桂西南峰丛洼地退化植被土壤种子库的初步研究

Preliminary study on soil seed banks of degraded karst vegetation in Southwest Guangxi

采用野外取样和盆栽试验观察相结合的方法，对桂西南不同演替阶段退化植被的土壤种子库进行初步研究。通过统计分析，其结果：（1）厚度为20cm的表层土壤的种子库密度，其值变动于0～1125粒·m^-2；（2）在物种丰富度和数量上占优势的种类均是草本植物，其中又以禾亚科、菊科的植物为主，灌木种类和数量较少，无乔木种类出现；（3）种子多集中在上层或接近上层，并且自上而下递减明显；（4）11月份采样的各演替阶段的种子库的物种丰富度和密度普遍比5月份相应演替阶段的高；（5）任两演替阶段的土壤种子库相似性较低，但出现在相邻的两个演替阶段相似性系数比相邻较远的两个演替阶段的相似性系数要高；（6）地上植被与土壤种子库的相关性不管在早期阶段还是中后期阶段都不紧密，而且从草丛阶段向乔灌林阶段演替，两者之间的相关性有降低的趋势。结果表明：对桂西南峰丛洼地退化植被，有必要开展人工诱导促进封山育林区植被恢复，从而构筑具有较高生态效益的生态防护林体系。

By the method of sampling in wild field combined with observing potted experiment,soil seed banks of karst degraded vegetation in different succession stages in Southwest Guangxi were studied. The results showed that.（1）Soil seed density at 0-20 cm depth layer was between 0- 1 125 seeds/m^2; （2）The dominant species both in richness and abundance were herbage which were dominated by Agrostidoideae family and Compositae family, the shrub species in richness and abundance were very low,and there were no tree speeies; （3） Most seeds distributed in the upper layer or near the upper layer, and the density decreased gradually from the upper layer soil to under-layer soil; （4）The richness and the density of the seed in every succession soil seed bank sampled in November were higher than that in May; （5）The comparability coefficient between any two succession stages were low, but the comparability coefficient in two contiguous stages were higher than that in discontinuous stages; （6）The seed relativity between soil seed banks and the ground vegetation were not tight,and the relativity decreased with the development from the herbosa stage to tree-shrub stage. The results suggest that, it is necessary to induce artificially to improve the restore of the vegetation for the degraded vegetation,thereby construct the ecological protective forests that have superior ecological benefits.