Spatiotemporal Variation of Tidal Wetlands Affected by Human Activities during the Past 50 Years: A Case Study of Yueqing Bay in Eastern China

Abstract

Monitoring spatiotemporal changes in tidal wetlands under the disturbance of human activities provides a strong basis for coastal wetland protection and restoration. Long-term serial remote sensing images and other historical data were collected and analysed to investigate the distribution of tidal wetlands of Yueqing Bay in 1969, 1981, 1993, 2003, 2013, and 2021, a case study across the past 50 years. The data revealed that human activities cumulatively caused the net loss of approximately 59.62 km2 in area of tidal wetlands during the observation period. Firstly, between 1969 and 1993, reclamation primarily accounted for the variation of the tidal wetlands. Furthermore, between 1993 and 2013, the invasion of Spartina alterniflora and mudflat aquaculture also became important influencing factors. Between 2013 and 2021, development activities eased, and mangrove planting area increased. Over the analysis period, the overall results revealed that the tidal wetlands in Yueqing Bay underwent a transformation process from the relatively simple effects of exploitation by reclamation to the collective influence of combined exploitation and restoration, increasing the overall diversity of Yueqing Bay tidal wetlands over the study period.