Regulatory effects of biological soil crusts on aboveground biomass accumulation of ephemeral plants in temperate desert
Jun Zhang, Chun-Sheng Luo, Xiao-Bing Zhou, Haytham Salem, Ben-Feng Yin, Lei Zhang, Yuan-Ming Zhang
2026, 19 (4): rtag011.
doi:10.1093/jpe/rtag011
Abstract ( 408 )   PDF（pc） (3082KB) ( 18 )   Save
In desert ecosystems, biological soil crusts (biocrusts) play a crucial role in regulating soil nutrient dynamics and plant productivity. However, their cascading effects on aboveground biomass (AGB) mediated through soil-plant-microbe interactions remain poorly understood. To address this gap, we conducted a field experiment in the Gurbantunggut Desert of Central Asia, focusing on Erodium oxyrrhynchum, a dominant ephemeral species. We compared biocrust successional stages (from bare sand to moss crust) and ephemeral plant germination seasons (spring vs. autumn), assessing soil properties, plant traits, and phyllosphere microbial communities. Significant differences in leaf traits and AGB were observed between spring- and autumn-germinated plants across biocrust successional stages. Autumn-germinated plants exhibited higher AGB and more resource-acquisitive traits, whereas spring-germinated plants showed stronger stress tolerance but reduced AGB. AGB declined along the biocrust successional gradient (bare sand > algal crust > lichen crust > moss crust). Structural equation modeling revealed that soil moisture and nutrient availability were the dominant drivers of AGB, followed by phyllosphere microbial composition and plant traits. Biocrusts influenced plant biomass primarily through bacteria-mediated pathways that modified soil conditions. These findings highlight a trade-off between biocrust-driven nutrient enrichment and water limitation, which collectively shape desert ecosystem productivity. These findings also provide a mechanistic foundation for predicting ecosystem responses to environmental change and for developing effective restoration strategies in arid regions.

Exogenous Bacillus promotes enrichment of native microbes to assemble synthetic communities for plant growth promotion
Hui Nie, Jingyi Zeng, Qianqian Liu, Xiongfei Zhang, Lianhao Sun, Jie Lin, Chong Li, Nan Wang, Haidong Li, Xin Liu, Jinchi Zhang
2026, 19 (4): rtag016.
doi:10.1093/jpe/rtag016
Abstract ( 197 )   PDF（pc） (1591KB) ( 51 )   Save
Plants recruit beneficial microbes to support growth and defense, but how exogenous inoculants interact with native microbiomes to influence plant performance remains unclear. We found that Bacillus thuringiensis NL-11 promoted the enrichment of indigenous taxa, including 45 amplicon sequence variants (ASVs). From a nonredundant isolate collection, we linked enriched ASVs to isolates (based on 16S rRNA identity) to build a 12-member SynCom (SynCom12), and adding B. thuringiensis NL-11 produced BSynCom12 to test the growth effects. Neither SynCom12 nor BSynCom12 exceeded the growth promotion of B. thuringiensis NL-11 alone. Therefore, we designed a simplified synthetic community, SynComC, which consisted of two strains (NJ158 and NJ63) with strong rhizosphere colonization capabilities and high abundance with the help of NL-11, and whose growth-promoting ability exceeded that of SynCom12 and BSynCom12. Moreover, coinoculation of B. thuringiensis NL-11 with SynComC yielded the highest stability in bacterial co-occurrence networks. Community assembly analyses further showed that NL-11 alone increased deterministic assembly, whereas NL-11/SynComC coinoculation restored stochastic dominance. Metagenomics revealed an enrichment of plant hormone signaling, plant-pathogen interactions, MAPK signaling and isoflavonoid biosynthesis in the inoculated groups (NL-11, SynComC and BSynComC). Our SynCom assembly strategy, guided by colonization capacity and coinoculation with native partners, effectively promotes plant growth and informs rational design of synthetic communities.

Plant community exhibits stochastic assembly pattern at early stage of vegetation restoration in heavily degraded alpine meadows on the Qinghai-Tibetan Plateau
Yuanming Xiao, Juan Wang, Wenying Wang, Xiaoyun Wang, Xinyu Yang, Bo Fan, Guoying Zhou
2026, 19 (4): rtag004.
doi:10.1093/jpe/rtag004
Abstract ( 163 )   PDF（pc） (1956KB) ( 20 )   Save
Understanding the mechanisms governing plant community assembly is crucial for developing effective vegetation restoration and management strategies. However, studies examining plant community assembly during the restoration of severely degraded alpine meadows remain limited. In this study, we investigated the processes shaping plant community structure and the associated environmental drivers during the early stages of restoration in severely degraded alpine meadows. Our results showed that differences in plant community composition between mixed sowing and control treatments increased over time. Additionally, both species richness and the dominance of forb species originating from the soil seed bank progressively declined. Across all mixed sowing treatments, plant community assembly showed stochastic assembly patterns, with homogeneous dispersal increasing and ecological drift decreasing annually. By the third year of restoration, heterogeneous selection was more pronounced in the grass + legume mixture than in the grass-only and grass + legume + sedge mixture treatments. Further analyses identified under-canopy photosynthetically active radiation intensity and soil available phosphorus as the key environmental drivers of plant community composition. Therefore, we infer that the stochastic assembly observed after mixed sowing arises from the counterbalancing effects of environmental filtering and niche differentiation. This study highlights that reducing soil nutrient availability to limit the dominance of upper-layer plant communities is crucial for maintaining plant species diversity during the early stages of alpine meadow restoration. Overall, our findings provide valuable insights for improving vegetation restoration strategies in degraded alpine grasslands.

Special Issue: Digital Ecology: integrating AI and big data for ecosystem monitoring and management

Spaceborne LiDAR reveals 3D structural differences between natural forests and tree plantations in China
Hao Bai, Asadilla Yusup, Yanpei Guo, Kai Cheng, Xiuzhi Chen, Jing Liu, Shengli Tao
2026, 19 (4): rtag008.
doi:10.1093/jpe/rtag008
Abstract ( 512 )   PDF（pc） (1527KB) ( 74 )   Save
Tree planting has been widely implemented worldwide to restore forest area and ecosystem services. While China has become the world’s largest country in terms of planted tree area, it remains unclear whether these tree plantations approximate the close-to-nature 3D structures that are critical for supporting ecosystem services. Using Global Ecosystem Dynamics Investigation (GEDI) data, in combination with linear mixed model analysis, this study for the first time provided a national-scale assessment of the difference in 3D structure between natural forests and tree plantations in China. We found that natural forests outperform tree plantations in canopy height (ΔRH98 = 0.58 m), foliage height diversity (ΔFHD = 0.06), plant area index (ΔPAI = 0.22), and canopy cover (ΔCover = 0.04). These differences vary across vegetation regions, with the largest ΔRH98, ΔPAI and ΔCover in the Warm Temperate Deciduous Broadleaf Forest Region, whereas the largest ΔFHD was found in the Cold Temperate Coniferous Forest Region. Linear mixed modeling further revealed that ΔPAI and ΔCover decreased under more favorable hydrothermal conditions. Our study revealed structural differences between China’s natural forests and tree plantations, highlighting the importance of selecting suitable sites with favorable environmental conditions for tree plantations and promoting close-to-nature management practice to support their ecosystem services.

