青藏公路沿线植被多样性特征及其与环境因子的关系

青藏高原是全球气候变化的敏感区，青藏公路从北至南穿青藏高原而过，研究沿线植被物种多样性特征及其与环境因子的关系具有重要意义。本研究调查分析了沿线29个样点(从西宁市到拉萨市编号依次为1~29号)的植被群落学特征，并分析了它们同环境因子的关系。结果表明，青藏高原从北向南植被总盖度呈先降低后升高的趋势，其中7号样点(阿尔茨托山)最低；物种丰富度呈先降低后增加再降低的趋势，其中14号样点(风火山隧道)最低，26号样点(甲赤岗)最高；香农指数和辛普森指数随样点呈降低趋势；Pielou指数呈先降低后增加的趋势，其中22号样点(托青村)最低；Alatalo指数变化趋势与Pielou指数相反，但波动较大。对物种多样性指数和环境因子进行相关分析和逐步回归分析发现，物种盖度、物种丰富度和Pielou均匀度指数特征主要受水分因子控制，物种多样性指数(香农指数和辛普森指数) 与物种Alatalo均匀度指数特征与短波辐射关系密切。

Vegetation species diversity characteristics in relation to environmental factors along Qinghai Tibetan Highway

Qinghai Tibet Highway, a sensitive area to global climate change, passes through Tibetan Plateau from north to south. It is significantly important to study the characteristics of species diversity and its correlation to environmental factors along Qinghai Tibet Highway. The characteristics of the roadside plant communities and its correlation with environmental factors of 29 samples whose number was 1 to 29 from Xining to Lhasa along Qinghai Tibet Highway were investigated and analyzed. The results showed that the vegetation coverage of Tibetan Plateau decreased rapidly and then increased slowly from north to south, the lowest was sample plot 7 (AErCiTuoShan). The species richness firstly decreased and then increased, finally decreased rapidly, the lowest was sample plot 14 (Fenghuoshan Tunnel) and the highest was sample plot 26 (Jiachigang). The Shannon Wiener index and Simpson index showed a decreasing trend excluding several sample plots. However, the Pielou index decreased slowly and then increased rapidly, the lowest was sample plot 22 (Tuo Qing Village). The Alatalo index had an opposite trend but a large fluctuation with Pielou index. The correlation and stepwise regression analyses between species diversity and environmental factors suggested that species coverage, species richness and species evenness index (Pielou index) were positively influenced mainly by the water factors. The species diversity index (Shannon Weiner index and Simpson index) and species evenness index (Alatalo index) had a significant correlation to shortwave radiation.