Tesi sul tema "Vegetation series"
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1
Wahrman, Spencer A. "Time Series Analysis of Vegetation Change using Hyperspectral and Multispectral Data". Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/17473.
Abstract (sommario):
Approved for public release; distribution is unlimitedGrand Lake, Colorado has experienced a severe mountain pine beetle outbreak over the past twenty years. The aim of this study was to map lodgepole pine mortality and health decline due to mountain pine beetle. Multispectral data spanning a five-year period from 2006 to 2011 were used to assess the progression from live, green trees to dead, gray-brown trees. IKONOS data from 2011 were corrected to reflectance and validated against an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) hyperspectral dataset, also collected during 2011. These data were used along with additional reflectance-corrected multispectral datasets (IKONOS from 2007 and QuickBird from 2006 and 2009) to create vegetation classification maps using both library spectra and regions of interest. Two sets of classification maps were produced using Mixture-Tuned Matched Filtering. The results were assessed visually and mathematically. Through visual inspection of the classification maps, increasing lodgepole pine mortality over time was observed. The results were quantified using confusion matrices comparing the classification results of the AVIRIS classified data and the IKONOS and QuickBird classified data. The comparison showed that change could be seen over time, but due to the short time period of the data the change was not as significant as expected.
2
Julien, Yves. "Vegetation monitoring through retrieval of NDVI and LST time series from historical databases". Doctoral thesis, Universitat de València, 2008. http://hdl.handle.net/10803/10343.
Abstract (sommario):
The PhD dissertation presented here falls into the Earth Observation field, specifically vegetation monitoring. This work consists in the extensive exploitation of historical databases of satellite images for vegetation monitoring through two parameters, which are the land surface temperature (LST) and a vegetation index (NDVI). Up to now, vegetation monitoring has been limited to the use of vegetation indices, so the addition of the land surface temperature parameter represents the main innovative character of this PhD study.This dissertation is divided into 5 chapters. The first chapter begins by introducing the theoretical aspects of NDVI and LST parameters, addressing the means for retrieving them from remotely sensed observations, as well as their main limitations. Then, an introduction to vegetal physiology is developed, which allows for understanding how NDVI and LST parameters are linked to plants. A bibliographical study is then presented, which stresses out the gaps in the exploitation of historical databases.The second describes the data used in this PhD. The instrument providing most of these data is embarked on the NOAA (National Oceanic and Atmospheric Administration) satellite series. This instrument is the AVHRR (Advanced Very High Resolution Radiometer). The AVHRR databases used in this work are the PAL (Pathfinder AVHRR Land) and GIMMS (Global Inventory Modeling and Mapping Studies) databases. Additional data used punctually are also described briefly.The third chapter describes the operations applied to the data to prepare their temporal analysis. These operations start with the calculations of vegetation index and land surface temperature parameters. The AVHRR data used in this work are contaminated by the orbital drift of NOAA satellites, so an important part of this doctorate consisted in developing a technique for correcting this effect. We chose to develop our own technique, which we validated by direct comparison with data retrieved by geostationary satellites.In the fourth chapter, the different methods used for data temporal analysis are presented. Those methods consist of trend detection, harmonic analysis, and fitting the temporal series to annual NDVI evolution curves. Then, a phenological analysis is presented, which allows for retrieval of trends in spring and autumn dates for most of the globe. These trends are validated by comparison with previous studies. The trend analysis for spring dates is then extended to the 1948-2006 period using air temperature data. The long-term observation of different NDVI indicators also allows for the detection of land vegetation changes, even in our case of coarse spatial resolution. Finally, two methods for NDVI temporal analysis are compared.In the fifth chapter, a quick presentation of simultaneous study of NDVI and LST is developed through a revision of previous results, followed by the observations carried out from the orbital drift corrected data. These observations allowed for the determination of indicators of NDVI and LST, thus enabling for the characterization of the vegetation at global scale. A harmonic analysis of NDVI and LST at European scale is also presented. The application of the developed indicators for simultaneous monitoring of NDVI and LST shows promising results.As a conclusion, the main results described above are summarized, and plans for a close future are presented. This PhD has also demonstrated that such work could be carried out in a small structure with limited resources.El trabajo de tesis doctoral aquí presentado consiste en el uso extensivo de bases de datos históricas de imágenes de satélite para el seguimiento de la vegetación terrestre, a través de dos parámetros; la temperatura de la superficie terrestre (LST por sus siglas en inglés) y el índice de vegetación NDVI.El primer capítulo de la memoria introduce las nociones de NDVI y LST desde una perspectiva teórica, así como sus principales limitaciones y sus vínculos con la fisiología vegetal. Un estudio bibliográfico permite poner el acento sobre las lagunas en el uso de las bases de datos históricas.El segundo capítulo describe los datos utilizados en este trabajo, proporcionados en su mayoría por el instrumento AVHRR (Advanced Very High Resolution Radiometer) a bordo de la serie de satélites de la NOAA (National Oceanic and Atmospheric Administration) a través de las bases de datos PAL (Pathfinder AVHRR Land) y GIMMS (Global Inventory Modeling and Mapping Studies). También se presentan datos adicionales que se usaron puntualmente. El tercer capítulo describe el proceso para obtener las series temporales de NDVI y LST, las cuales están contaminadas por la deriva orbital de los satélites NOAA. Hemos propuesto una técnica propia para su corrección, validada por comparación directa con datos obtenidos por satélites geoestacionarios.En el cuarto capítulo se introducen diferentes métodos utilizados para el análisis temporal de los datos. Se obtuvieron tendencias acerca de parámetros vinculados a la evolución anual de NDVI para la mayor parte del globo, validadas por comparación con estudios previos.En el quinto capítulo se presenta un análisis conjunto del NDVI y de la LST, seguido por la elaboración de indicadores de la evolución anual de estos dos parámetros. A continuación se presenta un análisis armónico del NDVI y de la LST para Europa. El uso de los indicadores desarrollados para el seguimiento simultáneo del NDVI y de la LST revela resultados prometedores.Por último se presentan las conclusiones más relevantes del trabajo realizado, así como planes de trabajo para un futuro próximo.
3
Julien, Yves Rodriguez Sobrino José Antonio Nerry Françoise. "Vegetation monitoring through retrieval of NDVI and LST time series from historical databases". Strasbourg : Université Louis Pasteur, 2008. http://eprints-scd-ulp.u-strasbg.fr:8080/1021/01/JULIEN_Yves_2008.pdf.
Abstract (sommario):
Thèse de doctorat : Electronique, électrotechnique, automatique : Strasbourg 1 : 2008. Tesis doctoral : Electrónica, electrotécnica, automático : Universitat de València : 2008.Thèse soutenue sur un ensemble de travaux. Thèse soutenue en co-tutelle. Titre provenant de l'écran-titre. Bibliogr. 34 p.
4
Ratana, Piyachat. "Spatial and Temporal Amazon Vegetation Dynamics and Phenology Using Time Series Satellite Data". Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/194427.
Abstract (sommario):
Improved knowledge of landscape seasonal variations and phenology at the regional scale is needed for carbon and water flux studies, and biogeochemical, hydrological, and climate models. Amazon vegetation mechanisms and dynamics controlling biosphere-atmosphere interactions are not entirely understood. To better understand these processes, vegetation photosynthetic activity and canopy water and temperature dynamics were analyzed over various types of vegetation in Amazon using satellite data from the Terra-Moderate Resolution Imaging Spectroradiometer (MODIS). The objectives of this dissertation were to 1) assess the spatial and temporal variations of satellite data over the Amazon as a function of vegetation physiognomies for monitoring and discrimination, 2) investigate seasonal vegetation photosynthetic activity and phenology across the forest-cerrado ecotone and conversion areas, and 3) investigate seasonal variations of satellite-based canopy water and land surface temperature in relation to photosynthetic activity over the Amazon basin.The results of this study showed the highly diverse and complex cerrado biome and associated cerrado conversions could be monitored and analyzed with MODIS vegetation index (VI) time series data. The MODIS enhanced vegetation index (EVI) seasonal profiles were found useful in characterizing the spatial and temporal variability in landscape phenology across a climatic gradient of rainfall and sunlight conditions through the rainforest-cerrado ecotone. Significant trends in landscape phenology were observed across the different biomes with strong seasonal shifts resulting from differences in vegetation physiognomic responses to rainfall and sunlight. We also found unique seasonal and temporal patterns of the land surface water index (LSWI) and land surface temperature (LST), which in combination with the EVI provided improved information for monitoring the seasonal ecosystem dynamics of the Amazon rainforest, cerrado, ecotone, and conversion areas. In conclusion, satellite-based, regional scale studies were found to aid in understanding land surface processes and mechanisms at the ecosystem level, providing a "big picture" of landscape dynamics. Coupling this with ground, in-situ measurements, such as from flux towers, can greatly improve the estimation of carbon and water fluxes, and our understanding of the biogeochemistry and climate in very dynamic and changing landscapes.
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Gebrehiwot, Worku Zewdie. "Climate, land use and vegetation trends". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-209668.
Abstract (sommario):
Land use / land cover (LULC) change assessment is getting more consideration by global environmental change studies as land use change is exposing dryland environments for transitions and higher rates of resource depletion. The semiarid regions of northwestern Ethiopia are not different as land use transition is the major problem of the region. However, there is no satisfactory study to quantify the change process of the region up to now. Hence, spatiotemporal change analysis is vital for understanding and identification of major threats and solicit solutions for sustainable management of the ecosystem. LULC change studies focus on understanding the patterns, processes and dynamics of land use transitions and driving forces of change. The change processes in dryland ecosystems can be either seasonal, gradual or abrupt changes of random or systematic change processes that result in a pattern or permanent transition in land use. Identification of these processes of change and their type supports adoption of monitoring options and indicate possible measures to be taken to safeguard this dynamic ecosystem.
