Aims Lianas are important components of tropical forest ecosystems, often restricting tree growth and biomass accumulation through their prevalence. Despite their ecological significance, the patterns of liana prevalence among forest trees and the factors influencing them remain poorly understood. This study examines how environmental condition and tree diameter infuence liana prevalence across three tropical forest types in Xishuangbanna, Southwestern China.

Methods Using the data from 21 1 hm² forest plots, this study assessed liana prevalence by comparing liana prevalence across forest types, analyzing environmental drivers, and exploring the trends in liana prevalence with increasing tree diameter at breast height (DBH).

Important findings Liana prevalence varied across forest types, with the highest rates observed in tropical seasonal moist forests (27.8% ± 9.2%), moderate rates in tropical rainforests (25.2% ± 10.6%), and the lowest rates in tropical lowland evergreen broadleaf forests (12.5% ± 10.7%). Key environmental factors influencing liana prevalence included Climate Principal Component 1, positivly loaded with temperature-related variables such as the minimum air temperature of the coldest month, the mean air temperature of the coldest quarter, and the mean air temperature of the driest quarter; Soil Principal Component 2, negatively loaded with nutrient factors like total carbon concentration, total nitrogen concentration, and hydrolyzable nitrogen concentration; and Soil Principal Component 3, primarily negatively loaded with total potassium concentration. Across all forest types, liana prevalence increased with tree diameter at breast height, indicating larger trees are more susceptible. Certain tree species exhibited pronounced liana prevalence in specific forest types. For example, Castanopsis indica exhibited liana prevalence of 54.3% in tropical rainforests and 40.6% in tropical lowland evergreen broadleaf forests, while Markhamia stipulata showed liana prevalence of 38.2% in tropical lowland evergreen broadleaf forests and 55.6% in tropical seasonal moist forests. Additionally, Mallotus barbatus and Mallotus philippensis recorded prevalence rates of 43.9% and 75.8% in tropical rainforests and tropical seasonal moist forests, respectively. This study highlights the variations in liana prevalence across environmental factors and tree diameter gradients in Xishuangbanna’s tropical forests. The findings advance our understanding of the interactions between liana prevalence, vegetation types, and environmental conditions, contributing to the sustainable management and conservation of tropical forests under 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 classification method, we analyzed the morphology, nutrient contents 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, 5.16, and 0.31 mg·g^-1, respectively) were lower than those in fine-roots of Chinese plants (473.9, 9.16, and 1.03 mg·g^-1, respectively). Among 1-3 order fine-roots, the coefficient of variation for carbon content was minimal (all are less than 1), while phosphorus content showed the largest coefficient of variation (94%). (2) The phosphorus content in fine-roots of 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) Principal component analysis 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. These findings 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.

Aims Global climate change is exacerbating the frequency of extreme drought events, underscoring the critical need to understand the resilience of trees and the factors influencing their recovery following these events.

