The "International Wetland City" certification proposed by the Ramsar Convention is a new initiative to promote wetland protection and restoration. Taking Changde City, an International Wetland City, as an example, based on the refined classification data of wetlands from 2000 to 2022, this study monitored the changes in wetland protection and restoration, quantitatively analyzed the importance and contribution rate of the driving factors for every single refined wetland types, and finally explored the spatial distribution pattern of the dominant driving factors. The results showed that: (1) During 2000-2022, the effectiveness of wetland protection and restoration in Changde City was significant, increasing from 1298.53 km(2) to 1399.61 km2. (2) Wetland stability was the main type of wetland change (61.86%), followed by wetland restoration (22.10%) and wetland damage (16.04%). (3) Attribution analysis found that wetland restoration was mainly attributed to the return of farmland to wetland, while wetland damage was mainly caused by climate dryness; mudflats, grassland, and reed wetlands, pits, and rivers were mainly affected by arable land while lakes by construction land; reservoirs and canals were affected by rainfall. (4) In terms of attribution zoning, agricultural activities drove 68.76% of wetland changes, urbanization and climate change contributed 22.03% and 9.21% respectively.

The"international wetland city"certification proposed by the Ramsar convention is a new measure to promote wetland conservation and restoration.Taking the international wet-land city of Changde as an example,based on the 15-meter spatial resolution wetland classifica-tion data from 2000 to 2022,we monitored the dynamic changes of wetland protection and res-toration in Changde city year by year,quantitatively analyzed the importance and contribution rate of wetland protection and restoration driving factors,and finally explored the spatial distri-bution pattern of dominant driving factors.The results show that:(1)During 2000-2022,the wetland protection and restoration in Changde city achieved significant results,increasing from 1298.53 km2 to 1399.61 km2.The establishment of wetland reserves has a positive impact on wetland protection and restoration.(2)The main types of wetland changes are wetland stability(61.86％),followed by wetland restoration(22.10％)and wetland loss(16.04％).(3)Attribution analysis reveals that wetland restoration is mainly attributed to returning farmland to wetlands,and wetland damage is mainly caused by climate drought;mud flats,grass flats,reed wetlands,ponds,and rivers are mainly affected by arable land;lakes are mainly affected by construction land;and reservoirs and canals/canals are mainly affected by rainfall.(4)In the attribution parti-tion,agricultural activities contribute to 68.76％of wetland changes,while urbanization and cli-mate change contribute to 22.03％and 9.21％,respectively.

Accurate and reliable mangrove datasets are essential for the protection and management of mangrove ecosystems. Therefore, the evaluation of the current mangrove datasets and understanding the differences among them are critical. This study takes the Guangxi Beibu Gulf (GBG) and Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as the study areas and analyzes the agreement and accuracy of eight mangrove datasets from 2000 to 2020 using area comparison, spatial agreement analysis, and absolute accuracy evaluation. The results show that; 1) significant differences exist in mangrove area and spatial distribution among the different mangrove datasets, with the percentage of high agreement areas ranging from 10% to 42%. 2) The overall accuracy of the evaluated mangrove datasets ranges from 56.2% to 95.6%, and the classification accuracy of mangrove datasets in inland areas is lower than the overall level. 3) There are regional differences in the quality of mangrove datasets, with the agreement and accuracy of mangrove datasets in the GBG being greater than those in the GBA. 4) Fine-scale mangrove mapping based on high-resolution remote sensing images, such as Sentinel, and global mangrove mapping based on the Google Earth Engine (GEE) cloud platform should be emphasized in the future. The findings of this study can provide guidance for data users to select appropriate mangrove datasets and a reference for future mangrove mapping research.

