Drought represents a paramount abiotic stressor constraining global agroforestry productivity. Plants have evolved multifaceted adaptive strategies involving active modulation of symbiotic microbial communities to mitigate drought stress. These plant-associated microbes enhance plant drought adaptation via five principal mechanisms: (i) extracellular polymeric substance-mediated biofilm formation on plant surface enhances hydroregulation and edaphic structural stability; (ii) osmoprotectant biosynthesis (e.g., proline) maintains cellular osmotic equilibrium; (iii) synthesizing antioxidants to reduce damage from reactive oxygen species and oxidative stress; (iv) regulating plant phytohormone metabolism by secreting hormones (e.g. indole-3-acetic acid) and 1-aminocyclopropane-1-carboxylic deaminase; (v) emitting signaling molecules (e.g. volatile organic compounds, hormones and enzymes) to activate plant drought adaptation. Future researches should focus on the development of host-specific drought-adaptive microbial consortia while elucidating phyllosphere–rhizosphere microbiome crosstalk, ultimately harnessing translational microbiome engineering to evaluate their efficacy in multi-environment agricultural systems.

We screened 161 eligible papers of experimental data across the Tibetan plateau for Meta-analysis, in order to systematically assess and validate potential application of plant resource allocation strategies, such as the optimal allocation hypothesis, the isometric allocation hypothesis, and the allometric allocation hypothesis under environmental changes, and to explore the effects of environmental factors (temperature change, grazing intensity) on plant resource allocation strategies in alpine grassland ecosystems on the Tibetan Plateau. Overall, we found that the aboveground and belowground growth relationship in alpine grasslands follows the allometric growth hypothesis, which was unaffected by warming, grazing and their interactions. In addition, the biomass transferred between aboveground and belowground, the former was decreased, while the later was increased under warming condition in alpine steppe implies that the resource allocation strategy in alpine steppe grassland may potentially follow the optimal allocation hypothesis. We further found that the effect of soil properties on biomass, not the biomass allocation, was different under warming and grazing condition in alpine grasslands, which further conforms the above conclusion. In addition, warming helped to mitigate the negative effects of grazing, which indicated that the interaction between warming and grazing is important in alpine grassland ecosystems. Overall, results of this study are of theoretical significance for understanding how moderate grazing affects the growth of plants in alpine grasslands under changing climate.

Terrestrial plants are colonized by various microorganisms in the rhizosphere, phyllosphere and endosphere. Variations of microorganisms between these niches could affect plant performance. While studies have indicated that microorganisms associated with invasive plants may facilitate their invasion success, niche effects on the composition, function and co-occurrence network of invasive plant microbiomes remain poorly understood. In this study, we investigated the bacterial and fungal communities in the rhizosphere soil, root and leaf endospheres of two invasive plants, Flaveria bidentis and Eclipta prostrata. Flaveria bidentis is a recently introduced species (introduced in 2001), whereas E. prostrata has been invaded in China for over 1000 years. We found that microbial community of F. bidentis and E. prostrata harbored more specialists, fewer unique amplicon sequence variants (ASVs), and lower diversity and network complexity in the leaf endosphere than that in the rhizosphere soil. Moreover, the bacterial and fungal communities in the rhizosphere soil, root and leaf endospheres of F. bidentis were more diverse, included more unique ASVs, and had a higher network complexity than those of E. prostrata. Predicted functional profiles revealed that there were more beneficial bacteria and fewer pathogenic fungi associated with F. bidentis than those with E. prostrata. These results demonstrate that there is a significant niche differentiation in the two invasive plant microbiotas, and this work may also indicate potential impact of residence time of invasive plants on plant-microbe interactions.

Microbial necromass carbon (MNC) contributes largely to soil organic C (SOC) pool in terrestrial ecosystems. However, the pattern and underlying mechanisms of MNC and their contribution to SOC along elevational gradients are controversial due to montane ecosystems subject to environmental change. Here, in this study, we investigated the seasonal variation of MNC, its contribution to SOC, the necromass accumulation coefficient and the influencing factors across different elevations in the mountain forests ecosystem of Southwest China. Soil microbial biomass rather than MNC showed seasonal variations, this decoupling pattern was mainly attributed to higher soil extracellular enzymes (i.e. N-hydrolyzing enzyme) and C:N ratio, which accelerated the decomposition of MNC especially bacteria necromass C (BNC) during the humid and warm wet season. In contrast, the drought and cold conditions in dry season inhibited microbial activities and conversion to MNC. During the dry season, the MNC and MNC/SOC exhibited hump-shaped pattern along elevational gradients. The fungal necromass C (FNC) was positive with fungal biomass, indicating that living biomass may have a greater influence on the accumulation of FNC than BNC. On average, MNC constituted about 15% of SOC, with the contribution from FNC (11.9%) surpassing that from BNC (3.1%). The joint effects of soil pH and clay composition significantly influenced MNC dynamics along elevational gradients. These findings demonstrate that the rapid decomposition of BNC is the main way of MNC loss in wet season in the mountain forests ecosystem and further highlight the importance of microbial traits in MNC accumulation.

The distribution and assembly of plant species is a fundamental ecological question. Understanding how various drivers of community assembly vary along elevational gradients and differentially affect species occurrence versus abundance is critically important. Using an advanced tool, the joint species distribution model (JSDM), we aim to investigate shifts in the relative importance of climatic and non-climatic effects on forest community assembly along large elevational gradients, and to compare the elevational trends of these effects on species occurrence and abundance. We documented 243 forest plots, each with a size of 20 × 30 m, along elevational gradients (700–3650 m) of Qinling Mountains, the highest mountain in Central China. We performed JSDMs to quantify the relative importance of climatic and non-climatic effects on species occurrence and abundance along elevational gradients. Climatic and non-climatic effects exhibited distinct elevational trends and differed in their respective influences on species occurrence and abundance. The influence of climate on species abundance increased with elevation, whereas its effect on species occurrence showed a weak decline. At lower elevations, species occurrence was mainly determined by climate, while abundance was affected by both climatic and non-climatic drivers. At higher elevations, climate emerged as the dominant factor affecting both occurrence and abundance. Our study reveals different trends of climate and non-climate effects on species occurrence versus abundance. These findings underscore the importance of jointly considering both types of environmental drivers and both occurrence and abundance, which is critical for predicting community dynamics under climate change and guiding conservation strategies.

