Aims Investigating the species diversity of naturally regenerated understory vegetation in different exotic plantations within the National Park of Hainan Tropical Rainforest, and identifiy the dominant factors affecting variation in species composition. Methods A total of 173 plots (20×20 m) were established in Mt.Jianfengling section of National Park of Hainan Tropical Rainforest, including three exotic plantation types (Eucalyptus urophylla, Acacia mangium, and Pinus caribaea) and natural tropical lowland rainforests. In each plot, all woody individuals with a diameter at breast height (DBH)≥1cm were surveyed and environmental variables were sampled. The non-parametric tests (Kruskal-Wallis and Dunn’s test) were applied to compare stem density, basal area, and species richness across three DBH classes. Dominant species were identified based on importance value, and indicator species were identified using Indicator Species Analysis (ISA). Variation in species composition among forest types were examined by using similarity analysis and nonmetric multidimensional scaling (NMDS). Permutation tests were conducted to assess the effects of different varied environmental factors on variation in community composition. Important findings Eucalyptus urophylla plantations had the lowest species richness (30 ±1 species) but the highest stem density (392 ±13 individuals). In contrast, the species richness (47±1 and 42±1 species) and stem density (291±16 and 262±12 individuals) of A. mangium and P. caribaea plantations did not differ significantly from those of natural forests (54±3 species, 214±31 individuals). Naturally regenerated vegetation understory of plantations generally lacked large-diameter individuals (DBH≥10 cm). The understorey of E. urophylla plantations was dominated by Alchornea rugosa, whereas A. mangium and P. caribaea plantations had no particularly dominant species. Species composition differed significantly among forest types: E. urophylla plantations showed the lowest similarity to natural forests, while A. mangium and P. caribaea plantations exhibited greater similarity but still differed notably from natural forests. Soil pH, total nitrogen, total available phosphorus, available potassium, elevation, stand age, and basal area of planted species were the main environmental drivers to determine species composition . Conclusion For exotic species plantations in the National Park of Hainan Tropical Rainforest, future management should prioritize optimizing stand structure and promoting the growth and succession of small diameter individuals of native species to facilitate their transition into larger size classes. Given the variation in natural regeneration among plantation types, specific restoration strategies should be developed for each forest type.

Xiaowutai Mountain, located at the junction of the Taihang, Yanshan, and Hengshan ranges, represents a typical temperate montane forest ecosystem in North China and serves as an important ecological barrier for the Beijing–Tianjin–Hebei region. To fill the gap in systematic vegetation survey data, we conducted a plot-based survey during the 2025 growing season following unified technical protocols. A total of 67 plots were established along an elevation gradient and across different slope aspects to record community structure, species composition, and environmental variables; vegetation types were then classified and named, and the records were integrated into a vegetation plot dataset for the Xiaowutai National Nature Reserve. We documented 321 vascular plant species belonging to 197 genera and 69 families, with Asteraceae, Rosaceae, and Poaceae as the dominant families. By life form, there were 225 herbs (70.1%), 58 shrubs (18.1%), 23 trees (7.2%), and 7 species of ferns and lianas combined (2.2%), plus a single subshrub species. The vegetation was categorized into three vegetation formation groups, seven vegetation formations, and 36 associations, which together essentially cover the spatial distribution range of the major vegetation types in Xiaowutai Mountain. This dataset provides reusable baseline information for vegetation classification, community comparisons, and conservation zoning in Xiaowutai Mountain.

