Xylem is essential for water and nutrient transport, mechanical support, and carbohydrate storage. Identification and quantification of vascular cell types remain manual, time-consuming, and prone to observer bias, limiting throughput and reproducibility. Automated, integrated tools are critical for scaling wood anatomical studies and enabling comparative analyses across taxa. We assembled a poplar xylem dataset of 1,790 microscopy images with 173,434 annotated instances. Using this dataset, we evaluated seven semantic segmentation models and five YOLOv8 detection models across section types for xylem cell recognition and morphometric attribute extraction and adopted a "Segmentation-then-Detection" pipeline to reduce misidentifications in complex backgrounds. Mask2Former achieved the best segmentation performance, covering transverse sections (whole xylem, vessels, fibers, rays) and tangential sections (rays and four ray cell image types). YOLOv8x and YOLOv8m performed consistently for object detection and morphometrics, and the PLXY-AI toolkit was accordingly developed based on YOLOv8 architecture. The combined pipeline markedly improved fiber identification in challenging images. In a generalization test, 34 of 42 woody angiosperms (81.0%) met >90% accuracy for identifying all cell types. The workflow and PLXY-AI toolkit enable automated identification and quantification of vessels, fibers, and rays, extracting size and area while substantially reducing manual workload and observer bias. Per-image processing time averages <1 s. Designed for batch analysis, the pipeline minimizes operational complexity and integrates easily into existing laboratory and computational environments. With a user-friendly graphical interface, this framework supports high-throughput analysis of vascular tissue structure and function across multiple tree species.

Thinning is widely applied in subtropical secondary forests, yet how its effects on soil nitrogen (N) differ across forest types remains unclear. We studied Pinus massoniana (conifer) and Quercus glauca (evergreen broadleaf) secondary forests in Hunan, China, under four thinning intensities (0%, 15%, 30%, 50%) using a randomized complete block design. Soil N pools—total nitrogen (TN), mineral-associated organic nitrogen (MAON), and dissolved organic nitrogen (DON)—were analyzed with linear mixed models, partial least squares regression (PLS-R), and structural equation modeling (SEM). N responses were strongly forest-type specific. In Quercus glauca, TN, MAON, and DON declined with increasing thinning intensity by up to 26.5%, 27.8%, and 51.4%, respectively. In Pinus massoniana, N pools remained stable across all intensities. Regulatory mechanisms diverged fundamentally. In Pinus massoniana, TN was governed by coupled interactions among soil carbon fractions, microbial biomass, and extracellular enzyme activities. In Quercus glauca, TN was regulated by a multivariate network in which fine-root N emerged as the key indicator. PLS-R explained 87.8% and 82.3% of TN variance, respectively. SEM confirmed that thinning affected Pinus massoniana N only through indirect carbon and phosphorus pathways (R2 = 0.88), while in Quercus glauca both direct (path coefficient = 0.39) and fine-root-mediated indirect effects operated (R2 = 0.61). Low-intensity thinning is therefore essential to preserve soil N retention in Quercus glauca forests, whereas Pinus massoniana forests tolerate a broader range of thinning intensities without compromising N pools.

Tire wear particles (TWPs), a major source of microplastic pollution, are mainly released in soils. TWPs are rubber-mineral composites that release evolving mixtures of metals, polycyclic aromatic hydrocarbons, and reactive additives and transformation products (e.g., N-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine-quinone). Unlike polymer-based microplastics, both TWP particle properties and leachate composition change with aging, potentially causing nonlinear toxic effects on ecosystems. Though TWPs are ubiquitous in terrestrial environments, their impacts on plant performance cannot be extrapolated from polymer-focused microplastic research. Here, we synthesize emerging evidence and propose a plant-centric, eco-evolutionary framework to explain how TWPs influence plants through soil-rhizosphere pathways. We emphasize three connected paradigms: (i) disentangling particle-driven physical effects on soil structure and root habitats from leachate-mediated chemical stress; (ii) integrating plant physiology, soil biogeochemistry, and pollutant chemistry to capture rhizosphere "hotspots" and microfood-web responses; and (iii) linking mechanistic understanding to exposure modeling, risk assessment, and policy. We organize TWP impacts as an inputs-processes-outputs chain, where dynamic exposure inputs (particle traits, mixtures, aging state, root-particle contact, etc.) regulate processes (chemical mobilization, microenvironment change, biotic interactions, etc.) and shape plant performance and plant-soil feedbacks. We propose testable hypotheses, including that weathering shifts dominant impacts from particle to leachate pathways and that root-particle interfaces create localized exposure gradients that restructure nutrient coupling and plant-microbe interactions. Finally, we outline research priorities such as aging-dependent and long-term assessments and interactions with co-occurring pollutants and global-change drivers to accelerate predictive understanding of TWP risks to soil-plant systems.

