The Research Of Bird Communities Structure With Different Grazing Intensity In Grassland Of Honghua'erji In Inner Mongolia

From July to June in 2005 and 2006, the bird community structures were investigated in grasslands with different grazing intensities in Honghua'erji area of Inner Mongolia. 32 quadrats were investigated in the selected regions with quadrat method, in the time of 4:00～9:00 am and 3:00～6:00 pm.A total of 39 species of birds was recorded, which falls into 8 orders and 18 families. Passeriformes, Falconiformes, Anseriformes, Charadriiformes, Ciconiiformes, Galliformes, Columbiformes and Cuculiformes were 27, 4, 2, 2, 1, 1, 1 and 1 species of all, respectively. Based on flora, it included 31 palaearctic species and 8 cosmopolitan species, which accounted for 79.49% and 20.51%.The bird diversity indexes and the densities variety tend were consistent in the 4 different grasslands of no grazing, light grazing, medium grazing and heavy grazing. The bird diversity indexes increased as grazing intensity went up in the 3 former grasslands, and reached to the maximum at medium grazing intensity of 2.224, light grazing intensity of 1.856, no grazing of 1.642, and minimum at heavy grazing intensity of 0.884. While equality indexes reduced as grazing intensity went up and reached to the minimum at heavy grazing intensity.The relevance of grass height and covering degree were not remarkable with the birds diversity, the birds species and the birds densities in the 4 different grasslands, while which were remarkable with the birds densities of Coturnix cot-urn& (r₁=0.976, r₂=0.953),Corvus corone (r₁=-0.961, r₂=-0.983)and Oenanthe isabellina (r₁=-0.958, r₂=-0.982); The relevance of vegetation species were remarkable with the birds diversity (r=0.926, P＜0.1), the birds densities (r=0.985, P＜0.05 ) and the birds species (r=0.996, P＜0.05), the regression equation were y=0.094x+0.464 (R²=0.857), y=0.248x-0.542 (R²=0.969) and y=2.018x-8.485 (R²=0.993), respectively. Which were also remarkable with the birds species of Melanocorypha mongolica (r=0.993, P＜0.01),Emberiza spodocephala (r=0.967, P＜0.05) and Emberizafucata (r=0.976, P＜0.05)。...