Plant and soil microbial communities jointly sustain ecosystem multifunctionality (EMF) in temperate grasslands, yet their relative contributions to EMF under grazing management remain poorly understood. We simultaneously investigated three temperate grasslands to assess the effects of grazing management, climate, edaphic properties, and plant and microbial communities (diversity and community composition) on EMF (quantified by potential soil nitrogen (N) mineralization, arbuscular mycorrhizal fungal infection rate, phospholipid fatty acid, soil total carbon (C) and N, inorganic N, and plant biomass). Using random forest modeling, we identified important predictors, followed by structural equation modeling (SEM) to disentangle their relative roles. The results showed consistent declines in plant diversity and EMF with increasing grazing intensity, while soil bacterial and fungal diversity exhibited minimal responses. Heavy grazing management significantly reduced the abundance of perennial forbs and rhizome grasses, but increased that of annuals and legumes. Concurrently, we observed a significant decrease in copiotrophic Proteobacteria abundance accompanied by an increase in oligotrophic Gemmatimonadetes abundance. Random forest modeling identified grazing intensity, climate, soil properties, plant diversity and community composition, and bacterial community composition as important predictors of EMF. SEM revealed that plant diversity was the dominant biotic predictor of EMF, exceeding the influence of microbial communities across all grasslands. Notably, aridity indirectly influenced EMF through plant diversity rather than direct regulation. These findings demonstrate that plant diversity primarily maintains EMF under grazing pressure, highlighting the importance of biodiversity-focused management strategies in temperate grassland conservation.

Grasslands are highly diverse ecosystems providing important ecosystem services, but they currently face a variety of anthropogenic stressors simultaneously. Quantifying grassland responses to global change factors (GCFs) is crucial for developing effective strategies to mitigate the negative impacts of global change on grassland communities and to promote their resilience in the face of future environmental challenges. We conducted a field experiment in the Songnen grassland, northeastern China, to test the combined effects of 0, 1, 2, 4, 6, and 8 GCFs, including fungicide, herbicide, insecticide, antibiotic stress, heavy metal pollution, light pollution, microplastic pollution, nitrogen deposition, tillage disturbance, and increased precipitation. We found that within one year, the increasing number of GCFs negatively impacts both the productivity and diversity of grassland communities. In comparison to exposure to a single GCF, exposure to 8 GCFs led to a reduction in productivity and species richness by 42.8% and 42.9%, respectively. Furthermore, these negative effects seem to be linked to the reduction of dominant species and the concurrent increase in neonative species (i.e., species that have expanded their geographic range into a new area without direct human assistance, but as an indirect consequence of human-induced environmental changes). The results of hierarchical diversity-interaction modeling suggested that the adverse impacts of an increasing number of GCFs on community productivity and diversity are attributable to both the specific identities of GCFs involved and their unique pairwise interactions. The results suggest that grasslands may quickly lose stability and degrade more rapidly in response to multiple co-occurring GCFs. Greater efforts should be made to conserve the functions and services of grassland ecosystems by reducing the impacts of human activities.

Understanding leaf phenology is essential for capturing forest dynamics, yet traditional monitoring methods fail to resolve vertically stratified phenology due to canopy occlusion and limited spatial coverage. To address this gap, we developed an integrated unmanned aerial vehicle and ground-fixed camera system enabling simultaneous monitoring of forest overstory and understory phenology. Deployed in a subtropical forest during 2017–2023, this system archived 0.075 m × 0.075 m resolution aerial imagery and hourly ground photography, tracking vegetation dynamics across community and species scales. Our system-derived Green Chromatic Coordinate was strongly correlated with Normalized Difference Vegetation Index (r = 0.82), Enhanced Vegetation Index (r = 0.91), Gross Primary Productivity (r = 0.95) and Leaf Area Index (r = 0.79 for overstory; r = 0.92 for understory) validating its effectiveness as a phenological proxy in subtropical forests. Critically, the understory exhibited delayed leaf maturation (16.2 days) and senescence (61.2 and 11.6 days for start and end of leaf falling, respectively) compared with the overstory, revealing a vertical ‘phenological escape’ phenomenon. These phenological mismatches buffered seasonal productivity fluctuates, by sustaining carbon uptake during overstory senescence. Our approach overcomes the limitations of fixed observation towers and satellite imagery by offering flexible, scalable and cost-effective monitoring of vertical stratification in forests. By quantifying vertical layer interactions, our approach advances predictive modeling of ecosystem–climate feedback and guides forest management under climate change.

Peatlands store approximately one-third of global soil organic carbon (SOC) and clarifying SOC sources is essential to assess soil carbon (C) formation and stability in these C-rich ecosystems. However, large-scale patterns and drivers of plant- and microbial-derived C in peatlands remain poorly understood. This study applied lignin phenols and amino sugars as biomarkers for plant and microbial residues to investigate the regional distributions and controlling factors of plant- and microbial-derived C in surface peat (0–20 cm) across Zoige alpine peatlands. Our results showed that amino sugars contributed less while lignin phenols remained stable with SOC accrual, indicating the key role of plant-derived C in SOC accumulation. Soil nutrients and microbial properties explained the majority of the variation in lignin phenols, while soil nutrients and mineral protection played a more important role in amino sugars than microbial variables and climatic factors. Specifically, lignin phenols were negatively correlated with soil nutrients, fungal richness, and acid phosphatase activity, while showing a positive association with leucine aminopeptidase activity. In contrast, amino sugars were positively related to soil total phosphorus but negatively linked with Fe-associated C and Fe/Al-oxide. These findings provide the first empirical evidence of plant- and microbial-derived C and their divergent drivers in alpine peatlands over broad geographic scale, which advances our understanding of soil C formation and stability in these C-rich, climate-sensitive ecosystems.

The home-field advantage (HFA) hypothesis posits that leaf litter decomposes faster at its native sites (‘home’) than in foreign sites (‘away’). While litter quality critically regulates decomposition and HFA, the interplay among litter quality, soil nutrients, and microbial activity in driving HFA remains poorly understood. We examined these dynamics in subtropical forests using Pinus massoniana (low-quality litter) and Schima superba (high-quality litter) in a reciprocal transplant decomposition experiment, including a 1:1 mixed-litter treatment. Our results revealed pronounced HFA effects in both forest stands, but litter quality was negatively correlated with both the decomposition rate and HFA magnitude. Soil nutrients regulated HFA effects, accounting for 56% of the variation in low-quality litter (vs. 25% for high-quality litter). Low-quality litter exhibited greater sensitivity to soil microbial metabolic activity. Soil microbial biomass enhanced HFA in the low-quality litter forest stand but suppressed it in the high-quality forest stand. Enzymatic activity (e.g. β-1,4-glucosidase) directly mediates HFA, particularly in the high-quality litter. These findings underscore litter quality as a pivotal factor governing HFA through its interactions with soil nutrients and microbial metabolism, with implications for predicting biogeochemical cycles in forest ecosystems.