Methods Seven dominant tree species in karst evergreen and deciduous broadleaf 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) With the exception of Cinnamomum camphora, all the studied tree species showed a percentage loss of xylem hydraulic conductivity (PLC) exceeding or approximating 50% at the end of extreme drought, with a maximum value of 87.92%. Across all the species, PLC demonstrated a linear decrease in relation to increasing xylem saturation water content at the end of extreme drought. Furthermore, PLC of porous species was significantly and positively correlated with xylem density (WD), but negatively with xylem saturation water content (SWC), indicating that xylem water storage capacity plays a crucial role in influencing the water transport function of karst trees under extreme drought conditions. (2) Following an extreme drought event, PLC in Fraxinus griffithii significantly increased in the subsequent spring. This suggests that the formation of new xylem vessels may be a critical mechanism for restoring water transport function in this species. In contrast, Choerospondias axillaris, Quercus acutissima, Quercus glauca, Boniodendron minius, and Machilus calcicola exhibited a significant increase in PLC within 3 and 13 days post-drought, respectively. For these species, the refilling of embolized xylem vessels appears to be the primary strategy for recovering water transport capacity. (3) Following an extreme drought event, the recovery degree of PLC in all tree species, measured over the final six sampling periods, exhibited a significant positive correlation with the mean saturated water vapor pressure deficit (VPD) within three days preceding each sampling, indicating the degree of atmospheric aridity significantly influenced the hydraulic function recovery of karst trees after soil moisture replenishment. (4) During the recovery process after extreme drought, most tree species showed embolism levels comparable to, or exceeding, those observed at the drought’s culmination. The ring-porous species demonstrated a greater degree embolism fatigue compared to diffuse-porous 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 In the present study, we leveraged eddy covariance flux data alongside concurrent meteorological data from the Positioning Observation and Research Station of Eucalyptus Plantation Ecosystem, spanning the years 2018 to 2022, to analyze 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. We analytically examined the relationship between WUE and various environmental 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 study period, the mean WUE of the Eucalyptus plantation ecosystem was recorded at 3.85 g C·kg^-1H₂O during the dry season (November to April) and 2.61 g C·kg^-1H₂O during the rainy season (May to October). The annual mean WUE was determined to be 3.22 g C·kg^-1H₂O. (2) WUE exhibited distinct diurnal variation patterns, with similar trends observed during both the dry and rainy seasons. A extremely significant negative correlation was identified between diurnal WUE and variables such as vapor pressure deficit (VPD), air temperature (T_air), soil temperature (T_soil), 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 T_soil, in addition to indirect negative influences from PAR. The responses of WUE to VPD and T_soil 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 variations 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, and the diurnal changes were mainly affected by VPD. In addition to being affected by VPD, the daily and monthly changes are also affected by light and temperature.

Aims The establishment of an ecological security pattern serves as a pivotal pathway and safeguard for sustainable development in semi-arid regions. Taking the Hunshandake Sandy Land as an example, this study aims to provide a novel approach to ecological protection and 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, targeting ecological core areas, restoration zones, and improvement regions.

Methods We focused on Hunshandake 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, used circuit theory, ecological corridors were identified and key ecological nodes were determined to establish the ecological security pattern within the Hunshandake Sandy Land, accompanied by the proposal of optimization recommendations.

Important findings The result indicated that: (1) The total area of the ecological source sites is 4 674.17 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 1 351.66 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 Hunshandake Sandy Land, consisting of “Ecological source sites-Water-Restoration areas”, have been completed.

Aims Nitrogen (N) addition can significantly affect the aboveground net primary productivity (ANPP) and belowground net primary productivity (BNPP) of grassland ecosystems. However, the mechanisms underlying 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 Eight N addition levels (0, 1, 2, 4, 8, 16, 24, 32 g·m^-2·a^-1) were set up in the Leymus secalinus grassland in Northern Shanxi, 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 levels. The saturation response thresholds of ANPP and NPP across five years (2017-2021) were 25.7 g·m^-2·a^-1and 21.3 g·m^-2·a^-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 aboveground increased as the level of N addition increased. (3) Nitrogen response efficiency of ANPP (NRE_ANPP)showed an exponential downward trend with the increase of N addition levels, while the nitrogen response efficiency of BNPP (NRE_BNPP) and nitrogen response efficiency of NPP (NRE_NPP) showed a linear downward trend with the increase of N addition levels. (4) Structural equation model analysis showed that soil NO^-₃-N content and pH regulated the effects of N addition and duration on plant ANPP and BNPP. There were 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 content indirectly regulated the response of ANPP and BNPP to N addition under high N addition treatments. This study indicates that plant productivity in grassland ecosystem responds nonlinearly with N addition levels, which provided dataset supporting for ecosystem service function of Leymus secalinus grassland in Northern Shanxi under the scenario 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 can provide a 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 Xizang, China. 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., Carex parvula, Carex alatauensis, and Potentilla saundersiana) maintained larger niche breadths, while narrow-niche species (e.g., Lagotis crassifolia and Phyllolobium milingense) 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 that positive associations increased and negative associations decreased 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.

