Response of forest bird communities to forest gap in winter in southwestern China

Although forest gap ecology is an important field of study, research remains limited. By plot setting and point counted observation, the response of birds to forest gaps in winter as well as bird distribution patterns in forest gaps and intact canopies were studied in a north tropical monsoon forest of southwestern China from November 2011 to February 2012 in the Fangcheng Golden Camellia National Nature Reserve, Guangxi. The regression equation of bird species diversity to habitat factor was Y₁=0.611+0.002 X₁₃+0.043 X₂+0.002 X₅−0.003 X₈+0.006 X₁₀+0.008 X₁ and the regression equation of bird species dominance index to habitat factor was Y₃=0.533+0.001 X₁₃+0.019 X₂+0.002 X₃−0.017 X₄+0.002 X₁. There were 45 bird species (2 orders and 13 families) recorded in the forest gap, accounting for 84.9% of all birds (n=45), with an average of 9.6 species (range: 2−22). Thirty-nine bird species (5 orders and 14 families) were recorded in non-gap areas, accounting for 73.6% of all birds (n=39), with an average of 5.3 species (range: 1−12). These results suggested that gap size, arbor average height (10m from gap margin), arbor quantity (10m from gap margin), shrub quantity (10m from gap margin), herbal average coverage (1m from gap margin) and bare land ratio were the key forest gap factors that influenced bird diversities. On the whole, bird diversity in the forest gap was greater than in the intact canopy. Spatial distributions in the forest gaps were also observed in the bird community. Most birds foraged in the “middle” and “canopy” layers in the vertical stratification. In addition, “nearly from” and “close from” contained more birds in relation to horizontal stratification. Feeding niche differentiation was suggested as the main reason for these distribution patterns.

Keywords
Forest gap; Bird diversity; Spatial distribution; Trophic distribution; Forest