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古尔班通古特沙漠地表广泛分布着生物土壤结皮,研究其覆盖下的土壤种子库,有利于了解生物土壤结皮的生态功能及当地植被更新与恢复的潜力。本文研究了该地区3种生物土壤结皮(藻结皮、地衣结皮、苔藓结皮)对土壤种子库分布特征和多样性的影响。结果表明:在种子库水平分布上,相比于裸沙,生物土壤结皮增加了种子库密度,且不同结皮类型对种子库的影响程度不同。地衣结皮土壤种子库的密度最大(5905±778粒·m~(-3)),其对种子的捕获作用最为明显,其次是苔藓结皮(1138±380粒·m~(-3)),藻结皮与裸沙无显著差异;水平分布上的差异与结皮的发育程度、种子的形态、不同生物土壤结皮空间分布的异质性有关。在垂直分布方面,结皮发育土壤,种子库集中分布在土壤浅层(0~2 cm),这与裸沙种子库的垂直分布特征基本一致,说明结皮的存在并没有显著改变种子库的垂直分布格局。此外,从裸沙到苔藓结皮,土壤种子库和地上植被的相似性不高(0.14~0.29),土壤种子库中的物种多样性和丰富度指数不及地上植被高。该研究区土壤种子库在植被恢复中的潜力可能较小,但相对于裸沙,生物土壤结皮的存在有益于土壤种子库的保持,对荒漠生态系统物种多样性的维持和稳定具有重要意义。
The biological soil crust is widely distributed on the Gurbantunggut desert surface and the soil seed bank covered by it is studied. It is beneficial to understand the ecological function of biological soil crust and the potential of local vegetation regeneration and recovery. In this paper, the effects of three kinds of biological soil crusts (algal crusts, lichen crusts and moss crusts) on the distribution characteristics and diversity of soil seed banks were studied. The results showed that in the horizontal distribution of seed bank, compared with bare sand, biological soil crust increased seed bank density, and different crust types had different effects on seed bank. The density of lichen crust soil seed bank was the highest (5905 ± 778 grains · m -3), which was the most obvious for seed seeding, followed by moss crust (1138 ± 380 grains · m -3) There was no significant difference between algal crust and bare sand. The differences in horizontal distribution were related to the development of crust, the morphology of seeds and the heterogeneity of the spatial distribution of different soil crusts. In terms of vertical distribution, the crusting development soil and seed bank concentrated in the shallow soil layer (0-2 cm), which was basically the same as the vertical distribution of bare sand seed bank, indicating that the existence of crust did not significantly change the seed bank Vertical distribution pattern. In addition, the similarity between the soil seed bank and the aboveground vegetation was not high (0.14 ~ 0.29), ranging from bare sand to moss crust. Species diversity and abundance index in soil seed bank were less than those in aboveground vegetation. The potential of soil seed bank in vegetation restoration in this study area may be small, but the existence of biological soil crust is beneficial to the preservation of soil seed bank relative to bare sand, which is of great significance to the maintenance and stability of species diversity in desert ecosystems .