Characteristics of soil seed bank and their correlations with soil factors in the early restoration period of Populus deltoides cutting slash in Lake South Dongting, China.

Abstract

To understand the potential role of soil seed bank in natural vegetation restoration of Populus deltoides cutting slash in Lake Dongting, the structure and diversity of soil seed bank and its relationship with vegetation and soil parameters were observed and analyzed on the lake beach in the first two years after P. deltoides cutting, with P. deltoides lake beach as control (CK). A total of 65 plant species germinated in soil seed bank, belonging to 59 genera and 23 families. The density of soil seed bank and number of species ranked as 1-year cutting slash (11810 seeds·m-2, 49 species)> 2-year cutting slash (9686 seeds·m-2, 44 species)> CK (6735 seeds·m-2, 29 species). Compared with CK, species diversity of the perennial mesophytes and hygrophytes in the soil seed bank and aboveground vegetation of cutting slash, as well as the similarity coefficient between soil seed bank and aboveground vegetation, increased. Soil water content and nutrient content increased, while the pH decreased. Soil water content and organic matter were closely related to the distribution of hydrophytes such as Polygonum hydropiper, while total potassium and phosphorus contents had a greater influence on the distribution of perennial species such as Phalaris arundinacea. In summary, during the natural restoration of P. deltoides cutting slash in Lake Dongting, with the changes of soil physicochemical properties, species richness and density of soil seed bank increased significantly, and the diversity of aboveground vegetation species therefore increased. Soil seed bank is an important propagule source for the restoration of wetland vegetation in cutting slash.