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 investigated the interactive effects of litter cover and water depth 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 (wet, water-saturated, and flooded) and litter cover (0, 500, 1 000, and 1 500 g·m^-2) on the seed germination rates and emergence rates of Echinochloa crus-galli, E. crus-gallivar. mitis, Bidens pilosa, and Alisma plantago-aquatica.

Important findings We found that the seed germination rates and emergence rates of E. crus-galli, E. crus-gallivar. mitis and A. plantago-aquatica were significantly affected by litter cover, water depth, 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 100.0%, respectively. The germination rate of B. pilosa seeds beneath litter was significantly reduced by 94% compared to that above 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 germinated when covered by litter. However, only 1.5% to 17% of the seedlings penetrated through the litter layer. We posit that mechanical obstruction caused by litter cover is a critical factor influencing the seedling regeneration of A. plantago-aquatica. This study can help understand the distribution patterns and succession dynamics of wetland vegetation under environmental changes and has important implications for the ecological restoration and scientific management of wetland vegetation.

Aims Tree growth phenology is crucial for understanding forest carbon sequestration under global change. However, up until now, observational challenges have limited research on tree height growth, with most studies focusing on radial growth. Due to the scarcity of studies employing high-frequency monitoring, our understanding of the mechanisms driving tree growth phenology is limited. Additionally, canopy color indices are increasingly being used to study tree growth dynamics.

Methods We used area-array solid-state Lidar to continuously and at high frequency measure height growth dynamics of Cunninghamia lanceolata and Castanopsis carlesii saplings within a mesocosm experiment in subtropical china. We also derived RGB-converted canopy color indices from phenocams and integrated them with environmental factors data from a multi-factor meteorological observation system. The study aimed to explore the phenology of tree saplings height growth and its meteorological drives.

Important findings Our results indicated a synchronous start to the growing season for Castanopsis carlesii and Cunninghamia lanceolata, but a significantly earlier end for Castanopsis carlesii. Moreover, Cunninghamia lanceolata exhibited a significantly longer growing season and higher cumulative annual tree height growth than Castanopsis carlesii. The daily height growth rate of Castanopsis carlesii showed a significantly positive correlation with soil moisture. Conversely, the daily height growth rate of Cunninghamia lanceolatawas significantly negatively correlated with air temperature and soil moisture, but positively correlated with soil temperature and vapor pressure deficit (VPD). Notable differences in canopy color indices were identified between the two species: the daily height growth rate of Cunninghamia lanceolata was significantly positively correlated with the Green Excess Index (ExG), Green Chromatic Coordinate (Gcc), and Green Red Vegetation Index (GRVI), whereas Castanopsis carlesii correlated significantly with positively GRVI alone. In summary, this study utilized systematic phenological observation instruments to examine tree saplings height growth phenology and its driving factors. Furthermore, it utilized canopy color indices to retrieve tree height growth, offering key theoretical insights 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). Altitude does not have a significant effect on seedling emergence and mortality, whereas it significantly influences seedling growth performance. 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, few studies have explored the changing patterns and response mechanisms of NSC concentrations in different plant organs with time post fire.

Methods In the Huzhong area of the Da Hinggan Mountains, four severely burned plots at different burn times and one adjacent unburned plot were selected using the “space for time” method. The local dominant shrub species, Vaccinium vitis-idaea, was chosen, and the leaves and branches of different ages (current year and perennial), fine roots and rhizosphere soil samples were collected, further determining organ soluble sugar and starch concentrations, 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 remarkably. The starch concentration of current year branches was significantly higher than that of perennial branches from 2 to 10 years post fire. The NSC concentrations of branches and fine roots 18 years post fire differed substantially from those at unburned plot. In addition, leaf NSC concentration was negatively correlated with soil pH, leaf specific area and leaf nitrogen content. Furthermore, branch NSC concentration was positively correlated with time post fire and soil available phosphorus content, but negatively correlated with fine root nitrogen content. Fine root NSC concentration was positively correlated with time post fire while negatively correlated with fine root nitrogen content. In conclusion, the responses of V. vitis-idaea NSC concentrations to time post fire varied among organs, which is of great significance to 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 the content of plant defensive chemical compounds and their relationships with environmental factors such as altitude, soil pH, and moisture content was 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. 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 The wild resources of Fritillaria unibracteata, a precious and endangered medicinal plant, have been severely depleted due to long-term over-exploitation. To identify optimal cultivation practices and expand its planting range, this study aims to investigate the plant’s functional traits and the medicinal component content in its bulbs across different altitudes.

