Changes and determinants of belowground bud banks along an interdune lowland sequence

Abstract

Understanding the changes and determinants of the belowground bud bank density of different plant functional groups along an interdune lowland sequence is essential for the exploration of community structure and vegetation restoration in sand dune ecosystems. However, how bud banks of different plant groups change and what are the regulating factors are still not clear, especially for the degraded ecosystems such as sand dune fields in desertified grasslands. In Horqin Sandy Land, Northeastern Inner Mongolia, China, we measured the bud bank densities of different plant functional groups (grasses, sedges and forbs) and biotic and abiotic parameters relevant to bud banks in five interdune lowlands differing in area and shape. Belowground bud bank densities of different plant functional groups varied with increasing interdune lowland area. Plant density had direct positive effects, but the area and shape of interdune lowlands had an indirect effect on bud bank density. The bud bank density was significantly smaller for the graminoid plants but increased for non-sedge forbs in the large interdune lowland compared to the smaller ones. Water stress and interdune lowland features exerted strong indirect effects on bud bank density. These findings suggest that plant conservation programs in active dune ecosystems should consider the joint effects of plant density, water regime, and interdune lowland area and shape on bud bank density for different plant functional groups.