Aboveground Vegetation Influences Belowground Microeukaryotic Community in a Mangrove Nature Reserve

Over the last decades, invasion by the exotic cordgrass (Spartina alterniflora) has become one of the most serious and challenging environmental issues threatening mangrove wetland ecosystems in China. The purpose of the study was to investigate the microeukaryotic diversity and community composition after S. alterniflora invasion in a mangrove nature reserve and to elucidate the factors that are driving succession or shifts in microeukaryotic communities. In this study, the spatiotemporal distributions of microeukaryotic communities in coastal wetland sediments of the Jiulong River Estuary, southeast China were investigated. The microeukaryotic communities from the wetland were distributed within six major groups (i.e. Alveolata, Stramenopiles, Rhizaria, Viridiplantae, Fungi and Metazoa). Our results indicated that vegetation changes were the primary factor driving the shift in microeukaryotic community composition, rather than seasonal separation. Total nitrogen (TN) and oxidized nitrogen (nitrite and nitrate) were significant environmental factors in explaining the largest portion of the variation in microeukaryotic composition. The exotic cordgrass invasions affected the microeukaryotic communities and played a key role in shaping community structure. It appears that microeukaryotic community could be used as a bioindicator in assessing the recovery process of mangrove ecosystems.