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1
Sheffield, Kathryn Jane, and kathryn sheffield@dpi vic gov au. "Multi-spectral remote sensing of native vegetation condition." RMIT University. Mathematical and Geospatial Sciences, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091110.112816.
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Native vegetation condition provides an indication of the state of vegetation health or function relative to a stated objective or benchmark. Measures of vegetation condition provide an indication of the vegetation's capacity to provide habitat for a range of species and ecosystem functions through the assessment of selected vegetation attributes. Subsets of vegetation attributes are often combined into vegetation condition indices or metrics, which are used to provide information for natural resource management. Despite their value as surrogates of biota and ecosystem function, measures of vegetation condition are rarely used to inform biodiversity assessments at scales beyond individual stands. The extension of vegetation condition information across landscapes, and approaches for achieving this, using remote sensing technologies, is a key focus of the work presented in this thesis. The aim of this research is to assess the utility of multi-spectral remotely sensed data for the recovery of stand-level attributes of native vegetation condition at landscape scales. The use of remotely sensed data for the assessment of vegetation condition attributes in fragmented landscapes is a focus of this study. The influence of a number of practical issues, such as spatial scale and ground data sampling methodology, are also explored. This study sets limitations on the use of this technology for vegetation condition assessment and also demonstrates the practical impact of data quality issues that are frequently encountered in these types of applied integrated approaches. The work presented in this thesis demonstrates that while some measures of vegetation condition, such as vegetation cover and stem density, are readily recoverable from multi-spectral remotely sensed data, others, such as hollow-bearing trees and log length, are not easily derived from this type of data. The types of information derived from remotely sensed data, such as texture measures and vegetation indices, that are useful for vegetation condition assessments of this nature are also highlighted. The utility of multi-spectral remotely sensed data for the assessment of stand-level vegetation condition attributes is highly dependent on a number of factors including the type of attribute being measured, the characteristics of the vegetation, the sensor characteristics (i.e. the spatial, spectral, temporal, and radiometric resolution), and other spatial data quality considerations, such as site homogeneity and spatial scale. A series of case studies are presented in this thesis that explores the effects of these factors. These case studies demonstrate the importance of different aspects of spatial data and how data manipulation can greatly affect the derived relationships between vegetation attributes and remotely sensed data. The work documented in this thesis provides an assessment of what can be achieved from two sources of multi-spectral imagery in terms of recovery of individual vegetation attributes from remotely sensed data. Potential surrogate measures of vegetation condition that can be derived across broad scales are identified. This information could provide a basis for the development of landscape scale multi-spectral remotely sensed based vegetation condition assessment approaches, supplementing information provided by established site-based vegetation condition assessment approaches.
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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.
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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.
3
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.
4
Zimmerli, Stephan. "Vegetation und Standort von Schwingrasen in der Schweiz = Vegetation and site condition of floating mats in Switzerland /." Zürich : Geobotanisches Institut der ETH, 1988. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=8701.
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McKune, Craig. "Rangeland condition in the Ceres Karoo: the importance of long-term studies." Bachelor's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/26017.
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The impact of the small stock industry on Succulent Karoo vegetation has long been acknowledged, and there is a need for researchers and managers to better understand the dynamics and processes leading to vegetation degradation and recovery. Despite the fact that these arid systems tend to hold high demographic inertia, as well as being prone to sudden and unpredictable events, there are few data-sets that are long enough (>50 yrs) to adequately distinguish 'noise' from true changes. This study examines an extensive data set of plant % cover, recorded using a rapid transect step-point technique, for the period between 1971 and 2002 throughout the Ceres Karoo. Correspondence analysis (CA) ordinations were used to show plant community changes from year to year at two sites: one that has been rested for many decades, and one that has used the Group Camp system since 1970. CA ordinations were also used to depict changes between 1992 and 2002 on three farms using different grazing systems. Results are discussed against the backdrop of the Stock Reduction Scheme initiated in the 1970's. Of the two farms examined from 1971 to 2002, the one using the group camp approach has shown an initial lag-period of about 10 years, and a subsequently steady and directional turnover of plant communities, increasing in cover of desirable species, until 2002. The rested farm showed no identifiable change. Of the farms studied between 1992 and 2002, a clear separation was found between the one using the Group Camp system and the others that are only grazed in winter. The former farm appeared to be showing the greatest amount of change. These results challenge the opinion that rested arid region veld is unlikely to recover. On the contrary, there has been a move toward more desirable veld since the 1970's in land that has not even been rested, but has had relatively reduced stock numbers. The more rested lands appear to be healthier than those that have been more frequently grazed, but they are not showing clear signs of change, supporting theories that arid region vegetation dynamics are characterised by a state and transition type of model. An important pattern to note is that changes from a degraded to a more desirable veld are characterised by a long lag period of more than 10 years, with subsequent changes occurring throughout a 20-year period. Thus the importance of allowing rangelands sufficient time to recover is highlighted, as is the importance of establishing, and continuing existing, long-term data sets.
6
Brown, Suzanne. "A statistical analysis of sequences of roadside vegetation condition ratings using Markov chains." Thesis, Brown, Suzanne (2000) A statistical analysis of sequences of roadside vegetation condition ratings using Markov chains. Honours thesis, Murdoch University, 2000. https://researchrepository.murdoch.edu.au/id/eprint/40846/.
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This thesis explores the modelling and analysis of sequences of ratings using Markov chains. The ratings, collected by Main roads WA, are the assessments of the roadside vegetation condition of consecutive road segments made by six different people. Our objective was to model the autodependence structure of the ratings. This enables standard errors of the proportions of the five possible ratings to be determined and provides insights useful for the collection of future ratings.
The autodependence of the observations in the sequences is captured using the matrix of transition probabilities for a Markov chain. These are the probabilities of the next segment of the road having a particular rating conditional on the rating of the current segment of road being known. The optimal parametrization for this matrix was then obtained using maximum likelihood estimation. We found that no simplifications to the matrix provided an adequate fit to the data.
The transition matrices revealed that raters stay with the same rating as for the previous road segment approximately sixty percent of the time.
The standard error and the sampling distribution of these proportions were estimated by simulation and the distributions were found to be approximately normal. The standard errors were also calculated using a mathematical approximation, but these only showed quasi agreement with the simulated values. The estimates were least satisfactory for ratings with small proportions in the Markov chain.
It was found that sequential sampling is about a quarter as efficient as random sampling when standard errors from each are compared.
Finally, statistical testing revealed significant differences between the transition probabilities for the urban and rural land use categories.
7
Ganesh, Srinivasan. "Investigation of the utility of the vegetation condition index (VCI) as an indicator of drought." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2517.
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Schwenke, Andrew C. "Riparian vegetation condition influences movement and microhabitat use by Mixophyes fasciolatus in South East Queensland." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/102339/4/Andrew_Schwenke_Thesis.pdf.