Wetlands are important natural resources for humans and play an irreplaceable ecological function in the terrestrial ecosystem. To curb the continued loss of wetlands globally, international organizations and many countries have taken a series of major conservation and restoration measures. This work reviews these wetland conservation and restoration measures, interprets China’s wetland conservation and restoration management policies, and proposes that future research on wetland resources in China should be conducted from the aspects of international frontiers and national strategic plans, socioeconomics, and smart services. The results show that the 27 International Wetlands Days from 1997 to 2023 provided new goals and tasks for the protection and management of wetlands. The important topics and outcomes of the 14 Conferences of the Contracting Parties to the Convention on Wetlands from 1980 to 2022 provided new directions and new challenges for wetland development. In the future, we should enhance wetland ecological functions, promote sustainable wetland development, and overcome the technical bottleneck of fragile wetland ecosystem restoration. From 1992 to 2022, China embarked on a new phase of wetland protection and restoration. The overall experience of wetland protection and restoration in China has been formed through national strategic deployment, legal policy establishment, and project planning and implementation. The needs to provide for and plan the long-term protection of wetlands at the national level, to innovate restoration and management techniques and application systems, and to effectively address the complex issues of wetland protection and restoration through collaborative division of labor among multiple departments were emphasized. Research on the future trends of wetlands should be directed towards the exploration and practice of the United Nations Sustainable Development Goals and several international conventions in support of sustainable wetland development. Wetland protection, restoration, and management services should be promoted for national strategic needs and local, high-quality social and economic development. In addition, research on cross-integration and academic innovation should be enhanced for disciplinary development, global supervision, comprehensive assessment, and smart decision making.

Food supplementation has become an increasingly prevalent strategy for animal conservation. A large white-tailed eagle (Haliaeetus albicilla) population exists in a wetland in Northeast Asia during the boreal winter, mainly because of regular supplementary feeding. However, the use of supplementary food by eagles has not been assessed. In this study, we used non-invasive sampling and DNA metabarcoding to investigate the food composition of white-tailed eagles in a lake near a supplementary feeding site. Our results revealed that supplemental food was present in 94 % of the samples, with a weighted percent of occurrence (wPOO) of 64.62 %. In addition to supplementation, we identified 11 natural prey species, including fish, birds, and mammals, from freshwater, marine, and terrestrial ecosystems. After February, there was an increasing trend in the frequency of natural food items, especially of marine fish, in the diet of the eagles. Our study demonstrates the power of DNA metabarcoding in dietary studies of raptor species in the presence of supplementary feeding. Based on our results, multiple recommendations have been provided to achieve adaptive management of large nonbreeding populations of eagles in our study area.

Urban wetlands are an important part of the urban system and have very important ecological and social functions.Wetland city is an honorary initiative implemented by the Ramsar Convention to commend cities for their achievements in protecting wetlands.The Unit-ed Nations Sustainable Development Goals(SDGs)are the key to solving global problems.It is leading and guiding wetland protection and urban development.This study connects the wet-land cities with the United Nations Sustainable Development Strategy and attempts to explore new paths for synergy between urban development and wetland protection.(1)It sorted out the development history and certification process of wetland cities comprehensively,and summa-rized the experience of 13 wetland cities of China.(2)It introduced the three stages of sustain-able development,and summarized international initiatives related to wetlands and cities based on Sustainable Development Goals.(3)The future trend should aim to promote the exploration of sustainable development paradigms of wetland cities towards"international convention orga-nization-creation effectiveness monitoring-development indicator evaluation",and to enrich high-quality development practices of wetland cities towards"national strategic needs and local urban construction".This study provides technical support for intelligent decision-making ser-vices of urban wetlands focusing on"urban wetland remote sensing monitoring-urban wetland simulation prediction-urban wetland comprehensive assessment and services".

