Forecasting potential water pollution areas (PWPA) is essential for effective watershed management. However, there remains a limited understanding of the spatial-temporal features that influence water quality (WQ), and advanced technical methods for WQ forecasting. This study developed an integrated framework utilizing spatial-temporal graph convolution networks (STGCN) to enhance comprehension of the spatial-temporal features influencing WQ and to develop a practical module for integrating features into the WQ prediction. The Pearson correlation method and seasonal decomposition analysis described the WQ features. Subsequently, the spatial-temporal distribution of PWPA was assessed using both the comprehensive pollution index method and Cressman space interpolation technique. Data from 403 monitoring stations was collected from the Yangtze River basin (YZR), encompassing pollutants such as COD, TP and NH₄⁺-N. The finding revealed that maximum concentrations of COD (36.4 mg/L), TP (4.078 mg/L) and NH₄⁺-N (13.58 mg/L) exceeded the standard thresholds necessitating early warnings. A significant correlation among pollutants was observed with coefficients ranging from 0.356 to 0.475 (P < 0.001), indicating their potential utility in predicting PWPA. Seasonality components exhibited strong correlations with the original WQ (correlation coefficients ranging from 0.62 to 0.89), followed by residuals (from 0.37 to 0.61) and trend components (from 0.25 to 0.53). The geographic layout of WQ monitoring stations along river lines resembled a graph network structure, suggesting that watershed WQ prediction can be classified as a spatial-temporal prediction task. The STGCN model achieved R2 values ranging from 0.607 to 0.844 for each pollutant on the test datasets, surpassing traditional models such as RNN, LSTM, and GRU in predictive accuracy. PWPA occurrences were predominantly identified in the southwestern regions as well as within the middle and lower reaches of the YZR. These results validated that the developed framework is capable of forecasting PWPA in large-scale watersheds while supporting effective watershed management.

Pollution sources release contaminants into water bodies via sewage outfalls (SOs). Using high-resolution images to interpret SOs is laborious and expensive because it needs specific knowledge and must be done by hand. Integrating unmanned aerial vehicles (UAVs) and deep learning technology could assist in constructing an automated effluent SOs detection tool by gaining specialized knowledge. Achieving this objective requires high-quality image datasets for model training and testing. However, there is no satisfactory dataset of SOs. This study presents a high-quality dataset named the images for sewage outfalls objective detection (iSOOD). The 10481 images in iSOOD were captured using UAVs and handheld cameras by individuals from the river basin in China. This study has carefully annotated these images to ensure accuracy and consistency. The iSOOD has undergone technical validation utilizing the YOLOv10 series objective detection model. Our study could provide high-quality SOs datasets for enhancing deep-learning models with UAVs to achieve efficient and intelligent river basin management.

Rebuilding a clear-water state dominated by submerged macrophytes is essential for addressing eutrophication, yet the impact of benthic fish on water quality is complex. We conducted two experiments to explore the interaction of submerged plants and benthic fish on the water quality. Experiment I investigated the water clearing effects of submerged macrophytes with varying coverage (from 0% to 40%) before and after the removal of benthic fish. Experiment II explored the impacts of benthic fish at different densities on aquatic ecosystems with and without submerged macrophytes. The results showed that an increase in submerged macrophytes coverage significantly enhanced the reduction of some major water quality parameters. We assert that the coverage of submerged macrophytes should not be lower than 40% to establish and sustain a clear-water state in shallow lakes. However, benthic fish significantly weaken the ability of submerged macrophytes to improve water quality. Surprisingly, the presence or absence of macrophytes may reverse the role of benthic fish in freshwater ecosystems. When macrophytes are present, benthic fish can cause water quality to deteriorate. Conversely, when macrophytes are absent, benthic fish with a density of ≤ 10 g/m3 can restrict the growth of phytoplankton by directly consuming algae or by disturbing sediments to increase turbidity, thereby potentially improving water quality. But the detrimental effects of benthic fish with higher densities may gradually outweigh their benefits to water clarity. Therefore, the percentage of submerged macrophyte cover in combination with the density of benthic fish play crucial roles in shaping the ecological effects of benthic fish and overall ecosystem dynamics. These findings underscore the importance of understanding ecosystem interactions and have practical implications for the management of shallow lakes.