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Riparian vegetation has been impacted by urbanisation in many parts of Australia, resulting in population declines of numerous species of stream-associated frogs. This study was the first to investigate movement and microhabitat use of the stream-associated frog, Mixophyes fasciolatus, in sites that differed in the ecological condition of riparian vegetation in south-east Queensland. Twenty-nine frogs were tracked over a 48-hour period and their fine-scale movements and microhabitat use were examined and found to be related to riparian vegetation condition. These results have significant implications for the conservation management of this species.
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Ndou, Naledzani Nyahman. "Relating vegetation condition to grazing management systems in the central Keiskamma catchment, Eastern Cape Province, South Africa." Thesis, Nelson Mandela Metropolitan University, 2013. http://hdl.handle.net/10948/d1020645.
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Vegetation degradation in South Africa has been identified as a serious environmental problem, especially impacting communal areas. This study investigated the spatial distribution of vegetative condition, along with related changes, deterioration and trends, across the communal villages of the central Keiskamma catchment, Eastern Cape Province. The principal hypothesis of this study was that differences in grazing management strategies may explain the variations in vegetation condition within these communal areas. This investigation assessed the status and condition of vegetation in relation to local institutional grazing management systems, in association with factoring in relevant topographical and physical elements. Topographic homogeneity of the study area was tested by extracting topographic parameters from a DEM and performing a Chi squared test. Remote sensing techniques were used to analyse the spatial and temporal variations in vegetation condition between the villages. Landsat TM images, from 1984 and 1999, in conjunction with SPOT imagery of 2011, were used to assess the spatial trends in vegetation. Land use and cover maps were generated, comprising five categories of land cover, viz. intact vegetation; transformed vegetation; degraded vegetation; bare surfaces; and water. The classification of the images was achieved using the supervised object-oriented classification techniques, which aggregates pixels of each class into homogeneous objects. Information regarding existence and functionality of local institutional structures was obtained through structured interview method. Vegetation condition was correlated to grazing management systems, with the logistic regression confirming a significant relationship between vegetation condition and grazing management systems. Analysis of vegetation condition trends revealed a decline in pristine vegetation with an increase in degraded vegetation and exposed soil throughout the villages. However, it was observed that the decrease in pristine vegetation, with the associated increase in degraded vegetation and soil, do not occur evenly among the villages of the central Keiskamma catchment; the communal areas surrounding certain villages exhibited severe degradation of soil and vegetation, while other villages demonstrated less or minimal deterioration in their environs. The topographic homogeneity of the study locale lent credence to the theory that the uneven distribution of vegetation conditions between the villages is not controlled by topographic factors. Analysis of the data, collected through interviews, revealed differences in the functionality of institutional structures between villages. A statistically significant correlation between the vegetative condition and implementation of grazing management systems, supports the postulated concept that the variances in vegetation condition of the central Keiskamma catchment reflect the efficacy or inefficiency of the settlements‘ grazing management systems. Through gathering, analysing and assessing all the data, a conclusion was drawn, which advances that the primary requirement for remedial action in reversing the current decline in vegetation condition is strengthening the local institutional management regimes throughout all villages under study.
10
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.
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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.
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Aralova, Dildora, Kristina Toderich, Ben Jarihani, Dilshod Gafurov, and Liliya Gismatulina. "Monitoring of vegetation condition using the NDVI/ENSO anomalies in Central Asia and their relationships with ONI (very strong) phases." SPIE, 2016. https://tud.qucosa.de/id/qucosa%3A34865.
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An investigation of temporal dynamics of El Niño–Southern Oscillation (ENSO) and spatial patterns of dryness/wetness period over arid and semi-arid zones of Central Asia and their relationship with Normalized Difference Vegetation Index (NDVI) values (1982-2011) have explored in this article. For identifying periodical oscillations and their relationship with NDVI values have selected El Nino 3.4 index and thirty years of new generation bi-weekly NDVI 3g acquired by the Advanced Very High Resolution Radiometer (AVHRR) satellites time-series data. Based on identification ONI (Oceanic Nino Index) is a very strong El Nino (warm) anomalies observed during 1982-1983, 1997-1998 and very strong La Nino (cool) period events have observed 1988-1989 years. For correlation these two factors and seeking positive and negative trends it has extracted from NDVI time series data as “low productivity period” following years: 1982-1983, 1997 -1998; and as “high productivity period” following years: 1988 -1989. Linear regression observed warm events as moderate phase period selected between moderate El Nino (ME) and NDVI with following eriods:1986-1987; 1987-1988; 1991-1992; 2002-2003; 2009-2010; and moderate La Niña (ML) periods and NDVI (1998-1999; 1999-2000; 2007-2008) which has investigated a spatial patterns of wetness conditions. The results indicated that an inverse relationship between very strong El Nino and NDVI, decreased vegetation response with larger positive ONI value; and direct relationship between very strong La Niña and NDVI, increased vegetation response with smaller negative ONI value. Results assumed that significant impact of these anomalies influenced on vegetation productivity. These results will be a beneficial for efficient rangeland/grassland management and to propose drought periods for assessment and reducing quantity of flocks’ due to a lack of fodder biomass for surviving livestock flocks on upcoming years in rangelands. Also results demonstrate that a non-anthropogenic drivers of variability effected to land surface vegetation signals, nderstanding of which will be beneficial for efficient rangeland and agriculture management and establish ecosystem services in precipitation-driven drylands of Central Asia.
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Parkhurst, Tina. "Is tree planting enough? Investigation of soil condition and composition of vegetation and invertebrate assemblages after ecological restoration in agricultural landscapes." Thesis, Parkhurst, Tina (2021) Is tree planting enough? Investigation of soil condition and composition of vegetation and invertebrate assemblages after ecological restoration in agricultural landscapes. PhD thesis, Murdoch University, 2021. https://researchrepository.murdoch.edu.au/id/eprint/63209/.
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Globally, vegetation clearing for agriculture continues to cause biodiversity loss and land degradation. Restoration efforts to increase biodiversity and remediate land degradation are often constrained by legacies of agricultural land-use. Active restoration is often needed to overcome abiotic and biotic thresholds to assist re-assembly towards a reference ecosystem.
My thesis explores the effects of active restoration on soil condition and re-assembly of plant and invertebrate communities. I coupled a global meta-analysis with a field survey and experimentation in the Western Australian wheatbelt to examine effects of active woody plantings on various ecosystem components.
In a field survey of 30 plots, I characterised soil chemical properties, vegetation and ant assemblages in three vegetation states: fallow croplands, 10-year-old planted old fields and reference woodlands. In addition, I experimentally tested whether the addition of woody debris to planted old fields can accelerate restoration outcomes, using a multi-site Before-After Control-Impact design.
