三峡水库运行后洞庭湖洲滩小型兽类群落状况

The Situation of Small Mammal Community in Beach of Dongting Lake after the Official Operation of the Three Gorges Reservoir

为了探究三峡工程建成运行后洞庭湖区洲滩生境中小型兽类的群落状况,对洞庭湖区洲滩生境的小型兽类进行调查。调查采用铗日法,于2010至2018年,对洞庭湖区洲滩小型兽类群落的多样性进行了调查,并计算优势度、群落多样性指数、均匀性指数。对多样性指数采用t值法进行比较,各年份、生境的捕获率及鼠种组成差异则采用卡方检验。2010至2018年,共布放34116铗日,捕获可以分辨种类的样本2129只,主要有啮齿目(Rodentia)和鼩形目(Soricomorpha)2类,共7种,分别是啮齿目的东方田鼠(Microtus fortis)、黑线姬鼠(Apodemus agrarius)、褐家鼠(Rattus norvegicus)、巢鼠(Micromys minutes)、社鼠(Niviventer confucianus)、黄毛鼠(R.losea)和鼩形目的臭鼩(Suncus murinus)。总捕获率为6.36%,东方田鼠、黑线姬鼠捕获率较高,分别为1.83%、3.94%。从小型兽类组成看,黑线姬鼠和东方田鼠在群落中组成的比例较高,分别为63.18%和29.26%。在调查的5类生境中,植被组成以苔草(Carex sp.)、南荻(Miscanthus sp.)和美洲黑杨(Populus deltoides)为主的生境小型兽类群落多样性指数(1.0772)和均匀度指数(0.6662)均最大,其次是以苔草为主的生境(多样性指数和均匀度指数分别为0.9275、0.5723)、以南荻为主的生境(多样性指数和均匀度指数分别为0.8856、0.5502)和以苔草加南荻为主的生境(多样性指数和均匀度指数分别为0.7756、0.4819),以美洲黑杨为主的生境多样性指数(0.3236)和均匀度指数(0.1806)最低,但其优势度最高,为0.8812。结果表明,随着三峡工程的运行,洞庭湖区植被演替发生了变化,从而引起小型兽类群落动态的变化。在洞庭湖洲滩上,生境越复杂,小型兽类物种多样性越高。单一生境下,人类活动干扰程度越大,小型兽类物种多样性越低。目前,黑线姬鼠已经成为洞庭湖洲滩生境的第一优势鼠种。

In order to explore the community status of small mammals in Dongting Lake area after the Three Gorges Project,the small mammals in the marshland habitat of Dongting Lake area were investigated.From 2010 to 2018,the diversity of small animal communities in the marshland habitat of Dongting Lake area was investigated by snap traps,and the dominance concentration index,community diversity index and evenness index were calculated.The diversity index was compared by t value method,and the capture rate and rodent species composition of each year and habitat were tested by Chi-square test.The results of investigation as follow.From 2010 to 2018,a total of 34116 traps were placed,2129 samples of distinguishable species were captured.Rodentia and Soricomorpha were the main species of small mammals captured in Dongting Lake beach habitat,including 7 species,Microtus fortis,Apodemus agrarius,Rattus norvegicus,Micromys minutes,Niviventer confucianus,R.losea and Suncus murinus.The total capture rate is 6.36%,among them,the capture rate of Microtus fortis and A.agrarius was higher,was 1.83%and 3.94%respectively(Table 1).From the composition of small mammals species in Dongting Lake beach,the dominant species are A.agrarius and Microtus fortis,and their proportion in the community is 63.18%and 29.26%respectively(Table 2).Among the five types of habitats investigated,the diversity index(1.0772)and evenness index(0.6662)of the small animal community in the habitats mainly composed of Carex sp.+Miscanthus sp.+Populus deltoides were the largest.It was followed by habitats dominated by Carex sp.(diversity index 0.9275 and evenness index 0.5723);habitats dominated by Miscanthus sacchariflorus(diversity index 0.8856 and evenness index 0.5502);and habitats dominated by Carex sp.+Miscanthus sp.(diversity index 0.7756 and evenness index 0.4819).The diversity index(0.3236)and evenness index(0.1806)of the habitat dominated by P.deltoides was the lowest,but the dominance concentration index was the highest(0.8812)(Table 6).The results showed that with the operation of the Three Gorges Project,the vegetation succession in Dongting Lake area changed,which caused the dynamic change of the small mammal community.On the marshland of Dongting Lake,the more complex the habitat,the higher the diversity of small mammal species.In the single habitat,the greater the interference of human activities,the lower the diversity of small animal species.At present,the A.agrarius has become the first dominant rodent species in the marshland habitat of Dongting Lake.