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1.
近50年来富锦湿地景观遥感与GIS的时空动态分析   总被引:3,自引:0,他引:3  
湿地是重要的自然资源,但是由于自然和人为影响,湿地正在大面积的萎缩,导致功能和效益下降,并危及到区域的持续发展。本文以三江平原挠力河流域富锦(市)作为研究区域,以RS、GIS和Fragstats为技术手段,分析了自1954年以来沼泽湿地的空间和时间退缩过程及其驱动力,重建了自1954年以来的土地利用/土地覆被变化过程。结果表明,湿地面积由1954年的519.917.96hm2下降到105.008hm2,由占总面积的61.27%下降到12.39%,仅是原来面积的17.74%;而耕地面积由223 173.54hm2增加到597 156.25hm2,由占总面积的25.31%增加到70.45%。同时指,出人类的农垦活动是富锦沼泽湿地面积退缩的主要原因。  相似文献   

2.
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.  相似文献   

3.
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.  相似文献   

4.
Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 for Bao′an station, from 1955 to 2009 for Baoqing station, from 1956 to 2009 for Caizuizi station and from 1978 to 2009 for Hongqiling station. The influences of climate change and human activities on runoff change were investigated, and the causes of hydrological regime change were revealed. The seasonal runoff distribution of the Naoli River was extremely uneven, and the annual change was great. Overall, the annual runoff showed a significant decreasing trend. The annual runoff of Bao′an, Baoqing, and Caizuizi stations in 2009 decreased by 64.1%, 76.3%, and 84.3%, respectively, compared with their beginning data recorded. The wet and dry years of the Naoli River have changed in the study period. The frequency of wet year occurrence decreased and lasted longer, whereas that of dry year occurrence increased. The frequency of dry year occurrence increased from 25.0%-27.8% to 83.9%-87.5%. The years before the 1970s were mostly wet, whereas those after the 1970s were mostly dry. Precipitation reduction and land use changes contributed to the decrease in annual runoff. Rising temperature and water project construction have also contributed important effects on the runoff change of the Naoli River.  相似文献   

5.
1 INTRODUCTION The Ussuri / Wusuli River watershed is located in the southeast part of Heilongjiang Province of China, which joins remote regions of Russia. The watershed consists of approximately 26 000 000 ha, which is about two thirds of the watershed ecosystem in Russia, one  third in China. The Ussuri River forms part of the border between Russia and China, the shared border stretches more than 1100 km. Khanka/Xingkai Lake lies within both China and Russia. Its total area …  相似文献   

6.
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.  相似文献   

7.
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.  相似文献   

8.
Accurate wetland delineation is the basis of wetland definition and mapping, and is of great importance for wetland management and research. The Zoigê Plateau on the Qinghai-Tibet Plateau was used as a research site for research on alpine wetland delineation. Several studies have analyzed the spatiotemporal pattern and dynamics of these alpine wetlands, but none have addressed the issues of wetland boundaries. The objective of this work was to discriminate the upper boundaries of alpine wetlands by coupling ecological methods and satellite observations. The combination of Landsat 8 images and supervised classification was an effective method for rapid identification of alpine wetlands in the Zoigê Plateau. Wet meadow was relatively stable compared with hydric soils and wetland hydrology and could be used as a primary indicator for discriminating the upper boundaries of alpine wetlands. A slope of less than 4.5° could be used as the threshold value for wetland delineation. The normalized difference vegetation index(NDVI) in 434 field sites showed that a threshold value of 0.3 could distinguish grasslands from emergent marsh and wet meadow in September. The median normalized difference water index(NDWI) of emergent marsh remained more stable than that of wet meadow and grasslands during the period from September until July of the following year. The index of mean density in wet meadow zones was higher than the emergent and upland zones. Over twice the number of species occurred in the wet meadow zone compared with the emergent zone, and close to the value of upland zone. Alpine wetlands in the three reserves in 2014 covered 1175.19 km2 with a classification accuracy of 75.6%. The combination of ecological methods and remote sensing technology will play an important role in wetland delineation at medium and small scales. The correct differentiation between wet meadow and grasslands is the key to improving the accuracy of future wetland delineation.  相似文献   

