Evolution characteristics of hydrological connectivity pattern of marsh wetland in Naoli River Basin

As an important indicator of the structural and functional stability of wetland landscapes, hydrological connectivity plays an important role in maintaining the stability of wetland ecosystems. Large-scale human activities have led to significant changes in the hydrological connectivity pattern of wetlands in Naoli River Basin since 1950 s. Combined with the availability of wetland habitat and the spreading capacity of aquatic birds, hydrological connectivity indices of marsh wetlands were calculated in the studied area, and the temporal and spatial changes were analyzed from 1950 s to 2015. The results indicate that:(1) the hydrological connectivity index of the marsh wetlands shows a growth trend with increasing distance threshold. All patches of marsh wetlands linked together when the distance threshold reached 35--40 km;(2) the optimal distance of hydrological connectivity is about 10 km for marsh wetlands of whole Naoli River Basin;(3) the total hydrological connectivity of marsh wetlands decreased in the Naoli River Basin from 1950 s to 2015. Although the hydrological connectivity index increased after 2005, the fragmentation of the landscape has not been improved. The analysis of the wetland hydrological connectivity can provide a scientific basis for the ecological restoration and protection of the wetland in the Naoli River Basin.     

Wetland resource protection and rational utilization in China

Wetlands of China cover an area of 63 million ha, among which, natural wetlands 25 million ha, including mires, shallow lakes, etc., artificial wetlands 38 million ha. Besides these, there are a lot of rivers and islands, stretching 18,000 km of coastal line and coastal zone below the tidal within the water depth of 6 m. Based on the climatic regional differences, biota similarity and biodiversity abundance, China’s wetlands can be divided into 9 main regions. Wetlands not only have huge functions to regulate mankind’s living environment, but also are the important and precious natural resources. For a long period, since the contradiction between population and resources, energy, grain is getting more and more obvious, China’s wetlands are facing to serious disturbances, such as large-scale reclamation, overhunting, industrial waste water pollution and species introducing. They have brought about the wetland quantity reducing and quality falling, furthermore have effects on sustainable development. For the special national conditions of China, higher population pressure, China should carry out wetland resource protection and rational utilization, not only protection.     

CONSTRAINING FACTORS TO SUSTAINABLE UTILIZATION OF WATER RESOURCES AND THEIR COUNTERMEASURES IN CHINA

This paper discusses the constraining factors to sustainable utilization of water resources in China,and the countermeasures to realize sustainable water utilization.The result of comprehensive analysis shows that constraining factors to sustainable utilization of water resources in China are complicated, including physical geographi cal factors and socio-economic factors, such as uneven distribution of water resources at temporal and spatial scales,inappropriate institutional arrangement and non-water-saving and non-water-conservation production and life mode.The countermeasures against constraining factors to water resources sustainable development are put forward as follows: l) using wetlands and forests, and through spatial conversion to realize temporally sustainable supply of water resources; 2) transferring water between basins and areas and developing various water resources in water shortagearea; 3) establishing water-saving society; 4) strengthening water pollution control and water resources protection;and 5) establishing unified water resources management mechanism.     

