Biological crusts in different regions
Biocrusts are ecological restoration engineers for desert areas, containing complex microorganisms that form a layered structure of organic profiles on top of the topsoil. It is mainly composed of bacteria, fungi, cyanobacteria, green algae, lichens, mosses, and other non-vascular plants. These microorganisms can secrete sticky substances such as exopolysaccharides, which can cement soil particles to form a dense layered structure. Biocrusts are the main cover in arid regions, and they can provide key ecological functions to maintain ecosystem stability. For example, increasing soil nutrients, stabilizing soil structure, reducing wind and water erosion, changing soil texture, fixing atmospheric carbon dioxide and nitrogen, regulating soil hydrology, improving water retention, affecting seed germination and plant growth. In China, biological crusts not only exist in arid desert areas, but also in tailings in humid areas and soils of karst landforms. In addition, studies have shown that biological crusts can increase the nutrients in the tailings matrix and change the community composition of karst soils.