Wetlands In China Research Articles

Assessing the performance of the Tiangong-2 wide-swath imaging altimeter observations for water level monitoring over complex and shallow lakes

As a significant hydrological parameter, the water level of complex and shallow river-lake wetland has important implications for a number of hydrological, biological, physical and chemical processes. Current in-situ and satellite-based methods both have disadvantages in capturing water levels over smaller surface water bodies with spatial heterogeneity or complexity. Interferometric imaging radar altimeter (InIRA) is a latest generation of Ku-band radar altimeter onboard Tiangong-2 (TG-2), the Chinese space laboratory, launched in 2016. Similar to the design idea of NASA’s SWOT, it is expected to improve this situation through wide-swath altimetry. However, the capacity of the TG-2 InIRA to measure water levels within small surface water bodies remains unexamined. To explore these performances, particularly their potential impact on hydrology research, an assessment and comparison between in-situ and TG-2 derived measurements was performed over the largest river-lake wetland in China. The results showed that the TG-2 InIRA, with a broad range of coverage, was able to effectively capture most of the surface water at its elevation. For the focused shallow depressions, a relatively good correlation was observed between the in-situ and InIRA-derived water surface elevations (WSEs), with an R2 of 0.97, RMSE of 0.29 m, and absolute difference ranging from 3 to 55 cm. The accuracy of InIRA-derived WSEs was highly controlled by the depression sizes, and the absolute biases broadly increased in a power law fashion as the size of the depression decreased. In addition, surface water profiles along the Ganjiang and Xiushui River channels indicated that the TG-2 InIRA could also measure river WSEs, with absolute differences below 0.43 m. Although differences were observed, the results of the river gradient distribution were consistent with the practical situation and showed overall slopes of 18.72 cm/km and 12.43 cm/km for the Xiushui and Ganjiang Rivers, respectively. Such results demonstrated that TG-2 InIRA measurements can satisfactorily capture spatial patterns of the surface water gradient, which is useful for accurately estimating river discharge. This study will not only bridge the gap between in-situ measurements and forthcoming SWOT products but also contribute to water resource management and hydrologic service assessments over data-sparse regions of river-lake systems within the study area.

Effects of Spartina alterniflora Invasion on Soil Organic Carbon Storage in the Beihai Coastal Wetlands of China

The invasion of Spartina alterniflora (S. alterniflora) has changed the carbon cycle process of local ecosystems. In order to clarify the effect of S. alterniflora invasion on coastal soil carbon pool in Northern Beibu Gulf, the distribution characteristics and influencing factors of soil organic carbon (SOC) and SOC storage (SOCS) at different intrusion stages were investigated and analyzed. The results showed that the SOC content in S. alterniflora wetlands (2.65–21.54 g/kg) was higher than that in mudflats (0.85–1.19 g/kg). SOC content in 0–20 cm depth was highest than that in 20–40 cm and 40–60 cm depth. The total SOCS increased by 72.11%, 78.45%, 77.56%, 80.42%, and 90.63% in 3a, 12a, 15a, 16–19a, and 26a compared with mudflats, respectively. S. alterniflora invasion increased SOC and SOCS both in surface soil and deep soil. SOCS increased rapidly during the initial stage of invasion, and remained in a relatively stable and continuous growth state after 12–15 years. The distributions and accumulation of SOC and SOCS were affected mainly by soil texture, soil bulk density, moisture content, total nitrogen and total phosphorus. The source of SOC from S. alterniflora was increasing with invasion ages and would be mainly input in 26a, while marine sources was mainly imported in other invasion ages. Our data indicated that S. alterniflora continuously enhances the SOC sequestration over the years in coastal wetland ecosystems.

