Effects of biological soil crusts on soil seed bank and seed germination of desert plants in North China
生物土壤结皮对荒漠土壤种子库和种子萌发的影响

We investigated the influences of algae crust and moss crust universally spreading in southeast of the Tengger Desert with four developing phrases (24-, 41-, 50-year-old crusts in the sand-binding vegetation areas and crusts in natural vegetation) on desert plants. Variable treatments (natural field condition, greenhouse and shadow) were assigned, and two soil moisture regimes were designed to investigate how desert plants responded under different moisture regimes of crusts. Our results showed that seed bank storage was significantly higher in moss crust than in algae crust. With the development of crusts, seed bank storage increased in moss crust while decreased in algae crust. With regard to the moisture, Significant differences in crust moisture were found among four developing phases for both algae and moss crust (p<0.05). The higher moisture kept in crusts, the more seedlings occurred. However, crust surface temperature and subsurface temperature did not have significant effects on seed germination for both crusts (p>0.05). For moss crust, more seed germination occurred under higher surface temperature, contrarily, more seed germination occurred under lower temperature on algae crust.