Aims Germination timing determines the environmental conditions experienced after germination, holding significant adaptive significance. Plant populations can exhibit distinct patterns of germination timing along environmental gradients, and germination timing within populations responds to environmental change. Spartina alterniflora has rapidly expanded into temperate, subtropical, and tropical regions since it was introduced to China in 1979. At mid and high latitudes, it typically germinates in spring. However, populations along a latitudinal gradient have developed differentiated germination timing by adapting to local environmental conditions. Few studies have examined how seasonal germination characteristics vary among populations along the latitudinal gradient. Methods In this study, we collected seeds from nine populations along the latitudinal distribution range of S. alterniflora and sowed them in multiple common gardens across three different climate zones. Seed germination dates were continuously monitored to explore how seasonal germination characteristics responds to both the planting and seed source environmental conditions. Important findings (1) As the latitude of common gardens decreased, winter temperatures significantly increased. Consequently, the germination window of S. alterniflora expanded from exclusively spring to both winter (earlier) and spring. Accompanied by increased winter germination percentage (P < 0.05) and decreased spring germination percentage (P < 0.05), the proportion of winter-germinated significantly increased (P < 0.05), while the total germination percentage declined (P < 0.05). (2) Within each common garden, winter germination percentage did not change across populations along a latitudinal gradient; however, spring germination percentage decreased significantly with decreased latitude of origin (P < 0.001). Specifically, in the mid-latitude and low-latitude common gardens, the proportion of winter-germinated showed a significant negative correlation with the latitude of origin (P < 0.05). (3) As the temperature at sites of origin increased, the total germination percentage significantly decreased (P < 0.001), and the proportion of winter-germinated significantly increased (P < 0.001). Overall, both increased temperature of the planting environments and the source environments enhanced the likelihood of germinating in the current winter but reduced the total germination percentage, indicating that temperature is a key factor influencing the seasonal germination characteristics across latitudinal populations of S. alterniflora. These findings provide a scientific basis for predicting changes in the germination strategies of S. alterniflora along the latitudinal gradient under climate warming, which is crucial for forecasting shifts in the fitness and distribution range of S. alterniflora.

Aims Environmental gradients and human disturbance are key drivers affecting soil microbial communities and biodiversity, yet their combined effects on soil legacy processes and subsequent plant growth remain poorly understood. Methods We conducted a study in the Shennongjia region of Hubei Province, China. Plots characterized by three disturbance levels—Low, Medium, and High disturbance—were established along an elevational gradient ranging from 500 to 3000 m. By combining field sampling with a greenhouse common garden experiment, we systematically evaluated the impacts of elevational gradients and human disturbance on soil microbial communities and the resulting soil legacy effects on plant growth. Important findings Elevation significantly reduced the α-diversity of soil bacteria and fungi and markedly altered microbial community composition, whereas the direct effects of human disturbance on microbial community structure were relatively weak. Soil legacy effects varied significantly across human disturbance levels, with medium disturbance markedly amplifying the positive effects of soil legacies on plant total biomass, while these effects weakened or became neutral under low and high disturbance conditions. The legacy effects on the root-to-shoot ratio showed a significant interaction between elevation and disturbance, indicating that the response of plant resource allocation strategies to soil historical conditions is strongly environmentally dependent. Structural Equation Modeling (SEM) further revealed that elevation indirectly influenced plant traits primarily through its effects on fungal communities, while interactions between fungal and bacterial communities regulated the direction and magnitude of soil legacy effects. Overall, soil legacy effects serve as a key mechanism linking elevational gradients, human disturbance, and plant growth responses, with their ecological importance being particularly pronounced under medium disturbance conditions. This study highlights the necessity of incorporating soil legacy effects when predicting subtropical mountain vegetation dynamics in the context of global change.

Aims Numerous simulation experiments have shown that increased atmospheric acid deposition could lead to the increase of phosphorus limitation of soil microbes. However, there is a lack of in-depth analysis of how acid deposition affects microbial element limitation around industrial acid emission sources, especially in areas with severe soil salinity-alkalinity. Methods Taking three power plants in the Ningdong Energy and Chemical Industry Base as the monitoring sites, this paper analyzed soil enzyme ecological stoichiometry and explored the microbial element limitation and its influencing factors around industrial acid emission sources. Important findings The results showed that the ranges of carbon-acquiring enzyme activity (C_E), nitrogen-acquiring enzyme activity (N_E), phosphorus-acquiring enzyme activity (P_E), lnC:N_E, lnC:P_E, and lnN:P_E were 3.31~59.92 nmol·g^⁻1, 4.24~125.95 nmol·g^⁻1, 3.62~189.46 nmol·g^⁻1, 0.48~1.47, 0.32~1.41, and 0.56~1.18. Nitrogen and sulfur deposition did not affect the enzyme vector length and angle (p > 0.05). Ca²⁺ and K⁺ deposition positively influenced the vector length (p < 0.05) by a direct approach or by indirect approaches, soil physiochemical properties (electrical conductivity, available phosphorus, Na⁺, Mg²⁺, etc.), plant traits (total phosphorus and N:P) and microbial characteristics (biomass carbon and nitrogen). Ca²⁺ and Na⁺ deposition positively influenced the vector angle (p < 0.01) by affecting soil physiochemical properties and plant traits. In summary, microbes are mainly limited by phosphorus in the study area; nitrogen and sulfur deposition does not alter microbial element limitation. In contrast, base cation deposition could enhance microbial carbon and phosphorus limitation by aggregating soil salt stress, reducing soil phosphorus availability, and triggering phosphorus competition between plants and microbes.