Macrophytes with different growth forms exhibit diverse functional traits and ecological functions. In natural sub-deep lakes, there are often large differences in water quality between nearshore areas with macrophytes and open water areas. However, it remains unclear whether this phenomenon can be attributed to differences in plant growth forms. Therefore, we conducted continuous monitoring for four years, both before and after the implementation of an ecological restoration project, to explore whether the change in plant growth forms caused differences in water quality between the nearshore and open water areas. The results showed that implementing ecological restoration projects proved highly effective in improving the local environment, including water physicochemical properties and biological components, in the implementation area. First, the ecological restoration project greatly altered the plant community structure in the nearshore area before and after restoration. After restoration, there was a significant increase in the biomass and distribution area of noncanopy-forming plants (including erect and rosette-forming plants), while the opposite effect was observed for canopy-forming plants. Second, the transition of macrophyte community growth forms enhanced the stability of both macrophyte communities and water physicochemical parameters. Furthermore, the reduction in canopy-forming plants facilitated a more efficient water body exchange, resulting in greater homogeneity in water quality between the nearshore and open water areas. Overall, the presence of canopy-forming plants can hinder water body exchange due to large canopy formations on the water surface. In light of these findings, it is recommended that ecological restoration projects in natural lakes should consider the functional group composition of macrophytes.

Submerged macrophytes can improve water quality and buffer the effects of external nutrient loading, which helps to maintain a clear-water state in shallow lakes. We constructed 12 large enclosures with contrasting coverages (treatments) of submerged macrophytes (SMC) to elucidate their buffering capacity and resilience to nutrient pulses. We found that aquatic ecosystems with high SMC had higher buffering capacity and resilience, vice versa, i. e, the enclosures with high SMC quickly buffered the nutrient pulse and rebounded to clear-water state after a short stay in turbid-water state dominated by algae, while the treatments with low SMC could not fully buffer the pulse and rebound to clear-water state, and they slowly entered the transitional state after staying in turbid-water state. This means that the enclosures with high SMC had a better water quality than those with low SMC, i.e., the levels of nutrients and Chl-a were lower in the treatments with high plant coverage. In addition, plant coverage had a significantly positive buffering effect against nitrogen and phosphorus pulses, i.e., the nutrient concentrations in the treatments with high SMC took shorter time to return to the pre-pulse level. Overall, our results evidenced that the higher that the SMCs is, the better is the water quality and buffering capacity against nutrient pulses, i.e. the more stable is the clear-water state. However, low SMC may not be able to resist the impact of such strong nutrient pulse. Our results provide reference and guidance for water pollution control and water ecological restoration.

Introduction Macrophytes are essential for maintaining the health of shallow lake ecosystems, however, the driving and responsive relationship between ecological factors (such as seasonal changes and nutrition, etc.) and plant communities is not yet clear. Methods In this study, we conducted seasonal surveys of macrophyte community composition in lakes with different nutrient states, aiming to understand the incidence relation between macrophyte community diversity, seasonal changes and environmental factors. Results According to the classification criteria of comprehensive nutritional index, there were significant differences in the trophic status of the three lakes. Among them, the Xihu Lake has reached mild eutrophication with a TLI value of 56.33, both Cibi Lake and Haixihai Lake are mesotrophic with TLI value of 36.03 and 33.48, respectively. The results of diversity analysis showed a significant negative correlation between α-diversity (include Species richness, Shannon-Wiener index, Simpson index and Pielou index) and lake nutrient status. Among them, Xihu Lake showed the lowest α-diversity in all seasons, Haixihai Lake exhibited the middle α-diversity, Cibi Lake indicated the highest α-diversity. Non-metric multidimensional ordination showed that there were obvious spatial structures differences among the macrophyte communities in the three lakes. Macrophyte community composition in the three lakes was more similar in summer and autumn, but there was a wider gap in spring and winter. The redundancy analysis indicated distinct differences between diversity index and ecological factors, the eigenvalues of Axis 1 and Axis 2 being, respectively, 36.13% and 8.15%. Environmental factors could explain 44.8% of the total variation in macrophyte communities structure. Among these, nitrogen, phosphorus, water transparency and water temperature contributed 50.2%, 3.5%, 3.8% and 27.5%, respectively. Conclusions In summary, the community structure of macrophytes in plateau shallow lakes is co-regulated by seasons and nutrients.

