Aims Lianas are a crucial component of tropical forest ecosystems. The prevalence of lianas can significantly restrict tree growth and biomass accumulation. However, the extent of liana prevalence among forest trees and the underlying factors contributing to this pattern remain insufficiently understood. This study investigates the effects of environmental factors and tree diameter variation on liana prevalence across different tropical forest types in Xishuangbanna. Methods The study utilized 21 one-hectare forest dynamic plots in Xishuangbanna to examine liana prevalence by analyzing the role of environmental factors associated with liana prevalence, conducting cross-comparisons of liana prevalence across tree diameter classes and forest types, and exploring the trend of liana prevalence with respect to tree diameter at breast height (DBH). Important findings The liana prevalence was highest in tropical seasonal moist forests (TSMF) (27.8% ± 9.2%), followed by tropical rainforests (TRF) (25.2% ± 10.6%), and lowest in tropical lowland evergreen broad-leaved forests (TLEBF) (12.5% ± 10.7%). The primary environmental factors influencing liana prevalence included Climate Principal Component 1, which had positive loadings for temperature-related variables such as the minimum temperature of the coldest month, the mean temperature of the coldest quarter, and the mean temperature of the driest quarter; Soil Principal Component 2, which was negatively associated with nutrient factors like total carbon concentration, total nitrogen concentration, and hydrolyzable nitrogen concentration; and Soil Principal Component 3, which was primarily loaded with total potassium concentration. In all forest types, liana prevalence increased with tree diameter at breast height (DBH). Castanopsis indica exhibited liana prevalence of 54.3% in TRF and 40.6% in TLEBF, while Markhamia stipulata showed liana prevalence of 38.2% in TLEBF and 55.6% in TSMF. Additionally, Mallotus barbatus and Mallotus philippensis exhibited liana prevalence of 43.9% and 75.8%, respectively, in TRF and TSMF. This study examined the variation patterns of liana prevalence in the tropical forests of Xishuangbanna in relation to environmental factors and tree diameter. It provided new scientific insights into the relationships among liana prevalence, vegetation types, and environmental factors in tropical forests, contributing to the sustainable management and conservation of these ecosystems in the context of global change.

Aims The root economic spectrum helps explore the trade-offs between resource acquisition strategies and lifespan of fine-roots of different orders, providing essential insights into the relationships among root traits and the mechanisms of species' adaptation under local environments. Methods This study investigates 30 shrub species with different life forms (evergreen and deciduous) suitable for the severely degraded karst region. Using the root order grading method, we analyzed the morphology, nutrients and stoichiometric ratios of 1-3 order fine-roots among different life forms. We aimed to understand the variations in morphology and nutrients across different root orders and explore the survival strategies and variation dimensions of fine-roots in different life forms, searching for the presence of a root economic spectrum. Important findings The results showed that (1) the average contents of carbon, nitrogen, and phosphorus in fine-roots of 30 karst shrubs (438.67 mg/g, 5.16 mg/g, and 0.31 mg/g, respectively) were lower than the average contents in fine-roots of Chinese plants (473.9 mg/g, 9.16 mg/g, 1.03 mg/g). Among 1-3 order fine-roots, the coefficient of variation for carbon content was minimal (1%), while phosphorus content showed the largest variation.(2) The phosphorus content in fine-roots of 30 evergreen shrubs was significantly lower than that of deciduous shrubs, indicating that evergreen shrubs in karst areas are more prone to phosphorus limitations compared to deciduous shrubs. (3) Root diameter and specific surface area showed a highly significant negative correlation only in the third-order fine-roots of deciduous shrubs, while evergreen shrubs exhibited significant negative correlations across 1-3 order fine roots. (4) PCA results indicate that variations in fine-root traits of 30 karst shrubs can be decomposed into multiple principal components. The first principal component mainly includes morphological traits such as specific root surface area, average diameter, specific root length, fine -root biomass, and root tissue density. The second principal component mainly reflects nutrient factors, corresponding to fast and slow resource acquisition strategies. This demonstrates the existence of a root economic spectrum among the 30 karst shrubs.The conclusions facilitate a deeper understanding of the ecological strategies of shrub adaptation to rocky desertification habitats in karst regions and further recognize the nutrient utilization strategies of suitable shrubs in these areas.

