To see the other types of publications on this topic, follow the link: Vegetation monitoring.
Dissertations / Theses on the topic 'Vegetation monitoring'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Vegetation monitoring.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Roderick, Michael L. "Satellite derived vegetation indices for monitoring seasonal vegetation conditions in Western Australia." Thesis, Curtin University, 1994. http://hdl.handle.net/20.500.11937/518.
Full textAbstract:
The monitoring of continental and global scale net primary production remains a major focus of satellite-based remote sensing. Potential benefits which follow are diverse and include contributions to, and improved scientific understanding of, ecological systems, rangeland management, famine warning, agricultural commodity trading, and the study of global climate change.A NOAA-AVHRR data set containing monthly observations of green vegetation cover over a ten year period was acquired and analysed, to extract information on seasonal conditions. The data were supplied as a vegetation index, commonly known as the Normalised Difference Vegetation Index (NDVI), with a spatial resolution of approximately five km. The data set was acquired from three different satellites, and calibration problems were known to exist. A new technique was developed to estimate, and subsequently remove, the calibration bias present in the data.Monthly rainfall measurements were used as surrogate ground truth to validate the NDVI data. For regions of native vegetation, linear models relating NDVI to previous rainfall were derived, using transfer function techniques in common use in systems engineering. The models demonstrate that, in mid-latitude regions, the NDVI is a linear function of rainfall recorded over the preceding seven or eight months.Annual summaries of the image data were developed to highlight the amount and timing of plant growth. Three fundamental questions were posed as an aid to the development of the summary technique: where, when and how much? These summaries highlight the extraordinary spatial and temporal variations in plant growth, and hence rainfall, over much of Western Australia each year.Standard analysis techniques used in time series analysis, such as classical decomposition, were successfully applied to the analysis of NDVI time series. These techniques highlighted structural differences in the image data, due to land use, climatic factors and vegetation type.Overall, the results of the research undertaken in this study, using NOAA-AVHRR data in Western Australia, demonstrate that vegetation indices acquired from satellite platforms can be used to monitor continental scale seasonal conditions in an effective manner. As a consequence of these results, further research using this type of data is proposed in rangeland management and climate change modelling.
2
Roderick, Michael L. "Satellite derived vegetation indices for monitoring seasonal vegetation conditions in Western Australia." Curtin University of Technology, School of Surveying and Land Information, 1994. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=14815.
Full textAbstract:
The monitoring of continental and global scale net primary production remains a major focus of satellite-based remote sensing. Potential benefits which follow are diverse and include contributions to, and improved scientific understanding of, ecological systems, rangeland management, famine warning, agricultural commodity trading, and the study of global climate change.A NOAA-AVHRR data set containing monthly observations of green vegetation cover over a ten year period was acquired and analysed, to extract information on seasonal conditions. The data were supplied as a vegetation index, commonly known as the Normalised Difference Vegetation Index (NDVI), with a spatial resolution of approximately five km. The data set was acquired from three different satellites, and calibration problems were known to exist. A new technique was developed to estimate, and subsequently remove, the calibration bias present in the data.Monthly rainfall measurements were used as surrogate ground truth to validate the NDVI data. For regions of native vegetation, linear models relating NDVI to previous rainfall were derived, using transfer function techniques in common use in systems engineering. The models demonstrate that, in mid-latitude regions, the NDVI is a linear function of rainfall recorded over the preceding seven or eight months.Annual summaries of the image data were developed to highlight the amount and timing of plant growth. Three fundamental questions were posed as an aid to the development of the summary technique: where, when and how much? These summaries highlight the extraordinary spatial and temporal variations in plant growth, and hence rainfall, over much of Western Australia each year.Standard analysis techniques used in time series analysis, such as classical decomposition, were successfully applied to the analysis of NDVI time series. These techniques highlighted ++structural differences in the image data, due to land use, climatic factors and vegetation type.Overall, the results of the research undertaken in this study, using NOAA-AVHRR data in Western Australia, demonstrate that vegetation indices acquired from satellite platforms can be used to monitor continental scale seasonal conditions in an effective manner. As a consequence of these results, further research using this type of data is proposed in rangeland management and climate change modelling.
3
JULITTA, TOMMASO. "Optical proximal sensing for vegetation monitoring." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2015. http://hdl.handle.net/10281/70505.
Full textAbstract:
Monitoring vegetation dynamics represents a fundamental practice to evaluate the response of the vegetation to environmental changes. Optical proximal sensed data allow the monitoring of the temporal and spatial variability of vegetation properties under natural conditions. Vegetation optical properties can be used to indirectly derive information about the phenological and/or physiological status of the plants. Optical sensors commonly used in the field can be divided into broadband sensors (usually multispectral, e.g. RGB cameras) and narrowband sensors (both multispectral and hyperspectral devices, e.g. spectroradiometers). The potential applications of these two categories of sensors differ. While broadband sensors have been applied in the last years to track the phenological development of the vegetation, spectroradiometers have been shown to be suitable also for the characterization of plant physiological status. In fact hyperspectral systems provide a more detailed optical characterization of the analysed targets, nevertheless the systems have to be accurately characterized in terms of spectral and radiometric performances in order to obtain repeatable and comparable.
The first part of the research has been addressed to the determination of the sources of uncertainty of the optical measurement systems. Several of the most common optical devices available on the market have been characterized and compared. A particular attention has been paid to instrumental differences in the optical components which could affect the radiance measurements. Moreover the performances of spectroradiometers have been evaluated both indoors and outdoors in order to evaluate the impact of sensor characteristics on the estimation of parameters commonly used in vegetation studies. The analysis has been initially focused on the effect of different cosine receptors on the estimation of biochemical and biophysical properties of the vegetation, such as leaf area index and chlorophyll content. In a second step the analysis referred to the impact of instrumental characteristics (mainly spectral resolution and signal to noise ratio) on the estimation of the absolute value of sun-induced chlorophyll fluorescence. The results obtained suggest that instrument components affect the measurements and according to the required parameter estimations accuracy some instruments are more suitable rather than others.
The second part of the study has been focused on the use of proximal sensors to monitor the dynamics of terrestrial vegetation. For this purpose both broadband and narrowband sensors have been separately considered. The first analysis referred to the possibility of using broadband imaging systems to investigate the temporal and spatial phenological dynamics of an alpine ecosystem. The phenological analysis has been conducted using a 3-year time series of digital RGB images collected in a grassland site. This spatiotemporal analysis provided interesting insights into the role of plant species composition on phenology in complex ecosystems, such as alpine grasslands. This study case indicates the potential of using RGB digital cameras as a tool for long term phenological monitoring, allowing the spatial characterization of the investigated ecosystem. The possibility of using hyperspectral narrowband sensors to detect vegetation physiological changes was also evaluated. In particular, this analysis focused on the use of sun-induced chlorophyll fluorescence for the early detection of vegetation stress. The study was conducted during a controlled experiment designed to modify the functional status of actual photosynthesis. The results indicate that fluorescence is immediately affected by physiological changes as a demonstration that such estimates can be used to track physiological traits better than traditional remote sensing techniques based on optical broadband vegetation indices.
4
Messeh, Maged Farouk Zaky Abdel. "Global vegetation monitoring using ERS-1 scatterometer data." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298978.
Full text
5
Despain, Del W., Phil R. Ogden, George B. Ruyle, and E. Lamar Smith. "Some Methods For Monitoring Rangelands and Other Natural Area Vegetation." College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/304566.
Full text
6
Despain, Del W., Phil R. Ogden, George B. Ruyle, and E. Lamar Smith. "Some Methods for Monitoring Rangelands and Other Natural Area Vegetation." College of Agriculture, University of Arizona (Tucson, AZ), 1995. http://hdl.handle.net/10150/311743.
Full text
7
Scherrer, Pascal, and n/a. "Monitoring Vegetation Change in the Kosciuszko Alpine Zone, Australia." Griffith University. Australian School of Environmental Studies, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040715.125310.
