Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Institute for Peat and Mire Research, Northeast Normal University, Changchun 130024, China.
Sci Total Environ. 2022 May 1;819:152035. doi: 10.1016/j.scitotenv.2021.152035. Epub 2021 Nov 29.
Soil salinization has become a widespread threat to the structure and ecological functioning of inland wetlands globally. Soil seed banks can be important for plant regeneration in salinizing wetlands. To explore the effects of soil salinization on soil seed banks and their potential role in revegetation, we studied the structure and composition of plant communities and soil seed banks along a soil salinization gradient, and analyzed the responses of Carex-dominated and Phragmites-dominated communities to saline-alkaline stress in the Songnen Plain, China. We found that the dominant species of aboveground vegetation were different along the soil salinization gradient. Carex spp. dominated in the non-salinized and mild salinity wetlands, and Phragmites australis dominated in wetlands with moderate and high levels of salinity. The species richness of aboveground vegetation, and the density and richness of soil seed banks were higher in wetlands with lower salinity. The structural equation model indicated that the difference in soil salinization was directly associated with the aboveground species richness, and density and richness of the soil seed banks, while it was indirectly associated with the density and richness of the soil seed banks by directly affecting the composition and the species richness of the aboveground vegetation. Soil seed banks in Phragmites communities were more tolerant of saline-alkaline stress than Carex communities. This study indicates that soil salinization affects the size and composition of soil seed banks and limits their role in plant regeneration in wetlands of the Songnen Plain. In addition to hydrological regulation, the reduction of soil salinity is necessary to protect and restore biodiversity in salinizing wetlands.
土壤盐渍化已成为全球内陆湿地结构和生态功能的广泛威胁。土壤种子库对于盐化湿地的植物再生可能非常重要。为了探讨土壤盐渍化对土壤种子库的影响及其在植被恢复中的潜在作用，我们沿着土壤盐渍化梯度研究了植物群落和土壤种子库的结构和组成，并分析了中国松嫩平原以薹草属和芦苇属为主的群落对盐碱性胁迫的响应。我们发现，地上植被的优势种沿土壤盐渍化梯度存在差异。薹草属在非盐化和轻度盐化湿地中占优势，而芦苇属在中度和高度盐化湿地中占优势。地上植被的物种丰富度，以及土壤种子库的密度和丰富度在低盐化湿地中较高。结构方程模型表明，土壤盐渍化的差异与地上物种丰富度、土壤种子库的密度和丰富度直接相关，而通过直接影响地上植被的组成和物种丰富度，土壤盐渍化与土壤种子库的密度和丰富度间接相关。芦苇群落的土壤种子库对盐碱性胁迫的耐受性强于薹草群落。本研究表明，土壤盐渍化会影响土壤种子库的大小和组成，并限制其在松嫩平原湿地植物再生中的作用。除了水文调节外，还需要减少土壤盐分以保护和恢复盐化湿地的生物多样性。
