Study On Community Structure Of Birds And Its Dynamic Change In DaLai Lake Nature Reserve Inner Mongolia

DaLai Lake National Nature Reserve of Inner Mongolia lies on the border among China, Mongolia, and Russia. It is one important member of the"Daurica international nature reserve"of China, Mongolia and Russia. It has been identified as"wetlands of International Importance". DaLai Lake is the fifth large fresh water lake in China, and it is the biggest lake in the north, at the same time it is the important passage way of the migration land birds in the east, playing an extremely important role on bird migration, reproduction of the northeast Asia birds in the course of achievement life cycle. Since the last ten years this area suffered drought all the time, and its water level descended ultimately, quality of water deteriorated, the area of water and wetland vegetation shrunk quickly.Little biological and ecological information is available about the birds in the region of DaLai Lake. Route investigation method was used to conduct statistical survey on bird community of reserve from August 2006 to August 2008, Shannon-Wiener index and G-F index were used to analyze the bird diversity, Remote Sensing image was quoted to analyze the change of habitat. Studies included the avifauna, diversity in different habitats, seasonal and annual dynamic of bird community, and which provided basic information in research of biology and ecology on birds study in this area. The main results were as follows:1. Analysis of avifauna:(1) 179 bird species were recorded in this survey, which belonged to 94 genera, 40 families and 18 orders. 37 species were the state key protection birds, of which 4 species were national first-grade protection bird, 33 species were national second-grade protection bird. 19 species were identified in"China Red Data Book of Endangered Animals". 40 species were identified in"CITES".12 species were identified in threatened bird of"IUCN". 94 species were identified in"protection agreement between China and Japan". 34 species were identified in"protection agreement between China and Australia".(2) Non-PASSERIFORMES are more than PASSERIFORMES in composition of birds. Non-PASSERIFORMES were mainly composed of Waterfowl. Migrants took a main proportion, and summer residents and travelers prevailed extremely. The palaearctic realm birds were the main types of avifauna, boreal taxa took a large proportion in the breeding birds, and avifauna had the mutual transitive character of Mongo-xinjiang region and Northeast region.2. Analysis of the birds'community diversity in different habitat and the habitat conservation priority: (1) Large lake with sedge was the main habitat of many waterfowl among 7 birds'habitats of reserve, in which they had stopped and reproduced, small non-sedge lake was an important habitat of staying and migrating to CHARADRIIFORMES,ANSERIFORMES and LARIFORMES, Wet meadow river was an important habitat of passing through in the early spring and late autumn to ANSERIFORMES. There were similar composition of PASSERIFORMES between Willow Shrub and Stone Cliff, but the latter was the key habitat to the distribution and reproduction of raptor. The formation of raptor in Stone cliff and grassland were very similar, but there were obvious difference in PASSERIFORMES. Bird community composition in seven habitats had their own character; any destruction on habitat would had a great influence on bird diversity.(2) Depending on richness, abundance, index of Shannon-Wiener and the quantity of state key protection birds, the results of prior conservation to different habitat and region indicated that: large lake with sedge habitat >small non-sedge lake habitat > lake beach with shallow water habitat>wet meadow river habitat; Stone cliff habitat>willow shrub habitat>grassland; Wulannuoer core area>Shuanmazhuang core area>Galadabaixin core area>Hulungou core area. Large lake with sedge and Wulannuoer core area centrally distributing in it were the prior conservation habitat and region; Stone cliff, small non-sedge habitat and Shuanmazhuang area centrally locating in them were also prior conservation habitat and region.3. Analysis of seasonal dynamic of waterfowl:(1) 92 kinds of waterfowl were recorded in this study, they were all summer residents or travelers. These species were richest in spring, there were 91 species, and its proportion in total was 98.91%. The second highest number appeared in autumn, there were 75 kinds of birds, and its ratio was 81.52%; the number was lowest in summer, 54 kinds of birds were recorded, and its ratio was 58.70%. There were apparent changes of waterfowl in different seasons of the same year.(2) The waterfowl in the reserve migrated in late March in spring, and the number rose quickly reaching the highest number in May, the migration would last to the late June. The kinds descended in July, and the quantities also descended. Migration begun in early August, and the migration of CHARADRIIFORMES and LARIFORMES centered in August, the migration of ANSERIFORMES centered in September and kinds of species reached the highest peak, the migration would last to late October.(3) Probably 26 species carried virus of bird flu in the reserve. There were 22 kinds of migrants and 4 kinds of residents among them. 18 species were the summer residents and 6 species were the travelers among migrants; 20 species were the waterfowl. Kinds reached the most in May and September. Common and a large number of migrants were Phalacrocorax carbo, Ardea cinerea, Platalea leucorodia, Anas Anser, Tadorna ferruginea, Tadorna tadorna, Anas acuta, Anas crecca, Anas platyrhynchos, Anas strepera, Anas clypeata, Aythya ferina, Fulica atra, Larus ridibundus.4. Analysis of anneal dynamic of waterfowl and change of habitat:(1) The species of waterfowl and G-F diversity index from high to low was as year 2000>year 2006>year 1987; the sequence of Galadabaixin core area was year 2000>year 1987>2006. There was no significant change of water level in reserve from 1987 to 2000. The quantity of waterfowl in 2000 was more than in 1987, because of increased area of wetland vegetation and numbers of lakes. Comparing to year 2000, shrink of water level in Dalai Lake, area on wetland vegetation and numbers on small lake in 2006 lead to significant decrease of waterfowl'number and species.(2) Change of habitat in Dalai Lake not only had influence on species and number of waterfowl, but also had influence on seasonal distribution of waterfowl, Ratio of summer residents decreased. However, ratio of traveler increased relatively.(3) There was high degree of dependence of Ardea cinerea, Botaurus stellaris, Platalea leucorodia, Grus grus, Grus monacha, Grus japonensis, Grus vipio and Grus leucogeranuson sedge marsh habitat, and the existence of sedge marsh habitat was directly related to their survival.