Large scale environmental drivers of biocrust distribution and development across a sandy desert in China

• Published in: Catena (Giessen) 2021-05, Vol.200, p.105137, Article 105137
• Main Authors: Ju, Meng-Chen, Zhang, Ting-Long, Li, Xin-Kai, Li, Bing-Yin, Li, Yi-Ping, Liu, Qiu-Yu, Wang, Qing-Xuan, Bu, Chong-Feng
• Format: Article
• Language: English
• Subjects: Biological soil crusts; Cover distribution; Development characteristics; Environmental factors; Regional scale
• ISSN: 0341-8162; 1872-6887
• DOI: 10.1016/j.catena.2020.105137

•Environmental factors drive the development of biocrusts in Mu Us Sandland.•Vegetation, aridity, slope were the top 3 factors affecting biocrust distribution.•Moss crusts distributed under low-elevation stable shrubs are disturbed easily.•Cyanobacterial crusts were high-stress resistance, as pioneers in bare land.•Restricting disturbance will promote biocrust development and its eco-function. Biological soil crusts (biocrusts) are widely distributed in arid and semiarid ecosystems and provide critical ecological functions. Understanding how biocrusts change across broad regional scales allows us to manage them more effectively under changing climates and land-use pressures. Based on field surveys, we used boosted regression trees and correlation analysis to examine the changes in cover, distribution and developmental characteristics of biocrust mosses and cyanobacteria, and environmental factors at 40 sites in the Mu Us Sandland in northwestern China. We found that higher elevation sites (~1342 m) were the most suitable for biocrust distribution, and preferred sites were characterized by greater vegetation cover (>43%), values of the aridity index (>0.34), slope (>6.6°), soil pH (>8.85) and soil organic carbon (>0.50%). Increasing levels of disturbance (>1.15 kg dung ha−1) suppressed biocrusts. Moss crust development (e.g., biomass, thickness, bulk density) was significantly positively related to vegetation cover, aridity index, and soil organic carbon, and moss crusts tended to prefer shady shrub communities at low elevations. Shady and steep (5 – 15°) slopes and higher soil nutrient contents were positively correlated with cyanobacteria development. Reduced rainfall and increasing disturbance intensity would reduce the distribution and development of biocrusts. Our study provides a basis for informed decision making about how to manage moss and cyanobacterial crusts in the Mu Us Sandland as the region becomes hotter and drier.