云南省纳板河流域国家级自然保护区不同生境对外来入侵草本植物分布的影响

为探明外来入侵草本植物在不同生境中分布差异及关键影响因素,于2015年对云南省纳板河流域国家级自然保护区内天然林、天然林林缘、橡胶林、橡胶林林缘和农田5种生境共164个1 m2样方的外来入侵草本植物种类和数量进行调查,对比不同生境中外来入侵草本植物物种多样性的差异,运用主成分分析法分析5种生境中主要外来入侵草本植物群落组成及其与环境因子的关系。结果表明,5种生境中共发现外来入侵草本植物32种,其中橡胶林林缘和农田中外来入侵草本植物种类最多,达20余种,天然林中外来入侵草本植物最少,仅为6种。单因素方差分析结果表明,不同生境中外来入侵草本植物多样性指数差异显著。多重比较检验结果表明,天然林中外来入侵草本植物的物种丰富度指数、香农-威纳指数、辛普森指数和皮洛均匀度指数分别为0.50、0.15、0.09和0.16,均显著低于其它生境;橡胶林中外来入侵草本植物除均匀度指数外,其余多样性指数均显著高于天然林且显著低于其余3种生境;农田中外来入侵草本植物物种丰富度指数为5.50,显著高于其它生境。主成分分析结果表明,不同生境中外来入侵草本植物群落物种组成不同;本地乔灌木物种数量和海拔是影响外来入侵草本植物在不同生境分布的关键因子。

Effects of different habitats on distribution of invasive alien grasses in Nabanhe River Basin National Nature Reserve, Yunnan Province

To identify the variance of the distribution of invasive alien grasses and the influencing factors in different habitats, 164 subplots (1 m²) were investigated across five habitats, including natural forest, border of natural forest, rubber tree forest, border of rubber tree forest and farm, in Naban River Basin National Nature Reserve in 2015. Thirty-two invasive alien species were found in the five habitats, and more than 20 grasses were distributed on the border of rubber tree forest and farms. In contrast, only six species were found in natural forests. One-way ANOVA analysis results showed significant variance of diversity index among the five habitats. Based on least-significant difference analysis, species richness index (0.50), Shannon-Winner index (0.15), Simpson index (0.09) and Pielou evenness index (0.16) in natural forests were significantly lower than those in other habitats. Except for the eveness, the other indexes of invasive alien grasses in rubber forests were also significantly different from those in other habitats. The richness index of invasive alien grasses (5.50) in the farm was obviously higher than that in other habitats. The results of canonical correspondence analysis (CCA) showed that the species composition of invasive alien grasses were also different in the five habitats. CCA analysis implied that the distribution of invasive alien grasses was influenced by native tree and shrub richness and altitude.