Relationship between topography and the distribution of understory vegetation in a Pinus massoniana forest in Southern China

The poor growth of understory vegetation and the severe losses of soil and water in Pinus massoniana forests have recently become serious concerns in an area in southern China with eroded red soil. The influence of topography on the spatial distribution of vegetation, however, has received little attention. This study combined several multivariate analyses to discern the complicated relationship between understory vegetation and topography. Thirty-six plots (10 m×10 m) were sampled in a field survey of the vegetation and topography in the central red-soil region. The distributions of the understory vegetation differed significantly amongst the topographies. Most plants grew in gullies, and few grew on ridges. The low coverage (25.2%) and number of species (5 per plot) of the vegetation on ridges was due to serious soil erosion. Surface curvature and slope aspect were the first and second most important topographic factors, respectively, affecting the distribution of the vegetation. The relationship between topography and distribution could be described by a linear model. Surface curvature or slope aspect alone, however, could only explain 22.2–59.2% of the variance in distribution. The adaptation of vegetation to specific topographies should be considered for restorations of P. massoniana forests in the study area. The results of this study will be helpful for selecting potential sites for seeding and vegetation restoration to improve the ecology of the study area. Further studies will be needed to identify the mechanism of the distribution of the understory vegetation in these P. massoniana forests.