Abstract:
To evaluate the restorative potential of moss–algal biological soil crusts (biocrusts) on alpine construction spoil, we conducted a comparative field experiment at a spoil-disposal site. We established contrasting moss–algal assemblages and quantified their effects on soil physicochemical properties, enzyme activities, and microbial communities. Biocrust colonization increased soil ammonium nitrogen up to 2.68-fold, nitrate nitrogen up to 2.85-fold, available phosphorus up to 7.67-fold, and soil organic carbon to 26.11 g/kg. Cellulase, β-glucosidase, and phytase activities reached 2.00, 2.29, and 45.6 times the control levels, respectively. Additionally, biocrusts enhanced microbial α-diversity and evenness, and enabled the detection of rare phyla such as Synergistota and Dadabacteria. Overall, moss–algal biocrusts improved soil nutrient status and optimized the structure of soil microbial communities. These findings provide theoretical and practical guidance for applying biocrust technology to ecological restoration of alpine spoil sites.