Study Of The Xi'an Bird Community Structure And Influencing Factors

The avian community in seven types of habitat in Xi'an city was surveyed from 2009 September to January 2011. The bird species, abundance, habitat chacters that influence urban bird communities were analyzed. Urbanization synthetical index was proposed as the index to exploring the quality of the urban ecological environment. The results are as follows:1. Avian communities in Xi'an urban area In total,181 species were recorded, which belong to 17 orders and 40 families. More than non-breeding species, the breeding birds(115) accounted for 63.5%. Among them, the number of residents, summer migrants, winter migrants, travelers and vagrant were 77,38,32,33 and 1, accounting for 42.5%,20.9%,17.7%,18.2% and 0.6% respectively. The species number of Passeriformes was the highest (98), accounting for 54.1% of total species. The Black Stork was national first-grade protected bird and fifteen of them were national second-grade protected birds.2. Seasonal variation of avian community. The research indicated a distinct change of bird species among seasons. The species number came to peak in spring (105) and autumn (123), summer (103) takes the second place and winter (98) is the last. The Shannon-Wiener and Pielou index subsequently reduced in spring, summer, autumn and winter. The Shannon-Wiener and Pielou index of the avian communities in woodland habitat were the maximum in spring, summer and autumn, and those of the woodland habitat avian communities were the minimum (4.6091). Species diversities of downtown were lowest in four seasons.3. Comparison on avian community among seven habitats. In the seven typical habitats, the sequence of species richness was:wetland> woodland> recent residential cropland> old residential>industrial>downtown, among which wetland and downtown contained 103 and 6 species, respectively. Density, species diversities and uniformity of avian community of wetland was the highest, and dominance of birds of downtown was the biggest. The sequence of density was:wetland> old residential>woodland> recent residential> cropland> downtown> industrial. The sequence of Shannon-Wiener index was:wetland> woodland> cropland> recent residential> old residential> industrial> downtown. The sequence of Pielou index was:wetland>woodland>industrial> cropland> downtown> recent residential> old residential. The sequence of similarity index was:downtown> old residential> industrial>recent residential>cropland> wetland> woodland. Based on CA(Cluster Analysis), the avian community could be divided into 3 group on the linkage of 5, the first group contained downtown, industrial, old residential and recent residential, the second group contained wetland and the third group included woodland and cropland.4. Influence of the habitat factors on avian community. In all habitats, there were significant positive correlation between bird species and green land coverage (R=0.852, P<0.01), negative correlation between bird species and human disturbance (R1=0.745, R.2=0.826, P<0.05). There were negative correlation between bird density and building index (R=0.782, P<0.05) and marked significant positive correlations between bird density and green coverage (R=0.706, P<0.01). There were marked significant positive correlations between diversities of bird species and green land coverage (R=0.706, P<0.01) and negative correlation between bird diversities of bird species and noise, human disturbance and building index (R1=0.735, R2=0.922, R3=0.782, P<0.05). There were significant positive correlation between evenness of avian community and building index and between evenness of avian community and human disturbance (R1=0.929, R2=0.794, R3=0.914, P<0.05). The research indicated that the main factors which influenced the distribution of birds were the building index and human disturbance and green land coverage.5. The influence of urbanization on avian community. The abundance and diversity of the avian community presented a downtrend along with the increase of urbanization. The bird density decreased with the increasing urbanization, and then rose with the degree of urbanization, final declined as the urbanization came to its peak.6. Suggestion to Xi'an avian protection. In accordance with the characteristics of Xi'an and above conclusions, based on the principles of wildlife conservation and conservation biology, advices are suggested to improve diversity of wildlife, especially birds.