Results show that at a global scale, restoration has positive effects on soil condition, but inconsistent trends for invertebrate species. Overall, recovery remains incomplete. These results were mirrored at a local scale. Whilst concentrations of some soil nutrients in planted old fields were more similar to woodland reference system than fallow croplands, key abiotic thresholds, in particular elevated phosphorus concentrations, persisted. Woody species richness and cover on planted old fields were also similar to reference woodlands, but herbaceous species richness and cover, and large woody debris amounts, remained similar to the fallow cropland. Ant assemblages responded positively to changes in habitat, with increases of species richness and abundance of key functional groups, however full convergence to reference conditions was not observed. Addition of woody debris to planted old fields had few significant effects on soil chemical and biophysical properties and community re-assembly.
Overall, results show that soil condition, vegetation and invertebrate assemblages on planted old fields responded positively to restoration efforts, however, recovery remains incomplete. Future research should test the efficacy of additional restoration practices beyond tree planting and focus on identifying suitable functional groups of invertebrates to assess restoration outcomes.
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Tucker, David Ian. "The assessment of ecological condition in south-east Queensland, Australia: An evaluation of reliability across variable environments and surrogate efficacy for biodiversity values." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/94285/1/David_Tucker_Thesis.pdf.
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Multimetric ecological condition assessment has become an important biodiversity management tool. This study was the first to examine the reliability of these ecological surrogates across variable environments, and the implications for surrogate efficacy. It was demonstrated that through strategic application and design of the multimetric ecological condition index, the effects of environmental gradients and disturbance regimes can be mitigated, and that ecological condition assessment may serve as a scientifically rigorous approach for conservation planning.
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Bai, Yang. "Simulating Surface Flow and Sediment Transport in Vegetated Watershed for Current and Future Climate Condition." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/333038.
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The complex interaction between flow, vegetation and sediment drives the never settled changes of riverine system. Vegetation intercepts rainfall, adds resistance to surface flow, and facilitates infiltration. The magnitude and timing of flood flow are closely related to the watershed vegetation coverage. In the meantime, flood flow can transport a large amount of sediment resulting in bank erosion, channel degradation, and channel pattern change. As climate changes, future flood frequency will change with more intense rainfalls. However, the quantitative simulation of flood flow in vegetated channel and the influence of climate change on flood frequency, especially for the arid and semi-arid Southwest, remain challenges to engineers and scientists. Therefore, this research consists of two main parts: simulate unsteady flow and sediment transport in vegetated channel network, and quantify the impacts of climate change on flood frequency. A one-dimensional model for simulating flood routing and sediment transport over mobile alluvium in a vegetated channel network was developed. The modified St. Venant equations together with the governing equations for suspended sediment and bed load transport were solved simultaneously to obtain flow properties and sediment transport rate. The Godunov-type finite volume method is employed to discretize the governing equations. Then, the Exner equation was solved for bed elevation change. Since sediment transport is non-equilibrium when bed is degrading or aggrading, a recovery coefficient for suspended sediment and an adaptation length for bed load transport were used to quantify the differences between equilibrium and non-equilibrium sediment transport rate. The influence of vegetation on floodplain and main channel was accounted for by adjusting resistance terms in the momentum equations for flow field. A procedure to separate the grain resistance from the total resistance was proposed and implemented to calculate sediment transport rate. The model was tested by a flume experiment case and an unprecedented flood event occurred in the Santa Cruz River, Tucson, Arizona, in July 2006. Simulated results of flow discharge and bed elevation changes showed satisfactory agreements with the measurements. The impacts of vegetation density on sediment transport and significance of non-equilibrium sediment transport model were accounted for by the model. The two-dimensional surface flow model, called CHRE2D, was improved by considering the vegetation influence and then applied to Santa Cruz River Watershed (SCRW) in the Southern Arizona. The parameters in the CHRE2D model were calibrated by using the rainfall event in July 15th, 1999. Hourly precipitation data from a Regional Climate Model (RCM) called Weather Research and Forecasting model (WRF), for three periods, 1990-2000, 2031-2040 and 2071-2079, were used to quantify the impact of climate change on the magnitude and frequency of flood for the Santa Cruz River Watershed (SCRW) in the Southern Arizona. Precipitation outputs from RCM-WRF model were bias-corrected using observed gridded precipitation data for three periods before directly used in the watershed model. The watershed model was calibrated using the rainfall event in July 15th, 1999. The calibrated watershed model was applied to SCRW to simulate surface flow routing for the selected three periods. Simulated annual and daily maximum discharges are analyzed to obtain future flood frequency curves. Results indicate that flood discharges for different return periods are increased: the discharges of 100-year and 200-year return period are increased by 3,000 and 5,000 cfs, respectively.
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Fernandes, Maria do Rosário Pereira. "Avaliação da composição e estrutura ripária Mediterrânica baseada em SIG e detecção remota." Doctoral thesis, ISA, 2013. http://hdl.handle.net/10400.5/6450.
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Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de AgronomiaRiparian forests are responsible for many functions considered essential to the preservation of the ecological condition of fluvial corridors. The aim of this thesis is to characterize the structural and compositional patterns of the riparian vegetation in relation to its ecological quality using remote detection and geographic information systems. Separability analyses allowed to characterize and distinguish the spectral patterns and divergent optical behavior between the main riparian forests of Portugal. Spectroradiometry analyses enable the identification of the optimal bands for the remote detection of the alien invasive species Arundo donax, giant reed, from the surrounding vegetation, taking into account its seasonal spectral variability. The Geostatistical techniques combined with the application of landscape metrics, in high spatial resolution images, allowed the remote identification of the structural patterns for riparian forests and for the riparian areas invaded by the giant reed. It was obtained a relation between the observed degradation patterns and a gradient of human disturbance in the surrounding areas of fluvial corridors. The combination of the spectral and geometric attributes allowed to increasing giant reed mapping accuracy in riparian habitats, using a semi-automatic technique.
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Dlamini, Mandla E. "An assessment of vegetation condition of small, ephemeral wetlands ecosystem in a conserved and non-conserved area of the Nelson Mandela Bay Metropole." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/4653.
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Wetlands in South Africa are increasingly coming under threat from agriculture and urban development and rapidly disappearing, especially small, ephemeral wetlands. In response to the many threats to wetlands, South Africa has seen an increased interest in wetland research, which has introduced many methods to help standardize the approach to research, management and conservation of wetlands. Remote sensing can be a powerful tool to monitor changes in wetland vegetation and degradation leading to losses in wetlands. However, research into wetland ecosystems has focused on large systems (> 8 ha). Small wetlands (< 2 ha), by contrast, are often overlooked and unprotected due to the lack of detailed inventories at a scale that is appropriate for their inclusion. The main aim of this study was to determine if remote sensing (RS) and Geographical Information System (GIS) techniques could detect changes in small, ephemeral wetlands within areas under different management regimes in the Nelson Mandela Bay Metropole (NMBM) at different time intervals. Further, to explore the potential of hyperspectral remote sensing for the discrimination between plant species and to see if differences could be detected in the same species within two areas different management regimes. Four SPOT satellite images taken within a 6-year period (2006-2012) were analysed to detect land cover land changes. Supervised classification to classify land cover classes and post-classification change detection was used. Proportions of dense vegetation were higher in the conservation area and bare surface was higher outside that conservation area in the metropolitan open space area. Statistical tests were performed to compare the spectral responses of the four individual wetland sites using Normalized Difference Vegetation Index (NDVI) and red edge position (REP) .REP results for conserved sites showed significant differences (P < 0.05), as opposed to non-conserved ones. By implication, wetland vegetation that is in less degraded condition can be spectrally discriminated, than the one that is most degraded. Field spectroscopy and multi-temporal imagery can be useful in studying small wetlands.