Despite being one of the most abundant water resources globally, the Yangtze River Basin (YRB) region is facing substantial risks aggravated by climatic and anthropogenic changes. Here, we adopted an integrated framework to investigate the plausible futures of water resource provisioning in YRB under current and future conditions on the sub-watershed level: (i) a process-based model (InVEST) was used to project the water yield of the whole of YRB in the nearest future (2040–2060) and distant future (2080–2100) and (ii) a socio-ecological index was developed to assess the spatio-temporal patterns of water resources vulnerability (WRV). Model projections indicated that several water-rich areas in the southeastern YRB would suffer declining water yield in the future. While water yield was projected to increase in some drier regions in the northwest. Future changes in the basin-level vulnerability were projected to decrease under low emissions scenarios (RCP2.6) combined with a sustainability socioeconomic scenario (SSP1). The greatest increase in vulnerability was projected under the medium-to-high end (RCP7.0) rather than high-end (RCP8.5) climate change scenario. The areas with high WRV were distributed in sub-watersheds near Taihu Lake and the source of the Yangtze River. Climate and socioeconomic change were projected to have different roles in shaping the future dynamics of WRV, with precipitation reduction and water consumption increase being likely to result in increased WRV levels in the southeastern lower reaches and the middle reaches, respectively. Our study added new spatial data on projected water resource dynamics for the region of vital ecological and economic importance in Asia. The areas prone to increased WRV should be prioritised in future water resources management practices. The assessment approach used in this study integrated concurrent measures from both subjective and objective perspectives and could be used in relevant studies on exploring how future vulnerability could respond to environmental changes.

Aquatic plants in lakeshore zone play an important role in maintaining the health of lake ecosystem.In order to understand the current status of aquatic plants in the lakeshore zone of Lake Erhai,this study investigated the aquatic plants quarterly in the lakeshore zone from 2020 to 2021.The results showed that there were 206 species of aquatic plants belonging to 56 families and 156 genera in the lakeshore zone of Lake Erhai,including 149 species of hygrophytes,24 species of emergent plants,21 species of submerged plants,7 species of floating plants and 5 species of floating leaf plants.Among all these species,Cynodon dactylon,Zizania latifolia,Vallisneria natans and Trapa bispinosa,etc.were common species,Lonicera japonica,Elymus dahuricus,etc.were occasional species.From the distribution of floristic regions,the species in the lakeshore zone of Lake Erhai were mainly world distribution（83 species） and tropical distribution（55 species）,accounting for 40.28% and 26.71% of the total species,respectively.In terms of plant communities,there were 18 main plant community types in the lakeshore zone of Lake Erhai,including 4 types of hyophytes communities,3 types of emergent plant communities,9 types of submerged plant communities and 2 types of floating leaf plant communities.Among all the communities,the main dominant communities were Cynodon dactylon communities,Zizania latifolia communities,Vallisneria natans communities and Trapa bispinosa communities.Compared with previous investigations,it was concluded that the diversity of aquatic plants in the lakeshore zone of Lake Erhai had been significantly improved in recent years.However,there are some problems such as the small area of lakeshore zone and the single of emergent plant community.Therefore,the construction of lakeshore zone should be further strengthened to improve the habitats and increase species diversity.

