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vegetation change as related to terrain factors at two glacier forefronts, Glacier National Park, Montana, U.S.A.

Journal of Mountain Science 2020年第1期17卷 1-15页

作者： Callie B.LAMBERT Lynn M・RESLER Yang SHAO David R.BUTLER Department of Geography Virginia Tech220 Stanger StreetBlacksburgVA24061USA Texas State University Department of GeographySan MarcosTX 78666USA

Glacier recession is a globally occurring trend. Although a rich body of work has documented glacial response to climate warming, few studies have assessed vegetation cover change in recently deglaciated areas, especially using geospatial technologies. Here, vegetation change at two glacier forefronts in Glacier National Park, Montana, *** quantified through remote sensing analysis,fieldwork validation, and statistical ***, we assessed the spatial and temporal patterns of landcover change at the two glacier forefronts in Glacier National Park and determined the role of selected biophysical terrain factors(elevation, slope, aspect, solar radiation, flow accumulation, topographic wetness index, and surficial geology) on vegetation change(from nonvegetated to vegetated cover) at the deglaciated *** imagery of the study locations in 1991, 2003,and 2015 were classified and validated using visual interpretation. Model results revealed geographic differences in biophysical correlates of vegetation change between the study areas, suggesting that terrain variation is a key factor affecting spatialtemporal patterns of vegetation change. At Jackson Glacier forefront, increases in vegetation over some portion or all of the study period were negatively associated with elevation, slope angle, and consolidated bedrock. At Grinnell Glacier forefront,increases in vegetation associated negatively with elevation and positively with solar *** geospatial and field approaches to the study of vegetation change in recently deglaciated terrain are recommended to understand and monitor processes and patterns of ongoing habitat change in rapidly changing mountain environments.

关键词： Land cover change Physical geography Glacial forefronts vegetation change Glacier National Park Terrain factors

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vegetation change of Ecotone in West of Northeast China Plain Using Time-series Remote Sensing Data

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Chinese Geographical Science 2010年第2期20卷 167-175页

作者： HUANG Fang WANG Ping School of Urban and Environmental Sciences Northeast Normal University Changchun 130024 China

Multi-temporal series of satellite SPOT-vegetation normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) data from 1998 to 2007 were used for analyzing vegetation change of the ecotone in the west of the Northeast China Plain. The yearly and monthly maximal values,anomalies and change rates of NDVI and NDWI were calculated to reveal the interannual and seasonal changes in vegetation cover and vegetation water content. Linear regression method was adopted to characterize the trends in vegetation change. The yearly maximal NDVI decreased from 0.41 in 1998 to 0.37 in 2007,implying the decreasing trend of vegetation activity. There was a significant decrease of maximal NDVI in spring and summer over the study period,while an increase trend was observed in autumn. The vegetation-improved regions and vegetation-degraded regions occupied 17.03% and 20.30% of the study area,respectively. The maximal NDWI over growing season dropped by 0.027 in 1998–2007,and about 15.15% of the study area showed a decreasing trend of water content. vegetation water stress in autumn was better than that in spring. vegetation cover and water content variations were sensitive to annual precipitation,autumn precipitation and summer temperature. The vegetation degradation trend in this ecotone might be induced by the warm-drying climate especially continuous spring and summer drought in the recent ten years.

关键词： vegetation change normalized difference vegetation index (NDVI) normalized difference water index (NDWI) SPOT-vegetation ecotone Northeast China Plain

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vegetation change Prediction with Geo-Information Techniques in the Three Gorges Area of China

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Pedosphere 2006年第4期16卷 457-467页

作者： M. T. JABBAR SHI Zhi-Hua WANG Tian-Wei CAI Chong-Fa Huazhong Agriculture University Wuhan 430070 （China）. Department-of Soil and Water College of Agriculture University of Basrah （Iraq）

A computerized parametric methodology was applied to monitor, map, and estimate vegetation change in combination with '3S' (RS-remote sensing, GIS-geographic information systems, and GPS-global positioning system) technology and change detection techniques at a 1:50000 mapping scale in the Letianxi Watershed of western Hubei Province, China. Satellite images (Landsat TM 1997 and Landsat ETM 2002) and thematic maps were used to provide comprehensive views of surface conditions such as vegetation cover and land use change. With ER Mapper and ERDAS software, the normalized difference vegetation index (NDVI) was computed and then classified into six vegetation density classes. ARC/INFO and ArcView software were used along with field observation data by GPS for analysis. Results obtained using spatial analysis methods showed that NDVI was a valuable first cut indicator for vegetation and land use systems. A regression analysis revealed that NDVI explained 94.5% of the variations for vegetation cover in the largest vegetation area, indicating that the relationship between vegetation and NDVI was not a simple linear process. vegetation cover increased in four of areas. This meant 60.9% of land area had very slight to slight vegetation change, while 39.1% had moderate to severe vegetation change. Thus, the study area, in general, was exposed to a high risk of vegetation cover change.