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Lamprecht, Adriaan Johannes Hendrikus. "A vegetation study on the area leased for mining purposes by Impala Platinum, Rustenburg South Africa / Adriaan Johannes Hendrikus Lamprecht." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4604.
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Conservation and management of the ecology of natural areas has become a prerequisite for
mining companies in South Africa. Systematic conservation planning provides a useful tool for
land–use planning and impact assessment, particularly in the mining industry. A study was
therefore undertaken to provide sufficient, spatially explicit biodiversity and veld condition
information to aid in the development and establishment of an official conservation plan for the
leased mining area of Impala Platinum. By identifying areas with high plant diversity or
endemism and by assessing veld conditions as well as grazing and browsing capacities,
recommendations could be made towards management strategies and potential future land–use
practices.
The licensed mining area, north of Rustenburg, covers 29334 ha and includes 14 operational
shafts. The area was stratified into three main categories based on landscape types namely:
norite koppies; thornveld and rehabilitated areas. The Braun Blanquet approach was followed to
sample 139 stratified random relevés. Additional computer software packages were used for
capturing, processing and presentation of the phytosociological data (TURBOVEG) as well as a
visual editor for phytosociological tables (MEGATAB). Ordinations were subsequently
performed to confirm the plant communities and illustrate possible environmental gradients,
using multivariate statistic analyses (CANOCO). Four plant communities with two subcommunities
were identified and described in both the norite koppies and thornveld respectively
while three plant communities with three sub–communities were identified in the rehabilitated
areas. Specific environmental factors that influence plant community structure and composition
in the norite koppies were the aspect and percentage of soil surface rockiness while soil types
proved to be the distinguishing factor in the thornveld. The distribution of plant communities in
the rehabilitated areas is mainly due to anthropogenic influences rather than any environmental
factors.
The Fixed Point Monitoring of Vegetation Methodology– FIXMOVE was then used to sample 32
stratified random survey plots in four selected plant communities in order to quantify and
compare veld conditions as well as grazing and browsing capacities. The determination of
landscape functionality served to support these quantitative results. The Landscape Function
Analysis (LFA) method was used for this purpose. Multivariate statistic analyses (CANOCO)
were used to indicate possible degradation gradients between the plant communities.
Conclusions regarding conservation and management units were reached by interpreting the
quantitative data in accordance with the phytosociological results and recommendations could
then be made. All the norite koppies plant communities were recommended as areas for The Fixed Point Monitoring of Vegetation Methodology– FIXMOVE was then used to sample 32
stratified random survey plots in four selected plant communities in order to quantify and
compare veld conditions as well as grazing and browsing capacities. The determination of
landscape functionality served to support these quantitative results. The Landscape Function
Analysis (LFA) method was used for this purpose. Multivariate statistic analyses (CANOCO)
were used to indicate possible degradation gradients between the plant communities.
Conclusions regarding conservation and management units were reached by interpreting the
quantitative data in accordance with the phytosociological results and recommendations could
then be made. All the norite koppies plant communities were recommended as areas for
ii
conservation because of unique and high biodiversity and anthropogenic threats. The Eragrostis
rigidior–Ziziphus mucronata and Acacia caffra–Bothriochloa insculpta Communities in the
thornveld showed the best potential for browsing and grazing practices but were also
recommended for conservation because of their high species diversity and anthropogenic
threats. The high landscape functionality, veld condition and grazing capacity of the Aristida
bipartita–Bothriochloa insculpta Community indicated that the rehabilitation of the opencast
mining areas had been relatively successful at the time of the surveys. Selected parts of the
Indigofera heterotricha–Aristida bipartita Community were also recommended for conservation
and management in the form of controlled and more effective grazing strategies were
recommended for the rest of the thornveld.Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2011.
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Horsnell, Tara Kathleen. "Quantifying thresholds for native vegetation to salinity and waterlogging for the design of direct conservation approaches." University of Western Australia. School of Environmental Systems Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0082.
Full textAbstract:
A field-based project was undertaken to develop and test a mechanism which would allow for the correlation of the health of vegetation surrounding playa lakes in south-west Australia with the natural variation in salinity and waterlogging that occurs spatially and temporally in natural systems. The study was designed to determine threshold ranges of vegetation communities using moderately extensive data over short temporal periods which will guide the design of potential engineering solutions that manipulate hydrological regimes to ultimately conserve and protect native vegetation. A pair of playa lake ecosystems, surrounded by primary production land, was modelled with hydro-geological data collected from March 2006 to March 2007. The data was used to determine the hydroperiods of vegetation communities fringing playa lakes and provide insight into the areas and species that are most affected by extreme rainfall events which are hypothesised to have a significant, rapid deleterious effect on the ecosystems. The methodology was multi-faceted and included; a detailed topographical survey; vegetation surveys; hydrological and hydro-geological monitoring over a 12 month period. 4 The hydro-geological data and vegetation data was linked with the topographical survey at a high resolution for spatial analysis in a Geographic Information System (GIS) to determine the degree of waterlogging experienced by vegetation communities over the monitoring period. The study has found that the spatial and temporal variability of hydroperiods has been reduced by rising groundwater levels, a result of extensive clearing of native vegetation. Consequently populations are becoming extinct locally resulting in a shift in community composition. Extreme summer rainfall events also have a significant impact on the health of vegetation communities by increasing the duration of waterlogging over an annual cycle and in some areas expanding the littoral zone. Vegetation is most degraded at lower positions in the landscape where communities are becoming less diverse and dominated by salt tolerant halophytic species as a result of altered hydrological regimes. Some species appear to be able to tolerate groundwater depths of less than 2.0 m from the surface, however there are thresholds related to the duration at which groundwater is maintained at this depth. Potential engineering solutions include groundwater pumping and diverting water through drains to maintain sustainable hydroperiods for vegetation in areas with conservation value. The effectiveness and efficiency of the engineering solutions can be maximised by quantifying thresholds for vegetation that include sustainable durations of waterlogging. The study has quantified tolerance ranges to salinity and waterlogging with data collected over 12 months but species may be experiencing a transition period where they have 5 sustained irreversible damage that will result in their eventual mortality. With long-term monitoring, the methodology developed and tested in the study can be used to quantify the long-term tolerance ranges that are important for the application of conservation approaches that include engineering solutions.
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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.
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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.