Exploring the carbon sequestration capacity of water ecosystems would contribute to coping with climate change. This study conducted an integrated method framework to achieve an improved understanding of the relationship between carbon sequestration and lake ecosystem components, as well as provide a new perspective on climate change for pol-icymakers. The vertically generalized production model revealed the carbon sequestration capacity of lakes. The hier-archical linear model identified the cross-scale factors affecting phytoplankton. Then a developed multi-agents-based model with scenario analysis provided adaptive management strategies for carbon sequestration. Furthermore, we ap-plied the integrated framework in the 63 polluted lakes of Wuhan. The results showed that the average carbon seques-tration per unit area was at 0.87 kgC & BULL;m-2 & BULL;a-1, which was greater than that of the ocean and forest ecosystems, indicating that the lakes had a potential capacity for carbon sequestration. Total phosphorus had the strongest effect on the Chl-a (chlorophyll a) concentration (fixed effect (& gamma;) =6.82, P < 0.1), followed by total nitrogen (& gamma; = 6.38, P < 0.05), Rotifer biomass (& gamma; = 1.95, P < 0.01) and water temperature (& gamma; = 1.27, P < 0.05). These results indicated that the bottom-up effect of chemical factors on phytoplankton was greater than the top-down effect of zooplankton. The proportion of grassland at the whole-lakes level would have a negative synergistic impact on the Chl-a with chang-ing the micro water temperature at the part-lakes level (& gamma; = -46.64, P < 0.05). There was no significant interaction effect between land cover change and total nitrogen (phosphorus) on the Chl-a. Therefore, we could indirectly confirm that point source pollution emissions would synergistically affect the Chl-a and carbon sequestration along with the effects of physical-chemical conditions. The coordinated proportional control of nitrogen and phosphorus and the ar-tificial controlling biomass of zooplankton-feeding fish were proposed to improve carbon sequestration and water quality for lake management.

Urban community gardens (UCGs), greenspace cultivated and managed for vegetables by local communities, provide substantial ecosystem services (ES) and are warmly welcomed by residents. However, they also have many ecosystem disservices (EDS) and are almost always refused by the decision-makers of the government, especially in China. Better understanding the residents’ perceived ES and EDS and the impact on the behavioral intention (BI) toward UCGs is of great value to solve the conflicts between residents and the government concerning UCGs and to develop sustainable UCGs. Following the theory of planned behavior (TPB), we measured perceived ES/EDS, attitudes (ATT), perceived behavioral control (PBC), subjective norm (SN), and BI of 1142 residents in Changsha, China, and investigated their direct and indirect causal relationships using structural equation modeling (SEM). The results showed that: (1) ATT, PBC, and SN significantly and positively impact the BI of UCGs and together explained 54% of the variation of BI. (2) The extended TPB model with additional components of perceived ED/EDS improved the explanatory ability of the model, explaining 65% of the variance of BI. Perceived ES and perceived EDS showed significant direct positive and negative impacts on UCGs, respectively. They also indirectly impacted BI by influencing ATT, PBC, and SN. The findings of this study can extend our understanding of residents’ attitudes, behavior, and driving mechanism toward UCGs, and can help decision makers to design better policies for UCG planning and management.

