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Rare earth elements (REEs) exploitation has caused large‐scale desertification. Biocrusts and their microbial community are crucial for the restoration and revegetation of abandoned mine areas. However, little is known about how microbial communities with biocrusts contribute to the sustainable function of degraded mine lands. Here, we evaluated soil nutrients, microbial community structure, and enzyme activities (involved in C, N, and P cycling) underneath moss biocrusts in REEs mine lands in Jiangxi Province, China. The results showed that the dissimilarities in the diversity, and structure of bacteria/fungi community with and without moss biocrusts were significant. Nevertheless, the effects of moss biocrusts on the abundant fractions of bacterial/fungal communities depend on land use types. Moreover, network hubs affiliated with Gammaproteobacteria (OTU7263) and Geodermatophilus sp. (OTU7087) were identified from moss networks, but no hub was found in bare soil. More importantly, the microbial communities underneath moss biocrusts mainly had direct effects on enzyme activities, while the microbial communities in bare soils had a relatively weak direct influence on enzyme activities, and most effects were indirectly driven via soil abiotic properties. Our results contribute to a better understanding of microbial community and corresponding ecological functions with moss biocrusts in degraded mine lands. [ABSTRACT FROM AUTHOR]

Purpose: Bryophytes play an important role in post-mining vegetation succession in metal-mining areas. As a pioneer group, bryophytes can prevent soil erosion, increase soil nutrition, and affect subsequent vegetation succession. This study investigated the diversity and distribution of bryophytes in the ion-type rare earth mining area of southern Jiangxi Province in southeast China to reveal: 1) the key environmental factors influencing bryophytes recovery, 2) the effect of bryophytes recovery through community structure composition, and 3) the most dominant and therefore suitable groups for early vegetation restoration. Methods: Sampling was carried out in five mining areas. In each area, the diversity and distribution of bryophytes in five typical habitats [virgin field (VF), orchard, ammonium deposition leaching (ADL), ammonium in situ leaching (AISL), and cropland] were analyzed. Results: A total of 118 species of bryophytes belonging to 66 genera and 36 families were collected and identified. Endemic species were found in all habitats in the mining area, and the dominant bryophytes were common species in all habitats. The bryophyte diversity showed habitat-related changes, in the following order: cropland > orchard > VF > AISL > ADL. A structural equation model showed that soil moisture and slope location directly affected bryophyte diversity. Bryophyte communities with upright growth were the dominant groups that adapted to the harsh post-mining environment. Edaphic factors had a greater influence on the bryophyte distribution than topographic and biological factors, at both the overall and habitat scale. Soil moisture was the most important factor affecting the overall distribution of bryophytes in the mining area. There were clear differences in the importance of factors affecting the bryophyte community structure in different habitats. Conclusion: Although mining activities significantly reduce bryophyte diversity, bryophyte communities adapt to the lack of water and moisture by adjusting their life-form structure and species composition. The common species in mining areas might be suitable materials for local vegetation restoration. Deliberate manipulation of the terrain, nutrient supplementation, and reducing the concentrations of harmful substances will help accelerate the early succession of vegetation in leached soil. [ABSTRACT FROM AUTHOR]