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Soil water is one of the most important environmental factors that influences seed germination, seedling establishment, and plant distribution. There is a close relationship between the distribution of pioneer plants and soil water content in sandy regions. By observing the distribution patterns of pioneer plants and soil water, we determined the relationship between soil water and the distribution patterns of pioneer plants during the process of sand dune invasion in the Horqin Sandy Land, northeast China. The results showed Artemisia wudanica, Agriophyllum squarrosum, Corispermum candelabrum, and Setaria viridis serve as pioneer plants on sand dunes, and the first three of these species accounted for 99.9% of all plant individuals. The majority of these pioneer plants germinated after the first and second effective precipitation events (quantity of rainfall >5 mm) under suitable temperature conditions. Pioneer plants showed non continuous, patchy, and mosaic distribution patterns on sand dunes. Significant relationships were found between the pioneer plant distribution pattern and soil water content. The distribution pattern of C. candelabrum was significantly influenced by soil water content at depths of 0-5 cm, and A. squarrosum was significantly influenced by soil water content at depths of 0-40 cm. This study contributes to understanding of the distribution patterns of pioneer plants and their adaptation to soil moisture in sand dune environments. (C) 2017 Elsevier B.V. All rights reserved.