Full textAbstract:
This thesis examined vegetation change over the last 43 years in Australia's largest contiguous alpine area, the Kosciuszko alpine zone in south-eastern Australia. Using historical and current data about the state of the most common vegetation community, tall alpine herbfield, this thesis addressed the questions: (1) what were the patterns of change at the species/genera and life form levels during this time period; (2) what were the patterns of recovery, if recovery occurred, from anthropogenic disturbances such as livestock grazing or trampling by tourists; (3) what impacts did natural disturbances such as drought have on the vegetation and how does it compare to anthropogenic disturbances; and (4) What are the benefits, limitations and management considerations when using long-term data for assessing vegetation changes at the species/genera, life form and community levels? The Kosciuszko alpine zone has important economic, cultural and ecological values. It is of great scientific and biological importance, maintaining an assemblage of vegetation communities found nowhere else in the world. It is one of the few alpine regions in the world with deep loamy soils, and contains endemic flora and fauna and some of the few periglacial and glacial features in Australia. The area also forms the core of the Australian mainland's most important water catchment and is a popular tourist destination, offering a range of recreational opportunities. The vegetation of the Kosciuszko alpine zone is recovering from impacts of livestock grazing and is increasingly exposed to pressures from tourism and anthropogenic climate change. At the same time, natural disturbances such as drought and fire can influence the distribution, composition and diversity of plants. Thus, there is a need for detailed environmental data on this area in order to: (1) better understand ecological relationships; (2) understand existing and potential effects of recreational and management pressures on the region; (3) provide data against which future changes can be assessed; and (4) provide better information on many features of this area, including vegetation, for interpretation, education and management. The research in this thesis utilised three types of ecological information: (1) scientific long-term datasets; (2) photographic records; and (3) a comparison of disturbed and undisturbed vegetation. This research analysed data from one of the longest ongoing monitoring programs in the Australian Alps established by Alec Costin and Dane Wimbush in 1959. Permanent plots (6 transects and 30 photoquadrats) were established at two locations that differed in the time since grazing and have been repeatedly surveyed. Plots near Mt Kosciuszko had not been grazed for 15 years and had nearly complete vegetation cover in 1959, while plots near Mt Gungartan showed extensive impacts of grazing and associated activities which only ceased in 1958. Some transect data from 1959 to 1978 have been analysed by the original researchers. The research presented in this thesis extends this monitoring program with data from additional surveys in 1990, 1999 and 2002 and applies current methods of statistical evaluation, such as ordination techniques, to the whole data set for the first time. Results indicated that the recovery from livestock grazing and the effects of drought have been the main factors affecting vegetation. Recovery from livestock grazing at the three transects at Gungartan was slow and involved: (1) increasing genera diversity; (2) increasing vegetation cover; (3) decreasing amounts of bare ground; and (4) a directional change over time in species composition. Patterns of colonisation and species succession were also documented. In 2002, 44 years after the cessation of grazing, transects near Mt Gungartan had similar vegetation cover and genera diversity to the transects near Mt Kosciuszko, but cover by exposed rock remained higher. A drought in the 1960s resulted in a temporary increase of litter and a shift in the proportional cover of life forms, as grasses died and herb cover increased at both locations. Proportions of cover for life forms reverted to pre-drought levels within a few years. The results also highlighted the spatial variability of tall alpine herbfield. The photoquadrats were surveyed in the years 1959, 1964, 1968, 1978 and 2001 and are analysed for the first time in this thesis. After comparing a range of methods, visual assessment using a 130 point grid was found to be the most suitable technique to measure vegetation cover and genera diversity. At the 18 quadrats near Mt Gungartan, there was a pattern of increasing vegetation cover as bare areas were colonised by native cudweeds and the naturalized herb Acetosella vulgaris. Revegetation from within bare areas largely occurred by herb species, while graminoids and shrub species predominately colonised bare ground by lateral expansion from the edges, eventually replacing the colonising herbs. At the 12 quadrats near Mt Kosciuszko, vegetation cover was almost complete in all years surveyed except 1968, which was at the end of a six year drought. Similar to the results from the transect study, the drought caused an increase in litter at both locations as graminoid cover declined. Initially herb cover increased, potentially as a result of decreased competition from the graminoids and a nutrient spike from decaying litter, but as the drought became more severe, herb cover also declined. Graminoid cover rapidly recovered after the drought, reaching pre-drought levels by 1978, and was at similar levels in 2001. Herb cover continued to decline after peaking in 1964. The photoquadrat study also documented the longevity and growth rates of several species indicating that many taxa may persist for several decades. It further provided insights into replacement patterns amongst life forms. In addition to assessing vegetation change following livestock grazing and drought at the long-term plots, recovery from tourism impacts was examined by comparing vegetation and soils on a closed walking track, with that of adjacent undisturbed tall alpine herbfield at a series of 22 paired quadrats. Fifteen years after the track was closed there was limited success in restoration. Over a quarter of the closed track was still bare ground with non-native species the dominant vegetation. Plant species composition differed and vegetation height, soil nutrients and soil moisture were lower on the track which had a higher compaction level than adjacent natural vegetation. The results presented in this thesis highlight that tall alpine herbfield is characterised by nearly entire vegetation cover which is dominated by graminoids, followed by herbs and shrubs in the absence of disturbance by livestock grazing, trampling or drought. The studies also showed that under quot;average" conditions, the relative cover of herbs and graminoids remained fairly stable even though there can be considerable cycling between them. Spatial variability in terms of taxa composition was high. The only common introduced species in unrehabilitated sites was Acetosella vulgaris, which was effective at colonising bare ground but was eventually replaced by other native species. However, in areas actively rehabilitated, such as on the closed track, non-native species introduced during revegetation efforts still persist with high cover 15 years after their introduction. Monitoring of vegetation change is also important at the landscape scale. This thesis provides a review of the potential use, the limitations and the benefits of aerial photography to examine vegetation change in the Kosciuszko alpine zone. Numerous aerial photography runs have been flown over the area since the 1930s for government agencies, industry and the military. Some of these records have been used to map vegetation communities and eroding areas at a point in time. Other studies compared different types and scales of photographs, highlighting in particular the benefits and potential of large scale colour aerial photography to map alpine vegetation. However, despite their potential to assess vegetation change over time, a temporal comparison of vegetation in the Kosciuszko alpine zone from aerial photographs has not been completed to this date. Historical photographs may not be easy to locate or access and difficulties with vegetation classification may restrict the practicality of using historical aerial photographs to assess vegetation change. Despite these issues, aerial photography may provide a very useful and efficient tool to assess changes over time when applied appropriately, even in alpine environments. The development of digital classification techniques, the application of statistical measures of error to both methodology and data, and the application of geographic information systems are likely to further improve the practicality of historical aerial photographs for the detection of vegetation change and assist in overcoming some of the limitations. The results presented in this thesis highlight the need for limiting disturbance, for ongoing rehabilitation of disturbed areas and for long-term monitoring in the Kosciuszko alpine zone. The results contribute to our understanding of how vegetation may change in the future and may be affected by new land use activities and climate change. This type of information, which otherwise would require the establishment of long-term studies and years of monitoring, can assist land managers of this and other important protected areas. The study highlights how the use and expansion of already existing datasets to gather ecological information can save considerable money and time, providing valuable data for current and emerging issues.
8
Scherrer, Pascal. "Monitoring Vegetation Change in the Kosciuszko Alpine Zone, Australia." Thesis, Griffith University, 2004. http://hdl.handle.net/10072/366283.
Full textAbstract:
This thesis examined vegetation change over the last 43 years in Australia's largest contiguous alpine area, the Kosciuszko alpine zone in south-eastern Australia. Using historical and current data about the state of the most common vegetation community, tall alpine herbfield, this thesis addressed the questions: (1) what were the patterns of change at the species/genera and life form levels during this time period; (2) what were the patterns of recovery, if recovery occurred, from anthropogenic disturbances such as livestock grazing or trampling by tourists; (3) what impacts did natural disturbances such as drought have on the vegetation and how does it compare to anthropogenic disturbances; and (4) What are the benefits, limitations and management considerations when using long-term data for assessing vegetation changes at the species/genera, life form and community levels?
The Kosciuszko alpine zone has important economic, cultural and ecological values. It is of great scientific and biological importance, maintaining an assemblage of vegetation communities found nowhere else in the world. It is one of the few alpine regions in the world with deep loamy soils, and contains endemic flora and fauna and some of the few periglacial and glacial features in Australia. The area also forms the core of the Australian mainland's most important water catchment and is a popular tourist destination, offering a range of recreational opportunities. The vegetation of the Kosciuszko alpine zone is recovering from impacts of livestock grazing and is increasingly exposed to pressures from tourism and anthropogenic climate change. At the same time, natural disturbances such as drought and fire can influence the distribution, composition and diversity of plants. Thus, there is a need for detailed environmental data on this area in order to: (1) better understand ecological relationships; (2) understand existing and potential effects of recreational and management pressures on the region; (3) provide data against which future changes can be assessed; and (4) provide better information on many features of this area, including vegetation, for interpretation, education and management. The research in this thesis utilised three types of ecological information: (1) scientific long-term datasets; (2) photographic records; and (3) a comparison of disturbed and undisturbed vegetation. This research analysed data from one of the longest ongoing monitoring programs in the Australian Alps established by Alec Costin and Dane Wimbush in 1959. Permanent plots (6 transects and 30 photoquadrats) were established at two locations that differed in the time since grazing and have been repeatedly surveyed. Plots near Mt Kosciuszko had not been grazed for 15 years and had nearly complete vegetation cover in 1959, while plots near Mt Gungartan showed extensive impacts of grazing and associated activities which only ceased in 1958. Some transect data from 1959 to 1978 have been analysed by the original researchers. The research presented in this thesis extends this monitoring program with data from additional surveys in 1990, 1999 and 2002 and applies current methods of statistical evaluation, such as ordination techniques, to the whole data set for the first time. Results indicated that the recovery from livestock grazing and the effects of drought have been the main factors affecting vegetation. Recovery from livestock grazing at the three transects at Gungartan was slow and involved: (1) increasing genera diversity; (2) increasing vegetation cover; (3) decreasing amounts of bare ground; and (4) a directional change over time in species composition. Patterns of colonisation and species succession were also documented. In 2002, 44 years after the cessation of grazing, transects near Mt Gungartan had similar vegetation cover and genera diversity to the transects near Mt Kosciuszko, but cover by exposed rock remained higher. A drought in the 1960s resulted in a temporary increase of litter and a shift in the proportional cover of life forms, as grasses died and herb cover increased at both locations. Proportions of cover for life forms reverted to pre-drought levels within a few years. The results also highlighted the spatial variability of tall alpine herbfield. The photoquadrats were surveyed in the years 1959, 1964, 1968, 1978 and 2001 and are analysed for the first time in this thesis. After comparing a range of methods, visual assessment using a 130 point grid was found to be the most suitable technique to measure vegetation cover and genera diversity. At the 18 quadrats near Mt Gungartan, there was a pattern of increasing vegetation cover as bare areas were colonised by native cudweeds and the naturalized herb Acetosella vulgaris. Revegetation from within bare areas largely occurred by herb species, while graminoids and shrub species predominately colonised bare ground by lateral expansion from the edges, eventually replacing the colonising herbs. At the 12 quadrats near Mt Kosciuszko, vegetation cover was almost complete in all years surveyed except 1968, which was at the end of a six year drought. Similar to the results from the transect study, the drought caused an increase in litter at both locations as graminoid cover declined. Initially herb cover increased, potentially as a result of decreased competition from the graminoids and a nutrient spike from decaying litter, but as the drought became more severe, herb cover also declined. Graminoid cover rapidly recovered after the drought, reaching pre-drought levels by 1978, and was at similar levels in 2001. Herb cover continued to decline after peaking in 1964. The photoquadrat study also documented the longevity and growth rates of several species indicating that many taxa may persist for several decades. It further provided insights into replacement patterns amongst life forms. In addition to assessing vegetation change following livestock grazing and drought at the long-term plots, recovery from tourism impacts was examined by comparing vegetation and soils on a closed walking track, with that of adjacent undisturbed tall alpine herbfield at a series of 22 paired quadrats. Fifteen years after the track was closed there was limited success in restoration. Over a quarter of the closed track was still bare ground with non-native species the dominant vegetation. Plant species composition differed and vegetation height, soil nutrients and soil moisture were lower on the track which had a higher compaction level than adjacent natural vegetation. The results presented in this thesis highlight that tall alpine herbfield is characterised by nearly entire vegetation cover which is dominated by graminoids, followed by herbs and shrubs in the absence of disturbance by livestock grazing, trampling or drought. The studies also showed that under quot;average" conditions, the relative cover of herbs and graminoids remained fairly stable even though there can be considerable cycling between them. Spatial variability in terms of taxa composition was high. The only common introduced species in unrehabilitated sites was Acetosella vulgaris, which was effective at colonising bare ground but was eventually replaced by other native species. However, in areas actively rehabilitated, such as on the closed track, non-native species introduced during revegetation efforts still persist with high cover 15 years after their introduction. Monitoring of vegetation change is also important at the landscape scale. This thesis provides a review of the potential use, the limitations and the benefits of aerial photography to examine vegetation change in the Kosciuszko alpine zone. Numerous aerial photography runs have been flown over the area since the 1930s for government agencies, industry and the military. Some of these records have been used to map vegetation communities and eroding areas at a point in time. Other studies compared different types and scales of photographs, highlighting in particular the benefits and potential of large scale colour aerial photography to map alpine vegetation. However, despite their potential to assess vegetation change over time, a temporal comparison of vegetation in the Kosciuszko alpine zone from aerial photographs has not been completed to this date. Historical photographs may not be easy to locate or access and difficulties with vegetation classification may restrict the
practicality of using historical aerial photographs to assess vegetation change. Despite these issues, aerial photography may provide a very useful and efficient tool to assess changes over time when applied appropriately, even in alpine environments. The development of digital classification techniques, the application of statistical measures of error to both methodology and data, and the application of geographic information systems are likely to further improve the practicality of historical aerial photographs for the detection of vegetation change and assist in overcoming some of the limitations. The results presented in this thesis highlight the need for limiting disturbance, for ongoing rehabilitation of disturbed areas and for long-term monitoring in the Kosciuszko alpine zone. The results contribute to our understanding of how vegetation may change in the future and may be affected by new land use activities and climate change. This type of information, which otherwise would require the establishment of long-term studies and years of monitoring, can assist land managers of this and other important protected areas. The study highlights how the use and expansion of already existing datasets to gather ecological information can save considerable money and time, providing valuable data for current and emerging issues.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
Full Text
9
Tadkaew, Nichanan. "Monitoring of seagrasses in Lake Illawarra, NSW." Access electronically, 2007. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20070821.142240/index.html.