PSR-BP Neural Network-Based Health Assessment of the Huangshui Plateau Urban Wetlands in China

Wetland health assessment provides important basis for wetland restoration and management. However, it is quite tricky to select proper indicators from multiple assessment indicators that can truly reflect the health state of urban wetlands. In an attempt to address these problems, a pressure-state-response (PSR) and back propagation artificial neural network (BP) conjoined model was established for health assessment of several plateau urban wetlands in Xining City, China. The model was driven and verified through field monitoring and social questionnaire data for 4 consecutive years from 2016 to 2019. Results indicate that: (1) Eight health evaluation indexes, including population density, eutrophication level, increasing humidity, carbon dioxide absorption, air purifying, recreation, wetland management level and investment in ecological construction and protection were selected from 45 input indexes. (2) The health index of Huangshui National Wetland Park has been increasing year by year, with an average of comprehensive health score of 0.746, 0.790, 0.884, and 0.877, respectively. The indicators that contributed the most to the restoration effect were leisure and entertainment service value (2016), carbon dioxide absorption service value (2017), eutrophication (2018), and wetland management level (2019), respecially. (3) Compared with the single PSR method, the advantages of this method include; There are fewer evaluation indicators, more accurate results (excluding the interference of some highly variable indicators) and more sensitive to environmental changes. The current study proposed a novel method that may provide additional accurate and refined indicators for urban wetland health assessment.

Wetlands in China: Evolution, Carbon Sequestrations and Services, Threats, and Preservation/Restoration

China has a wetland area of 53.42 million hectares, the fourth largest in the world; it includes all types of wetlands defined by the Ramsar Convention and has a carbon sink capacity of more than 1.71 million metric tons per year. Inland wetlands in China are mainly distributed in 10 major catchments, among which the Yellow River, the Yangtze River, the rivers in the northwest, and the rivers in the northeast each have more than 8 million hectares of wetlands. There are 4220 species of plants and 4015 species of animals in China’s wetland ecosystem. The wetland resources that have been developed and utilized include edible products, reeds for paper making, peat for fertilizer, fuel for power generation, and chemical, pharmaceutical, ceramic, and building materials. However, wetland areas in China have shrunk by about 54% since 1980. In recent years, China’s central government has set great store by Chinese wetlands, and although 49.03% of wetland area is now officially protected, many issues have confounded the implementation of that protection. It is imperative that knowledge gained from scientific research be used to formulate a sound wetland protection and management plan that takes into consideration social, economic, and ecological issues in a way that facilitates the sustainable use of wetland resources and informs decision-makers of the paths that must be followed to achieve that goal.

A new contribution to the taxonomy and phylogeny of the ciliate genus Spirostomum (Alveolata, Ciliophora, Heterotrichea), with comprehensive descriptions of two species from wetlands in China

Species of the ciliate genus Spirostomum Ehrenberg, 1834 are distributed worldwide and have a research history spanning more than two centuries. However, species delimitation and phylogenetic relationships within this genus are still uncertain due to the paucity of stable morphologic characters for species separation and the unavailability of accompanying morphological data for most molecular sequences in public databases. In the present study, S. yagiui Shigenaka, 1959 (three populations) and S. caudatum (Müller, 1786) Delphy, 1939 (one population) were investigated using morphological and molecular methods for the first time in China. Detailed morphological data for the two species were documented, and improved diagnoses were supplied based on a combination of previous studies and the current work. It should be highlighted that there were three different atypical morphotypes identified in a Ningbo population of S. yagiui which may represent various stages in conjugative reproduction. Molecular phylogenies based on 18S, ITS1-5.8S-ITS2, and 28S rRNA gene sequences show that the genus Spirostomum is monophyletic, however, the internal relationships inferred from different genes were poorly resolved but suggest that the species with a moniliform macronucleus comprise an early-diverging clade within this genus. Finally, the global distribution of Spirostomum is summarized based on previous and present studies.

Development of a Landscape-Based Multi-Metric Index to Assess Wetland Health of the Poyang Lake

Human-induced changes in landscapes are one of the major drivers of wetland loss and degradation. The Poyang Lake wetland in China has been experiencing severe degradation due to human disturbance and landscape modification. Indicators to assess the condition of this wetland are thus needed urgently. Here, a landscape-based multi-metric index (LMI) is developed to evaluate the condition of the Poyang Lake wetland. Twenty-three candidate metrics that have been applied to wetland health assessment in published studies were tested. Metrics that show strong discriminative power to identify reference and impaired sites, having significant correlations with either benthic macroinvertebrate- or vegetation-based indices of biotic integrity (B-IBI or V-IBI), were chosen to form the LMI index. Five of these metrics (largest patch index, modified normalized differential built-up index, Shannon’s diversity index, connectance index, and cultivated land stress index) were selected as our LMI metrics. A 2 km buffer zone around sample sites had the strongest explanatory power of any spatial scale on IBIs, suggesting that protecting landscapes at local scales is essential for wetland conservation. The LMI scores ranged between 1.05 and 5.00, with a mean of 3.25, suggesting that the condition of the Poyang Lake wetland is currently in the “fair” category. The areas along lakeshores were mainly in poor or very poor conditions, while the less accessible inner areas were in better conditions. This study demonstrates significant links between landscape characteristics and wetland biotic integrity, which validates the utility of satellite imagery-derived data in assessing wetland health. The LMI method developed in this study can be used by land managers to quickly assess broad regions of the Poyang Lake wetland.