9.
黄河三角洲人类干扰活动强度变化及其景观格局响应   总被引:1,自引:0,他引:1  
本研究以湿地变化较为剧烈的黄河三角洲为研究对象,基于RS技术和GIS空间分析方法,利用人为干扰度模型,结合区域人工沟渠建设情况,从区域和局地两个尺度直观揭示人类干扰强度时空分异特征,并探究区域景观格局对人类干扰活动的响应,以期为黄河三角洲滨海湿地生态保护与人类活动调控提供决策支持。结果表明:① 1995-2015年现代黄河三角洲区域人为干扰度和人工沟渠密度均明显增加,空间分布呈现从西南部向东部、北部,自内陆向沿海的扩展趋势;② 随着人类活动强度增强,研究区自然湿地面积减少,区域景观多样性和空间异质性增加,景观整体连通性减弱,景观复杂性降低;③ 景观格局对人类干扰强度变化的响应关系呈现出地区和时间差异;人类干扰活动强度相对较低的保护区受人工沟渠建设的影响,也呈现出斑块团聚程度降低、景观多样性增加和景观复杂性降低的变化趋势;④ 人为干扰度指数和人工沟渠密度指标互为补充,互相印证,可以较为全面、客观地反映黄河三角洲地区人类干扰活动强度。  相似文献   

10.
Zoige Wetland is one of the largest plateau wetlands in the world. This paper provides a dynamic analysis of spatial and temporal patterns of the wetland in Zoige, Eastern Qinghai-Tibetan Plateau, supported by ERDAS8.7 and ArcGIS9.0. It is the first comparative analysis of a system of rapidly changing wetland with landscape patterns in Zoige, using 3 classified landsat Thematic Mapper images of 1977, 1994 and 2001. The classified images were used to generate wetland distributing maps, and shape index (S), diversity index (H), dominance index (D), evenness index (E), fragmentation index (F) and fractal dimension (Fd) were calculated and analyzed spatiotemporally across pure grazing area in Zoige for each landscape type and in different periods (before 1977, during 1977-1994 and 1994-2001), as well as the driving forces of natural and anthropogenic. The study shows that for a comprehensive understanding of the shapes and trajectories of the shrinking and desertificated land expansion of the wetland, a spatiotemporal landscape metrics analysis in different periods is an improvement than only with landscape changing rates. This type of analysis can also be used to infer underlying social, economic, and political processes that drive the observed wetland forms. The results indicate that wetland patterns can be changed over relatively short periods of time. The total area of lake reduced by 164.86 km^2, grassland extended by 141.74 km^2, semi-marsh extended by 105.94 km^2, marsh reduced by 86.00 km^2 the number of landscape patches reduced by 56, and their average area decreased by 2.68 km^2, the successions within lake, marsh, semi-marsh and grassland were found obviously. S decreased stepwise: D and F increased but H decreased: The changing rate after 1994 was 2.3 to 2.9 times greater than that before. The change of the wetland landscape patterns resulted in the interaction between socio-ceenomic and natural forces of positive and negative aspects; and natural factors affected as assistant aspect. Some important human activities in this period led to the change of the landscape patterns in this region directly. Some measurements made by government and NGO delayed the converting process partly.  相似文献   

11.
本文通过对湿地景观的时空动态发展过程其形成空间格局的分析,构建了基于ANN-CA的银川平原湿地景观时空模拟模型,并对湿地景观格局过程与主要驱动力因子间的响应关系进行了情景模拟。研究结果表明:年降水量对天然湿地中的河流湿地和湖泊湿地的驱动作用呈正相关关系,对水稻田和坑塘湿地的影响不显著;人口密度对人工湿地的驱动作用呈正相关,随着人口密度的增加,水稻田和坑塘向各个方向大面积蔓延,河流和湖泊等天然湿地的面积则逐渐减少;随着农业生产活动的加强、农业总产值的增加,河流和湖泊缓慢减少,水稻田和坑塘等人工湿地分布迅速扩张。  相似文献   

