Effects of Biological Soil Crusts on Seed Bank, Germination and Establishment of Two Annual Plant Species in the Tengger Desert (N China) |
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Authors: | Xin-Rong Li Xiao-Hong Jia Li-Qun Long Stefan Zerbe |
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Institution: | (1) Shapotou Desert Research and Experiment Station Cold and Arid Regions and Environmental & Engineering Research Institute, Chinese Academy of Sciences, 730000 Lanzhou, China;(2) Institute of Ecology, Technical University of Berlin, Rothenburgstr. 12, D-12165 Berlin, Germany |
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Abstract: | The presence of biological soil crusts can affect the germination and survival of vascular plants, but the reasons are not
well investigated. We have conducted a field investigation and greenhouse experiments to test the effect of crusts on two
desert annual plants, which occur on the stabilized dunes of the Tengger Desert in N China. The results showed that biological
soil crusts negatively influenced the seed bank of Eragrostis poaeoides and Bassia dasyphylla. The important effect of biological soil crusts on seed germination and establishment were performed indirectly through reducing
the amount of germinating seeds. Field investigation and experimental results with regard to the seed bank indicated that
higher seedling density was found in disturbed crust soil and bare soil surface than in intact crust soils. Greenhouse experiments
showed that the effects of biological soil crusts on germination and establishment of the two plants are not obvious in moist
condition, while disturbed crusts are more favorable to seed germination in dry treatment. Significant differences in biomass
were found between disturbed crust soil and bare soil. Survival and growth of the two annual plants were enhanced in both
algal and moss crusts during the season of rainfall or in moist environment, but crusts did not affect seedling survival in
the dry period. The small seeded E. poaeoides has higher germination than larger-seeded B. dasyphylla in crust soils, but B. dasyphylla has a relatively higher survival rate than E. poaeoides in crust soils. |
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Keywords: | Bassia dasyphylla biological soil crusts Eragrostis poaeoides establishment germination Tengger Desert |
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