Abstract Aims With climate change, extreme drought events occur frequently around the world, and there is an urgent need to understand the resilience and influencing factors of trees after extreme drought. Methods Seven dominant tree species in karst evergreen and deciduous broad-leaved mixed forest in Guilin, Guangxi were selected to analyze the dynamic differences of xylem water transport function and its correlation with xylem characteristics and environmental factors at the end of extreme drought and after drought. Important findings (1) At the end of extreme drought, the percentage loss of xylem hydraulic conductivity (PLC) of all tree species except Cinnamomum camphora was higher than or close to 50%, and the highest was 87.92%.PLC of all species decreased linearly with the increase of xylem saturation water content at the end of extreme drought. PLC of porous species had significant positive and negative correlations with xylem density (WD) and xylem saturation water content (SWC), respectively, indicating that xylem water storage capacity was an important factor affecting water transport function of karst trees under extreme drought. (2) PLC of Fraxinus chinensis decreased significantly for the first time in the spring of the following year after extreme drought, and the formation of new vessels may be the strategy for restoring water transport function after extreme drought. The PLC of Choerospondias axillaris and Quercus acutissima, Quercus glauca, Boniodendron minius and Machilus calcicola decreased significantly for the first time on the 3rd and 13th day after extreme drought, respectively. The refilling of embolized vessels may be the strategy to restore water transport function of these species. (3) After the extreme drought event, the PLC recovery degree of all tree species at the last 6 sampling times was significantly positively correlated with the mean saturated water vapor pressure deficit (VPD) within 3 days before the current sampling time, indicating that the degree of air dryness had an important effect on the hydraulic function recovery of karst trees after extreme drought after the soil moisture condition recovered. (4) During the recovery process after extreme drought, many tree species showed embolism degree close to or even higher than that at the end of extreme drought, and the embolism fatigue degree of annular porous wood species was higher than that of loose porous wood species.

Aims Examining how water use efficiency (WUE) in plantations responds to environmental factors is crucial for understanding vegetation's water strategies and assessing ecosystems' carbon and water recycling capacity. Methods Utilizing eddy covariance flux data alongside concurrent meteorological data from the National Posi-tioning Observation and Research Station of Eucalypt Plantation Ecosystem, spanning the years 2018 to 2022, this study conducted an analysis of the temporal variations and seasonal differences in WUE within the Eucalyptus plantation ecosystem. The analytical methods employed included stepwise regression analysis, path analysis, and redundancy analysis. An investigation was conducted to examine the relationship between WUE and various envi-ronmental factors, with a particular focus on the distinctions between drought and rainy seasons, as well as the primary factors influencing these variations. Important findings (1) Throughout the observation period, the mean WUE of the Eucalyptus plantation ecosystem was recorded at 3.85 g C·kg–1 H2O during the dry season (November to April) and 2.61 g C·kg–1 H2O during the rainy season (May to October). The annual mean WUE was determined to be 3.22 g C·kg–1 H2O. (2) WUE exhibited distinct diurnal variation patterns, with similar trends observed during both the dry and rainy seasons. A significant negative correlation was identified between diurnal WUE and variables such as vapor pressure deficit (VPD), air temperature (Tair), soil temperature (Tsoil), photosynthetically active radiation (PAR), and soil moisture (SM). Furthermore, stepwise regression analysis indicated that VPD serves as the primary environmental factor influencing the diurnal variation of WUE. (3) The temporal variation of daily scale WUE exhibited an inverse relationship with gross primary productivity (GPP) and evapotranspiration (ET). Path analysis indicated that WUE is predominantly influenced by direct negative impacts from VPD and Tsoil, in addition to indirect negative influences from PAR. The responses of WUE to VPD and Tsoil demonstrated significant discrepancies between dry and rainy seasons, while the seasonal responses to PAR were found to be consistent. (4) On a monthly basis, WUE was predominantly influenced by temperature and VPD during the dry season, while PAR played a significant role in the rainy season. The vari-ations in WUE across different seasons were primarily influenced by alterations in ET, which were governed by temperature, VPD, and PAR. The WUE of the Eucalyptus plantation ecosystem exhibited marked variations between the drought and rainy seasons, with the primary controlling factors differing according to the temporal scale.