Valuation of lake and marsh wetlands ecosystem services in China

Wetlands are highly productive natural ecosystems, providing valuable goods and services. There is growing interest in transferring ecosystem service value from the existing wetlands studied to other wetlands ecosystems at a large geographic scale. The benefit transfer method uses the known values from wetlands to predict the value of other wetland sites. This methodology requires only limited time and resources. The present study calculated the value of the ecological services provided by lake and marsh wetlands in China in terms of biodiversity indices, water quality indices and economic indices. Basic data on wetlands were obtained through remote sensing images. The results show that: 1) The total ecosystem service value of the lake and marsh wetlands in 2008 was calculated to be 8.1841 × 1010 United States Dollars(USD), with the marsh and lake wetlands contributing 5.6329 × 1010 and 2.5512 × 1010 USD, respectively. Values of marsh ecosystem service were concentrated in Heilongjiang Province(2.5516 × 1010 USD), Qinghai Province(1.2014 × 1010 USD), and Inner Mongolia Autonomous Region(1.1884 × 1010 USD). The value of the lakes were concentrated in Tibet Autonomous Region(6.223 × 109 USD), Heilongjiang(5.810 × 109 USD), and Qinghai(5.500 × 109 USD). 2) Waste treatment and climate regulation services contributed to 26.29% and 24.74% respectively, of the total ecosystem service value of the marsh wetlands. Hydrological regulation and waste treatment contributed to 41.39% and 32.75%, respectively, of the total ecosystem service value of the lake wetlands. 3) The total ecological service value of the lake and marsh wetlands was 54.64% of the total service value of natural grassland ecosystems and 30.34% of the total service value of forests ecosystems in China.     

塔里木河下游生态环境变化时序监测与对比分析

塔里木河下游地区是我国西部干旱区生态环境问题比较突出的区域。本文主要从地表水(湖泊、河流和湿地)、地下水、地表植被覆盖的角度,基于多源遥感和长时间序列数据,监测和分析生态输水前后区域环境变化和生态响应。首先,采用基于知识迁移的专题图斑更新技术,实现了1990、1995、2000、2005、2010和2015年区域湿地遥感制图和植被覆盖度等生态因子指标提取;然后,以2000年为基准（生态输水起始年）,结合地下水位观测数据,对比分析了人工生态输水前后区域生态环境动态变化过程。结果显示：① 生态输水前（1990-2000年）,塔河下游的生态环境持续恶化,流域范围内一半以上的沼泽湿地消失、河道干涸,地下水位下降,区域植被覆盖大幅度下降;② 生态输水后（2000-2017年）,区域生态环境明显好转,改变了下游河道长期断流状态,区域地下水位明显抬升,地表水域（湖泊和沼泽）面积呈现“V”型逆转增加,区域植被覆盖区和覆盖度均呈现显著增加趋势,曾经一度干涸的塔河尾闾台特玛湖水域面积2017年8月达到147.87 km²。以上研究结果综合表明人工生态输水工程对塔河下游生态环境拯救和治理发挥了重要作用,遏制了生态输水前塔河下游生态环境继续恶化局面,流域生态环境正在逐步恢复。     

Wetlands in China: Feature, value and protection

The estimated total area of wetland in China is more than 25.9 million hectares including about 11.9 million hectares of marshes and bogs, 9.1 million hectares of lake and about 2.2 million hectares of coastal salt marshes and mudflats. The area of wetland is equivalent to 2.7% of the land surface. China also has 2.7 million hectares of shallow sea water (less 5m in depth at low tide). Marshes and bogs are equivalent 1.3% of the land surface. Only three provinces (regions)—Qinghai, Xizang (Tibet) and Heilongjiang — have a larger total area of marsh and bog. According to the structure, type and development of wetland in different river basins, wetland can be classified nine main regions. The experiments indicate that the coefficient of the marsh to regulate flood is similar to that of lakes. Wetlands occupy 17.8% of the Sanjiang Plain area, the annual carbon contribution is 0.78 × 10⁴t. Carbon released from marsh soil return into atmosphere is 3.95 × 10⁶t/a. At present there is a sharp contradiction between population growth and natural resources shortage, causing wetland to be exerted with huge pressures and serious threats. Foundation item: Under the auspices of the Key B Item of the Chinese Academy of Sciences (KZ951-B1-201-02). Biography: LU Xian-guo (1957 —), male, a native of Changchun City, Jilin Provice, professor. His research interests include wetland process and environmental effect.     

