Annual Rates, Patterns, and Driving Forces of Coastal Wetland Change in the Liao River Estuary From 1986 to 2018

Abstract:

Coastal wetlands are an important transition zone connecting the sea and land with high biodiversity. The land use land cover (LULC) change, particularly coastal wetland change, has become a non-negligible issue due to intensive human intervention. Taking Liao River Estuary (LRE) wetland in Liaoning Province of China as a case, we applied the Continuous Change Detection and Classification (CCDC) algorithm and Landsat images to explore the spatial-temporal change of coastal wetlands (e.g., reed, suaeda heteropteran, and intertidal zone) from 1986 to 2018 and analyzed the driving factors of natural wetland changes. The overall classification accuracy of CCDC algorithm in LRE wetland reached 87.3%. The results showed that the area of natural wetland in LRE experienced drastic changes declined 25% during study period. The intertidal zone was the most seriously encroached type and its lost area accounted for 17% of the natural wetland area. The area of suaeda heteropteran declined rapidly from 2010 to 2018 while the area of reed had a small increase. The reduction of natural wetland area was mainly caused by human activities including urbanization, tourism, and expansion of aquaculture ponds. Our effort provides direct, specific, and spatially explicit information on changes and causes of coastal wetlands and thus supports the formation of effective plans and policies for coastal management and preservation of coastal ecosystem services.