12.
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.  相似文献   

13.
三江平原挠力河上游流域水文过程及其驱动力模型研究   总被引:1,自引:0,他引:1  
以三江平原挠力河上游流域为研究对象,选择年均流量和洪峰流量两个水文参变量,对流域降水、耕地面积和各水文参变量的统计回归分析,分别建立水文过程的单因素模型,用于分析气候变化、土地利用变化对水文过程的影响。在定量区分土地利用变化和气候变化的水文效应基础上,利用最小二乘法建立基于降雨量和耕地面积两种因素的流域水文过程驱动力模型。研究结果表明:(1)1956-1975年间降雨量对水文过程的影响非常显著,之后影响逐渐降低,总体上为气候模型对年均流量的模拟能力高于洪峰流量;(2)流域耕地面积,自1954年以来不断扩张,但未对水文过程产生显著影响,对洪峰流量的影响高于对年均径流的影响;(3)研究区的水文过程驱动力模型的模拟效果较好,相比单因素模型,年均流量和洪峰流量的模拟精度均得到较大提高,RMSE分别为0.5和1.04;对年均流量的模拟精度更高一些,决定性系数为0.933;(4)总体上,研究区水文过程受气候变化的影响程度高于土地利用变化,但土地利用变化对水文过程的影响不容忽视,尤其是对洪峰流量的影响呈增大趋势。  相似文献   

14.
The Yellow River Delta wetland is the youngest wetland ecosystem in China's warm temperate zone. To better understand how its landscape pattern has changed over time and the underlying factors responsible, this study analyzed the dynamic changes of wetlands using five Landsat series of images, namely MSS(Mulri Spectral Scanner), TM(Thematic Mapper), and OLI(Operational Land Imager) sensors in 1976, 1986, 1996, 2006, and 2016. Object-oriented classification and the combination of spatial and spectral features and both the Normalized Difference Vegetation Index(NDVI) and Normalized Difference Water Index(NDWI), as well as brightness characteristic indices, were used to classify the images in eCognition software. Landscape pattern changes in the Yellow River Delta over the past 40 years were then delineated using transition matrix and landscape index methods. Results show that: 1) from1976 to 2016, the total area of wetlands in the study area decreased from 2594.76 to 2491.79 km~2, while that of natural wetlands decreased by 954.03 km~2 whereas human-made wetlands increased by 851.06 km~2. 2) The transformation of natural wetlands was extensive: 31.34% of those covered by Suaeda heteropteras were transformed into reservoirs and ponds, and 24.71% with Phragmites australis coverage were transformed into dry farmland. Some human-made wetlands were transformed into non-wetlands types: 1.55% of reservoirs and ponds became construction land, and likewise 21.27% were transformed into dry farmland. 3) From 1976 to 2016, as the intensity of human activities increased, the number of landscape types in the study area continuously increased. Patches were scattered and more fragmented. The whole landscape became more complex. In short, over the past 40 years, the wetlands of the Yellow River Delta have been degraded, with the area of natural wetlands substantially reduced. Human activities were the dominant forces driving these changes in the Yellow River Delta.  相似文献   

15.
闽江口湿地遥感时空演变应用分析   总被引:6,自引:0,他引:6  
将闽江口湿地动态变化度、湿地变化转移矩阵和景观生态学的空间格局模型相结合,横、纵向分析了1986- 1994年、1994-2000年两个时期闽江口湿地的动态演变模式。研究表明,在两个时期不同的社会政策和经济发展阶段,人类活动对闽江口湿地的干扰强度与对象不同,造成两个时期不同的湿地演变模式。在1986-1994年间景观类型动态变化,以水田面积的扩张为主导,在1994-2000年间景观类型动态变化突出表现为城乡建筑用地对水田、非湿地农业的占用。在1986-2000年间,湿地景观中,人工水域破碎度增加,破碎化速度提高,形状更加复杂化;水田破碎度和形状复杂度都由增加向减弱转变;天然水域破碎度减小,形状复杂程度由减少变为增加;滩地破碎度由减少变为增加,形状复杂化由增加转向减少。在中、小时间尺度范围内,人类活动是影响闽江口湿地演变的主要原因之一,特别是近10多年来社会经济的高速发展,城镇化进程的加速,人类活动成为影响闽江口湿地的最主要原因。  相似文献   