Evaluation and analysis of ecosystem service value based on land use/cover change in Dongting Lake wetland

Wetland vegetation has experienced significant loss and degradation over the last few decades. Although volumes of studies involve wetlands, limited attention has been paid to the long-term changes and ecological values of inland lake wetlands in China. In this paper, land use/cover data of Dongting Lake wetland from 1995 to 2020 was generated based on Google Earth engine using Stacking algorithm. Subsequently, the spatial and temporal variation of wetland types was explored using dynamic analysis and correlation indices of land change. The main factors influencing the distribution of wetland vegetation were identified by Geodetector. Finally, the degree of impact of wetland changes on ecosystem service value was quantified based on the equivalence factor method. The results show that, in the past 25 years, wetland land use types had switched with each other more frequently, and a total of 294.94 km2 of wetland area had been lost, mainly due to the shrinkage of water, reeds and sedge. The main factors affecting wetland distribution are population density, GDP, elevation and sunshine duration, and the interaction of the drivers is mostly linearly enhanced with no weakening effect. In addition, the ecosystem service value of wetlands showed a trend of first decreasing and then increasing, with a total loss of ¥87,000.99 million in wetland ESV. The results of the study can provide basic information and data for the preliminary work of planning and design, and demonstrate the importance of ecosystems in different regions. Based on the assessment results, it can provide an important basis for the construction of ecological security patterns and policy formulation for ecological civilization construction.

Conserving unprotected important sites for shorebirds on China's coasts

AbstractThe loss of natural wetland habitats along China's coasts has contributed to population declines in waterbirds, especially migratory shorebirds. Identifying important shorebird sites is important for habitat conservation and management. We integrated shorebird survey datasets from multiple sources (bird‐watching websites, survey reports, and published literature) for coastal wetlands in China and used the criterion of 1% of the global or flyway population (hereafter, Ramsar 1% criterion) and priority index Pi to identify conservation priority sites and corresponding prioritization rank. We used gap analysis to identify the conservation status of natural protected areas. Forty‐eight conservation priority sites, where 31 shorebird species met the Ramsar 1% criterion. The prioritization rank was very high priority for six sites, high priority for five sites, and priority for 37 sites. There were 28 conservation priority sites for shorebirds with conservation gaps, and these accounted for 58.33% of all 48 conservation priority sites. Of these unprotected sites, the prioritization ranks were very high priority or high priority for six sites, which were mainly concentrated in Jiangsu province. We recommend prioritizing the protection of these sites by creating new protected areas or incorporating these areas into the existing system.

Growth and physiological response of Kandelia obovata and Bruguiera sexangula seedlings to aluminum stress

The role of mangroves as a biogeochemical buffer for heavy metal pollutants in coastal wetlands has been demonstrated, but knowledge gaps still exist on the tolerant capacity of mangroves to aluminum (Al). This study assessed the growth and physiological response of viviparous mangroves Kandelia obovata and Bruguiera sexangula to Al stress. The two mangrove seedlings were treated with AlCl3 at concentrations of 0 (as control) to 100 mmol L−1, and the impact of Al on their growth and antioxidant parameters were determined. Additionally, the accumulation and translocation of metal elements were estimated in B. sexangula seedlings under relative long-term Al stress. K. obovata appeared to survive with a tolerance potential of 10 mmol L−1 AlCl3, whereas B. sexangula had a higher tolerant ability of 50 mmol L−1 AlCl3. Both root elongation and seedling growth were inhibited by Al stress. The exposure to 25–100 mmol L−1 AlCl3 induced increases in membrane lipid peroxidation and osmoprotectant molecule (proline) in mangrove seedlings. Both mangrove seedlings revealed significant changes in antioxidant enzyme activities that were attributed to Al stress-induced oxidative damages. The activities of superoxide dismutase, catalase, peroxidase, and/or ascorbate peroxidase were differently impacted by the treatment time (7 days for short term versus 60 days for long term) and AlCl3 concentrations in K. obovata and B. sexangula seedlings. For B. sexangula seedlings, Al accumulation was in an order root > leaf > stem, whereas the translocation of metal elements in the aboveground tissues (leaf and stem) was differently impacted by Al stress. In conclusion, this study provides insights into different Al-tolerant abilities operated in two mangrove species that are widespread in coastal wetlands of China.