Data Paper

Woody plant functional traits of natural karst forests in the Maolan National Nature Reserve, southwestern China
Shu-ming Li, Chen-ling Wang, Xiao-ling Lu, Xiao-yin Guan, Ting-ting Yang, Li-bin Liu, Jian Ni
2026, 19 (4): rtag010.
doi:10.1093/jpe/rtag010
Abstract ( 123 )   PDF（pc） (1490KB) ( 15 )   Save
Plant functional trait databases are indispensable tools in modern ecology and have been widely employed in research on plant life history strategies, community species composition and structural dynamics, and ecosystem responses to environmental change. Karst regions are characterized by complex terrain, high habitat heterogeneity, and unique vegetation types, and each of these environmental factors independently and interactively produce distinctive communities and traits along the landscape. Currently, most investigations into plant functional traits within karst regions have focused exclusively on leaf traits of a small number of dominant species within communities. This narrow focus has resulted in a significant gap in the available data regarding plant functional traits in karst environments. This study presented data on ten morphological traits from 3661 individuals of 152 plant species across 90 genera and 65 families. All individuals had a diameter at breast height of ≥1 cm and were collected from twelve plots in the Maolan National Nature Reserve, southwestern China. Utilizing this database, we analyzed trait correlations and both interspecific and intraspecific variations. Most traits exhibited significant correlations with one another (P < 0.01). Trait variability differed markedly, with twig traits showing lower variation than leaf and bark traits. Intraspecific, interindividual variation described a significant proportion of variation, from 39.42% to 52.49%. This database consolidates extensive plant functional trait data from karst regions, supporting future research on plant adaptive strategies in these unique habitats and improving our understanding of local community assembly and maintenance

Nitrogen input drives C/N stoichiometric shifts and enhances ecosystem productivity in wetlands worldwide
Xueyan Lu, Yuting Zhao, Zhenni Wang, Erina Hangxigud, Qi Jia, Jialu Zhang, Rui Qi, Lu Wen, Frank Yonghong Li
2026, 19 (4): rtag018.
doi:10.1093/jpe/rtag018
Abstract ( 92 )   PDF（pc） (1958KB) ( 6 )   Save
Nitrogen (N) input is one of the key global change contributors that has profound effects on the carbon (C) and N cycling of wetland ecosystems. However, the information is very limited on the response patterns of wetland productivity to N input-induced changes in elemental stoichiometric composition. Here we investigated the effects of global N input on the stoichiometry and productivity of wetland ecosystems using 103 individual data points from 74 studies. The results showed that global N input significantly enhanced wetland aboveground and belowground productivity by 45.5% and 21.7%, respectively. N input significantly altered C and N content of plant, soil and microbes: C content increased significantly in plant roots (4.9%), soil (4.8%), and microbes (29.3%), but decreased significantly in plant stems (0.8%); also, C content in plant leaf tissue showed no significant change. While N content increased significantly in all components. N input generally enhanced wetland productivity and reduced C:N ratios across ecosystem components, but its effect intensity was modulated by multiple environmental factors. More critically, statistical analysis revealed that changes in C/N stoichiometry in plant stems—rather than in plant leaves or roots—constituted the core mechanism linking N input to wetland productivity responses. This mechanism explained 31.0% and 56.3% of the variation in above-ground and below-ground productivity, respectively. Our meta-analysis shows that plant stems stoichiometry under N input is key factor to wetland productivity. These responding processes contribute to a better understanding of the N input induced changes in wetland productivity, and improve ecosystem modeling.

Compound droughts dominated the reduction of vegetation productivity in China from 1982 to 2018
Jia Liu, Zelin Liu, Xiaolu Zhou, Peng Li, Tong Li, Cong Liu, Ziying Zou, Jiayi Tang, Cicheng Zhang, Changhui Peng
2026, 19 (4): rtag021.
doi:10.1093/jpe/rtag021
Abstract ( 153 )   PDF（pc） (2610KB) ( 17 )   Save
Global warming has increased the frequency and spatial extent of droughts, disrupting vegetation growth through atmospheric and soil pathways. Compound droughts have more complex and severe impacts on vegetation than individual droughts and have recently received widespread attention. However, the response of vegetation to individual droughts is controversial, and the contribution of compound droughts to vegetation productivity remains unclear. This study defined atmospheric, soil, and compound droughts based on vapor pressure deficit and soil moisture, and investigated their trends in China from 1982 to 2018 using piecewise linear regression. Using gross primary productivity products derived from the Global Land Surface Satellite (GLASS_GPP) and the Near-Infrared Reflectance of Vegetation (NIRv_GPP), drought impacts on GPP were quantified to identify the dominant factor in GPP reduction. All three drought types showed significant increasing trends with turning points in 1998 and 2009 and were negatively correlated with GPP. From 1998 to 2009, drought frequency increased most, with GLASS_GPP (–2.02 g C m^–2 yr^–1) and NIRv_GPP (–0.90 g C m^–2 yr^–1) declining most sharply, mainly in North China, Southwest China, and Central China. Although the negative impacts of all drought types intensified over time, compound droughts were identified as a major contributor to GPP reduction in China. While the influence of other factors may vary regionally, our results provide new evidence highlighting the prominent role of compound droughts in driving declines in vegetation productivity and offer valuable insights for assessing their impact on future terrestrial carbon uptake.

Tree diversity promotes crown complementarity and canopy packing through variation in architecture traits
Muhammad Abdullah, Li-Ting Zheng, Li Zhang, Bai-Yu Yang, Samreen Ghulam Rasool, En-Rong Yan
2026, 19 (4): rtag025.
doi:10.1093/jpe/rtag025
Abstract ( 99 )   PDF（pc） (3323KB) ( 12 )   Save
Crown complementarity and canopy packing are key drivers of tree diversity effects on ecosystem productivity. Tree architecture is an important determinant of height extension, light capture and crown development in trees, but how architectural traits mediate the effects of tree diversity on crown complementarity and canopy packing remains unclear. Here, we examined how the effects of tree diversity on crown complementarity and canopy packing are directly and indirectly mediated by variation in architectural traits in a tree diversity experiment on Putuo Island in eastern China. The results showed that tree species richness and functional diversity increased variation in crown expansion traits, including twig intensity (number of twigs per first-order branch), branch intensity (number of branches per individual) and crown volume. In addition, tree diversity had divergent effects on leaf arrangement traits, with greater variation in leaf intensity (number of leaves per twig) and petiole diameter, but reduced variation in twig angle and petiole length among interacting individuals. Greater variations in crown volume, branch intensity, leaf intensity and twig intensity therefore promoted both crown complementarity and canopy packing. Our findings suggest that variations in crown architectural traits play crucial roles in mediating the positive effects of tree diversity on tree crown complementarity and canopy packing. Our study highlights that diversity-driven variation in crown architectural traits provides a key mechanistic pathway linking tree diversity to canopy processes in early-stage experimental forests, with important implications for ecosystem structure and productivity.

Journal Article

Interspecific competition promotes root foraging of a clonal plant via physiological integration
Fang-Ru Wu, Jun-Nan Liu, Lin-Xuan He, Ning-Fei Lei, Jin-Song Chen, Fei-Hai Yu
2026, 19 (4): rtag026.
doi:10.1093/jpe/rtag026
Abstract ( 91 )   PDF（pc） (1464KB) ( 7 )   Save
Root foraging is a common response of plants to heterogeneous soils. Individuals (ramets) of clonal plants are often connected, allowing resource and signal sharing, and thus cooperative responses to environmental heterogeneity. However, it remains unknown how intraspecific and interspecific competition on a ramet influences root foraging of its connected ramet in heterogeneous soils. We grew a younger ramet of the stoloniferous herb Fragaria pentaphylla either in a heterogeneous environment consisting of high- and low-nutrient soil patches or a homogeneous environment containing an even mixture of the two soils, and its connected older ramet in a homogeneous, high-nutrient soil. The older ramet grew alone or with a ramet of the same or a different species (Duchesnea indica, Hydrocotyle sibthorpioides, or Centella asiatica). Regardless of competition, the younger ramet of F. pentaphylla exhibited root foraging in the heterogeneous soil, with a stronger response when its older ramet grew with C. asiatica than when it grew alone. However, growing with other species did not influence root foraging. Root, shoot, and total mass of the younger ramet and the whole clone of F. pentaphylla were higher in the heterogeneous than in the homogeneous soil when the older ramet grew with D. indica or H. sibthorpioides, but such effects disappeared when it grew alone, or with F. pentaphylla or C. asiatica. Our findings suggest that interspecific competition can promote root foraging of clonal plants in heterogeneous soils, but such an effect is context-dependent and not necessarily associated with performance promotion.

