Effects of human activities on landscape alteration and aquatic environmentof coastal wetland in Dagu River Basin

The information of coastal wetland of Dagu River basin, Qingdao, Shandong, East China, was extracted from long-term series of Landsat 5 TM and Landsat 8 OLI remote sensing data of 2000, 2010, and 2019. The effects of human activities on the alteration of coastal wetland landscape in different periods were analyzed by data training analysis and spatio-temporal differentiation of landscape pattern index. Results show that the total area of wetland and water body changed slightly from 2000 to 2019, and the natural wetland landscape area showed a trend of increasing year by year, while the constructed wetland landscape area showed a trend of decreasing year by year. In recent 20 years, the river area of Dagu River has increased and the river channel has become wider. The total area of coastal wetland in Dagu River basin changed a little as a whole. In the natural wetland landscape, except for the wetland area where tidal flat decreased year by year, the wetland area of lakes, shallow sea waters, seasonal rivers, and permanent rivers all were increasedThe patch density index and patch fragmentation index of the coastal wetland increased first and then decreased in Dagu River basin. Reclamation, population growth, urbanization, pollution, seawater intrusion, and environmental protection measures are the main factors and forces for the alteration of the coastal wetland area and landscape pattern in Dagu River basin.