类干扰在一定程度上扩大了雁鸭类的适宜生境面积

EFFECT OF LANDSCAPE CHANGES ON THE HABITAT SUITABILITY FOR TYPICAL WATERBIRDS AT THE YANGTZE ESTUARY

The Yangtze estuary is one of the most important stopover sites in East Asian Australasian flyway for migratory waterbirds. Charadriiformes and Anseriformes are two major waterbird groups in the Yangtze estuary. During the past decades, suitable habitat for waterbirds in the Yangtze estuary has undergone severe changes due to the influences of natural factors (such as sea level rising, flow and sediment changes in the catchment and vegetation succession), as well as anthropic factors (e.g. reclamation, accretion promotion and deep water channel construction). Based on remotly sensed data and field investigation, we studied the land use changes and applied spatial diversity and hemeroby index to evaluate the changes of habitat suitability for Charadriiformes and Anseriformes during the period of 1980-2010. According to the spatial diversity index, the Yangtze estuary was divided into four types, i.e., core habitat, secondary habitat, edge habitat and unsuitable habitat. The results indicated that the area percentages of core habitats decreased by 55.6% and 18.6% for Charadriiformes and Anseriformes, respectively. The area of core habitats decreased by 133 km2 for Charadriiformes and increased by 235 km2 for Anseriformes. The total area of secondary habitats, edge habitats and unsuitable habitats increased by 679 km2 and 311 km2 for Charadriiformes and Anseriformes, respectively. The comprehensive habitat suitability indices (H) for Charadriiformes were 0.92, 0.67, 0.58 and 0.53 for the years 1980, 1990, 2000 and 2010, respectively, with a decrease of 40% from 1980 to 2010. In addition, the comprehensive habitat suitability indices (H) for Anseriformes were 0.89, 0.72, 0.70 and 0.70 for the years 1980, 1990, 2000 and 2010, respectively, with a decrease of 18% during the last thirty years. Moreover, we found that the suitable habitats for Charadriiformes and Anseriformes both decreased more rapidly in the period of 1980-1990 than later periods. According to the spatial diversity indices of different hemeroby types, human disturbance was negatively correlated with the spatial diversity and had negative impacts on the habitat suitability of both Charadriiformes and Anseriformes. The degree of correlation for Charadriiformes was higher than that for Anseriformes. Moderate intensity of human disturbance increased the area of suitable habitat for Anseriformes. In summary, with intensive reclamation at the Yangtze estuary, habitat suitability for Charadriiformes and Anseriformes both decreased during the last thirty years， and habitat suitability for Charadriiformes decreased more rapidly than that for Anseriformes