Avian Community Of Reed Wetland In A Riparian Area In Taihu Lake

During June.2010and May.2011,in the Suzhou taihu lake national wetland park and thelakeside reed wetland,we studied the avian community structures.The characteristics of aviancommunities were analyzed and communities characteristic were compared between artificialreed wetland and natural reed wetland. Moreover, the impact of avian communities brought bythe reed reap was analyzed too. The main results conveyed as follows:1. Fifty bird species were recorded during the investigation and belonged to11order28families while29Passeriformes species were counted and comprised77.74%of the overallspecies with dominant numbers. Of all the species Resident bird and summer visitor comprisedabout66%with33species. The dynamic law of the avian density and species remained stableduring the year, the density and species reached its bottoms in January and February, then bounceback, the avian species reached its peak30in May and the avian density reached its peak14.74/ha in June. When it came to September, the density and species began to decline. October,November and December the avian density and species remain stable. The avian species,diversity and evenness exhibit obvious abundance in spring compared with other seasonsespecially winter, which showed lowest abundance in avian community.2. There were39and36kinds of bird species in artificial reed wetland and natural reedwetland respectively, from which25species were recorded in both habitats. The similaritycoefficient was0.625showing medium spatial heterogeneity. Passeriformes were frequentlyobserved in artificial reed wetland but seldom observed in natural reed wetland. However, thenumber of winter visitors, summer visitors, residents and migrant birds were not changeddynamically during the year. Avian species that recorded in artificial reed wetland were moreabundant than that of natural reed wetland in spring and winter but the opposite satiation wasobserved in summer and autumn. Contrast bird density of each month, from February to May, theartificial reed wetland>native reed wetland; from June to January native reed wetland in>artificial reed wetland. The two different reed habitats both had highest similarity coefficient of0.593in autumn and reached lowest similarity coefficient0.487in spring. The biodiversity ofnatural reed wetland was abundant in spring and summer, while the biodiversity of artificial reedwetland was abundant in autumn and winter.3. Investigation results were compared under three different temporal patterns, the monthbefore reed cutting, the reed cutting month, and the month after, in order to find the influence ofavian community due to reed cutting. This comparison revealed that ten avian speciesdisappeared in the cutting month but six more avian species were observed the month after.Passeriformes species were more sensitive towards reed cutting which rapidly decreased theavian community by50%. The highest similarity coefficient of the reed cutting month and afterwas0.647while the lowest similarity coefficient turned out to be0.423. The dynamic law of diversity index: the month after cutting>the month before> the cutting month, as well asevenness index: the month after cutting> the cutting month> the month before. After the cutting,new reeds began to grow in March. Reed height of rapid growth in May-July, the density of rapidgrowth in the March-May; reed density remained stable in June, reed height in July, continues togrow. The height of reed, artificial reed wetland greater than the native reed wetland, but reeddensity is low. T test found no significant difference (p>0.05).4. Spatial scales of avian community were different. Horizontal scale was divided into fourtypes: reed to land area, reed-inside area, reed to water area, water inside reed area. Avian specieswere distributed mostly in reed to water area and reed to land area which counted for60%and50%respectively. The avian numbers were mainly counted in reed-inside area and reed to landarea which counted for44.30%and30.70%. In vertical scale dimension reed vegetation weredivided into top, middle and bottom layer. The avian species in bottom layer comprised most ofthe vertical scale which counted as70%. The avian numbers were identified mainly in the middleand bottom layer of reed vegetation which counted for53.84%and34.75%respectively.According to the avian behavior recorded, we found that13avian species were closely relatedwith the reed vegetation. The reed cutting events in local area had brought a huge impact on theavian community, especially affected the avian density, winter visitor overwintering, and theforaging of specialized species. Based on the avian conservation principle, we recommended thatreed cutting action should adopted the methods conveyed as follows: proper retention of thewater area and reed area near waterside or just reap the top and middle layer of the reedvegetation.