Aims： The establishment of an ecological security pattern serves as a pivotal pathway and safeguard for sustainable development in semi-arid regions. Taking the Hunshandak Sandy Land as the research subject, this study aims to provide a novel approach to ecological protection and the construction of an ecological security pattern in semi-arid regions, which integrates "Ecosystem Services (ES), landscape morphology, machine learning, and circuit theory." Additionally, we propose optimized environmental management strategies centered on the sustainable utilization of water and ecology, targeting ecological core areas, restoration zones, and improvement regions. Methods： We focused on Hunshandak Sandy Land and employed the "Ecological Source-Resistance Surface-Ecological Corridor" paradigm to assess six ecosystem services, including livestock production, carbon sequestration, water yield, soil conservation, sandstorm prevention, and habitat quality. By integrating Morphological Spatial Pattern Analysis (MSPA), we identified core areas and water bodies as ecological source areas and employed a random forest model and spatial operations to generate the resistance surface. Furthermore, we used circuit theory, ecological corridors were identified and key ecological nodes were determined to establish the ecological security pattern within the Hunshandak Sandy Land, accompanied by the proposal of optimization recommendations. Important findings： The results indicated that:(1) The total area of the ecological source sites is 4674.17 km2, accounting for 14.96% of the total area, primarily concentrated in the eastern region. Ecological source sites in the central region are fragmented. (2) We identified 51 ecological corridors with a total length of 1351.66 km; there are 57 ecological nodes, mainly distributed in the central-southern and narrow corridors in the north. (3) The construction and optimization of the ecological security pattern from east to west in the Hunshandak Sandy Land, consisting of "Ecological source sites - Water - Restoration areas", have been completed.

Aims Nitrogen (N) addition significantly affected the aboveground net primary productivity (ANPP) and belowground net primary productivity (BNPP) of grassland ecosystems. However, the different responses of plant ANPP and BNPP to N addition and their saturation response thresholds at different levels of N addition are not clear. Methods Therefore, eight N addition levels (0, 1, 2, 4, 8, 16, 24, 32 g N m-2 year-1) were set up in the Leymus secalinus grassland in northern Shanxi Province, and the changes of plant ANPP, BNPP and total net primary productivity (NPP) were monitored for five years from 2017 to 2021. The temporal stability, N saturation threshold and N response efficiency of plant productivity were also calculated. Important findings The results showed that: (1) ANPP and NPP were increased nonlinearly with the increase of N addition level. The saturation response thresholds of ANPP and NPP across five years (2017-2021) were 25.7 g N m-2year-1 and 21.3 g N m-2year-1, respectively. (2) ANPP and BNPP had different sensitivities to N addition, and the sensitivity of ANPP was higher than that of BNPP. The change in NPP was mainly caused by changes in ANPP, suggesting that plant productivity distribution to the ground increased as the level of N addition increased. (3) NREANPP showed an exponential downward trend with the increase of N addition levels, while the NREBNPP and NRENPP showed a linear downward trend with the increase of N addition level. (4) Structural equation model analysis showed that soil NO3--N and pH regulated the effects of N addition and years on plant ANPP and BNPP. There was different regulatory mechanisms of ANPP and BNPP under low N and high N addition treatments. Both ANPP and BNPP were directly affected by N addition under low N addition treatments, while the soil inorganic N indirectly regulated the response of ANPP and BNPP to N addition under high N addition treatments. This study showed that plant productivity in grassland ecosystem responded nonlinearly with N addition level, which provided data support for improving the ecosystem service function of Leymus secalinus grassland in northern Shanxi Province under the background of N deposition.