The Impacts of a Large Water Transfer Project on a Waterbird Community in the Receiving Dam: A Case Study of Miyun Reservoir, China

As natural wetlands are degrading worldwide, artificial wetlands can operate as a substitute to provide waterbirds with refuge, but they cannot replace natural wetlands. Reservoirs, one of the most common artificial wetlands in China, can be of great importance to waterbirds. Miyun reservoir in Beijing, China, has undergone a process similar to a natural lake being constructed in a reservoir. In this study, we surveyed waterbird community composition and evaluated the corresponding land cover and land use change with satellite and digital elevation model images of both before and after the water level change. The results showed that in all modelled scenarios, when the water level rises, agricultural lands suffer the greatest loss, with wetlands and forests following. The water level rise also caused a decrease in shallow water areas and a decline in the number and diversity of waterbird communities, as the components shifted from a shallow-water preferring group (waders, geese and dabbling ducks) to a deep-water preferring group (most diving ducks, gulls and terns). Miyun reservoir ceased to be an important waterbird habitat in China and is no longer an important stopover site for white-naped cranes. A similar process is likely to occur when a natural lake is constructed in a reservoir. Therefore, we suggest that policymakers consider the needs of waterbirds when constructing or managing reservoirs.

Wetland classification using parcel-level ensemble algorithm based on Gaofen-6 multispectral imagery and Sentinel-1 dataset

Wetland ecosystems have experienced dramatic challenges in the past few decades due to global climate change and human activities. Wetland maps are essential tools for conservation and management of terrestrial ecosystems. The objective of this study was to obtain an accurate wetland map using a parcel-level ensemble method based on Sentinel-1 SAR time series and segmentations generated from GF-6 MPS images. The Dongting Lake wetlands in China, which has a heterogeneous landscape, was deliberately chosen as a challenging case study. First, both VV and VH polarization backscatters (σ0 VV, σ0 VH) were generated from time series Sentinel-1 SAR. Speckle noise inherent in SAR data can affect the performance on image segmentation by resulting in over-segmentation or under-segmentation, and that will degrade the accuracies of wetland classification. Subsequently, optical data (Gaofen-6), which is effectively capable of delineating meaningful parcels, were applied to get the segmentations in this study. Finally, the ensemble method was utilized to extract the wetland information at parcel-level. The overall accuracy and Kappa coefficient of the object-based ensemble method are 90.58% and 0.88, which are 4.25% and 0.04 higher than that of the pixel-based method, respectively. Moreover, the object-based ensemble method for classification in high heterogeneity areas is superior and can greatly improve the performance compared with single classifiers.

Research status of heavy metal pollution evaluation in urban wetlands in China

Urban wetlands are one of the ecosystems most closely related to human production and life, and have various functions such as stabilizing the environment, improving the urban environment, regulating and storing floodwater, supplementing groundwater, recreation, science and education culture, and protecting biodiversity. With the continuous shrinkage of urban wetlands in recent years and frequent pollution, many scholars at home and abroad have carried out a lot of research work on urban wetlands, of which the evaluation of heavy metal pollution in urban wetlands is one of the priorities. In this paper, this paper analyzes the reports on heavy metal pollution in urban wetlands in China in recent years, reviews the current situation of pollution evaluation in sediment, soil and water bodies of urban wetlands, and summarizes and summarizes the pollution evaluation methods of heavy metals. Among the many evaluation methods, the single index method, the ground accumulation index method, the potential ecological risk assessment method and the water quality standard level method are the most used.