基于SAR影像后向散射特性的中俄黑龙江流域洪水监测

黑龙江（又称为阿穆尔河）是中国和俄罗斯之间的国际界河,近年来洪水事件频发,给流域内中俄两国带来巨大的人口伤亡和经济损失,加强该流域的洪水监测是两国面临的共同紧迫需求。传统的光学遥感影像受制于洪水期间多云多雨的天气状况,难以及时获得无云影像。本文充分利用全天候雷达数据的优势,提出了一种基于哨兵1号（Sentinel-1）合成孔径雷达数据监测大面积区域洪水的方法。通过Gamma分布和高斯分布拟合SAR影像后向散射系数的概率密度分布,迭代后验概率差值,自动获得全局阈值来分割初始的水体,基于辅助数据细化去除了初始水体中与水体相似的误分类型,并由形态学操作后处理提高了提取的洪水的均匀性。结果表明：① 与传统的分割算法相比,本文提出的方法基于SAR影像后向散射系数的分布规律进行概率密度函数分段拟合,将全局统计划分为局部关系,显著地改善了常规分割算法在水体和非水体像素量级相差过大而表现不佳的情况;② 研究获得了2017—2020年逐年的洪水分布,结果总体精度在87.78%~94.89%之间,Kappa系数在0.76~0.89之间;③ 特别是对于大面积半干旱地区,本文结合了后向散射特性、地形和其他辅助信息的关系,使得能够有效地保留水体并去除与水体后向散射系数相似的地物;④ 结果显示黑龙江（阿穆尔河）中下游沿岸城市哈巴罗夫斯克、阿穆尔斯克等地区为经常性泛洪区域,洪水面积整体呈增加趋势。研究表明,基于雷达数据对洪水空间范围进行时间序列监测,可以为中俄黑龙江流域洪水发展动态监测提供科学支撑。     

Landscape pattern evolution processes of alpine wetlands and their driving factors in the Zoige Plateau of China

Zoige Plateau wetlands are located in the northeastern corner of the Qinghai-Tibet Plateau.The landscape pattern evolution processes in the Zoige Plateau and their driving factors were identified by analyzing the dynamic changes in landscape modification and conversion and their dynamic rates of alpine wetlands over the past four decades.The results showed that the landscape conversion between wetlands and non-wetlands mainly occurred during the period from 1966 to 1986.The marsh wetland area converted from lake and river wetlands was larger because of swamping compared to other wetland landscapes.Meanwhile,the larger area of marsh wetlands was also converted to lake wetlands more than other types of wetlands.The modification processes mainly occurred among natural wetland landscapes in the first three periods.Obvious conversions were observed between wetland and nonwetland landscapes(i.e.,forestland,grassland,and other landscapes) in the Zoige Plateau.These natural wetland landscapes such as river,lake and marsh wetlands showed a net loss over the past four decades,whereas artificial wetland landscapes(i.e.,paddy field and reservoir and pond wetlands) showed a net decrease.The annual dynamic rate of the whole wetland landscape was 0.72%,in which the annual dynamic rate of river wetlands was the highest,followed by lake wetlands,while marsh wetlands had the lowest dynamic rate.The integrated landscape dynamic rate showed a decreasing trend in the first three periods.The changes in wetland landscape patterns were comprehensively controlled by natural factors and human activities,especially human activities play an important role in changing wetland landscape patterns.     

Combined influence of sedimentation and vegetation on the soil carbon stocks of a coastal wetland in the Changjiang estuary