Environmental changes, especially climate variability, can substantially influence phenological patterns of plants and their associated insect communities, potentially reshaping the spatial distribution of their interactions. Despite considerable attention on species range shifts under climate change, empirical studies explicitly addressing how these shifts affect spatial matching between plants and their associated insect communities remain scarce. Here, we investigated inter-annual changes in the spatial matching between the poisonous weed Stellera chamaejasme L. and its associated floral visitor community along an altitudinal gradient over two climatically distinct growing seasons in the Qilian Mountains, China. We monitored the flowering phenology of S. chamaejasme and the abundance of its major pollinators (Meloidae, Tachinidae, Scarabaeidae and Noctuidae) at different altitudes. Our findings show a pronounced altitudinal displacement between the peak abundance zones of S. chamaejasme and its major pollinators, indicating spatial mismatches in both years (2021 and 2022). However, the increased preseason thermal accumulation in 2022 improved spatial matching, as high-density overlap zones shifted to higher altitudes, where insect visitation rates also increased. Additionally, the elevated preseason heat significantly advanced flowering phenology at high altitudes, which may contribute positively to breaking the altitudinal distribution limits of S. chamaejasme, along with enhanced spatial matching with pollinators. This study highlights the significant impact of inter-annual climate variability on spatial matching between mountain plants and pollinators at various altitudes, which is crucial for improving population dynamics models and enhancing the accuracy of predictions.

Tree species diversity is widely assumed to correlate positively with structural complexity in forests, as differences in crown architecture among species enhance structural complexity through physical complementarity. While this complex-diversity relationship has been confirmed experimentally, it frequently weakens or reverses in natural forests. The mechanisms underlying this inconsistency remain unclear. We used the field measurements and drone-derived LiDAR data from the Tiantong 20-ha forest community in eastern China to calculate tree species diversity and forest structural complexity. To assess the mechanism driving the complex-diversity relationship, we calculated stand density and canopy height. Based on these measurements, we tried to answer the following questions: (i) What is the relationship between structural complexity and species diversity in the forest plot? (ii) How stand density or canopy height mediates the interplay between structural complexity and species diversity? (iii) When controlling for stand density and canopy height effects, would a positive complexity-diversity relationship be revealed? We revealed that canopy height and stand density jointly mediate the observed negative complexity-diversity relationship: tall canopies reduced understory species diversity via shading, disproportionately excluding shade-intolerant species; while high stand density suppressed structural complexity, possibly by limiting vertical branching. When these mediating variables were statistically controlled for, a positive complexity-diversity relationship emerged. Our findings, therefore, resolve the apparent inconsistency by demonstrating that structural complexity and diversity inherently facilitate mutual reinforcement in natural forests, but confounding factors like canopy height and stand density may mask this relationship.

The allometric partitioning theory (APT) and optimal partitioning theory (OPT) emphasize the roles of plant size and resource constraints in shaping the adaptive strategies of plants growing under diverse environmental conditions. However, the relative importance of APT and OPT in explaining adaptive strategies is still uncertain. This study selected a region within the same latitudinal zone but spanning a large elevational gradient (2350 m). We conducted systematic sampling of Artemisia species across eight distinct slopes. Biomass data for roots, stems, leaves, and whole plants were measured from 620 individual specimens. Using closely related and widely distributed species is feasible for validating the APT and OPT theories, as it not only minimizes the significant influence of evolutionary differences but also ensures a broad environmental gradient. Based on the above-mentioned measurements, we found that there was a significant allometric relationship between the biomass allocation and the whole plant size of Artemisia species. However, after accounting for size effects, organ allocation ratios still showed significant responses to elevation and environmental principal components. In particular, stem-to-root ratios consistently decreased with increasing elevation across life forms and most species. Structural equation modeling further revealed that elevation influenced biomass allocation indirectly by altering environmental variables (PC1 and PC2). Our findings provide rare empirical support for the simultaneous operation of APT and OPT. Allometric rules offer a baseline. This baseline is adaptively fine-tuned in response to environmental gradients. We stress the importance of integrating both theoretical frameworks. It can help improve predictions of plant biomass allocation strategies under changing environments.

Taxus has unique survival adaptability and climate sensitivity, reflecting the evolutionary characteristics of gymnosperms. It is also an indicator species threatened by climate change, with the most representative endangered species. Because it is the only plant in nature that can naturally synthesize Taxol, it has attracted wide attention. However, the global distribution pattern of Taxus and its climate response mechanisms remain unclear. Moreover, the quantitative absence of key driving factors severely restricts the precise formulation of conservation strategies. Here, we provide the first comprehensive climate impact assessment for Taxus on a global scale. Patterns and driving mechanisms of species richness distributions were predicted using stacked species distribution models. Results showed high species richness regions concentrated in southern Asia and central Europe, and a clear unimodal pattern with a latitudinal gradient (20 °N – 60 °N). Precipitation of the driest quarter (> 14 mm) was a critical determinant of survival, while the aridity index indicated preferences for sub-humid to humid zones. The minimum temperature of the coldest month (> – 15 °C) was a dominant factor accelerating range shifts; under the SSP5-8.5, migration distance (+ 70 km) and range loss (– 58.2%) increased significantly. Species richness loss hotspots included southern North America, eastern/southwestern Europe, and Southeast Asia, with Taxus baccata, Taxus cuspidata, and Taxus brevifolia facing the highest extinction risk. At the same time, wildfires and overgrazing will further exacerbate the loss of area in species richness hotspots, especially for Taxus cuspidata and Taxus wallichiana. Targeted conservation management of endangered species is urgently needed to maintain sustainable biodiversity development.

Xanthium italicum is a globally distributed invasive weed that causes significant ecological and agricultural damage in the invaded areas. Although multiple mechanisms have been reported to contribute to its invasive success, the extent to which intraspecific differentiation and phenotypic plasticity facilitate this process in invaded habitats remains insufficiently understood. In this study, we conducted a common garden experiment with three nitrogen treatments: no nitrogen addition (NN), low nitrogen (LN: 2 g urea per pot), and high nitrogen (HN: 4 g urea per pot). Ten populations of invasive X. italicum (ten individuals per population, 100 individuals total) and native Xanthium sibiricum (excluded from the NN treatment due to seed limitations) were grown under each nitrogen treatments. Under the NN treatment, we detected significant phenotypic differences among different invasive X. italicum populations across six growth traits (root length, shoot length, crown breadth, base diameter, relative chlorophyll content, and biomass). Furthermore, when subjected to the LN and HN treatments, invasive X. italicum exhibited significantly higher phenotypic plasticity compared with that of native X. sibiricum in biomass and base diameter. Our findings suggest that phenotypic plasticity and intraspecific differentiation may play important roles in facilitating the invasive success of X. italicum in China, potentially increasing the risk of further biological invasion.