Forest biodiversity enhances ecosystem functionality and underpins sustainable forest management by improving soil nutrient cycling. As a representative sustainable management practice, tree species mixing (TSM) increases this functionality by regulating plant-soil nutrient interactions. This study compared the effects of TSM management on stand features, plant diversity, and soil microbial properties across different developmental stages of Cunninghamia lanceolata plantations. The results demonstrated that TSM management significantly enhanced the overall functional efficiency of the ecosystem. Specifically, TSM management improved stand features and reduced competition intensity among trees, which increased α-diversity of each vegetation layer while decreasing its β-diversity. Furthermore, TSM management increased litter layer thickness and soil available phosphorus content, with the magnitude of these effects varying across different management stages. Concurrently, although there was a reduction in α-diversity of bacteria (Chao1: −7.3%; Shannon: −2.7%), soil core microbial community exhibited an enrichment of oligotrophic bacteria (Acidibacter: +29.1%) and an increase in core fungal taxa, a shift that enhanced the decomposition of organic matter (litter thickness: +27.8%) and the transformation of nutrients (available nitrogen (N): +32.6%). Structural equation modeling (SEM) further confirmed that TSM management primarily drives soil carbon accumulation through the “tree diversity–core bacterial community–microbial biomass” pathway. In summary, this study reveals that TSM management promotes forest plant diversity and improves litter and soil conditions at the cost of reducing α-diversity and increasing the soil core bacterial community, ultimately leading to enhanced overall ecosystem functional efficiency. This finding provides important guidance for optimizing the structure, function, and resilience of degraded Chinese fir plantations, and offers a scientific basis for future decisions on balancing microbial community changes in the context of species diversity conservation and soil fertility restoration.

Drought and subsequent drought recovery affect alien plant invasion under global climate change. Plant lifespans (e.g., annuals and perennials) are a key feature associated with growth and reproductive strategies that may determine drought adaptation and invasion success of alien plants. However, little is known about how drought and drought recovery (i.e., rewetting) jointly affect the growth and reproduction of alien and native plants of different lifespans. We initially selected 16 native and 16 alien herbaceous species in China with different lifespans (annual and perennial), of which 30 species were included in the final experiment after two alien species were excluded because of poor germination. We then grew them individually under controlled water treatments (short-nondrought, short-drought, long-nondrought, long-drought and drought-rewetting). Overall, short-term drought caused a greater reduction in total biomass of alien plants than that of native plants, irrespective of lifespan. However, the difference in the responses of alien and native plants to prolonged drought depends on their lifespan. Following rewetting, alien perennial species showed greater growth recovery than native perennials. Additionally, rewetting promoted reproductive biomass of alien annuals compared to native annuals. Our study suggests a dual advantage in alien plants after drought: perennial species exhibited stronger growth recovery, whereas annuals showed a reproductive recovery superiority. These results suggest that post-drought recovery may contribute to alien plant performance under fluctuating water availability via lifespan-specific advantages, but further field and community-level studies are needed to evaluate whether this mechanism increases invasion risk.

Abstract Numerous studies have shown that elevated nitrogen (N) availability has facilitated plant invasion across many ecosystems. However, the impact of N forms on the invasion process remains unclear, particularly under varying N availability and competitive conditions. We grew five congeneric pairs of invasive and native species that are common in wetland and farmland ecosystems in the Southern part of China, under two levels of N availability (low vs. high) with different forms (ammonium [NH4+] vs. nitrate [NO3-] vs. organic [glycine]) that were fully crossed with competition (alone vs. interspecific competition). The results showed that under non-competitive conditions, neither invasive nor native species showed significant differences in performance among the different N forms. However, under competitive conditions combined with high N availability, invasive plants derived a specific advantage from NH4+-N, achieving greater growth than when supplied with NO3--N or glycine. In contrast, the performance of native species did not differ significantly across N forms under the same conditions. Under NO3--N supply, invasive species allocated more biomass to roots than native species did. This enhanced root allocation may improve invasive performance, particularly under high N conditions. Under low N availability, N form had no significant effect on biomass allocation for either invasive or native plants. The findings suggested that invasive species outperformed native species under both high NH4+-N conditions and competitive conditions. Results indicated that the risk of invasion may increase under scenarios of nutrient eutrophication and competitive interactions, particularly due to the substantial use of NH4+-N fertilizers in soil management in farmland or wetland ecosystems.

