Jiahuan Guo

Drought increasingly threatens terrestrial vegetation, whereas current syntheses remain disproportionately focused on seed plants. Ferns and mosses provide a useful contrast because they represent distinct hydration strategies among early-diverging land plants. We compiled 3272 paired observations from 46 drought experiments covering 35 fern species and 41 moss species to compare responses in water status, photosynthesis, chlorophyll fluorescence, oxidative stress, osmotic adjustment, abscisic acid, and growth. Drought reduced physiological performance in both groups, but mosses showed a greater mean decline than ferns. Ferns maintained stable maximum quantum yield and increased nonphotochemical quenching despite reduced pigment content and carbon assimilation, suggesting stronger photoprotective regulation. In contrast, mosses showed coordinated declines in maximum fluorescence, effective PSII yield, and maximum quantum yield, together with elevated minimum fluorescence, indicating direct PSII impairment. Oxidative damage, osmolyte accumulation, and growth suppression were also stronger in mosses. Within ferns, drought sensitivity was concentrated in epiphytic species, especially obligate, canopy, tank-forming, and xerophytic groups. Fern responses were partly explained by provenance climate, drought duration, and specific leaf area. Overall, within the species and experimental conditions represented in the current dataset, ferns largely maintain photochemical stability through photoregulation, whereas mosses shift more rapidly toward PSII impairment, oxidative injury, and growth suppression, highlighting vulnerable components of moisture-dependent ecosystems under intensifying drought.

Mixed‐species plantations are increasingly promoted as a means to enhance soil functioning; yet the global magnitude and consistency of their effects on soil carbon and water dynamics remain insufficiently resolved. We compiled 6550 paired observations from 300 studies to quantify how species mixing influences soil carbon pools and hydrological properties across forest types, soil layers and environmental gradients. We found that species mixing increased soil carbon storage and water holding capacity by an average of 10.5%, with the strongest gains in conifer and broadleaved mixtures. These improvements were underpinned by coordinated shifts in soil physical structure, including lower bulk density, greater aeration, expanded capillary and non‐capillary porosity, and higher infiltration rates. Such structural modification facilitated substantial increases in soil organic carbon and water retention. Responses were most pronounced in topsoil but were also evident in subsoil, revealing depth‐dependent sensitivity and vertical heterogeneity in below‐ground processes. Climate and stand structure exerted strong modulation. Positive effects intensified with mean annual temperature and precipitation, peaked at intermediate elevation, and were greatest in stands with higher species richness and intermediate stand age and stand density. These patterns indicate that species interactions and functional complementarity become more influential in favourable or structurally balanced environments. Synthesis : Our findings show that species mixing enhances soil carbon sequestration and water regulation through integrated physical and biogeochemical pathways. These results highlight species diversity as an effective strategy for strengthening the resilience, productivity and multifunctionality of plantation forests under changing environmental conditions.

Moso bamboo ( Phyllostachys edulis ) expansion threatens subtropical forest biodiversity, yet how intraspecific root trait variation shapes rhizosphere microbial functional potential remains unclear. We aimed to elucidate how bamboo root trait variation and rhizosphere soil properties jointly shape microbial functional gene profiles during expansion. We investigated paired pure bamboo forests (PBF) and mixed bamboo forests (MBF) at four elevations in subtropical China, integrating individual‐level root trait measurements, rhizosphere soil analyses and shotgun metagenomic profiling. Bamboo in MBF exhibited acquisitive root strategies with significantly higher specific root length (615.33 vs. 446.03 cm/g) and specific root area (156.06 vs. 122.86 cm ² /g), but lower root tissue density (0.32 vs. 0.39 g/cm ³ ) compared to PBF. PBF rhizospheres harboured significantly enriched nitrogen and phosphorus cycling genes, with co‐occurrence networks showing substantially higher connectivity in phosphorus metabolism (1520 vs. 788 edges). Structural equation modelling demonstrated that forest type shaped functional gene assembly primarily through soil property modification, with root traits exerting limited direct effects. These findings reveal that established bamboo stands develop self‐reinforcing microbial feedbacks through soil modification, creating functionally integrated rhizosphere communities with enhanced nutrient cycling potential. Expansion fronts, where these feedbacks are not yet established, offer a critical window for management intervention before positive feedbacks strengthen. Read the free Plain Language Summary for this article on the Journal blog.