This study examines the spatiotemporal patterns of LULC change, temporal trends in climate variables and the insights of the communities on change patterns of ecosystems. Landsat imagery, MODIS NDVI, CRU temperature, TAMSAT rainfall and socio-ecological field data were used in order to identify change processes. LULC transformation was monitored using support vector machine (SVM) algorithm. A cross-tabulation matrix assessment was implemented in order to assess the total change of land use categories based on net change and swap change. In addition, the pattern of change was identified based on expected gain and loss under a random process of gain and loss, respectively. Breaks For Additive Seasonal and Trend (BFAST) analysis was employed for determining the time, direction and magnitude of seasonal, abrupt and trend changes within the time series datasets. In addition, Man Kendall test statistic and Sen’s slope estimator were used for assessing long term trends on detrended time series data components. Distributed lag (DL) model was also adopted in order to determine the time lag response of vegetation to the current and past rainfall distribution.
Over the study period of 1972- 2014, there is a significant change in LULC as evidenced by a significant increase in size of cropland of about 53% and a net loss of over 61% of woodland area. The period 2000-2014 has shown a sharp increase of cropland and a sharp decline of woodland areas. Proximate causes include agricultural expansion and excessive wood harvesting; and underlying causes of demographic factor, economic factors and policy contributed the most to an overuse of existing natural resources. In both the observed and expected proportion of random process of change and of systematic changes, woodland has shown the highest loss compared to other land use types. The observed transition and expected transition under random process of gain of woodland to cropland is 1.7%, implies that cropland systematically gains to replace woodland. The comparison of the difference between observed and expected loss under random process of loss also showed that when woodland loses cropland systematically replaces it. The assessment of magnitude and time of breakpoints on climate data and NDVI showed different results. Accordingly, NDVI analysis demonstrated the existence of breakpoints that are statistically significant on the seasonal and long term trends. There is a positive trend, but no breakpoints on the long term precipitation data during the study period. The maximum temperature also showed a positive trend with two breakpoints which are not statistically significant. On the other hand, there is no seasonal and trend breakpoints in minimum temperature, though there is an overall positive trend along the study period.
The Man-Kendall test statistic for long term average Tmin and Tmax showed significant variation where as there is no significant trend within the long term rainfall distribution. The lag regression between NDVI and precipitation indicated a lag of up to forty days. This proves that the vegetation growth in this area is not primarily determined by the current precipitation rather with the previous forty days rainfall. The combined analysis showed declining vegetation productivity and a loss of vegetation cover that contributed for an easy movement of dust clouds during the dry period of the year. This affects the land condition of the region, resulting in long term degradation of the environment
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Tomás, Ana Raquel Dias. "Application of empirical mode decomposition (EMD) to chronological series of active fires from MODIS satellite". Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4481.
Abstract (sommario):
Mestrado em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de AgronomiaFire is a global phenomenon, acting as an important disturbance process. Africa is one of the continents that has higher fire density, particularly in savanna regions, making it the subject of innumerous studies about fire regime and behavior. Here, a new method of time series analysis called Empirical Mode Decomposition (EMD) was applied to monthly fire counts time series from MODIS Terra/Aqua sensors. The goals were to analyze the differences between the time series from the two instruments (MODIS Terra and Aqua), the differences in the behavior of the active fire time series from the north and south parts of Africa and they‟re relationships with climatic modes (ENSO and IOD). For most of the time series, the application of the EMD resulted in four IMF‟s and a residue. Although there is always an IMF related with seasonality, the physical meaning of the other isn‟t clear. This may be due to various reasons, some related with intrinsic problems of the method, other with the applicability of the method to this type of series.
7
Casady, Grant M. "Examining Drivers of Post-Wildfire Vegetation Dynamics Across Multiple Scales Using Time-Series Remote Sensing". Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195408.
Abstract (sommario):
Ecosystem response to disturbance is a function of environmental factors interacting at a number of spatio-temporal scales. This research explored ecosystem response to wildfire as a function of local and broad-scale environmental factors using satellite based time-series remote sensing data. This topic was explored as a series of three independent but related studies. The first study focused on the evaluation of techniques for the analysis of time-series satellite data for describing post-fire vegetation trends at sites in the US, Spain, and Israel. Time-series data effectively described post-fire trends, and reference sites were valuable for differentiating between post-fire effects and other environmental factors. The use of phenological indicators derived from the time-series shows promise as a monitoring tool, but requires further investigation. The next study evaluated the influence of broad-scale climate factors on rates of post-fire vegetation regeneration across the western US. Rates of post-fire regeneration were higher with increased precipitation and higher minimum temperatures. Changes in climate are likely to result in shifts in post-fire vegetation dynamics, leading to important feedbacks into the climate system. The use of time-series data was a valuable tool in measuring trends in post-fire vegetation across a large area and over an extended period. The final study used time-series vegetation data to measure variations in post-fire vegetation response across an extensive 2002 wildfire. Regression tree analysis related post-fire regeneration to local environmental factors such as burn severity, soil properties, vegetation, and topography. Residuals from modeled rates of post-fire regeneration were evaluated in the context of management activities and site characteristics using expert knowledge. Post-fire rates of regeneration were a function of water availability, pre-burn vegetation, and burn severity. Management activities, soil differences, and shifts in vegetation community composition resulted in deviations from the modeled post-fire regeneration rates. The results of these three research studies indicate that remotely sensed time-series vegetation data provide a useful tool for measuring post-fire vegetation dynamics. Both broad-scale and local environmental factors play important roles in defining post-fire vegetation response, and the use of remote sensing and geospatial data sets can be useful in integrating these factors and enhancing management decisions.
8
González, Garcia Isabel. "Influência do clima nas variações estacionais e interanuais do indice de vegetação de diferença normalizada (NDVI) no montado português". Master's thesis, ISA/UTL, 2012. http://hdl.handle.net/10400.5/5467.
Abstract (sommario):
Mestrado em Engenharia do Ambiente - Instituto Superior de AgronomiaNowadays the climate change makes more necessary the study of ecosystem dynamics. The Portuguese montado is an ecosystem with very particular characteristics, because is a combined system with pastures and forest, managed by men, and depends on this manage to continue. More than economic value, montado is very important system with a big biodiversity and landscape quality. For this study was propose to study about the seasonal variation of montado, since 2000 to 2012, using remote sensing and vegetation index as tools to analyze the response of montado to different environmental factors, as the precipitation, temperature and relative humidity. The chosen vegetation index was the NDVI (Normalized Difference Vegetation Index), because of all the advantages, and was calculated using MODIS sensor data. To find the relation between our vegetation index vegetation data, and the meteorological variables, was make a time series analysis, and a correlation study of each variable with the vegetation index. The results was satisfactory and was agree with the initial hypotheses. We find that the precipitation is the variable that influences NDVI the most, and this correlation is bigger when we use the accumulative inter-annual and seasonal data instead the original data. The results show the effects of the big drought of 2004 and 2005 too. The remote sensing appears as a very important and critical tool for this study area future and show that this study could be extend with new directions and new research hypotheses
9
Wessollek, Christine, Babatunde Osunmadewa e Pierre Karrasch. "Introducing a rain-adjusted vegetation index (RAVI) for improvement of long-term trend analyses in vegetation dynamics". SPIE, 2015. https://tud.qucosa.de/id/qucosa%3A35057.
Abstract (sommario):
It seems to be obvious that precipitation has a major impact on greening during the rainy season in semi-arid regions. First results1 imply a strong dependence of NDVI on rainfall. Therefore it will be necessary to consider specific rainfall events besides the known ordinary annual cycle. Based on this fundamental idea, the paper will introduce the development of a rain adjusted vegetation index (RAVI). The index is based on the enhancement of the well-known normalized difference vegetation index (NDVI2) by means of TAMSAT rainfall data and includes a 3-step procedure of determining RAVI. Within the first step both time series were analysed over a period of 29 years to find best cross correlation values between TAMSAT rainfall and NDVI signal itself. The results indicate the strongest correlation for a weighted mean rainfall for a period of three months before the corresponding NDVI value. Based on these results different mathematical models (linear, logarithmic, square root, etc.) are tested to find a functional relation between the NDVI value and the 3-months rainfall period before (0.8). Finally, the resulting NDVI-Rain-Model can be used to determine a spatially individual correction factor to transform every NDVI value into an appropriate rain adjusted vegetation index (RAVI).
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Fernandes, Jeferson Lobato. "Monitoramento da cultura de cana-de-açucar no Estado de São Paulo por meio de imagens spot vegetation e dados meteorologicos". [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256961.
Abstract (sommario):
Orientadores: Jansle Vieira Rocha, Rubens Augusto Camargo LamparelliDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
Made available in DSpace on 2018-08-14T11:30:01Z (GMT). No. of bitstreams: 1 Fernandes_JefersonLobato_M.pdf: 2074887 bytes, checksum: af58e53746d7d186e6f1331527b3c3e8 (MD5) Previous issue date: 2009
Resumo: O atual sistema de previsão de safras para a cultura da cana-de-açúcar utilizado no Brasil depende, em boa parte, de informações subjetivas, baseadas no conhecimento de técnicos do setor e informações da cadeia produtiva. Apesar da experiência dos técnicos envolvidos, este sistema está sujeito a questionamentos sobre a qualidade dos números apresentados e abre margem a ações especulativas por parte de agentes externos. O monitoramento da cultura de cana-de-açúcar por meio de séries multitemporais de índices NDVI do sensor SPOT Vegetation, associado a dados meteorológicos provenientes do modelo do ECMWF, viabiliza o acompanhamento do desenvolvimento da cultura e sua correlação com a produtividade, diminuindo assim a subjetividade das estimativas. Este trabalho avaliou o potencial de uso de imagens decendiais do sensor SPOT Vegetation para a identificação de áreas canavieiras do estado de São Paulo e a capacidade de inferir sobre os dados de produtividade oficiais registrados em municípios e safras previamente selecionados, baseando-se em dados provenientes dos perfis temporais do NDVI - SPOT Vegetation e de variáveis meteorológicas do modelo do ECMWF. Foram selecionados 20 municípios do estado de São Paulo e sete safras compreendidas entre o período de 1999 e 2006. A identificação das áreas canavieiras foi realizada por meio do perfil temporal do NDVI de cada pixel, onde foram selecionados os pixels que ao longo da safra apresentaram comportamento característico da cultura. Para a determinação da produtividade média da safra por meio de dados espectrais e meteorológicos, foram extraídos valores dos perfis temporais do NDVI e das variáveis meteorológicas temperatura mínima, temperatura média, temperatura máxima, precipitação e radiação global, onde, utilizando-se técnicas de mineração de dados, separou-se a produtividade média da safra em 3 classes, baixo-média, média e média-alta. Os resultados de identificação de áreas canavieiras no estado de São Paulo foram avaliados em escala estadual e municipal. Para a escala estadual, o método proposto apresentou resultados satisfatórios. Os índices de determinação (R²), obtidos através da correlação entre a área colhida de cana-de-açúcar oficial e a estimada, por município e safra, considerando os 637 municípios do Estado, variaram entre 0,771 e 0,829. Para a escala municipal não foi possível determinar com exatidão a área de cana-de-açúcar colhida de cada município devido à baixa resolução espacial das imagens. Para o método de classificação da produtividade média municipal proposto, houve maior correlação com os dados os dados espectrais que com os dados meteorológicos. Valores extraídos do perfil temporal do NDVI entre os meses de dezembro e janeiro permitiram classificar a tendência do resultado de produtividade alcançado no final da safra. Os resultados foram mais efetivos para os casos onde a produtividade foi classificada como sendo média ou acima da média, com acertos de 86,5 e 66,7% respectivamente. Existe potencial no uso de imagens de NDVI do SPOT Vegetation para a identificação de áreas canavieiras em escala estadual e para a classificação da produtividade média municipal da safra.