Submerged plants are crucial for maintaining a clear water state in lakes, and their distribution area is usually determined by the lowest distribution boundary (LDB). However, LDBs of submerged macrophytes often exhibit species differences and vary with seasonal water level fluctuations. In this study, we carried out a three-year field investigation to compare differences in the LDBs of three submerged macrophyte species (i.e., Vallisneria natans, Ceratophyllum demersum, and Potamogeton maackianus) and explore their distinct determinants. We assumed that LDB differences would exist among the three species and that water level (WL) would be a key environmental driver of LDB dynamics, with an association between the LDBs of submerged macrophytes and water level fluctuations. Indeed, our results showed significant seasonal differences between C. demersum and V. natans in the period of September - May, with mean annual values in the order (low to high) V. natans, C. demersum, and P. maackianus. Furthermore, water level was a major driving force of the LDB dynamics of the three species. Changes in the LDBs of the three species in response to water level fluctuations could be divided into three periods: i.e., recovery growth period (April to June), stress tolerance period (July to September), and recession period (October to following March). This study not only clarifies the impact of water level on submerged macrophyte growth and distribution, but also has larger practical implications for the ecological restoration and management of large deep lakes.

Increasing eutrophication poses a considerable threat to freshwater ecosystems, which are closely associated with human well-being. As important functional entities for freshwater ecosystems, submerged macrophytes have suffered rapidly decline with eutrophication. However, it is unclear whether and how submerged macrophytes maintain their ecological functions under increasing eutrophication stress and the underlying patterns in the process. In the current study, we conducted an extensive survey of submerged macrophytes in 49 lakes and reservoirs (67% of them are eutrophic) on the Yunnan-Guizhou Plateau of southwestern China to reveal the relationship between submerged macrophyte biodiversity and ecosystem functioning (BEF) under eutrophication stress. Results showed that submerged macrophytes species richness, functional diversity (FD), and β diversity had positive effects on ecosystem functioning, even under eutrophication. Functional diversity was a stronger predictor of community biomass than species richness and β diversity, while species richness explained higher coverage variability than FD and β diversity. This suggests that species richness was a reliable indicator when valid functional traits cannot be collected in considering specific ecological process. With increasing eutrophication in water bodies, the mechanisms underlying biodiversity-ecosystem functioning evolved from “niche complementarity” to “selection effects”, as evidenced by decreased species turnover and increased nestedness. Furthermore, the relative growth rate, specific leaf area, and ramet size in trade-off of community functional composition became smaller along eutrophication while flowering duration and shoot height became longer. This study contributes to a better understanding of positive BEF in freshwater ecosystems, despite increasing anthropogenic impacts. Protecting the environment remained the effective way to protect biodiversity and corresponding ecological functions and services. It will be important to consider different facets of biodiversity on ecosystem functioning in future studies to improve effective management plans.

Evaluating water quality characteristics (WQC) and tracing pollutant sources (PS) have gradually attracted worldwide attention. This study was conducted to develop an integrated method framework for evaluating WQC, tracing PS, and improving understanding of their relationship to efficiently managing the water environment. The single-factor index, comprehensive water quality index (CWQI), and hazard quotient and hazard index (HQ and HI) were used to evaluate the characteristics of single pollutant concentration, comprehensive concentration, and human health risk, respectively. These evaluation methods combined with relevant standards selected data from the original sampling data. These selected data were used for tracing PS by principal component analysis and Pearson correlation methods. 3384 sampling data were collected in the Yellow River Basin in 2021, and the WQC assessment and pollutant traceability were carried out by using the above-integrated method framework. The results showed that TN(total nitrogen) was the primary pollutant with an average concentration of 4.54 mg/L, followed by CODcr(dichromate oxidizability), NH4+-N(ammonia nitrogen), and TP(total phosphorous). The CWQI values ranged from 1.26 to 110.03, with an average of 7.74, indicating the pollution level of trace elements was excellent. The HQ and HI max values of As(arsenic) and Cr6+(hexavalent chromium) elements were over 1, meaning the elements have negatively affected local human health. Furthermore, the anthropogenic input was the primary pollutant source for TN. The anthropogenic input and agricultural source pollution emission could be considered for CODcr, NH4+-N, TP, and BOD5(five-day biological oxygen demand). The anthropogenic input and the weathering and leaching of loess could be considered for As elements. For Cr6+, F(fluorine), Anionic, and Petroleum, the anthropogenic activities were the primary pollutant sources, including the metal mining and production and the coal mining and processing industry. Our results could provide effective information to support adaptive management measures to improve water environment conditions and protect human health.

