Studies On The Bird Community In The Mangrove Region Located In The Coastal Areas In Fangcheng City

We did researches on the birds in mangrove reserve of Beilun estuary from July 2006 to January 2008. The followed five aspects were studied during this period: the bird community structure of different landscape in mangrove region, the mainly road in mangrove region effects on distribution of birds, the utilization to mangrove of the birds there, studies on foraging dynamic of three egrets in farmlands and studies on dominance of Little Egrets and Chinese Pond Heron.1. The mainly landscapes in the mangrove region were mangrove landscape, farmland landscape, forest landscape and the residential landscape. In December and January, the bird diversity of farmland landscape was proved to be maximum (Shannon-Wiener index = 2.931, evenness index = 0.742), while mangrove landscape to be minimum (Shannon-Wiener index = 2.403, evenness index = 0.647).The bird similarity of mangrove landscape and residential landscape was proved to be maximum (the correlation index is 66.67%), the similarity index of bird community composition of forest landscape and residential landscape is 65.52%. The bird communities in farmland landscape and residential landscape, farmland landscape and forest landscape were not similar, for their similarity indexes were all below 60%. In June and July, the bird diversity of forest landscape was proved to be maximum (Shannon-Wiener index = 2.931). The evenness index of residential landscape is the highest one. The similariy indexes of mangrove landscape and forest landscape was below 60%, while the indexes between any other landscapes were all more than 60%.2. There were 8 different transects located in different areas beside the mainly road. The distance of each nearby transect were the same. The results showed that: the total bird numbers and species presented a shape of "N". The transect which was 95m far from the road owned the most bird species and individuals, they were 20.33±6.66 and 3703.0±1247.8, while the transect 375m from the road owned the lest bird species and individuals, they were 5.00±1.73 and 224.0±126.2. The result (one-way variance analysis) showed that the bird individuals in transect 95m far from the road were significantly more than the individuals in other transects, and it's bird species were also significantly more than the species in these transects which were 235m-515m far from the road.3. We made a record of the resting individuals, the foraging individuals, the low flying individuals, the gaming individuals and meet frequency by investigating the birds appeared in mangrove. All the records above were the indexes to analyze the utilization to the mangrove of the birds there. The original data was analyzed by the way of factor analysis, and the results showed that all the indexes were highly scored in the first three principal components. So we say these five indexes were all very important in analyzing the utilization to the mangrove of the birds appeared there. 46 bird species were divided into different groups at the base of the five indexes by the way of poly-class analysis, and the results showed that 9 species (19.57% of total birds) belonged to the lowest utilization group, 8 species (17.39% of total birds) belonged to the less utilization group, 13 species (28.26% of total birds) belonged to the more utilization group, and 16 species (34.78% of total birds) belonged to the most utilization group.4. Studies on foraging dynamic of Chinese Pond Heron, Little Egret and Cattle Egret were conducted by the methods of instantaneous scanning sampling and focal-animal sampling at the National Nature Reserve of Beilun Estuary, Fangchenggang in Guangxi Zhuang Autonomous Region in spring and summer 2007. The results showed that the numbers of foraging individuals in every fixed time were different from each other, and all the numbers in every fixed time presented a shape of "U" in the daytime of every egret. The feeding time and of the foraging individuals of these three egrets in every fixed time were different from each other too. The difference between the numbers of foraging individuals, resting individuals in every fixed time, and the resting time of Chinese Pond Heron and Cattle Egret were very significant, the difference between the foraging time of these two egrets were significant. The difference between the foraging time and resting time of Chinese Pond Heron and Little Egret were significant. The difference between the numbers of foraging individuals, resting individuals in every fixed time of Little Egret and Cattle Egret were significant. All the differences above made these three egrets possible to live in the same place.5. We recorded 29 flocks with Little Egrets and Chinese Pond Heron during the research period. The individuals of Little Egret were about 35.1 and Chinese Pond Heron were about 2.6. The result by analyzing the appeared areas and the time for foraging, resting, vigilance of these two species showed that: the difference of Chinese Pond Heron in area selecting and the time for foraging when appeared with Little Egret or not were significant, while the difference of vigilance time were not significant. The correlation between Chinese Pond Heron individuals and Little Egret individuals was very significant, and their tome for foraging and vigilance were significant.Some factors which threatening the existence of the bird in mangrove region were concluded in this paper. Some important suggestions for protecting the bird there were also proposed in this paper, such as controlling the cultivation scale around the sea shore and properly deal with the deserted aquafarms et al.