Abstract: The current crop yield forecasting system for sugar cane used in Brazil is dependent on subjective information which are based on personal knowledge of technicians and information from the industry. Despite the experience of technicians, this system is vulnerable once it allows questioning about the quality of the figures presented, what could lead to speculation by market agents. Sugar cane monitoring through multitemporal series of the NDVI data from SPOT Vegetation, associated with meteorological data from the ECMWF model, provides information about the plant development and its correlation with yield, contributing to the decrease in the subjectivity of the forecasts. This study evaluated the potential use of decadal images of the SPOT Vegetation sensor to identify sugar cane areas in São Paulo state and the feasibility to estimate the official productivity registered in municipalities and crops previously selected by the use of NDVI - SPOT Vegetation and ECMWF meteorological data. For this study 20 municipalities of São Paulo state and seven cropping seasons were selected between 1999 and 2006. To identify sugar cane areas the temporal profile of each pixel was analysed during the cropping season, selecting pixels that presented a characteristic temporal NDVI profile of sugar cane. To determine the average yield using spectral and meteorological data, values of the temporal profiles of NDVI and minimum, mean and maximum temperature, precipitation and global radiation were extracted. Through data mining techniques, the average yield was classified in three classes: low-mean, mean and mean-high. Results for the identification of sugar cane areas in São Paulo state were evaluated at regional and local scale. For the regional scale the proposed method showed good results. The R² for the correlation between official and estimated sugar cane planted area, considering the 637 municipalities of the state, varied between 0,771 and 0,829. For the local scale, it was not possible to determine the sugar cane area due to the low spatial resolution of the images. For the classification of the average crop yield, by proposed method, spectral data was more relevant than meteorological data. Some values extracted from the temporal profile of NDVI between December and January permitted to classify the yield tendency. Best results were found when the yield was classified as mean or mean-high, with 86,5 and 66,7 percent correctively classified, respectively. The results showed that there is potential for the use of NDVI - SPOT Vegetation images to identify sugar cane areas at regional scale and to classify the average crop yield.
Mestrado
Planejamento e Desenvolvimento Rural Sustentável
Mestre em Engenharia Agrícola
11
Wessollek, Christine, e Pierre Karrasch. "Monitoring of vegetation dynamics on the former military training area Königsbrücker Heide using remote sensing time series". SPIE, 2016. https://tud.qucosa.de/id/qucosa%3A35117.
Abstract (sommario):
In 1989 about 1.5 million soldiers were stationed in Germany. With the political changes in the early 1990s a substantial decline of the staff occurred on currently 200,000 employees in the armed forces and less than 60,000 soldiers of foreign forces. These processes entailed conversions of large areas not longer used for military purposes, especially in the new federal states in the eastern part of Germany. One of these conversion areas is the former military training area Königsbrück in Saxony. For the analysis of vegetation and its development over time, the Normalized Difference Vegetation Index (NDVI) has established as one of the most important indicators. In this context, the questions arise whether MODIS NDVI products are suitable to determine conversion processes on former military territories like military training areas and what development processes occurred in the 'Königsbrücker Heide' in the past 15 years. First, a decomposition of each series in its trend component, seasonality and the remaining residuals is performed. For the trend component different regression models are tested. Statistical analysis of these trends can reveal different developments, for example in nature development zones (without human impact) and zones of controlled succession. The presented work ow is intended to show the opportunity to support a high temporal resolution monitoring of conversion areas such as former military training areas.
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Shen, Meicheng. "Statistical Estimation of Vegetation Production in the Northern High Latitude Region based on Satellite Image Time Series". The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1563552594966495.
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Adjei, Zola Yaa. "Using Remote Sensing to Explore the Time History of Emergent Vegetation at Malheur Lake, Oregon". BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5647.
Abstract (sommario):
The growth patterns of emergent vegetation can be a useful indicator for factors affecting lake health. However, field data to characterize emergent vegetation at many reservoirs may not be available or may be limited to small, isolated areas. We present a case study using remotely sensed data from the Landsat satellite to generate data to represent emergent vegetation in the near-shoreline and tributary delta areas of Malheur Lake, Oregon. We selected late June images for this study as vegetation is relatively mature in late June and visible, but has not completely grown-in providing a better indication of vegetation coverage in satellite images. We investigated the correlation of vegetation coverage (an indicator of emergent vegetation) with lake area on the day of the satellite collection, average daily maximum temperatures for April, May, June, and July, and average daily precipitation in June, all parameters that could affect vegetation. To estimate historic emergent vegetation extent, we computed the Normalized Difference Vegetation Index (NDVI) for 30 years of Landsat satellite images from 1984 to 2013. Around Malheur Lake we identified eight regions-of-interest (ROI): three inlet areas, three wet-shore areas (swampy areas), and two dry-shore areas (less swampy areas). For each ROI we generated time-series data to quantify the emergent vegetation as determined by the percent of area covered by pixels with NDVI values greater than 0.2. We measured lake area by computing the Modified Normalized Difference Water Index (MNDWI) and computing the area by summing the pixels that indicated water. We compared NDVI time-series values with the time series for lake area, June precipitation, and maximum daily temperatures for April, May, June, and July to determine if these parameters were correlated. Correlation would imply that emergent vegetation was influenced by the parameter. We found that correlations of vegetative extent in any of the eight ROIs with the selected parameters were minimal, indicating that there are other factors besides the ones chosen that drive emergent vegetation levels in Malheur Lake. This study demonstrates that Landsat data have sufficient spatial and temporal detail for quantification and description of ecosystem changes and thus offer a good source of information to understand historic trends in reservoir health. We expect that future work will explore other potential drivers for emergent vegetation extent, such as carp populations in Malheur Lake which are known to affect emergent vegetation. Carp were not considered in this study as we did not have access to data that reflect carp numbers over this 30 year period.
14
McMahon, William. "Pre-vegetation alluvium : geological evidence for river behaviour in the absence of land plants". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/276277.
Abstract (sommario):
Pre-vegetation alluvium is unique; at the present day, plants affect multiple aspects of river functioning and deposition and so those rivers that operated before the evolution of land plants largely lack modern sedimentological analogue. However, such rivers were the norm for the first 90% of Earth history and so a better understanding of their sedimentary product enables insight into both the fundamental underlying mechanisms of river behaviour and the ways in which fluvial processes operated on ancient Earth and other rocky planets. This study presents five original fieldwork based case studies and an analysis of a holistic database of all of Earth’s pre-vegetation alluvium. Together these research strands offer perspectives on the sedimentological characteristics and stratigraphic trends of pre-vegetation alluvium and the behaviour and functioning of pre-vegetation rivers. Results show that, in pre-vegetation alluvial settings: 1) a variety of fluvial styles are represented, but diminished in comparison with syn-vegetation alluvium; 2) ‘sheet-braided’ architectures are common but may record a variety of fluvial planforms; 3) meandering planforms were less frequent, particularly in small- to moderate-sized river systems; 4) mudrock is on average 1.4 orders of magnitude less common than it is in syn-vegetation alluvium; and 5) microbial matgrounds were present, but had negligible effect on preserved architecture and facies. This thesis demonstrates that whilst the physical laws governing fluvial fluid-sediment interaction have not changed, the theatre in which they operated irrevocably evolved with the greening of the continents.
15
Braget, Austin Ray. "Time series analysis of phenometrics and long-term vegetation trends for the Flint Hills ecoregion using moderate resolution satellite imagery". Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/35553.
Abstract (sommario):
Master of ArtsDepartment of Geography
J. M. Shawn Hutchinson
Grasslands of the Flint Hills are often burned as a land management practice. Remote sensing can be used to help better manage prairie landscapes by providing useful information about the long-term trends in grassland vegetation greenness and helping to quantify regional differences in vegetation development. Using MODIS 16-day NDVI composite imagery between the years 2001-10 for the entire Flint Hills ecoregion, BFAST was used to determine trend, seasonal, and noise components of the image time series. To explain the trend, 4 factors were considered including hydrologic soil group, burn frequency, and precipitation deviation from the 30 year normal. In addition, the time series data was processed using TIMESAT to extract eight different phenometrics: Growing season length, start of season, end of season, middle of season, maximum value, small integral, left derivative, and right derivative. Phenometrics were produced for each year of the study and an ANOVA was performed on the means of all eight phenometrics to assess if significant differences existed across the study area. A K-means cluster analysis was also performed by aggregating pixel-level phenometrics at the county level to identify administrative divisions exhibiting similar vegetation development. For the study period, the area of negatively and positively trending grassland were similar (41-43%). Logistic regression showed that the log odds of a pixel experiencing a negative trend were higher in sites with clay soils and higher burning frequencies and lower for pixels having higher than normal precipitation and loam soils. Significant differences existed for all phenometrics when considering the ecoregion as a whole. On a phenometric-by-phenometric basis, unexpected groupings of counties often showed statistically similar values. Similarly, when considering all phenometrics at the same time, counties clustered in surprising patterns. Results suggest that long-term trends in grassland conditions warrant further attention and may rival other sources of grassland change (e.g., conversion, transition to savannah) in importance. Analyses of phenometrics indicates that factors other than natural gradients in temperature and precipitation play a significant role in the annual cycle of grassland vegetation development. Unanticipated, and sometimes geographically disparate, groups of counties were shown to be similar in the context of specific phenology metrics and this may prove useful in future implementations of smoke management plans within the Flint Hills.
