Landscape pattern changes and its drivers inferred from salt marsh plant variations in the coastal wetlands of the Liao River Estuary, China

Abstract

Coastal wetlands are important ecosystems that connect land to open sea, and their service functions are important in estuaries globally. Using long time series of remotely sensed information, transfer matrix and direction of landscape types from 1986 to 2020 in the coastal wetlands of the Liao River Estuary (LRE) were selected to investigate landscape pattern changes. And the dynamic response of Suaeda salsa (S. salsa) to hydro-climatic factors were explored using partial correlation and nonlinear analysis. The results suggested that landscape fragmentation and abundance have increased with frequent disturbance in the LRE over the last three decades, and more than 60 % of S. salsa, tidal flats, and water transitioned into buildings, farmland, and Phragmites australis (P. australis) in the study area. Further analyses of dynamic response of landscape metrics to influence factors indicated that the main drivers forcing landscape pattern changes in coastal wetlands in the LRE were socio-economic factors, followed by natural factors. The S. salsa spatial variations were positively correlated with river discharge and precipitation but without significant correlation with temperature in the early growing stages of vegetation (P < 0.05) in the coastal wetlands of the LRE, which implied that S. salsa growth mainly relies on river discharge and precipitation by reducing water salinity. Present study may provide new insights into restoration guidance and environmental management for coastal wetland protection.

Keywords

• Liao River Estuary
• Fragmentation
• Suaeda salsa
• Landscape pattern
• Drivers
• Remotely sensed information