关键词： geo-information techniques vegetation change vegetation indices

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Holocene vegetation change in relation to fire and volcanic events in Jilin, Northeastern China

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Science China Earth Sciences 2015年第8期58卷 1404-1419页

作者： ZHAO HongLi LI XiaoQiang Valerie A.HALL State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Laboratory of Vertebrate Evolution and Human Origins Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of Sciences School of Geography Archaeology and Palaeoecology Queen's University Belfast

Volatiles erupted from large-scale explosive volcanic activities have a significant impact on climate and environmental *** an important ecological factor,the occurrence of fire is affected by vegetation cover,and fire can feed back into both vegetation and climatic *** causes of fire events are diverse;and can include volcanic *** amount of charcoal in sediment sequences is related to the frequency and intensity of fire,and hence under good preservation conditions fire history can be reconstructed from fossil charcoal *** now,little research on the role of fire has been carried out in northeastern *** this study,through research on charcoal and tephra shards from Gushantun and Hanlongwan,Holocene vegetation change in relation to fire and volcanic events in Jilin,Northeastern China,was *** tephra shards are present in Gushantun it is associated with low level of both conifers and broadleaved trees,and is also associated with a pronounced charcoal *** suggests forest cover was greatly reduced from a fire caused by an eruption of the Tianchi *** also detected one tephra layer in Hanlongwan,which also has the almost same depth with low level forest pollen values and one charcoal *** was caused probably by an eruption of the Jinlongdingzi volcano.

关键词： Holocene vegetation change fire history tephra shards volcanic events Northeastern China

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vegetation change and its response to drought in Inner Mongolia of northern China from 1998 to 2013

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Research in Cold and Arid Regions 2019年第6期11卷 448-460页

作者： Shu Lin Liu Tao Wang Wen Ping Kang Zi Chen Guo Xue Qin Zhang Key Laboratory of Desert and Desertification Northwest Institute of Eco-environment and ResourcesChinese Academy of Sciences

vegetation plays a significant role in global terrestrial ecosystems and in combating *** analyzed vegeta tion change in Inner Mongolia of northern China using the Normalized Difference vegetation Index(NDVI)from 1998 to 2013,which is an important composite of Chinese National Ecological Security *** correlation between vegeta tion growth and drought quantified using the Standardized Precipitation Evapotranspiration Index(SPEI)was also ex *** show that vegetation in most of the study area has been rehabilitated to various degrees,especially in re gions such as most of the Horqin Sandy Land,eastern Ordos Plateau,Hetao Plain,as well as the middle-northern Da Hing gan Ling *** improvement in spring was significant in most of the study *** degradation was centrally distributed in Xilingol grassland close to the Sino-Mongolia border and abandoned croplands in Ulanqab *** change trends and seasonal differences varied among different vegetation *** biggest vegetation variation in the growing season was the belt-like distribution along those grasslands close to the precipitation isoline of 200 mm and the Sino-Mongolia border,but also variation in summer and autumn exist in obvious spatial differences be tween grasslands and *** largely influenced vegetation change of Inner Mongolia at 6-month scale or 12-month scale,except for forests of eastern Hunlun Buir Meng and deserts or gobi deserts of western Alxa ***,drought in the previous winter and early spring seasons had a lag effect on growing-season *** grassland was the most easily affected by drought in the study *** activities have made great progress in improving local vegetation under the lasting drought background.

