Effect of biological soil crusts (BSCs) composition on early establishment of vascular plants in eroded soils

Abstract

Biological soil crusts (BSCs), composed of lichens and bryophytes among the most conspicuous organisms, colonize and stabilize eroded soils, provide nutrients and interact with vascular plants. The effect of BSCs on germination and early establishment of plants is far from being fully understood. The relationship between BSC composition and vascular plants has been found to be species-specific. In this study, we evaluated how BSC composition affects germination and early establishment in two species of vascular plants (Jarava juncoides and Noticastrum marginatum) present in eroded areas of the Sierras Grandes de Córdoba, central Argentina. We conducted a laboratory experiment that consisted of sowing seeds of the two plant species on different types of BSC cover: Diploschistes spp. (crustose lichens), Xanthoparmelia spp. (foliose lichens), Cladonia spp. (fruticose lichens), Polytrichum sp. (bryophytes), and bare soil as control treatment. We recorded the number of germinated seeds and of established seedlings for two months. Bryophytes and lichens did not facilitate seed germination in the controlled environment; however, early establishment was not affected by the treatments. The interaction between BSCs and germination and early establishment of the studied vascular plants was found to depend on the dominant composition of the BSCs and the plant species.

Key words:
cryptogams; Jarava juncoides; lichens; mosses; Noticastrum marginatum