Spatial heterogeneity of the seed bank at a peat lake in Australia

Abstract

Context In the face of global biodiversity decline, understanding the effects of potential climate change on the persistence of soil seed banks is critical, especially in wetland ecosystems. Although studies have explored the response of soil seed banks to changes in periodically inundated wetlands, little is understood about seed banks in peatlands. Aims We examined the spatial variability of soil seed banks during a recent drying event, the last of which occurred over 60 years ago. Methods We sampled the soil seed bank in three zones away from the centre of the dry lakebed at five depth intervals down to 50 cm. Key results Our study showed that the seed bank distribution in a peatland reflected the wetland plants examined at the time of the drying event. The distribution of seeds was along a flood gradient, suggesting an interaction between historical inundation intensity (Zone) and vertical (Depth) distribution of seeds, and correlated with the extant vegetation, as determined during a significant water drawdown period. Conclusions and implications This study shows that the ability of seeds to survive burial, either submerged or desiccated, even after long periods, may prove to have advantages for plant survival and establishment.