河西走廊沙漠人工植被区土壤种子库特征

土壤种子库作为地上植被更新的重要的种源储备库，在植被自然恢复和演替过程以及生态系统建设中起着重要作用。以河西走廊不同区域沙漠人工植被为研究对象，研究了土壤种子库物种组成、时空分布和数量变化特征。结果表明：河西走廊沙漠人工林土壤种子库共出现27种植物，分属8科22属，以藜科植物最多，生活型以草本植物种子比例最高，占到90.6%—95.06%;土壤种子库密度介于19.29粒/m~2—858.57粒/m~2之间，从东到西呈水平地带性分布，土壤种子库分布主要集中在0—2cm土层中，不同样地土壤种子库密度均呈明显的垂直分布，在0—10cm土层内，随着土层深度增加，种子库密度先减小后增大；土壤种子库多样性(Simpson指数)在河西走廊东段沙漠人工植被区最高，在0.671—0.812之间，河西走廊中段沙漠人工植被区为0.417—0.809之间，河西走廊西段沙漠人工植被区为0.256—0.707之间，从东到西呈下降趋势，Shannon-Wiener指数、Margalett丰富度指数、Peilow均匀度指数也表现出相同的趋势，说明由于生境的植被的异质性程度高，使土壤种子库之间的差异性显著；河西走廊沙漠...

Analysis of soil seed bank characteristics of artificial revegetated desert area in Hexi Corridor

Soil seed bank, generally acknowledged as an important seed reserve for vegetation regeneration, plays an important role in the vegetation restoration and succession, as well as the ecosystems construction. The species composition, spatio-temporal distribution, and quantitative changes of re-vegetated desert areas in Hexi Corridor were investigated in this study. Results showed that there were 27 species of plants in the soil seed bank, belonging to 22 genera and 8 families, with the most common species in Chenopodiaceae. In terms of life-form, the seeds from herbs accounted for 90.6-95.06%. The density of soil seed bank was between 19.29-858.57 grains/m², showing a horizontal distribution pattern from east to west. The soil seed banks was mainly concentrated in the 0-2 cm soil layer in vertical direction. In the rang of 0-10 cm soil layer, there was an obvious vertical distribution pattern of seed density:with increase of soil depth, seed density first decreased then increased. Simpson Index in the soil seed bank was the highest in the re-vegetated areas of the east Hexi Corridor Desert (0.671-0.812), 0.417-0.809 of the middle Hexi Corridor Desert, and 0.256-0.707 of west Hexi Corridor Desert, with a downward trend from east to west. Shannon-Wiener Index, Margalett Richness Index and Peilow Evenness Index also showed the same trend. The large variation in species diversity indices among sites was most likely attributed by the high degree of inter-site vegetation heterogeneity. The similarity coefficients between soil seed bank and vegetation in the desert re-vegetated areas in Hexi Corridor were all below 0.45, indicating a significant difference in species composition. The soil seed bank was dominated by annual and perennial herbs, with a few shrubs, which indicated that the soil seed bank played a minor role in the regeneration and succession of the shrub layer in the desert re-vegetated ecosystems. This study proved that a sufficient amount of seeds in soil seed bank is an important foundation for the natural restoration of vegetation in desert, and advanced our understanding of the natural vegetation restoration in the re-vegetated desert areas.