Thinning is widely used to regulate stand structure and soil nutrient cycle in subtropical secondary forests, yet whether its effects on soil nitrogen (N) depend on forest type and underlying pathways remains unclear. We investigated secondary stands dominated by Pinus massoniana and Quercus glauca in Hunan, China, under four thinning intensities (0%, 15%, 30%, and 50%) in a randomized block design. We quantified soil N pools—total nitrogen (TN), mineral-associated organic nitrogen (MAON), dissolved organic nitrogen (DON)—and applied linear mixed-effects models, multivariate analyses, and structural equation modeling to assess treatment effects and causal mechanisms. Soil N pools responded in strongly forest-type-specific ways. In Quercus glauca, TN, MAON, and DON declined markedly with increasing thinning intensity (≥15%), indicating high sensitivity. In Pinus massoniana, N pools were comparatively stable, showing only short-lived, recoverable shifts. Predictor analyses suggested contrasting regulation: TN in Pinus massoniana was dominated by belowground carbon processes (soil carbon fractions, microbial biomass carbon, and extracellular enzyme activities), whereas Quercus glauca showed multi-driver regulation, with fine-root N emerging as a key indicator of substrate quality. SEM further showed that thinning influenced soil N in Pinus massoniana only indirectly via carbon and phosphorus pools, with no significant direct path, while in Quercus glauca it exerted both direct and fine-root-mediated indirect effects. These results imply that conservative thinning is required to maintain N cycling in Quercus glauca forests, whereas Pinus massoniana forests can tolerate a broader range of thinning intensities.

Alien plant invasions in forests can severely threaten native biodiversity and ecosystem functioning. Canopy closure in deciduous forests can cause variability in light levels, but light levels in forest edges and evergreen forests are constantly high and low, respectively. We tested how light conditions and light variability affect invasiveness of alien plants by growing five pairs of invasive and noninvasive alien species under conditions of high, variable (with high light in the initial phase and low light in the latter phase of the experiment) and low light intensities. Total duration of the experiment was 200 days. The alien plants were grown singly, or competed with a native deciduous or evergreen tree seedling. Overall, invasive plants produced marginally more biomass than noninvasive plants. From high to low (averaged across variable and low) light conditions, biomass of invasive plants decreased less than that of noninvasive species (-26.7% versus -37.7%), indicating that invaders may have a greater capacity to invade forests than noninvasive plants. From low to variable light conditions, biomass of invasive plants increased more than that of noninvasive species (63.7% versus 48.9%), indicating that the advantage of invaders over noninvasive species is most pronounced under variable light conditions. Competition with the deciduous tree reduced biomass more for the noninvasive plants than for the invasive plants, indicating that interspecific competition may further explain why some alien species can invade while others cannot. Our results indicate that high light early in the season benefited more for the invaders, and reduced irradiance from the middle of the experiment limited growth of the noninvasive plants more than that of the invasive plants. Together, our results suggest that variable light levels, simulating those in deciduous forests or caused by disturbances, may promote the invasiveness of alien plants.

