Drought events and nitrogen deposition are substantially modifying the stability of terrestrial ecosystems. Previous studies have mostly investigated these factors separately, with an emphasis on productivity stability, leaving their combined effects on multiple dimensions of ecosystem stability poorly understood. We conducted a four-year grassland manipulative experiment to examine how three drought scenarios—intense drought, chronic drought, and precipitation frequency reduction—interact with nitrogen addition to influence community compositional stability and productivity stability. The results showed that drought and nitrogen enrichment independently influenced grassland stability without significant interactions. Both intense and chronic drought reduced productivity stability, while reduced precipitation frequency decreased compositional stability. Nitrogen addition decreased both types of stability. Productivity stability was driven by the dominant species’ productivity stability or a combination of it and species asynchrony, depending on the drought scenario. Compositional stability consistently depended on the dominant species’ compositional stability. Compositional and productivity stability remained decoupled across treatments. This study provides the first empirical evidence of the divergent responses of grassland compositional and productivity stability to various drought scenarios under nitrogen enrichment. Our findings highlight the importance of prioritizing dominant species and promoting species coexistence with diverse environmental responses to maintain stable grassland composition and productivity under global change.

CO₂ released into the atmosphere through soil respiration represents the second-largest carbon flux between terrestrial ecosystems and the atmosphere. While extensive research has concentrated on surface soils, limited studies have explored CO₂ emission patterns and their primary drivers across varying soil depths. In this study, soil CO₂ emissions were measured using static chambers at six different depths (10, 50, 100, 200, 300 and 400 cm) in a primary forest. Additionally, potential influencing factors, including soil physical and chemical properties, microbial diversity and community structure and function, were assessed. The results demonstrated that soil nutrients, along with fungal and bacterial diversity, generally declined with increasing soil depth. Soil CO₂ emissions also decreased significantly with depth, driven primarily by biotic factors such as fungal and bacterial alpha diversity and abiotic factors such as ammonium nitrogen and available phosphorus. These findings provide new insights into the mechanisms of carbon cycling within deep soil layers in forest ecosystems.

In water-limited ecosystems, photodegradation is a dominant pathway of carbon (C) turnover. However, the combined effects of spectral composition and litter traits in hyper-arid deserts remain poorly constrained, limiting the accuracy of C flux predictions. In a 637-day field experiment with three representative desert species (Populus euphratica, Alhagi sparsifolia and Karelinia caspia), we applied natural light filters to establish six spectral treatments. Full-spectrum exposure increased litter decomposition by 70%; of the five individual wave-bands, only UV-B (280–315 nm) and blue light (400–500 nm) significantly accelerated mass loss, accounting for 43% and 29% of the full-spectrum effect, respectively. These two wave-bands accelerated C and cellulose loss, whereas green light (500–580 nm) selectively promoted hemicellulose and lignin degradation without affecting total mass. UV-B and blue light also increased specific leaf area (SLA) by 12.9% and 7.0% and elevated litter microbial respiration rate (LMR, 24-h incubation at 25 °C, 60% relative humidity) by 54.6% and 40.6%, respectively. Across four spectral regions, initial C content, lignin:N ratio, SLA and LMR were significantly correlated with photodegradation rate, with LMR and lignin content per unit surface area being the strongest predictors of susceptibility. These results highlight the co-regulation of photodegradation by spectral composition and plant traits, advancing mechanistic understanding of C cycling in hyper-arid ecosystems and providing refined parameters for Earth system models changing solar regimes.

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.

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.

Extreme climatic events often co-occur with persistent environmental disturbances, such as nitrogen enrichment, which may influence the resistance and recovery of plant communities to extreme climatic conditions. However, most studies have focused on the resistance and recovery of community functions (e.g. biomass) to climatic events while neglecting the corresponding responses of diversity. Here, we performed a soil nitrogen addition experiment in an alpine meadow from 2011 to 2020, with 2015 characterized by extreme drought. We explored the effects of nitrogen addition on the resistance and recovery of plant community biomass and diversity in response to extreme drought using measures including community biomass, taxonomic diversity (TD), phylogenetic diversity (PD) and functional diversity (FD). We found that nitrogen addition decreased biomass resistance, mainly due to species asynchrony rather than the diversity resistance, even though PD and FD resistance also declined. Meanwhile, nitrogen addition enhanced the recovery of biomass to drought. This was mainly attributable to the direct, positive impact of nitrogen on biomass recovery, coupled with an indirect influence of species asynchrony, without any diversity (TD, PD, FD) recovery effects. Our results indicate that soil nitrogen enrichment mainly influences plant biomass responses to extreme drought, with a relatively small effect on plant diversity. Additionally, the mechanisms driving diversity and biomass responses may operate independently, as changes in diversity response did not scale up to changes in biomass. We anticipate that maintenance of plant community biomass during extreme drought would be more challenging in conditions of high nitrogen deposition.

Herbivorous insects shape plant growth and community assembly, while conversely, plant traits, especially leaf traits, profoundly affect herbivore behaviors. However, which leaf traits and how they dominantly drive insect herbivory in a natural forest habitat remain undefined. In this study, we evaluated the background insect herbivory of 45 individual trees from five broadleaved tree species in the northeast of China. Based on that, 17 leaf traits representing four groups—leaf structural traits, photosynthetic pigments, nutrient traits, and secondary metabolites—were measured. Finally, the correlation between 17 leaf traits and background insect herbivory was investigated. The results indicated that the damaged leaf area (DLA) exhibited positive correlations with leaf structural traits (leaf mass per area and leaf size) and nutrient traits (soluble sugar (SS), non-structural carbohydrates (NSC), SS/NSC), and a negative correlation with photosynthetic pigments, nitrogen/phosphorus ratio, and anthocyanins. Meanwhile, SS/NSC, SS, leaf size, total phenol, and phosphorus were identified as the five relatively important leaf traits contributing to DLA by the quantitative estimation based on SHAP (SHapley Additive exPlanations) values. Furthermore, nutrient traits accounted for 52.9% of DLA explanation, showing the most important group of leaf traits. In addition, structural traits and secondary metabolites were found to interactively influence herbivory. These findings provide valuable insights into the complex interactions between host plants and herbivorous insects in forest ecosystems.

