太白山是秦岭山脉的主峰, 生物区系成分复杂。为了研究太白山鸟类区系在过去20年间的变化, 我们于2007年5-7月(夏季)和9-10月(秋季), 根据海拔和典型植被在太白山南坡选定5种生境类型(退耕林、阔叶林、混交林、针叶林和高山灌丛草甸), 并在各种生境中选择样区采用样线法对鸟类组成进行调查。两个季节共观察到鸟类122种, 其中留鸟85种, 夏候鸟31种, 冬候鸟1种, 旅鸟5种。不同的生境类型中优势种和常见种不同, 而且在夏秋两季也有变化。中低海拔退耕林带鸟类物种数最多, 夏季有60种, 优势种为绿背山雀(Parus monticolus)、黄腹山雀(P. venustulus)和冠纹柳莺(Phylloscopus reguloides); 秋季有59种, 优势种为大山雀(Parus major)。中海拔阔叶林带夏季有鸟类40种, 优势种为绿背山雀、黄腹山雀和异色树莺(Cettia flavolivaceus); 秋季37种, 优势种是黄腹山雀、黑冠山雀(Parus rubidiventris)和银脸长尾山雀(Aegithalos fuliginosus)。 中高海拔针阔混交林带夏季有46种, 优势种是黄腰柳莺(Phylloscopus proregulus)、极北柳莺(P. borealis)和黑冠山雀; 秋季有37种, 优势种是黑冠山雀、褐冠山雀(Parus dichrous)和长尾山椒鸟(Pericrocotus ethologus)。高海拔针叶林带夏季有36种, 优势种是黄腰柳莺和黑冠山雀; 秋季有27种, 优势种是血雉(Ithaginis cruentus)和黑冠山雀。高山灌丛草甸带物种最少, 夏秋季都只有7种。各生境中鸟类物种组成的季节周转率随着海拔的升高而下降, 物种丰富度也呈现同样的趋势。太白山南北坡鸟类物种组成有较高的相似性。与20年前相比, 尽管在每种生境类型中优势种和常见种的组成仍相似, 但太白山南北坡的鸟类物种组成有较大的变化。

Taibai Mountain, located in southwestern Shaanxi, is a major summit in the Qinling Mountains of central China. To analyze changes to its avifauna over the past 20 years, we performed bird surveys from May to July (summer) and from September to October (autumn) in 2007 on the south slope of Taibai Mountain. Based on elevation and vegetation, five habitat types were categorized (afforested area, broadleaved forest, broadleaved coniferous mixed forest, coniferous forest, and alpine meadow), and characteristic sample area were selected within each habitat type. Birds were counted in each sample area using line transects. The relative density of species was calculated and ranked based on the relative abundance and estimated area, and dominant and common bird species in each habitat type were defined according to ranks of species density. We recorded a total of 122 bird species, including 85 residents, 31 summer breeding migrant, 1 winter migrant and 5 passing migrant. Species richness, relative abundance, and identity of dominant and common species varied across habitat types. Even within a given habitat type, bird species diversity and the identity of dominant and common species exhibited obvious seasonal changes. In the afforested area, 60 species were recorded in summer, of which two tits Parus monticolus and P. venustulus and a warbler Phylloscopus reguloides were dominant species. In autumn 59 species were recorded, of which the tit Parus major was dominant. In the broadleaved forest, 40 species were recorded in summer of which the tits Parus monticolus, P. venustulus and the warbler Cettia flavolivaceus dominated, and 37 species were recorded in autumn with the tits Parus venustulus, P. rubidiventris and Aegithalos fuliginosus being dominant. In the broadleaved coniferous mixed forest, 46 species were recorded in summer of which the warblers Phylloscopus borealis, P. proregulus and the tit Parus rubidiventris were dominant, and 37 species were recorded in autumn with the minivet Pericrocotus ethologus, the tits Parus dichrous and P. rubidiventris dominating. In the coniferous forest, 36 species were recorded in summer with the warbler Phylloscopus proregulus and the tit P. rubidiventris being dominant and 27 species were recorded in autumn of which the tit P. rubidiventris and the pheasant Ithaginis cruentus were dominant. In alpine meadows, 7 species were recorded in summer and 7 species in autumn. Species seasonal turnover rates and bird species richness decreased with increasing elevation. Bird species diversity was highly similar between the north and south slope. Based on the comparison between current and historical data, our results indicate obvious changes of bird diversity on Taibai Mountain in 20 years, though the composition of dominant and common species in each habitat is similar.