Plants' compensatory growth is the common response following grazing/mowing, particularly determined by the damage severity, availability of resources and plant functional types. Clonal plants exhibit unique clonal functional traits, yet the compensatory growth strategies underlying their responses to clipping intensity under various nitrogen (N) availability levels remain poorly understood. In this study, a pot experiment was conducted to test how the clonal plant species Leymus chinensis responds to clipping and N enrichment under heterogeneous soil conditions. Moderate clipping significantly enhanced the total biomass of younger ramets by 22% and 12%, under high and low N conditions, respectively, but had no impact on the total biomass of older ramets. The results suggested that L. chinensis exhibited over-compensatory growth characterized by prioritized biomass allocation to younger ramets rather than to older ramets, which facilitated its spatial expansion. However, severe clipping reduced the total biomass of younger ramets by 23%. Furthermore, the older ramets reduced biomass allocation to belowground parts and decreased the rhizome length (-28%), which negatively affected the growth of younger ramets. The younger ramets exhibited adaptation to clipping through the enhancement of antioxidant enzyme activities and the elevation of osmotic regulatory substance concentrations. N enrichment did not influence the total biomass of younger ramets or the entire clone. However, under moderate clipping, the biomass of older ramets increased relative to conditions without N enrichment. Our findings indicate that N availability affected the compensatory growth of the L. chinensis clone induced by clipping, thereby promoting the spatial expansion of this species. These results hold significant potential utilization of clonal plants for the restoration of patchy degraded grasslands. This study reveals the compensatory growth characteristics of the clonal plant Leymus chinensis in response to mowing and its regulatory mechanism under different nitrogen levels. The results show that moderate mowing induces over-compensatory growth, manifested as a preferential allocation of biomass to daughter ramets to promote spatial expansion, whereas severe mowing suppresses the growth of mother ramets and constrains daughter ramet development by reducing rhizome extension. While nitrogen addition did not significantly increase the overall biomass, it can influence the spatial expansion strategy of Leymus chinensis by modulating mowing-induced growth intensity, demonstrating potential application in the restoration of degraded grassland patches. (sic)(sic):(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)/(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)-(sic)(sic)(Leymus chinensis)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)((sic)(sic)(sic)(sic)(sic)22%, (sic)(sic)(sic)(sic)(sic)12%), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)23%;(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)28%, (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).

Plant invasions are increasingly being influenced by the complex interplay of global change factors (GCFs), notably biotic and abiotic stresses. However, how abiotic and biotic stresses affect the competitive performance of alien and native plants, as well as how phylogenetic relatedness regulates it, remains unclear. To test this, we selected six alien and six native confamilial plant species and grew them under abiotic (nutrient limitation) and biotic (enemy herbivory) stress treatments at three levels of plant interactions (no, intraspecific and interspecific). Herbivory more strongly reduced the biomass of native species than alien ones. Furthermore, under herbivory, alien species accumulated more biomass under interspecific competition than intraspecific competition, whereas natives exhibited no such difference. Meanwhile, alien plants had a greater positive correlation between biomass and phylogenetic distance than natives. We found that biotic stress favors aliens, particularly when they compete with distantly related plants. Our findings demonstrate that alien plants possess a competitive advantage over natives via biotic interactions, which is modulated by their phylogenetic distance. This advantage likely disrupts the coexistence of alien and native species, thereby facilitating the invasion of alien plants into biotically stressful environments.

Plant invasion is a major global driver to the structure of natural communities. Species diversity is a fundamental determinant of community regeneration through flowering phenology. However, the impacts of plant invasion on native plant flowering phenology and how species diversity regulates the process remain unclear. We conducted a field experiment to assess the effects of plant invasion (Solidago canadensis) and community species diversity on flowering phenology of native plants from different flowering functional groups at the community and species levels. At the community level, plant invasion shortened flowering duration and reduced flowering synchrony. Furthermore, high diversity reduced the negative impacts of plant invasion on flowering synchrony. Among flowering functional groups, the late- and mid-flowering species responded more negatively to plant invasion than the early-flowering species. Structural equation modeling indicated that plant invasion suppressed plant height and first or last flowering date by reducing light availability, which in turn affected flowering phenology. However, high diversity counteracted the negative effects. Our findings confirm the role of high diversity in resisting plant invasions on flowering phenology and reproduction of native plant communities, and suggest that high diversity with different flowering functional groups should be considered to efficiently restore native communities invaded by alien plants, such as S. canadensis.

The interplay between invasive alien plant species and various environmental change factors can lead to unpredictable ecosystem impacts. Existing research predominantly examines isolated or specific environmental factors, leaving the effects of complex, multifaceted environmental changes on the growth of both invasive alien and native plant species inadequately explored. Here, we investigated the biomass responses of ten confamilial‌ pairs of invasive and native species to six individual and combined environmental change factors. Our results revealed a significant reduction in biomass for both invasive and native species as the number of environmental change factors increased, with invasive species demonstrating heightened sensitivity. Notably, drought and salinity exhibited particularly severe negative effects across different environmental combinations, highlighting their critical role in driving these effects. Our findings underscore the importance of understanding and predicting how intensified environmental changes impact plant invasions and overall ecosystem stability.