Aims To investigate the effects of plateau pika (Ochotona curzoniae) disturbance on niche breadth, niche overlap, ecological response rate, and interspecific associations of dominant plant species in alpine meadows, and to provide the scientific basis for the conservation and management of alpine meadow ecosystems. Methods From July to August 2020, disturbed and undisturbed plots were established across six typical alpine meadow regions located in the south-central part of the Tibet Autonomous Region. Plant species composition, individual abundance, and distribution were recorded through field surveys and quadrat sampling methods. Levins' formula was applied to calculate species niche breadth. Pianka's index was used to determine niche overlap, while ecological response rates were computed to assess resource competition dynamics among species. Additionally, the variance ratio method combined with 2×2 contingency table chi-square tests was employed to analyze interspecific associations. Important findings The disturbance caused by plateau pikas significantly influenced the niche characteristics and interspecific associations of dominant plant species. Under disturbance conditions, broad-niche species (e.g., Kobresia pygmaea, Kobresia humilis, and Potentilla saundersiana) maintained larger niche breadths, while narrow-niche species (e.g., Lagotis crassifolia and Astragalus milingensis) exhibited significantly reduced niche breadths. Overall niche overlap values decreased under disturbance, indicating reduced competitive pressures among species. Analysis of ecological response rates revealed that species generally exhibited negative feedback mechanisms under disturbance conditions, which contributed to community stability. In contrast, positive feedback mechanisms dominated in undisturbed conditions, potentially leading to excessive expansion of certain species. Interspecific association analysis demonstrated increased positive associations and decreased negative associations under disturbance conditions, facilitating synergistic interactions and coexistence among species. Plateau pika disturbance can alter the structure and function of alpine meadow plant communities by influencing plant niche characteristics and interspecific associations, thereby promoting resource differentiation and niche differentiation among species while reducing competition intensity within the community. Therefore, moderate plateau pika disturbance may be beneficial for enhancing community stability and species diversity. In the conservation and management of alpine meadow ecosystems, it is recommended to comprehensively consider the ecological role of plateau pikas and formulate rational management strategies accordingly.

Abstract Aims Water depth is a critical environmental factor in wetland ecosystems, influencing plant growth, regeneration, and distribution patterns. As an essential component of natural ecosystems, litter affects the regeneration of plant seedlings through various mechanisms such as light attenuation, mechanical obstruction, and allelopathy.Wetland ecosystems tend to accumulate a larger amount of litter because of flooding and anaerobic conditions. However, few studies have paid attention to the interactive effects of litter cover and water depth changes on the regeneration of plant seedlings. Methods This research simulated the field environmental conditions in mobile rain shelters to analyze the influences of water depth variation (wet, water-saturated, and flooded) and litter cover(0, 500, 1000, and 1500 g/m2) on the seed germination rates and emergence rates of Echinochloa crus-galli, E. crus-galli var. mitis, Bidens pilosa, and Alisma plantago-aquatica. Important findings The results demonstrated that the seed germination rates and emergence rates of E. crus-galli, E. crus-galli var. mitis and A. plantago-aquatica were significantly affected by litter cover, moisture conditions, and their interactions, while B. pilosa was only significantly influenced by litter cover. Litter cover decreased the germination and emergence rates of B. pilosa by 59.4% to 96.9% and 94.4% to 100% respectively. The germination rate of B. pilosa seeds beneath the litter was significantly reduced by 94% compared to that above the litter, indicating that the shading effect resulting from litter cover was the primary cause restricting the germination of B. pilosa seeds. The germination rate of A. plantago-aquatica seeds was nearly zero under wet conditions, but increased to over 30% in water-saturated or flooded environments, suggesting that sufficient moisture is of vital importance for the germination of A. plantago-aquatica seeds. Under water-saturated or flooded conditions, 29% to 60% of the seeds of A. plantago-aquatica can germinate when covered by litter. However, only 1.5% to 17% of the seedlings can penetrate through the litter layer. It was supposed that the mechanical obstruction caused by the litter cover is the crucial factor influencing the seedling regeneration of A. plantago-aquatica.This study provides fundamental data for revealing the distribution patterns and succession dynamics of wetland vegetation under environmental changes and holds significant importance for the ecological restoration and scientific management of wetland vegetation. Key words Litter; Water depth; Wetland ecosystem; Seedling germination