Functional traits explain the enhancement of denitrification by wetland plants
Yingji Pan, Lars Lønsmann Iversen, Peter M van Bodegom
2026, 19 (4): rtag023.
doi:10.1093/jpe/rtag023
Abstract ( 64 )   PDF（pc） (1044KB) ( 10 )   Save
Denitrification is one of the most important ecosystem functions in wetland ecosystems, affecting nutrient cycling, water purification and the global nitrogen budget. However, the effects of wetland plants on denitrification remain unclear because of the complex plant-microbe-substrate interactions involved. In this study, we evaluated the effects of 25 wetland plant species traits on denitrification based on data from meta-analyses on denitrification, global wetland plant trait databases and structural equation modelling. We used plant functional traits as an indicator to quantitatively model the multifaceted ecological processes controlling denitrification as well as the overall denitrification enhancement by wetland plants. Our results revealed that both direct and indirect (i.e. the effect of one variable on another is mediated by a third variable) pathways strongly contribute to the overall enhancement of denitrification by wetland plants. Specifically, wetland plant root traits jointly controlled substrate oxygen availability, which reduced the enhancement of denitrification by wetland plants through oxygen inhibition effects. Plant nitrogen status facilitated denitrification enhancement probably through organic nitrogen input by plant leaves and root exudates. Root biomass directly decreased denitrification enhancement through competition for nitrogen uptake with denitrifying bacteria. Our results provide a systematic view of the effect of wetland plant traits on denitrification enhancement. The application of plant functional traits in revealing the complex denitrification processes helps us to better understand the impacts of plants on wetland ecosystem functioning and inspire new practices in ecological engineering and ecological management on denitrification through a trait-based perspective.

Reviews

Plant functional traits: a key to understanding and restoring ecosystem structure and functioning in wetlands
Hao Liu, Lijuan Cui, Wei Li, Guangxuan Han, Jihua Wu, Bo Li, Ming Nie
2026, 19 (4): rtag125.
doi:10.1093/jpe/rtag125
Abstract ( 129 )   PDF（pc） (1455KB) ( 68 )   Save
Plant functional traits offer a mechanistic framework for understanding how plant communities respond to environmental change and shape ecosystem functioning. However, despite rapid advances over the past decades, the role of functional traits in driving wetland ecosystem functioning remains less well understood than in terrestrial systems, thereby limiting effective wetland conservation and restoration. In this review, we synthesize existing evidence on how plant functional traits and functional diversity influence key wetland ecosystem functioning, such as productivity, carbon cycling and nutrient cycling. We find that functional traits are key regulators of ecosystem functioning; therefore, targeted restoration should prioritize species with specific traits. We also call for coordinated actions across local and landscape scales to manage potential trade-offs among restoration objectives and enhance ecosystem multifunctionality. Clarifying the roles of functional diversity and wetland-specific flooding-adaptive traits in driving ecosystem functioning is identified as an important focus for future work. Moreover, a deeper understanding of how functional traits and diversity regulate wetland ecosystem functioning requires more manipulative experiments. This review highlights the role of plant traits in mechanistically linking vegetation dynamics to ecosystem functioning in wetlands.

Data-model integration in global change manipulative experiments: progresses, challenges and future directions
He Lyu, Xue-Qian Zhang, Jian Su, Ming-Kai Jiang
2026, 19 (4): rtag033.
doi:10.1093/jpe/rtag033
Abstract ( 135 )   PDF（pc） (2089KB) ( 44 )   Save
Anthropogenic global change profoundly affects terrestrial ecosystem structure and function, creating an urgent and persistent need to accurately predict future ecosystem states. Field-based manipulative experiments provide critical mechanistic insights into these impacts but are inherently limited in spatio-temporal scope. Conversely, process-based models can extrapolate to broader scales but often contain simplified or unrealistic mechanisms that lead to uncertain projections. Data-model integration has emerged as an essential approach to bridging this gap, testing model assumptions against empirical evidence and guiding experimental design via model-based hypotheses. This review synthesized progress in integrating manipulative experiments with process-based models across three key global change drivers: elevated CO₂, climate change (warming and altered rainfall) and nutrient manipulation. We demonstrated how this integration reduced key uncertainties in processes such as photosynthesis, carbon-nutrient coupling and soil biogeochemistry, whilst exposing persistent gaps in plant hydraulics, microbial dynamics and multifactorial stresses. These advances were most pronounced in representing CO₂ fertilization effects, including improved stomatal optimization theory, dynamic carbon allocation schemes and coupled carbon-nitrogen-phosphorus cycling. By contrast, its application to warming, rainfall change and multi-nutrient interactions remained underdeveloped. To catalyze future progress, we propose specific strategies to foster a more synergistic cycle of knowledge co-production. These include prioritizing the quantification of mechanism-specific data to develop dynamic model formulations, systematically using multi-site experimental networks to benchmark and refine model processes across scales, and strategically employing models to design targeted experiments. Ultimately, these strategies are indispensable for developing more realistic models and achieving predictive understanding of ecosystem responses to global change.

Simulated livestock defoliation enhances plant diversity and productivity in China’s grasslands: a meta-analysis
Yu Liu, Yanli Feng, Xiang-Sheng Wang, Hongbiao Zi
2026, 19 (4): rtaf231.
doi:10.1093/jpe/rtaf231
Abstract ( 311 )   PDF（pc） (2215KB) ( 83 )   Save
Livestock grazing can alter plant productivity and diversity through defoliation, trampling and excretion. To isolate effects of defoliation, researchers commonly employ clipping experiments, although these effects of defoliation can vary considerably depending on the intensity and duration of grazing, as well as the type of ecosystem. Here, we compiled data from 1006 pairs of observations across 96 studies to assess the impacts of simulated livestock defoliation on various measures of plant diversity (including evenness) and productivity in China’s grasslands. Overall, simulated livestock defoliation resulted in greater species richness and evenness, along with elevated aboveground net primary productivity (ANPP) and belowground biomass (BGB), but lower aboveground biomass (AGB). Moderate levels of defoliation produced a stronger positive response in diversity compared to light or heavy defoliation, similar to later-season defoliation. Such effects were absent in alpine meadows, which leading to a negative association between responses of diversity and elevation. AGB was reduced by defoliation in all contexts, while BGB increased more when defoliation was light, later in the season and with shorter experimental durations; these effects were stronger in drier areas. Simulated grazing’s effects on ANPP switched from positive to negative as intensity increased. Changes in diversity were positively correlated with changes in ANPP in response to defoliation. These findings highlight that the effects of defoliation are context-specific in China’s grasslands, with important implications for grassland management and conservation.