Coastal wetlands play an important role in the global carbon cycle.Large quantities of sediment deposited in the Changjiang(Yangtze) estuary by the Changjiang River promote the propagation of coastal wetlands,the expansion of saltmarsh vegetation,and carbon sequestration.In this study,using the Chongming Dongtan Wetland in the Changjiang estuary as the study area,the spatial and temporal distribution of soil organic carbon(SOC) stocks and the influences of sedimentation and vegetation on the SOC stocks of the coastal wetland were examined in 2013.There was sediment accretion in the northern and middle areas of the wetland and in the Phragmites australis marsh in the southern area,and sediment erosion in the Scirpus mariqueter marsh and the bare mudflat in the southern area.More SOC accumulated in sediments of the vegetated marsh than in the bare mudflat.The total organic carbon(TOC) stocks increased in the above-ground biomass from spring to autumn and decreased in winter;in the below-ground biomass,they gradually increased from spring to winter.The TOC stocks were higher in the below-ground biomass than in the above-ground biomass in the P.australis and Spartina altemiflora marshes,but were lower in the below-ground biomass in S.mariqueter marsh.Stocks of SOC showed temporal variation and increased gradually in all transects from spring to winter.The SOC stocks tended to decrease from the high marsh down to the bare mudflat along the three transects in the order:P.australis marsh S.alterniflora marsh S.mariqueter marsh bare mudflat.The SOC stocks of the same vegetation type were higher in the northern and middle transects than in the southern transect.These results suggest that interactions between sedimentation and vegetation regulate the SOC stocks in the coastal wetland in the Changjiang estuary.     

Variations of dissolved iron in the Amur River during an extreme flood event in 2013

As a key factor limiting primary productivity in marine ecosystem, dissolved iron(DFe) export from fluvial systems has increased recently. There is particular concern about discharges of DFe during extreme flooding, when they are thought to increase considerably. An extreme flood event that caused inundation of extensive areas of Far Eastern Russia and Northeastern China occurred in the basin of the Amur River during summer and autumn 2013. During this event, water samples were collected in the middle reaches of the Amur River and the lower reaches at Khabarovsk City and analyzed for DFe concentrations and other aquatic parameters. The results show that the average DFe concentrations in the middle reaches of the Amur River(right bank) and at Khabarovsk were 1.11 mg/L and 0.32 mg/L, respectively, during the extreme flood in 2013. The total discharge of DFe during the flood event was 6.25 × 104 t. The high discharge of DFe during the flood reflects the elevated discharge of the river, hydrologically connected riparian wetlands, vast quantities of terrestrial runoff, and flood discharges from the Zeya and Bureya reservoirs. These results show that long-term monitoring is needed to identify and assess the impacts of DFe transport on the downstream reaches, estuarine area, and coastal ecosystems of the Amur River.     

Spatial and Temporal Changes of Wetlands on the Qinghai-Tibetan Plateau from the 1970s to 2010s

Wetlands on the Qinghai-Tibetan Plateau (QTP) perform a dazzling array of vital ecological functions and are one of the most fragile ecosystems in the world. Timely and accurate information describing wetland resources and their changes over time is becoming more important in their protection and conservation. By using remote sensing data, this study intended to investigate spatial distribution and temporal variations of wetlands on the QTP at different watershed scales from 1970s to 2010s. Results show that wetlands on the QTP have undergone widespread degradation from 1970s to 2010s, with nearly 6.4% of their area being lost. Areas of freshwater marsh, salt marsh and wet meadow declined by 46.6%, 53.9% and 15.6%, respectively, while lake area increased by 14.6%. The most extensive losses of natural wetlands have occurred in endorheic basins, such as in the Kunlun-Altun-Qilian Drainage Basin and Qiangtang Basin, which shrank by 44.5% and 33.1%, respectively. A pronounced increase in temperature tends to facilitate the evaporation process and reduce water availability for wetlands. One-third of the wetlands on the QTP are under threat of being submerged due to lakes rising in recent years. More research is needed to gain insight into the interaction mechanisms behind observed variations and potential impacts from further warming in the future.     

Early Cretaceous flora from coal-bearing strata of Markovsky Peninsula in South Primorye，Russia

The Early Cretaceous flora from the coal-bearing strata(Ussuri and Lipovtsy formations)in the Markovsky peninsula of South Primorye,Far East Russia,is reported in some detail in this paper.The flora containing over 80 species of about 50 genera can be divided into two assemblages.The paleofloristic characteristics and the comparisons of this flora with its coeval floras from the adjacent region of the eastern Heilongjiang of Northeast China,indicate the flora and its coal-bearing strata of the Markovsky peninsula can be compared to those of the Chengzihe and Muling formations of the Jixi area of Heilongjiang,representing probably the late Barremian and Aptian age,respectively.     