Aims The aim of this study is to explore the characteristics of soil seed banks in typical shrub communities in Luoshan, Ningxia, and their relationship with aboveground vegetation. The study also evaluates the ecological restoration potential of soil seed banks and clarifies their role in vegetation restoration. Methods In this study, six typical shrub community sample plots were set up in Luoshan Nature Reserve of Ningxia Province, and the method of field investigation and sampling and germination experiment was adopted. Important finding A study found that a total of 82 plant species belonging to 31 families and 64 genera were counted in the aboveground vegetation of 6 typical shrub groups. The life form of the species is mainly composed of perennial herbaceous plants, followed by shrubs, and the proportion of annual plants is relatively low; The species richness of the tiger hazelnut community is the highest and the distribution is relatively uniform, while the species richness of the thorn spiral flower community is the lowest and the distribution is uneven. There are a total of 43 plant species in the soil seed bank of 6 typical shrub communities, belonging to 17 families and 35 genera. The life forms of these plants are mainly perennial herbs. The density range of soil seed banks for 6 plant communities is 1033.33 ± 57.74 (grains/m2) -7000.00 ± 200 (grains/m2). The soil seed density is highest in the community of mutual leaved drunken fish grass, and lowest in the community of spiny spiral flowers; Most of the seeds in each plant community are concentrated in the 0-10cm soil layer. As the soil layer deepens, the density and number of species in the soil seed bank of each plant community show a decreasing trend; Overall, the species diversity index of the tiger hazelnut and mutual leaved drunken fish grass communities is the highest, while the thorn spiral flower community is the lowest. The vegetation on the ground of six typical shrub groups is higher in terms of plant species and quantity than in the soil seed bank, and the uneven distribution of plant species in the soil seed bank is more pronounced than in the above ground vegetation. The similarity between aboveground vegetation and soil seed banks in various plant communities is relatively low, with a similarity index range of 0.286-0.444. The evaluation of the ecological restoration potential of soil seed banks shows that the ecological restoration potential of the tiger hazelnut community is strong, while the ecological restoration potential of the other five typical shrub communities is moderate. Overall, although soil seed banks provide a certain source of seeds in vegetation restoration, relying solely on natural seed banks is not sufficient to fully meet the ecological restoration needs. In the actual production process, corresponding restoration measures need to be adopted based on the characteristics of different plant communities, and moderate human regulation should be carried out to promote community succession in the direction of progress or increasing biomass.