Individual and interactive effects of nitrogen addition and drought on carbon uptake and allocation in terrestrial plants
Chengqian Pan, Junhong Shu, Zhen Zhang, Qinning Jiang, Liehua Tie, Jie Wang, Honglang Duan, Shengnan Ouyang
2026, 19 (4): rtaf228.
doi:10.1093/jpe/rtaf228
Abstract ( 185 )   PDF（pc） (1656KB) ( 56 )   Save
The increasing frequency of drought events and elevated nitrogen (N) deposition both affect plant carbon (C) utilization, but whether their individual and interactive effects promote, inhibit or have no effect on C uptake and allocation remains unclear. We conducted a meta-analysis using 1247 observations from 84 published articles to assess how N addition and drought jointly affected plant photosynthesis, biomass allocation and nonstructural carbohydrates (NSC) allocation. Our results showed that N addition overall increased plant net photosynthetic rate (Pn) and biomass accumulation but decreased whole plant total NSC storage. Conversely, drought overall decreased Pn and biomass accumulation while increased whole plant total NSC storage. N addition significantly increased aboveground biomass allocation, whereas drought significantly reduced leaf biomass (LB). Although N addition and drought did not have significant interaction on Pn, biomass allocation and NSC allocation in terrestrial plants, their interaction significantly increased the root biomass of evergreen broadleaf plants, the LB of deciduous broadleaf plants and the root-to-shoot ratio of annual herbs. In conclusion, N addition and drought had opposite effects on C uptake, biomass accumulation and NSC storage in terrestrial plants. The interaction of N addition and drought on biomass allocation was affected by plant functional types. This study enhances our understanding of plant C utilization strategies under multiple environmental changes.

Research Articles

Differential responses of stomatal and leaf anatomical traits explain wheat cultivar sensitivity to ozone
Yanze Ma, Rong Cao, Evgenios Agathokleous, Yansen Xu, Longxin He, Zhaozhong Feng
2026, 19 (4): rtag083.
doi:10.1093/jpe/rtag083
Abstract ( 67 )   PDF（pc） (2193KB) ( 20 )   Save
Tropospheric ozone (O₃) is a major air pollutant that threatens wheat production. However, the mechanisms underlying cultivar-specific responses remain unclear, particularly how stomatal traits and leaf structural characteristics contribute to differences in O₃ sensitivity among cultivars. A field experiment was conducted using 13 winter wheat (Triticum aestivum L.) cultivars exposed to ambient (A-O₃) or elevated (E-O₃, 1.5 times A-O₃) O₃ treatment in a Free-Air O₃-Concentration Enrichment system (O₃-FACE). Elevated O₃ significantly increased stomatal density on both adaxial and abaxial leaf surfaces, with a stronger response on the adaxial side, indicating independent regulation between surfaces. At the anthesis stage, stomatal and pore width significantly increased under E-O₃, whereas their length was not affected. Elevated O₃ significantly reduced adaxial epidermal thickness, abaxial epidermal thickness, mesophyll tissue thickness, and total leaf thickness during grain filling, with significant O₃ × cultivar interactions for all traits except abaxial epidermal thickness. Cultivars were classified into sensitive, intermediate, and tolerant groups. Sensitive cultivars exhibited significant reductions in leaf structure, whereas tolerant cultivars largely maintained or even enhanced structural integrity. Overall, cultivar sensitivity to O₃ was not directly associated with stomatal traits but rather with the ability to preserve leaf anatomy. These findings suggest that maintaining flag leaf structure is critical for improving wheat resilience to rising O₃ levels.

Long-term warming and nitrogen addition drive interface-specific bacterial assembly and enhance soil-leaf microbial connectivity
Yi Zhu, Yunzhuo Wen, Lu Bai, Guodong Han, Jinglei Tang, Zijian Ye, Zhiqiang Qu, Guijie Zhang, Haiyan Ren
2026, 19 (4): rtag088.
doi:10.1093/jpe/rtag088
Abstract ( 101 )   PDF（pc） (1398KB) ( 21 )   Save
Plant-microbe interactions are strongly influenced by global environmental change, but bacterial responses in diversity, assembly and cross-interface connectivity across multiple plant-soil interfaces remain poorly understood. Here, we investigated bacterial communitiated interface-specific responses in bacterial community structure, assembly processes and the contributions of different interfaces to leaf endophytic bacterial communities. We found that interface identity plays the dominant role in shaping bacterial phylogenetic α- and β-diversity, with soil communities exhibiting higher diversity than phyllosphere communities. Nitrogen addition significantly reduced phylogenetic α-diversity and resulted in a more stochastic phylogenetic structure in bulk soil, whereas warming enhanced phylogenetic clustering in rhizosphere soil. Notably, warming increased phylogenetic dispersion and β- diversity of leaf epiphytic bacteria but decreased β-diversity in rhizosphere soil, indicating contrasting above- and belowground responses. Community assembly across interfaces was dominated by homogeneous selection, with stochastic processes contributing in an interface-dependent manner. Leaf endophytic communities remained remarkably stable, suggesting strong host filtering. Microbial source tracking revealed that warming and N addition increased soil-derived contributions to leaf endophytes, with over 70% of the community originating from soil under global change treatments. Overall, our results demonstrate that long-term warming and N addition drive interface-specific bacterial assembly and enhance soil to leaf microbial connectivity, highlighting the importance of a multi-interface perspective in understanding microbial responses to global change.

Multifunctional group species reseeding reduces community-level root exudate rate at severely degraded alpine meadows
Wenying Wang, Yuanming Xiao, Guoying Zhou, Xiaoyun Wang, Bo Fan, Jiaxin Xu
2026, 19 (4): rtaf198.
doi:10.1093/jpe/rtaf198
Abstract ( 176 )   PDF（pc） (1657KB) ( 17 )   Save
Root exudates play a crucial role in the communication and interaction between plants and soil. However, the responses of carbon (C), nitrogen (N) and phosphorus (P) exudation rates and their stoichiometric ratios to multifunctional group species reseeding in severely degraded alpine meadows remain poorly understood. This study was conducted in a severely degraded alpine meadow and four species composition treatments were established: grass mixtures, grass + legume mixtures, grass + legume + sedge mixtures and grass + legume + forb mixtures. The results showed that among the four reseeding treatments, the grass + legume + sedge mixture exhibited the lowest root C exudate rate and total exudate capacity, while N and P exudation rates, as well as their total exudate capacities, did not differ significantly between treatments. The carbon-to-phosphorus (C:P) ratio of root exudate was lowest in the grass + legume + sedge mixture, while the carbon-to-nitrogen (C:N) and nitrogen-to-phosphorus (N:P) ratios showed no significant differences among the four reseeding treatments. Root C and P exudation rates, as well as the C:N and N:P ratios, were significantly correlated with plant diversity, aboveground biomass, total biomass, soil organic matter and electrical conductivity. Variation partitioning analysis showed that root C exudate rate was most strongly influenced by biomass, whereas N and P exudate rates were more strongly affected by plant diversity. These findings suggest that species reseeding patterns significantly influence root exudates and their stoichiometric characteristics and contribute to understand the trajectories of soil microbes and soil health under reseeding.