中国湿地生态站现状、发展趋势及空间布局

PDF HTML阅读 XML下载 导出引用 引用提醒 中国湿地生态站现状、发展趋势及空间布局 DOI: 10.5846/stxb202104130960 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院A类战略性先导科技专项（XDA23040203）；国家自然科学基金项目（42171105，41971133）；国家生态系统观测研究共享服务平台建设项目 Current status, development and spatial planning of China's Wetland Ecological Stations Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:湿地调查与监测是全面了解和掌握湿地变化，开展湿地保护和修复的前提和基础。湿地生态站是开展湿地长期监测和野外试验的平台，对研究湿地生态系统过程与功能，揭示湿地变化机理具有重要作用。系统梳理了我国现有的湿地生态站，分析了当前湿地生态站建设中面临的问题，指出：与国际主要生态观测网络相比，我国综合性湿地生态站数量较少、比例偏低，导致在湿地生态系统监测和评估上存在较大空缺；现有生态站存在层级结构不合理、监测指标体系不规范等问题，制约了国家尺度湿地生态系统监测评估的需求。研究基于中国湿地生态站的现状，提出综合性湿地生态站布局原则，认为：应反映湿地生态系统类型代表性及湿地的空间分布特征，体现综合站-区域站-卫星站的层级结构特点，服务国家湿地保护和生态修复的战略需求。按照上述布局原则，对今后综合性湿地生态站的空间布局提出建议。同时，对湿地站发展定位、聚焦的前沿科学问题、湿地联网研究及国际合作方面提出了展望。 Abstract:Wetland survey and monitoring is the prerequisite and foundation for comprehensively understanding and clarifying wetland ecosystem dynamics, and carrying out wetland conservation and restoration. Wetland Ecological Stations provide the platform for long-term wetland observation and in-situ experiments, which are indispensable in studying and revealing the processes, functions, as well as related mechanism of wetland change. There are some problems in the development of wetland ecological stations in China. Compared with the International Long-Term Ecological Research Network, the number and proportion of Wetland Ecological Stations in National Ecological stations are less and there are also some gaps on spatial planning of wetland ecological stations; in addition, wetland ecological stations are not laid out with obvious hierarchical structure (such as Master stations, Regular stations and Satellite stations), and the monitoring indicators and systems for wetland ecological stations are also not standard and uniform, which lead to limitations on monitoring and assessment of wetland ecosystem at national scale. In this study, we summarized and analyzed the status and problems in the development of Wetland Ecological Stations in China, and proposed the planning principles of the National Wetland Ecological Stations in existing National Ecological Stations System. We suggested that it should consider representativeness of wetland ecosystem types and the spatial distribution characteristics of wetlands in China, as well as to take account of the hierarchical structure of wetland stations and their combination to national development strategy and policy demand on wetland conservation and restoration. We proposed some targeted suggestions on spatial planning of China's Wetland Ecological Stations in the future based on the above principles. At the same time, the development orientation of wetland station was determined and the frontier and key scientific issues needing to be focused in the future were discussed, such as the changes of wetland landscape, lake eutrophication and invasive species control, climate change and carbon sequestration mechanism, etc. Finally, how to response to the national development strategy and policy demand was also analyzed. It is proposed to strengthen cooperation with international partners in the fields of biodiversity conservation and monitoring, climate change, transboundary wetlands and the conservation of migratory species. 参考文献 相似文献 引证文献

Detecting the non-breeding region and migration route of Whimbrels (Numenius phaeopus rogachevae) in the East Asian–Australasian Flyway

Determining the migration routes and connections of migratory birds at the population level helps clarify intraspecific differences in migration. Five subspecies have been recognized in the Whimbrel (Numenius phaeopus) in Eurasia. Ssp. rogachevae is the most recently described subspecies. It breeds in Central Siberia, while its non-breeding region and migration routes are still unclear. We tracked the migration of Eurasian Whimbrels captured at three non-breeding sites (Moreton Bay in east coast of Australia, Roebuck Bay in Northwest Australia and Sungei Buloh Wetland in Singapore) and two migration stopover sites (Chongming Dongtan and Mai Po Wetland in China). We determined the breeding sites and inferred the subspecies of the tagged birds in the East Asian – Australasian Flyway (EAAF) based on the known breeding distribution of each subspecies. Of the 30 tagged birds, 6 and 21 birds bred in the breeding range of ssp. rogachevae and variegatus, respectively; one bred in the presumed transition area between the breeding range of ssp. phaeopus and rogachevae, and two bred in the region between the breeding range of ssp. rogachevae and variegatus. The birds that bred in the ssp. rogachevae breeding range spent their non-breeding season in the northern Sumatra, Singapore, East Java and Northwest Australia and mainly stopped over along China's coasts during migration. None of our birds bred in the exclusive breeding range of the phaeopus subspecies. Previous studies have predicted that rogachevae whimbrels migrate along the Central Asian Flyway and spend the non-breeding season in West India and East Africa. We found that at least some rogachevae whimbrels migrate along the EAAF and spend the non-breeding season in Southeast Asia and Australia. The ssp. phaeopus is at best sparsely distributed in the EAAF in the west region, or possibly does not occur at all.