Mixed cultivation of Larix gmelinii and Juglans mandshurica is a typical strategy for increasing stand productivity in Northeast China. However, the adaptive strategies of fine roots and root-associated fungi (RAF) after mixed cultivation remain unclear. Here, we examined the chemical, morphological and anatomical characteristics of fine roots, along with the composition, diversity and co-occurrence network structure of their RAF communities. Our results showed that mixed cultivation increased the root diameter and root tissue density of first-order to third-order fine roots for both L. gmelinii and J. mandshurica but decreased the specific root length. The root economic spectrum of the two species demonstrated a shift from a ‘do-it-yourself’ strategy to an ‘outsourcing’ strategy in their first- and second-order roots after mixed cultivation. Arbuscular mycorrhizal fungi and endophytic fungi were the main fungal functional groups within the RAF of J. mandshurica, while ectomycorrhizal fungi were dominant in those of L. gmelinii. Mixed cultivation increased the RAF alpha diversity of J. mandshurica but decreased the RAF alpha diversity of L. gmelinii. Negative correlations in the co-occurrence networks of the RAF communities accounted for >50% of the two species, indicating that competitive relationships dominated within the RAF community. Changes in the composition of RAF after mixed cultivation effectively supported shifts in the root economic spectrum of the two species. The coordinated changes in fine root systems and their associated mycorrhizal fungi enable the two species to maintain their competitive edge in nutrient absorption when they are planted together.

Tree species diversity has been found to promote soil organic carbon (SOC) in forests, but its effects on SOC stability have been poorly studied. Using a six-year-old forest biodiversity experiment with monocultures and mixtures of two, four, and eight tree species, we specifically evaluated how functional diversity (FDis) and community-weighted mean (CWM) of leaf nutrients influence the formation of mineral-associated organic carbon (MAOC) via altering the soil microbial community. We found that FDis of leaf nitrogen (LN_mass) and phosphorus (LP_mass) contents, as well as CWM of LP_mass were negatively associated with MAOC, patterns that were mediated by microbial biomass. In addition, CWM of LN_mass was negatively associated with the MAOC:SOC ratio, a relationship mediated by a decrease in the ratio of fungal to bacterial biomass (F:B ratio), while CWM of LP_mass exhibited a direct positive effect on the MAOC:SOC ratio. We also found that soil nutrient availability mediated the relationship between the diversity of leaf nutrients on the soil microbial community. Our results suggested that the diversity of leaf nutrient contents may shape SOC stabilization through moderating microbial biomass and F:B ratio, offering insights into the ecological importance of plant chemical traits in driving SOC stabilization in forest ecosystems.

Leaf chemistry plays a central role in structuring phyllosphere microbiomes. Plant populations often evolve genetic differences in leaf chemistry across region due to both abiotic and biotic selection pressures, including insect herbivory. Plants in invasive populations may reassociate with native specialist insects, providing an ideal system to examine how herbivory-mediated changes in plant chemistry affect phyllosphere microbiome. Here, we conducted a common garden experiment using Ambrosia artemisiifolia populations differing in leaf chemistry and reassociation history with a specialist beetle—Ophraella communa. We found that plant populations with a longer reassociation history exhibited stronger herbivore resistance and supported phyllosphere communities with higher alpha diversity and more complex composition. These changes were associated with shifts in concentrations of plant metabolites and the expression levels of corresponding biosynthetic genes. The abundance of the fungal pathogens, Golovinomyces, decreased with increasing herbivore resistance, while Pestaliopsis showed the opposite trend. Although reassociation history was linked to population latitude, climatic and soil conditions at the sites of origin also contributed to between-population variation in leaf chemistry and phyllosphere fungal community composition. Our study suggests that genetic differences in leaf chemistry among plant populations can strongly affect herbivore resistance and phyllosphere fungal communities. The observed alignment of reassociation history, chemical traits and phyllosphere fungal communities suggests that herbivore-mediated selection may be a key driver of microbial community evolution in invasive plants.

Grazing affects plant carbon sequestration and nutrient cycles, changing the carbon (C), nitrogen (N) and phosphorus (P) stoichiometry in grassland ecosystems. However, the effects of grazing intensity on fine-root C:N:P stoichiometry in alpine meadows remain unclear. Here, we examine how grazing intensity influences the fine-root C:N:P stoichiometry in Tibetan alpine meadows. We conducted a long-term (9 years) experiment on the effects of four grazing intensities (ungrazed, light, moderate and heavy grazing) on an alpine meadow on the eastern Tibetan Plateau. Light and moderate grazing increased fine-root C and N concentrations and the N:P ratio, but decreased the C:N ratio, whereas heavy grazing had no effect on C:N:P stoichiometry. The fine-root C:N:P stoichiometry differed among the plant functional groups at different grazing intensities. In addition, grazing intensity indirectly affected fine-root C:N:P stoichiometry by changing aboveground biomass (AGB) and soil physicochemical properties. Overall, we found that grazing intensity regulated fine-root C:N:P stoichiometry in alpine meadows by changing AGB and soil physicochemical properties. Our findings have important implications for improving alpine meadow ecosystem protection by implementing sustainable grazing intensities on the Tibetan Plateau.

Microbial carbon use efficiency (CUE), a critical determinant of soil carbon cycling, exhibits spatiotemporal variations influenced by biotic and abiotic factors; however, interplay between forest type, seasonality, and fungal community dynamics remains poorly understood. Here, we investigated CUE patterns, soil enzyme activities, and fungal functional guilds across coniferous (Picea asperata, Larix gmelinii) and broadleaved (Betula albosinensis, Quercus aquifolioides) forests in subalpine China during early-, mid-, and late-growing seasons. The CUE of coniferous forests exhibited pronounced seasonal declines (45% reduction in September vs. May–July), whereas broadleaved forests maintained stable. Forest type caused small changes in CUE across seasons, with broadleaved was higher than coniferous forests in late-growing season. Soil fungal community composition diverged significantly between forest types: symbiotroph (mainly ectomycorrhizal fungi) dominated in coniferous soils (58%–81% relative abundance), correlating negatively with CUE, while saprotroph prevailed in broadleaved forests (21%–43%), showing positive CUE associations. Co-occurrence network in broadleaved forests had higher modularity and connectivity than coniferous forests, indicating greater resistance to seasonal variations. Structural equation modelling identified fungal guilds, soil C:N ratio, enzyme investment as primary drivers of CUE variation, with fungal composition mediating 28% CUE variability. Our findings highlight the critical role of fungal functional traits in modulating microbial metabolic efficiency and provide mechanistic insights for predicting soil carbon dynamics in forest ecosystems.