The leaf economics spectrum drives soil nitrification in subtropical forests
Xiuzhen Shi, Yaqi Shao, Zhijie Yang, Francis Q. Brearley, Manuel Esteban Lucas-Borja, Ding Feng, Yajun Shao, Jianqing Wang
2026, 19 (4): rtag003.
doi:10.1093/jpe/rtag003
Abstract ( 99 )   PDF（pc） (893KB) ( 13 )   Save
Nitrification is a crucial biogeochemical process that regulates soil inorganic nitrogen forms and triggers soil nitrogen losses. While the prevailing paradigm focuses on the role of functional microbial guilds that drive soil nitrification, a clear mechanistic link between tree species and soil nitrification remains to be established in forest ecosystems. With a common garden experiment, we examined the impacts of the leaf economics spectrum, tree phenology, and symbiotic fungal associations on soil nitrification across 12 subtropical tree species in January and September. Our results revealed that soil potential nitrification rates, ranging from -2.13 to 1.96 mg N kg^-1 d^-1, varied among different tree species. Liquidambar formosana exhibited the highest soil nitrification rate, while Lindera communis and Elaeocarpus decipiens had the lowest soil nitrification rates at both sampling times. Leaf traits were stronger predictors of soil nitrification than soil variables. In particular, acquisitive tree species characterized by greater specific leaf area and lower leaf dry matter content significantly promoted soil nitrification. Deciduous tree species exhibited significantly higher soil potential nitrification rates than those of evergreen tree species. Structural equation models showed that the leaf economics spectrum positively affected litter N content, which in turn increased soil ammonium availability and subsequently promoted ammonia-oxidizing archaeal abundance, ultimately facilitating soil nitrification. Taken together, our study demonstrates a leaf trait-based framework for linking tree species to ecological processes and emphasizes that the choice of tree species based on the leaf economics spectrum plays a vital role in predicting ecosystem functioning.

Microbial carbon use efficiency governs the accumulation of microbial-derived carbon in restored mangroves
Xingyun Huang, Fangyuan Guan, Zhe Lu, Guoming Qin, Yongxing Cui, Tao Li, Evans Asenso, Ruichang Shen, Benjamin J. Wainwright, Jingwei Shi, Lulu Zhang, Hui Li, Jingfan Zhang, Jinge Zhou, Ruyi Ding, Hua He, Faming Wang
2026, 19 (4): rtaf230.
doi:10.1093/jpe/rtaf230
Abstract ( 209 )   PDF（pc） (1625KB) ( 41 )   Save
While mangrove restoration has a great potential for enhancing soil organic carbon (SOC) sequestration in coastal wetlands, microbial-mediated SOC decomposition introduces huge uncertainty to this process. Microbial carbon use efficiency (CUE) is a crucial trait for microorganisms controlling SOC turnover, but how mangrove restoration could affect microbial CUE remains unclear. Here, we investigated the effects of mangrove restoration on microbial CUE in a typical restored mangrove wetland and further explored its connection to microbial necromass carbon (MNC) content. Our results revealed mangrove restoration increased microbial CUE by 37.84%–56.76% due to an increase in organic carbon quality and a shift in microbial community structure from fast-growing r-strategist (bacteria-dominated including Proteobacteria and Bacteroidota) to slow-growing K-strategist (fungal taxa and bacterial phyla such as Actinobacteriota, Acidobacteriota, and Chloroflexi). Microbial CUE was also positively correlated with MNC, explaining 73% and 69% variations in fungal and bacterial necromass C, respectively. These findings indicate that mangrove restoration enhances SOC sequestration not only through increased plant-derived carbon input but also by elevating microbial CUE and promoting MNC accumulation. Although bacterial necromass carbon showed a higher percentage increase, fungal necromass constituted the dominant portion of the accrued microbial-derived carbon pool, underscoring the critical role of fungal communities in the formation of stable SOC. Our study highlights the significant role of microbial processes in promoting SOC accumulation during mangrove restoration. These results emphasize the importance of incorporating microbial processes into coastal wetland restoration strategies to maximize C sequestration.

Soil conditions mediate cucumber-root (Medeola virginiana) plant responses to white-tailed deer herbivory
Danielle Begley-Miller, Duane R. Diefenbach, Marc E. McDill, Patrick J. Drohan, Autumn E. Sabo, Justin Zweck, Christopher S. Rosenberry, Bret D. Wallingford, Emily J. Domoto
2026, 19 (4): rtaf225.
doi:10.1093/jpe/rtaf225
Abstract ( 81 )   PDF（pc） (1477KB) ( 5 )   Save
In eastern North America, cucumber-root (Medeola virginiana) is a widely distributed perennial forest herb that has been used as an ecological indicator of white-tailed deer (Odocoileus virginiana) browsing due to its predictable responses to deer exclusion (i.e. increased height, abundance). However, cucumber-root is less likely to occupy sites with high concentrations of soil manganese (Mn), which may limit its utility as an indicator under limiting soil conditions. We examined responses of cucumber-root total counts and flowering abundance to deer exclusion, competitive release from surrounding vegetation, and soil application of dolomitic limestone to determine the relative effects of these treatments over 7 years (2014–2021). Prior to treatment, initial total and flowering abundance were best explained by soil extractable Mn concentration. Post-treatment, fencing best explained increases in total counts, but flowering abundance was most affected by soil extractable Mn and pH. Initial soil Mn concentrations determined the effectiveness of dolomitic limestone application; microplots with moderate to high soil Mn (>6 cmol_c kg^-1) had increased flowering with increased pH, while flowering decreased on microplots with initially low soil Mn concentrations (<6 cmol_c kg^-1). We suspect changes to soil chemistry from liming affected plant stress, but that stress was either alleviated or intensified depending on initial soil Mn concentrations. Herbivory is an important driver of plant abundance across our study area but flowering response, a critical component of plant demography, seems to be driven by soil Mn. Cucumber-root may have limited utility as an indicator because soil chemistry mediates flowering responses to deer exclusion.

Global patterns and drivers of drought resilience across latitudes and forest taxa
Ye Zhang, Yixue Hong, Xibin Sun, Weina Jia, Hao Chen
2026, 19 (4): rtaf223.
doi:10.1093/jpe/rtaf223
Abstract ( 182 )   PDF（pc） (1315KB) ( 72 )   Save
Extreme drought events are projected to increase in frequency and severity, posing serious threats to the stability of forest ecosystems. Forest drought resilience—an essential indicator of ecosystem stability and carbon sequestration potential under climate change—remains poorly understood in terms of its spatial distribution and variation across plant functional types. Here, we assessed global patterns and underlying drivers of forest drought resilience across latitudinal gradients, plant functional types (angiosperms vs. gymnosperms), and taxonomic ranks, using generalized linear models that integrate 282 tree-ring chronologies with satellite environmental and biotic data. Results showed that high-latitude forests had significantly lower drought resilience than those in mid- and low-latitude regions, primarily due to the combined constraints of limited water availability and low temperature. Angiosperm-dominated forests exhibited higher drought resilience than gymnosperm-dominated forests, with the former mainly driven by nutrients and heat, but the latter more constrained by water availability and species diversity. Forest drought resilience also differed among specific taxonomic ranks. Notably, the angiosperm genus Quercus exhibited high drought resilience, while some gymnosperm genera, such as Tsuga and Juniperus, also demonstrated strong drought tolerance through distinct physiological and morphological adaptations. These findings reveal that forest drought resilience is jointly shaped by climatic constraints and biotic traits, with clear latitudinal and phylogenetic differences. Recognizing these patterns can inform region-specific forest management and conservation strategies aimed at enhancing ecosystem stability under intensifying climate change.

