Effective erosion mitigation in the Pisha sandstone region is crucial for soil and water conservation in the Yellow River Basin, yet existing vegetation measures are inadequate in water-limited environments. This study examines the application of drought-tolerant biological soil crusts (biocrusts) for erosion control on sandstone slopes and evaluates their erosion-reducing effects under varying coverage and slope conditions through controlled artificial rainfall experiments. Key findings include: (1) biocrusts coverage demonstrated a linear relationship with initial runoff generation time and an exponential relationship with stable runoff generation time. On average, biocrusts delayed initial runoff generation by 396.32 % and extended stable runoff generation time by 153.93 %, thereby increasing the threshold for both initial and stable runoff generation on Pisha-sandstone surfaces. (2) biocrusts reduced runoff volume by an average of 23.89 %, enhanced infiltration volume by 69.19 %, decreased sediment yield by 64.24 %, and lowered the soil erosion modulus by 68.98 %. These results indicated significant promotion of water infiltration and reduction of water erosion. Both effects were positively influenced by coverage and negatively impacted by slope gradient. A critical slope angle of 15 degrees and a critical coverage of 60 % were identified. When the slope was gentle (S 15 degrees), the negative impact of slope predominated, diminishing the positive effect of biocrusts. Additionally, when coverage reached or exceeded 60 %, further increaseing in coverage accelerated the enhancement of infiltration and erosion reduction. Below this threshold, the rate of improvement gradually diminished with increasing coverage. (3) The structural equation model further elucidated that biocrusts mitigate erosion by enhancing the coverage, thereby reducing runoff velocity and modifying the runoff regime. This mechanism effectively dissipates runoff energy, leading to a decreased soil detachment rate and alleviation of soil erosion. Additionally, the relationship between runoff energy and soil detachment rate follows a power function curve, providing an effective method for predicting erosion in Pisha sandstone area. Consequently, biological soil crust technology shows considerable potential for preventing water erosion damage on Pisha sandstone slopes across various gradients.

Biological soil crusts (BSCs) play a fundamental role in desert ecosystems by stabilizing soil, cycling nutrients, and retaining moisture. However, the assembly processes governing bacterial communities within BSCs remain largely unknown. This study aimed to reveal the spatiotemporal variations in the bacterial community diversity, co-occurrence patterns, and ecological assembly processes of BSCs and their underlying soils across different desert and seasonal conditions. We systematically analyzed the spatial differences in the bacterial diversity, co-occurrence networks, and community assembly processes of BSCs and their underlying soils using samples collected at various soil depths from different BSC types in different deserts. We discovered that BSC type and soil depth were the primary factors driving bacterial community assembly, while seasonal effects were weaker and more indirect, and mainly regulated community dynamics through changes in resource availability and environmental conditions. The underlying soils of moss- and lichen-BSCs exhibited higher bacterial diversity and richness than those of algae BSCs. In contrast, cyano-BSCs exhibited a lower diversity, but Cyanobacteria demonstrated the highest photosynthetic function. Among the different deserts, the community assembly of samples from the eastern Inner Mongolia deserts was largely influenced by environmental selection, whereas stochastic processes were more prominent in the central and western desert regions. A beta-nearest taxon index (beta NTI) analysis indicated that stochastic processes were dominant in surface BSC samples, while environmental selection played a stronger role in deeper layers. A co-occurrence network analysis revealed that surface BSC samples had a high degree of network connectivity, with those from moss- and lichen-BSCs being particularly high, and they also exhibited high modularity and local clustering that promoted the functional stability of the microbial communities. This study revealed the integrated effects of soil depth, BSC type, desert type, and resource availability on microbial community assembly in desert ecosystems. These findings provide a theoretical basis for the microbial management of BSCs and scientific insights to support restoration strategies in desert ecosystems.

Drylands are limited by water and nutrients and exposed to high solar radiation, which result in sparse vegetation cover, soil erosion, and subsequent land degradation. Land degradation affects human wellbeing, causing health and environmental problems, migrations and increasing socio-economic instability worldwide. The restoration of degraded drylands by induced biocrusts has recently gained increased scientific interest. However, harsh environmental conditions can slow down biocrust development. Thus, it is necessary to investigate and develop methods for the mitigation of harsh environmental factors. This survey and assessment reviews studies on environmental barriers to biocrust development and technological achievements in the acceleration of artificially induced biocrust development through the mitigation of harsh environmental conditions. Climatic conditions, and soil and inoculum properties have been identified as major factors that influence the acceleration of biocrust development and which should be considered when dryland restoration is planned. Activities such as watering, shading, soil stabilization and fertilization, as well as further measures for the survival of the cyanobacterial inoculum have promoted biocrust establishment. The restoration of degraded substrates requires the alignment of amelioration techniques with environmental conditions and inoculum requirements. This study has also identified the need for further optimization of watering and shading technologies, better understanding of the importance of soil properties in biocrust growth, as well as further studies on the most appropriate inoculum type and techniques for mass cultivation and application at field scale. The proposal of a multifunctional solution is proposed that could contribute to the restoration of land and cleaner air and water, by providing an inoculum and suitable microsite environmental conditions for the accelerated establishment of viable biocrusts leading to further development, survival, and to the succession to higher organisms under a wide range of environmental conditions.

The Qinghai-Tibet Plateau is now experiencing ecological degradation risks as a result of climate change and human activities. The alpine grassland ecology in permafrost zones is fragile and susceptible to deterioration due to its high altitude, low temperature, and limited oxygen, which complicates the repair of damaged land. Biological soil crusts (BSCs) are crucial for land restoration in plateau regions because they can thrive in harsh conditions and have environmentally beneficial traits. Inoculated biological soil crust (IBSC) has shown success in low-altitude desert regions, but may not be easily duplicated to the plateau environment. Therefore, it is essential to do a comprehensive and multifaceted analysis of the basic theoretical comprehension and practical application of BSCs on the Tibetan Plateau. This review article aims to provide a brief summary of the ecological significance and the mechanisms related to the creation, growth, and progression of BSCs. It discusses the techniques used for cultivating BSCs in laboratories and using them in the field, focusing on the Qinghai-Tibet Plateau circumstance. We thoroughly discussed the potential and the required paths for further studies. This study may be used as a basis for selecting suitable microbial strains and accompanying supplemental actions for implementing IBSCs in the Qinghai-Tibet Plateau.

Spring, especially the freeze-thaw season, is considered the key period for the growth and carbon sequestration of desert mosses. It is not clear how the change in environment water and temperature affects the physiological characteristics of desert mosses in freeze-thaw season. In this study, the effects of water and freeze-thaw cycles on the physiological characteristics of Syntrichia caninervis were assessed by manipulating the increase or removal of 65% snow and changes in the freeze-thaw cycles. The results showed that the changes in snow depth, freeze-thaw cycles, and their interaction significantly affected the plant water content, osmoregulatory substances content, antioxidant substance, and antioxidant enzyme activities. The contents of free proline, soluble sugar, ascorbic acid (AsA), reduced glutathione (GSH), and malondialdehyde (MDA), and superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities increased significantly with the decrease in snow depth and freeze-thaw cycles. POD and free proline were the most sensitive to the snow depth and freeze-thaw cycles, while SOD and CAT were the least sensitive. Therefore, compared with the increase in freeze-thaw cycles, the reduction in freeze-thaw cycles weakened the physiological sensitivity of S. caninervis to snow depth changes.