A New Species of Free-living Marine Nematode (Ptycholaimellus: Chromadoridae: Chromadorida: Nematoda) from Mangrove Wetlands in China.

This study presents a new species of free-living marine nematode, Ptycholaimellus luoyang sp. nov., from mangrove wetlands in China. The identification was confirmed by analyzing morphological characteristics and three genes: COI, 18S rDNA, and 28S rDNA. This species is distinguished from allied species by its short cephalic setae, cylindrical pharynx with anterior swelling, sclerotized transverse ridges occurring near the dorsal tooth, rod-like gubernaculum and proximal, arch-like, slightly waved, middle curved, and distally pointed spicules. The Bayesian topology was regarded as morphological evidence of P. luoyang sp. nov. being a distinct species. Interspecific and intrageneric thresholds of the K2P distance divergence have been presented here for the first time.

基于地表土壤动物与植物完整性指数评估若尔盖沼泽湿地受扰现状

利用地表土壤动物与植物群落生物完整性指数评价若尔盖沼泽湿地受扰现状，为若尔盖沼泽湿地恢复提供依据。2018年7月与2019年7月对若尔盖10处典型湿地（参照区4个，受扰区6个）地表土壤动物与湿地植被群落进行调查。通过对74个候选指标的分布范围、判别能力及相关分析，确定中生性植物、一年生植物、龙胆科植物、一年生植物/多年生植物比4个植物核心指标，地表土壤动物总个体数量、中小型动物类群数量、蜘蛛目物种数量、菌食性土壤动物与腐食性土壤动物5个核心指标，构建若尔盖沼泽湿地地表土壤动物与植物完整性指数。以所有采样点95%分位数为最佳期望值，四分位法确定研究区域未受干扰、轻度干扰程度、中度干扰与重度干扰4个等级，作为判断若尔盖沼泽湿地受扰状况。结果显示，若尔盖沼泽湿地相对原始沼泽、花湖沼泽化草甸2、长期低强度排水疏干区、短期高强度排水疏干区分别处于未受干扰、轻度干扰、中度干扰与重度干扰状态。所调查的若尔盖典型湿地中，20%的湿地未受到干扰，30%的湿地受到轻度干扰，30%的湿地受到中度干扰，20%的湿地受到重度干扰。Pearson相关系数分析显示，地表土壤动物完整性指数与植物完整性指数存在显著正相关关系（r=0.722，P<0.05），表明地表土壤动物完整性指数与植物完整性指数评价结果具有一致性。;The Zoige wetland, located at the northeast of Qinghai-Tibet Plateau, is the largest plateau wetland in China. There have been substantial changes in Zoige wetland due to natural (climate, soil, and vegetation) and anthropogenic (drainage and overgrazing) impacts. The index of biotic integrity is a comprehensive method for assessing the ecological status of wetlands. The ground-dwelling soil animal and wetland plant are the most widely used biological indicators owing to their distinct advantages for wetland ecosystem monitoring, while there is no indicator framework to determine the disturbed status and benefit of returning grazing to wetland of the Zoige area. The aim of this study is to evaluate disturbance status of Zoige wetland using the ground-dwelling soil animal and wetland plant-based index of biotic integrity to providing data for the restoration of Zoige wetland. In July 2018 and July 2019, the ground dwelling soil animal and plant were investigated from 10 typical wetlands of Zoige were chosen, including 4 wetlands which were undisturbed or less disturbed, and 6 wetlands which were disturbed. The ground-dwelling soil animal and plant-based index of biotic integrity in Zoige wetland were determined through a range of index value distribution, discrimination ability, and correlation analysis of 74 candidate indicators, which included 5 metrics of the number of soil animal individuals, the number of meso/micro soil animal individual, the number of ground spiders, Fungivorous form animal and Saprozoic animal, while plant integrity index including 4 metrics of mesophyte, annuals plant, Gentians, ration of annuals/Perennials. Use the quartile method to determine four grades of undisturbed, mild, moderate, severe disturbance in the study area with 95% quantile of all sampling points as the best-expected value and judge the disturbance status of the Zoige swamp wetland. The results showed that the relatively primary wetland was undisturbance, swamp meadow 2 was mild disturbance, long-term low intensity drainage stress area was moderate disturbance, and short-term high intensity drainage stress area was severe disturbance. Among the investigated typical wetland of Zoige, 20% of wetlands were undisturbance, 30% were mild disturbance, 30% were moderate disturbance, and 20% were the severe disturbance. According to the Pearson correlation coefficient analysis, there was a significantly positive correlation between surface soil animal integrity index and plant communities integrity index (r=0.722, P<0.05), indicating that the evaluation results of surface soil animal integrity index and plant integrity index were consistent.