Full text
10
R, A. Majdaldin, B. A. Osunmadewa, E. Csaplovics, and D. Aralova. "Remote sensing-based vegetation indices for monitoring vegetation change in the semi-arid region of Sudan." SPIE, 2016. https://tud.qucosa.de/id/qucosa%3A35109.
Full textAbstract:
Land degradation, a phenomenon referring to (drought) in arid, semi-arid and dry sub-humid regions as a result of climatic variations and anthropogenic activities most especially in the semi-arid lands of Sudan, where vast majority of the rural population depend solely on agriculture and pasture for their daily livelihood, the ecological pattern had been greatly influenced thereby leading to loss of vegetation cover coupled with climatic variability and replacement of the natural tree composition with invasive mesquite species. The principal aim of this study is to quantitatively examine the vigour of vegetation in Sudan through different vegetation indices. The assessment was done based on indicators such as soil adjusted vegetation index (SAVI). Cloud free multi-spectral remotely sensed data from LANDSAT imagery for the dry season periods of 1984 and 2009 were used in this study. Results of this study shows conversion of vegetation to other land use type. In general, an increase in area covered by vegetation was observed from the NDVI results of 2009 which is a contrast of that of 1984. The results of the vegetation indices for NDVI in 1984 (vegetated area) showed that about 21% was covered by vegetation while 49% of the area were covered with vegetation in 2009. Similar increase in vegetated area were observed from the result of SAVI. The decrease in vegetation observed in 1984 is as a result of extensive drought period which affects vegetation productivity thereby accelerating expansion of bare surfaces and sand accumulation. Although, increase in vegetated area were observed from the result of this study, this increase has a negative impact as the natural vegetation are degraded due to human induced activities which gradually led to the replacement of the natural vegetation with invasive tree species. The results of the study shows that NDVI perform better than by SAVI.
11
Ogunbadewa, Ebenezer Yemi. "Evaluating medium resolution satellite data for monitoring seasonal vegetation dynamics." Thesis, University of Salford, 2009. http://usir.salford.ac.uk/26845/.
Full textAbstract:
Quantitative monitoring of vegetation change over time is essential in understanding the environmental processes of which are important in climate change and global warming models, because vegetation change is an indicator of environmental variability. However, obtaining such information has been a challenge especially for vegetation phenology due to the lack of appropriate methods for quantitative assessment. There is therefore a need to derive methods to quantitatively characterize vegetation dynamics in order to monitor the effect of climate change on the biosphere and as inputs to global change models. The aim of this research was to test the relationships between ground-based measurement of leaf area index (LAI) and vegetation indices (VI) derived from satellite remote sensing instruments to quantitatively monitor vegetation dynamics in a broadleaf and coniferous forest in the UK. This research has four key hypotheses. First, phenological changes (which is the timing of recurring biological events in plants) in broadleaf and coniferous forest canopies may be characterized using ground-based measurement of LAI, because LAI is good proxy for vegetation phenology. Second, cloud cover frequency in the UK leads to a requirement for higher temporal resolution remote sensing data to monitor changes in vegetation phenology. Third, data from the Disaster Monitoring Constellation (DMC) satellites provides a sufficiently high temporal resolution for monitoring vegetation phenology in the UK. Fourth, vegetation indices derived from atmospherically corrected DMC data may be used to monitor vegetation phenology in the UK. Analysis of Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) cloud mask showed that the average of number of cloud free days at the UK test sites in the year 2005 was five days per month with a minimum of one cloud free day per month implying that high temporal resolution satellites like the DMC will be appropriate for monitoring vegetation change. Nine DMC satellite images were acquired over 2005/2006 for the study sites plus one coincident Landsat ETM+ in 2005. Four vegetation indices (VI) were derived from the satellite data sets and were related to LAI/PAI. PAI is the plant area index defined as the total surface area of both photosynthetic and nonphotosynthetic part of plant per unit ground area. A regression model was used to predict LAI/PAI and the root mean square error (RMSE) was determined for both sites. The RMSE of the observed and predicted LAI values show that the levels of errors at Risley Moss were 0.51 for LAI, 0.52 for overstorey PAI and 0.8 for total canopy while PAI was 1.1 for Charter's Moss. Therefore, the DMC and one Landsat ETM+ data set related to LAI/PAI can adequately retrieve biophysical parameter in the deciduous woodland. However, in the coniferous canopy the numbers of observations was fewer and the measurement errors larger leading to a requirement for more data in order to establish statistically significant and ecologically useful relationships. Improvements in the accuracy of ground-based LAI/PAI measurements, radiometric and atmospheric correction of satellite data are expected to increase the accuracy of such LAI/PAI estimates in future.
12
Sani, Yahaya. "Determination and monitoring of vegetation stress using hyperspectral remote sensing." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13740/.
Full textAbstract:
Stress causes crops to grow below their potential and this affects the vitality and physiological functioning of the plants at all levels leading to reduction in yield. Remote sensing of vegetation is regarded as a valuable tool for the detection and discrimination of stress, especially over large or sensitive regions. The main aim of the research carried out is to assess the potential of remote sensing to detect CO2 leakage from CCS repositories. Further to this, the capability of remote sensing to discriminate between stresses with similar mode of action is explored. Two stress factors were selected for study: (1) elevated concentrations of soil CO2 in the plant root zone and; (2) herbicide, applied at sub-lethal levels. To understand the effects of soil CO2 and herbicide stress on vegetation reflectance, field experiments were carried out on maize (2009) and barley (2010) to investigate the effects of elevated soil CO2 concentrations and of different levels of herbicide treatments on vegetation growth and canopy reflectance using hyperspectral remote sensing techniques. The findings from this study shows that the average canopy reflectance response of maize and barley to CO2 and herbicide stress were increased reflectance in the visible and decrease in near infra-red region as well as changes in the position and shape of the red-edge. The red-edge first-derivative for barley treated with CO2 were composed of maximum peaks between 716 and 730nm and smaller peaks at 699 and 759nm, the control had peaks at 727 and 730 nm, with similar smaller peaks. Barley treated with herbicide had early peaks (a day after treatment) at 697, 715 and 717nm with a shoulder at 759nm, as the experiment progressed (16 days after treatment) the stress became apparent and the peak remained stationary at 730nm, the magnitude decreased to 712nm at late treatment period (35 days after treatment). The control had single peak at 726nm. CO2 treated maize had double peaks at 718 and 730nm, with secondary peaks at 707 and 794nm. Maize treated with herbicide had maximum peaks at 716 and 723nm, with the shoulder at 759 nm; the peaks were similar with the control plots but decreased in magnitude. The main differences between the treatments were in the shape and positions of the peaks that identify the red-edge. The canopy reflectances of the plants were further analysed using the blue (400-550nm) and red (550-750nm). In these regions the main feature of concern is chlorophyll content. The analysis showed that the band depths of controls plants were deeper compared to the stressed plants which is dependent on the stress and crop type. Other vegetation indices used in this study were the Chlorophyll Normalized Difference Index (Chl NDI), the Pigment Specific Simple Ratio for chlorophyll a and b (PSSRa and PSSRb) and the Physiological Reflectance Index (PRI). The results show that they were promising indicators of early stress detection, some indices performed better than others depending on the stress type, species and duration of stress. Chl NDI was sensitive to high soil CO2 concentration in maize and barley, sub-lethal herbicide treatment at 10% - 40% level in barley and was insensitive to both low CO2 in the barley and maize as well as 10% herbicide treatment in maize. PSSRa was a good indicator of early CO2 stress in maize and high CO2 in barley as well as 10- 40% herbicide treatments. PSSRb could detect high CO2 level in maize and barley and all levels (5-40%) of herbicide treatments. PRI was insensitive to 5% herbicide treatment in barley but sensitive to high CO2 in maize at early stage of the experiment. This study has demonstrated that remote sensing approach could be deployed for discriminating between different stressors using their red-edge first-derivative peaks, band depths and vegetation indices.