Spatial variations in depth-distribution of trace metals in coastal wetland sediments from Quanzhou Bay, Fujian Province, China

Four short cores were obtained from the coastal wetland of the Quanzhou Bay, Fujian Province, China, and sediment samples were analyzed with a Mastersizer 2000 for grain size analysis and an Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) for trace metal analysis. The results of grain size analysis show that the wetland sediments are mainly composed of silt and clay, and the distribution of median grain size is affected by human activities obviously. The results of trace metal analysis show that the wetland sediments mainly originate from terrestrial materials in the Luoyangjiang River estuary and from contaminants discharged from adjacent rivers in Shuitou area. The heavy metal contamination in Luoyangjiang estuary decreased from 1984 to 2004 due to industry transformation, but has increased since 2004 because of the discharge of contaminants to the Jinjiang River and much living sewerage to the bay, and a large number of trace metals are trapped within Spartina alterniflora marsh.     

Review of Rapid Transformation of Floodplain Wetlands in Northeast China: Roles of Human Development and Global Environmental Change

Northeast China is the region with the largest area of wetlands in China. The Sanjiang Plain and the Songnen Plain are large freshwater marsh distribution regions that are affected by climate warming and by the increasing frequency and density of extreme weather and are the regions most subject to disturbances by human activities in Northeast China. The wetlands of the Sanjiang Plain and the Songnen Plain have shrunk severely in the past 60 years, and wetland functions have been reduced substantially because of climate change, unreasonable land use, fire episodes, engineering and construction works and urbanization. Large-scale agricultural development started in the 1950s has been the most important driving factor for wetland loss and degradation in the Sanjiang Plain. Water shortage has been the most important factor for degradation and fragmentation of wetlands in the Songnen Plain. To mitigate wetland degradation and better protect wetlands, special regulations, long-term mechanisms and technical support of wetland protection should be established. A wetland compensation program should be implemented, and technologies for increasing the adaptive capacity of wetlands should be developed. Moreover, it is most important to find the balanced threshold between agricultural development and wetland protection.     

MIKE BASIN支持下的流域水文建模与水资源管理分析——以西藏达孜县为例

基于ArcView GIS平台,利用流域水资源规划管理软件工具MIKE BASIN,以西藏达孜县为试验区,采用50×50m格网DEM数据,开展拉萨河流域内的地表水的产汇计算,并进行流域水资源合理配置研究。本文建立了流域供需水的空间分析网络,对各汇流区进行流域模拟分析,研究结果以直观的专题图表显示,为本区的流域水资源管理提供了可视化的研究框架。     

EFFECTS OF AGRICULTURE RECLAMATION ON THE HYDROLOGIC CHARACTERISTICS IN THE SANJIANG PLAIN, CHINA

1 THE NATURAL ENVIRONMENTAL CHARACTERISTICS The Sanjiang Plain is located in the northeast of Heilongjiang Province, China. Russia borders this region in the north and east. Its total area is 1.088×107ha. The area of plain occupies 61.21％of the total land area and that of hill and mountain amounts to 38.79％of the total land area. It is not only one of the most important regions with large area of fresh water wetlands and with varieties of rare migratory waterfowls, but a…     