Tree planting is widely recognized as an effective strategy for enhancing terrestrial carbon sequestration, playing a crucial role in mitigating global climate change. However, our understanding of how it may affect soil fauna communities remains scarce. Here, we performed a global meta-analysis with 14 281 paired observations to evaluate tree planting effects on soil fauna abundance, biomass, and diversity across multiple former ecosystem types. Results showed that (i) tree planting had limited overall effects on soil fauna communities, only increasing Acari abundance, Protozoa abundance and Arthropod biomass by 36.9%, 56.9% and 777.3%, respectively, and decreasing the taxonomic richness of Collembola, the Pielou index of earthworm, and the Simpson index of Protozoa by 17.9%, 38.7%, and 77.1%, respectively; (ii) afforestation in non-forest lands showed strong positive effects on soil fauna abundance and diversity, especially in deserts where the abundance and Shannon-Wiener index of total soil fauna were increased by 92.5% and 65.8%, respectively, while reforestation in former forest lands generally had negative impacts; and (iii) tree planting effects on soil fauna were mediated by stand characteristics (e.g. stand age, canopy density, tree diameter) and pre-planting soil properties (e.g. bulk density, pH, carbon, nitrogen), but not by tree species type (leaf type or mycorrhizal association). These results demonstrate the contrasting effects of tree planting on soil fauna communities among different former ecosystem types, highlighting the importance of considering the legacy of former ecosystems when designing tree planting policies to restore/enhance carbon sequestration and biodiversity conservation under global environmental change scenarios.

Due to global change, the dominance of ectomycorrhizal (ECM) tree species is continually decreasing in temperate forests, which is expected to greatly alter soil carbon and nitrogen dynamics. However, the specific mechanisms through which ECM tree dominance affects soil carbon and nitrogen, particularly via regulating above- and belowground forest properties, remain poorly understood. Here, we investigated the relationships of forest above- (e.g., tree species richness and basal area, leaf nutrient content) and belowground properties (e.g., soil microbial community, enzymatic activity) with soil organic carbon (SOC) and nitrogen along an ECM tree dominance gradient in a temperate forest. We found significant changes in above- (i.e., leaf nutrient content, basal area) and belowground (i.e., fungal community, enzymatic activity) forest properties along the ECM tree dominance gradient. For instance, tree basal area and saprotroph abundance increased with ECM tree dominance, while leaf nitrogen content and enzymes related to soil carbon or nitrogen (β-1,4-glucosidase, cellobiohydrolase, β-N acetylglucosaminidase) decreased. Notably, structural equation modeling suggested that ECM tree dominance negatively affected SOC through regulating aboveground properties. However, ECM tree dominance affected soil nitrogen content and transformation rates by regulating both above- and belowground properties, highlighting different pathways through which soil nitrogen vs. SOC respond to ECM tree dominance change. Therefore, ECM tree dominance can affect soil carbon and nitrogen by distinctively regulating above- and belowground forest properties, and both above- and belowground changes should be considered when predicting how temperate forests will respond to the global-change-induced decline in ECM tree dominance.

Spring frost involves low temperatures in spring. Research shows cold snaps can alter herbaceous plants' biomass allocation, impacting grassland ecosystems. However, the exact effects of frost timing and severity remain unclear. This study simulated spring frost based on characteristics of spring frost on the northern slope of the Tianshan Mountains to examine how alfalfa (Medicago sativa) and ryegrass (Lolium spp.) adjust biomass allocation under varying frost intensities and timings, including interspecific differences in these responses. The findings revealed that (1) compared to the control group (which did not undergo low-temperature treatment), alfalfa was more sensitive to high-intensity spring frost, exhibiting a significant decrease of 13.6% in the root weight ratio and increases of 8.65% and 4.96% in the stem and leaf weight ratios, respectively. In contrast, ryegrass displayed an inverse trend, although the changes were not significant. (2) Early stage spring frost (immediately after thinning) significantly affected alfalfa biomass allocation, leading to an 11.28% decrease in the root weight ratio, whereas it also significant increases of 3.78% the stem weight ratio by 7.51% and leaf weight ratio. In contrast, late stage spring frost (applied on the 17rd day after thinning) had a relatively greater effect on ryegrass, with the root weight ratio increasing by 4.13% and the stem weight ratio decreasing by 4.18%. These findings reveal plants' distinct adaptations to cryogenic stresses, improving our understanding of herbaceous growth responses to extreme weather in arid zones and offering data to support grassland ecosystem services in Xinjiang.

Leaf economic, hydraulic and anatomical traits play crucial roles in plant adaptation to diverse and variable environments. However, their relationships at the intraspecific level remain unclear. In this study, we investigated Quercus variabilis, a species spanning temperate to subtropical zones, to assess functional trait variation along a north-to-south environmental gradient in China (24°94′–40°26′ N). We analyzed 10 key functional traits, including leaf mass per area (LMA), leaf thickness (LT), leaf tissue density (LTD), leaf nitrogen concentration (LN), stomatal density (SD), vein density (VD), stomatal guard cell length (SL), palisade tissue thickness (PT), spongy tissue thickness (ST) and palisade-to-spongy tissue ratio (PT/ST) across 9 natural populations. The results showed that Q. variabilis exhibited significant plasticity in functional trait variation, primarily driven by environmental factors, with mean annual precipitation (MAP) and soil total nitrogen (STN) emerging as key ecological drivers promoting the coordinated variation in leaf functional traits. Coordinated relationships were observed between leaf economic traits (LMA, LT, LTD, LN) and hydraulic traits (SD, VD, SL), which varied in response to environmental conditions. Furthermore, leaf anatomical traits (PT, ST, PT/ST) were closely linked to both hydraulic and economic traits. These findings provide valuable insights into the adaptive strategies of Q. variabilis and enhance our understanding of plant responses to environmental change at the intraspecific level.

Alpine cushion plants are recognized as keystone species essential for sustaining plant communities and biodiversity. However, their contributions to the structures of plant–plant co-occurrence networks remain poorly understood. This study constructed plant–plant co-occurrence networks within cushion microhabitats at both regional and local scales in the Himalaya–Hengduan Mountains, focusing on the influences of multiple cushion plants in shaping plant–plant network structures. Results reveal that cushion plants significantly influence the network structures. Compared to random expectations, these networks display lower linkage density, weighted connectance and weighted nestedness (wNODF), but higher modularity, implying distinct organizational principles driven by cushion plant facilitation. Non-cushion plants show stronger associations with cushion microhabitats than with open ground microhabitats. Additionally, the spatial influence of cushion plants extends beyond their immediate canopies, highlighting their role in structuring surrounding plant assemblages. Moreover, the facilitation strength of cushion plants positively correlates with network metrics, indicating that network complexity increases with increasing facilitation by cushion plants. Simulations suggest that the loss of cushion plants would likely trigger cascading extinctions of associated non-cushion plants, particularly when high-degree centrality cushion species—those with the greatest network connectivity—are removed. These results highlight the keystone roles of cushion plants’ facilitation in supporting biodiversity via enhancing network complexity and robustness. Given the vulnerability of alpine ecosystem to environmental disturbances, our study emphasizes the urgent need to prioritize the conservation of cushion plant diversity. Future conservation strategies should adopt an integrated approach that protects not only individual cushion species but also the micro-communities they support.