13
Nyberg, Roger G. "Automating condition monitoring of vegetation on railway trackbeds and embankments." Doctoral thesis, Högskolan Dalarna, Informatik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:du-21465.
Full textAbstract:
Vegetation growing on railway trackbeds and embankments present potential problems. The presence of vegetation threatens the safety of personnel inspecting the railway infrastructure. In addition vegetation growth clogs the ballast and results in inadequate track drainage which in turn could lead to the collapse of the railway embankment. Assessing vegetation within the realm of railway maintenance is mainly carried out manually by making visual inspections along the track. This is done either on-site or by watching videos recorded by maintenance vehicles mainly operated by the national railway administrative body. A need for the automated detection and characterisation of vegetation on railways (a subset of vegetation control/management) has been identified in collaboration with local railway maintenance subcontractors and Trafikverket, the Swedish Transport Administration (STA). The latter is responsible for long-term planning of the transport system for all types of traffic, as well as for the building, operation and maintenance of public roads and railways. The purpose of this research project was to investigate how vegetation can be measured and quantified by human raters and how machine vision can automate the same process. Data were acquired at railway trackbeds and embankments during field measurement experiments. All field data (such as images) in this thesis work was acquired on operational, lightly trafficked railway tracks, mostly trafficked by goods trains. Data were also generated by letting (human) raters conduct visual estimates of plant cover and/or count the number of plants, either on-site or in-house by making visual estimates of the images acquired from the field experiments. Later, the degree of reliability of(human) raters’ visual estimates were investigated and compared against machine vision algorithms. The overall results of the investigations involving human raters showed inconsistency in their estimates, and are therefore unreliable. As a result of the exploration of machine vision, computational methods and algorithms enabling automatic detection and characterisation of vegetation along railways were developed. The results achieved in the current work have shown that the use of image data for detecting vegetation is indeed possible and that such results could form the base for decisions regarding vegetation control. The performance of the machine vision algorithm which quantifies the vegetation cover was able to process 98% of the im-age data. Investigations of classifying plants from images were conducted in in order to recognise the specie. The classification rate accuracy was 95%.Objective measurements such as the ones proposed in thesis offers easy access to the measurements to all the involved parties and makes the subcontracting process easier i.e., both the subcontractors and the national railway administration are given the same reference framework concerning vegetation before signing a contract, which can then be crosschecked post maintenance.A very important issue which comes with an increasing ability to recognise species is the maintenance of biological diversity. Biological diversity along the trackbeds and embankments can be mapped, and maintained, through better and robust monitoring procedures. Continuously monitoring the state of vegetation along railways is highly recommended in order to identify a need for maintenance actions, and in addition to keep track of biodiversity. The computational methods or algorithms developed form the foundation of an automatic inspection system capable of objectively supporting manual inspections, or replacing manual inspections.
14
Nyberg, Roger Gote. "Automating condition monitoring of vegetation on railway trackbeds and embankments." Thesis, Edinburgh Napier University, 2015. http://researchrepository.napier.ac.uk/Output/462294.
Full textAbstract:
Vegetation growing on railway trackbeds and embankments present potential problems. The presence of vegetation threatens the safety of personnel inspecting the railway infrastructure. In addition vegetation growth clogs the ballast and results in inadequate track drainage which in turn could lead to the collapse of the railway embankment. Assessing vegetation within the realm of railway maintenance is mainly carried out manually by making visual inspections along the track. This is done either on-site or by watching videos recorded by maintenance vehicles mainly operated by the national railway administrative body. A need for the automated detection and characterisation of vegetation on railways (a subset of vegetation control/management) has been identified in collaboration with local railway maintenance subcontractors and Trafikverket, the Swedish Transport Administration (STA). The latter is responsible for long-term planning of the transport system for all types of traffic, aswell as for the building, operation and maintenance of public roads and railways. The purpose of this research project was to investigate how vegetation can be measured and quantified by human raters and how machine vision can automate the same process. Data were acquired at railway trackbeds and embankments during field measurement experiments. All field data (such as images) in this thesis work was acquired on operational, lightly trafficked railway tracks, mostly trafficked by goods trains. Data were also generated by letting (human) raters conduct visual estimates of plant cover and/or count the number of plants, either on-site or in-house by making visual estimates of the images acquired from the field experiments. Later, the degree of reliability of (human) raters' visual estimates were investigated and compared against machine vision algorithms. The overall results of the investigations involving human raters showed inconsistency in their estimates, and are therefore unreliable. As a result of the exploration of machine vision, computational methods and algorithms enabling automatic detection and characterisation of vegetation along railways were developed. The results achieved in the current work have shown that the use of image data for detecting vegetation is indeed possible and that such results could form the base for decisions regarding vegetation control. The performance of the machine vision algorithmwhich quantifies the vegetation cover was able to process 98% of the image data. Investigations of classifying plants from images were conducted in in order to recognise the specie. The classification rate accuracy was 95%. Objective measurements such as the ones proposed in thesis offers easy access to the measurements to all the involved parties and makes the subcontracting process easier i.e., both the subcontractors and the national railway administration are given the same reference framework concerning vegetation before signing a contract, which can then be crosschecked post maintenance. A very important issue which comes with an increasing ability to recognise species is the maintenance of biological diversity. Biological diversity along the trackbeds and embankments can be mapped, and maintained, through better and robust mo nitoring procedures. Continuously monitoring the state of vegetation along railways is highly recommended in order to identify a need for maintenance actions, and in addition to keep track of biodiversity. The computational methods or algorithms developed formthe foundation of an automatic inspection system capable of objectively supporting manual inspections, or replacing manual inspections.
15
Horton, Malcolm. "The environmental impacts of seismic exploration in the Cooper Basin, upon lignum, Muehlenbeckia florulenta and spinifex, Triodia basedowii : a pilot study /." Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09ENV/09envh823.pdf.
Full text
16
Roberts, Simon John. "Monitoring the semi-natural vegetation of Crete from space : relationships between landscape and the normalised difference vegetation index." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611704.
Full text
17
Wang, Haitao. "Monitoring vegetation dynamics in Zhongwei, an arid city of Northwest China." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/48893.
Full textAbstract:
This case study used Zhongwei City in northwest China to quantify the urbanization and revegetation processes (1990-2011) through a unified sub-pixel measure of vegetation cover. Research strategies included: (1) Conduct sub-pixel vegetation mapping (1990, 1996, 2004, and 2011) with Random Forest (RF) algorithm by integrating high (OrbView-3) and medium spatial resolution (Landsat TM) data; (2) Examine simple Dark Object Subtraction (DOS) atmospheric correction method to support temporal generalization of sub-pixel mapping algorithm; (3) And characterize patterns of vegetation cover dynamics based on change detection analysis.
We found the RF algorithm, combined with simple DOS, showed good generalization capability for sub-pixel vegetation mapping. Predicted sub-pixel vegetation proportions were consistent for "pseudo-invariant" pixels. Vegetation change analysis suggested persistent urban development within the city boundary, accompanied by a continuous expansion of revegetated area at the city fringe. Urban development occurred at both the suburban and urban core areas, and was mainly shaped by transportation networks. A transition in revegetation practices was documented: the large-scale governmental revegetation programs were replaced by the commercial afforestation conducted by industries. This study showed a slight increase in vegetation cover over the time period, balanced by losses to urban expansion, and a likely severe degradation of vegetation cover due to conversion of arable land to desert vegetation. The loss of arable land and the growth of artificial desert vegetation have yielded a dynamic equilibrium in terms of overall vegetation cover during 1990 to 2011, but in the long run vegetation quality is certainly reduced.Master of Science
18
Manore, Michael J. (Michael John) Carleton University Dissertation Geography. "Potential vegetation indices from landsat thematic mapper imagery for crop monitoring." Ottawa, 1991.
Find full text
19
Weiss, Jeremy, and Michael Crimmins. "DroughtView: Satellite-based Drought Monitoring and Assessment." College of Agriculture, University of Arizona (Tucson, AZ), 2017. http://hdl.handle.net/10150/625291.
Full textAbstract:
6 pp.Remotely sensed data are valuable for monitoring, assessing, and managing impacts to arid and semi-arid lands caused by drought or other changes in the natural environment. With this in mind, we collaborated with scientists and technologists to redevelop DroughtView, a web-based decision-support tool that combines satellite-derived measures of surface greenness with additional geospatial data so that users can visualize and evaluate vegetation dynamics across space and over time. To date, users of DroughtView have been local drought impact groups, ranchers, federal and state land management staff, environmental scientists, and plant geographers. Potential new applications may include helping to track wildland fire danger. Here, we present the functionality of DroughtView, including new capabilities to report drought impacts and share map information, as well as the data behind it.
20
Hiederer, Roland. "Monitoring rangeland vegetation in the Sahel by Landsat MSS and NOAA AVHRR." Thesis, Cranfield University, 1991. http://dspace.lib.cranfield.ac.uk/handle/1826/3538.
