贵州北盘江喀斯特地区车桑子造林对乡土植物物种多样性的影响

为明确车桑子(Dodonaea viscosa)造林对北盘江喀斯特地区乡土植物物种多样性的影响,该研究采用群落样地调查法对不同车桑子覆盖度(0、20%、40%、60%、80%、100%)下的植物群落进行实地调查,并对其植物群落的物种多样性进行了对比分析。结果表明:(1)随车桑子覆盖度的增加,群落物种数及高位芽物种数有所下降,留下的物种多为地面芽、隐芽和一年生的草本植物。(2)随车桑子覆盖度的增加,Margalef指数、Simpson指数、Shan-non-Wiener指数及Pielou指数均呈下降趋势,群落中植物的种类和数量均减少,群落结构趋于简单,稳定性降低。(3)随车桑子覆盖度的增加,群落的物种组成不断发生替换,且草本植物的物种替代率均大于木本植物,但群落中物种间替代率呈先降低后升高的趋势,相邻两覆盖度之间的物种相似性系数呈先增加后减小的趋势。研究认为,当车桑子覆盖度≥60%后,乡土植物物种丰富度、多样性相对较低,物种分配不均匀,群落结构变简单,稳定性较差,不利于群落向更高级的演替阶段发展。

Effect of Afforestation of Dodonaea viscosa on Native Plant Species Diversity in Karst Area of Beipan River of Guizhou

In order to clarify the effect of afforestation of Dodonaea viscosa on the native plant species diversity in karst area of Beipan River, we are adopting the community sample survey method to investigate the plant communities under different D. viscosa coverages (0, 20%, 40%, 60%, 80% and 100%), comparing and analyzing the species diversity of the plant communities. The results are as follows: (1) with the increase of D. viscosa coverage, the number of species in the community and phanerophytes slightly decrease, and the remaining species are mostly herbage of hemicryptophyte, cryptophyte and therophyte. (2) With the increase of D. viscosa coverage, Margalef index, Simpson index, Shannon wiener index and Pielou index all showed a downward trend, the plant species and quantity decrease, the community structure tend to be simple and the stability decrease. (3) With the increase of D. viscosa coverage, the species composition of the community is constantly replaced, and the species substitution rate of herbaceous plants is higher than that of woody plants. However, the variation trend of substitution rate among community species first decreased and then increased, while the species similarity coefficient between adjacent two coverings (0% and 20%, 20% and 40%, 40% and 60%, 60% and 80%, and 80% and 100%) first increased and then decreased. The results showed that when the D. viscosa coverage reaches 60% or higher, the local plant species richness and diversity are relatively low, the species distribution is uneven, the community structure become simple and the stability is poor, which is not good for the community to develop to a higher stage.