Industrial wastewater discharge has become the main cause of water pollution in China. However, the spatial interaction mechanism between industrial structure and water pollution is still unclear. Accordingly, we evaluated and analyzed spatiotemporal changes of the agglomeration pattern of pollution-intensive industrial enterprises and the evolution of the water environmental pollution pattern, as well as the correlation between them. The study results show that the polluting industrial enterprises were located mainly along the Yangtze River and Taihu Lake Basin in southern Jiangsu in 2013 and 2018. However, we observed a spatial trend of pollution transfer to northern Jiangsu. The industrial water pollution discharge presents the distribution pattern of facing rivers, seas, lakes and cities. Papermaking and paper products industry are the leading factors of COD and NH3–N pollution, with explanatory power of 0.3666 and 0.6201 respectively. The spatial positive coupling effect between the concentration degree of polluting enterprises and the intensity of water environment pollution discharge is 94.95% of the region. The spatial agglomeration of polluting industrial enterprises is an important cause of water environment pollution. They promote and couple each other, proving the existence of "Pollution haven" and "Porter hypothesis".

获取精细湿地资源信息对国际湿地城市湿地修复保护、管理利用以及区域可持续发展至关重要,目前面向国际湿地城市的湿地精细分类研究较为缺乏,尤其是针对湿地中水体的详细类别划分较少.本研究以全球典型国际湿地城市常德市为案例研究区,基于Google Earth Engine(GEE)云计算平台和2020年Sentinel-1/2时序遥感影像以及地形数据,首先采用最小冗余最大相关算法和递归梯度提升树算法进行湿地分类特征集优选,进而构建集成基于像元的随机森林和面向对象的知识规则决策模型的城市湿地精细分类智能模型,以实现常德市湿地资源精细分类.结果表明:(1)湿地分类特征优选前后特征数由63减少为16,总体精度下降0.9％,其中旱期的水体指数、植被频率和建成区指数的特征重要性较大,特征优选可以减少特征数据信息冗余、提高分类效率;(2)常德市湿地精细分类结果包括河流、湖泊、水库、养殖池/坑塘、运河/水渠、泥滩地、草滩地和芦苇湿地8种湿地类型,总体精度达91.53％,Kappa系数为0.89,可以满足国际湿地城市精细湿地分类的需求;(3)常德市湿地主要分布在东部西洞庭湖平原区域,呈现出东多西少的空间格局.本研究综合利用多源遥感数据、GEE云计算平台、机器学习算法以及知识规则模型能够准确高效地提取国际湿地城市精细湿地信息,有望迁移至其他城市湿地制图应用,在服务国际湿地城市创建及优选、湿地资源修复保护与可持续开发利用等方面具有较大应用潜力.

In 2015, the Sustainable Development Goals (SDG) replaced the Millennium Development Goals (MDG), providing guidance and direction for the future development of countries around the world. Both MDG and SDG have established multiple indicators to achieve environmental sustainability. However, few studies have compared the changes in the ecological environment during the two periods. Therefore, this study selected the seven major river basins in China as the study area and comprehensively assessed the changes in ecosystem service importance (ESI) within different basins in the MDG and SDG periods based on six ecosystem services, including habitat quality, soil conservation, water yield, carbon storage, grain production, and aesthetic landscape. Specifically, the changes from 2000 to 2015 and 2015 to 2020 were used to represent MDG and SDG periods, respectively. The results showed that the overall ESI of the seven major river basins showed an increasing trend in both periods, and the proportion of extremely important basins reached 20.39% in 2020, mostly distributed in the Yangtze River basin and the Pearl River basin. Except for carbon storage, other ecosystem services were restored in the SDG period. However, COVID-19 and a series of sudden disasters in 2020 have greatly affected grain production and the aesthetic landscape. The fluctuation of habitat quality also indicated that although the ecological environment has a trend of recovery, there was still some degradation compared to 20 years ago. National protection policies and restoration projects have gradually improved the ecological environment of the seven river basins and are striving to reach the SDG standards step by step. However, many problems still need to be solved urgently, such as the reduction of ecological land, the increase in carbon emissions, and the weak resilience to disasters. China has made significant positive progress in MDG, and more efforts are needed to achieve the SDG goals in the future.

