Roles of aboveground vegetation, soil properties, and disturbance in determining belowground bud bank in sand dune ecosystems

The processes whereby vegetation characteristics, soil properties, and disturbance events interact to determine the characteristics of plant bud bank are of considerable significance with respect to population recruitment and vegetation restoration in sand dune ecosystems. However, gaining an understanding of these processes represents a major challenge. In this study, we examined variations in the bud bank demographics of dune vegetation and the role of vegetation, soil properties, and disturbance in determining the size and composition of bud bank during the stabilization processes from active to fixed sand dunes. We investigated bud bank size and composition, vegetation characteristics, and soil properties in the interdune lowlands of active and fixed sand dunes in Inner Mongolia, China. We found that sand dune fixation increased bud bank density. Soil properties were determined to be the primary factors affecting bud bank in the interdune lowlands of an active dune, whereas vegetation density was the most important factor affecting bud bank in the interdune lowlands of a fixed sand dune. Among the different bud types, we found that rhizome and root-sprouting buds were dependent to a greater extent on soil moisture content in the interdune lowlands of active dunes, while in the interdune lowlands of fixed dunes, rhizome and root-sprouting buds had a greater dependence on soil total carbon. In contrast, tiller buds tended to be more related to vegetation density, whereas no evidence showed there was a prominent influence of any factor on collar buds. The mechanisms (vegetation, stress, and disturbance) affecting bud bank demographics are modified by sand dune fixation. The responses of different bud types to environmental factors differ in the interdune lowlands of both active and fixed sand dunes.