Knowledge regarding changes in soil microbial communities with forest succession is vital to understand soil microbial community shifts under global change scenarios. The composition and diversity of soil microbial communities across a subalpine forest successional series were therefore investigated in the Wanglang National Nature Reserve on the eastern Qinghai-Tibet Plateau, China. The calculated diversity indices of soil bacteria (8.598 to 9.791 for Shannon-Wiener, 0.997 to 0.974 for Simpson, 4131 to 4974 for abundance-based coverage estimator (ACE) and 3007 to 3511 for Species richness indices), and ACE (1323 to 921) and Species richness (1251 to 879) indices of soil fungi decreased from initial to terminal succession stages, but Shannon-Wiener and Simpson of soil fungi indices varied slightly with forest succession. Meanwhile, the composition and structure of soil microbial communities varied markedly with forest succession. The relative abundance of the dominant bacterial phyla (Acidobacteria, Firmicutes and Actinobacteria) and fungal taxa (Mortierellomycota, Rozellomycota and unassigned phylum clade GS01) varied considerably with forest succession. However, regardless of successional stage, Proteobacteria and Acidobacteria dominated soil bacterial communities and Ascomycota and Basidiomycota dominated soil fungal communities. Moreover, the changes in soil microbial diversity with forest succession were significantly affected by soil pH, soil organic carbon, soil temperature, altitude, and non-woody debris stock. Importantly, soil pH was the dominant driver of soil microbial community shift with forest succession. In conclusion, the forests at different succession stages not only conserve same microbial populations, but also nurse unique microbial diversity across the forest succession series; and the biodiversity of soil bacterial and fungal communities has differential responses to forest succession.

Daily activity in herbivores reflects a balance between finding food and safety. The safety‐in‐numbers theory predicts that living in higher population densities increases safety, which should affect this balance. High‐density populations are thus expected to show a more even distribution of activity—that is, spread—and higher activity levels across the day. We tested these predictions for three ungulate species; red deer (Cervus elaphus), roe deer (Capreolus capreolus), and wild boar (Sus scrofa). We used camera traps to measure the level and spread of activity across ten forest sites at the Veluwe, the Netherlands, that widely range in ungulate density. Food availability and hunting levels were included as covariates. Daily activity was more evenly distributed when population density was higher for all three species. Both deer species showed relatively more feeding activity in broad daylight and wild boar during dusk. Activity level increased with population density only for wild boar. Food availability and hunting showed no correlation with activity patterns. These findings indicate that ungulate activity is to some degree density dependent. However, while these patterns might result from larger populations feeling safer as the safety‐in‐numbers theory states, we cannot rule out that they are the outcome of greater intraspecific competition for food, forcing animals to forage during suboptimal times of the day. Overall, this study demonstrates that wild ungulates adjust their activity spread and level based on their population size.

Investigations on the budget of plant litter and litter carbon in forest streams can provide a key scientific basis for understanding the biogeochemical linkages of terrestrial–aquatic ecosystems and managing forest catchments. To understand the biogeochemical linkages among mountain forests, riparian vegetation, and aquatic ecosystems, the changes in litter input and output from the subalpine streams with stream characteristics and critical periods were investigated in an ecologically important subalpine coniferous forest catchment in the upper reaches of the Yangtze River. The annual litter input to the stream was 20.14 g m⁻² and ranged from 2.47 to 103.13 g m⁻² for 15 streams during the one-year investigation. Simultaneously, the litter carbon input to the stream was 8.61 mg m⁻² and ranged from 0.11 to 40.57 mg m⁻². Meanwhile, the annual litter output varied from 0.02 to 22.30 g m⁻², and the average value was 0.56 g m⁻². Correspondingly, the litter carbon output varied from 0.01 to 1.51 mg m⁻², and the average value was 0.16 mg m⁻². Furthermore, the average ratio of litter carbon input to output was 270.01. The maximum and minimum values were observed in the late growing season and the snowmelt season, respectively. Additionally, seasonal variations in temperature, together with the stream length, dominated the input of litter and litter carbon to the stream, while the precipitation, temperature, water level, and sediment depth largely determined their output. Briefly, the seasonal dynamics of litter and litter carbon were dominated by stream characteristics and precipitation as well as temperature patterns.