Wetland cities were proposed by the International Wetland Convention Organization for the protection of urban wetlands. Few studies have performed land cover classifications for internationally recognized wetland cities or explored what contribution the classification results can make to the establishment of additional wetland cities to date. Based on Sentinel-1 and 2 data, this study used a 10-fold random forest method to classify the land cover of the first six wetland cities recognized in China. A land cover dataset, which had a resolution of 10 m and included four wetland types, was obtained and the wetland area and protected wetland areas of the six cities were calculated. The results showed that (1) the classification accuracy of six cities was good, the overall accuracy was above 90%, and the Kappa coefficient was above 0.88. (2) Cropland or forested areas were the most common non-wetland land coverage type in wetland cities and accounted for more than 20% or 40% of the land coverages, while water was the most common wetland type and accounted for more than 2% of the land coverages. From 2015 to 2020, the built area in most cities increased, while cropland and forest decreased significantly. (3) The wetland rate was 6.68–37.56% and the wetland protection rate was 49.48–73.74% in the six wetland cities. From 2015 to 2020, the wetland rate of the six cities were relatively stable, and the wetland protection rate of inland cities (Yinchuan, Changde, Harbin and Changshu) increased significantly, while those of coastal cities (Haikou and Dongying) decreased, which might be related to the change in coastline. Therefore, we found that the wetlands in these cities were well protected. Land cover classification for wetland cities can provide a reference for using remote sensing techniques used to monitor internationally wetland cities while also supporting the creation of additional wetland cities.

Wetlands provide vital ecological services for both humans and environment, necessitating continuous, refined and up-to-date mapping of wetlands for conservation and management. In this study, we developed an automated and refined wetland mapping framework integrating training sample migration method, supervised machine learning and knowledge-driven rules using Google Earth Engine (GEE) platform and open-source geospatial tools. We applied the framework to temporally dense Sentinel-1/2 imagery to produce annual refined wetland maps of the Dongting Lake Wetland (DLW) during 2015–2021. First, the continuous change detection (CCD) algorithm was utilized to migrate stable training samples. Then, annual 10 m preliminary land cover maps with 9 classes were produced using random forest algorithm and migrated samples. Ultimately, annual 10 m refined wetland maps were generated based on preliminary land cover maps via knowledge-driven rules from geometric features and available water-related inventories, with Overall Accuracy (OA) ranging from 81.82% (2015) to 93.84% (2020) and Kappa Coefficient (KC) between 0.73 (2015) and 0.91 (2020), demonstrating satisfactory performance and substantial potential for accurate, timely and type-refined wetland mapping. Our methodological framework allows rapid and accurate monitoring of wetland dynamics and could provide valuable information and methodological support for monitoring, conservation and sustainable development of wetland ecosystem.

As the second batch of international wetland cities, Wuhan and Nanchang, both provincial capital cities in China, have abundant wetland resources. An important sign of achievement of protecting the urban wetland areas is the international wetland city designation. Understanding the growth and changes of wetlands in international wetland cities is necessary for wetland protection and management. Thus, it is crucial to conduct proper wetland mapping in these international wetland cities. By studying wetland cities, sustainable planning can be provided to promote the coordinated development of wetlands and cities. In this research, Google Earth Engine and random forest machine learning were used. According to the "Data-Information-Knowledge-Wisdom" research framework, we carried out mapping of diverse wetlands in Wuhan and Nanchang with a resolution of 10 m in 2015 and 2020. Then, using the findings of wetland mapping, we examined changes in the wetland landscapes of the two cities. Finally, this study examined changes in international wetland city indicators over this time frame. The research results are as follows. 1) Our wetland mapping results in 2015 and 2020 achieved good accuracy, with an overall accuracy of over 0.90 and a kappa coefficient of over 0.85. 2) The total wetland area in both cities increased. Nanchang grew by 91.11 km(2), whereas Wuhan grew by 290.68 km(2). Most restored wetland areas were far from urban construction areas. In the two cities, the fragmentation of wetlands decreased, the diversity of wetlands increased, and the growth rate of wetlands was high. 3) Wetland rates rose from 17.79% to 19.07% in Nanchang and from 19.74% to 23.12% in Wuhan, according to mapping results between 2015 and 2020. The wetland protection rate in Nanchang remained unchanged, but the wetland protection rate in Wuhan decreased. Wuhan needs to strengthen the protection of increased wetlands. In addition, the study found that most of the increased areas of wetlands were previously cultivated land. The international wetland mapping framework of this study can be easily implemented in other regions of the world.