Invasive plants often generate more positive plant–soil feedbacks (PSFs) than natives. The direction and strength of PSFs have been affected by resource availability and conspecific plant density, but their joint effects on PSFs of invasive plants have not been examined. We conducted a two-phase PSF experiment to examine how soil nutrient availability and planting density affect feedback with soil biota between a community of five invasive Asteraceae plants (two clonal species) and four co-occurring native plants (one clonal species). Soil biota from invaders did not inhibit plant growth, but soil biota from natives did so. The difference in PSFs between geographic origins was most pronounced under high-nutrient and high-density conditions where the biomass of natives in conspecific soils was much lower than that in soils conditioned by heterospecific invaders. Clonality and its inter-actions with nutrient and density did not affect PSFs. Soils from invaders had a higher diversity of arbuscular mycorrhizal fungi, and soils from invaders and natives differed in the composition of pathogenic fungi. Our results may explain why invaders but not natives often form dense monocultural stands. That is, as plants take advantage of increased nutrient supply and conspecific density increases, PSFs change little for invaders, but they change to be highly negative for natives, preventing them from forming dense monocultural stands. This invasion mechanism may be particularly pertinent to clonal invaders, as they can swiftly proliferate within habitats via clonal reproduction without encountering negative density dependence, thus establishing dense monocultural stands rapidly from just a few individuals.

The mechanisms of plant adaptation to environmental gradients have been the focus of ecological research, with environmental stresses driving coordinated or differentiated regulation of plant functional traits. Plant resource acquisition involves root trait plasticity and mycorrhizal symbiosis. However, root trait plasticity along precipitation gradients and root-mycorrhizal trade-offs remain unclear. We conducted community surveys along a west-east precipitation gradient in four natural grassland communities (alpine desert steppe, alpine steppe, alpine meadow steppe and alpine meadow) on the plateau in northern Xizang Plateau. Six key root traits (root diameter, RD; root dry matter content, RDMC; root tissue density, RTD; specific root length, SRL; root branching intensity, RBI; and root length colonization percentage, RLC) were measured in 18 alpine plant species to investigate the coordination and trade-offs between root traits and mycorrhizal fungi along the precipitation gradient. Our results showed community-level declines in RDMC, RD, RTD and RLC with increasing precipitation, contrasting with elevated RBI and SRL. Functional groups exhibited distinct patterns: grasses and legumes demonstrated root-mycorrhizal trade-offs, sedges displayed synergy and forbs showed inconsistent responses. Divergent trends in plant root traits and mycorrhizal fungi were observed at the species level. Alpine plants in humid eastern meadows favored root elongation, while those in arid western desert steppe relied on radial growth and mycorrhizal fungal cooperation for resource acquisition. These findings highlight varied root absorption strategies among alpine plants along environmental gradients, supporting the importance of ecological niche diversification in maintaining alpine ecosystem diversity and stability.

Trait-based functional diversity (FD) is an important predictor of tree species ecological multifunctionality (TS-EMF), but its relationship may be mediated by environmental factors. Currently, the study of threshold-dependent relationship between FD and TS-EMF along urban and suburban gradients and their environmental regulatory mechanisms is still quite limited. In this study, 12 typical tree species from urban and suburban forests in Shenyang were used to calculate TS-EMF by combining the multithreshold and averaging method, and to assess community FD, aiming to reveal the role of FD on TS-EMF and how environmental factors regulate TS-EMF through FD and community-weighted mean (CWM) traits. The results showed that urban TS-EMF was generally higher than suburban (P < 0.05). There were differences in the driving mechanisms of TS-EMF at different threshold levels, with air humidity (total effect: 0.435) and CWM P_n (net photosynthetic rate, relative importance: 24.42%) being the key drivers at high threshold levels. At low threshold levels, functional evenness (FEve) played a dominant role, but the extent to which influenced TS-EMF depended on the type and number of tree species within the TS-EMF threshold range. Notably, the effects of CWM P_n and FEve on TS-EMF showed threshold dependence, with thresholds of 61.18% and 64.47%, respectively. Additionally, the urban–suburban gradient could significantly influence the driving mechanism: the direct effect of environmental factors and CWM traits prevailed in urban forests, while suburban forests showed a multifactorial cascade effect. The study showed that the formation of TS-EMF in urban forests is the result of multifactorial coupling of traits, FD and environmental factors, and this finding provides a new theoretical perspective for understanding the ecosystem service drivers of urban forests.

While plant root exudates play a crucial role in regulating soil microbial communities, their complex composition, low concentration and degradability make it difficult to determine their effects on microbial biomass, diversity and structure. In this study, we integrated 3174 observations from 121 publications to systematically assess the effects of root exudate addition on soil microbial communities and their differential response mechanisms. The results indicated that exudates significantly increased microbial biomass (total microbial biomass: +18.65%; bacteria biomass: +31.35%; fungi biomass: +37.73%) but decreased α-diversity (−6.17%), richness (−9.16%) and evenness (−10.09%), while also altered the community structure. Natural exudates, with their complex composition and higher nutrient content, had a stronger effect on promoting microbial biomass, whereas synthetic exudates led to the overgrowth of certain bacterial taxa, suppressing microbial community diversity. The responses of soil available nitrogen content were identified as key predictors of microbial biomass, while soil pH was an important predictor of microbial richness and evenness. Meanwhile, the carbon input rate from root exudates significantly suppressed α-diversity and altered microbial community structure. Additionally, the C:N ratio of exudates played a critical role in regulating β-diversity and community structure. This study highlights the importance of exudate chemical properties, experimental conditions and soil physicochemical characteristics, offering a new perspective on the mechanisms regulating microbial communities by root exudates.

Drought is one of the major abiotic stresses that limits plant growth. Roots, the primary organs responsible for water uptake, are the first to perceive and respond to water deficit conditions. Therefore, maintaining activity and promoting primary root elongation under drought stress are considered critical adaptive strategies for drought survival. However, despite increasing evidence of primary root elongation under drought stress, the underlying mechanisms, particularly hormonal regulation and its integration with environmental cues, remain poorly understood across different species and developmental contexts. Previous studies have shown that a highly coordinated network of plant hormone crosstalk plays a significant role in this adaptive process. In this review, data from diverse plant species confirmed the promoting effect of drought on primary root growth. This study further elucidated the role of abscisic acid (ABA) in enhancing primary root growth under drought conditions and explored the potential coordination of ABA with other hormones, including ethylene, auxin, and cytokinin, to synergistically promote primary root elongation. Furthermore, several physiological processes, such as cell cycle regulation, osmotic adjustment, and lateral root growth dynamics, had been systematically investigated for their contributions to this adaptive response. By dissecting these mechanisms, this study aims to propose feasible strategies to increase plant drought tolerance through targeted root system architecture modification, addressing challenges posed by future climate scenarios.

