Study on the Evolution Characteristics of Coastal Wetlands of Bohai Sea in Shandong Province under the Influence of Human Activities

Using the coastal area of Bohai Sea in Shandong Province as the study area, the evolution law of coastal wetlands under the influence of human activities is discussed in this paper. The results are as follows. (1) The wetland area in the study area increased from 1990 to 2019, mainly because of the transformation from forest-grassland to a constructed wetland. The area of constructed wetlands increased significantly, whereas the area of natural wetlands decreased significantly. (2) The overall evolution rate of land use was on the rise, with the average value rising from 21.58 in 1990-2000 to 32.01 in 2010-19. The evolution rate from natural wetland to constructed wetland in the western region was generally faster than the rate in the eastern region. (3) The intensity of human activities in the region was different, and the dominant role of wetlands is inversely proportional to the intensity. The areas with higher intensity of human activities increased, whereas the areas with lower intensity of human activities decreased. (4) During the study period, with the increasing of the area of salt fields and the transformation of natural wetlands to other types of land use, the area of wetlands in higher intensity areas was small and increased, whereas in lower intensity areas it was reduced.