西喜马拉雅地区气候变化与果蝇分布界限的移动

Climatic changes and shifting species boundaries of Drosophilids in the Western Himalaya

在长时间尺度上研究环境变化条件下的种群动态,有助于确定不同物种如何对新的生物和非生物条件做出反应。采纳类似的采集方法在相同的地点,分别于1961-1962年和2003-2004年在西喜马拉雅地区对果蝇种类进行了两次野外调查,对两次调查获得的种类的相对丰富度和优势度指数进行了比较。最近50年的气象数据显示西喜马拉雅平均气温(Tave)发生了显著变化,对该地区的果蝇种类组成及分布界限产生了影响。本研究发现在低海拔的地带Drosophila nepalensis及其他一些冷适应种类的数量明显下降;而Drosophila ananassae及其他一些暖适应种类则进入了低海拔和中海拔地带。D.nepalensis的丰富度与所调查地点的平均气温负相关(r=-0.93±0.03),而对于D.ananassaez则是相反趋势(r=0.90±0.05)。据此认为长期(42年)的气候变化已对西喜马拉雅地区的果蝇种类的分布格局产生了影响。

Population dynamics studies under shifting environmental conditions over a longer time scale can help to determine how different species react to new biotic and abiotic conditions.Two different field surveys with similar collection methods as well as sites in the western Himalayas（1961-1962 and 2003-2004）were compared on the basis of relative abundance and dominance indices of different Drosophila species.Climatic data for the last fifty years involves a significant change in average temperature（Tave）of western Himalayas,which has affected the distribution and boundaries of various Drosophilids in this region.Current study reports a significant decline in the number of Drosophila nepalensis and other cold adapted species from lower ranges;and introduction of Drosophila ananassae and other warm adapted species to lower and mid mountainous ranges.For D.nepalensis,species abundance is negatively correlated（r=-0.93±0.03）with Tave of the localities of origin and while reverse trend was observed for Drosophila ananassae（r=0.90±0.05）.Thus,climatic changes over long periods（42 years）have affected invasive ability of different Drosophila species in the western Himalayas.