Ecological environment conditions (EEC) assessment plays an important role in watershed management. However, due to insufficient field data, EEC assessment in large-scale watersheds faces challenges. Our study was conducted to develop an effective EEC assessment method framework that was capable of reducing the use of field data. Three indicators were developed from multisource data, including landscape ecological risk index (LERI), road network density (RND), and industry density (ID). The knowledge-based raster mapping approach integrated the three indicators into an overall score of the EEC. Then model validation was conducted with principal components of water quality from field sampling data by Pearson correlation analysis methods. Finally, we applied and demonstrated the constructed method framework in the EEC assessment of the YRB.The results showed that bad EEC (0.5326 < Overall score <= 0.7679) areas were mainly distributed in the northern part of the YRB, showing a circular distribution pattern. The areas with bad EEC were 15.84 million km(2), accounting for 19.87 % of the YRB. The area of the highest LERI (0.157 < LERI <= 0.246), the highest RND (4.4435 < RND <= 8.5574), and the highest ID (0.1403 < ID <= 0.2597) finally converted to bad EEC was 7.22 million km(2), 0.78 millionkm(2), and 0.91 million km(2), respectively. The results indicated that the ecological risk factors were the primary challenges for improving EEC, followed by industrial agglomeration and road network factors. The primary factors affecting EEC varied between the provinces in the YRB, suggesting that provinces take the management strategies and measures should be adaptive. The correlation coefficients between EEC and the principal components of water quality characteristics were between 0.022 and 0.241, P < 0.05. These findings validated that our method framework could distinguish the spatial variation of EEC in detail and further provide effective support for watershed management.

Abstract Analysis of stable isotope composition is an important tool in research on plant physiological ecology. However, large‐scale patterns of leaf‐stable isotopes for aquatic macrophytes have received considerably less attention. In this study, we examined the spatial pattern of stable isotopes of carbon (δ13C) and nitrogen (δ15N) of macrophytes leaves collected across the arid zone of northwestern China (approximately 2.4 × 106 km2) and attempted to illustrate its relationship with environmental factors (i.e., temperature, precipitation, potential evapotranspiration, sediment total carbon and nitrogen). Our results showed that the mean values of the leaf δ13C and δ15N in the macrophytes sampled from the arid zone were −24.49‰ and 6.82‰, respectively, which were far less depleted than those measured of terrestrial plants. The order of averaged leaf δ13C from different life forms was as follows: submerged > floating‐leaved > emergent. Additionally, our studies indicated that the values of foliar δ13C values of all the aquatic macrophytes were only negatively associated with precipitation, but the foliar δ15N values were mainly associated with temperature, precipitation, and potential evapotranspiration. Therefore, we speculated that water‐relation factors are the leaf δ13C determinant of macrophytes in the arid zone of northwestern China, and the main factors affecting leaf δ15N values are the complex combination of water and energy factors.

