Current situation investigation and invasion process analysis of Spartina alterniflora in marine reserve

Based on the investigation results of Spartina alterniflora invasion area and potential invasion area (control area) in Quanzhou bay and Zhangjiang estuary in 2019, this paper analyzes the growth status, sediment environment and intertidal benthic community of Spartina alterniflora in different invasion areas, and analyzes the invasion process of Spartina alterniflora in combination with historical remote sensing image data. The results show that: (1) Spartina alterniflora in Zhangjiang estuary is in a period of rapid expansion, The high tide area of Spartina alterniflora and mangrove compete with each other in the study area, which makes it more inclined to expand to the light beach; Spartina alterniflora is distributed in patches in Quanzhou bay. After 2018, the expansion rate has decreased and is in a stable expansion period. (2) Compared with the control area, the sediment environment of Spartina alterniflora invasion area shows the characteristics of low Eh and high contents of total phosphorus, total nitrogen, sulfide and organic matter. The total salt content and sulfide may be different due to different expansion periods. (3) The species number and habitat density of intertidal benthos in the invasion area of the two study areas are lower than those in the control area. The intertidal benthos community in the invasion area of Spartina alterniflora in Zhangjiang estuary is more disturbed, which may be related to the high content of sulfide in the sediment environment. (4) When formulating the management policy of the reserve, we should avoid the sports action of beach retirement, and pay attention to the management and protection effect of the reserve after beach retirement. The results can provide a scientific basis for predicting the potential distribution area of Spartina alterniflora and provide important information for the scientific management and control of nature reserves.