Winter And Spring Avian Communities In Southern Hongze Lake Wetland

Hongze Lake, which lies in the northwest of Jiangsu province, is the biggest wetland in the drainage area of Huai River and the fourth largest freshwater lake in china. It is especially important as a stop-over site for birds during south-north migration in china, and also a place where many waterfowls living in winter, but the research on the avian community of Hongze Lake has not been reported yet. In this research the avian fauna in 5 typical habitats (fish farm, watercourse, woodland, farmland and residential area) of Southern Hongze Lake Wetland was investigated during November to December 2005, March to May, October to December 2006, and March 2007. The bird species, abundance, spatial and temporal patterns and human disturbance on avian community were analyzed.1. There are 146 species of birds belonged to 85 genus, 43 families and 15 orders according to the investigation. The attributes of community structure in winter and spring such as species richness, density, dominant species, Shannon-wiener index, G-F index, species evenness, dominance, were compared and discussed. The results showed that the species richness in spring was higher than it in winter, but the density in winter was obviously higher than it in spring. Among different habitats, the fish farm had the highest species richness, the largest dominant species number, the greatest species evenness and Shannon-wiener index; while the residential area had the greatest density and G-F index; in winter, the species dominance in residential area was larger than the Others, while in spring the watercourse had the greatest.2. The birds of ardeidae, anatidae and shorebirds were predominant in population in the Southern Hongze Lake Wetland. The temporal species richness and amount variation of them were analyzed. The results showed that the species variation of anatidae and shorebirds was consistent with the amount variation of them; but the ardeidae's species richness and amount variations were different, the species number came to a head at the end of April, while the amount did at the end of December. In winter, the migration time was comparatively compact, centered on the period from the last ten days of November to the middle ten days of December, however, in spring there were two migration peaks: the anatidae's migration peak was in march and the shorebirds and the ardeidae's was at the end of April.3. The behavior of the dominant species and common species in different microhabitats in the fish pond in winter were analyzed. The result showed that the exposed muddy area and shallow water area were utilized by most of the waterfowls as refuges where they can feed or rest. So keeping a lower water level in fish farm can provide more forage and rest site for waterfowls in winter.4. Human disturbance was the main factor regulated the distribution of waterfowl. One hand, human activity in the study areas has produced 5 types of ecology edges so as to increase the diversity of the avian community; On the other hand, human activity such as, reed cutting, hunting and cultivating had caused habitat loss and fragmentation in wetland which made the species and number of waterfowls decrease obviously compared to that of the history records.5. Based on the above conclusions and wetland conditions, the existent problems of the southern Hongze lake wetland and the factors threatened the waterfowls had been discussed, and some reasonable management strategies for the conservation had been proposed.