While planning and management of urban green space (UGS) remain primarily driven by policymakers and expert knowledge, increasing attention has been paid to the general public's perception of and demand for UGS. This study was conducted to provide price-related outcomes to support UGS-related decision making and achieve an improved understanding of the causal relationships underpinning the residents' willingness-to-pay (WTP) for UGS conservation. An extensive survey with 3000 urban residents from three provincial capital cities in central China (i.e., Wuhan, Changsha and Nanchang) was conducted. We applied structural equation modelling to examine a range of hypothetical causal relationships among residents' perceptions about ecosystem services/disservices provided by UGS, frequency of UGS visits, socioeconomic status (SES) and WTP for the conservation of five different types of UGS. We found that residents had an average WTP of 202.4 CNY or 30.6 USD per year cross UGS types, with the attached green space having the greatest WTP (223.0 CNY or 33.7 USD per year), followed by park (215.4 CNY or 32.6 USD year), square (201.7 CNY or 30.5 USD year), suburban ecological (190.1 CNY or 28.7 USD year) and protective (182.0 CNY or 27.5 USD year) green spaces. Perceptions of UGS's ecosystem services had a positive causal impact on WTP, while perceptions of ecosystem disservices would have a negative impact. The frequency of UGS visits was found to amplify WTP at a limited level. It could further heighten and diminish the perceptions of ecosystem services and disservices. Participants with higher SES typically had greater perceptions of UGS's ecosystem services and WTP. Finally, we found that the structure of the causal relationships on WTP varied between cities, highlighting the importance of considering the fine-level impacts of biophysical environment jointly. Our results could help urban planners to understand better the ways urban green space was perceived and anticipate the likely effects of changing spatial patterns of UGS on the benefits and nuisances experienced by the general public.

Understanding large-scale spatial patterns and determinants of biodiversity is a major challenge in macroecology and biogeography. Although some recent studies have focused on macrophyte richness patterns at local, regional and global extents, the majority of studied based on coarse resolution data, and few studies directly tested existing broad-scale hypotheses. Here, we conducted the extensive geobotanical surveys in the highly arid region of northwestern China, which covers 1/4 of the total area of China. Using collected species-level data, we examined macrophyte richness patterns along latitudinal and longitudinal gradients, and tested the mid-domain effect (MDE) and area effect (AE) hypotheses for the geographical patterns. Our study showed that the richness patterns of all macrophytes, emergent plants and submerged plants showed a hump-shaped pattern along latitudinal and longitudinal transects. Regression analyses showed that the MDE and AE can shape observed longitudinal and latitudinal richness patterns, and in comparison to the AE, the MDE has stronger effects. The summed explanations of MDE and AE for latitudinal and longitudinal richness patterns of all macrophytes, emergent and submerged plants were all over 93%, although the independent effects of the two tested hypotheses were weak (<22.8%). Our findings implied that the combined effects of MDE and AE structuring longitudinal and latitudinal patterns of macrophyte richness in this highly arid region may be due to extensive dispersal limitations such as desert and mountain ranges, highly isolated aquatic habitats, and abundant habitat types in the relatively larger regions.

Ecological stoichiometry is a powerful indicator for understanding the adaptation of plants to environment. However, understanding of stoichiometric characteristics of leaf carbon (C%), nitrogen (N%), and phosphorus (P%) for aquatic macrophytes remains limited. In this study, 707 samples from 146 sites were collected to study the variations in leaf C%, N%, and P%, and tried to explore how different environmental conditions affect leaf C, N, and P stoichiometry. Results showed that the mean values of leaf C%, N%, P%, and N:P ratios were 39.95%, 2.12%, 0.14%, and 16.60% of macrophytes across the arid zone of northwestern China, respectively. And the mean values of leaf P% were lower than those from the Tibetan Plateau and eastern China, which maybe due to an adaptation strategy of the plants to the unique conditions in the arid zone in the long-term evolutionary process. The higher N:P ratios suggested that P was established as the limiting factor of the macrophytes communities in the arid zone of northwestern China. There were significant differences in leaf C%, N%, P%, and their ratios among different life forms. Our results also showed strong relationships between leaf N% and N:P ratios and longitude, leaf N%, P%, and N:P ratios and latitude, and leaf N% and P% and altitude, respectively. In addition, the results showed that pH can significantly influence leaf C%. Our results supported the temperature-plant physiology hypothesis owing to a negative relationship between leaf N% and P% of macrophytes and mean annual temperature in the arid zone of northwestern China. The different patterns of leaf stoichiometry between the arid zone of northwestern China and eastern China indicated that there were different physiological and ecological adaptability of macrophytes to environmental gradients in different climatic zones.