中文摘要：

微生境对于脆弱生态系统的植被更新与恢复至关重要。为了探明侵蚀微环境对植物更新的影响,以黄土丘陵沟壑区裸坡为对照,选取细沟、浅沟沟坡、浅沟沟底3种侵蚀微环境,结合7种主要物种种子补播试验,通过2 a的萌发出苗、幼苗存活与生长监测,结果表明：除铁杆蒿幼苗存活率在裸坡高于各侵蚀微环境外,其他供试物种的种子萌发出苗率和存活率在细沟或浅沟环境明显高于裸坡,而且大部分植物种子萌发出苗率和幼苗存活率在细沟内最高;供试的7种物种幼苗的高度在裸坡不同程度地低于细沟、或浅沟沟底、或浅沟沟坡下,尤其在浅沟沟底的白羊草、长芒草和杠柳高度显著高于其他环境（P〈0.05）。各侵蚀微环境下,不同坡位对供试物种的种子萌发出苗率、幼苗存活率与高度的影响没有一致性规律。在黄土丘陵沟壑区,土壤侵蚀塑造的侵蚀微环境对大部分植物种子萌发出苗、幼苗存活和生长等更新关键过程具有一定的优势,其中,细沟更有利于植物种子萌发出苗及幼苗存活,而浅沟更有利于植物幼苗生长。然而,土壤侵蚀微地形对植物更新也存在一定的种间差异性,细沟和浅沟不利于种子极小的铁杆蒿种子萌发出苗及幼苗存活。合理管理与利用侵蚀微环境,对该区恶劣生境的植被恢复具有实际意义。

英文摘要：

Microenvironment is very important for vegetation regeneration in drought and fragile ecosystems. In this study,the rill,slope of shallow gully and inside of shallow gully were selected as the eroded microenvironments,and the bare slope as the control. The emergence,survival and height of 2-year-old seedlings were surveyed after seven main plant species were reseeded. The following results were obtained： The emergence and survival of seedlings of the studied species in rill or shallow gully were higher than those on bare slope,except the survival of Artemisia gmeliniion seedlings on bare slope was higher than in any other microenvironments. For most species,percentages of seedling emergence and seedling survival in rill were higher than in other eroded microenvironments. Seedling height of seven species on bare slope were shorter than in rill or on slope of shallow gully,or inside of shallow gully,especially the seedling height of Bothriochloa ischaemun,Stipa bungeana and Periploca sepium was significantly shorter on bare slope than in any other eroded microenvironment（ P〈0. 05）. For each eroded microenvironment,there was no uniform regularity for seedling emergence,survival and height among different slope positions（ P〉0. 05）. In conclusion,the eroded microenvironments benefited the key stages of plant regeneration,such as the seedling emergence,seedling survival and seedling growth. However,the effects of eroded microenvironments on plant regeneration performed differently among species. Rational utilization and management of microenvironments are of the realistic value for vegetation restoration in severe habitats.