Effects of water-nitrogen interaction on resource use efficiency and adaptive strategies in the key growth period of Carex schmidtii
Qiu-Ying Ma, Li Wu, Hai-Bo Jiang, Tao Yang, Hong-Feng Bian, Hai-Tao Wu, Chun-Guang He
2026, 19 (4): rtag006.
doi:10.1093/jpe/rtag006
Abstract ( 92 )   PDF（pc） (1416KB) ( 9 )   Save
Climate change and intensified agricultural activities are altering hydrological regimes and nitrogen inputs in wetland ecosystems, yet the mechanisms by which dominant wetland plants coordinate their responses to water-nitrogen interactions across growth stages remain insufficiently understood. This study investigated the dominant species, Carex schmidtii, utilizing a controlled experiment with three water levels (low water level, LW; control water level, W0; high water level, HW) and three nitrogen additions levels (no nitrogen addition, N0; low nitrogen addition, N1; high nitrogen addition, N2). Results revealed that C. schmidtii displayed pronounced stage-dependent plasticity to water-nitrogen interactions. Water availability emerged as the key factor determining growth and resource allocation, whereas nitrogen effects were strongly modulated by water conditions. During the vegetative growth stage, water limitation suppressed plant growth regardless of nitrogen addition, Under no nitrogen addition, plant height in the low water level treatment decreased by 22.16% relative to the control water level, and this growth inhibition persisted even under high nitrogen inputs, indicating that nitrogen could not compensate for water deficiency. At low water level, water use efficiency (WUE) and nitrogen use efficiency (NUE) reached the highest values and displayed a positive correlation, indicating efficient resource utilization. During the reproductive growth stage, nitrogen played a stronger role in promoting structural development and maintaining functional stability. Nitrogen additions alleviated NUE reduction under low water, whereas high water induced an escape response marked by reduced WUE (−29.10%) and elevated NUE (+119%). These findings highlight contrasting coordination strategies across growth stages and provide new insight into the adaptive mechanisms of dominant wetland plants under shifting hydrological and nutrient regimes.

Cloud cover, tree size and species modulate the positive effects of aerosols on tree growth
Bin Wang, Zhou Jia, Zhenhua Wang, Chengzhang Wang, Mingkai Jiang, Lingli Liu, Xin Wang
2026, 19 (4): rtag015.
doi:10.1093/jpe/rtag015
Abstract ( 73 )   PDF（pc） (2402KB) ( 12 )   Save
Atmospheric aerosols can influence plant growth and terrestrial carbon cycling by altering solar radiation regimes and microclimate conditions. However, accurately quantifying their net effects requires a better understanding of how aerosol-growth relationships are modulated by cloud cover conditions and plant traits, for which empirical evidence remains limited. To address this, we conducted a six-year field campaign to monitor PM_2.5 concentrations (as a proxy for aerosol loading), meteorological variables, and daily stem growth in two temperate tree species: aspen (Populus euramericana Neva.) and pine (Pinus tabuliformis Carr.). We systematically evaluated how aerosols affect tree growth and how these effects are regulated by cloud cover, tree size, and species. Our findings revealed that aerosols generally promoted the stem growth of aspen, primarily through their diffuse radiation fertilization effect and concomitant improvements in air humidity (i.e. lower vapor pressure deficit). This positive effect was highly dependent on sky conditions: growth increased linearly under clear skies but exhibited a saturating-to-declining trend under overcast skies. Additionally, tree size influenced aspen’s growth response to aerosols, with smaller trees showing a lower absolute enhancement in stem cross-sectional area but a greater relative stem growth rate under high aerosol conditions. In contrast to the fast-growing aspen, the slow-growing pine showed no significant stem growth response to aerosols. These field-based findings propose a mechanistic framework for studying aerosolecosystem interactions and provide empirical benchmarks essential for improving predictions of plant growth under realistic environmental conditions.

Drought-induced reductions in plant residue decomposition across organs consistently differ between two tree species (gymnosperm and angiosperm) in drylands
Qianqian Zuo, Guopeng Liang, Zebin Jiao, Lulu Ma, Xiangyu Ji, Xian He, Zhiyuan Xu, Zhenhong Hu
2026, 19 (4): rtag019.
doi:10.1093/jpe/rtag019
Abstract ( 70 )   PDF（pc） (1779KB) ( 12 )   Save
Drought strongly influences plant residue decomposition and forest carbon cycling, and these effects are mediated by tree species traits. Although angiosperm residues generally decompose faster than gymnosperm residues due to higher nutrient concentrations, it remains unclear whether drought effects differ consistently between tree species across different plant organs and how underlying traits drive these differences. Herein, we examined the decomposition of wood, fine roots and leaf litter from Pinus tabuliformis (gymnosperm) and Robinia pseudoacacia (angiosperm) under 0%, 40%, and 80% rainfall reduction on the Loess Plateau, China. Drought significantly decreased plant residue decomposition, with the magnitude of reduction varying with both drought intensity and tree species. Decomposition of all plant residues declined more under 80% rainfall reduction than under 40% rainfall reduction. Moreover, under 80% rainfall reduction, decomposition declined significantly more in R. pseudoacacia than in P. tabuliformis, whereas no significant difference was observed under 40% rainfall reduction. This is because R. pseudoacacia has lower carbon and lignin concentrations, lower Proteobacteria abundance, and higher phosphorus concentration and Actinobacteriota abundance, yielding greater moisture sensitivity of its residue decomposition. Furthermore, drought-induced reductions in decomposition were greater for wood and leaf litter than for fine roots. Variation partitioning analysis and structural equation modeling further demonstrated that interactions among residue moisture, traits, and microbes governed jointly decomposition. Our findings highlight that contrasting tree species traits underlie drought-induced reductions in residue decomposition in drylands, which have important implications for predicting dryland carbon fluxes under future climate change characterized by increasing drought intensity and forest mortality.

Short-term intercropping reduces total symbiotic N₂ fixation and alters the fate of nitrogen derived from free-living fixation
Runfu Li, Wenli Ding, Shikui Dong, Lina Qi, Hongqiang Li, Wen-Feng Cong, Fusuo Zhang, Hans Lambers
2026, 19 (4): rtag020.
doi:10.1093/jpe/rtag020
Abstract ( 112 )   PDF（pc） (1380KB) ( 13 )   Save
Symbiotic (SNF) and free-living (FLN) N₂ fixation are key bioavailable nitrogen (N) sources in agroecosystems; yet, their integrated response to intercropping remains inadequately understood. We conducted a field experiment with intercropped silage maize (Zea mays L.) and Chinese milk vetch (Astragalus sinicus L.), assessing the intercropping effects on N dynamics by examining SNF and FLN in conjunction with soil properties and the composition of rhizosphere microbial communities, thereby linking plant performance with belowground processes. Intercropping increased silage maize total dry matter yield by 14.36% but reduced the total amount of symbiotically fixed N (Ndfa). This reduction was due to the suppressed biomass and lower tissue N concentration of the intercropped Chinese milk vetch, while its fixation efficiency (%Ndfa) remained stable. Crucially, while the gross rate of soil FLN was unaltered, intercropping reprogrammed the partitioning of FLN-derived ¹⁵N in a species-specific manner: allocation to the microbial biomass N pool increased in the Chinese milk vetch rhizosphere (from 13.85% to 25.37%), whereas allocation to the plant-available nitrate (NO₃^–-N) pool increased in the silage maize rhizosphere (from 2.67% to 15.67%). Several dominant genera of diazotrophs (Sinorhizobium, Bradyrhizobium), other bacteria (Microvirga, Bacillus), and fungi (e.g. Fungi gen Incertae sedis) were positively correlated with the proportion of inorganic N derived from FLN. We conclude that short-term intercropping reduces total symbiotic N input but enhances system performance by species-specifically redirecting FLN-derived N, a process mediated by crop-specific rhizosphere microbiomes to optimize N bioavailability for the cereal crop.