Dissolved carbon (DC) in forest streams plays a crucial role in maintaining the structure and productivity of adjoining aquatic ecosystems as well as informing biogeochemical links between mountain forests and adjoining rivers. Nevertheless, the functions of forest stream DC dynamics are rarely incorporated into river management. To better understand the biogeochemical links between subalpine forests and adjoining streams, the seasonal dynamics of DC in 15 representative forest streams were investigated in a geographically fragile subalpine-gorge catchment in the upper reaches of the Yangtze River. Depending on stream characteristics and critical periods, the DC stocks in the streams ranged from 0.22 to 2.35 mg m⁻² for total DC, from 0.10 to 1.66 mg m⁻² for dissolved inorganic carbon (DIC), and from 0.12 to 1.27 mg m⁻² for dissolved organic carbon (DOC). Moreover, the annual stocks of DC, DIC, and DOC were 1.01, 0.56, and 0.45 mg m⁻², respectively. Correspondingly, the averaged export rates for DC, DIC, and DOC from the forest streams ranged from 0.27 to 1.98 mg s⁻¹, from 0.24 to 1.48 mg s⁻¹, and from 0.18 to 0.90 mg s⁻¹, respectively, in the subalpine forest catchment. The annual export rates of total DC, DIC, and DOC were 1.06, 0.75, and 0.31 mg C s⁻¹, respectively. In particular, the highest rates of export were 4.67, 3.53, and 1.34 mg s⁻¹ for DC, DIC, and DOC, respectively, in the snowmelt period. The average ratios of DOC to DIC stock in the export water ranged from 0.23–2.41 for the 15 streams, and the average value was 0.85 during this one-year investigation. In addition, the maximum and minimum values of the DC stocks, their exports, and the DIC:DOC ratio were consistently observed during the snowmelt season and the late growing period. In summary, precipitation, temperature, water discharge rate, and sediment depth regulated the stocks and export rates of DC and its components. In general, forest streams are important links between the carbon biogeochemical cycle of subalpine forests and adjoining streams.

Societal Impact Statement: Soil organic carbon (SOC) is vital for soil health, food security and climate change mitigation. We reviewed how silicon (Si) fertilisers, commonly used to improve plant health, may also influence SOC dynamics. We developed a framework linking Si and SOC and discussed the possibility of Si‐mediated plant changes contributing to SOC sequestration. We highlight that Si fertilisation is a potential strategy to reconcile the contradiction between intensive agriculture and the need to sequester carbon, supporting both productivity and decarbonisation goals. Summary: The quantity and quality of plant C inputs to soil significantly influence decomposition and stabilisation processes which primarily affect the dynamics of soil organic carbon (SOC). Si has emerged as an important element for improving plant performance, which in turn affects the quantity and quality of such plant C inputs. Research on the interaction between Si and plant biochemical processes highlights a trade‐off between Si and C. Additionally, Si alters plant stoichiometry and belowground C allocation by promoting nitrogen (N) and phosphorus (P) use efficiency, potentially impacting C cycling in rhizosphere processes. However, these processes have not been thoroughly understood to date, limiting our understanding of the role of Si in soil C cycling. This review synthesises existing literature to advance the understanding of plant silicification in soil C cycling. For the first time, we propose a framework linking plant silicification and soil C cycling, via two pathways. First, Si affects C cycling during plant litter decomposition by altering plant chemical composition. We hypothesise that Si‐mediated changes in stoichiometry and C quality reduce litter stability and accelerate processing by the soil community, ultimately promoting SOC stabilisation. Second, Si‐enhanced plant nutritional status may alter belowground C allocation, impacting rhizosphere C cycling. We expect that plant silicification would reduce native rhizosphere SOC loss by the rhizosphere priming effect, as improved plant nutritional status results in less belowground C allocation for resource acquisition. We consider that Si fertilisation could contribute to maintaining soil health, particularly in agricultural systems.