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Wessollek, Christine, e Pierre Karrasch. "Monitoring structural breaks in vegetation dynamics of the nature reserve Königsbrücker Heide". SPIE, 2017. https://tud.qucosa.de/id/qucosa%3A34984.
Abstract (sommario):
Nowadays remote sensing is a well-established method and technique of providing data. The current development shows the availability of systems with very high geometric resolution for the monitoring of vegetation. At the same time, however, the value of temporally high-resolution data is underestimated, particularly in applications focusing on the detection of short-term changes. These can be natural processes like natural disasters as well as changes caused by anthropogenic interventions. These include economic activities such as forestry, agriculture or mining but also processes which are intended to convert previously used areas into natural or near-natural surfaces. The Königsbrücker Heide is a former military training site located about 30 km north of the Saxon state capitol Dresden. After the withdrawal of the Soviet forces in 1992 and after nearly 100 years of military use this site was declared as nature reserve in 1996. The management of the whole protection area is implemented in three different management zone. Based on MODIS-NDVI time series between 2000 and 2016 different developments are apparent in the nature development zone and the zone of controlled succession. Nevertheless, the analyses also show that short-term changes, so called breaks in the vegetation development cannot be described using linear trend models. The complete understanding of vegetation trends is only given if discontinuities in vegetation development are considered. Structural breaks in the NDVI time series can be found simultaneously in the whole study area. Hence it can be assumed that these breaks have a more natural character, caused for example by climatic conditions like temperature or precipitation. Otherwise, especially in the zone of controlled succession structural breaks can be detected which cannot be traced back to natural conditions. Final analyses of the spatial distribution of breakpoints as well as their frequency depending on the respective protection zone allow a detailed view to vegetation development in the Köonigsbrüucker Heide.
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Osunmadewa, Babatunde Adeniyi, Worku Zewdie Gebrehiwot, Elmar Csaplovics e Olabinjo Clement Adeofun. "Spatio-temporal monitoring of vegetation phenology in the dry sub-humid region of Nigeria using time series of AVHRR NDVI and TAMSAT datasets". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-235570.
Abstract (sommario):
Time series data are of great importance for monitoring vegetation phenology in the dry sub-humid regions where change in land cover has influence on biomass productivity. However few studies have inquired into examining the impact of rainfall and land cover change on vegetation phenology. This study explores Seasonal Trend Analysis (STA) approach in order to investigate overall greenness, peak of annual greenness and timing of annual greenness in the seasonal NDVI cycle. Phenological pattern for the start of season (SOS) and end of season (EOS) was also examined across different land cover types in four selected locations. A significant increase in overall greenness (amplitude 0) and a significant decrease in other greenness trend maps (amplitude 1 and phase 1) was observed over the study period. Moreover significant positive trends in overall annual rainfall (amplitude 0) was found which follows similar pattern with vegetation trend. Variation in the timing of peak of greenness (phase 1) was seen in the four selected locations, this indicate a change in phenological trend. Additionally, strong relationship was revealed by the result of the pixel-wise regression between NDVI and rainfall. Change in vegetation phenology in the study area is attributed to climatic variability than anthropogenic activities.
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Osunmadewa, Babatunde A., Christine Wessollek e Pierre Karrasch. "Linear and segmented linear trend detection for vegetation cover using GIMMS normalized difference vegetation index data in semiarid regions of Nigeria". SPIE, 2015. https://tud.qucosa.de/id/qucosa%3A35266.
Abstract (sommario):
Quantitative analysis of trends in vegetation cover, especially in Kogi state, Nigeria, where agriculture plays a major role in the region’s economy, is very important for detecting long-term changes in the phenological behavior of vegetation over time. This study employs the use of normalized difference vegetation index (NDVI) [global inventory modeling and mapping studies 3g (GIMMS)] data from 1983 to 2011 with detailed methodological and statistical approach for analyzing trends within the NDVI time series for four selected locations in Kogi state. Based on the results of a comprehensive study of seasonalities in the time series, the original signals are decomposed. Different linear regression models are applied and compared. In order to detect structural changes over time a detailed breakpoint analysis is performed. The quality of linear modeling is evaluated by means of statistical analyses of the residuals. Standard deviations of the regressions are between 0.015 and 0.021 with R2 of 0.22–0.64. Segmented linear regression modeling is performed for improvement and a decreasing standard deviation of 33%–40% (0.01–0.013) and R2 up to 0.82 are obtained. The approach used in this study demonstrates the added value of long-term time series analyses of vegetation cover for the assessment of agricultural and rural development in the Guinea savannah region of Kogi state, Nigeria.
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Tsyganskaya, Viktoriya [Verfasser], e Ralf [Akademischer Betreuer] Ludwig. "Detection of temporarily flooded vegetation using time series of dual polarised C-band synthetic aperture radar data / Viktoriya Tsyganskaya ; Betreuer: Ralf Ludwig". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1212362969/34.
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Osunmadewa, Babatunde Adeniyi. "Spatio-Temporal Modeling of Vegetation Change Dynamics in the Guinea Savannah Region of Nigeria using Remote Sensing and GIS Techniques". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-229288.
Abstract (sommario):
The use of Normalized Difference Vegetation Index (NDVI) time series over the last decades has increased our understanding of vegetation change dynamics from global to regional scale through quantitative analysis of inter-annual trends in NDVI and climatological parameters (rainfall and temperature). Change in land cover induced by human activities such as livestock grazing and deforestation for large-scale farming (subsistence and mechanized) has influenced the ecological pattern of the Guinea savannah region (GSR) of Nigeria, thereby resulting in loss of biodiversity and changes in vegetation cover. In the context of the GSR of Nigeria where agriculture still plays a major role in people’s economy, it is important to identify the relationship between climatic variables, vegetation productivity and human activities which can be used to understand the on-going transition processes.
This study, therefore, examines the spatial and temporal relationship between NDVI and climate parameters, land use land cover change (LULCC) and the perspective of local people on vegetation change dynamics in the study region. In order to do this, bi-monthly NDVI3g time series datasets from Global Inventory Modeling and Mapping Studies (GIMMS), monthly rainfall datasets from Tropical Applications of Meteorology Satellite (TAMSAT), monthly temperature datasets from Climate Research Unit (CRU), national land use land cover (LULC) data of Nigeria from Forestry Management Evaluation & Coordination Unit (FORMECU), global land cover datasets from European Space Agency, Landsat imagery and socio-economic field data collection were used in order to understand vegetation change dynamics across the Guinea savannah regions of Nigeria.
Time series analysis (TSA) was applied to both NDVI and climate data used in order to examine the temporal dynamics of vegetation cover change and to detect NDVI-climate relationship during the period from 1983 through 2011. Both parametric and non-parametric statistical models were employed for the assessment of long-term inter-annual trend on the decomposed time series datasets for the whole region (Guinea savannah region) and selected locations. In addition to the TSA, harmonic regression analysis was performed on NDVI and rainfall datasets in order to examine change in seasonality and phyto-phenological characteristics of vegetation. Detection of change in land use and land cover was done by extracting information from existing land cover datasets (ancillary datasets). CLASlite was used for the assessment of the extent of deforestation, while linkage between remotely sensed data and social science was carried out via field surveys based on questionnaires in order to understand the drivers of vegetation change.
The study reveals that about 90 % of the Guinea savannah region show positive NDVI trends which indicate greening over time, while about 10 % of the region shows negative trends. This greening trends are closely related to regions where intensive agriculture is being practiced (also along inland valleys) while regions with negative trends show significant loss in woodlands (forest and shrublands) as well as herbaceous vegetation cover due to over-grazing by agro-pastoralism. The result confirms that there is a good relationship (statistically significant positive correlation) between rainfall and NDVI both on intra-annual and inter annual time scale for some selected locations in the study region (> 65 %), while negative statistical correlation exists between NDVI and temperature in the selected locations. This implies that vegetation growth (productivity) in the region is highly dependent on rainfall. The result of the harmonic regression analysis reveals a shift in the seasonal NDVI pattern, indicating an earlier start and a more prolonged growing season in 2011 than in 1983. This study proves significant change in LULC with evidence of an increase in the spatial extent of agricultural land (+ 30 %) and loss of woodlands (- 55 %) between 2000 and 2009 for Kogi State. The results of the socio-economic analysis (people’s perception) highlight that vegetation change dynamics in the study region are the resultant effects of increased anthropogenic activities rather than climatic variability. This study couples data from remote sensing and ground survey (socio-economics) for a better understanding of greening trend phenomena across the Guinea savannah region of Nigeria, thus filling the gap of inadequate information on environmental condition and human perturbation which is essential for proper land use management and vegetation monitoring.
21
Propastin, Pavel. "Remote sensing based study on vegetation dynamics in drylands of Kazakhstan". Doctoral thesis, Stuttgart Ibidem-Verl, 2007. http://hdl.handle.net/11858/00-1735-0000-0006-B26A-A.
22
Williams, Danielle M. "Time series analysis of vegetation dynamics and burn scar mapping at Smoky Hill Air National Guard Range, Kansas using moderate resolution satellite imagery". Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/34462.