Dynamics of nutrient release from solid carbon sources of wetland plants and its effect on the efficiency of nitrogen removal from artificial wetland water bodies

污水低碳氮比(C/N)是影响人工湿地氮去除效果限制因素，传统的碳源添加及利用存在成本较高、补充困难的局限性. 本研究契合“就地取材，原位处理”的废物利用原则，选择人工湿地常见的水生植物和农业废弃物(玉米芯、稻草)作为对照，对比了挺水植物(香蒲、美人蕉)、浮叶植物(莲)、沉水植物(菹草)、湿生植物(南荻、短尖苔草)的释碳能力，初步确定了以香蒲、美人蕉、南荻为代表的植物具有较好的释放碳能力，在中国湿地中分布广泛，且均对水体二次污染较小. 以南荻、美人蕉、玉米芯作为碳源添加的模拟人工湿地实验验证表明，在低碳氮比的模拟表流人工湿地投入植物碳源，能有效提高系统的脱氮效率，对照组、南荻组、美人蕉组和玉米芯组的出水总氮浓度分别为(5.24±0.07)、(4.50±0.10)、(3.75±0.17)和(2.97±0.18)mg/L，对应的去除率分别为58%、64%、70%和76%，确定南荻和美人蕉植物残体以及改性材料均残体和改性材料适合作为人工湿地中原位利用的外加碳源. 本研究探索了通过湿地植物配置解决人工湿地水体低C/N比的问题，为提高湿地脱氮效果提供了有意义的新途径.;The low carbon to nitrogen ratio (C/N) of wastewater is a limiting factor of nitrogen removal in artificial wetlands, and traditional carbon sources are costly and difficult to replenish. This study, taking aquatic plants and agricultural wastes (corn cobs and rice straw) which commonly exist in artificial wetlands as a reference, compared the carbon release capacity of water-supporting plants (Typha orientalis and Canna indica), floating-leaf plants (Nelumbo nucifera), submerged plants (Potamogeton crispus), and wet plants (Triarrhena lutarioriparia and Carex brevicuspis). The results show that the plants, such as Typha orientalis, Canna indica and Triarrhena lutarioriparia, which widely distribute in wetlands of China, have high carbon release capacities and have less secondary pollution to water bodies. The experiments of artificial wetlands added with Triarrhena lutarioriparia, Typha orientalis and corn cob as carbon source explored that addition of plant carbon source in the surface flow of artificial wetlands with low C/N ratio could effectively improve the denitrification efficiency of the system. Total nitrogen concentration of the control group, Triarrhena lutarioriparia group, Typha orientalis group and corn cob group were (5.24±0.07), (4.50±0.10), (3.75±0.17) and (2.97±0.18) mg/L, respectively. Correspondingly, the removal rates account for 58%, 64%, 70% and 76%, respectively. It is confirmed that plant residues and modified materials of Triarrhena lutarioriparia and Canna indica were appropriate as an in-situ source of additional carbon in artificial wetlands. Exploring the low C/N ratio in artificial wetlands through wetland plant configuration would provide a new way to improve wetland denitrification.

Roosting-site Selection by Overwintering Black-necked Cranes in the Caohai Wetland, Guizhou Province, China: Implications for Conservation Management.

