Responses of biological soil crusts to different types of vegetation restoration on the Chinese Loess Plateau: a case study

Abstract

Biological soil crusts (biocrusts) are important components of dryland ecosystems. Vegetation strongly affects the distribution of biocrusts by influencing the soil stability, moisture and light availability. The Loess Plateau has been subjected to large‐scale restoration efforts; however, the type, coverage, and biomass of biocrusts responses to different types of vegetation restoration remain uncertain. Here, we investigated the biocrust characteristics (type, coverage, thickness, biomass, dominant cryptogam species, and relative abundance of major cyanobacteria and algae) in areas restored with different types of vegetation (Caragana korshinskii, Platycladus orientalis, Armeniaca sibirica, Populus hopeiensis, Pinus tabuliformis, Tamarix chinensis) and in a natural grassland on the Loess Plateau. Our results showed that the coverage, thickness, and biomass of the biocrusts were higher in the natural grassland than in the afforested areas, which suggests that the natural grassland is more suitable than the afforested areas for biocrust distribution. The biocrusts were composed mainly of mosses in the Pi. tabuliformis area and of cyanobacteria and algae in most of the other vegetation restoration areas. However, no biocrusts were observed in the T. chinensis area, probably because the dense canopy prevented light from reaching the soil. In addition, soil properties influenced by vegetation restoration may also affect the characteristics of biocrusts. Overall, our study suggests that natural grassland recovery, rather than afforestation, is likely the most suitable method for the development of biocrusts and provides suggestions for restoration and reconstruction on the Loess Plateau.