With the development of social economy and the influence of human activities, land use has undergone great changes. Land use prediction models have gradually emerged for more rational planning and development of the region. This study took Changshu and Haikou, two wetland cities, as examples to explore the prediction effects of land and fine wetland types in PLUS, FLUS and CLUES models, and combined CA-Markov model to make a detailed summary of the composition, use requirements, advantages and disadvantages of each model. The results showed that: (1) From 2015 to 2020, the urban area in Changshu and Haikou showed a significant increase, with growth rates of 16.61% and 21.37%, respectively. However, the total area of wetland remained above 10%, which was not greatly affected; (2) The average overall accuracy of the PLUS, FLUS and CLUES models in the prediction of Changshu and Haikou was 0.85, 0.86, and 0.84, respectively, while Kappa was 0.79, 0.81, and 0.78, respectively. Especially, the prediction in the fine wetland types also achieved high accuracy. (3) FLUS and CLUES had more stable results in the comparison of spatial results, deviation on the prediction of some land use categories was easily born in PLUS. Each model has its own advantages and disadvantages in practical application and operation. The research results of this paper are intended to let more people understand different land use prediction models and provide reference basis for the improvement and application of the models.

基于色木枫的转录组数据初步设计166对引物,并根据琼脂糖凝胶电泳与Sanger测序结果筛选出其中的26对核低拷贝基因引物.在东亚63个种群的182个个体中大批量扩增所开发引物,单倍型多样性范围为0.45～0.97,核苷酸多样性为(1.90～18.03)×10-3;9～15对引物可在金钱械、茶条槭、青榨槭和鸡爪槭中扩增;STRUCTURE聚类结果与之前核微卫星研究结果类似,且展示了更多的谱系地理结构,结果表明引物多态性高、拓展性强、具有可靠性.本研究的转录组数据为槭属的研究提供重要遗传信息,所用方法被证明可以有效开发大量核低拷贝基因引物,已开发出的26对引物将为色木枫的进化历史和槭属系统发育研究提供丰富有效的分子标记.

Understanding the variation regularity of water extent can provide insights into lake conservation and management. In this study, inter- and inner-annual variations of water extent during the period of 1987–2020 were analyzed to understand the temporal and spatial distribution characteristics of Dongting Lake. We applied the Multiple Index Water Detection Rule to extract the Dongting Lake water extent quickly and accurately based on Google Earth Engine platform, and then assessed the extraction accuracy. The water surface analysis results showed that (1) based on sustainable development goals (SDG) 6.6.1, the trend of water extent showed the downward fluctuating trend from 1987 to 2020, with the overall average water extent being 1894.48 km². (2) Among the monthly average water area, the largest extent was 2477.14km² (July) and the smallest was 848.14 km² (January). Among the seasonal mean water area, summer was the largest, with an area of 2438.06 km², and winter was the smallest at 967.34 km². (3) For the water inundation frequency, seasonal water bodies accounted for the largest proportion, with 1577.85 km²; the nonwater area was the smallest, with the area of 573.02 km²; and the permanent water area was 1086.21 km². Through the analysis of the historical water body extent of the long time series of Dongting Lake, this study reflected support for SDG, for which the research idea and design can help us understand the importance and feasibility of the SDG 6.6.1 indicator.