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Makaudze, Ephias M. "Do seasonal climate forecasts and crop insurance really matter for smallholder farmers in Zimbabwe? Using contingent valuation method and remote sensing applications." Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1110389049.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xiii, 155 p.; also includes map, graphics (some col.) Includes bibliographical references (p. 149-155). Available online via OhioLINK's ETD Center
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Mordaunt, Catharine Hilary. "Association between weather conditions, snow-lie and snowbed vegetation." Thesis, University of Stirling, 1998. http://hdl.handle.net/1893/2213.
Full textAbstract:
Snowbed vegetation contains both vascular plants and bryophytes. The latest snowbeds cover areas that are of predominantly, if not exclusively, bryophyte flora while the vascular plants are generally confined to the periphery of such late snowbeds. It is hypothesised that the exclusion of vascular flora from the snowbed core is the result of the shortened growing season generated by late-lying snow, which the bryophyte flora is better able to tolerate. The snowbed bryophytes cannot, however, tolerate the competition offered by the vascular flora in the peripheral areas from which they are absent. Data indicate that some of the bryophyte snowbed species are inhabiting optimal conditions in the snowbed core, rather than tolerating sub-optimal conditions. Adaptation and acclimation responses observed in peripheral vascular species indicate that these are inhabiting sub-optimal conditions in the snowbed periphery. The relationship between snow-lie and climate is examined, with to the construction and examination of a second hypothesis that snowbed loyalty in the Scottish Highlands is high, while duration of snow cover is variable. Snow-lie loyalty is the product of prevailing wind conditions, which are persistent and consistent in Scotland leading to consistency in late snowbed location, while the occurrence of mid-winter thaws at all altitudes makes duration of snow cover through accumulated snow depth much more variable. Increased zonal flow in winter has affected snow-lie in the Scottish Highlands, with a slight decrease in snow-lie duration in recent years. It is not clear whether this pattern applies to all altitudes and accumulations at higher levels, especially in the western Highlands, may be increasing as a result of steeper winter-time lapse rates. With late snowbed location varying very little, it is possible that the consequences of global warming may not necessarily mean an extinction of the late snowbed bryophytes in Scotland, which constitute an important part of Britain's montane flora.
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McElhinny, Chris, and chris mcelhinny@anu edu au. "Quantifying stand structural complexity in woodland and dry Sclerophyll Forest, South-Eastern Australia." The Australian National University. Centre for Resource and Environmental Studies, 2005. http://thesis.anu.edu.au./public/adt-ANU20060322.133914.
Full textAbstract:
In this thesis I present and test a methodology for developing a stand scale index of structural complexity. If properly designed such an index can act as a summary variable for a larger set of stand structural attributes, providing a means of ranking stands in terms of their structural complexity, and by association, their biodiversity and vegetation condition. This type of index can also facilitate the use of alternative policy instruments for biodiversity conservation, such as mitigation banking, auctions and offsets, that rely on a common currency the index value that can be compared or traded between sites. My intention was to establish a clear and documentable methodology for developing a stand scale index of structural complexity, and to test this methodology using data from real stands.¶
As a starting point, I reviewed the literature concerning forest and woodland structure and found there was no clear definition of stand structural complexity, or definitive suite of structural attributes for characterising it. To address this issue, I defined stand structural complexity as a combined measure of the number of different structural attributes present in a stand, and the relative abundance of each of these attributes. This was analogous to approaches that have quantified diversity in terms of the abundance and richness of elements. It was also concluded from the review, that stand structural complexity should be viewed as a relative, rather than absolute concept, because the potential levels of different structural attributes are bound within certain limits determined by the inherent characteristics of the site in question, and the biota of the particular community will have evolved to reflect this range of variation. This implied that vegetation communities with naturally simple structures should have the potential to achieve high scores on an index of structural complexity.¶
I proposed the following five-stage methodology for developing an index of stand structural complexity:
1. Establish a comprehensive suite of stand structural attributes as a starting point for developing the index, by reviewing studies in which there is an established relationship between elements of biodiversity and structural attributes.
2. Develop a measurement system for quantifying the different attributes included in the comprehensive suite.
3. Use this measurement system to collect data from a representative set of stands across the range of vegetation condition (highly modified to unmodified) and developmental stages (regrowth to oldgrowth) occurring in the vegetation communities in which the index is intended to operate.
4. Identify a core set of structural attributes from an analysis of these data.
5. Combine the core attributes in a simple additive index, in which attributes are scored relative to their observed levels in each vegetation community.¶
Stage one of this methodology was addressed by reviewing a representative sample of the literature concerning fauna habitat relationships in temperate Australian forests and woodlands. This review identified fifty-five studies in south-east and south-west Australia, in which the presence or abundance of different fauna were significantly (p<0.05) associated with vegetation structural attributes. The majority of these studies concerned bird, arboreal mammal, and ground mammal habitat requirements, with relatively fewer studies addressing the habitat requirements of reptiles, invertebrates, bats or amphibians. Thirty four key structural attributes were identified from these fifty-five studies, by grouping similar attributes, and then representing each group with a single generic attribute. This set, in combination with structural attributes identified in the earlier review, provided the basis for developing an operational set of stand level attributes for the collection of data from study sites.¶
To address stages two and three of the methodology, data were collected from one woodland community Yellow Box-Red Gum (E. melliodora-E. Blakelyi ) and two dry sclerophyll forest communities Broadleaved Peppermint-Brittle Gum (E. dives-E. mannifera ), Scribbly Gum-Red Stringybark (E. rossii E. macrorhyncha ) in a 15,000 km2 study area in the South eastern Highlands Bioregion of Australia. A representative set of 48 sites was established within this study area, by identifying 24 strata, on the basis of the three vegetation communities, two catchments, two levels of rainfall and two levels of condition, and then locating two sites (replicates) within each stratum. At each site, three plots were systematically established, to provide an unbiased estimate of stand level means for 75 different structural attributes.¶
I applied a three-stage analysis to identify a core set of attributes from these data. The first stage a preliminary analysis indicated that the 48 study sites represented a broad range of condition, and that the two dry sclerophyll communities could be treated as a single community, which was structurally distinct from the woodland community. In the second stage of the analysis, thirteen core attributes were dentified using the criteria that a core attribute should:¶