Aims The phenology of tree growth is a key research priority in the field of forest carbon sequestration within the context of global change. However, up until now, due to challenges in observation, the majority of studies have focused on the radial growth dynamics of trees, and the study of height growth patterns still lacks comprehensive coverage. Additionally, few studies employ high-frequency monitoring techniques, which limited utilization of high-frequency measurements hinders our understanding of the underlying phenological drivers. The use of canopy color indices to infer tree growth dynamics is also becoming a trend. Methods Here, we have employed area array solid-state lidar for continuous, high frequency measurements of saplings Cunninghamia lanceolata and Castanopsis carlesii height growth dynamics in a experimental mesocosm. Furthermore, we acquired RGB-converted canopy color indices from visible time-lapse photographs and integrated them with environmental factors monitored via a multi-meteorological factors observation system. The objective was to investigate the phenology of saplings height growth and their climate drives. Important findings The results indicated that the growing seasons of Castanopsis carlesii and Cunninghamia lanceolata started at similar times, but the growing season of Castanopsis carlesii ended significantly earlier than that of Cunninghamia lanceolata. Additionally, Cunninghamia lanceolata had a significantly longer growing season and a greater cumulative annual growth in tree height compared to Castanopsis carlesii. The daily growth rate of Castanopsis carlesii was significantly positively correlated with soil moisture content. In contrast, the daily growth rate of Cunninghamia lanceolata was significantly negatively correlated with air temperature and soil water content, while showing a significant positive correlation with soil temperature and vapor pressure deficit (VPD). Notable differences in canopy color indices were observed between the two species: the daily growth rate of Cunninghamia lanceolata were significantly positively correlated with the Green Excess Index (ExG), Green Chromatic Coordinate (Gcc), and Green Red Vegetation Index (GRVI), while Castanopsis carlesii showed significant correlation with GRVI only. In summary, this study employed systematic phenological observation instruments to analyze the height growth phenology and its influencing factors in trees. Additionally, it utilized canopy color indices to infer tree growth, providing important theoretical evidence for forest carbon sequestration research.

Aims As representative ecosystem engineers in alpine subnival ecosystems, cushion plants play a crucial role in maintaining the structure and diversity of plant communities in these regions. Therefore, The dynamic changes (e.g., population decline) in cushion plant populations way directly affect the long-term maintenance of ecosystem functions in alpine subnival zones. However, how the key stages in the dynamics of cushion plant populations—specifically seed emergence and seedling growth—respond to environmental factors is underexplored. Methods This study investigated the effects of different temperatures and seed burial depths on seed emergence rates and seedling growth of the alpine cushion plant Arenaria oreophila, using seeds collected from multiple natural populations under controlled laboratory incubation. Important findings The results indicate that higher temperatures (above 10 °C) accelerate seed germination and seedling emergence, thereby increasing over seedling emergence rates. However, seed burial depth limits seedling emergence rates; when burial depth exceeds 2 cm, seedling emergence rates significantly decrease, or seeds even fail to emerge, regardless of temperature conditions. Low temperatures (below 5 °C) severely inhibit seed emergence and seedling growth. Seedlings grown at higher temperatures exhibit significantly greater heights and biomass accumulation efficiency, with higher fresh and dry weights compared to those grown at lower temperatures. An optimal burial depth of 1 cm further supports biomass accumulation. However, excessively high temperatures pose a significant risk of seedling mortality. We suggest that excessively high temperatures (above 20 °C) and deep burial depths (greater than 2 cm) are detrimental to seedling emergence and growth of Arenaria oreophila. Optimal conditions for seedling emergence and growth are moderate temperatures (10-15 °C) and shallower burial depths (less than 1 cm). Additionally, there may be population-level differences in environmental adaptability among seeds from different populations. This study further suggests that under global climate warming, the field populations of cushion A. oreophila may face numerous uncertain risks: the large, loose-grained soil substrate of subnival zones makes seeds susceptible to becoming buried too deeply, complicating subsequent seedling emergence, and while increased temperatures (due to climate warming) may promote seedling growth, they also substantially increase seedling mortality risk. Both of these two processes may inhibit the potential regeneration process of the populations of cushion A. oreophila.

