Correlation analysis of landscape patterns with surface water quality in yancheng coastal wetland, jiangsu, china

Abstract

Quantitatively exploring a relationship between coastal wetland landscape pattern and water quality (WQ) is conducive to providing scientific guidance for the improvement of regional WQ, the prevention of water pollution, and the formulation of regional landscape protection and planning. With the 2019 landscape data and WQ sampling data from the Yancheng Coastal Wetland, five-level WQ sampling points at different scales were established. By applying ecological and statistical analysis methods, correlations between the landscape patterns and WQ indicators in different buffer zones were analyzed. Analysis results showed that: (1) The area of aquafarm, farmland and dry ponds were widely distributed at different scales, and the landscape level index and type level index in different buffer zones were significantly different. (2) There were significant correlations between coastal wetland landscape types and WQ indicators. Total nitrogen, total phosphorus, ammonia nitrogen (NH4+-N), WQ indicators showed significant positive correlations with farmland landscapes in 0.5 km, 1 km, 2 km, and 2.5 km buffer zones, and significant negative correlations with tidal flats in 0.5 km-2.5 km buffer zones. The Chemical Oxygen Demand index was significantly correlated with various landscapes in the area. (3) At the landscape level, the landscape level index, which represents the fragmentation and complexity of coastal wetland landscapes, had a significant correlation with water pollution indicators, such as mean patch areas, fractal dimension, landscape shape index, plaque cohesion, contagion index and other indexes. At the level of landscape class, farmland, aquafarm, dry ponds, construction land in artificial wetlands, and various types of level indexes of Suaeda salsa, Phragmites communis, and Spartina alterniflora in natural wetlands were highly correlated with WQ indicators.