【摘要】 为了探明高寒草甸土壤种子库对其沙化过程的响应,调查并分析了高寒区玛曲未沙化高寒草甸、沙化草地和流动沙丘土壤种子库特征与动态变化。结果表明:1)高寒草甸沙化过程中土壤种子库共出现物种13科32种,返青期和枯黄期均为11科24种,但物种组成有一定差异;2) 3种不同程度沙化草地0-15 cm土层种子库密度在返青期分别为3 096.0、679.4和56.6粒·m^-2,集中分布在0-5 cm土层,且种子库密度均随沙化程度增加而显著降低（P <0.05）,在枯黄期低于返青期,但差异不显著（P> 0.05）;3)无论是返青期还是枯黄期,高寒草甸土壤种子库物种的优势度、多样性、均匀度和丰富度指数均随沙化程度的增加而降低,典型高寒草甸一旦沙化,种子库物种多样性就会锐减;4) 3种不同程度沙化草地土壤种子库与地上植被的相似性均较低,在0～0.5,但枯黄期高于返青期。研究结果表明,土地沙化使得高寒区土壤种子库受损较大,高寒草甸一旦沙化其土壤种子库的数量和多样性就会锐减,地带性种群不宜生存而退出,自然恢复较为困难。因此,在高寒区沙化土地治理中,人工建立适宜的土壤种子库是有效恢复与重建草地植被的关键措施和途径。更多还原

【Abstract】 To understand the response of soil seed banks to grassland desertification in alpine regions, the characteristics and dynamic changes in soil seed banks located in non-desertified alpine meadows, sandy grasslands, and mobile dunes in Maqu alpine regions were investigated and analyzed. The results showed that: 1) 32 species belonging to 13 families appeared in the soil seed bank during the desertification process of alpine meadows, and 24 species from 11 families appeared during both the turning-green period and the withering period; however, the species composition was different. 2) The three grasslands had different degrees of desertification. The density of the seed bank in the 0 – 15 cm soil layer was 3 096.0,679.4, and 56.6 grains·m-2 in the greening stage, concentrated in the 0 – 5 cm soil layer, and the seed bank density decreased significantly as the degree of desertification increased(P < 0.05). The density during the yellowing period was lower than that during the turning-green period however, the difference was not significant(P > 0.05). 3) For both the greening period and the yellowing period, the degree of species dominance, diversity, uniformity, and abundance in the soil seed bank in the alpine meadow decreased with increasing degree of desertification. Once the typical alpine meadow was desertified, the species diversity of the seed bank noticeably decreased. 4) The similarity between the soil seed banks of the three grasslands with different desertification degrees and their vegetation was low, between 0 and 0.5; however, the similarity during the yellowing period was higher than that during the turning-green period. The results showed that the soil seed bank could be significant for the restoration of alpine desertified grassland. During the rejuvenation period, different types of degraded grasslands can be supplemented with common species or break seed dormancy to achieve vegetation restoration. Land desertification had a clear influence on the destruction of soil seed banks in alpine pastures. The density and diversity of soil seed banks decreased rapidly, zonal vegetation disappeared from the communities, and vegetation restoration became increasingly difficult. Therefore, it was an effective measure for vegetation restoration and reconstruction in alpine meadow areas to establish a scientific artificial soil seed bank.更多还原