As one of the most open and dynamic regions in China, the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) has been urbanizing rapidly in recent decades. The surface water in the GBA also has been suffering from urbanization and intensified human activities. The study aimed to characterize the spatiotemporal patterns and assess the losses and gains of surface water caused by urbanization in the GBA via long time-series remote sensing data, which could support the progress towards sustainable development goals (SDGs) set by the United Nations, especially for measuring SDG 6.6.1 indicator. Firstly, utilizing 4750 continuous Landsat TM/ETM+/OLI images during 1986–2020 and the Google Earth Engine cloud platform, the multiple index water detection rule (MIWDR) was performed to extract surface water extent in the GBA. Secondly, we achieved surface water dynamic type classification based on annual water inundation frequency time-series in the GBA. Finally, the spatial distribution and temporal variation of urbanization-induced water losses and gains were analyzed through a land cover transfer matrix. Results showed that (1) the average minimal and maximal surface water extents of the GBA during 1986–2020 were 2017.62 km2 and 6129.55 km2, respectively. The maximal surface water extent fell rapidly from 7897.96 km2 in 2001 to 5087.46 km2 in 2020, with a loss speed of 155.41 km2 per year (R2 = 0.86). (2) The surface water areas of permanent and dynamic types were 1529.02 km2 and 2064.99 km2 during 2000–2020, accounting for 42.54% and 57.46% of all water-related areas, respectively. (3) The surface water extent occupied by impervious land surfaces showed a significant linear downward trend (R2 = 0.98, slope = 36.41 km2 per year), while the surface water restored from impervious land surfaces denoted a slight growing trend (R2 = 0.86, slope = 0.99 km2 per year). Our study monitored the long-term changes in the surface water of the GBA, which can provide valuable information for the sustainable development of the GBA urban agglomeration. In addition, the proposed framework can easily be implemented in other similar regions worldwide.

Abstract Secondary contact zones can provide valuable evolutionary and ecological insights for elucidating patterns of divergent lineage evolution. The tertiary relict flora in East Asia can be divided into northern (“NEA”) and southern (“SEA”) regions. To date however, secondary contact zones of lineages from the NEA and SEA regions have rarely been studied. To test whether introgression occur between the ancient lineages and their evolutionary and ecological consequences, we conducted detailed genetic and ecological work within a maple hybrid zone in North China. Genetic structures of both adults and seeds populations were characterized. Spatial genetic pattern was checked along an altitude gradient. Flowering phenology was analyzed to test the existence of assortative mating. Leaf and fruit morphologies were compared between lineages. Our study confirm introgression occur between NEA and SEA lineages. Post-pollinator barriers predominantly contribute to a reduction in interlineage gene flow. Ecological niche differs between lineages along an altitudinal gradient. We clarify a long-standing classification debate with respect to Acer pictum subsp. mono and A. truncatum, though there are extensive morphological variation and overlaps between the species pair. Our study represents the first few detailed evolution and ecological investigation focusing on ancient NEA-SEA lineages hybrid zone.

