Analysis of Suaeda heteroptera cover change and its hydrology driving factors in the Liao River Estuary wetlands, China

Suaeda heteroptera (S. heteroptera) is the most common indicator plant of solonchak in coastal wetlands of the Liao River Estuary, the influence of meteorology, hydrology environment on vegetation distribution is of growing interest. With the help of satellite remote sensing (RS) technology and geographic information system (GIS), we investigated the spatial-temporal distribution and area change of S. heteroptera in the wetlands of the Liao River Estuary from 1997 to 2016, and the identification of the main driving mechanisms in the S. heteroptera evolution was analyzed in this coastal wetland. The SPSS Statistics 22 software was used to calculate the correlation coefficients between total area of S. heteroptera and each driving factor based on available long-term (1997-2016) and medium-term (2007-2016) data. Correlation analysis results indicated that the change in S. heteroptera coverage had insignificant correlations (correlation coefficients r=-0.241, r=-0.188 and r=-0.269) with annual mean temperature, precipitation, and sunshine duration, respectively. The results also showed that the growth of S. heteroptera was extremely relevant to runoff from the Liao River from April to June (r=0.889) over the last 10 years. This study revealed that some potential factors, such as river discharge may be related to the large-scale degeneration of S. heteroptera in Liao River Estuary wetlands.