Abstract (sommario):
Master of ArtsDepartment of Geography
J. M. Shawn Hutchinson
Military installations are important assets for the proper training of armed forces. To ensure the continued viability of training lands, management practices need to be implemented to sustain the necessary environmental conditions for safe and effective training. For this study two analyses were done, a contemporary burn history and a time series analysis. The study area is Smoky Hill Air National Guard Range (ANGR), an Impact Area (within the range) and a non-military Comparison Site. Landsat 5 TM / 7 ETM+ imagery was used to create an 11 year composite burn history image. NDVI values were derived from MODIS imagery for the time series analysis using the statistical package BFAST. Results from both studies were combined to make conclusions about training impacts at Smoky Hill ANGR and determine if BFAST is a viable environmental management tool. Based on this study the training within Smoky Hill ANGR does not seem to be having a negative effect on the overall vegetation condition. It was also discovered that BFAST was able to accurately detect known vegetation disturbances. BFAST is a viable environmental management tool if the limitations are understood.
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Romo, Leon Jose Raul. "Examining Trends in Post-Disturbance Ecosystem Dynamics in the Southwestern United States and Northwestern Mexico Using Remote Sensing Time-Series Data and Land Cover Change Detection". Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/205420.
Abstract (sommario):
New forms of disturbance, and alteration of current disturbance regimes in arid and semiarid ecosystems, have resulted in the modification and degradation of large regions. This research explores vegetation response as a consequence of two different disturbance events in the southwestern US and northwestern Mexico. This topic was explored in this dissertation utilizing remotely sensed geospatial information in three separate studies.The first study explores the development of methods to assess the effectiveness of pre-fire restoration efforts, by evaluating vegetation response as a function of local environmental variables. Here I evaluated three fire locations at Bandelier National Monument (New Mexico). My models explain post-fire vegetation response as a function of environmental inputs and pre-fire site conditions (restored, unrestored and control areas). However, further analysis will be needed to better understand the effect of pre-fire restoration techniques on post-fire vegetation response.My second study explores the development of monitoring practices using remotely sensed data to assess land cover dynamics through time. The study area was the arid agro-ecosystem of La Costa de Hermosillo (LCH) in northwestern Mexico. My results show a continuous tendency towards a decrease in agriculture from 1988 until 2009. Detailed change detection demonstrates high rates of change from agriculture to other land cover classes in areas with dense agricultural developments. Implementation of these monitoring protocols would help with the application of restoration practices.The third study we used remote sensing time series data to assess phenological trends and variability among land cover types in relation to climatic variability within communities present in a heavily impacted agro-ecosystem (LCH). My analysis comprised three different agricultural land cover types including abandoned agricultural fields, and four additional natural land cover classes. I found that productivity has not increased in abandoned fields (since abandonment). Furthermore, I found that the models developed in this study significantly explain phenological variability as a function of climatic variability.These studies suggest that the use of remote sensing tools could effectively contribute to our ability to monitor vegetation dynamics in arid ecosystems. The implementation of methodologies generated in this work would significantly inform managers in decision making processes.
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Minas, Michael Getachew. "Characterization of plant-water interaction in Kilombero River Catchment in Tanzania using Normalized Difference Vegetation Index (NDVI)". Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-110913.
Abstract (sommario):
Remote-sensing based indices such as Normalized Difference Vegetation Index have yielded valuable information about plant health. As the availability of water is one of the factors that controls plant's response to their environment, it is possible to indirectly studythe hydrology of an area via vegetation indices. Hence the thesis work used this tool to characterize the potential shifts in vegetation cover within and between years in Kilombero river catchment in Tanzania and make connection to the hydrology in the area. Separate time series analyses conducted on data pertaining to NDVI values and the areal coverage variability of arbitrarily defined NDVI-classes. The former data was extracted from a naturally vegetated wetland in the middle of the catchment while the latter from the topographically defined areas of the catchment. Results from the analyses showed that bothdatasets are sensitive to the seasonal rainfall while at inter-annual scale the areal coverage variability displayed significant correlations with past precipitation. Meanwhile the relatively higher sensitivity of the lowland area‟s NDVI to precipitation conforms to the initial assumption which emphasizes the importance of the wetland sub-catchment codenamed 1KB17 in describing Kilombero‟s hydrology. But the datasets show weak trends and it was not possible to make accurate future predictions on the hydrological conditions in the area. Meteorological distortions like clouds and environmental processes such as climate patterns or disturbances might have caused the problem in trend detection. Further studies needed to shed more light on the connection between land cover and hydrologic response in Kilombero.
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ANGELUCCI, GIOVANNA. "DINAMICA DI VEGETAZIONE IN AREE DI POST-ABBANDONO DELLA PIANURA PADANA". Doctoral thesis, Università degli Studi di Milano, 2011. http://hdl.handle.net/2434/154021.
Abstract (sommario):
VEGETATION DYNAMICS IN ABANDONED FIELDS IN THE PO PLAIN (ITALY)
Human impact and the mechanization of agricultural activitities have deeply modified the natural landscape in the Po plain (northern Italy), as well as in other countries. Forest vegetation in this area has strongly declined since the Neolithic (CASTELLETTI E ROTTOLI, 1998), with subsequent modifications of forest structure and floristic composition. Nonetheless, the recent decrease of agricultural pressure has enhanced the development of postcultural vegetation dynamics, allowing us to start an examination the vegetation dynamics in the Po plain.
In order to identify the dynamic series of the Po plain area, we have analyzed the secondary vegetation dynamics in sample abandoned fields of the upper plain of Milan and Lecco and woody communities of the Gera D’Adda neighbourhood (Bergamo) which, in dynamical terms, represents the final stage of the series.
The first case-study concerns the area of Rio Vallone Plis (Milan), which measures 1181 hectares and is located in the Pleistocene and Holocene alluvial sediments of the upper Po plain. The chronosequence or space-for-time substitution approach (PICKETT, 1989; FOSTER & TILMAN 2000) was applied to examine the temporal changes in vegetation. The method included the collocation of relevés in sites of different –preferably known– age at given time intervals, assuming that the samples would represent the distinct stages of a temporal series. The historical study was realized by comparing orthocorrected aerial photographs taken in different years (1954, 1980, 1998, 2003, and 2006). Fifty-six relevés were made by using the phytosociological approach (BRAUN – BLANQUET, 1932; WESTHOFF & VAN DER MAAREL, 1973). Two matrices (relevés/species, Landolt ecological index average values/cluster) were constructed from the resulting data set, in order to analyse the relationships between ecological variables and the different clusters of vegetation. Matrices were processed separately through a multivariate analysis approach (PCA) using the SYN-TAX 5.0 software (PODANI, 1995). The third matrice (relevés/life forms) was processed in order to analyse the relationships between life forms abundance and the age stage of the studied sites, through ANOVA analysis with the SPSS 10.0 software and later analysis by means of Pearson a 2-code correlation.
Nomenclature of taxa, corological elements and life forms follow PIGNATTI (1997) and AESCHIMANN & AL (2004).
Two main series of secondary succession were distinguished according to their environmental and soil conditions: (a) the acidophylous series of middle Pleistocene terrace (Mindel Auct.) develops from the first herbaceous nitrophylous stage, belonging either to Chenopodion glauci (igrophylous variant) or Dauco-Picridetum hieracioidis (mesoxerophylous variant), to a second herbaceous-shrubland stage, which can be referred to either to Convolvulo-Eupatorietum cannabini (igrophylous variant) or Convolvuletalia sepium (mesoxerophylous variant), to a third forest-edge stage that can be attributed to shrubland communities Prunetalia spinosae, and eventually to the last stage, which is represented by wood referable to Quercetalia robori petraeae. The regressive stage is identified by the communities of Prunus serotina; (b) the mesophylous series of Holocene terrace develops from the first nitrophylous herbaceous stage belonging to Arrhenatheretalia elatioris, to a second forest-edge stage referable to shrubland communities (Sambuco-robinieti) referable to Carpinion betuli, and to the final stage made up mesophylous oak-hornbeam wood attributed to Carpinion betuli. The regressive stage belongs to communities referred to Prunetalia spinosae
The second case study regards the phytosociological definition of the mesophylous and mesoigrophylous oak-hornbeam forests set on late Pleistocene and Holocene alluvial sediments of the upper Po plain, in the Gera d’Adda (Bergamo). Thirty-one relevés were performed by using the phytosociological approach (BRAUN – BLANQUET, 1932; WESTHOFF & VAN DER MAAREL, 1973). Two matrices were processed separately through a multivariate analysis approach (PCA) with the SYN-TAX 5.0 software (PODANI, 1994). The results indicate that clusters are distributed according to three main ecological gradients (defined by the LANDOLT index): soil moisture value (F); soil pH value (R); soil aeration value (D). The historical study, which was realized by comparing historical maps of different years (1833, 1889) with recent regional topographic maps (CTR, 1991), shows that Orfano Wood has relict characteristic. Orfano Wood is referred to two different associations: (a) Querco-Ulmetum Issler 1926 for the igrophylous communities on Holocene sediments; (b) Polygonato multiflori –Quercetum roboris subass. carpinetosum betuli Sartori 1980, which was included by ANDREIS e SARTORI (2002) in the Alnion incanae Pawlowski et Pawlowski et Wallisch 1928 (Alno-Ulmion minoris Br.-Bl. Et Tx.43), for the mesophylous communities developed on Holocene sediments.
Concerning the other wood located on the Pleistocene “main level of the Po plain”, the mesophylous woods belongs to Erythronio-Carpinion alliance (Hovart 1958) Marinček in Wallnöfer et al. 1993, with igrophylous variant referable to Alnion incanae Pawlowski et Pawlowski et Wallisch 1928 alliance (Alno-Ulmion minoris Br.-Bl. Et Tx.43).
26
Schwieder, Marcel. "Landsat derived land surface phenology metrics for the characterization of natural vegetation in the Brazilian savanna". Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19368.