1. Be either, evenly or approximately normally distributed amongst study sites;
2. Distinguish between woodland and dry sclerophyll communities;
3. Function as a surrogate for other attributes;
4. Be efficient to measure in the field.
The core attributes were: Vegetation cover <0.5m Vegetation cover 0.5-6.0m; Perennial species richness; Lifeform richness; Stand basal area of live trees; Quadratic mean diameter of live stems; ln(number of regenerating stems per ha+1); ln(number of hollow bearing trees per ha+1);ln(number of dead trees per ha+1);sqrt(number of live stems per ha >40cm dbh); sqrt(total log length per ha); sqrt(total largelog length per ha); Litter dry weight per ha. This analysis also demonstrated that the thirteen core attributes could be modelled as continuous variables, and that these variables were indicative of the scale at which the different attributes operated.¶
In the third and final stage of the analysis, Principal Components Analysis was used to test for redundancy amongst the core attributes. Although this analysis highlighted six groupings, within which attributes were correlated to some degree, these relationships were not considered sufficiently robust to justify reducing the number of core attributes.¶
The thirteen core attributes were combined in a simple additive index, in which, each attribute accounted for 10 points in a total index value of 130. Attributes were rescaled as a score from 0-10, using equations that modelled attribute score as a function of the raw attribute data. This maintained a high correlation (r > 0.97, p< 0.0001) between attribute scores and the original attribute data. Sensitivity analysis indicated that the index was not sensitive to attribute weightings, and on this basis attributes carried equal weight. In this form my index was straightforward to apply, and approximately normally distributed amongst study sites.¶
I demonstrated the practical application of the index in a user-friendly spreadsheet, designed to allow landowners and managers to assess the condition of their vegetation, and to identify management options. This spreadsheet calculated an index score from field data, and then used this score to rank the site relative to a set of reference sites. This added a regional context to the operation of the index, and is a potentially useful tool for identifying sites of high conservation value, or for identifying sites where management actions have maintained vegetation quality. The spreadsheet also incorporated the option of calculating an index score using a subset of attributes, and provided a measure of the uncertainty associated with this score.¶
I compared the proposed index with five prominent indices used to quantify vegetation condition or habitat value in temperate Australian ecosystems. These were: Newsome and Catlings (1979) Habitat Complexity Score, Watson et al.s (2001) Habitat Complexity Score, the Site Condition Score component of the Habitat Hectares Index of Parkes et al. (2003), the Vegetation Condition Score component of the Biodiversity Benefits Index of Oliver and Parkes (2003), and the Vegetation Condition Score component of the BioMetric Assessment Tool of Gibbons et al. (2004). I found that my index differentiated between study sites better than each of these indices. However, resource and time constraints precluded the use of a new and independent data set for this testing, so that the superior performance of my index must be interpreted cautiously.¶
As a group, the five indices I tested contained attributes describing compositional diversity, coarse woody debris, regeneration, large trees and hollow trees these were attributes that I also identified as core ones. However, unlike these indices, I quantified weeds indirectly through their effect on indigenous plant diversity, I included the contribution of non-indigenous species to vegetation cover and did not apply a discount to this contribution, I limited the direct assessment of regeneration to long-lived overstorey species, I used stand basal area as a surrogate for canopy cover, I quantified litter in terms of biomass (dry weight) rather than cover, and I included the additional attributes of quadratic mean diameter and the number of dead trees.¶
I also concluded that Parkes et al. (2003), Oliver and Parkes (2003), and Gibbons et al. (2004), misapplied the concept of benchmarking, by characterising attributes in terms of a benchmark range or average level. This ignored processes that underpin variation at the stand level, such as the increased development of some attributes at particular successional stages, and the fact that attributes can respond differently to disturbance agents. It also produced indices that were not particularly sensitive to the differences in attribute levels occurring between stands. I suggested that a more appropriate application of benchmarking would be at the overarching level of stand structural complexity, using a metric such as the index developed in this thesis. These benchmarks could reflect observed levels of structural complexity in unmodified natural stands at different successional stages, or thresholds for structural complexity at which a wide range of biota are present, and would define useful goals for guiding on-ground management.
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Boboulos, Miltiadis A. "Fire spread in low rise vegetation with application to Mediterranean conditions." Thesis, University of Portsmouth, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.478894.
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Barnes, Mallory L., M. Susan Moran, Russell L. Scott, Thomas E. Kolb, Guillermo E. Ponce-Campos, David J. P. Moore, Morgan A. Ross, Bhaskar Mitra, and Sabina Dore. "Vegetation productivity responds to sub-annual climate conditions across semiarid biomes." WILEY-BLACKWELL, 2016. http://hdl.handle.net/10150/616989.
Full textAbstract:
In the southwest United States, the current prolonged warm drought is similar to the predicted future climate change scenarios for the region. This study aimed to determine patterns in vegetation response to the early 21st century drought across multiple biomes. We hypothesized that different biomes (forests, shrublands, and grasslands) would have different relative sensitivities to both climate drivers (precipitation and temperature) and legacy effects (previous-year's productivity). We tested this hypothesis at eight Ameriflux sites in various Southwest biomes using NASA Moderate-resolution Imaging Spectroradiometer Enhanced Vegetation Index (EVI) from 2001 to 2013. All sites experienced prolonged dry conditions during the study period. The impact of combined precipitation and temperature on Southwest ecosystems at both annual and sub-annual timescales was tested using Standardized Precipitation Evapotranspiration Index (SPEI). All biomes studied had critical sub-annual climate periods during which precipitation and temperature influenced production. In forests, annual peak greenness (EVImax) was best predicted by 9-month SPEI calculated in July (i.e., January-July). In shrublands and grasslands, EVImax was best predicted by SPEI in July through September, with little effect of the previous year's EVImax. Daily gross ecosystem production (GEP) derived from flux tower data yielded further insights into the complex interplay between precipitation and temperature. In forests, GEP was driven by cool-season precipitation and constrained by warm-season maximum temperature. GEP in both shrublands and grasslands was driven by summer precipitation and constrained by high daily summer maximum temperatures. In grasslands, there was a negative relationship between temperature and GEP in July, but no relationship in August and September. Consideration of sub-annual climate conditions and the inclusion of the effect of temperature on the water balance allowed us to generalize the functional responses of vegetation to predicted future climate conditions. We conclude that across biomes, drought conditions during critical sub-annual climate periods could have a strong negative impact on vegetation production in the southwestern United States.
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Plakane, Rūta. "Seasonal Variations of Manning’s Coefficient Depending on Vegetation Conditions in Tärnsjö, Sweden." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-325356.