Aims In recent years, fires triggered by extreme weather have caused severe damage to forest ecosystems, leading to a sharp increase in tree mortality. Non-structural carbohydrates (NSC) can reflect the response of plants to post-fire environmental changes and their adaptive strategies. However, there are currently few studies on the changing patterns and response mechanisms of NSC concentrations in different plant organs with time since fire. Methods In the Huzhong area of the Da Hinggan Mountains, four severely burned plots with different burn times and one adjacent unburned plot were selected using the "space instead of time" method. The local dominant shrub species, Vaccinium vitis-idaea, was used as the research object, and the leaves and branches of different ages (current year and perennial), fine roots and rhizosphere soil samples were collected to determine the soluble sugar and starch concentrations of each organ, functional traits of leaves and fine roots, and the soil properties. Important findings The order of NSC concentrations in different organs of V. vitis-idaea was leaves > branches > fine roots. The soluble sugar concentration of current year leaves increased significantly after fire, whereas the starch concentration of perennial leaves increased significantly. The starch concentration of the current year branches was significantly higher than that of perennial branches from 2 to 10 years after fire. The NSC concentrations of branches and fine roots 18 years after fire were still significantly different from those without fire. In addition, leaf NSC concentration was negatively correlated with soil pH, leaf specific area and leaf nitrogen content; branch NSC concentration was positively correlated with time since fire and soil available phosphorus content, and negatively correlated with fine root nitrogen content; fine root NSC concentration was positively correlated with time since fire and negatively correlated with fine root nitrogen content. In conclusion, the response of V. vitis-idaea leaf-branch-fine root NSC concentrations to time since fire showed significant organ variability, which is of great significance for accurately understanding the physiological and ecological changes of plants during post fire recovery.

Aims With the intensification of climate change, shrub expansion or encroachment in high-altitudes and high-latitude has become increasingly significant. However, the patterns and driving mechanisms of changes in plant defensive chemicals such as total phenols and condensed tannins during such shrub expansion processes in alpine regions remain poorly understood. Methods Taking the alpine shrub-meadow transition zone or ecotone in western Sichuan on the eastern Qingzang Plateau as the study area, sample plots were established along a shrub expansion gradient including control (0% coverage), light expansion (<30% coverage), light-moderate expansion (30%–45% coverage), moderate-heavy expansion (45%–60% coverage), and heavy expansion (>60% coverage). The impact of shrub expansion on plant defensive chemical compounds and their relationships with environmental factors such as elevation, soil pH, and moisture content were analyzed by a space-for-time substitution approach. Important findings The results showed that: (1) Shrub expansion significantly increased the density, height, volume, and weighted density of shrubs in the alpine shrub-meadow transition zone of western Sichuan; (2) Compared to herbaceous plants and Sorbus rufopilosa, Rhododendron lapponicum exhibited higher levels of phenolic compounds during the shrub expansion process; (3) Changes in species composition at the community level had a significantly greater impact on the variation in plant phenolic compounds than intraspecific variation resulting from phenotypic plasticity among individuals; (4) Concentrations of phenolic compounds in both plant leaves and roots showed significant correlations with their carbon to nitrogen ratios, while soil factors had a relatively minimal effect, supporting the Carbon-nutrient Balance Hypothesis (CNBH). In summary, this study sheds light on the positive impact of shrub expansion on plant defense compounds and provides critically theoretical underpinnings for ecosystem management and plant conservation in the context of global change.