Mycorrhizal strategy mediates anthropogenic impacts on plant range filling in China
Yujun Yao, Xian Zhou, Junfeng Gao, Haoyuan Han, Yue Zhang, Keping Ma, Wubing Xu, Lei Chen
2026, 19 (4): rtag005.
doi:10.1093/jpe/rtag005
Abstract ( 80 )   PDF（pc） (1173KB) ( 14 )   Save
Mycorrhizal symbioses are critical for plant population and community dynamics, yet their role in mediating plant geographic spread under increasing anthropogenic pressure remains poorly understood. Here, we compiled geographic distribution and mycorrhizal information for 8791 vascular plant species across China and investigated how plant mycorrhizal strategies interact with human footprint to shape the extent to which species fill their potential ranges across species and space. We found that anthropogenic activities significantly affected range filling of arbuscular mycorrhizal plants, disproportionately reducing range filling of narrowranged species while benefiting widespread species. Conversely, range filling of ectomycorrhizal plants was primarily associated with abiotic environments. Our results suggest that mycorrhizal symbioses play a critical role in mediating plant responses to anthropogenic pressures across broad geographic scales and highlight the need to integrate plant-mycorrhizal interactions to predict biodiversity shifts in a changing environment.

Climate and human activities mediate the trade-off of plant above- and below-ground C, N and P stocks in typical steppes along the precipitation gradient
Yi Zhou, Shenghua Chang, Xiaojuan Huang, Wenjun Wang, Fujiang Hou, Yanrong Wang, Zhibiao Nan
2026, 19 (4): rtaf227.
doi:10.1093/jpe/rtaf227
Abstract ( 91 )   PDF（pc） (1890KB) ( 9 )   Save
Ongoing human activities and climate change threaten global grasslands, where plant nutrients are essential for ecosystem stability. However, long-term assessments (1985–2022) of above- and below-ground nutrient tradeoffs remain limited. Here, we conducted a 37-year study along the precipitation gradient (267–441 mm) to investigate the dynamics and trade-offs of plant carbon (C), nitrogen (N) and phosphorus (P). Our study found that with increasing local precipitation, above-ground C, N and P contents increased, while below-ground C content declined. The long-term response of plant nutrients varied spatially; the drier north (267 mm) and central region (334 mm) showed increased above-ground C but decreased N and P over time, whereas the opposite pattern occurred in the wetter south (441 mm). Additionally, the trade-off values of plant C, N and P stocks increased with local precipitation, and temporal stability of the N and P trade-off values was lowest in the drier north. Finally, precipitation fluctuation, fertilizer input and per capita GDP were identified as the key drivers of plant above- and below-ground nutrient dynamics in the northern, central and southern regions, respectively. With increasing local precipitation, the effect of climate on trade-off values shifts from negative to positive, whereas the effect of human activities shifts from positive to negative. Our findings highlight that the long-term response of plant nutrients is regulated by local precipitation patterns, through which the precipitation gradient has reshaped plant nutrient regulation by shifting the dominant driver from climatic to human activities factors.

Forest structure determines the structure and functional traits of liana community during secondary succession in a temperate oak forest
Zhe Zhou, Binzhou Chen, Yani Yuan, Xu Ai, Yongfu Chai, Ming Yue and Yaoxin Guo
2026, 19 (4): rtag013.
doi:10.1093/jpe/rtag013
Abstract ( 84 )   PDF（pc） (1529KB) ( 13 )   Save
Forest disturbance and climate change have caused a growing abundance of lianas in tropical and many temperate forests, which imparts a sense of urgency to explore the factors that control liana community assembly. Here, we examined the changes in liana community structure and functional traits during secondary succession in a warm temperate oak forest, and then analyzed how these varied with forest structural and soil properties. Liana species showed lower stem density in the late stage (85 ind. ha^-1) than the earlier two stages (190 ind. ha^-1 and 230 ind. ha^-1, respectively). Liana diversity also decreased along the succession. Compared with the earlier successional stages, lianas in the late successional stage invested more in acquisitive stem (lower wood density) and root (lower root carbon content). The decreases in liana abundance and wood density were strongly related to the decreasing tree diversity and the increasing canopy cover, tree diameter and tree height, with weak relationships with soil properties. These results demonstrate that forest structure is the main driver of liana community structural and functional assembly during forest succession, and is likely to shape liana community mainly by filtering stem traits.

Research Article

Predicting the spatial distribution of vegetation alliances with ecological knowledge under sample-limited conditions
Fang-He Zhao, Ningxia Jia, Ke Guo, A-Xing Zhu, Cheng-Zhi Qin
2026, 19 (4): rtag001.
doi:10.1093/jpe/rtag001
Abstract ( 107 )   PDF（pc） (4227KB) ( 15 )   Save
Accurate spatial distribution of vegetation types is fundamental to understanding ecosystem structure, biodiversity patterns and environmental responses. However, predicting the distribution of lower-level vegetation classification units such as alliances remains challenging due to limited and uneven sample availability, particularly for rare or narrow-niche communities. To address this issue, this study proposed the KnowSim method that integrates expert-defined ecological knowledge to evaluate environmental similarity between locations. Vegetation types were predicted by assigning each site the type of its most ecologically similar sample. The method was tested in two regions of the Tibetan Plateau (Bome and Zoige), which exhibit contrasting yet complementary climatic and topographic conditions, together representing the Plateau’s typical environmental settings. Results demonstrate that KnowSim consistently outperformed statistical methods (Random Forest, eXtreme Gradient Boosting, Support Vector Machine and Logistic Regression) in both accuracy and type diversity. The improvement was particularly evident for alliances with sparse samples, achieving up to 24.6% higher accuracy in Zoige for alliances with fewer than five training samples. Moreover, the predicted vegetation maps better aligned with ecological gradients and field observations, demonstrating both ecological interpretability and predictive robustness under sample-limited conditions.

Rainfall and mycorrhizal association jointly influence conspecific negative density dependence in a tropical forest
Haikun Liu, Hang Shi, Quan Zhou, Man Hu, Liang Chen, Daoliang Shi, Haishan Dang, Quanfa Zhang
2026, 19 (4): rtag014.
doi:10.1093/jpe/rtag014
Abstract ( 64 )   PDF（pc） (951KB) ( 1 )   Save
Understanding how biotic interactions vary across environmental gradients is critical for explaining the patterns of species coexistence in forest communities. Recent studies indicate that mycorrhizal association and environmental factors, particularly rainfall, can shape variations in conspecific negative density dependence (CNDD), although long-term community level evidence from natural forests remains limited. Using 20-year seedling censuses from a species-rich tropical forest, we investigated how interannual rainfall variability and mycorrhizal type modulated CNDD and seedling survival. Our results showed that seedling survival was greater in the years with higher rainfall, which was largely regulated by the interactions between the conspecific and heterospecific neighbors. Notably, rainfall and conspecific density were the predominant drivers of seedling survival, showing that seedlings exhibited higher survival at low conspecific densities and positive or nonlinear responses to rainfall. Heterospecific neighbors also had positive effects on seedling survival, which may be influenced by habitat conditions. Moreover, CNDD was stronger in arbuscular mycorrhizal (AM) species than in ectomycorrhizal (ECM) species, particularly in wetter years. Our findings revealed that interannual rainfall interacted with species’ mycorrhizal strategies to shape demographic outcomes, underscoring the pivotal role of mycorrhizal types in determining seedling dynamics. Thus, our study highlights the importance of incorporating mycorrhizal types into the predictions of tropical forest biodiversity.