关键词： vegetation change drought SPOT NDVI SPEI Inner Mongolia

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Separating impacts of vegetation change and climate variability on streamflow using hydrological models together with vegetation data

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Science China(Technological Sciences) 2012年第7期55卷 1964-1972页

作者： LI HuiYun ZHANG YongQiang WANG BenDe Nanjing Institute of Geography ＆ Limnology Chinese Academy of Sciences Nanjing 210008 China CSIRO Land and Water GPO BOX 1666 CanberraACT 2601 Australia Faculty of Infrastructure Engineering Dalian University of Technology Dalian 116024 China

vegetation information is seldom considered in lumped conceptual rainfall-runoff *** paper uses two modified rainfall-runoff models,the Xinanjiang-ET and SIMHYD-ET models in which vegetation leaf area index is incorporated,to investigate impacts of vegetation change and climate variability on streamflow in a Southern Australian catchment,the Crawford River experimental catchment,where Tasmanian blue gum plantations were introduced gradually from 1998 till *** Xinanjiang-ET and SIMHYD-ET models incorporate remotely-sensed leaf area index(LAI) data obtained from the Advanced Very High Resolution Radiometer(AVHRR) on board NOAA polar orbiting *** to the original versions,the Xinanjiang-ET and SIMHYD-ET models show marginal improvements in runoff simulations in the pre-plantation period(1882-1997).The calibrated Xinanjaing-ET and SIMHYD-ET models are then used to simulate plantation impact on streamflow in the post-plantation *** total change in streamflow between the pre-plantation and post-plantation periods is 32.4 mm/*** modelling results from the two models show that plantation reduces streamflow by 20.5 mm/a,and climate variability reduces streamflow by 11.9 mm/*** results suggest that increase in plantations can reduce streamflow substantially,even more than climate variability.

关键词： vegetation change climate variability streamflow leaf area index hydrological model Crawford River

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Integrating cross-sensor high spatial resolution satellite images to detect subtle forest vegetation change in the Purple Mountains,a national scenic spot in Nanjing,China

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Journal of Forestry Research 2020年第5期31卷 1743-1758页

作者： Fangyan Zhu Wenjuan Shen Jiaojiao Diao Mingshi Li Guang Zheng College of Forestry Nanjing Forestry UniversityNanjing 210037People’s Republic of China Co-Innovation Center for Sustainable Forestry in Southern China Nanjing Forestry UniversityNanjing 210037People’s Republic of China Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology International Institute for Earth System ScienceNanjing UniversityNanjing 210023People’s Republic of China

Accurate information on the location and magnitude of vegetation change in scenic areas can guide the configuration of tourism facilities and the formulation of vegetation protection *** spatial resolution remote sensing images can be used to detect subtle vegetation *** major objective of this study was to map and quantify forest vegetation changes in a national scenic location,the Purple Mountains of Nanjing,China,using multi-temporal cross-sensor high spatial resolution satellite images to identify the main drivers of the vegetation changes and provide a reference for sustainable *** used Quickbird images acquired in 2004,IKONOS images acquired in 2009,and WorldView2 images acquired in *** pixel-based direct change detection methods including the normalized difference vegetation index difference method,multi-index integrated change analysis(MIICA),principal component analysis,and spectral gradient difference analysis were compared in terms of their change detection ***,the best pixel-based detection method in conjunction with object-oriented image analysis was used to extract subtle forest vegetation *** accuracy assessment using the stratified random sampling points was conducted to evaluate the performance of the change detection *** results showed that the MIICA method was the best pixel-based change detection *** the object-oriented MIICA with an overall accuracy of 0.907 and a kappa coefficient of 0.846 was superior to the pixel-based *** 2004 to 2009,areas of vegetation gain mainly occurred around the periphery of the study area,while areas of vegetation loss were observed in the interior and along the boundary of the study area due to construction activities,which contributed to 79%of the total area of vegetation *** 2009–2015,the greening initiatives around the construction areas increased the forest vegetation coverage,accounting for 84%of the total area of veget

关键词： High spatial resolution satellite images vegetation change Direct detection method Objectoriented Purple Mountains

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Using multispectral landsat and sentinel-2 satellite data to investigate vegetation change at Mount St. Helens since the great volcanic eruption in 1980

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Journal of Mountain Science 2018年第9期15卷 1851-1867页

作者： Katharina TELTSCHER Fabian Ewald FASSNACHT Institute of Geography and Geoecology Karlsruhe Institute of Technology

