Identification and Visualization of Complex Spatial Pattern of Coastal Dune Soil Properties Using GIS-Based Terrain Analysis and Geostatistics

Abstract

Coastal dunes display complex relationships among soil properties, vegetation, and geomorphology driven by marine and atmospheric dynamics. Considering topography as a fundamental control of the relations, this study investigated its influence on the spatial pattern of soil attributes in a coastal dune. We systematically collected 193 soil samples at intervals of 20 m from the Sindu coastal dunefield, South Korea, and analyzed 11 soil attributes. Principal component analysis extracted four main factors explaining ca. 75% of total soil variance. Correlation between each soil factor and topographic attributes calculated from raster digital elevation models permitted us to infer relationships between dune configuration and soil spatial variability. Interpretation of the first two factors demonstrated that nutrient input from marine sources by aeolian processes and topographic relief, an indirect measure of depth to the freshwater table, were two major determinants of the spatial distribution of soil properties. For the first factor, distance from the seashore proved to be the most significant indicator of edaphic conditions. Upslope area and wetness index were good proxies for the second factor, dune relief. These two variables significantly explained the distribution of soil moisture. A conceptual model is presented to describe how complex dune soil systems are created from simple topographic effects. The model addresses the importance of integrating foredune, dune slack, and inner dune ridge into one continuous system because topography, geomorphic (aeolian) processes, vegetation, and edaphic conditions are closely connected in a causal chain across the whole dune area.