刈割对香根草护坡地植物群落早期特征的影响

Effects of Cutting on Early-stage Plant Community Characteristics of Slope Land Protected by Vetiveria zizanioides(L.) Nash

为科学构建和有效管理香根草（Vetiveria zizanioides（L.）Nash）护坡植物群落,尽早使其发挥生态功能,对不同刈割处理下建植初期的香根草护坡植物群落进行连续2年的定点调查与分析。结果表明：刈割增加植物群落中定居的物种数,且最先在群落中定居的主要为禾本科（Gramineae）、菊科（Compositae）和豆科类（Leguminosae）物种,3类物种数占物种总数的46.67%-77.78%;刈割能提高植物群落多样性指数和均匀度指数,并且表现出刈割频率高,群落丰富度指数高、群落优势度指数低的趋势。其中,2次/年刈割处理（4月上旬、6月上旬）总体表现最佳;植物群落中物种间的生态位重叠值随着香根草优势种群地位逐步提高而呈现下降趋势,但刈割会改变这种趋势;香根草在植物群落中起关键作用。香根草物种优势度与群落丰富度指数、群落优势度指数均呈显著线性正相关（P〈0.05）,而与群落均匀度指数呈极显著线性负相关（P〈0.05）。

In order to scientifically construct and effectively manage the slope-protection plant community of Vetiveria zizanioides （L.） Nash and make it perform its ecological functions as soon as possible, the effect of different cutting treatments on the early-stage plant community was studied for two years. Main results are described as follows： （1） Cutting increased the number of species in the community. At the early stage, the first resident plants in the slope-protection land were of Gramineae, Compositae and Leguminosae, counting 46.67 to 77.78% of the total species in the community. （2） Cutting increased the community diversity index and community evenness index, and the trend was that the higher the cutting frequency was, the higher the community richness index and the lower the community ecological dominance index were. Of all, the cutting treatment of twice per year （in the first ten days of both April and June） was the best. （3） Niche overlap values among plant species showed a declining trend along with the increase of V. zizanioides population dominance in the communities, but cutting changed the trend. （4） V. zizanioides played an important role in the communities. The species dominance of V. zizanioides population exhibited a significantly positive correlation （P〈0.05） with the community richness and community ecological dominance index, respectively, but a significantly negative correlation （P〈0. 01） with the community evenness index.