盐城自然保护区新洋港河口不同生境冬季鸟类群落组成及其梯度变化

Winter bird community structure and gradient change in different habitats at Xinyanggang Estuary,Yancheng Nature Reserve

沿海湿地是鸟类重要的栖息地,人类活动导致的湿地生境变化对鸟类群落造成了一定的影响。在盐城自然保护区新洋港河口内,人类活动大体上导致了由陆向海方向,形成芦苇沼泽、农田、鱼塘和滩涂4种不同干扰程度的生境。分别在不同生境中设置3条长3 km的样线,对越冬鸟类的种类、数量进行了调查,运用多响应置换过程测试、指示种分析、双向聚类分析和除趋势对应分析等统计方法,研究了不同生境中冬季鸟类的指示物种、群落结构及梯度变化,结果表明:1)4种生境共记录鸟类67种,其中鱼塘生境的鸟类种类最多,为37种;滩涂生境的D'多样性指数在各生境不同时段中为最高,芦苇沼泽生境的H'多样性指数在各生境不同时段中为最高。与其余生境比较,芦苇沼泽、滩涂的均匀度也更高。生境间的差异性与鸟类群落的组成有关。2)MRPP分析表明,芦苇沼泽、农田生境的鸟类组成差异不显著(P>0.05);其余组合各生境间的鸟类组成具有显著差异。灰鹤等9种鸟类可分别作为4种不同生境的指示种。3)双向聚类分析法把12种观测条件分为4大类,与生境划分非常吻合。在剩余信息40%水平上,鸟类可聚为7类。利用12种观测条件作为变量进行DCA排序的结果表明,鸟类类群在轴1上可以分为3个集群,分别为适应开阔水域环境的鸟类、依赖水生植被环境的鸟类和依赖陆地植被环境的鸟类。根据结果分析,生境异质性、干扰程度及潮水涨落等与鸟类多样性组成有密切关系;不同生境具有明显的指示种;鸟类群落结构为适应生境变化而出现一定的梯度变化。应加强芦苇沼泽的保护,在开垦农田、鱼塘和在光滩引入互花米草时应考虑到人类活动对鸟类多样性的影响。

Coastal wetland is one of the important avian habitats, and the wetland habitat changes caused by human activities have had a certain influence on bird community and indicator species in different habitats. Reed swamp, farmland, fishpond, and tidal flat were formed as four types of disturbed habitats which resulted from different human activities in Xinyanggang estuary of Yaneheng Nature Reserve. According to a thorough field study, we sampled 3 three- kilometer-long lines in each habitat to investigate the species and numbers of wintering birds. Then we utilized Multi-response Permutation Procedures （MRPP）, Indicator Species Analysis （ISA）, Two-way Cluster Analysis and Detrended Correspondence Analysis （DCA） to analyze the indicator species, bird community structure and gradient change of wintering birds in different disturbed habitats. Our results showed that： 1 ） A total of 67 bird species were recorded in these four types of habitat, and fishpond had the maximum amount among different habitats, which was counted out 37 species. The D＇ diversity index of tidal flat was the highest in the distinct duration in different habitats respectively, as well as the H＇ diversity index of reed swamp. Compared with other habitats, the evenness index of reed swamp and tidal fiat was also higher. The differences between habitats are related to the composition of bird community. 2） According to MRPP analysis, there was no significant difference of bird community structure between reed swamp and farmland （P 〉0.05）, while it was the opposite between other two habitats of the rest combinations. Grus grus could serve as the indicator species in farmland ; The indicator species in fishpond consist of Larus crassirostri~,Larus ridibundus ,Larus vegae and Ardea cinerea; Meanwhile, the indicator species in tidal fiat were made up of Calidris alpina,Pluvialis squatarola and Numenius arquata; The last but not the least, Gallinula chloropus served as the indicator species in reed swamp. 3） Two-way Cluster Analysis classified 12 observation conditions into 4 groups, and it was highly consistent with different types of habitats. Birds could be clustered into 7 groups on the 40% of the rest information. Further more, birds could be divided into three groups on axis 1 of the DCA analysis using 12 observation conditions as variables： birds adapting the open water, birds depending on the aquatic vegetation and birds depending on the terrestrial vegetation. The results of our study showed that bird diversity could be influenced by habitats heterogeneity, human disturbance and tidal water level; and different habitats had obvious indicator species respectively; in order to adapt to the changes in habitats, bird community structure appeared a certain gradient change. In summary, we should strengthen the protection of reed swamp and other original habitats on which wintering birds depend much, and then take the impact of human activities on the diversity of birds into consideration when we reclaim farmland and fishpond as well as introduce Spartina alterniflora into naked flat.