干旱区生态环境知识资源中心

This investigation involves the comparison of the diversity of understorey vegetation of four desert planted forests with the adjacent desert areas. Spatial and temporal variations in species composition and structure were compared, and alpha and beta diversities were compared for the field data collected from sampled sites. The diversity of native desert species decreased from 66% in desert areas to 44% of the total recorded plants inside the forests. Meanwhile, the percentage of agricultural weed species increased in forests to >twofold more than that recorded in desert areas. Plant communities in forest stands shared <50% of their species with adjacent vegetation in desert stands. The percentage of variation in species composition was >340% in some forests compared with the desert areas. Alpha diversity and beta-diversity were significantly higher in forest stands than in the desert. Spatial and temporal variations in species diversity were correlated with type of tree canopy and irrigation system. Planted forests had significant negative effects on the diversity of native desert shrubs and trees. Using flood irrigation and more spacing between trees might help in conserving the floristic diversity of desert shrubs and trees at the forest floor.