Full textAbstract:
Hydrological models are used widely and they demand for multiple input variables and observations. One of those variables is Manning’s roughness coefficient. In the current literature the variability of the coefficient poses an unknown uncertainty. This study examines a small river channel located in central Sweden, and aims to determine the variability and uncertainty of the roughness coefficient during diverse vegetation conditions within the channel. During multiple field visits to the location, slope, water level and cross-section examination is performed. With numerical simulation, discharge and roughness coefficients are obtained. With the hydraulic model (HEC-RAS), stage-discharge rating curves are produced and extrapolation is applied to obtain high flows. Manning’s roughness coefficients and their uncertainties are assessed by two different approaches. Determining the coefficient in a simplified sensitivity analysis by using Manning’s equation and calibrating HEC-RAS while applying Mean absolute error (MAE) calculation. The calculated roughness coefficients presents higher range when using Manning’s equation (summer vegetation conditions – 0.2, winter vegetation conditions – 0.095). On the contrary MAE provides values closer to each other (summer – 0.15, winter – 0.11). The obtained results indicate a high variance between summer and winter vegetation conditions, producing 38 cm water level differences during high flows using Manning’s equation and 6 cm difference using the calibration of the model in HEC-RAS. These results confirm that the roughness coefficient cannot be assumed to be constant throughout different seasons as had been assumed widely when applying hydrological modelling. Throughout the study innovative approaches and methods (e.g. back-calculating from Manning’s equation and calibrating HEC-RAS based on observed water levels) are used in order to determine the consequences of ignoring the variability of the roughness coefficient. Due to the study, one can derive that vegetation needs to be considered in having an important impact on the varying roughness coefficient value and it cannot be left as a constant value within hydrological models.Hydrologiska modeller är vanligt förekommande för bestämning av vattenföringsprognoser, och kräver ett flertal indata variabler och observationer. En av variablerna är Mannings råhetskoefficient, som orsakar en okänd felmarginal i den hydrologiska modellen. Den här studien syftar till att avgöra osäkerheten av felmarginalen samt variationen av Mannings råhetskoefficient. Det görs genom att undersöka en liten bäck i centrala Sverige vid olika vegetationstillstånd. Flera fältundersökningar genomfördes där tvärsnittsmätningar, vattennivå och hydraulisk gradient bestämdes. Från numerisk simulering kan flöde och råhetskoefficienten kalkyleras. Genom den hydrauliska modellen (HEC-RAS) fås ratingkurvor för vattennivå och flöde, där extrapolering görs för de högre flödena. Mannings råhetskoefficient och dess osäkerhet undersöks med två olika tillvägagångssätt. Den första metoden bygger på att använda Mannings ekvation. Den andra metoden bygger på att först genomföra en kalibrering i HEC-RAS och sedan använda kalkylering av medel-absolut-avvikelse, ”Mean absolute error” (MAE). Råhetskoefficienten beräknad med hjälp av Mannings ekvation ger större spridning (sommar – 0.2, vinter – 0.095) än vid användning av MAE beräkning (sommar – 0.15, vinter – 0.11). Resultatet visar en stor skillnad mellan så kallad vinter och sommar vegetation. Skillnaden i vattennivå är 38 cm vid användning av första metoden och 6 cm vid användning av den andra metoden. Resultaten från den här studien visar att råhetskoefficienten inte kan antas vara stabil under olika säsonger, vilket antas vid hydrologisk modellering. Innovativa metoder, så som bak-kalkylering från Mannings ekvation och kalibrering i HEC-RAS baserad på observerade vattennivåer har används för at bestämma utvärdera konsekvenserna av att ignorera variationen av råhetskoefficienten vid modellering. Den här studien visar att variationen av råhetskoefficienten påverkas av vegetationsförhållandet och att koefficienten inte kan antas konstant för korrekt modellering.
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Samková, Aneta. "Revitalizace vybraného úseku toku Hartmanického potoka." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265329.
Full textAbstract:
Diploma thesis deal with revitalization Hartmanice river in district Svitavy. Section of interest is on 0,400 – 1,234 of river km. Part of this thesis is also rating current condition of stream and his vegetation accompaniment. Rating was made on base of reconnaissance terrain, my own measurement and photo documentation. In diploma thesis was design some revitalization steps: stabilization sink with wooden sills and stabilization slopes by using willow fences and similar precautions. There was designed total change of flow trend. Rating of current condition and condition of modified stream was made in software HEC-RAS.
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Dong, T. T. Trang. "Chemical composition and toxicity of emissions from burning five vegetation types of Western Australia under experimental combustion conditions." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2019. https://ro.ecu.edu.au/theses/2180.
Full textAbstract:
This study investigated the emission factors (EFs) for inorganic gases (CO2, CO, SO2, NO and NO2), carbonyls (formaldehyde, acetaldehyde, acetone, propionaldehyde, butyraldehyde and benzaldehyde), volatile organic compounds (VOCs) and particulate matter (PM2.5 and PM10) from laboratory-based fires of vegetation from five typical vegetation types of Western Australia. Species burnt were three grasslands (Spinifex represented by Triodia basedowii, Kimberley grass represented by Sehima nervosum and Heteropogon contortus, and an invasive grass represented by Ehrharta calycina (Veldt grass)), Banksia woodland and Jarrah forest under different combustion conditions. Chemical composition (water-soluble metals and polycyclic aromatic hydrocarbons – PAHs) and in vitro toxicity of PM2.5 were also measured. Vegetation samples were burnt in a ceramic chamber in varying combustion conditions altered by controlling the vegetation moisture content (<10%, 12–16% and 20–25%) and the air flow rate (0, 1.25 and 2.94 m.s-1). Burns of woodland (Banksia) and forest (Jarrah) had significantly higher EFs for CO, SO2 and PM2.5 compared with those from grassland (Spinifex). Emissions of temperate grass (Veldt) fires were significantly different from those of the tropical grass (Spinifex and Kimberley grasses), with lower EFCO2 and higher EFs for CO, carbonyls and PM2.5. EFs for SO2, NO and NO2 were variable between different vegetation types, indicating variation in the nitrogen and sulphur content of the fuels. The EFs for most carbonyls were similar between most vegetation types, with the exception of Veldt grass. Functions which may be useful to predict emissions of infrequently measured carbonyls (acetaldehyde, acetone and propionaldehyde) from the EF for formaldehyde, a commonly measured and reported substance, were also proposed. Fifteen VOCs were identified in the smoke, but concentrations were too low to be quantified. Benzene, toluene, styrene and indene were the most frequently detected VOCs.
Moisture content did not strongly influence the modified combustion efficiency (MCE) and EFs for gaseous pollutants, but significantly affected the EF for PM2.5 with higher emissions from burns of moister vegetation. Increasing the air flow rate significantly increased the emissions of most pollutants. However, combustion conditions did not strongly affect the PM2.5 chemical composition.
The MCE, EFs for CO and CO2 results in this study were similar to values reported from field measurements for similar vegetation types in Australia, indicating the applicability of these laboratory-based results. Emission factors were different to the profiles generated from vegetation fires in other parts of the world.
Toxicity of PM2.5 on human lung epithelial (A549) cells was assessed using cell viability and cytokine production measurements. Responses on cell viability were associated with K and Na concentrations in PM2.5, whilst the cytokine production of cells was more affected by the PM2.5-bound PAH, Al, Cu and Mn concentrations. Toxicity between vegetation types was different, which might be due to the differences in chemical composition of PM2.5. PM2.5 emitted from Jarrah burns appeared to have the highest toxicity on epithelial cells, followed by those from Banksia, Veldt grass and Spinifex. The findings of this study on toxicity of PM2.5 demonstrate the adverse impact on human health of particulate from bushfires and emphasise the importance of vegetation type on toxicological outcomes of bushfire-derived PM2.5.
