Spatial variability of soil seed banks in the active sand dune systems in semi-arid region, China

摘要

The soil seed banks may provide a mechanistic understanding of recruitment dynamics and inform conservation management for the ecosystems.To assess the potential contribution of soil seed banks to vegetation restoration in active sand dune systems,comparisons of average seed density and similarity between soil seed bank and standing vegetation among active sand dunes,ecotones and interdune lowlands were made in Horqin Sandy Land,China.The results showed that average seed density in interdune lowlands was larger than ecotones and active sand dunes.The seed density in the soil layer of 0-10 cm was greater than 10-20 cm both in the active sand dunes and the ecotones,but there was no significant difference between the layer of 10-20 cm and 20-30 cm in the active sand dunes.Moreover,the spatial autocorrelation of the seed density on the active sand dunes was week,whereas strong on the ectones and interdune lowlands.Compositional similarity between soil seed bank and the standing vegetation was greater in the ecotones than the active sand dunes,but not higher than the interdune lowlands.Consequently,vegetation restoration can nott mainly rely on the soil seed bank on the active sand dunes,and more attention should paid to the interdune lowlands protection because they are the main source of seed dispersal and seedlings recruitment in active sand dune systems.