Feedback between plant diversity and soil under different vegetation restoration modes in desertification areas of northern Guangdong

To explore the internal mechanism between plant species diversity and soil physical and chemical properties in the rocky desertification environment, this article aimed to provide a theoretical basis for the ecological restoration and comprehensive management in the rocky desertification areas.

The typical artificial broad-leaved pure forest (Mode A), artificial coniferous broad-leaved mixed forest (Mode B), artificial broad-leaved mixed forest (Mode C) and natural broad-leaved mixed forest (Mode D), the plant community and soil in each plot were used as research objects, and the species composition, diversity, soil physical and chemical properties of trees were determined.

1) In the process of different vegetation restoration patterns in rocky desertification areas, the number of families, genera, and species in the arboreal layer tends to gradually increase, while the proportion of each family tends to decrease, indicating that the composition of plant families, genera, and species is becoming more diversified and complex. The dominant tree species composition in the shrub and herbaceous layer is similar, almost all being perennial shade-tolerant herbaceous plants; 2) In the rocky desertification areas of northern Guangdong, the biodiversity index of the natural broad-leaved mixed forest in the arboreal layer is higher than that of the artificial forest; the Simpson index for the shrub and herbaceous layer shows natural broad-leaved mix > artificial broad-leaved mix > artificial coniferous and broad-leaved mix, while the Margalef index shows artificial coniferous and broad-leaved mix > artificial broad-leaved mix > natural broad-leaved mix; 3) The soil nutrients in artificial pure broad-leaved forests are significantly higher than in other restoration patterns; 4) Under the natural broad-leaved mixed forest restoration pattern, there is a positive correlation between soil nutrients and biodiversity, while in other artificial forest patterns, soil nutrients show a negative correlation with diversity indices.

Different vegetation restoration measures can change soil properties, which in turn affect the composition of aboveground vegetation. Among the four vegetation restoration patterns, the natural broad-leaved mixed forest shows the best effect. In future rocky desertification control, artificial promotion of succession to broad-leaved mixed forests can be adopted. After the forest canopy is closed, artificial nurturing can be reduced, allowing natural restoration. This can ensure positive growth of the forest stand while maintaining the species diversity of the forest ecosystem.