16.
为了了解黄河三角洲湿地景观类型演变最优模拟模型以及景观的变化趋势,本文采用1996、2006、2016年3期黄河三角洲分类影像,分别利用CA-Markov、LCM、2种模型叠加开展变化模拟。研究发现:① 在相同驱动力因子影响下,空间模拟上LCM比CA-Markov好,数量模拟上,CA-Markov比LCM更贴合,对于变化较大研究区,综合2种模型优势来模拟该湿地变化最佳;② 对于较强的人为、自然灾害干扰,会对模拟精度有影响。在LCM模型中,驱动力相同情况下,生成适宜性图像的转移子模型数量越多,模拟精度越高。对于CA-Markov模型,比例误差系数适宜的设置对数量模拟的精度也有提升;③ 在保持2006-2016年的变化趋势下,综合2种模型模拟的2026年自然湿地面积1252.69 km 2,人工湿地面积1265.00 km 2,非湿地面积924.51 km 2。从2026年黄河三角洲模拟的结果可看出,自然、非湿地的面积减少,人工湿地大量的增加并不断向浅海区域扩张。通过对黄河三角洲湿地变化进行预测分析,可为湿地资源的合理有效利用与管理等提供科学依据。  相似文献   

17.
以珠穆朗玛峰国家自然保护区为研究区域,选取2009年23幅MODIS NDVI影像,采用傅里叶变换的HA-NTS算法去除云干扰,并重构NDVI时间序列图像.(1)根据研究区沼泽湿地与其他地物类型物候特征的差异,利用光谱角制图方法(SAM)获取了研究区2009年沼泽湿地的分布图.研究区沼泽湿地共有2 481.13km2,...  相似文献   

18.
Wetlands play an important ecological role and provide many functions for people,yet wetlands are cur-rently decreasing and deteriorating.The ability to calculate an economic value for the loss of wetlands is becoming in-creasingly important for policy makers.In this study,remote sensing,field investigations,department visits,and other methods were used to survey wetland types,assess wetland area changes,and calculate wetland economic value.Mar-ket value loss and ecological function value loss,caused by reduction of wetland area and environmental pollution were calculated using commonly accepted methods of market valuation,ecological valuation,environmental protection investment cost analysis,and outcome parameters.According to market value loss and ecological function value loss,preliminarily fund allocation for wetland and ecological compensation was calculated.This will provide an important reference for future Yellow River Delta eco-compensation studies.  相似文献   

19.
The wetlands on the Zoige Plateau have experienced serious degradation, with most of the original marsh being converted to marsh meadow or meadow. Based on the 3 wetland degradation stages, we determined the effects of wetland degradation on the structure and relative abundance of nitrogen-cycling (nitrogen-fixing, ammonia-oxidizing, and denitrifying) microbial communities in 3 soil types (intact wetland: marsh soil; early degrading wetland: marsh meadow soil; and degraded wetland: meadow soil) using 454-pyrosequencing. The structure and relative abundance of nitrogen-cycling microbial communities differed in the 3 soil types. Proteobacteria was the predominant phylum in most soil samples but the most abundant soil nitrogen-fixing and denitrifying microbial bacteria differed at the class, order, family, and genus levels among the 3 soil types. At the genus level, the majority of nitrogen-fixing bacterium sequences related to Bradyrhizobium were from marsh and marsh meadow soils; whereas those related to Geobacter originated from meadow soil. The majority of ammonia-oxidizing bacterium sequences related to Nitrosospira were from marsh (except for the 40-60 cm layer), marsh meadow and meadow soils; whereas those related to Candidatus Solibacter originated from 40-60 cm layer of marsh soil. The majority of denitrifying bacterium sequences related to Candidatus Solibacter and Anaeromyxobacter were from marsh and meadow soils; whereas those related to Herbaspirillum originated from meadow soil. The distribution of operational taxonomic units (OTUs) and species were correlated with soil type based upon Venn and Principal Coordinates Analysis (PCoA). Changes in soil type, caused by different water regimes were the most important factors influencing compositional changes in the nitrogen-fixing, ammonia-oxidizing, and denitrifying microbial communities.  相似文献   

20.
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。  相似文献   

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