Full textAbstract:
Quantities of herbaceous vegetation of Sahelian rangelands in Niger and Mali were compared to vegetation indices (VI) derived from Landsat MSS and NOAA AVHRR LAC images. Field data was collected in 1985,1988 and 1989 in Niger and an appropriate sampling scheme for the study area was developed. Herbaceous vegetation could be estimated to within t 150 kgha 1 at an 80% confidence level up to 1300 kgha -1. Establishing site positions was found to be a primary obstacle when selecting suitable sampling areas. Suggested is the use of Landsat MSS image hard-copies in combination with a global positioning system. Landsat MSS and NOAA AVHRR LAC data were available for dates corresponding to field surveys of 1985 and 1988. While Landsat MSS scenes were geometrically corrected to maps, NOAA AVHRR images were registered to Landsat MSS with a simulated resolution of 1.1 km. Data from both satellites were radiometrically corrected and standardized to atmospheric conditions to the image with the highest relative scene contrast for each study area. These reference images were identified on the basis of bare soil spectral reflectance values and a binary decision tree. Five methods of resampling image data to represent field sites were applied. - The image data sampling methods were found to have a significant influence on spectral reflectance values attributed to a site and, consequently, on the relationship between ground and satellite VIs. Ratio, normalized difference and perpendicular VIs (RVI, NDVI and PVI) were computed for each step of pre-processing procedures. For Landsat MSS VIs were also derived from average spectral reflectance values of bands 3 and 4 to simulate NOAA AVHRR channel 2. VIs were compared for the same sensor, between sensors and related to field data by using linear and logarithmic regression analyses. RVIs and NDVIs achieved very similar results, while PVIs showed a more variable relationship to ground data. Overall, VIs from simulated NOAA AVHRR channel 2 values were found to be not superior to those derived from just band 4. NOAA AVHRR VIs could be related to Landsat MSS ratio VIs by a single regression line for 1985 and 1988 growing seasons for Niger and Mali survey sites. For the inter-calibration a simulation of the NOAA AVHRR pixel size was found to be better suited than the high resolution Landsat MSS data.
21
Wellens, Jane. "Monitoring and modelling rangeland vegetation in Tunisia using satellite and meteorological data." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359492.
Full text
22
Costa, Francisco Gessivaldo Regino. "Geotechnologies applied to the monitoring of vegetation of MaciÃo de Baturità - CE." Universidade Federal do CearÃ, 2008. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=5143.
Full textAbstract:
FundaÃÃo de Amparo a CiÃncia e TecnologiaDevido Ãs condiÃÃes edafoclimÃticas, as serras Ãmidas do Cearà sÃo propÃcias para a produÃÃo agrÃcola e para a concentraÃÃo demogrÃfica. O MaciÃo de Baturità constitui-se em um dos mais expressivos compartimentos de relevo com proximidade ao litoral, sendo que sua sub-regiÃo serrana tem sido alvo das aÃÃes humanas desde o inÃcio da ocupaÃÃo da regiÃo. Os problemas ambientais identificados nessa regiÃo sÃo causados pelos desmatamentos oriundos de prÃticas agrÃcolas com tÃcnicas rudimentares, construÃÃes particulares de casas de veraneio, cultivos em Ãreas de acentuadas declividades e remoÃÃo da vegetaÃÃo das nascentes dos rios. AlÃm disso, um forte aumento da especulaÃÃo imobiliÃria aliada aos diversos eventos culturais de abrangÃncia nacional, tambÃm impulsionam o interesse pela mesma. Nesse sentido, a presente pesquisa faz uso das geotecnologias para analisar a perda da cobertura vegetal da sub-regiÃo serrana do MaciÃo de Baturità nos Ãltimos 21 anos. Se a contÃnua remoÃÃo da cobertura vegetal do MaciÃo de Baturità nÃo for contida, diversos problemas de cunho socioambiental serÃo realidade para as populaÃÃes que o habitam. Portanto, a administraÃÃo pÃblica deve exercer papel fiscalizador, reduzindo a aÃÃo da especulaÃÃo imobiliÃria e criar polÃticas voltadas para a geraÃÃo de renda e inclusÃo social. A EducaÃÃo Ambiental deve ser focada nas escolas e treinamentos devem ser aplicados aos pequenos agricultores para que possam utilizar o solo de maneira apropriada. Desta forma a Ãnsia por um desenvolvimento sustentÃvel poderà tornar-se real e as geraÃÃes futuras tambÃm poderÃo usufruir das belezas naturais do MaciÃo de BaturitÃ.
Because soil and climatic conditions, the humid mountain ranges of Cearà are propitious for the agricultural production and demographic concentration. The MaciÃo de Baturità consists in one of the most expressive relief compartments with proximity to the coast, being that its sub-mountain region has been target of the actions of human beings since the beginning of the occupation of the region. Environmental problems identified in this region are caused by the deriving deforestations of practical agriculturists with rudimentary techniques, particular constructions of summering houses, culti vation in areas of accented declivities and removal of vegetation the sources of rivers. Moreover, a sharp increase in property speculation allied to the various cultural events of national scope, also driving the interest in it. In this direction, the present research makes use of the geotechnologies to analyze the loss of the vegetal covering of the sub-region's mountain of the MaciÃo de Baturità in last 21 years. If the continuous removal of the vegetation cover of the M aciÃo de Baturità will not be contained, several problems of reality imprint prom otions will be for the people that inhabit. Therefore, the public administration must exercise supervisory role, reducing the share of property speculation and to c reate politics directed toward the income generation and social inclusion. The Env ironmental Education should be aimedat schools and training should be applied the small agriculturists so that they can use the soil in an appropriate manner. Thus the yearning for sustainable development could become real and future generations can also enjoy the beauty of the MaciÃo de BaturitÃ.
23
Wessollek, Christine, and Pierre Karrasch. "Monitoring structural breaks in vegetation dynamics of the nature reserve Königsbrücker Heide." SPIE, 2017. https://tud.qucosa.de/id/qucosa%3A34984.
Full textAbstract:
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.
24
Schroeder, Wilfrid. "Towards an integrated system for vegetation fire monitoring in the Amazon basin." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8168.
Full textAbstract:
Thesis (Ph. D.) -- University of Maryland, College Park, 2008.Thesis research directed by: Dept. of Geography. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
25
LATELLA, MELISSA. "Integrated approaches for monitoring and modeling vegetation in riparian and coastal environments." Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2971989.
Full text
26
Gauthier, Vicki Lee Ann. "An evaluation of two data sources and their effectiveness for vegetation monitoring in developing countries using Normalized Difference Vegetation Indices (NDVI)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33378.pdf.
Full text
27
Ross, Louise C. "Fifty years of vegetation and environmental change in the Scottish Highlands." Thesis, University of Aberdeen, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542656.
Full textAbstract:
Long-term data are valuable for detecting changes in vegetation composition, and investigating how vegetation is responding to environmental change. We use a range of approaches to quantify, characterise and interpret vegetation change in upland plant communities of the Scottish Highlands by comparing two datasets, collected in 1956-58 and 2007-08, on the species composition of representative plots in major vegetation types in the North-West Highlands and the East Central Highlands. Firstly, we validate the methodology used for relocating plots that were not permanently marked, by showing that temporal change is greater than local spatial heterogeneity in the vegetation. The results show evidence of biotic homogenisation in the vegetation, manifested through declining plant diversity and an increase in generalist species, particularly graminoids, at the expense of specialists, particularly dwarf-shrubs, lichens and forbs. Climate change in the form of increased oceanicity, and grazing were found to have been important in driving these changes, whereas nitrogen deposition had a smaller effect. These data were also applied to two issues in nature conservation management, showing that protected area status had no effect on the magnitude of vegetation change, and that indicator species of the key drivers of change could be identified. Finally, we show how long-term vegetation change data can be used in hypothesis formulation for experimental work, by carrying out an ex-situ manipulative experiment on an important upland graminoid species, Trichophorum germanicum. This thesis incorporates examples of the wide range of ecological questions and analytical approaches that can be investigated through revisitation studies.
28
Hood, Malcolm. "Monitoring fire fuel loads in fragmented vegetation cover types with remotely sensed data /." Title page, contents and abstract only, 1987. http://web4.library.adelaide.edu.au/theses/09AR/09arh777.pdf.
Full text
29
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.
Full textAbstract:
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.
30
Hearn, Suzanne M. "Perspectives in vegetation monitoring : an evaluation of approaches currently used in the UK." Thesis, Bangor University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516127.
Full text
31
Bell, Maria Aletta. "Monitoring rehabilitation success using remotely sensed vegetation indices at Navachab Gold Mine, Namibia." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97888.
Full textAbstract:
Thesis (MA)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Remote sensing and vegetation indices were evaluated for its usefulness to monitor the success of the rehabilitation programme of the decommissioned tailings storage facility (TSF1) of the Navachab Gold Mine, Karibib, Namibia. The study aimed to objectively illustrate the rehabilitation progression from tailings (baseline) to soil (capping) and vegetation (planted as well as natural). Baseline data sets of 2004 and 2005 were compared with imagery of 2009, 2010 and 2011. All the images were subjected to panchromatic sharpening using the subtractive resolution merge (SRM) method before georegistration. As no recent accurate topographical maps were available of the study area, the May 2010 image was used as a reference image. All other images were georegistered to this image. A number of vegetation indices (VIs) were evaluated. The results showed that the normalised difference vegetation index (NDVI) and the transformed vegetation index (TVI) provided the most promising results. Although the difference vegetation index (DVI) and enhanced vegetation index (EVI) distinguished the vegetation, rock, and soil classes, it was not as successful as the other VIs in classifying the rain water pond. TVI and NDVI were further evaluated for their efficacy in detecting changes. This was done by generating a series of change images and by qualitatively comparing them to false colour images of the same period. Both the NDVI and TVI delivered good results, but it was found that the TVI is more successful when water is present in the images. The research concludes that change analyses based on the TVI is an effective method for monitoring mine rehabilitation programmes.
