塔里木河下游不同地下水位下土壤种子库特征

Characteristics of soil seed bank in the regions with different groundwater levels in lower reaches of Tarim River

选取塔里木河下游不同地下水位的25个天然植物群落样地,进行土壤种子库取样,通过萌发试验分析不同地下水位条件下土壤种子库的密度、物种多样性、生活型比例及土壤种子库与植物群落的相似性等特征。结果表明,在干旱地区,地下水位的高低不仅影响植物群落的种类和组成,而且也影响土壤种子库的密度和组成。随着地下水位的逐渐下降,植物群落退化程度的加重也反映到种子库上,表现为种子库密度减少、物种多样性下降、生活型逐渐单一,同时植物群落与土壤种子库的相似性系数也逐渐降低。该研究有助于丰富干旱区土壤种子库的理论和指导塔里木河下游的生态恢复实践。

Twenty-five natural vegetation plots with different groundwater levels in the lower reaches of Tarim River were selected, and their soil seed bank density, plant species diversity, lifeform proportion, and similarity between plant communities and soil seed bank were studied by using seed-emergence method. The results showed that in arid regions, groundwater level not only affected the species and composition of plant communities, but also affected the density and composition of soil seed bank. With decreasing groundwater level, the degradation of plant communities also reflected on the changes of soil seed bank, e. g. , the decreases of soil seed bank density and plant species diversity, the simplification of life-form, and the decrease of the similarity coefficient between plant communities and soil seed bank. This study could help to the enrichment of theoretical knowledge of soil seed bank in arid regions, and also, the practice of ecological restoration in the lower reaches of Tarim River.