Research Articles

Arbuscular mycorrhizal fungi dictate plant responses to water availability
Hannah Locke, Kerri M. Crawford
2026, 19 (4): rtag017.
doi:10.1093/jpe/rtag017
Abstract ( 54 )   PDF（pc） (732KB) ( 3 )   Save
Arbuscular mycorrhizal (AM) fungi are well documented to alleviate physiological stress in plants. While AM fungal benefits under low-water conditions are well studied, AM fungal benefits under high-water conditions are far less understood. Previously, direct experimentation on AM fungal effects on plant performance has largely focused on agricultural crop species, frequently using categorical ambient and drought condition treatments rather than leveraging gradients appropriate for detecting non-linear responses. Thus, there is little understanding about how AM fungi may mediate native, terrestrial plant responses across gradients of water availability. Here, we tested the effects of AM fungi on a common, ruderal plants species (Solidago altissima) across a wide range of water availability in a greenhouse experiment. AM fungi improved plant performance at moderate and high levels of water availability, but surprisingly AM fungi did not improve plant performance in the lowest water availability treatment groups. Most importantly, without AM fungi, S. altissima was unable to take advantage of increasing water availability, indicating that even for a ruderal plant species, mycorrhizal associations may be a critical component to plastic responses in plant performance under climate-driven changes in water availability.

Latitudinal variation in clonal trait covariances underlies local adaptation of the invasive Spartina alterniflora at low latitudes in China
Xincong Chen, Jingyun Chen, Fujia Wu, Yihui Zhang
2026, 19 (4): rtag028.
doi:10.1093/jpe/rtag028
Abstract ( 95 )   PDF（pc） (1246KB) ( 8 )   Save
Genetically based trait covariances are critical for invasive plant adaptation. Clonal growth can facilitate local expansion; however, the evolutionary relationship between clonal timing and performance remains underexplored. Particularly, it is unclear how these traits covary to affect adaptation across latitudes. Here, we investigated variation and covariance in two clonal traits (the timing of the first ramet emergence and peak number of ramets within a growing season) of Spartina alterniflora, an aggressive coastal invader in China. We sampled eight populations spanning the entire latitudinal range of S. alterniflora along the Chinese coast (21° N–38° N). These seeds were cultivated in three common gardens at low (21° N), mid (28° N), and high (38° N) latitudes. Plants from low-latitude garden exhibited significantly earlier ramet emergence and greater ramet production than those in mid- and high-latitude gardens across the growing season, highlighting substantial phenotypic plasticity. The timing of the first ramet emergence showed a provenance-by-environment interaction, and was driven by abiotic factors at original sites. Furthermore, we found a generally negative covariance between ramet emergence time and ramet production, populations originating from low-latitudes consistently exhibited earlier ramet emergence with more ramets. Our findings suggest that clonal traits covariances were likely to benefit the local adaptation of S. alterniflora at low latitudes, and such covariances appeared to be driven by genetic admixture. Our study advances the understanding of how variable life-history strategies enable invasion success across environmental gradients in the introduced range, and highlights the need for region-specific management strategies tailored to local phenology.

Nonlinear response of soil microbial necromass nitrogen to nitrogen addition gradient in an alpine grassland
Quan-Cheng Wang, Jinsong Wang, Yang Li, Houkun Chu, Ronglei Zhou, Ning Liu, Mengjie Liu, Fangfang Ma, Chen Chen, Jingjing Shi, Huichen Zhang, Ruifa Wang, Shuli Niu
2026, 19 (4): rtag132.
doi:10.1093/jpe/rtag132
Abstract ( 42 )   PDF（pc） (1680KB) ( 6 )   Save
Microbial necromass nitrogen (N) constitutes a major component of soil N pools, and elucidating its response to N enrichment is essential for optimizing fertilizer management in grassland ecosystems. However, the effects of varying N addition levels on microbial necromass N and the underlying mechanisms remain elusive. Here, we leveraged a decade-long field experiment in an alpine meadow on the Qinghai-Tibetan Plateau (QTP), applying six N addition levels (0, 2, 4, 8, 16, 32 g N m^-2 yr^-1) to investigate the response of microbial necromass N and its key drivers. Microbial necromass N exhibited a nonlinear response to N enrichment, remaining stable under low N inputs (2, 4 and 8 g N m^-2 yr^-1) but increasing significantly at higher N addition levels (16 and 32 g N m^-2 yr^-1). Across all treatments, microbial necromass N accounted for 67%–76% of total soil N. Nitrogen-induced changes in plant, soil and microbial factors collectively explained 60% of the variation in microbial necromass N. Among these, soil factors were the dominant predictors, accounting for 34% of the total variance, with mineral protection (Fe_o + Al_o) and soil inorganic nitrogen (SIN) identified as the primary drivers. These findings highlight the pivotal role of microbial necromass N in soil N storage and its nonlinear response to N enrichment, underscoring the importance of effective N management for enhancing soil N retention and stability in alpine grasslands.

Short Communication

Physiological mechanism of leaf N:P ratio as the nutrient limitation diagnostic tool: from the perspective of P fractions
Jia Wang, Qingquan Meng, Jiashu Chen, Zhengbing Yan, Yaoqi Li, Wenxuan Han
2026, 19 (4): rtag012.
doi:10.1093/jpe/rtag012
Abstract ( 158 )   PDF（pc） (1257KB) ( 27 )   Save
Leaf nitrogen to phosphorus ratio (N:P) has widely been used to determine plant N and P limitations at community or larger scales. However, the underlying physiological mechanism of this rule of thumb has seldom been explored. Here, we quantify how leaf P fractions vary with leaf N:P and estimate the critical values and dynamics of leaf P fractions along the N:P gradient—from N limitation to P limitation, based on data collected from 143 unfertilized wild species in peer-reviewed literature. As leaf N:P increases, all P-fraction concentrations decline, with lipid P, inorganic P and residual P concentrations showing steeper declines than total P; the allocation-proportion ratios of metabolic P, nucleic acid P and lipid P shift from approximately ≤3:3:9 (corresponding to N:P ≤ 10), to 3:3:5 (N:P = 15) and to ≥3:3:3 (N:P ≥ 20). These findings suggest that most leaf P-fraction concentrations are more sensitive than total P to leaf N:P variations and reveal complicated P-use strategies of coordination (metabolic P and nucleic acid P) and trade-off (lipid P vs. metabolic P and nucleic acid P). This study provides a physiological explanation for using the leaf N:P ratio as a nutritional diagnosis and helps to better understand plant adaptive P-use strategies across diverse N and P availability conditions.

Special Issue: Clonal Plants as Agents of Change

Latitudinal growth and reproductive strategies of populations of Phragmites australis in estuaries
Tao Fang, Yi-Fan Liu, Yu-Han Chen, Yu Jin, Ting Wu, Ju-Juan Gao, Yao-Jun Zhu, Fang-Li Luo
2026, 19 (4): rtag029.
doi:10.1093/jpe/rtag029
Abstract ( 46 )   PDF（pc） (1586KB) ( 2 )   Save
Phragmites australis is a dominant species in estuaries. It can reproduce sexually and clonally. Understanding the latitudinal patterns of the traits can help in predicting adaptive strategies across environmental gradients. However, changes in growth and reproductive traits of P. australis, as well as growth-reproduction relationships along latitudinal gradients remain unclear. We sampled P. australis from five estuaries along latitudinal gradients in China and analyzed changes in growth, reproductive, and biomass allocation. The results revealed that with increasing latitude, the ramet height, flowering frequency, inflorescence biomass per flowering ramet, and weight of 100 seeds increased, whereas the ramet density generally decreased. The latitudinal growth and reproduction patterns were primarily influenced by variations in the temperature, precipitation, and light intensity. These results suggest that high-latitude P. australis populations may reduce their flowering and seed production under climate warming.