AFRIKAANSE OPSOMMING: Afstandswaarneming en plantegroei-indekse is ge-evalueer vir die gebruikswaarde daarvan om sukses van die rehabilitasieprogram vir die geslote slykdam of tailings storage facility (TSF1) van die Navachab Goudmyn, Karibib, Namibië vas te stel. Die studie se doelwit was om die progressie in die rehabilitasie van slyk (basislyn) na grond (dekmateriaal) en plantegroei (aangeplant en natuurlik) te illustreer. Basislyndatastelle 2004 en 2005 is vergelyk met 2009, 2010, en 2011 beelde. Al die beelde is panchromaties verskerp deur die subtractive resolution merge (RSM) metode voor georegistrasie uit te voer. Aangesien geen onlangse, akkurate topografiese kaarte van die studiegebied beskikbaar was nie, is die beeld vir Mei 2010 as ‘n verwysingsbeeld gebruik. Al die ander beelde is op die laasgenoemde beeld gegeoregistreer. Die resultate het gewys dat die normalised difference vegetation index (NDVI) en die transformed vegetation index (TVI) die mees belowende resultate lewer. Al het die difference vegetation index (DVI) en enhanced vegetation index (EVI) goed onderskei tussen plantegroeiklasse en grond- en gesteentesklasse was dit nie so suksesvol met die klassifikasie van die reënwaterpoel nie. TVI en NDVI is verder geëvalueer vir effektiwiteit om verandering waar te neem. Dit is gedoen deur ‘n reeks van veranderingsbeelde te skep en dit dan kwalitatief met die valskleur-beelde vir dieselfde tydperk te vergelyk. Beide die NDVI en TVI het goeie resultate gelewer, maar die TVI was meer suksesvol om beelde met water te klassifiseer. Die navorsing lei tot die gevolgtrekking dat veranderingsanalises met die TVI ‘n effektiewe metode vir die monitoring van rehabilitasie programme is.
32
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.
Full textAbstract:
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.
33
Verrall, Brodie. "Assessing alpine vegetation dynamics using long-term ecological monitoring amidst rapid climate change." Thesis, Griffith University, 2023. http://hdl.handle.net/10072/420962.
Full textAbstract:
Alpine ecosystems occur above the bioclimatic treeline and support cryophilic plant communities with high endemism, which are governed by low temperatures and short growing seasons. However, the climate of many alpine ecosystems is changing rapidly with warming temperatures, declining snow cover and lengthening growing seasons. Alpine vegetation dynamics in response to changes in climate over recent decades have been observed via long-term ecological monitoring techniques, but such studies are less common in the southern hemisphere including in the marginal alpine ecosystems of the Australian Alps. Therefore, the scale, ecological processes and implications of climate-induced dynamics are less clear for this important ecological, cultural and socioeconomic region. The central aim of this thesis is to understand the responses of vegetation in the largest contiguous alpine area in the Australian Alps, the Kosciuszko alpine area, to climate change over recent decades across varying spatial scales.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
Full Text
34
CAMARO, GARCIA WALTHER CAMILO ANDRES. "Vegetation dynamics and their relationships with precipitation in Africa for drought monitoring purposes." Doctoral thesis, Politecnico di Torino, 2015. http://hdl.handle.net/11583/2604355.
Full textAbstract:
Drought affects more people than any other natural disaster and results in serious economic, social and environmental costs. The development of effective drought monitoring and early warning has been a significant challenge because of the unique characteristics of drought. In fact, considering the multifaceted nature of drought phenomena (i.e. hydrological, meteorological, and agricultural), a comprehensive and integrated approach is required to define effective Early Warning Systems (EWS), which are thus based on the monitoring of different drought-related parameters and complex drought indicators. In such a context, several studies have shown how temporary changes of vegetation indices and their anomalies are strongly correlated with precipitations, especially in arid and semi-arid environments. Besides, satellite-derived vegetation indicators and climatic data have been widely used to study and monitoring droughts and included in the main existing EWS developed by the international community (e.g. global systems, such as US-AID FEWSNET, JRC MARS FOODSEC, FAO GIEWS, or designed for a specific area of interest, as in the case of MESA South Africa Drought Monitoring, the US Drought Monitor, and the JRC European Drought Observatory).
In this work, a study aimed at investigating spatial and temporal vegetation dynamics in the whole Africa and their relationships with climate factors, considering as a base data long-term time-series of vegetation-related phenological parameters is proposed. The outcomes of this study have been used in order to define proper drought monitoring procedures to be used by ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action) for early warning purposes. In fact, in recent years, through its partnership with the World Food Programme (WFP), ITHACA has focused its efforts to develop an automated drought EWS, based on the monitoring of relevant environmental variables that allow the early detection of vegetation stress patterns and agricultural drought phenomena on a global scale, finally providing near real-time alerts about vegetation conditions and productivity. In particular, the fortnightly monitoring of satellite-derived vegetation indexes during growing seasons allows the early detection of water stress conditions of vegetation, and the assessment of derived phenological parameters. These parameters, coupled with the evaluation of precipitation conditions, allow the near real-time assessment of the vegetation productivity which can be expected at the end of the considered growing season. The timely detection of critical conditions in vegetation health and productivity, during a vegetation growing season, leads to the identification of the agricultural areas where crop failures are likely to occur. Finally, the proposed system incorporates a simplified drought vulnerability model, able to show food security conditions starting from the hazard situation evaluated in near real-time. The system outputs and information related to identified alerted areas are updated fortnightly and disseminated using a proper web display application.
The described study has been conducted using time-series of vegetation phenological parameters extracted from satellite-derived NDVI datasets (global 15-day NDVI time-series, available from 2000 to present, at a 5.6 km spatial resolution, derived from the MODIS MOD13C1 Terra CMG dataset), and precipitation time-series obtained from the Tropical Rainfall Measuring Mission TRMM mission (0.25° x 0.25° spatial resolution) Multisatellite Precipitation Analysis estimation, computed at daily intervals (TRMM 3B-42 daily data), for period of 1998-present.
For the purpose of the proposed statistical analysis, ten phenological metrics (the time for the start and the end of the season, the length of the season, the season base level, the time for the mid of the season, the largest NDVI data value during the season, the seasonal amplitude, the rate of increase at the beginning of the season and the rate of decrease at the end of the season, and, finally, the seasonal integral) have been extracted from the yearly NDVI function that best fits the original yearly NDVI time-series and considered for each vegetation growing season in the examined time interval (2000-2014). These metrics are able to describe synthetically the trend of the season in both the time and the integrated NDVI/time domains and are related to the seasonal vegetation productivity.
Different precipitation fortnightly time-series have been used for the study, obtained taking into consideration different cumulating intervals (1-3-6-9-12 months values).
Specific routines have been implemented in order to investigate, on a pixel basis, and to explain the statistical relationship between the considered time-series of phenological parameters and precipitation data. Obtained results have been spatially analyzed and aggregated taking into consideration different vegetation types, and maps showing the areas where the observed vegetation phenological parameters are largely dependent on rainfall patterns have been produced. Moreover, the precipitation cumulative interval and the period, in the year, when precipitation influence on vegetation productivity has proved to be significant, have been identified and discussed, also in relation to the rainfall seasonality and crop calendar in the examined area.
The monitoring of vegetation conditions based on the analysis of phenological metrics, as originally provided in the ITHACA drought EWS, proved to effectively support WFP activities in several cases (i.e. Niger and Chad 2009, Sahel 2012, Horn of Africa crisis 2011).
The final aim of conducted statistical study, object of this thesis work, was to correctly define the operational use of precipitation data for drought detection, in support to the vegetation monitoring procedures. The outcomes of the carried out work supported the planning and definition of effective procedures for the integration, where it is meaningful, in the ITHACA vegetation conditions monitoring activities , based on the analysis of phenological parameters, with the near real-time evaluation of precipitation deficits explained, for multiple time scales, using the Standard Precipitation Index (SPI). Indeed, the studied relationships between rainfall and vegetation dynamics allowed to determine the areas where the spatial and the temporal variability in vegetation conditions are closely related to the climate, and the best rainfall cumulating interval to be used for SPI monitoring purposes as well. In these areas, the fortnightly near real-time monitoring of the precipitation permits to earlier identify drought warnings, by considering also climate conditions before the start of the vegetation growing season. Moreover, in the same areas, the near real-time SPI analysis during the vegetation growing season supports the monitoring of phenological parameters in a way to identify very critical events characterized by both vegetation productivity and rainfall anomalies.
35
Baird, Kathryn J., Michael J. Ronayne, and Thomas III Maddock. "PRELIMINARY VEGETATION AND HYDROLOGIC ANALYSES FOR BINGHAM CIENEGA." Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/615776.
Full textAbstract:
This report is in two parts. The first part covers the ecological processes pertinent
to the restoration of Bingham Cienega. The second part presents a subregional groundwater
flow model for analyzing the water budget, stream and spring behavior, and water
table configuration. Because of the sparsity of ecological and hydrologic data, both parts
must be considered as preliminary studies.
36
Bloor, Marcus. "Review of current vegetation monitoring on privately protected land under ongoing economic use (grazing)." Thesis, University of Canterbury. School of Forestry, 2009. http://hdl.handle.net/10092/3681.
Full textAbstract:
There has been a noticeable shift in focus in biodiversity research in New Zealand over recent decades. Research has traditionally focused on biodiversity protection on the public estate, which was comprised primarily of ecosystems with lower productive potential (generally over 500m asl). Private lands generally have higher production potential and are often used for intensive cultivation and agricultural practices. They still however have significant potential for protecting biodiversity values. One of the key tools for protecting biodiversity values on privately owned lands in the Canterbury region are through legally binding QEII open space covenants and there is significant potential through industry certifications. QEII covenants are placed on the land in perpetuity and provide legally binding protection for biodiversity or landscape values within the covenant. This protection is voluntary and allows the land owner to continue to use the land for economic benefit providing it does not prove detrimental to biodiversity through monitoring outcomes. Case studies of QEII covenants that contain grazing clauses in the Canterbury region were used to determine what values are present and what monitoring is occurring in the field within these ecosystems. Photopoints and informal visual monitoring were the primary methods used by the QEII representatives to monitor vegetation in all of the covenants. Monitoring forms a critical feedback for all biodiversity protection. It is especially important to have an accurate feedback on vegetation condition and change from monitoring on properties that are grazed. Monitoring needs to be capable of providing sufficient information on vegetation change on these sites so that the most suitable grazing levels can be obtained by land managers. This thesis focuses on monitoring methods to ensure that this feedback is suitable and that the methods are cost effective. Current vegetation monitoring techniques were reviewed to determine which methods would be most suited to monitoring in these ecosystems where resources are tightly restricted and observers may not have existing skills and experience in monitoring these ecosystems. Methods reviewed were quadrats, transects, height-frequencies, photopoints, needle point, biomass, tagged plants, visual rank and remote sensing. Each method is described and then assessed on its suitability for monitoring tussock shrublands, with cost effectiveness being an important criterion. Of these methods quadrats, transects and height-frequencies were the most robust but also the most intensive and least cost effective methods. Visual rank, needle point and photopoints were the most cost effective, but are generally suited to monitoring single objectives. In most cases a combination of methods would be ideal to suit the objectives of the monitoring. QEII photopoint monitoring should follow guidelines more closely and include more complimentary information with their photographs. Clear monitoring objectives should be developed for every covenant that is grazed and these need to be determined before it is possible to accurately select appropriate monitoring methods. These objectives will also provide the monitoring program with more structure and direction. If possible a detailed management plan for each grazed covenant would be beneficial for values present. QEII are in a unique position, where they have the potential to develop a data base of biodiversity information for private land and contribute to other projects like the National Vegetation Survey (NVS).
