Environmental factors influencing the distribution of Tamarix chinensis Lour in the Laizhou Bay wetland of the Yellow River Delta

Analysis of the spatial distribution and influencing factors of plant populations can elucidate plant ecological adaptability and environmental survival strategies. In this study,we investigated the relationship between the characteristics of environment factors and a Tamarix chinensis population in the Yellow River Delta,to determine the spatial distribution pattern of T. chinensis population and the dominant factor influencing the distribution and also to reveal the mechanisms by which environment factors maintain the distribution of T. chinensis population. As a study population,we selected a T.chinensis population in the Shandong Changyi National Ecological Special Reserve,and conducted correlation and principal component analysis of 13 environmental factor parameters,including distance from the sea,groundwater level,soil salinity,soil bulk density and soil porosity,based on sample area and quadrat surveys. The results revealed that the spatial distribution of T. chinensis population in Laizhou Bay shows an aggregative pattern. There were significant positivecorrelations between stand density and distance from the sea and between stand density and groundwater level,whereas there was a significant negative correlation between stand density and soil moisture content. Furthermore,there was a significant positive correlation between soil salinity and soil water content,and significant negative correlations between soil salinity and groundwater level and between soil salinity and soil pore space. There was a significant negative correlation between soil water content and groundwater level. The coefficient of variation among the 13 environmental factors analyzed in relation to T. chinensis in Laizhou Bay was between 0. 060 and 1. 296. The content of K+,soil salinity,and stand density showed the largest ranges of variation,followed by soil organic matter,available phosphorus,and soil organic carbon. The spatial variability of groundwater level was higher than that of distance from the sea. Some basic physical properties,including soil p H,soil bulk density,and total porosity,varied slightly. The soil salt content was 0. 47%,and p H was 8. 48,indicating that the soil of T. chinensis has characteristics of heavy solonchak and meta-alkalescence. The principal component analysis showed that soil salinity was the main factor influencing the distribution of T. chinensis in Laizhou Bay,followed by distance from the sea,soil available phosphorus,and groundwater level