SNOW COVER MONITORING BY REMOTE SENSING AND SNOWMELT RUNOFF CALCULATION IN THE UPPER HUANGHE RIVER BASIN

The upper Huanghe(Yellow) River basin is situated in the northeast of the Qinghai-Xizang(Tibet)Plateau of China.The melt-water from the snow-cover is main water supply for the rivers in the region during springtime and other arid regions of the northwestern China, and the hydrological conditions of the rivers are directly controlled by the snowmelt water in spring .So snowmelt runoff forecast has importance for hydropower,flood prevention and water resources utilize-tion.The application of remote sensing and Geographic Information System(GIS) techniques in snow cover monitoring and snowmelt runoff calculation in the upper Huanghe River basin are introduced amply in this paper.The key parame-ter-snow cover area can be computed by satellite images from multi-platform,multi-templral and multi-spectral.A clus-ter of snow-cover data can be yielded by means of the classification filter method.Meanwhile GIS will provide relevant information for obtaining the parameters and also for zoning .According to the typical samples extracting snow covered moun-tained in detail also.The runoff snowmelt models based on the snow-cover data from NOAA images and observation data of runoff,precipitation and air temperature have been satisfactorily used for predicting the inflow to the Longyangxia Reser-voir,which is located at lower end of snow cover region and is one of the largest reservoirs on the upper Huanghe River, during late March to early June.The result shows that remote sensing techniques combined with the ground meteorological and hydrological observation is of great potential in snowmelt runoff forecasting for a large river basin.With the develop-ment of remote sensing technique and the progress of the interpretation method,the forecast accuracy of snowmelt runoff will be improved in the near future .Large scale extent and few stations are two objective reality situations in Chian,so they should be considered in simulation and forecast.Apart from dividing ,the derivation of snow cover area from satellite images would decide the results of calculating runoff.Field investigation for selection of the learning samples of different snow patterns is basis for the classification.     

Is There Any Correlation Between Landscape Characteristics and Total Nitrogen in Wetlands Receiving Agricultural Drainages?

In the case of increasing fragmentation of wetlands, the study of the relationship between wetland landscape characteristics and total nitrogen(TN) in water is of great significance to reveal the mechanism of wetland water purification. Taking the Naoli River(NR) wetlands in Northeast China as the research object, 10 uniformly distributed sampling sites in the study area were sampled in August 2015 to test the TN concentration and interpret the images of NR wetlands in the same period. Taking the sampling site as the control point, the whole wetlands were divided into 10 regions, and the landscape index of each region was extracted. In order to reveal whether the landscape characteristics are related to the TN concentration in the wetlands water body, the landscape index and the TN concentration in the control point water body were analyzed by correlation analysis, step-by-step elimination analysis and path analysis to reveal whether the landscape characteristics are related to the TN concentration under wetlands receiving agricultural drainages. The results showed that the correlation coefficients between four area indexes or eight shape indexes and TN concentration did not reach a significant correlation level(P > 0.05), indicating that TN removal was not only determined by a single landscape index. The path coefficient of edge density(ED) index is –0.41, indicating that wetland patch connectivity is the primary factor of TN removal, and there is no relationship between the larger patch area and the higher TN removal. The removal of TN in wetlands is restricted by the synergistic effect of landscape area and shape characteristics.     

AN ANALYSIS OF WATER RESOURCE CHARACTERISTICS OF THE RIVERS IN THE NORTHERN SLOPE OF THE KUNLUN MOUNTAINS

ＡＮＡＮＡＬＹＳＩＳＯＦＷＡＴＥＲＲＥＳＯＵＲＣＥＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＴＨＥＲＩＶＥＲＳＩＮＴＨＥＮＯＲＴＨＥＲＮＳＬＯＰＥＯＦＴＨＥＫＵＮＬＵＮＭＯＵＮＴＡＩＮＳＸｕＹｏｕｐｅｎｇ（许有鹏）；ＧａｏＹｕｎｊｕｅ（高蕴珏）（Ｄｅｐａｒｔ...     

RESPONSES OF WETLAND ECO-SECURITY TO LAND USE CHANGE IN WESTERN JILIN PROVINCE, CHINA

1IN TR O D U C TIO NEco-security is the state in w hich the resources,envi-ronm entand ecosystem s thatconcern people are secure(M Aetal.,2004;SH Ietal.,2004).O therw ise,w e calliteco-security problem or ecologicalrisk.The eco-se-curity isdraw ing the in…