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Effects of Water-table Depth and Soil Moisture on Plant Biomass, Diversity, and Distribution at a Seasonally Flooded wetland of poyang lake, China

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Chinese Geographical Science 2015年第6期25卷 739-756页

作者： XU Xiuli ZHANG Qi TAN Zhiqiang LI Yunliang WANG Xiaolong key laboratory of watershed Geographic Sciences Nanjing Institute of Geography and Limnology Chinese Academy of Sciences University of Chinese Academy of Sciences key laboratory of poyang lake wetland and watershed research Ministry of Education Jiangxi Normal University

Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetland. poyang lake, the largest freshwater lake in China, has been encountering dramatic changes in hydrological conditions in last decade, which greatly influenced the wetland vegetations. To explore the relationships between hydrology and vegetation distri- bution, water-table depth, soil moisture, species composition, diversity and biomass were measured at a seasonally flooded wetland section at Wucheng National Nature Reserve. Three plant communities, Artemisia capillaris, Phragmites australis and Carex cineras- cens communities, were examined which are zonally distributed from upland to lakeshore with decreasing elevation. Canonical corre- spondence analysis （CCA）, spearmen correlation and logistic regression were adopted to analyze the relationships between vegetation characteristics and hydrological variables of water-table depth and soil moisture. Results show that significant hydrological gradient exist along the wetland transect. Water-table demonstrates a seasonal variation and is consistently deepest in A. capillaris community （ranging from q）.5 m above ground to ＋10.3 m below ground）, intermediate in P. australis community （-2.6 m to ＋7.8 m） and shallow- est in C. cinerascens community （-4.5 m to ＋6.1 m）. Soil moisture is lowest and most variable in A. capillaris community, highest and least variable in P. australis community, and intermediate and moderate variable in C. cinerascens community. The CCA ordination indicated that variables of water-table depth and soil moisture are strongly related to community distribution, which explained 81.7% of the vegetation variations. Species diversity indices are significantly positively correlated with soil moisture and negatively correlated with moisture variability, while above- and belowground biomass are positively correlated with moisture. Above- and belowground biomass presen

关键词： water-table depth soil moisture species diversity biomass Gaussian model poyang lake wetland

Atmospheric correction of HJ-1A/B CCD images over Chinese coastal waters using MODIS-Terra aerosol data

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Science China(Technological Sciences) 2010年第S1期53卷 191-195页

作者： TIAN LiQiao 1,LU JianZhong 1,CHEN XiaoLing 1,2,3,YU ZhiFeng 1,XIAO JingJing 1,QIU Feng 1 & ZHAO Xi 1 1 State key laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University,Wuhan 430079,China 2key laboratory of poyang lake wetland and watershed research,ministry of education,Jiangxi Normal University,Nanchang 330022,China 3 The key laboratory of poyang lake Environment and Resource Utilization,ministry of education,Nanchang University,Nanchang 330031,China State key laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan China key laboratory of poyang lake wetland and watershed research Ministry of Education Jiangxi Normal University Nanchang China The key laboratory of poyang lake Environment and Resource Utilization Ministry of Education Nanchang University Nanchang China

This paper demonstrates an atmospheric correction method to process HJ-1A/B CCD images over Chinese coastal waters with the aid of MODIS-Terra aerosol *** on the assumption of zero water-leaving radiance at the two near-infrared (NIR)bands or the shortwave infrared(SWIR)bands,the atmospheric aerosol optical depth(AOD)is firstly retrieved from MODIS-Terra with a simple extension of the NIR-SWIR combined atmospheric correction approach embedded in SeaDAS (SeaWiFS data analysis system).Then the"turbid"and"non-turbid"waters are separated by the turbid water *** probability of AOD at 551 nm band is derived based on the NIR information over"non-turbid"waters and FLAASH model is selected to do the atmospheric correction of the HJ-1A/B CCD imagery using the AOD values of highest probabilities as ***,according to the histogram of the AOD distribution at 551 nm band,the studied turbid water area is divided into several blocks and HJ-1A/B CCD imagery is corrected with the corresponding AOD values displayed with the highest frequency in each *** method has been applied to several HJ-1A/B images over Chinese coastal waters and validated by synchronous in-situ *** results have shown that this method is effective in the atmospheric correction process of HJ-1A/B CCD images for ocean color remote sensing study and application in the coastal waters.

