Distribution patterns of planted-shrubs of different restoration ages in artificial sand-fixing regions in the southeastern Tengger Desert

Abstract

Plant density and spatial distribution in artificial vegetation is obviously initialized at the planting stage. Plant dynamics and spatial pattern may change over time as the result of interactions between individual plants and habitats, but whether it's applied for desert shrubs in artificial sand-fixing regions remains unknown. Here we examined changes in plant densi‐ ty and distribution patterns of three shrubs (Artemisia ordosica Krasch, Caragana korshinskii Kom, and Hedysarum sco‐ parium Fisch.) in different regions, which have been restored for 27, 32 and 50 years (R27, R32, R50), respectively. The vegetation analysis shows that A. ordosica was the dominated species across the 3 restoration regions. The density of A. or‐ dosica and H. scoparium show a significant increase from R27 to R32, then decreased in R50. The density of C. korshin‐ skii was low in R32 and R50, lower in R27. The variance-to-mean ratio (VMR) was used to characterize spatial distribu‐ tion patterns to fit the observed densities of the three shrubs by frequency. A. ordosica and C. korshinskii both show signifi‐ cantly clumped distributions in three restoration regions. H. scoparium show a uniform distribution in R27 and R50, but a clumped distribution in R32. These results show that A. ordosica seems to be more adaptable in revegetated desert areas compared to C. korshinskii and H. scoparium. Pattern analysis suggests a successive replacement of C. korshinskii, which had low proportions of survived shrubs, by the dominant A. ordosica. This study contributes to the understanding of the distribution patterns of shrubs plants in revegetation projects in arid desert areas.