Artificial light at night (ALAN) is an emerging component of global change and may increase the risk of plant invasion. However, the effects of different intensities of ALAN on the growth of invasive and native plants remain unclear. We conducted a controlled experiment in which five pairs of invasive and native plants from different families were grown separately under three light regimes: ambient light, low ALAN, and high ALAN. Our study showed that the total biomass of both invasive and native plants increased significantly under low-intensity ALAN. However, under high-intensity ALAN, the total biomass of invasive plants increased significantly, whereas the biomass of native plants significantly decreased. These findings indicate that invasive plants can better utilize light energy and have more effective photosynthetic responses under ALAN, while the photosynthesis of native plants is inhibited. The leaf dry matter content and leaf nitrogen content of invasive plants were significantly higher than those of native plants under ALAN, which significantly improved the photosynthetic nitrogen use efficiency of invasive plants. This indicates that invasive plants have stronger phenotypic plasticity and nitrogen-distribution strategy under ALAN. In summary, the enhanced physiological response of invasive plants under different intensities of ALAN may contribute to their continued spread and dominance in the ecosystem.

In grassland ecosystem management, mowing influences the tolerance mechanism of plants by modifying their growth and reproductive traits; however, the specific processes involved remain unclear. This study focused on the Elymus species (Elymus nutans ‘Aba’, Elymus sibiricus ‘Qingmu No.1’, Elymus submuticus ‘Tongde’, Elymus breviaristatus ‘Tongde’ and E. sibiricus ‘Tongde’) and systematically evaluated the effects of different mowing intensities (no mowing, light, moderate and heavy mowing) at three growth stages (jointing, booting and flowering) on plant tolerance and the role of growth and reproductive traits in this mechanism. The results revealed that mowing generally reduced plant height and the reproductive branch quantity, while significantly increasing the tiller number, seedling number and relative growth rate. However, the responses of rhizome length and vegetative branch height varied across the growth stages. Mowing during the jointing stage had the most significant effect on morphological traits, with vegetative reproduction contributing the most to tolerance and increasing with mowing intensity. Overall, the plant response to mowing timing was more pronounced than its response to changes in individual traits. Moderate mowing at the jointing stage significantly increased growth rate, tiller number and seedling number, thereby enhancing mowing tolerance. In contrast, heavy mowing at the booting and flowering stages markedly reduced reproductive branch quantity and rhizome length, resulting in diminished mowing tolerance. The study indicated that differences in the mowing stage and forage species regulated adaptive changes in growth and reproductive traits, thereby influencing tolerance mechanisms. Grassland management should fully consider the effects of mowing at different growth stages to optimize the utilization and management of the Elymus grasslands.

Effects of climate warming on plant phenology have garnered significant attention in recent decades. However, the distinct and interactive effects of warming during growing and non-growing seasons on plant phenology remain unclear. Here, we aimed to study how seasonal climate warming influences plant phenology in a temperate steppe. Seasonal warming experiment was conducted in Inner Mongolian steppe using open top chambers. Flowering and fruiting times of six dominant species were observed from 2019 to 2020. Interactive effects between growing-season and non-growing-season warming on plant phenology were analyzed using linear mixed-effects models. Growing-season warming advanced the flowering and fruiting onset time, thereby extending the duration of both reproductive phases across the six monitored species. In contrast, non-growing-season warming delayed fruiting onset time by 1.8 days but did not affect flowering time. Growing-season and non-growing-season warming interactively affected the onset time and duration of fruiting. Specifically, growing-season warming advanced the fruiting onset time by 3.9 days and extended the fruiting duration by 5.8 days in the absence of non-growing-season warming. However, growing-season warming only advanced fruiting onset time by 1.4 days and extended fruiting duration by 1.6 days under non-growing-season warming conditions. These phenological shifts were primarily driven by changes in air temperature and plant height. Our experiment provides clear evidence for the distinct and interactive effects of growing-season and non-growing-season warming on plant phenology, offering valuable insights for predicting future changes in terrestrial ecosystem processes under future global warming scenarios.

The intricate relationships between plants and their rhizobacteria are crucial for plant success, yet our understanding of these associations, particularly in diverse alpine natural grasslands, remains limited. Here, we investigated two widespread grass genera (Stipa Linn and Poa Linn) and their core rhizobacteria across a vast 2161 km transects on the Qinghai–Tibetan Plateau. Compared to Stipa L., which has a broader niche breadth, Poa L. displays higher above- and below-ground biomass. This characteristic reflects a more resource-conservative and stable growth strategy, consistent with traits commonly observed in K-strategists. However, Poa’s core rhizobacteria (5458 species, 9.51% of total amplicon sequence variants (ASVs)) were enriched with here r-strategists, while Stipa’s (5193 species, 9.05% of total ASVs) were dominated by K-strategists. These findings highlight contrasting life-history strategies between grasses and their associated core rhizobacteria. Notably, only 633 core rhizobacteria overlapped between these two grasses. Functionally, Poa’s r-strategist microbiota likely prioritizes rapid resource acquisition for high biomass production, while Stipa’s K-strategist-dominated community might enhance stress tolerance in their resource-limited habitat. The observed pattern of life-history differences between grasses and rhizosphere microbes supports plant survival in alpine ecosystems. Our study advances understanding of rhizosphere ecology and its importance for ecosystem health in natural environments.

The home-field advantage (HFA) hypothesis predicts that litter decomposes faster in its home environment than elsewhere. Given the critical role of HFA effect in mediating terrestrial carbon and nutrient cycling, it remains unclear how nitrogen (N) deposition affects this effect. Here, we conducted a 12-month field experiment involving reciprocal litter translocation, with four N addition levels (0, 30, 50 and 100 kg N ha^–1 year^–1), in Quercus acutissima and Pinus massoniana stands in a subtropical urban forest and a mini meta-analysis of the effect of N addition on HFA in global forests. Results showed that a significant positive HFA of 3.98 was observed, but N addition (particularly with high rates) tended to weaken it, by decreasing it to –6.12 at 100 kg N ha^–1 year^–1. Conversely, the combined HFA index increased with bacterial community dissimilarity between stands. Such relationships were due to that N addition changed soil bacterial diversity and composition in P. massoniana stand and led to the convergence of bacterial communities between stands, mainly by lowering soil pH. Similarly, our experiment and meta-analysis showed that the species-level HFA index and its response to N addition also decreased with N addition rate (P < 0.05), suggesting the generalization of how N addition affects HFA. Our findings suggest that soil acidification driven by N inputs indirectly reduces HFA through altering bacterial communities, which helps to better understand and predict the dynamics of HFA effect and the cycling of carbon and nitrogen in forest ecosystems under N deposition.