关键词： ocean color remote sensing atmospheric correction turbid coastal waters HJ-1A/B MODIS

Spatial and Temporal Change of Habitat Quality of poyang lake Basin in China at Small watershed Scale and Its Multidimensional Response to Landscape Pattern

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Chinese Geographical Science 2023年第3期33卷 565-582页

作者： BI Manyu ZHONG Yexi XIAO Zeping FENG Xinghua MA Hongzhi School of Geography and Environment Jiangxi Normal UniversityNanchang 330022China key laboratory of poyang lake wetland and watershed research ministry of education(Jiangxi Normal University) Nanchang 330022China

The health and function of ecosystems are largely determined by the quality of habitat,and the optimal regulation of landscape patterns has become an important way to improve regional habitat *** article takes the poyang lake Basin of China as a case,reveals the spatial and temporal change of its habitat quality at the small watershed scale,and attempts to examine the multidimensional response of habitat quality to landscape pattern changes with respect to landscape compositions and landscape *** results show:1)from 2000 to 2020,the overall landscape fragmentation of the basin decreased,the landscape aggregation in the central small watersheds changed significantly,and the spatial distribution of landscape elements in the central and southern small watersheds were relatively homogeneous.2)The overall habitat quality of the poyang lake Basin is at a middle to high level,with significant spatial differentiation,showing the distribution characteristics of‘high in the periphery,low in the center,high in the south and low in the north’.3)Both landscape compositions and landscape configurations influenced habitat quality,but there were obvious differences in the response *** the landscape composition and configuration dimension,the influence of landscape composition on habitat quality was greater than that of landscape configuration;from the multilevel landscape configuration dimension,compared to landscape level,landscape configuration at the class level impacted habitat quality more *** the end,this article proposes a differentiated regulation strategy for habitat quality conservation in small watersheds from the perspective of landscape patterns to improve the ecological service level of poyang lake Basin.

关键词： landscape watershed Spatial

Atmospheric correction of ocean color imagery over turbid coastal waters using active and passive remote sensing

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Chinese Journal of Oceanology and Limnology 2009年第1期27卷 124-128页

作者：田礼乔陈晓玲张亭禄龚威陈莉琼陆建忠赵羲张伟于之锋 State key laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University The key Lab. of poyang lake Environment and Resource Utilization Ministry of Education Nanchang University The key laboratory of poyang lake wetland and watershed research Ministry of Education Jiangxi Normal University laboratory of Ocean Remote Sensing Ministry of Education Ocean Remote Sensing Institute Ocean University of China

This paper demonstrates an atmospheric correction method to process MODIS/Aqua (Moderate-resolution Imaging Spectroradiometer) ocean color imagery over turbid coastal waters with the aid of concurrent CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization) aerosol data, assuming that there exists "nonturbid" water in the study area where MODIS aerosol optical properties can be retrieved accurately. Aerosol properties from CALIOP measurements were obtained and related to those from MODIS. This relationship, combined with CALIOP aerosol data, was extended to turbid water to derive MODIS aerosol properties, where atmospheric correction using MODIS data alone often fails. By combining MODIS and CALIOP data, aerosol signals were separated from the total signals at the satellite level, and water-leaving radiances in turbid waters were subsequently derived. This method was tested on several MODIS/Aqua ocean color images over South China turbid waters. Comparison with field data shows that this method was effective in reducing the errors in the retrieved water-leaving radiance values to some extent. In the Zhujiang (Pearl) River Estuary, this method did not overestimate the aerosol effects as severely, and provided far fewer negative water-leaving radiance values than the NASA (National Aeronautics and Space Administration) default methods that used MODIS data alone.