Mixed-species plantations have been increasingly promoted as a strategy to enhance ecosystem functioning and related ecosystem processes; however, their global impacts on biomass production and nutrient cycling remain uncertain. Here we present a comprehensive meta-analysis based on a random-effects model of 8,450 paired observations from 328 studies spanning diverse climatic zones, stand structures, and silvicultural systems. We demonstrate that species mixing significantly enhances plant biomass and nutrient content compared to monocultures, with positive responses observed across trees, shrubs, litterfall, and both above- and belowground compartments. Mixed-species plantations also increase soil organic carbon, total nitrogen, phosphorus availability, microbial biomass, and leaf nutrient content while maintaining stable soil stoichiometric ratios, collectively reflecting more efficient stand-level nutrient cycling. Importantly, the magnitude of these effects was shaped by climatic and structural contexts, with stronger positive outcomes under warmer and wetter climates, increasing with species richness, and showing unimodal responses to elevation, stand age, and stand density. By synthesizing multi-scale evidence from diverse ecosystems, we reveal that species mixing promotes biomass accumulation, improves nutrient retention, and strengthens biodiversity-nutrient cycling linkages. This study highlights the potential of mixed-species plantations to enhance ecological function, advance forest restoration, and guide plantation management across diverse environmental conditions.

Mixed-species plantations are increasingly recognized for their potential to maintain forest biodiversity and soil health; however, a comprehensive assessment of their global effectiveness is lacking. To fill this knowledge gap, we conducted a meta-analysis of 7,045 paired observations between mixed-species and monoculture plantations, derived from 311 studies across diverse forest ecosystems worldwide. Our results show that mixed-species plantations significantly increased understory plant biomass, cover, and species richness by 32.6%, 55.4%, and 32.2%, respectively, compared to monocultures. Furthermore, the Shannon and Pielou diversity indices increased by 28.2% and 8.6%, respectively, and the Simpson index increased by 9.6%. When understory shrub and herbaceous species were considered separately, species mixing had significantly positive effects on shrub diversity but had no effect on herbaceous diversity. Moreover, mixed-species plantations markedly improved soil physical and chemical properties compared to monocultures. These improvements include increases in soil nutrient content (9.6 to 17.8%) and nutrient availability (14.7 to 33.5%), soil microbial biomass (17.2 to 28.8%), and soil carbon sequestration (7.2 to 19.9%). These enhancements were particularly pronounced in plantations that included legumes. Our findings reveal that the benefits of species mixing are influenced by climatic conditions, geographic location, and stand age, with the most substantial effects observed in temperate regions and mature stands. This study underscores the critical role of mixed-species plantations in promoting sustainable forest management and mitigating the ecological limitations of monocultures.

The soil food web is essential for the functioning of terrestrial ecosystems. The application of naphthalene is a commonly employed experimental treatment for expelling soil fauna to examine faunal effects on litter decomposition processes, for which is it assumed that naphthalene has negligible effects on soil microbial communities. An experiment was conducted to examine the potential soil-fauna-repellent effect of naphthalene application (100 g/m²/month, TR) on a soil fungal community during litter decomposition. The results showed that TR greatly suppressed the abundance and taxonomic richness of soil fauna by 83.7 ± 14.2% and 48.1 ± 17.2%, respectively, and reduced the rates of poplar leaf litter decomposition compared to the control (CK, without naphthalene treatment). Among the fungal communities, the abundance of Thelephorales in the TR soil was suppressed, while the abundance of Capnodiales was stimulated, although TR did not significantly alter the carbon and nitrogen content in the soil microbial biomass nor the diversity of soil fungal communities and the most abundant fungal phylum. Thus, both the suppressed soil arthropod abundance and altered soil fungal community might contribute to the observed slowdown in litter decomposition. These results suggest that naphthalene, as a soil fauna repellent, can alter the abundance of specific taxa in a soil fungal community, thereby impeding the effort to elucidate the contribution of soil fauna to ecosystem functioning (e.g., with respect to litter decomposition).