关键词: 不同降雨年份, 封育, 补播, 施肥, 群落组成, 多样性, 生产力

Abstract: To explore the effects of restoration measures,such as enclosure,reseeding,and fertilization on desert grassland plant communities in both wet and dry years,a two-year manipulative experiment was conducted in desert grasslands of different degradation levels in Inner Mongolia. The results showed that in the severely degraded areas,enclosure significantly increased the density of forbs and the relative biomass of Stipa breviflora only in the wet year. Reseeding significantly increased the coverage of forbs,the density of the community and the density of grasses only in the wet year. Applying organic fertilizer significantly increased the coverage of the community and grass as well as the relative biomass of Stipa breviflora only in wet year. In the heavily desertified areas,reseeding significantly increased the density of community and grasses in wet year,and significantly decreased diversity index but increased aboveground biomass of community in dry year. In moderately degraded area,spraying foliar fertilizer significantly decreased coverage of community and forbs in wet year. Our results suggested that restoration measures had varying impacts on plant community characteristics in wet and dry years,and the same restoration measures yield different effects in grasslands with different types of degradation. The effectiveness of restoration measures can be ensured by selecting appropriate restoration measures according to local conditions,and the effects of inter-annual variations in precipitation on restoration outcomes should be fully considered.

Key words: Different rainfall years, Enclosure, Reseeding, Fertilization, Community composition, Diversity, Productivity