关键词： Ocean color remote sensing atmospheric correction turbid coastal waters CALIOP MODIS

Sensitivity of Near Real-time MODIS Gross Primary Productivity in Terrestrial Forests Based on Eddy Covariance Measurements

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Chinese Geographical Science 2015年第5期25卷 537-548页

作者： TANG Xuguang LI Hengpeng LIU Guihua LI Xinyan YAO Li XIE Jing CHANG Shouzhi key laboratory of watershed Geographic Sciences Nanjing Institute of Geography and Limnology Chinese Academy of Sciences key laboratory of poyang lake wetland and watershed research (Jiangxi Normal University) Ministry of Education Department of Geography University of Zurich Jilin University College of Geo Exploration Science and Technology

As an important product of Moderate Resolution Imaging Spectroradiometer(MODIS), MOD17A2 provides dramatic improvements in our ability to accurately and continuously monitor global terrestrial primary production, which is also significant in effort to advance scientific research and eco-environmental management. Over the past decades, forests have moderated climate change by sequestrating about one-quarter of the carbon emitted by human activities through fossil fuels burning and land use/land cover change. Thus, the carbon uptake by forests reduces the rate at which carbon accumulates in the atmosphere. However, the sensitivity of near real-time MODIS gross primary productivity(GPP) product is directly constrained by uncertainties in the modeling process, especially in complicated forest ecosystems. Although there have been plenty of studies to verify MODIS GPP with ground-based measurements using the eddy covariance(EC) technique, few have comprehensively validated the performance of MODIS estimates(Collection 5) across diverse forest types. Therefore, the present study examined the degree of correspondence between MODIS-derived GPP and EC-measured GPP at seasonal and interannual time scales for the main forest ecosystems, including evergreen broadleaf forest(EBF), evergreen needleleaf forest(ENF), deciduous broadleaf forest(DBF), and mixed forest(MF) relying on 16 flux towers with a total of 68 site-year datasets. Overall, site-specific evaluation of multi-year mean annual GPP estimates indicates that the current MOD17A2 product works highly effectively for MF and DBF, moderately effectively for ENF, and ineffectively for EBF. Except for tropical forest, MODIS estimates could capture the broad trends of GPP at 8-day time scale for all other sites surveyed. On the annual time scale, the best performance was observed in MF, followed by ENF, DBF, and EBF. Trend analyses also revealed the poor performance of MODIS GPP product in EBF and DBF. Thus, improvements in the

关键词： MOD 17A2 FLUXNET community eddy covariance (EC) gross primary productivity (GPP) forest ecosystem evaluation

Colonization–competition dynamics of basal species shape food web complexity in island metacommunities

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Marine Life Science & Technology 2023年第2期5卷 169-177页

作者： Guanming Guo Fei Zhao Ivan Nijs Jinbao Liao ministry of education’s key laboratory of poyang lake wetland and watershed research School of Geography and EnvironmentJiangxi Normal UniversityNanchang 330022China research Group in Plants and Ecosystems Department of BiologyUniversity of Antwerp2610 WilrijkBelgium

Exploring how food web complexity emerges and evolves in island ecosystems remains a major challenge in *** webs assembled from multiple islands are commonly recognized as highly complex trophic networks that are dynamic in both space and *** the context of global climate change,it remains unclear whether food web complexity will decrease in a monotonic fashion when undergoing habitat destruction(e.g.,the inundation of islands due to sea-level rise).Here,we develop a simple yet comprehensive patch-dynamic framework for complex food web metacommunities subject to the competition-colonization tradeof between basal *** found that oscillations in food web topological complexity(characterized by species diversity,mean food chain length and the degree of omnivory)emerge along the habitat destruction *** outcome is robust to changing parameters or relaxing the assumption of a strict competitive *** oscillations in food web complexity indicates that small habitat changes could have disproportionate negative efects on species diversity,thus the success of conservation actions should be evaluated not only on changes in biodiversity,but also on system robustness to habitat ***,this study provides a parsimonious mechanistic explanation for the emergence of food web complexity in island ecosystems,further enriching our understanding of metacommunity assembly.