Methods A two-year field pot experiment was conducted along an altitudinal gradient from 3 410 m to 1 170 m, with five specific altitude levels. We monitored phenological phases, measured morphological traits, and analyzed the contents of total alkaloids and total saponins in the bulbs.

Important findings The results showed that the germination stage, leaf spreading stage and flowering stage of F. unibracteata were highly significantly advanced with decreasing altitude. In contrast, the wilting stage was first delayed and then advanced, resulting in a growing season length that initially increased and then decreased, peaking at (105.80 ± 4.87) d at 3 080 m. Plant height and single leaf area exhibited a unimodal pattern, first increasing and then decreasing with lower altitude, while the specific leaf area showed a “U”-shaped trend (first decreasing and then increasing). The individual bulb biomass also followed a unimodal pattern, reaching its maximum (1.40 ± 0.29) g at 3 080 m. The contents of total alkaloids and total saponins in bulbs demonstrated a “U”-shaped response to decreasing altitude. Notably, no significant difference was found in the total alkaloid at and above 2 370 m, with all values exceeding 0.07%. In conclusion, moderately lowering the cultivation altitude to the range of 2 370-3 080 m can extend the growing season, improve vegetative growth, and enhance bulb biomass accumulation without compromising key medicinal component content, thus representing a suitable and recommended range for the artificial cultivation of F. unibracteata.

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. 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. 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, moderate-xeric meadow, hygrophyte-mesophyte meadow, degraded semi-hygrophyte marshes, hygrophyte herbaceous marshes, hygrophyte peat bogs) in Dajiuhu wetland in Shennongjia as the study area. Six herbaceous plants, including Carex argyi, Rhynchospora chinensis, Scirpus karuisawensis, Eragrostis pilosa, Calamagrostis pseudophragmites, Agrostis clavata 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 argyiand Rhynchospora chinensis; (2) Eragrostis pilosa, Calamagrostis pseudophragmitesand Agrostis clavata 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 clavata 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.

Potaninia mongolica is an important constructive species and paleoendemic species in the Alxa desert, and it is a national secondary key protected plant species in China. Investigating the characteristics of the natural communities of Potaninia mongolia and its community classification can provide data support for the conservation and long-term monitoring of this species. In this study, 14 plots were investigated in eastern Alxa, and the quantitative characteristics of communities were studied by quadrat method. The results showed that: (1) A total of 48 plants species were recorded in the investigated communities, belonging to 39 genera of 14 families, dominated by Gramineae, Amaranthaceae, Compositae and Leguminosae. Annual or biennial herbaceous species were the dominant life form, accounting for 33.33% of the total species. Perennial herbs (25.00%), shrubs (20.83%) and semi-shrubs (20.83%) had similar proportions, but shrubs constituted the dominant layer of the community. Xerophytes are the primary water ecological type, accounting for 79.17% of the total species, of which strong xerophytes accounted for 35.42%, reflecting the climatic characteristics of intense aridity. Gobi species and gobi-Mongolia species dominate the floristic geographic elements, accounting for 29.16% and 22.92%, respectively, reflecting the floristic characteristics of desert vegetation. (2) According to the coexisting life forms and the degree of dominance, Potaninia mongolica desert in eastern Alxa was classified into four Association Groups: Potaninia mongolica - Herb Desert Association Group, Potaninia mongolica + Shrub - Herb Desert Association Group, Potaninia mongolica + Shrub Desert Association Group, Potaninia mongolica - Semi-shrub - Herb Desert Association Group, which were further divided into 13 Associations.