Aims In order to accurately assess the impact of drought events on the function of forest carbon sinks, this paper explores the occurrence and persistence of the drought legacy effect at different altitude gradients based on tree radial growth data. Methods In this paper, we take Picea schrenkiana as the dominant tree species in the Ili River Basin in the western Tianshan Mountains of Xinjiang, quantify the drought legacy effect of Picea schrenkiana at different elevations (2100, 2300 and 2500 m a.s.l.) by using ARIMA.We compared and analysed the differences in the duration and degree of the drought legacy effect of Picea schrenkiana at different altitudes, and revealed the changing law of the drought legacy effect of Picea schrenkiana at different altitudes and its driving factors. Important findings The results showed that (1) the radial growth of Picea schrenkiana at all three elevations was significantly positively correlated with the precipitation and PDSI of last year's growing season, suggesting that drought stress strongly limited the radial growth of trees. (2) With the increase of elevation, the duration of drought legacy decreased. The drought legacy effect of Picea schrenkiana existed for 2 years at low elevation, but only existed for 1 year at middle and high elevation. The recovery and resilience of Picea schrenkiana to drought events at low elevation were lower than those at medium and high elevation（P＜0.05）..(3) The effect of drought legacy and the cumulative drought legacy are low elevation＞middle elevation＞high elevation,and the drought legacy effect of each elevation was the greatest in the first year after the end of drought.After several drought disturbances, the cumulative drought legacy effect and the percentage of trees with drought legacy effect showed a tendency of decreasing and then increasing.Therefore, the recovery and resilience of trees to drought events and the frequency of droughts are all important factors that contribute to the elevation differences of the Picea schrenkiana drought legacy in western Tianshan.

Aims The biodiversity-ecosystem function relationship is a prominent research topic within ecology. In the context of global environmental changes, biodiversity loss may constrain ecosystem functioning. Most existing studies focus on diversity effects on individual functions (e.g., productivity, carbon sequestration, etc.) or ecosystem multi-functionality (EMF), while overlooking the interactions among different ecological functions - a phenomenon quantified as ecosystem coupling. To date, it remains elusive how diversity changes impact ecosystem coupling and the relationships between EMF and ecosystem coupling. Methods Using standardized field surveys across 40 sampling sites across the Tibetan alpine grasslands, we explored the large-scale patterns of ecosystem multifunctionality and ecosystem coupling, and their relationships with plant diversity. Important findings The EMF exhibited highly spatial heterogeneity, while ecosystem coupling showed less variation at the regional scale. Meanwhile, no significant correlation was observed between EMF and ecosystem coupling. The EMF was significantly correlated with climatic factors, plant diversity, and soil properties, whereas ecosystem coupling remained insensitive to variations in both biotic and abiotic drivers. These results reveal a widespread decoupling between EMF and ecosystem coupling at the large scale, not supporting the notion that higher EMF associated with stronger ecosystem coupling based on controlled experiments. Our findings provide new insights into the relationship between biodiversity and ecosystem functions, and also lay a theoretical base for achieving the national strategy of "integrated management of mountains, waters, forests, farmlands, lakes, grasslands and deserts " via biodiversity conservation.

Aims The response of forest soil organic carbon (SOC) to global change has remained a prominent frontier issue in ecological research. Although numerous studies have demonstrated that nitrogen deposition can promote the accumulation and of forest SOC and enhance its stability, the impact of nitrogen deposition on the accumulation process of specific plant-derived components in SOC, such as lignin phenols, remains unclear. This knowledge gap limits our in-depth understanding of forest carbon cycling processes and their pivotal role in maintaining global carbon balance. Methods Based on the long-term (more than 20 years) nitrogen deposition experimental platform in Dinghu Mountain（112° 10′ E, 23° 10′ N）, this study systematically investigated the effects of long term nitrogen addition on the accumulation patterns of lignin phenols across different soil layers and their underlying mechanisms. Important findings The results indicated that: (1) Lignin phenol content significantly decreases with soil depth; Nitrogen addition increased lignin phenol content by 23.7% in the 0-10 cm soil layer but had no significant effect on the 10-30 cm layer. (2) Under the control treatment, the activity of C-degrading enzymes is a key factor influencing lignin phenol accumulation; Nitrogen addition inhibited C-degrading enzyme activityand weakened their regulatory effect on the accumulation of lignin phenols. However, lignin phenols were more effectively protected through physical and chemical binding with soil minerals, thereby significantly reducing their bioavailability. In summary, the impact of long-term nitrogen deposition on plant-derived carbon in tropical forests exhibits significant soil layer dependency, with its effects limited to promoting lignin phenol accumulation in the surface soil layer. long term high nitrogen input has altered the regulatory pathways of plant-derived carbon accumulation in tropical evergreen broadleaf forest soils, shifting from microbial degradation processes to physicochemical protection as the dominant mechanism. This study unveils a novel mechanism for maintaining the stability of tropical forest soil carbon pools under nitrogen deposition, providing crucial theoretical insights for predicting forest soil carbon dynamics.

