Background and aims Vascular plants and moss biocrusts are known to coexist in drylands, wherein vascular plant cover is known to be a major influencing factor for biocrusts development. Vascular plants produce litter which may affect moss biocrusts when covering them. However, to which extent the cover of litter may affect the physiology, e.g., photosynthetic activity, of moss biocrusts remains poorly understood.MethodsWe studied the effect of the litter covering on biocrust-forming mosses on the northern Chinese Loess Plateau over four-month period. We used litter from shrubs of Artemisia ordosica and Caragana korshinskii with two levels of litter thickness, and monitored moss greenness, and several indicators of moss physiological activity.ResultsLitter covering reduced moss greenness, content of chlorophyll a and b, soluble sugar, and soluble protein, suggesting a reduced photosynthetic and metabolic activity of mosses under litter cover. On the other hand, mosses covered by litter showed higher contents of malondialdehyde, proline, and catalase activity compared to those mosses without any litter cover, suggesting that litter covering increased oxidative stress in mosses and triggered a protective response against oxidative damage. Moreover, we found litter thickness exerted a more significant impact on the physiological indices of mosses than litter type.ConclusionsOur results demonstrate the detrimental effects of litter covering on the physiological activity of biocrust-forming mosses. The findings provide a mechanistic understanding of the reductions in mosses in ecosystems with high shrub cover, highlighting the importance of litter in mediating the relationships between moss biocrusts and shrub patches.

The state of Pinus cultivation in southern Brazil, from the perspective of potential environmental damage, is controversial. Little is known about naturally regenerated forests after clear-cutting Pinus, particularly regarding ferns, forest structure, and soil composition. This study evaluated differences in fern community structure, forest attributes, and soil properties in a regeneration area 15 years after P. elliottii removal, compared to an Araucaria Forest in the Canela National Forest, Brazil. A 1-hectare plot was divided into 100 m2 subplots, with 12 units randomly selected at each site. In each subplot, all fern species were recorded, and their coverage was measured. Forest and soil parameters were also collected. In the Pinus removal area, forest regeneration shows a fern community with lower species richness, greater floristic homogeneity, and a simplified structure compared to the reference area. Tree species structure differs between sites, with a high density of Pinus and absence of Araucaria angustifolia in the regeneration area. These trees are taller, form a more closed canopy, and create thicker leaf litter. The soil at the regeneration site has lower nutritional quality, greater acidity, and higher aluminum concentration compared to the natural forest. Assisted regeneration is recommended to accelerate and improvide forest recovery.