Stable and high-quality roosting-sites are crucial for the survival of migratory wading birds in winter. The black-necked crane (Grus nigricollis) is the only crane species that lives on the Tibetan plateau for its entire life. Every year, black-necked cranes routinely migrate to the wetlands on the southern lower plateau and roost at wetland sites. Currently, many roosting-sites are under threat from wetland degradation resulting from human disturbance, and changes in water depths and the landscape environment. To understand how the black-necked crane selects roosting-sites given these influencing factors, we conducted a study in the Caohai wetland in China by comparing and modeling the selection of roosting habitat. The vegetation factors mainly included the vegetation height of the swamp patch where the roosting-site was located (VHP) and the vegetation height in the roosting-site (VHR), and the geographic factors mainly included the height of the nearest hill (HNH) and the visible range (VR). These four factors were first considered by the black-necked cranes when choosing roosting-sites on the lakeshore. The roosting-site selection model of black-necked cranes was fitted as (P = e Logit(p) /(1 + e Logit(p)) Logit(p) = 1.243 + 8.397(VHP) -7.999(VHR) -4.105(HNH) + 1.584(VR)). In the Caohai wetland, black-necked cranes preferred roosting-sites away from human disturbances, such as villages/settlements and roads, and where the distance to main roads was > 1,300 m, the distance to villages/residential areas was > 650 m, the distance to rural/service roads was > 500 m, the relatively open area with surrounding hills had a relative height < 15 m, the visible range area was > 550,000 m2, and the shallow swamp area had a water depth of < 5 cm with a vegetation height of < 15 cm. Outside the area of the roosting-site, the surrounding vegetation height was 35 cm-60 cm. We believe that human disturbance, not energy savings or heat loss, was the main factor influencing crane roost site selection. We first gathered data about black-necked crane selection of roosting-sites in a highly complex wetland system. Based on our findings, we strongly recommend appropriately managing the habitat patches in the Caohai wetland, which will have implications for the conservation management of overwintering black-necked cranes in wetlands.

Impact of applying imazapyr on the control of Spartina alterniflora and its eco-environments in the Yellow River Delta, China

• The control of Spartina alterniflora by imazapyr is superior to the physical treatment method in terms of technology, cost, time-consuming and environmental protection. • Both imazapyr itself and its residues are of low risk. • The 25% imazapyr aqueous solution has no toxic effect on benthos. The invasion of Spartina alterniflora has threatened and damaged coastal wetlands in China, therefore, control and removal of this severe invasive plant are urgently needed. Green chemical control is an effective and low-cost method that can be used for large-scale removal of invasive specie. To study the control effect of imazapyr on S. alterniflora and evaluate its impact on other species and the wetland environment, a control experiment was set up in the Yellow River Delta Reserve in Shandong Province in May 2021. A total of 9 treatments were set up in the experiment: 25% (W) imazapyr water (main agent), three treatments with dose gradients of 3.0, 6.0, and 9.0 L/acre, and the main agent at a dose of 6.0 L/acre with six treatments of AGE 809 (adjuvant A) and AGE 852 (adjuvant B) with dose gradients of 1.3, 2.6, and 5.2 L/acre, respectively. The results showed that after 60 days of application, the control efficiency of Spartina alterniflora was over 90%, and the residual amount was small in the plots with the main agent additive<6.0 L/acre. Among them, the residues on leaves were 0.499∼2.822 mg/kg, the residues in soil ranged from 0.0012 to 0.0714 mg/kg, and were from not detected in water to 8.8E-4 mg/kg. During the experiment, there were significant differences in soil physicochemical properties among different treatments, and imazapyr significantly affected on the availability of soil C, N, and P at the stage of large chemical residues ( P < 0.05). In addition, imazapyr was not toxic to the benthic community and increased from 168.72/m 3 to 633.75/m 3 in 60 days after spraying. This study provides a theoretical basis, data support, and technical support for applying herbicides to control S. alterniflora in coastal wetlands of China.

Nitrogen Loss from Anaerobic Ammonium Oxidation Coupled to Iron(Iii) Reduction Activity Across Estuarine and Coastal Wetlands of China: Spatial Variations, Controlling Factors, and Environmental Implications

Nitrogen Loss from Anaerobic Ammonium Oxidation Coupled to Iron(Iii) Reduction Activity Across Estuarine and Coastal Wetlands of China: Spatial Variations, Controlling Factors, and Environmental Implications