In gypsum soil communities, above-ground vegetation and seed banks are tightly connected, but mechanisms involved in their organization may differ. Peralta et al. investigated the effects of water addition, biological soil crust cover (BSC), above-ground vegetation and the Stipa tenacissima tussocks on soil seed banks at two spatial scales.
BSC has a filtering role at fine spatial scale on seed bank structure: it decreased seed abundance and species richness in the persistent seed bank, and it determined complete seed bank species composition. The heterogeneity of BSCs promotes niche differentiation and thereby potentially enhances species coexistence and species diversity.
Ana María López Peralta, Ana María Sánchez, Arantzazu L. Luzuriaga, Adrián Escudero, 2016, 'Factors driving species assemblage in Mediterranean soil seed banks: from the large to the fine scale', Annals of Botany, vol. 117, no. 7, pp. 1221-1228 http://dx.doi.org/10.1093/aob/mcw039