Shaanxi Hanjiang River Basin Winter Waterfowl Community Diversity And Distribution Patterns

A survey on community diversity, distribution pattern and number fluctuation of waterfowls in winter was conducted at Hanjiang River in Shaanxi province and then the protection suggestions were proposed. The main conclusions were as follows:1. The species composition of avian communityTotal of 48 species was recorded which belong to 33 genera,15 families and 8 orders. In which there are 42 non-passerine species and 6 passerine species, accounting for 87.50% and 12.50%, respectively. Among these species, there are 15 winter residents (31.25%) and 17 travelers (35.42%). There were 32 migrants and 16 residents, accounting for 66.67% and 33.33%, respectively. The dominant species included Mallard(Anas platyrhynchos) and Ruddy Shelduck (Tadorna ferruginea). The common species were Little Grebe (Tachbaptus ruficollis), Little Egret (Egretta garzetta), Spot-billed Duck(Anas poecilorhyncha), Green-winged Teal(Anas crecca),Common Goldeneye (Bucephala dangula). The rare species included 17 species such as Great "Cormorant (Phalacrocorax carbo) and Falcated teal (Anas falcata) and there was 18 accidents including Black-necked Grebe (Podiceps nigricollis), Intermediate Egret (Egretta intermedia), Herring Gull(Larus argentatus), etc. Crested Ibis (Nipponia nippon) which was listed as CITES Appendix I was national first-grade protected birds and Whooper Swan (Cygnus cygnus), Mandarin Duck(Aix galericulata) were national second-grade protected birds and 41 species were listed as "Three adsum species",29 species were recorded in Sino-Japanese Migratory Birds Protection Agreement and Sino-Australian Migratory Birds Protection Agreement.2. Comparison of avian community indexThere is an irregular variation in avian community diversity from upstream to downstream of Hanjiang River. The number of bird species was recorded as Han zhong =Yangxian>Xixiang>Chenggu>Shiquan=Ankang> Mianxian>Hanyin=Xunyang. The Shanon-Wianer index was recorded as Xixiang>Hanzhong>Chenggu> Yangxian>Shiquan>Ankang>Mianxian. The Simpson dominance index assumed Mianxian>Ankang>Shiquan>Yangxian>Chenggu>Hanzhong>Xixiang. The Pielou index was recorded as Xixiang>Mianxian>Hanzhong>Shiquan>Chenggu> Yangxian>Ankang. The species diversity of Xixiang, Han zhong, Chenggu and Yangxian was higher than that of other sites. The results showed the similarity index between Yangxian and Chengu County was highest (0.361), which shared 13 species. The similarity index between Yangxian and Hanzhong,Mianxian and Yangxian was the lowest (0.160).3. Distribution patternWader birds gathered in Yangxian, Hanzhong and Ankang. Comparing with many orders, there are more species and a large number throughout all the regions, the number of waterfowls accounted for 40.35%,33.76%,22.78% respectively; there are small species and scales of avian in Mianxian, Hanyin and Xunyang, accounted for 0.74%. resident birds are distributed around all regions, most distributed at Xixiang county. For winter birds, the big overlap appears through every region with similar composition. The overlap of travelers is less and different kinds confined to specific area. There are just 2 species of Podicipediformes, most of them distributed in Hanzhong city. The Great Cormorant is the only species of Pelecaniformes, mainly distributed at Chenggu county. There are 5 species of Ciconiiformes mostly presented in Yangxian and Hanzhong. The Anseriformes species with largest number presented a homogeneous distribution. Charadriiformes was only recorded at ShiQuan and upstream areas. The number of Coraciiformes species is low, mianly presented in Yangxian county. Passeriformes species was mainly distributed at Xixiang county.4. The number variationThe number of wader birds got the high peak in November and February respectively in total. Podicipediformes species presented an increasing trend from October to January, and got the top in January and then decline rapidly. Pelecaniformes species got the peak of number in November during one year. Ciconiiformes species appeared digressive trend from October to the following March. Anseriformes species was quite widely fluctuated among them, the number get the top in January. Charadriiformes species were always in a low level during a long period.5. Protection proposalsWater pollution, river channel sand mining and over-hunting were the main problems in wader birds protection in Hanjiang River. Thus, we suggested accordingly that Xixiang, Hanzhong, Chenggu, and Yangxian should be listed as protection areas in priority, and managements and public education should be strengthened.