Long-term analyses of vegetation succession after catastrophic events are of high interest for an improved understanding of succession dynamics. However, in many studies such analyses were restricted to plot-based measurements. Contrarily, spatially continuous observations of succession dynamics over extended areas and timeperiods are sparse. Here, we applied a change vector analysis(CVA) to investigate vegetation succession dynamics at Mount St. Helens after the great volcanic eruption in 1980 using Landsat. We additionally applied a supervised random forest classification using Sentinel-2 data to map the currently prevailing vegetation types. change vector analysis was performed with the normalized difference vegetation index(NDVI) and the urban index(UI) for three subsequent decades after the eruption as well as for the whole observation time between 1984 and 2016. The influence of topography on the current vegetation distribution was examined by comparing altitude, slope angles and aspect values of vegetation classes derived by the random forest classification. WilcoxRank-Sum test was applied to test for significant differences between topographic properties of the vegetation classes inside and outside of the areas affected by the eruption. For the full time period, a total area of 516 km2 was identified as re-vegetated, whereas the area and magnitude of re-growing vegetation decreased during the three decades and migrated closer to the volcanic crater. vegetation losses were mainly observed in regions unaffected by the eruption and related mostly to timber harvesting. The vegetation type classification reached a high overall accuracy of approximately 90%. 36 years after the eruption, coniferous and deciduous trees have established at formerly devastated areas dominating with a proportion of 66%, whereas shrubs are more abundant in riparian zones. Sparse vegetation dominates at regions very close to the crater. Elevation was found to have a great influence on th

关键词： Mount St. Helens vegetation change Remote sensing change vector analysis (CVA) Supervised classification Topography Density-plots

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vegetation change detection using artificial neural networks with ancillary data in Xishuangbanna,Yunnan Province,China

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Science Bulletin 2007年第S2期 232-243页

作者： Lieven VERBEKE Eva De CLERCQ Robert De WULF Laboratory of Forest Management and Spatial Information Ghent UniversityGhent 9000Belgium

Timely and accurate change detection of the Earth's surface features provides the foundation for better planning,management and environmental *** this study ANN change detection was used to perform vegetation change detection,and was compared with post-classification *** the post-classification was performed the ANN classification was used to yield muititemporal vegetation *** were also used to perform a one-pass classification for the images in 2003 and *** and slope were used as two extra *** the training stage,the training data was separated into 82 subclasses including 36 change subclasses and 46 no change *** NDVI dif- ferencing methods were used to develop the change *** result showed that combining the NDVI differencing method with visual interpretation when identifying reference areas can produce more ac- curate change detection results for the ANN one pass change ***,it is effective to use elevation and slope as extra channels together with PCA components,to perform ANN-based change detection in mountainous study *** is also important to separate the vegetation transition classes into subclasses based on spectral response patterns,especially for mountainous *** processing can reduce the topographic effect and improve the change detection accuracy.

关键词： ANN change detection elevation data vegetation change post-classification NDVI differencing

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Palynology in tropical northern Australia: Identifying late Holocene vegetation change in the South Wellesley Islands

Palynology in tropical northern Australia: Identifying late ...

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中国古生物学会孢粉学分会十届一次学术年会

作者： Lydia Mackenzie Patrick Moss Sean Ulm State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences School of Earth and Environmental Science The University of Queensland College of Arts Society and Education James Cook University

This study presents a record of late Holocene environmental change from the South Wellesley Islands in tropical northern Australia. Fossil pollen records from coastal wetlands explored the relationship between humans and the environment, and results from this study provided an environmental context for archaeological research. Archaeological research in the South Wellesley Islands found human occupation occurred only in the last 1,500 years, with sites increasing significantly in the last 700 years. Pollen records found initial changes in the vegetation across the island were driven by late Holocene sea-level regression and coastal progradation, as mangroves transitioning to woodland and wetland communities in the last 850 years. Macroscopic and microscopic charcoal complements the palynological research by identifying the spatial and temporal variation in fire regimes across the island. Results indicate low intensity fires characterised the early human occupation phase. Local and regional fires increased significantly around AD 1950 when Indigenous fire practices were disrupted and the South Wellesley Islands abandoned. In tropical northern Australia many plants are adapted to fire, however the palynological research found only small vegetation changes occurred as fire significantly increased. This study highlights the importance of using multi-proxy approaches to reconstructing past environments, especially where vegetation is adapted to fire.

关键词： Palynology Northern Australia Late Holocene Coastal vegetation change Fire

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