Effects of sand burial caused by ant nests on soil microbial biomass, basal respiration, and enzyme activity in/under biocrusts in vegetated areas of the Tennger Desert

Abstract

AbstractSand burial of crusts, caused by ant burrowing, is a common phenomenon in desert landscapes, yet the potential impacts on soil processes are unknown. Three sand burial depths, 3.0–5.0 mm (deep burial), 1.0–1.5 mm (shallow burial), and 0 mm (control) affecting two dominant biocrusts (viz., cyanobacteria‐lichen crusts and moss crusts) sampled in the moist and dry seasons were selected to explore this issue in two vegetation areas of the Tennger Desert. We collected 180 samples from biocrust layers and topsoil to assess soil physicochemical properties, microbial biomass, basal respiration, and enzymes activities. The results showed that sand burial of crusts reduced soil microbial biomass, basal respiration, and enzyme activities, while deep burial caused a substantial decline in these parameters. Sand burial interfered with the biocrusts structure (e.g., rupture and flaking) and properties, subsequently causing soil‐nutrient deprivation and soil microclimate deterioration. These are major mechanisms for decreasing soil microbial biomass, basal respiration, and enzyme activities. Moss crusts had significantly higher levels of the microbial parameters than cyanobacteria‐lichen crusts following sand burial, indicating that biocrusts' tolerance to sand burial was synchronized with their progressive succession. In addition, soil microbial parameters were higher in natural vegetation areas than artificial vegetation areas following sand burial. Such observations suggest that high soil fertility could mitigate the negative effects of sand burial on soil processes. In conclusion, sand burial induces biocrust degradation and further disturbs surface soil processes in arid desert ecosystems.