Abstract (sommario):
Die Brasilianische Savanne, auch bekannt als der Cerrado, bedeckt ca. 24% der Landoberfläche Brasiliens. Der Cerrado ist von einer einzigartigen Biodiversität und einem starken Gradienten in der Vegetationsstruktur gekennzeichnet. Großflächige Landnutzungsveränderungen haben dazu geführt, dass annähernd die Hälfte der Cerrado in bewirtschaftetes Land umgewandelt wurde. Die Kartierung ökologischer Prozesse ist nützlich, um naturschutzpolitische Entscheidungen auf räumlich explizite Informationen zu stützen, sowie um das Verständnis der Ökosystemdynamik zu verbessern. Neue Erdbeobachtungssensoren, frei verfügbare Daten, sowie Fortschritte in der Datenverarbeitung ermöglichen erstmalig die großflächige Erfassung saisonaler Vegetationsdynamiken mit hohem räumlichen Detail. In dieser Arbeit wird der Mehrwert von Landsat-basierten Landoberflächenphänologischen (LSP) Metriken, für die Charakterisierung der Cerrado-Vegetation, hinsichtlich ihrer strukturellen und phänologischen Diversität, sowie zur Schätzung des oberirdischen Kohlenstoffgehaltes (AGC), analysiert. Die Ergebnisse zeigen, dass LSP-Metriken die saisonale Vegetatiosdynamik erfassen und für die Kartierung von Vegetationsphysiognomien nützlich sind, wobei hier die Grenzen der Einteilung von Vegetationsgradienten in diskrete Klassen erreicht wurden. Basierend auf Ähnlichkeiten in LSP wurden LSP Archetypen definiert, welche die Erfassung und Darstellung der phänologischen Diversität im gesamten Cerrado ermöglichten und somit zur Optimierung aktueller Kartierungskonzepte beitragen können. LSP-Metriken ermöglichten die räumlich explizite Quantifizierung von AGC in drei Untersuchungsgebieten und sollten bei zukünftigen Kohlenstoffschätzungen berücksichtigt werden. Die Erkenntnisse dieser Dissertation zeigen die Vorteile und Nutzungsmöglichkeiten von LSP Metriken im Bereich der Ökosystemüberwachung und haben demnach direkte Implikationen für die Entwicklung und Bewertung nachhaltiger Landnutzungsstrategien.The Brazilian savanna, known as the Cerrado, covers around 24% of Brazil. It is characterized by a unique biodiversity and a strong gradient in vegetation structure. Land-use changes have led to almost half of the Cerrado being converted into cultivated land. The mapping of ecological processes is, therefore, an important prerequisite for supporting nature conservation policies based on spatially explicit information and for deepening our understanding of ecosystem dynamics. New sensors, freely available data, and advances in data processing allow the analysis of large data sets and thus for the first time to capture seasonal vegetation dynamics over large extents with a high spatial detail. This thesis aimed to analyze the benefits of Landsat based land surface phenological (LSP) metrics, for the characterization of Cerrado vegetation, regarding its structural and phenological diversity, and to assess their relation to above ground carbon. The results revealed that LSP metrics enable to capture the seasonal dynamics of photosynthetically active vegetation and are beneficial for the mapping of vegetation physiognomies. However, the results also revealed limitations of hard classification approaches for mapping vegetation gradients in complex ecosystems. Based on similarities in LSP metrics, which were for the first time derived for the whole extent of the Cerrado, LSP archetypes were proposed, which revealed the spatial patterns of LSP diversity at a 30 m spatial resolution and offer potential to enhance current mapping concepts. Further, LSP metrics facilitated the spatially explicit quantification of AGC in three study areas in the central Cerrado and should thus be considered as a valuable variable for future carbon estimations. Overall, the insights highlight that Landsat based LSP metrics are beneficial for ecosystem monitoring approaches, which are crucial to design sustainable land management strategies that maintain key ecosystem functions and services.
27
Alhemiary, Abdulmaged [Verfasser], Gottfried [Gutachter] Jetschke, Sören Mathias [Gutachter] Hese e Sebastian [Gutachter] Schmidtlein. "Time series analysis of high resolution remote sensing data to assess degradation of vegetation cover of the island of Socotra (Yemen) / Abdualmaged Alhemiary ; Gutachter: Gottfried Jetschke, Sören Mathias Hese, Sebastian Schmidtlein". Jena : Friedrich-Schiller-Universität Jena, 2017. http://d-nb.info/1205682163/34.
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Jacquin, Anne. "Dynamique de la végétation des savanes en lien avec l’usage des feux à Madagascar : analyse par série temporelle d’images de télédétection". Phd thesis, Toulouse, INPT, 2010. http://oatao.univ-toulouse.fr/7223/1/jacquin.pdf.
Abstract (sommario):
Bien que le feu soit reconnu comme un facteur d’influence dans la dynamique de végétation des savanes, son rôle n’est pas clairement défini. Cette thèse aborde le problème de l’étude de la relation entre l’usage des feux et la dynamique de végétation. L’approche choisie repose sur l’analyse de séries temporelles d’images de télédétection à moyenne résolution spatiale. Les savanes étudiées sont situées sur le bassin versant de Marovoay au nord-ouest de Madagascar. Dans la mesure où il n’existe pas de consensus quant aux méthodes à utiliser, les savanes de Madagascar offrent un contexte particulier, en raison de la dégradation très prononcée du couvert végétal et des changements recherchés, pour tester les méthodes existantes et en proposer des nouvelles. Le premier objectif de ce travail est d’identifier le régime des feux à travers le suivi des variations spatio-temporelles des surfaces brûlées en milieu de savane. Pour cela, une méthode de cartographie des surfaces brûlées a été développée : elle est basée sur le calcul d’un indicateur annuel indiquant le passage d’un feu pendant la saison sèche et d’un indicateur saisonnier traduisant la période de passage du feu. Cette méthode, appliquée au site d’étude, a permis de produire une série temporelle de données utilisées pour caractériser le régime des feux à partir de deux paramètres, la période d’occurrence et la fréquence de passage du feu. En parallèle, le deuxième objectif consiste à caractériser la dynamique de végétation par l’analyse des variations spatio-temporelles de l’activité végétale. Deux approches de détection des changements, basées sur le traitement de série temporelle de NDVI, ont été testées. La première repose sur l’analyse des variations inter annuelles d’un indicateur phénologique traduisant l’activité végétale pendant la phase de croissance des savanes. La deuxième utilise une technique de décomposition temporelle pour extraire la tendance d’une série de NDVI. Dans les deux cas, les résultats ont permis de caractériser la dynamique de végétation à travers trois classes d’évolution de l’activité végétale (séries progressive, régressive ou stable). Ces résultats ont été évalués par comparaison avec ceux issus de techniques de détection des changements basées sur l’analyse diachronique d’images à haute résolution spatiale. Enfin, dans la dernière étape du travail, nous avons étudié les relations entre les informations relatives aux régimes des feux et à la dynamique de végétation en utilisant des modèles de régression multivariée. L’objectif est d’estimer l’importance et le rôle du feu dans la dynamique de végétation. Les résultats ont amené à trois conclusions : a) Le feu est un facteur de maintien des savanes ; b) Dans les situations où la pression liée aux activités anthropiques est faible, le feu, en particulier par la fréquence de son usage, est un facteur déterminant de la dynamique de végétation ; c) Dans les autres situations, l’interprétation des résultats est complexe et difficile, très certainement en raison de l’interaction de multiples facteurs anthropiques.
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Bouzahar, Chafika. "Phytosociologie paysagère et gestion conservatoire de la biodiversité dans le Dahra oriental". Electronic Thesis or Diss., Brest, 2022. http://www.theses.fr/2022BRES0049.
Abstract (sommario):
Le paysage végétal méditerranéen, dont la formation dépend principalement de l’action de l’homme, est actuellement menacé par l'augmentation des influences anthropiques qui provoquent une profonde modification des paysages. Les écosystèmes forestiers sont remplacés par des écosystèmes anthropisés, menaçant la biodiversité de cette région. Ce travail est mené dans le cadre de la gestion et la conservation de la biodiversité de la région méditerranéenne, en général, et celle de l’Algérie en particulier. Il consiste en la typologie et la cartographie de la végétation et des séries de végétation du Dahra oriental, dans le but de mieux comprendre l’importance des perturbations d’origine anthropique et de proposer la mise en place une gestion adaptée et raisonnée. La zone d’étude a été choisie comme région "pilote" pour son hétérogénéité géomorphologique et orographique, la pression anthropique qu’elle subit et les particularités de ses végétations caractérisées par des formations sensibles, instables et souvent dégradées. La phytosociologie paysagère permet d’une part l’étude et la description des trajectoires dynamiques des séries de végétation et d’autre part d’évaluer le poids de l’anthropisation dans le façonnement des paysages végétaux. La méthode phytosociologique paysagère, utilisée depuis plus de trois décennies en Europe, reste peu développée en Afrique du nord et plus précisément en Algérie. Ce travail constitue une première base qui pourra être poursuivie pour généraliser cette approche sur tout le pourtour nord-africain. Cette étude présente a permis d’identifier et de cartographier la végétation (actuelle et potentielle) et les séries de végétation, de comprendre leur trajectoire dynamique et d’identifier les zones à enjeux de conservation. Cela fournit aux acteurs de la gestion conservatoire de la biodiversité un outil permettant de déterminer le degré de conservation ou de dégradation de la végétation et d’identifier les secteurs impactés par les activités humaines en identifiant leur distance par rapport à la végétation potentielle naturelleThe Mediterranean vegetation landscape, whose formation depends mainly on human action, is currently threatened by the increase of anthropic influences that cause a profound modification of the landscape. Forest ecosystems are being replaced by anthropized ecosystems, threatening the biodiversity of this region.This work is conducted within the framework of the management and conservation of biodiversity in the Mediterranean region, in general, and that of Algeria in particular. It consists of the typology and mapping of vegetation and vegetation series of the eastern Dahra, in order to better understand the importance of disturbances of anthropogenic origin and to propose the establishment of an adapted and reasoned management.The study area was chosen as a "pilot" region because of its geomorphological and orographic heterogeneity, the anthropic pressure it is subject to and the particularities of its vegetation characterized by sensitive, unstable and often degraded formations.The landscape phytosociology allows on the one hand the study and the description of the dynamic trajectories of thevegetation series and on the other hand to evaluate the weight of the anthropization in the shaping of the vegetation landscapes.The landscape phytosociological method, used for more than three decades in Europe, remains little developed in North Africa and more specifically in Algeria. This work constitutes a first basis that could be pursued to generalize this approach on the whole North African perimeter.This study allows to identify and map vegetation (actual and potential) and vegetation series and to understand their dynamic trajectory and identifies areas of conservation concern. It provides a tool for biodiversity management and conservation stakeholders, that allows to determine the degree of conservation or degradation of vegetation, to identify areas impacted by human activities by identifying their distance from the natural potential vegetation
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Magidi, James Takawira. "Spatio-temporal dynamics in land use and habit fragmentation in Sandveld, South Africa". Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7886_1297841126.