Sustainable Development Goals (SDGs) target 11.a is a good vision for the coordinated development of the economy, society and environment in urban agglomerations. However, there was an extreme lack of indicators, data or case studies for SDG target 11.a, since it is a vague “process target”, which is not conducive to the implementation of SDG target 11.a. It is important to propose a quantitative, convenient, and local policies relevant method to promote the realization or to test the implementation effects of SDG target 11.a. Combined with socio-economic data and land use data, this study uses the methods of comprehensive evaluation model, coupling and coordination degree, and comparative advantage degree methods to study the pattern evolution, coordination characteristics and advantageous areas of production–living–ecological (PLE) functions in the Guangxi Beibu Gulf Urban Agglomeration (GBG_UA) from 1995 to 2019. The results showed that, (1) considering the spatiotemporal distribution of PLE functions, the study area has a relatively stable ecological function as well as fluctuating production and living functions. Considering the coordination characteristics of PLE functions, high–high and low–low clustering effects were observed, and primary coordination maintained the highest proportion, accounting from 55.26% in 1995 to 71.05% in 2019, indicating the SDG target 11.a level in the GBG_UA was poor. Considering the advantageous areas for PLE functions, the region mostly comprises single-function advantageous areas and a few multifunction advantageous areas, including 20 single-function advantage counties (accounting for 52%), 15 dual-function advantage counties (accounting for 39%), and three multi-function advantage counties (accounting for 7.8%), which indicates the lack of diversified land use structures in this region. (2) Optimization suggestions for the coordinated development and realization of SDG target 11.a for the GBG_UA were provided. Suggestions were made based on the radiation and driving role of Nanning city to guide the coordinated development of surrounding counties (districts). Suggestions were also made to improve the design of the integrated transportation network as well as to optimize allocation according to the resource endowment of land and to realize an upgraded ecology as well as agricultural products and services. (3) The evaluation of PLE functions is a quantitative and convenient method that can optimize national and regional development planning and test the implementation effects of SDG target 11.a. This study offers foundational knowledge for the realization of SDG target 11.a in the GBG_UA and provides a reference for the research and implementation of SDG target 11.a in other regions around the world.

Wetland carbon storage plays an essential role in the global carbon cycle. However, in recent decades, intensive human activities and rapid urbanization have reduced wetland C stocks in the Guangdong–Hong Kong–Macau Greater Bay Area (GBA). Long-term assessment of carbon storage in the wetland ecosystems of the GBA is needed for promoting regional sustainable development. Therefore, we proposed a framework integrating the integrated valuation of ecosystem services and tradeoffs (InVEST) model and water inundation frequency, which was retrieved via multiple index water detection rule based on Google Earth Engine platform, to estimate yearly carbon storage in wetlands across the GBA at a 30-m spatial resolution during 1995–2020. The incorporation of water inundation frequency in estimating carbon storage in wetlands presents features of long time series and higher temporal frequency. The results showed that: first, the carbon storage of wetlands estimated by the InVEST model decreased from 33.38 to 16.64 Tg·C between 1995 and 2020 in the GBA, mainly owning to the loss of paddy fields. Second, there is a significant exponentially decreasing relationship between water inundation frequency and carbon storage density within the potential wetland extent, with the R2 reaching 0.998, which denotes huge potential for estimating wetland carbon storage; third, annual wetland carbon storage estimated were divided into three main stages: a rapidly increasing period (1995–2004), a falling period (2005–2013), and a slightly fluctuating period (2015–2020). This research may provide references for supporting decision-making in implementing wetland-related sustainable development and carbon-neutrality policies in the GBA.

河源区边界是重要的国家基础地理信息之一,但除长江、黄河等大江大河外的我国大部分其他中小流域仍缺乏确切的河源区边界信息,需要科学划定河源区边界以支持流域水生态保护相关政策的规划与实施.对此,本文在确立河源区划分原则、明确划分依据的基础上,提出了基于多特征指标和层次聚类分析法的河源区边界划定方法.以沁河流域为研究案例,首先利用均值变点分析法计算沁河流域子流域提取的最佳汇流累积量分位数阈值为0,15％,再基于子流域的多特征指标运用层次聚类分析法最终确定河源区范围边界,并将该方法应用于长江、黄河流域进行验证分析.结果表明:①基于多特征指标和层次聚类分析提取的沁河流域河源区范围处于河底比降法、水文站点方法得到的源区范围面积之间;②该方法在长江、黄河流域河源区划分结果的交并比分别达到85.40％和79.99％,侧面验证了本文方法进行河源区边界划分的合理性与适用性.基于多特征指标和层次聚类分析的河源区边界自动划分方法可以简捷高效地识别缺乏明确河源区边界信息的流域河源区范围,为我国河源区生态安全屏障识别、水资源保护相关政策的规划和实施提供科学支撑.