37
Sluiter, Raymond. "Mediterranean land cover change : modelling and monitoring natural vegetation using GIS and remote sensing /." Utrecht : Koninklijk Nederlands Aardrijkskundig Genootschap [u.a.], 2005. http://www.loc.gov/catdir/toc/fy0614/2006436726.html.
Full text
38
Dehm, Dustin. "A Small Unmanned Aerial System (sUAS) Based Method for Monitoring Wetland Inundation & Vegetation." University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1556713788128588.
Full text
39
Louderback, Lisbeth A. "Changes in vegetation and human adaptation from the latest Pleistocene to late Holocene in the eastern Great Basin : the Blue Lake pollen record /." abstract and full text PDF (UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1446788.
Full textAbstract:
Thesis (M.A.)--University of Nevada, Reno, 2007."May 2007" Includes bibliographical references (leaves 138-151). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2008]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.
40
Ruiters, Melissa. "Monitoring water quality with riparian trees along the Berg River, Western Cape." University of the Western Cape, 2012. http://hdl.handle.net/11394/4621.
Full textAbstract:
Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol)Heavy metals and nutrients have long been regarded as pollutants to freshwater ecosystems. These elements have a detrimental effect on plants, animals and the water quality of rivers in South Africa. The Berg River flows from the mountains of Franschhoek to the West Coast of the Western Cape. It is an important river in Cape Town, as it is essential for water distribution to town, for agriculture and industry and also supports a rich diversity of organisms in the ecosystem. Along the river, many farms and towns are situated and many tributaries enter the river. The Berg River dam provides for a water supply during the drier periods of the year. Therefore it is crucial to maintain a good water quality. The study was driven by the need to increase the knowledge of water quality in the upper Berg River after the construction of a new major Berg River dam, constructed in 2007. This study investigated oxygen, water temperature, electrical conductivity, pH, ammonium, nitrate, nitrite in the water and cadmium, copper, lead, iron, zinc, potassium, sodium, calcium, magnesium and phosphorus found in water, sediment and three plant species at ten sites along the upper Berg River, Western Cape. The results showed that the electrical conductivity, pH and the concentrations of nitrate, calcium and magnesium increased downstream, whereas the water temperature decreased downstream. Nitrate, cadmium, copper, potassium, sodium, calcium and magnesium displayed a general increase towards the colder period in the water. Seasonally, copper and magnesium showed significant winter increase within the sediment. Nitrogen, iron and calcium levels within Salix sp., Acacia mearnsii and Brabejum stellatifolium increased downstream. Nitrogen, cadmium, copper, potassium, calcium, magnesium and phosphorus in the three species were higher in the warmer seasons and decreased in the colder. Sources of pollution stem from the Franschhoek and Dwars tributaries, urban and farm runoff.
41
Edwards, Marianne Clare. "Detection and monitoring of arid grazing land vegetation using ATSR-2 and geometric optical modelling." Thesis, University of Leicester, 1999. http://hdl.handle.net/2381/10234.
Full textAbstract:
This study focused on the Badia region of Jordan and examined how low spatial resolution Along Track Scanning Radiometer (ATSR-2) and Advanced Very High Resolution Radiometer (AVHRR) data can be used to detect and monitor changes in grazing land vegetation in semi-arid environments. Comparisons were made between a wide range of different vegetation indices calculated using the red and near-infrared wavebands of both ATSR-2 and AVHRR imagery and field data collected at a series of sampling sites exhibiting a wide range of percentage vegetation covers. For the ATSR-2 data both the nadir and forward sensor view angles were considered. Poor correlations were found between the vegetation indices and field-measured vegetation cover for the Badia region. It was found that highly reflective soils, very sparse vegetation, and the xerophytic nature of vegetation in and regions limited the use of such indices. Furthermore, due to factors such as angle of view, spatial resolution and problems in geo-location, the forward view of ATSR-2 was not found to add any advantages in terms of the ability to detect and monitor the sparsely vegetated surfaces. As an alternative to vegetation indices, a hybrid geometric optical/empirically based model was developed for the area. Using the information given in the red/near-infrared scattergram of a satellite image, the model allowed percentage vegetation cover to be predicted from the remotely sensed data. Strong correlations (r² = 0.91) were found between the model-predicted percentage vegetation cover and that measured at the field sites. The estimates of percentage vegetation cover derived using the model were similar for both the ATSR-2 and the AVHRR imagery, suggesting that the model results are independent of sensor type. These results suggest that the geometric optical/ empirical model can improve the ability to map vegetation resources in and environments, and that the consistency of the results from the two different sensors should enable long term monitoring of the region.
42
Petrou, Zisis. "Remote sensing methods for biodiversity monitoring with emphasis on vegetation height estimation and habitat classification." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/26589.
Full textAbstract:
Biodiversity is a principal factor for ecosystem stability and functioning, and the need for its protection has been identified as imperative globally. Remote sensing can contribute to timely and accurate monitoring of various elements related to biodiversity, but knowledge gap with user communities hinders its widespread operational use. This study advances biodiversity monitoring through earth observation data by initially identifying, reviewing, and proposing state-of-the-art remote sensing methods which can be used for the extraction of a number of widely adopted indicators of global biodiversity assessment. Then, a cost and resource effective approach is proposed for vegetation height estimation, using satellite imagery from very high resolution passive sensors. A number of texture features are extracted, based on local variance, entropy, and local binary patterns, and processed through several data processing, dimensionality reduction, and classification techniques. The approach manages to discriminate six vegetation height categories, useful for ecological studies, with accuracies over 90%. Thus, it offers an effective approach for landscape analysis, and habitat and land use monitoring, extending previous approaches as far as the range of height and vegetation species, synergies of multi-date imagery, data processing, and resource economy are regarded. Finally, two approaches are introduced to advance the state of the art in habitat classification using remote sensing data and pre-existing land cover information. The first proposes a methodology to express land cover information as numerical features and a supervised classification framework, automating the previous labour- and time-consuming rule-based approach used as reference. The second advances the state of the art incorporating Dempster-Shafer evidential theory and fuzzy sets, and proves successful in handling uncertainties from missing data or vague rules and offering wide user defined parameterization potential. Both approaches outperform the reference study in classification accuracy, proving promising for biodiversity monitoring, ecosystem preservation, and sustainability management tasks.
43
Fatoki, Oluwakemi Busayo. "Monitoring the re-growth rate of alien vegetation after fire on Agulhas Plain, South Africa." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/1639.
Full text
44
Solans, Vila José Pablo. "Monitoring post-fire vegetation cover regeneration in the European Mediterranean Basin by means of remote sensing." Thesis, Cranfield University, 2007. http://dspace.lib.cranfield.ac.uk/handle/1826/3526.
Full textAbstract:
Obtaining quantitative information about the recovery of fire affected ecosystems is of utmost importance from the management and decision-making point of view. Nowadays the concern about natural environment protection and recovery is much greater than in the past. However, the resources and tools available for its management are still not sufficient. Thus, attention and precision are needed when decisions must be taken. Quantitative estimates on how the vegetation is recovering after a fire can be of help for evaluating the necessity of human intervention on the fire-affected ecosystem, and their importance will grow as the problem of forest fires, climate change and desertification increase. This thesis presents a comparison of methods to extract quantitative estimates of vegetation cover regrowth in burned areas with remote sensing data. In order to eliminate possible sources of error, a thorough pre-processing was carried out, including a careful geometric correction (reaching RMSE lower than 0.3 pixels), a topographic correction by means of a constrained Minneart model and a combination of absolute and relative atmospheric correction methods. Pseudo Invariant Features (PIF) were identified either by visual inspection methods or by a new automated selection method based in temporal Principal Component Analysis (PCA), which has been called multi-Temporal n-Dimensional Principal Component Analysis (mT-nD-PCA). This automated method demonstrated its capability in selecting accurate and objective PIFs within the satellite images. Spectral Mixture Analysis (SMA) was compared against quantitative vegetation indices which are based on well known traditional vegetation indices like Normalised Difference Vegetation Index (NDVI) and Modified Soil Adjusted Vegetation Index (MSAVI). Accuracy assessment was performed by regressing vegetation cover results obtained with each method, against field data gathered during the field work campaigns. Results obtained showed how vegetation cover fractions obtained with the NDVI based quantitative index were the most accurate, being superior to the rest of the techniques applied, including SMA.
45
Heumann, Benjamin W. "Mapping vegetation phenology in the Sahel and Soudan, Africa, 1982 to 2005." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101139.
Full textAbstract:
The Sahel and Soudan regions of Africa are hot-spots for vegetation change due to climatic and anthropogenic causes. Recent studies using remote sensing have demonstrated that vegetation recovery has occurred across the region questioning the occurrence of widespread land degradation in the region. These studies have focused on proxy measurements of net primary productivity, but have not addressed seasonal characteristics of vegetation such as phenology. This thesis examines how vegetation phenology has changed from 1982--2005 in the Sahel and Soudan regions and how phenology relates to observed bio-productivity and regional precipitation patterns. This is the first research to assess multi-decadal phenology change for a tropical ecosystem. Results show that while bio-productivity has significantly increased in the Sahel, significant phenology change has primarily been detected in the Soudan region. Furthermore, the relationship between phenology and bio-productivity and precipitation differs between the Sahel and Soudan. This research demonstrates the utility of measuring phenological change of a tropical ecosystem for vegetation monitoring applications.