Aims Fritillaria unibracteata is a precious and endangered medicinal plant. Due to long-term excessive bulbs exploitation, its wild plant resources have been gradually decreasing. This study was aim to explore the growth status of F. unibracteata and the content characteristics of medicinal components in bulbs at different altitudes, especially at low altitudes. it was contribute to expand artificial planting areas of F. unibracteata, and alleviate the severe contradiction between supply and demand in the market. Methods This study carried out a two-year field pot experiment of F. unibracteata at five altitudes from low altitude (1170 m) to high altitude (3410 m). We measured phenological index and morphological characteristics of F. unibracteata, and the contents of total alkaloids and total saponins in burbs. Important findings The results indicated that the germination stage, leaf spreading stage and flowering stage of F. unibracteata were highly significantly advanced with the decreased altitude (P<0.01), while the wilting period was delayed first and then advanced with the decreased altitude. The length of growing season increased first and then decreased with the decreased altitude, and the longest value was (105.80 ± 4.87) days at 3080 m above sea level (asl). The plant height and single leaf area increased first and then decreased with the decreased altitude, while the specific leaf area decreased first and then increased. The individual bulb biomass increased first and then decreased with the decreased altitude, and the maximum value was (1.40 ± 0.29) g at 3080 m asl. The contents of total alkaloids and total saponins in bulbs decreased first and then increased with the decreased altitude. There was no significant difference in the content of total alkaloids in bulbs above 2370 m asl (P>0.05), and the contents were all higher than 0.70 mg/g. This study found that appropriately reducing the planting altitude of F. unibracteata was helpful to prolong the growth season, increase plant height and leaf area, and promote the accumulation of bulb biomass. The results suggested that considering the differences of bulb biomass and medicinal component content of F. unibracteata at different altitudes, its suitable planting range at low altitude could be selected from 2370 m to 3080 m asl.

Aims As a crucial organ for plants to conduct matter and energy exchange with the external environment, the leaf's anatomical structure changes can directly reflect the adaptation strategies of plants to diverse habitats. This study aims to conduct research on the dominant plants in different habitats of Dajiuhu wetland, Mt. Shennongjia, and investigate the adaptive response of plant leaf anatomical structure traits to habitats with different water levels. Methods We selected six different habitats (xeric meadow (HA), moderate- xeric meadow (HB), hygrophyte- mesophyte meadow (Z), degraded semi-hygrophyte marshes (SA), hygrophyte herbaceous marshes (SB), hygrophyte peat bogs (SC)) in Dajiuhu wetland in Shennongjia as the study area. Six herbaceous plants, including Carex argyi, Rhynchospora chinensis, Scirpus karuisawensis, Eragrostis pilosa, Calamagrostis pseudophragmites, Agrostis matsumurae were collected from the Dajiuhu wetland and the leaf anatomy of these species were studied by using paraffin sectioning method. Important findings The results showed that: (1) the adaptation structures of different plants to the changes in habitat water level differed. Carex argyi, Rhynchospora chinensis and Scirpus karuisawensis grew in swampy habitats with good water conditions. When the water level increased, the air cavity, vascular bundle and upper and lower epidermal cell cross-section significantly increased. The leaf thickness and xylem diameter in vascular bundles increased significantly in Carex argyi and Rhynchospora chinensis; (2) Eragrostis pilosa, Calamagrostis pseudophragmites and Agrostis matsumurae were distributed in drier dry and mesic meadows, and most structures in leaf transection did not show significant differences between habitats. Only the width and thickness of bulliform cells and upper epidermal cell thickness of Eragrostis pilosa, along with the lower epidermal cell thickness of Calamagrostis pseudophragmites, increased when the habitat water level decreased. Eragrostis pilosa and Agrostis matsumurae are C4 plants with trichomes or protuberances on the leaf surface, which may be related to the drought resistance. The developed aerenchyma and conducting tissues of Carex argyi, Rhynchospora chinensis and Scirpus karuisawensis ensured the flow of gas and water. The study of the anatomical structure traits of plant leaves in different habitats reflects the strategies of the wetland plants to cope with the changes in ground water level. It can provide a reference for exploring the adaptation of plants to environmental water changes.