Abstract (sommario):
This research assessed landuse changes and trends in vegetation cover in the Sandveld, using remote sensing images. Landsat TM satellite images of 1990, 2004 and 2007 were classified using the maximum likelihood classifier into seven landuse classes, namely water, agriculture, fire patches, natural vegetation, wetlands, disturbed veld, and open sands. Change detection using remote sensing algorithms and landscape metrics was performed on these multi-temporal landuse maps using the Land Change Modeller and Patch Analyst respectively. Markov stochastic modelling techniques were used to predict future scenarios in landuse change based on the classified images and their transitional probabilities. MODIS NDVI multi-temporal datasets with a 16day temporal resolution were used to assess seasonal and annual trends in vegetation cover using time series analysis (PCA and time profiling).Results indicated that natural vegetation decreased from 46% to 31% of the total landscape between 1990 and 2007 and these biodiversity losses were attributed to an increasing agriculture footprint. Predicted future scenario based on transitional probabilities revealed a continual loss in natural habitat and increase in the agricultural footprint. Time series analysis results (principal components and temporal profiles) suggested that the landscape has a high degree of overall dynamic change with pronounced inter and intra-annual changes and there was an overall increase in greenness associated with increase in agricultural activity. The study concluded that without future conservation interventions natural habitats would continue to disappear, a condition that will impact heavily on biodiversity and significant waterdependent ecosystems such as wetlands. This has significant implications for the long-term provision of water from ground water reserves and for the overall sustainability of current agricultural practices.
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Jimenez, Alberto Jr. "Restoration criteria on dolomite quarries on "Sierra de Mijas" mountain range". Thesis, Halmstad University, School of Business and Engineering (SET), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-958.
Abstract (sommario):
There are many dolomitic outcrops at Rondean sector (into the biogeographical Betic Province). Most of them, involve floral richness and vegetal endemic species due to its calcareous origin. These diverse organisms build peculiar plant communities. They can survive in extreme conditions as drought and high levels of Mg2+ cation. Many studies pronounce that these communities are unique, so they have to be conserved, and some of these plant communities are in the Habitats Directive 92/43 EC.
38% of the dolomitic outcrops can be affected by mining processes. Those particularly affected are dolomitic outcrops located in the mountains range of “Sierra Blanca” and “Sierra de Mijas”. Nowadays, there are 21 quarries in these mountains and they occupy more than 409 Ha. We have studied 11 dolomite quarries and surroundings on “Sierra de Mijas”. There is one vegetation serie on these areas (Rhamno oleoidis-Querco rotundifoliae sigmetum. Dolomitic section), knowing the plant communities we could draw with a Geographical Information System (GIS) the polygons where they are. And using the modified Botanic Value Index equation (Nieto et al., 1999) we could calculate the botanical value of these polygons. After that, we could establish a classification of the study area from the point of view of conservation interest, and we could set up new restoration criteria on these lands.
We have found that approximately the 53 % of the studied area has a high botanic value. There are many endemic taxa in the studied area and 4 species exclusive of the “Sierra de Mijas” mountain range. 90 % of the present communities are included in the Habitats Directive 92/43 CE, and three of the communities are exclusive of the studied area. This is the reason why these quarries have to be restored with a sustainable criteria.
Current restoration plans try to reforest with the climax vegetation (Quercus rotundifolia) or different species of pines (used in several previous reforestations). However, to restore a quarry these plans should include, in addition, other factors such as soil depth, structure of vegetal communities, botanic value, etc. And the Reforest Models of Valle (2004) propose sustainable restoration that could be usefull in the dolomite quarries of “Sierra de Mijas” mountain range.
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Cechim, Júnior Clóvis. "Mapeamento e estimativa de área de cana-de-açúcar no estado do Paraná". Universidade Estadual do Oeste do Parana, 2016. http://tede.unioeste.br:8080/tede/handle/tede/263.
Abstract (sommario):
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Previous issue date: 2016-02-04Sugarcane has been cropped and produced in Brazil for a long time, so, it deserves mention because it makes the country as the largest producer, with also representativeness in sugar and ethanol production. The knowledge of reliable estimates concerning their cropped areas is essential for Brazilian agribusiness, as they help in determining prices to producers by power plants as well as allow establishing logistics flow of production. The cropped areas estimates are made by official agencies. Therefore, in order to reduce this subjectivity, geotechnology use comes as an alternative since it has been widely used in mappings agricultural crops. Thus, this study aimed at developing a methodology for mapping sugarcane crop in Paraná State with satellite images as LANDSAT, IRS and spectrum-temporal series of vegetation indexes from MODIS sensor, for 2010/2011 to 2014/2015 harvesting season. The carried out mappings indicated a strong positive correlation concerning Canasat and official IBGE. The developed method was based on Fuzzy ARTMAP classification and was efficient to map and estimate the sugarcane cropped area using vegetation index in Paraná State.
A cana-de-açúcar como cultura cultivada e produzida no Brasil merece destaque, pois torna o País o maior produtor mundial, com representatividade também na produção de açúcar e etanol. O conhecimento de estimativas confiáveis de suas áreas cultivadas é imprescindível para o agronegócio brasileiro, por auxiliar na determinação dos preços aos produtores pelas usinas e permitir estabelecer a logística de escoamento da produção. As estimativas de área cultivada são realizadas de forma subjetiva pelos órgãos oficiais. Com a finalidade de diminuir tal subjetividade, surge como alternativa o uso de geotecnologias, as quais têm sido muito utilizadas em mapeamentos de culturas agrícolas. Diante disto, o objetivo deste trabalho foi o desenvolvimento de uma metodologia para o mapeamento da cultura de cana-de-açúcar para o Estado do Paraná usando imagens dos satélites LANDSAT, IRS e de séries espectro-temporais de índices de vegetação, provenientes do sensor MODIS, para as safras de 2010/2011 a 2014/2015. O mapeamento da cultura foi realizado a partir do modelo de classificação supervisionada Fuzzy ARTMAP, tendo como variáveis de entrada, termos harmônicos de amplitude e fase e as métricas fenológicas da cultura. Os mapeamentos realizados indicaram forte correlação positiva com relação aos dados do Canasat e oficiais IBGE. O método desenvolvido com base na classificação Fuzzy ARTMAP demonstrou ser eficiente para mapear e estimar a área cultivada da cultura de cana-de-açúcar utilizando índices de vegetação no Estado do Paraná.
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RAMMELOO, BENEDICTE. "Acupuncture et modifications du systeme nerveux autonome au cours d'une serie d'epreuves anxiogenes". Lyon 1, 1988. http://www.theses.fr/1988LYO1M241.
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Ribeiro, Eduardo Francisco. "Lineamento regional no norte do Pantanal separando áreas de vegetação fenológica e floristicamente distintas: evidências de diversidade ambiental originada por neotectônica". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/44/44137/tde-22082017-090048/.
Abstract (sommario):
O Pantanal é uma bacia sedimentar quaternária ativa de baixa declividade que vem sendo preenchida principalmente por megaleques fluviais. Apesar de possuir um relevo plano e uma geologia à primeira vista monótona, o Pantanal é um mosaico de ambientes distintos. A presença, intensidade e duração das inundações é considerada a mais importante causa da variabilidade ambiental, implicando que pequenas variações no relevo tenham drástica influência florística e fenológica. Estas variações espacialmente expressivas geram lineamentos de vegetação e captura de drenagens e estão associadas à neotectônica, também responsável pela sismicidade desta bacia. Para analisar este lineamento de vegetação, foram utilizadas diversas fontes de dados, incluindo imagens de sensoriamento remoto, dados de aeromagnetometria e dados florísticos obtidos em campo. A principal ferramenta foi uma série de 15 anos de imagens NDVI do sensor MODIS (345 imagens compostas de 16 dias). Com estas imagens foi abordada a fenologia da superfície terrestre (FSP) na área do lineamento, a qual apresenta uma notável variabilidade. Foram obtidos perfis temporais tanto contínuos como de um ano médio e uma série de métricas fenológicas, as quais foram analisadas com o auxílio de perfis de varredura e dados estatísticos. Os resultados da FSP demostraram a importante senescência associada ao período de seca ocorrendo apenas na porção a SE do lineamento, com a vegetação a NW permanecendo verde mesmo nos meses sem chuvas expressivas. Dados TRMM (2001-2015) mostram não haver grande diferença na pluviosidade da área do lineamento, e, quando comparados aos dados de NDVI, permitiram demonstrar maior relação entre verdor da vegetação e pluviosidade a SE do lineamento e independência do verdor às chuvas locais a NW. Apesar da indicação de que a área NW está mais baixa do que a área SE, isto não pode ser comprovado pelo modelo digital de elevação SRTM. Os dados florísticos obtidos em 17 parcelas de cobertura florestal em avançado estágio de reflorestação foram tratados em três abordagens: ordenação dos índices de similaridade de Jaccard (J), agrupamento hierárquico destes índices e obtenção do J considerando as parcelas feitas de cada lado do lineamento como amostras de uma mesma área (NW e SE). Os dados de geofísica sugerem que este lineamento seja a continuidade de uma zona de falhas a nordeste do Pantanal associada ao Lineamento Transbrasiliano. O conjunto dos dados caracteriza o lineamento estudado como um limite ambiental entre áreas que inundam com diferentes frequências e durações. Em função da extensão, linearidade e contexto tectônico, considera-se que o lineamento seja a expressão na vegetação de falha com componente vertical de rejeito, mostrando a importância da neotectônica na diversidade ambiental do Pantanal.The Pantanal is an active quaternary sedimentary basin of low slope that is being filled mainly by fluvial megafans. Despite having a flat relief and a geology at first glance monotonous, the Pantanal is a mosaic of different environments. The presence, intensity, and duration of floods are considered the most important cause of environmental variability, implying that small variations in the relief have a drastic floristic and phenological influence. These spatially expressive variations generate vegetation lineaments and stream captures and are associated to neotectonics, responsible for the seismicity of this basin. In order to analyze this vegetation lineament, several data sources were used, including remote sensing images, aeromagnetometry data and floristic data obtained in the field. The main tool was a series of 15 years of MODIS sensor NDVI images (345 composite images of 16 days). With these images, the land surface phenology (LSP) was approached in the region of the lineament, which presents a remarkable variability. Both continuous and one-year average temporal profiles and a series of phenological metrics were obtained, which were analyzed with the aid of swath profiles and statistical data. The LSP results demonstrated the important senescence associated with the drought period occurring only in the SE portion of the lineament, while the NW vegetation remaining green even in the months without expressive rains. TRMM data (2001-2015) showed that there is not a great difference in the rainfall of the region of the lineament, and when compared to the NDVI data, allowed to demonstrate a greater relation between greenness of the vegetation and rainfall to the SE of the lineament and independence of the greenness to the local rainfall to NW. Despite the indication that the NW region is lower than the SE region, this cannot prove by the SRTM digital elevation model. The floristic data obtained in 17 forest plots at an advanced regeneration stage were treated in three approaches: ordering the Jaccard (J) similarity indices, hierarchical clustering of these indices and obtaining the J considering the plots made on each side of the lineament as samples from the same region (NW and SE). The geophysical data suggest that this lineament is the continuity of a fault zone northeast of the Pantanal associated with the TransBrasilian Lineament. The data set characterizes the studied lineament as an environmental boundary between areas that flood with different frequencies and durations. Due to the extension, linearity and tectonic context, it is considered that the lineament is the expression in the vegetation of a fault with vertical displacement component, showing the importance of neotectonics in the environmental diversity of the Pantanal.