关键词： Competition-colonization tradeof Food web complexity Hierarchical competition Patch-dynamic framework Patch loss

Analysis of chaotic climatic process in the Tarim River Basin (I)

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research in Cold and Arid Regions 2019年第5期11卷 340-349页

作者： ZuHan Liu key laboratory of the education ministry for poyang lake wetland and watershed research Jiangxi Normal University Jiangxi Province key laboratory for Water Information Cooperative Sensing and Intelligent Processing Nanchang Institute of Technology

Based on observational data obtained from 1961 to 2011 in the Tarim River Basin,China,we investigated the chaotic dynamics of temperature,precipitation,relative humidity,and *** main findings are as follow:(1)The four data series have significant chaotic and fractal behaviors,which are the result of the evolution of a nonlinear chaotic dynamic *** climatic process in the Tarim River Basin also has deterministic and stochastic characteristics.(2)To describe the temperature,precipitation,relative humidity,and evaporation dynamics,at least three independent variables at daily scale are required;in terms of complexity,their order is evaporation>temperature>precipitation>relative humidity.(3)Their respective largest Lyapunov exponentλ1 shows the order of their degree of complexity is relative humidity>temperature>precipitation≈evaporation;the maximum time scales for which the four systems can be predicted are 17 days,17 days,16 days,and 16 days,if calculated separately.(4)The Kolmogorov entropy K illustrates that the complexity of the nonlinear precipitation system is much greater than that of the other three *** temperature and evaporation systems exhibit weaker chaotic behavior,their predictability is better,and the degree of complexity is less than that of the other two factors.

关键词： chaos climatic process largest Lyapunov exponent Kolmogorov entropy correlation dimension

Spatial heterogeneity of dead fuel moisture content in a Larix gmelinii forest in Inner Mongolia using geostatistics

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Journal of Forestry research 2021年第2期32卷 569-577页

作者： Heng Zhang Shihao Ma Ping Kang Qiuliang Zhang Zhiwei Wu Forestry College of Inner Mongolia Agricultural UniversityHohhot 010019People’s Republic of China key laboratory of poyang lake wetland and watershed research Ministry of EducationJiangxi Normal UniversityNanchang 330022People’s Republic of China

Spatial heterogeneity of fuel moisture content determines the spread rate and direction of a forest *** on the spatial heterogeneity of the moisture content of dead fuel of Larix gmelinii *** that:(1)fuel moisture con... 详细信息

关键词： Forest combustibles Spatial heterogeneity Analog sampling Standard error

Assessment of total suspended sediment concentrations in poyang lake using HJ-1A/1B CCD imagery

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Chinese Journal of Oceanology and Limnology 2012年第2期30卷 295-304页

作者：于之锋陈晓玲周斌田礼乔袁小红冯炼 State key laboratory of Information Engineering in Surveying Mapping and Remote Sensing(LIESMARS)Wuhan University Institute of Remote Sensing and Earth Sciences Hangzhou Normal University Zhejiang Provincial key laboratory of Urban wetlands and Regional Change key laboratory of poyang lake wetland and watershed research Ministry of EducationJiangxi Normal University

We explored the potential of the environment and disaster monitoring and forecasting small satellite constellations (HJ-1A/1B satellites) charge-coupled device (CCD) imagery (spatial resolution of 30 m, revisit time of 2 days) in the monitoring of total suspended sediment (TSS) concentrations in dynamic water bodies using poyang lake, the largest freshwater lake in China, as an example. Field surveys conducted during October 17-26, 2009 showed a wide range of TSS concentration (3-524 mg/L). Atmospheric correction was implemented using the Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) module in ENVI with the aid of aerosol information retrieved from concurrent Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) surveys, which worked well at the CCD bands with relatively high reflectance. A practical exponential retrieval algorithm was created between satellite remote sensing reflectance and in-situ measured TSS concentration. The retrieved results for the whole water area matched the in-situ data well at most stations. The retrieval errors may be related to the problem of scale matching and mixed pixel. In three selected subregions of poyang lake, the distribution trend of retrieved TSS was consistent with that of the field investigation. It was shown that HJ-1A/1B CCD imagery can be used to estimate TSS concentrations in poyang lake over synoptic scales after applying an appropriate atmospheric correction method and retrieval algorithm.

关键词： total suspended sediment HJ-1A/1B CCD atmospheric correction retrieval algorithm poyang lake