Resource utilization is considered a crucial determinant of alien plant species in terrestrial ecosystems under abiotic and biotic conditions of global change. Alien plants are often favored over natives in stress-free or resource-rich ecosystems. However, certain resource-poor ecosystems have also been heavily invaded, particularly by legume woody species. How alien and native woody species compete in various abiotic and biotic stress environments and whether the functional traits associated with resource utilization promote their performance remain unknown. To test this, we grew six naturalized alien and six native woody species, grouped into three pairs of legumes and three pairs of nonlegumes, individually or in competition, under benign and two abiotic stress (drought, limited nutrients) and two biotic stress (aboveground enemies, belowground enemies) conditions. Overall, the four stress conditions had more negative effects on native plants than on alien ones, especially for nonlegumes under abiotic stresses. Moreover, when grown in competition, the presence of stress increased the growth asymmetry between alien and native plants in favor of the alien plants, but this was less pronounced in the legume group than in the non-legume group. Our study suggests that alien woody plants may have a competitive advantage over native ones under diverse abiotic and biotic stress conditions, but that this depends on their nitrogen-fixing ability. This is likely to affect the coexistence of alien and native woody species and may facilitate the spread of alien plants into stressful habitats.

Alien plant invasion is one of the key factors of global change. Soil legacies from previous plant species can affect the alien plants that are later introduced. Moreover, it is suggested that drought, as a common environmental factor, often influences plant–soil interactions. However, little is known about how drought and plant–soil feedback jointly affect the growth of subsequent alien and native plants of different lifespans. We conducted a two‐phase plant–soil feedback experiment. Firstly, we conditioned the soil using each of the 32 species (eight native annuals, eight native perennials, eight alien annuals and eight alien perennials) with or without drought treatment. Thereafter, each of the 20 species were grown on their conspecific and heterospecific soils to test the various soil legacy effects. Plants grew better in soil with heterospecific legacies than with conspecific legacies. The alien and perennial plants exhibited superior growth compared with the native and annual plants. Alien perennials achieved the relatively best growth in drought‐treated soils compared with all other plant species. Moreover, perennial plants were less negatively affected than annual plants when grown on drought‐treated soils conditioned by native species, particularly by native perennials. Our study suggests that alien perennials have an advantage in coping with the negative effects of complex soil legacies. This may accelerate the invasion process of communities and ecosystems dominated by perennials under drought conditions. Read the free Plain Language Summary for this article on the Journal blog.

Plant-earthworm interaction confers fitness advantages to the plants, including growth promotion, nutrient uptake, tolerance, and resistance to heavy metal (HM) contamination. Plant dominance and plant-soil nutrient cycle processes of plant invasion in contaminated environments can be mediated by plant-earthworm interaction. However, little is known about whether different functional groups of invasive plants can gain an advantage in HM-contaminated soils when regulated by plant-earthworm interaction. We conducted an experiment to examine the effects of Cadmium (Cd) (with or without) and earthworms (with or without) on the growth of both native and invasive species of legume, grass, and forb functional groups. We found that Cd reduced the biomass of native species and changed the root mass fraction and root-shoot ratio, while earthworms increased the aboveground mass of invasive species. When contaminated with Cd, earthworms increased the aboveground mass of invasive nonlegumes (grasses and forbs) while reducing the biomass loss of invasive legumes. In turn, invasive plants had a positive effect on earthworm mass. The mutually beneficial relationship between earthworms and invasive species in Cd-contaminated environments can enhance the competitive edge of invasive species over natives. This may facilitate invasive species spread, potentially risking Cd contamination and food chain transmission, threatening ecosystems biodiversity, environmental health, and human health. Thus, earthworm management may be an important measure to control the spread of invasive species in Cd-contaminated areas, particularly invasive nonlegumes.