Aims Large-scale Chinese fir (Cunninghamia lanceolata) plantation management has caused severe forest nutrient imbalance in subtropical regions. Transforming stands by increasing tree species diversity is an important approach to mitigate nutrient imbalance in Chinese fir plantations. However, the effects of neighbourhood tree species richness on litter nutrient concentrations and their stoichiometric characteristics remain unclear. Methods This study established gradients of neighbourhood tree species richness (1, 4, 6, 7, and 8 species) to investigate their effects on the concentrations of carbon (C), nitrogen (N), and phosphorus (P) and the stoichiometric characteristics of Chinese fir litter in subtropical plantations. Important findings The results showed that litter N and P concentrations increased by 37.1% and 45.9% at richness levels of 6 and 7 species, respectively, compared with the monoculture treatment. This increase resulted in significant reductions in litter C/N and C/P, by 26.9% and 31.5%, respectively. Soil nitrate nitrogen was positively correlated with litter N concentration and negatively with litter C/N. Soil available phosphorus was significantly positively correlated with litter P concentration, resulting in a significant negative correlation with litter C/P. The best-fitting linear mixed-effects models showed that soil available phosphorus and pH were the main factors explaining variation in litter P concentration and C/P. Therefore, these findings suggest that a moderate increase in neighbourhood tree species richness enhances litter nutrient concentrations in the target tree species and reduces its carbon-to-nutrient stoichiometric ratios, thereby promoting litter nutrient return and improving forest nutrient status in Chinese fir plantations.

Aims Microplastic pollution and multispecies invasions are escalating global threats to native plant communities. However, how plant communities respond to microplastics in the context of multispecies invasions, and the mechanisms driving these responses, are still largely unknown. To address this gap, we conducted a controlled experiment. Methods We established synthetic plant communities composed of three grass species, three legume species, and three invasive species along a 12-level abundance gradient of polypropylene microplastics. To elucidate the underlying ecological drivers, we measured soil physicochemical properties, community-level fluorescence traits, species richness, community biomass, and species relative abundance. Furthermore, structural equation modeling was used to identify key pathways. Important findings (1) Overall, polypropylene (PP) microplastics significantly decreased plant species richness, especially at intermediate levels, without a consistent monotonic trend. (2) Unlike plant species richness, PP microplastics did not decrease overall community biomass, and community biomass exhibited a U-shaped response, decreasing at low to medium microplastic levels and increasing significantly at high levels. (3) PP microplastics had no significant effect on the relative abundance of invasive plants, but significantly affected community-level fluorescence traits, and soil phosphorus and potassium. Structural equation modeling revealed distinct pathways by which microplastics influenced plant species richness, invader relative abundance, and community productivity. These findings suggest that microplastics could regulate plant diversity and community productivity primarily by altering soil nutrient availability and plant functional traits. Furthermore, soil nutrients and pH could exert contrasting influences on invasion processes under microplastic stress.

The soil seed bank, as a "storage" of aboveground vegetation species diversity, is the material foundation for plant community renewal and succession and a core driving force for regional vegetation natural restoration. This review, based on recently published high-impact studies, systematically summarizes the dynamic characteristics and driving mechanisms of soil seed banks in community succession, the impact pathways of disturbances on seed banks, and the application potential and limitations of seed banks in ecological restoration.The study found that the seed bank density, species richness, and composition show regular changes across succession stages, with high seed density in early stages, high richness in mid-stages, and low similarity in late stages as cross-system common characteristics; Disturbances affect seed bank functions through direct (e.g., climate change, physical disturbances), indirect (e.g., habitat changes, intensified competition), and cross-scale pathways (e.g., temporal mismatches, spatial diffusion), with multi-path interactions leading to nonlinear responses; Although seed banks provide a source of seed for the restoration of degraded ecosystems, their application is limited by the availability of target species seeds and environmental stress. Future research should focus on strengthening long-term monitoring, analyzing multi-factor interaction mechanisms, and developing precise restoration technologies based on seed bank characteristics to address ecological restoration challenges under global change.