35
Delbosc, Pauline. "Phytosociologie dynamico-caténale des végétations de la Corse : méthodologies typologique et cartographique". Thesis, Brest, 2015. http://www.theses.fr/2015BRES0069/document.
Abstract (sommario):
À partir des années 1970 et notamment à travers les travaux de Tüxen (1978) puis de Géhu & Rivas-Martínez (1981), la phytosociologie dynamico-caténale a permis de mieux intégrer la dynamique des végétations en décrivant plus finement les trajectoires dynamiques des séries de végétation. Si les méthodologies d’étude des dynamiques des végétations se sont multipliées depuis les dernières décennies en Europe, de tels travaux restent peu nombreux en France. Un programme national de Cartographie des Habitats naturels et semi-naturels (CarHAB), lancé par le Ministère de l’Écologie, du Développement Durable et de l’Énergie, à partir de 2011, a pour objectif de cartographier les végétations et les séries de végétation de France métropolitaine à l’échelle du 1 : 25 000 d’ici 2025. Dans ce contexte, la Corse a été choisie comme région "pilote" pour les particularités de ses végétations méditerranéenne et alticole. Au-delà de cette singularité, l’évolution de la société agropastorale au cours du XXe siècle a profondément marqué le paysage végétal de Corse et constitue une des problématiques fondamentales permettant d’appréhender les changements des trajectoires dynamiques des végétations. La démarche méthodologique repose sur une méthode inductive et semi-déductive qui permet de décrire les systèmes de végétation de la Corse, à partir d’une approche phytosociologique. Notre étude, d’abord consacrée à l’approche bioclimatique, géomorphologique et phytogéographique, permet de typifier et de spatialiser les unités écologiques (géologie, géomorphologie, pédologie et bioclimatologie) afin de mieux appréhender les patrons écologiques qui régissent l’agencement et les zonations des végétations et plus largement les séries et les géoséries de végétation. Les fondements de la phytosociologie paysagère ont été révisés et adaptés aux objectifs de gestion conservatoire et d’aménagement du territoire, dans le cadre du programme CarHAB. 78 unités, soit 34 séries, 14 minoriséries et 30 géopermaséries sont décrites selon plusieurs critères : écologie, chorologie, structure et nomenclature de la tête de série, trajectoires dynamiques et conservation. Une méthode cartographique a été élaborée pour spatialiser les unités sigmétales et géosigmétales. L’ensemble des travaux cartographiques est présenté sous la forme d’un atlas cartographique concernant huit vallées et plateaux (Asco, Cap Corse, Niolu, Castagniccia, Haut-Vénacais, Plateau du Cuscione, Plateau calcaire de Bonifacio) et 31 sites littoraux.Quelques méthodes de bioévaluation sont testées et discutées, pour répondre aux enjeux de conservation des séries et des géoséries de végétation ainsi que de territoires protégés (étang de Biguglia, massif du Haut-Vénacais)Since the 1970’s and particularly through the works of Tüxen (1978) and Géhu & Rivas-Martínez (1981), the dynamico-catenal phytosociology allowed to better integrate vegetation dynamics, by describing more precisely the dynamic trajectories of vegetation series. If vegetations dynamic study methodologies have been developped over the recent decades in Europe, such works still remain scarce in France. A national program of habitat mapping (CarHAB), launched by the Ministry of Ecology, since 2011, aims to map the vegetation and vegetation series of metropolitan France at the scale of 1: 25 000 up to 2025. Within this context, Corsica has been chosen as a "pilot" region, due to its peculiarities regarding mediterranean and alticole vegetations. Beyond this singularity, the evolution of agropastoral society over the twentieth century caused main changes the landscape of Corsica and represents a major issue to understand the changes of dynamic trajectories of vegetation. Our methodology, based on an inductive and semi-deductive phytosociological approach, allows to describe vegetationsystems of Corsica.This study, firstly focused on bioclimatology, geomorphology and phytogeography, allows to typify and spatialize ecological units, in order to better understand ecological patterns that govern the layout and the zonation of vegetation and more widely vegetation series and geoseries. The principles of landscape phytosociology have been revised and adapted to the conservation management aims and spatial planning of the CarHAB program. 78 units, 34 series, 14 minoriseries and 30 geopermaseries are presented according to several descriptive criteria: ecology, chorology, serie head structure and nomenclature, dynamics trajectories and conservation.A mapping method was developed to spatialize sigmetal and geosigmetal units : the outcomes are presented in a mapping atlas concerning eight valleys and trays (Asco, Cap Corse, Niolu, Fium-Alto, Haut-Vénacais, Cuscione, Bonifacio) and 31 coastal sites.A few bioevaluation methods are tested and discussed to match the challenges of conservation series and vegetation géoséries, as well as evaluation protected sites (Biguglia, Haut-Vénacais)
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Rodrigues, Arlete da Silva. "Analysis of vegetation dynamics using time-series vegetation index data from Earth Observation Satellites". Doctoral thesis, 2014. https://repositorio-aberto.up.pt/handle/10216/77510.
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Rodrigues, Arlete da Silva. "Analysis of vegetation dynamics using time-series vegetation index data from Earth Observation Satellites". Tese, 2014. https://repositorio-aberto.up.pt/handle/10216/77510.
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Laštovička, Josef. "Hodnocení lesní vegetace pomocí časových řad družicových snímků". Doctoral thesis, 2020. http://www.nusl.cz/ntk/nusl-435801.
Abstract (sommario):
Příloha k disertační práci: Abstrakt v AJ (Mgr. Josef Laštovička) Abstract This dissertation thesis deals with the study of forest ecosystems in the central Europe with the time series of multispectral optical satellite data. These forest ecosystems have been influenced by biotic and abiotic disturbances for the last decade. The time series of the satellite data with high spatial resolution allow the detection and analysis of forest disturbances. This thesis is mainly focused primally on free available Landsat and Sentinel-2 data, these two data types were compared. From methods, the difference time series analyses / algorithms were used. The whole thesis can be divided into two main parts. The first one analyses usability of classifiers for detection of forest ecosystems with per-pixel and sub-pixel methods. Specifically, the Neural Network, the Support Vector Machine and the Maximum Likelihood per-pixel classifiers were used and compared for different types of data (for data with high spatial resolution - Landsat or Sentinel-2; very high spatial resolution - WorldView-2) and for classification of protected forest areas. The Support Vector Machine were selected as the most suitable method for forest classifications (with most accurate outputs) from the list of selected per-pixel classifiers. Also, Spectral...
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Cadman, Ann. "The relationship between pollen rain, vegetation, climate, meteorological factors and land-use in the PWV, Transvaal". Thesis, 1991. http://hdl.handle.net/10539/22026.
Abstract (sommario):
A two-year analysis of pollen rain was conducted in the Pretoria-Witwatersrand-Vereeniging district of the Transvaal, South Africa. Poaceae WaS the major component of the pollen assemblage, comprising 52% regionally. Of the total pollen count, 58.8% was non-seasonal and present throughout the year. During the analysis it became apparent that fungal spores dominated the atmospheric content, accounting for 94% of total airspora, considered here to incl ude pollen and fUngal spores.[Abbreviated Abstract. Open document to view full version].AC2017
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Laštovička, Josef. "Hodnocení časových řad družicových snímků k pozorování disturbancí v oblasti Nízkých Tater". Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-347029.
Abstract (sommario):
The work is aimed at finding appropriate methods for observing changes in the status of forest vegetation and its evaluation in the years 1992-2015. The satellite images of the Low Tatras are analyzed by using Time Series technology. Specifically, the images Landsat 4, 5, 7 and 8, for which it is necessary to perform a calibration and an adjustment of input data values to realize the individual vegetation indices, due to the fact that the images are captured by different sensors with different radiometric resolution. From this perspective, the work deals with the possibilities of normalized relative radiometric corrections and search for a particular type of appropriate compensation for Landsat CDR images. Calibrated data sets are evaluated by Time Series of different vegetation indices. The resulting values are evaluated in relation with the occurrence of forest disturbances, eg. wind storms, biological and other pests. The final part is discussion of the results, evaluating the test methods of calibration and suitability of vegetation indices for observing the state of calamity. The App is created for generating the Time Series of Landsat images CDR and for preparing RRN datasets. Key words: Time Series, radiometric correction, atmospheric correction, Landsat CDR, vegetation indices,...