Grazing exclusion through fencing is widely used for vegetation restoration in degraded alpine meadows. However, the dynamic responses of plant communities to grazing exclusion remain poorly understood, especially from an integrated perspective of species diversity, niches, and interspecific associations. In this study, we investigated four proximate alpine meadows on the Tibetan Plateau with different fencing durations (0, 2, 6, and 12 years). We assessed the responses of plant diversity, niche characteristics, and interspecific associations to fencing duration, along with relationships among these dimensions. The results showed a unimodal response of plant diversity to fencing duration, with the Patrick richness index varying in coordination with niche and interspecific association metrics. After 2 years of fencing, the community niche breadth expanded, accompanied by increased niche overlap and Ochiai association index among major species. By 6 years of fencing, the niche breadth shifted toward lower values, and niche overlap of major species decreased significantly, with the proportion of species pairs with high overlap and high association reduced by 21.95% and 25.93%, respectively. After 12 years of fencing, niche overlap rebounded significantly, and the proportion of species pairs with high niche overlap and high association increased by 18.79% and 16.84%, respectively. Our findings support identifying 6 years of fencing as a critical intervention point. At this stage, the community achieves a dynamic balance between competition and coexistence through niche differentiation, maintaining high species diversity. We suggest moderate disturbance should be implemented in alpine meadows thereafter to prevent retrogressive succession.

Alien plants exhibit varied performance and distribution patterns across latitudinal gradients depending on species invasiveness and target community invasibility. Although numerous researches have studied the latitudinal patterns of plant invasiveness, few have focused on community-level invasibility. We hypothesize that community invasibility increases with latitude due to a reduction in native species richness (diversity-resistance hypothesis) and stronger environmental filtering (pre-adaptation hypothesis) at higher latitude. We conducted a field survey at 18 sites across 6 latitudes in southeast China to explore how the community invasibility changes with latitude and identify the key drivers underlying these patterns. We found that the community invasibility positively correlated with latitude, primarily due to a decrease of native species diversity at higher latitude. Climate factors exerted indirect effects on community invasibility by shaping native species diversity. The mean pairwise phylogenetic distance between species did not change with latitude indicating minor effects of pre-adaptation. Our study emphasizes the importance of native species diversity in shaping latitudinal patterns of community invasibility. These findings highlight biodiversity conservation as an effective strategy to mitigate biological invasions, particularly in regions vulnerable to climate change.

Litsea coreana Levl. var. sinensis has developed four heteromorphic leaf types to adapt to the local environment. This study investigated functional traits of four heteromorphic leaf types associated with leaf morphology, anatomy, photosynthesis, and activity compounds, to elucidate their niche differentiation within a single tree. Lanceolate (La) type had the largest leaf length (LL = 8.4 cm), leaf shape index (LSI = 2.8), leaf perimeter (LP = 18.5 cm), but low palisade tissue thickness (TPTT), light saturation point (L_SP), and light compensation point (L_CP), allowing them suited for varied positions and mild, humid climates. Ovoid (Ov) and orbiculate (Or) types had highest leaf thickness (LT = 0.2 mm) and high TPTT (66.9 and 63.9 μm), high chlorophyll (0.695 and 0.696 mg g⁻¹), high net photosynthetic rate (P_Nmax = 8.1 and 6.6 μmol m⁻² s⁻¹), high total flavonoid content (TFC = 45.2 and 47.7 mg g⁻¹), indicating their adaptation to top and edge canopy positions with high temperatures and light conditions. Oblanceolate (Ob) type had largest SLA (117.2 cm² g⁻¹) and high dark respiration rate (R_d), but low TPTT and chlorophyll, which is important for shade adaptation in the lower canopy. Overall, LSI increased with the increases of LL, the higher value of TPTT, the greater value of P/S (Palisade/Spongy) was observed, and as the increases of L_SP, P_Nmax gradually increased. Three principal components were extracted with a cumulative contribution of 75.2%, of which the Ov type had the highest value. Our findings provided evidence that the presence of heteromorphic leaf types facilitates the utilization resources of different microhabitat by L. coreana Levl. var. sinensis.

As important components of soil organic carbon (SOC), soil amino sugars and lignin phenols serve as reliable biomarkers for microbial- and plant-derived C, and their relative contents provide critical insights into the SOC composition and stability. However, the dynamic changes of soil amino sugars and lignin phenols with restoration time in the widely planted subtropical Castanopsis hystrix plantations remain unclear, which limits the development of scientific management strategies. Here, we analyzed soil amino sugars, lignin phenols and the related biotic and abiotic factors at two soil depths (0–10 cm and 20–30 cm) across various stand age of Castanopsis hystrix plantations in southern China. The results showed a divergent accumulation of soil amino sugars and lignin phenols with stand age, in which the ratio of soil amino sugars to SOC exhibited a unimodal pattern with stand age in the topsoil (0–10 cm), while the ratio of soil lignin phenols to SOC decreased with stand age in both soil depths. Consequently, the ratio of soil amino sugars to lignin phenols increased with stand age, particularly in the subsoil (20–30 cm). Further analysis indicated that the divergent accumulation of soil amino sugars and lignin phenols with stand age was mainly related to changes in the litter biomass and quality, while the divergence with soil depth was primarily driven by microbial residue formation efficiency. These findings demonstrate the SOC composition shift from plant-derived C to microbial-derived C during plantation restoration, offering important implications for forest management practices and nature-based climate solutions.

Groundwater depth is a key environmental factor influencing the composition and structure of plant communities in coastal ecosystems. However, effects of the groundwater depth on the characteristics of shrub-grass communities in muddy coastal zones remain poorly understood. In this study, we conducted a field experiment to evaluate effects of the different groundwater depth (0.54, 0.83, 1.18, 1.62, and 2.04 m), on soil salinity, soil moisture, community diversity, distribution pattern and growth of the dominant Tamarix chinensis in the muddy coastal zone of Bohai Bay. Our results demonstrated that (1) the soil moisture and salinity gradually decreased with increasing groundwater depth (P < 0.001); Compared to the 0.54 m groundwater depth, soil moisture at depths of 0.83, 1.18, 1.62, and 2.04 m decreased by 16.02%, 24.83%, 54.40%, and 61.24%, and soil salinity decreased by 43.17%, 50.82%, 63.93%, and 73.41%, compared to 0.54 m, respectively. (2) The Simpson, Shannon-Wiener, Pielou and Margalef indices of the T. chinensis communities peaked at the 1.62 m groundwater table depth; (3) The dominant shrub T. chinensis population exhibited an aggregated distribution and optimal growth of T. chinensis shrubs occurring within the groundwater table depth range of 1.18 to 1.62 m; (4) The groundwater depth affected the diversity of the plant community primarily by influencing soil salinity rather than soil moisture; the dominant shrub T. chinensis promoted diversity of plant community, but this facilitation effect was inhibited by soil salinity. Our results suggest that the optimal groundwater depth for maintaining biodiversity falls within the range of 1.18 to 1.62 m. Shallow groundwater diminishes biodiversity both directly through soil salinization and indirectly by impairing T. chinensis’ facilitation of biodiversity. Therefore, regulating optimal groundwater table depth and protecting T. chinensis are critical for biodiversity conservation and ecosystem recovery in muddy coastal areas.