喀斯特山地典型植被恢复过程中土壤种子库特征

Features of Soil Seed Bank in Karst Mountain during Typical Vegetation Restoration

用"以空间换时间"的方法,从种类组成、种子数量、物种多样性、种子分布规律和物种相似性等方面比较了喀斯特山地典型植被恢复过程中处于不同生态演替序列的坡耕地、1年弃耕地、灌草地、15年疏林地、25年次生林地的土壤种子库特点。结果表明,研究区典型植被恢复过程中的5个样地土壤种子库共萌发植物46种,土壤种子库组成总体上以草本植物为主且与地上植被关系较密切,并仍处于植被演替的早期阶段,退化较严重;随着土地利用强度的增加,土壤中草本种子所占的比例也越大;石灰岩草坡开垦成耕地后,本来较小的种子库很快受到破坏。土地利用方式的变化是对岩溶山地次生植被及其种子库的主要威胁。

Using the method of ＂replacing time by space＂,the properties of soil seed banks of typical vegetations in different ecological evolution sequence in karst mountain（25-year woodland,15-year scattered woodland,bush-grass land,1-year abandoned farmland and slope farmland） were studied based on the analysis of species composition,amount and distribution,ecological dominance,species similarity as well as diversity.46 species germinated in 5 soil seed banks.Herbage species were dominant in soil seed banks;and the formation of seed banks had a close relation with vegetations,which indicated that the vegetations were at the early stages of succession and depredated seriously.The seeds amount of xylophyta species decreased while that of herbaceous species increased with the increase of land use intensity.The species of cosmopolitan contributed to big percentage in shrub-grass plots soil seed bank indicating that the growth of herbaceous layer was affected significantly by human beings activities.After the karst slope being cultivated,its soil seed banks might be destroyed soon.Therefore,the changes of land use pattern were the main threat to the karst secondary vegetation and the soil seed banks.