Aims Interspecific competition is a key process regulating plant community assembly and productivity, and nitrogen and phosphorus availability are major factors influencing interspecific competitive interactions among wetland plants. However, systematic understanding of the differences between aboveground and belowground competition, especially under nitrogen and phosphorus enrichment conditions, remains limited, hindering predictions of wetland community dynamics. Methods We conducted a greenhouse experiment with two plant species, coexisting and habitat-similar dominant perennial species in the Poyang Lake, Carex cinerascens and Phalaris arundinacea. Experimental treatments included four competition treatments (no competition, aboveground competition [AGC], belowground competition [BGC], and both competition) and four nutrient conditions (control, nitrogen addition [N], phosphorus addition [P], and combined nitrogen–phosphorus addition [NP]). Aboveground and belowground biomass of both species were measured under each treatment to evaluate biomass allocation strategies. Relative interaction index (RII) under different nutrient conditions were calculated to assess the effects of nutrient inputs on interspecific competition. Important findings 1) BGC was the primary driver of growth and biomass allocation, with C. cinerascens showing a strong BGC advantage and maintained overall dominance by allocating more biomass to aboveground parts, whereas P. arundinacea was suppressed by BGC and allocated more biomass to belowground parts to alleviate this suppression; 2) N addition reduced the BGC advantage of C. cinerascens, P addition alleviated the suppressive effects of BGC to P. arundinacea, and NP addition enhanced its competitive advantage while reducing inhibition of P. arundinacea, resulting in increased total biomass; 3) The effects of nutrient inputs on interspecific competition were primarily driven by interactive effects of AGC and P addition on belowground biomass, and by interactive effects of BGC and N addition on aboveground biomass. Conclusions Nutrient addition can alter interspecific competitive relationships between plant species, but only synchronous changes in nitrogen and phosphorus availability can enhance total biomass while maintaining table biomass proportions between the two species . Therefore, under future nutrient-enrichment scenarios, coordinated regulation of nitrogen and phosphorus is critical for sustaining productivity and diversity in wetland plant communities.

Abstract Aims The stoichiometriy of plant leaves, twigs, and fine roots are key indicators for characterizing whole-plant adaptive strategies and for revealing the mechanisms underlying plant-environment interactions. Investigating the interrelationships among leaf-twig-root stoichiometriy in desert plants, as well as their differences in environmental adaptability, is essential for advancing our understanding of plant resource allocation strategies. Methods In this study, we selected 20 desert plant species from the Baijitan region of Ningxia and measured the concentrations of carbon (C), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) in the leaves, twigs, and fine roots of 77 individuals. Important findings (1) Leaf C concentrations were significantly lower than those in twigs and fine roots, whereas the N, P, K, Ca, and Mg concentrations of twigs and fine roots were significantly lower than those of leaves. (2) Network analysis showed that the overall network parameters—edge density, average path length, diameter, average clustering coefficient, and modularity—were 0.40, 1.75, 4, 0.59, and 0.11, respectively; a total of 54 element-element pairs exhibited significant correlations. (3) Leaf K concentration and twigs C concentration exhibited the highest degree and closeness centrality, identifying them as hub elements within the network. Twigs showed the highest element degree, indicating that they function as the key hub organ. (4) Variance partitioning revealed that soil pH, total C, and total P had the strongest effects on the stoichiometry of leaves, twigs, and fine roots, respectively; soil total N had the greatest influence on leaf and twigs N concentrations, whereas soil pH most strongly affected fine-root C concentration. This study systematically uncovers the element coordination network among leaves, twigs, and roots of desert plants in the Baijitan region and elucidates their response mechanisms to soil environmental factors, providing new theoretical support for understanding desert plant ecological adaptation from a multi-element perspective. Our findings further highlight the need to incorporate key elements such as K, Ca, and Mg when examining plant stoichiometry, in order to more comprehensively reveal the coordinated regulation of C, N, P, K, Ca, and Mg across different organs and their roles in environmental adaptation.