Background & Aim:In response to the rapid global change,a growing number of species have been undergoing range shifts,which includes two main processes:one is the non-native species invasion mediated by human activities,and the other is the natural range expansion of native species.There are both similarities and differences between these two processes.It is thus critically important to distinguish their similarities and differences to develop scientific strategies for invasive species prevention and native species conservation. Progresses:By comparing the non-native species invasion and native species range expansion,we found that both non-native species invasion and native species range expansion are increasing under global change.However,there are obvious differences in potential drivers,spatial-temporal scales,occurring rates,species traits predicting the process,and impacts on new ranges between the two processes.The non-native species invasion usually occurs over long distance with the aid of human activity,spreads rapidly after establishment,high predictive ability of species traits,and poses a serious threat to local biodiversity.By contrast,range expansion of native species usually occurs at smaller spatial scales,slower occurring rates,and lower predictive ability of species traits,thus generally has less impacts on new regions. Prospects:As it is difficult to accurately determine the potential impacts of new-arrival species on recipient habitats,long-term monitoring and studies assessing the biological and ecological effects of these two processes on local population dynamics,community structure,and ecosystem function are needed,which is important to develop schemes of non-native species mitigation and native biodiversity conservation.

Climate dictates wildfire activity around the world. But East and Southeast Asia are an apparent exception as fire-activity variation there is unrelated to climatic variables. In subtropical China, fire activity decreased by 80% between 2003 and 2020 amid increased fire risks globally. Here, we assessed the fire regime, vegetation structure, fuel flammability and their interactions across subtropical Hubei, China. We show that tree basal area (TBA) and fuel flammability explained 60% of fire-frequency variance. Fire frequency and fuel flammability, in turn, explained 90% of TBA variance. These results reveal a novel system of scrubland–forest stabilized by vegetation–fire feedbacks. Frequent fires promote the persistence of derelict scrubland through positive vegetation–fire feedbacks; in forest, vegetation–fire feedbacks are negative and suppress fire. Thus, we attribute the decrease in wildfire activity to reforestation programs that concurrently increase forest coverage and foster negative vegetation–fire feedbacks that suppress wildfire.

Hard limestone substrates, which are extensively distributed, are believed to exacerbate drought and increase the difficulty of restoration in vulnerable karst regions. Fissures in such substrates may alleviate the negative effect of drought on plants, but the underlying mechanisms remain poorly understood. In a two-way factorial block design, the growth and photosynthesis of 2-year-old Phoebe zhennan seedlings were investigated in two water availabilities (high versus low) and three stimulated fissure habitat groups (soil, soil-filled fissure and non-soil-filled fissure). Moreover, the fissure treatments included both small and big fissures. Compared to the soil group, the non-soil-filled fissure group had decreased the total biomass, root biomass, total root length, and the root length of fine roots in the soil layer at both water availabilities, but increased net photosynthetic rate (Pn) and retained stable water use efficiency (WUE) at low water availability. However, there were no significant differences between the soil-filled fissure group and soil group in the biomass accumulation and allocation as well as Pn. Nevertheless, the SF group decreased the root distribution in total and in the soil layer, and also increased WUE at low water availability. Across all treatments, fissure size had no effect on plant growth or photosynthesis. Karst fissures filled with soil can alleviate drought impacts on plant root growth, which involves adjusting root distribution strategies and increasing water use efficiency. These results suggest that rock fissures can be involved in long-term plant responses to drought stress and vegetation restoration in rocky mountain environments under global climate change.

The invasion of alien plant species threatens the composition and diversity of native communities. However, the invasiveness of alien plants and the resilience of native communities are dependent on the interactions between biotic and abiotic factors, such as natural enemies and nutrient availability. In our study, we simulated the invasion of nine invasive plant species into native plant communities using two levels of nutrient availability and suppression of natural enemies. We evaluated the effect of biotic and abiotic factors on the response of alien target species and the resistance of native communities to invasion. The results showed that the presence of enemies (enemy release) increased the biomass proportion of alien plants while decreasing that of native communities in the absence of nutrient addition. Furthermore, we also found that the negative effect of enemy suppression on the evenness of the native community and the root-to-shoot ratio of alien target species was greatest under nutrient addition. Therefore, nutrient-poor and natural enemies might promote the invasive success of alien species in native communities, whereas nutrient addition and enemy suppression can better enhance the resistance of native plant communities to invasion.