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.

Arbuscular mycorrhizal fungi (AMF) can enhance terrestrial plant growth by promoting nutrient uptake. However, the effects of interactions between AMF and nutrient inputs on plant functional traits and their trade-offs remain poorly understood. In this study, a pot experiment was conducted using Phragmites australis as the host species, with AMF inoculation and non-inoculation treatments under three levels of nitrogen addition and two levels of phosphorus addition. The results showed that AMF inoculation significantly increased AMF colonization in the roots of P. australis. Under unfertilized conditions, AMF significantly promoted plant morphological development and biomass accumulation. Nitrogen addition primarily enhanced aboveground growth, while phosphorus addition significantly stimulated root system development. Regarding photosynthetic traits, AMF inoculation significantly increased carotenoid content, whereas phosphorus addition significantly reduced net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) by 18.5%, 25.8%, and 28.2%, respectively. Furthermore, AMF inoculation increased leaf nitrogen and phosphorus contents but reduced stem nitrogen content and the N:P ratios in fine roots, rhizomes, and stems. Trait network analysis revealed that AMF inoculation shifted the central traits from leaf biomass to rhizome biomass, indicating a transition in hub traits from aboveground to belowground organs. These findings suggest that AMF inoculation significantly promotes the growth of P. australis although the magnitude of this benefit is modulated by soil nitrogen and phosphorus availability, with stronger effects observed under nutrient-poor conditions. This study advances our understanding of nutrient–AMF–plant interactions in wetland ecosystems and provides a theoretical foundation for ecological restoration and nutrient management in vulnerable aquatic habitats.

As global warming drives plant upward migration, the alpine tundra of Changbai Mountain is experiencing encroachment by Deyeuxia angustifolia (Komarov) Y. L. Chang, a low-elevation herb. However, its impact on native shrubs such as Rhododendron aureum Georgi remains unclear. Here, we analyzed the radial growth trends and climate sensitivity of R. aureum across elevations and encroachment gradients using linear and mixed-effects model methods, and explored the mediating roles of soil properties and plant traits. Our study revealed that R. aureum exhibited stronger positive long-term growth trend at higher elevations compared to lower elevations. Mild and moderate encroachment of D. angustifolia enhanced the positive growth trend of R. aureum, especially at the low elevations. Moreover, R. aureum showed weak climate sensitivity at mid-elevation but stronger responses to winter temperatures at low elevation and to spring–summer temperatures and precipitation at high elevation. D. angustifolia encroachment further intensified this sensitivity, characterized by stronger negative responses to spring, autumn, and winter temperatures but positive responses to summer temperatures and autumn precipitation. Overall, elevation primarily influenced R. aureum growth and its sensitivity to precipitation through soil conditions and plant size traits. Soil conditions and leaf economic traits influence temperature sensitivity. These findings advance understanding of alpine vegetation dynamics and contribute to ecosystem conservation under climate change.

Despite nitrogen (N) and phosphorus (P) being biologically coupled and controlling many biochemical reactions, few studies have examined the N:P patterns and controls of legumes and non-legumes at a global scale. Herein, we explored how the ratio of N and P in legumes and non-legumes responds to environmental factors, globally. Our results indicated that legumes exhibited stronger N-P coupling (R² = 0.39, P < 0.0001) in warm-humid environments (mean precipitation: 988.94 mm, temperature: 12.63 °C), and the N:P is negatively affected by the soil total P (scored at = −0.25). In contrast, non-legumes were more flexible in N and P (R2 = 0.23, P < 0.0001) in semihumid regions (precipitation = 785.01 mm, temperature = 8.85 °C), where soil total N (scored at = −0.22) and biodiversity (scored at = 0.16) emerge as dominant drivers for the N:P. Although legumes are expected to be more soil P-limited, our findings revealed that the leaf N and P were more coupled in legumes than in non-legumes, which offers a unique perspective on resource utilization and survival strategies in different plant functions.

Leguminous species have an advantage in acquiring phosphorus (P) compared with non-leguminous species. Nonetheless, it remains unclear whether this advantage would diminish under long-term nitrogen (N) deposition. In the seventh year of a simulated long-term N deposition experiment, we sampled surface soil to measure acid phosphatase activity (ACP) in stands dominated by leguminous and non-leguminous species, respectively. To assess the response of ACP to prolonged N addition, we also collected data on ACP in the second, eighth, twelfth, and thirteenth years of the experiment. We found that the difference in soil ACP between the two plantation types disappeared after long-term N input, and this process was accelerated under high N addition. This occurred due to an exacerbated P-limitation, which primarily prompts ACP production only in non-leguminous species. Additionally, there was a relatively decreased N contribution efficiency to ACP in the stand with leguminous species, indicating that soil N content no longer primarily governs ACP. This study demonstrates that prolonged high N deposition accelerates the loss of the “P-acquiring advantage” in leguminous plantations. To elucidate the differences in P usage strategies between leguminous and non-leguminous species under global change, more systematic research is warranted in the future.