46
Gonzalez, Shannon M. "Biological Indicators of Wetland Health: Comparing Qualitative and Quantitative Vegetation Measures with Anuran Measures." Scholar Commons, 2004. https://scholarcommons.usf.edu/etd/1049.
Full textAbstract:
Understanding wetland responses to human perturbations is essential to the effective management of Florida's surface and ground water resources. Southwest Florida Water Management District (SWFWMD) Rules (Chapter 40D-2.301(c) FAC) prohibit adverse environmental effects to wetlands, fish and wildlife caused by groundwater withdrawal. Numerous studies have documented the responses of biological attributes across taxa and regions to human disturbance. Biological assessment can provide information about ecological condition. Based on long-term monitoring conducted by the SWFWMD, the anthropogenic changes observed on the Starkey Wellfield are attributed to groundwater withdrawal.
Biological indicators are species, species assemblages, or communities whose presence, abundance, and condition are indicative of a particular set of environmental conditions. Monitoring early indicators of ecosystem stress may shorten response time by shifting attention to the relatively quick response of sensitive species. Species used to assess biological condition should be abundant and tractable elements of the system that provide an early, diagnosis.
Regulatory requirements within 40D-2 F.A.C. dictate an extensive analysis be conducted twice yearly on wetlands within all wellfields. This quantitative analysis provides information on the wetland plant community through the collection of eighteen categorized vegetative and physical variables. Because of the size of the area in which monitoring is required and the large number of wetlands, a rapid qualitative monitoring method was developed using vegetation and physical variables to classify wetlands into one of three categories based on their perceived health.
Wetland plants have many characteristics suited to assessments of biological condition including their diversity, taxonomy, distribution, relative immobility, well developed sampling protocols, and, for herbaceous species, their moderate sensitivity to disturbance (U.S. EPA 2002, Doherty et al. 2000). Because amphibians occupy both aquatic and terrestrial habitats in their life history, have physiological adaptations and specific microhabitat requirements, they are considered to be extremely sensitive to environmental perturbations and excellent barometers of the health of the aquatic and terrestrial habitats in which they reside (Vitt et al. 1990, Wake 1998, Blaustein 1994, Blaustein et al. 1994).
The purpose of my study was to 1) compare a qualitative method of wetland vegetation monitoring to a quantitative method, 2) document the reproductive success of anurans, and 3) compare anuran reproductive success to the vegetation monitoring results on the J. B. Starkey Wellfield (SWF). The results are published in chapters, with each chapter addressing one of the topics stated above.
The results show a rapid, qualitative measure of wetland health is useful for the determination of severely affected wetlands. The anuran reproductive success reflected similar results. The results show that wetlands can be categorized based solely on amphibian reproductive success variables. The anuran categorization, qualitative vegetative categorization, and quantitative vegetative categorization overlap on the high and low success wetlands. The low degree of overlap observed in the intermediate category could be attributed to fish predation in a wetland otherwise suited for amphibian reproduction, natural variability in the two years of anuran data collected or lag time inherent in vegetative monitoring. Strong correlative evidence suggests hydroperiod regulates anuran reproductive success on the J. B. Starkey Wellfield. The average length of inundation was correlated with the number of tadpoles captured per unit effort and the number of tadpole species captured per year (R=0.73, p<.01; R=0.70, p<.05). The average Julian date of inundation at which breeding attempts stopped and no tadpoles were observed was weeks within the published breeding season for many species. I detected a correlation between the number of species calling in each wetland and the number of tadpole species captured per year (R=0.87, p<.001) suggesting call censuses may be used at this site to estimate anuran reproductive success if enough well-timed observations are made. These findings will allow resource managers and regulators to evaluate and possibly refine land management practices, including existing monitoring methods, and water policy to meet the needs of resident amphibians at the J.B. Starkey Wellfield.
47
Wang, Wei J. "Monitoring the impact of surface coal mining on vegetation in southwestern Indiana using remote sensing and GIS." Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1399198.
Full textAbstract:
Surface coal mining leads to inevitable changes and notable impact on the physical environment of the earth and engenders immense damage to the landscape and the ecological environment. The dramatic high-speed rock digging and disturbance unavoidably causes ecosystem degradation and destruction. Detecting how surface coal mining affects the environment on the process of land use/cover change is one of the primary concerns to preserve nature and minimize the environmental impacts. Therefore, monitoring and understanding the environmental impact processes in mining areas is critical for sustainable management of the Earth's environment. In this thesis, remote sensing and Geographic Information System (GIS) are applied to assess the spatial environmental impact caused by surface coal mining in southwestern Indiana. The goal of this research is to develop a methodology to classify the coal mining field using satellite imagery and to quantify and assess land use /cover changes using remote sensing and GIS. The specific methods include classification of Landsat Thermal Mapper (TM) data and comparison of the spatial patterns of the classification results in the study region. The results are presented with a 3-D model to better understand and visualize the coal mining effects on the landscape. Results obtained in this study indicate the change area of land use/cover and the potential area for planting crops in southwestern Indiana. Based on the observation of the data results, vegetation in the study area was found to have changed significantly over the study period. In particular, the developed areas have been increasing quickly and the areas of agriculture and forests have been decreasing appreciably.Department of Geography
48
Wessollek, Christine, and 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.
Full textAbstract:
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.
49
Potgieter, Mary-Lee. "Long-term monitoring of elephant impact on the woody vegetation in the Tembe Elephant Park, South Africa." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/30940.
Full textAbstract:
The African Elephant is a key component of the savanna ecosystem. They contribute to the
generation of habitat for smaller vertebrates, as well as invertebrates, by the breaking of
branches or uprooting of trees. Elephants also play a role in seed dispersal, germination and
sapling recruitment. All these functions are advantageous to the ecosystem if the elephant
population size is acceptable for the size of the reserve and the amount of available forage.
The Tembe Elephant Park covers an area of 30 013 ha and is situated in northern KwaZulu
Natal. This reserve has a diversity of vegetation types and is part of the Maputaland Centre
of Plant Endemism and the Maputaland-Pondoland-Albany Hotspot of Biodiversity. Elephant
numbers in the park are currently high and the elephant population is still increasing. This is
threatening, especially to the endemic Sand Forest communities within the park.
The extent of elephant impact in Tembe Elephant Park, South Africa, was investigated and
compared to data collected six years prior to the current study. Elephant impact was
determined in 44 transects within nine communities across the park. Percentage canopy
removal was calculated for the woody individuals found in sites and with this data the
targeted size classes and species could be identified. The preferences of elephants for
specific woody species were determined by three electivity indices.
Elephant utilisation in Tembe Elephant Park, as reflected by percentage canopy removal,
increased since 2004 as the elephant population increased. Communities that experienced high values in 2010 of elephant utilisation were the Closed Woodland 1, Mature Sand
Forest, Open Woodland 1 and the Closed Woodland 3. Not only did the actual canopy
volume removed by elephant increase with approximately 57%, but the total canopy volume
available for browsing decreased extensively since 2004.
The size classes targeted by the elephants remained approximately the same from 2004 to
2010 although the 2010 results showed that elephant canopy removal percentage increased
in the large size classes. This was expected as elephants target individuals with large stem
diameters.
A change in the selection for woody species by elephants was clear, but the change in
species preference made future projections of canopy removal problematic. Elephants seem
to utilise a species at extreme levels until the species is almost extirpated, then they move
onto the next target species. This routine is evident in the results as highly preferred species
in 2004, with high canopy volumes available and removed, had low canopy availability and
electivity ratios in 2010, consequently the elephants moved on from these species as
individuals became scarce.
It was clear that the structure of individuals, populations and communities were being
altered, selected species were facing extirpation and composition of communities was
changed through the browsing manners of elephants. Management actions should be
implemented to prevent irreversible damage to the vegetation and to conserve the woody
species currently under threat.Dissertation (MSc)--University of Pretoria, 2012.
Plant Science
MSc
Unrestricted
50
Williams, Jeremy Hugh. "Monitoring the condition of semi-natural vegetation : the application of remote sensing and geographical information systems (GIS)." Thesis, Bangor University, 1992. https://research.bangor.ac.uk/portal/en/theses/monitoring-the-condition-of-seminatural-vegetation--the-application-of-remote-sensing-and-geographical-information-systems-gis(c90702cb-be4f-454f-aba1-1c74484c0093).html.
Full textAbstract:
The principal objective of this thesis was to investigate the use of remote sensing and Geographical Information System (GIS) technology in the survey and monitoring of semi-natural, vegetation. The effects of acidic deposition and airborne pollutants on vegetation were of particular interest during the 1980s and early 1990s. A first experiment studied the effect of simulated acid rain on the reflectance of birch seedlings. Plants exposed to acidic treatments lost the characteristic reflectance curve shape of healthy green vegetation. Spectroradiometer data were used to discriminate between plants in different rainfall treatments. A second experiment studied the effects of combinations of pollutant gases (03, S02+NO2, and 03+SO2+NO2) and acidic mists on the reflectance of white clover. Plants in the two treatments containing ozone showed marked changes in reflectance, and were statistically separable from the control. Simple and 4-waveband vegetation indices showed positive linear relationships with shoot dry weight. Plants in the treatments containing ozone showed marked decreases in shoot dry weight and vegetation index. Airborne Thematic Mapper (ATMý data were used to study the relationships between remotely-sensed radiance and water and soil chemistry on a large flood-plain mire in south Wales. Strong relationships between radiance and chemistry were found, suggesting associations between nutrient concentrations and the health and vigour of the mire vegetation. A study on the Glyderau mountains in Snowdonia investigated the potential for mapping upland vegetation using Landsat Thematic Mapper (TM) data. It addressed the problems involved in classifying highly variable ground cover on valley floors, steep slopes and high plateaux, and the problems involved in reconciling the need for a generalised vegetation map with the fine detail present on the ground and in TM data. Pre- and post-classification digital spatial filters were used to produce TM classmaps which agreed closely with the ground survey data. GIS was used to extract management information.