Abstract: Coastal wetlands are unique ecosystems formed by amphibious mutual effects. Human activities severely affect wetland evolution. Since the 1950s, China has experienced a massive sea reclamation, which resulted in extremely rapid degradation and loss of coastal wetlands. Studies on the evolution of coastal wetlands and its correlation with human activities are of great significance for managing and protecting wetland resources. The spatialtemporal evolution characteristics of coastal wetlands under the influence of sea reclamation were examined based on the TMremote sensing images in four years (1985, 1995, 2005, and 2015). The transfer matrix of land use and approach of landscape pattern analysis were used in this study. These data were analyzed by 3S technology and the software of eCognition 9.0, and FRAGSTATS 4.2. The results showed that the hotspots of changes in coastal wetlands were Yellow River Delta, Laizhou Bay, Bohai Bay and Liaohe River Delta. The natural wetland area decreased by 45.37%, whereas the artificial wetlands expanded by 57.23% in the past 30 years. Aquatic farm and salt field increased most significantly, which were mainly changed from moor and intertidal zone. Natural wetlands were converted into artificial ones, and artificial wetlands were converted into non-wetlands. Natural wetlands became more artificial. The landscape pattern tended to be fragmented and equilibrated. Meanwhile, the landscape heterogeneity decreased due to the strong human disturbance. Sea reclamation occupied a large area of natural wetlands such as moor and intertidal zone, with an increment of 1606.79 km² in the past 30 years. The main land use types were aquatic farm and construction land. The national policy and economic factors drastically affected the evolution of coastal wetlands. Human activities, including farmland reclamation, urban construction, and tidal flats exploitation were the main driving forces for the evolution of the Bohai Rim coastal wetlands.

Key words: soil microbial biomass, rhizosphere effect., alpine scrub, warming