The EFs obtained in this study can be used in models to estimate the emissions from bushfires in Australia, particularly Western Australia. Results on toxicity of PM2.5 provide information for relevant government agencies to preliminarily evaluate the risk to human health, especially for firefighters and communities in close proximity to bushfire events.
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Daly, Fiona Frances Margaret. "The effect of diet on the nutrition and production of merino ewes in the arid shrublands of Western Australia." Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/570.
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For the Arid Shrublands of Western Australia (WA) knowledge is limited on what sheep eat and how nutritious their diets are. A study was undertaken on two stations near Yalgoo (28º18’S 116º38’E) in WA, from November 2005 to December 2007. Station 1 (28º39’S 116º18’E) used a flexible rotational grazing management system (RGS), moving 3000-4000 Merino sheep every 3 – 6 weeks through a choice of 20 paddocks. Station 2 (28º18’S 116º42’E) used a flexible continuous grazing management system where small mobs (500 sheep) stayed in paddocks all year, until shearing. Two paddocks on Station 2 were chosen to represent paddocks with high (CGS-G) and low (CGS-P) feed value.A total of 300 Merino hogget (18 months old) ewes were randomly selected from the stations. One hundred and fifty sheep from each station were selected and separated into three mobs of 50 sheep by stratifying live weights. The selected sheep were allocated to either of the two paddocks on Station 2 or the single rotating mob on Station 1. Therefore there were a total of 100 sheep, 50 from each station, on each of the two paddocks on Station 2 and the one rotating mob on Station 1.Throughout the study period sheep live weights, body condition scores (BCS) and wool production were measured and related to plant photosynthetic activity (derived from Normalised Difference Vegetation Index - NDVI), and dietary energy, protein and digestibility (determined from faecal NIRS calibrations). A DNA reference data bank of some common native plant species was established and then used as a library to identify plant species in sheep faeces and thus provide information on variations in diet composition over the study period. Plant nutritional content was also measured and compared to climatic changes and sheep nutrition.Over the study period Merino ewe live weights, wool production, faecal samples and native plant leaf material were collected and analysed from each of the three management treatments (RGS, CGS-G, CGS-P). Wool production measurements included wool length, strength and fibre diameter, including position of breaks, minimum and maximum diameter along the staple of midside samples. Oven dried plant and faecal samples were ground and subsequently analysed for proximate composition. Plant samples were further analysed for mineral contents and 24 h in vitro gas production (GP) using the rumen buffer gas fermentation technique. Organic matter digestibility (OMD) and metabolisable energy (ME) content of the plants were determined using 24 h net gas production. Faecal near infrared reflectance spectroscopy (fNIRS) calibrations, developed by Curtin University of Technology and ChemCentre WA, were used to predict the nutritional attributes of sheep diets.Sheep production was found to be affected by rainfall, seasons, management and differing blood lines. In 2006, live weights, BCS and wool fibre diameter increased in response to high summer rainfall. Lower rainfall in 2007 resulted in variable, but generally less animal production with lower live weights, BCS and wool fibre diameter. Management decisions to avoid mating in 2006 on CGS; and agistment for sheep on RGS at the end of 2006 resulted in better sheep production results. Sheep originally sourced from Station 2 generally had higher live weights than sheep sourced from Station 1, suggesting a difference in bloodlines.Faecal DNA provided useful information regarding diet selection and diversity of sheep grazing on the Arid Shrublands of WA. Of the species that were DNA profiled, the sheep ate Acacia saligna, Aristida contorta, Atriplex spp., Enchylaena tomentosa, Frankenia sp., Ptilotus obovatus, Rhagodia eremaea and Scaevola spinescens in 2006 whilst in 2007; the sheep consumed A. saligna, A. contorta, Atriplex spp., Eremophila forrestii, Enneapogon caerulescens, Frankenia spp., Maireana spp., Ptilotus obovatus, Rhagodia eremaea, Solanum lasiophyllum and Stipa elegantissima. However, there were 28 amplified bands in 2006 and 51 in 2007 that did not conclusively match any of the reference plant species. This indicates that the sheep were consuming diets that contained more species than what was analysed in this study. Faecal DNA results indicated a decrease in the diversity of the diets selected by the sheep during summer, which coincided with a decrease in animal production.Native plants were found to be low in OMD and ME, but high in crude protein (CP), and variable in mineral content. Sheep were able to select diets adequate in OMD, ME and CP for maintenance requirements, and low in tannins and phenolics, although continuous drought conditions resulted in reduced production, indicating that the sheep were not getting adequate nutrition to meet their growth requirements. The use of fNIRS provided more useful information about the quality of the diet of the sheep than nutritionally profiling individual plants. NDVI was found to be related to dietary OMD and wool fibre diameter changes along the staple.Overall, the effects of management seemed to be secondary to the effects of climate on sheep production and nutrition. The statistical accuracy of results was low; however, the use of advanced technologies to explore relationships between climate, plant nutritional profiles and animal production and nutrition has provided an expansion of knowledge of sheep nutrition in the region. This extra knowledge may help land owners in the region to make more sustainable management decisions concerning livestock management and grazing pressures on native pastures.
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Van, der Heyden Francois. "An investigation of photosynthetic C-fixation in fynbos growth forms and its variation with season and environmental conditions." Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/17725.
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Bibliography: pages 162-177.The seasonal and diurnal patterns of photosynthetic gas exchange and the water relations of seven species of the mediterranean-climate region of South Africa (fynbos) were investigated. The following species, representing the major fynbos elements, were chosen for intensive investigation: Erica plukenetii and Erica hispidula (ericoid element), Thamnochortus lucens and Askidiosperma paniculatum (restioid element), Protea laurifolia and Leucadendron salignum (proteoid element). Metrosideros angustifolia, a shrub of riparian habitats, was also studied.
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Woldu, Zerihun. "Variation in grassland vegetation on the central plateau of Shewa, Ethiopia in relation to edaphic factors and grazing conditions /." Vaduz : J. Cramer, 1985. http://catalog.hathitrust.org/api/volumes/oclc/12384853.html.
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Zengeni, Rebecca. "Assessing soil carbon and carbon dioxide effluxes under different vegetation cover conditions in the Eastern Cape Province, South Africa." Thesis, Nelson Mandela Metropolitan University, 2013. http://hdl.handle.net/10948/d1018676.
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Albany thicket is prevalent in the Eastern Cape Province of South Africa. Its spread has diminished through overgrazing and heavy browsing by animals, land clearance and urban expansion. The result is highly degraded land characterized by invasion of alien species. There is a wealth of documented evidence on the high carbon sequestration ability of thicket biome, but not much has been done to assess its effect on carbon dioxide emissions from the soil. Given that the concentration of atmospheric greenhouse gases has been constantly rising since the industrial era, it is imperative to assess the influence of thicket biome as a source or sink of these gases. There is evidence of shifts in the climate in southern Africa as reflected by changes in rainfall patterns, increased temperatures, recurrent droughts and fires. As such, the historical rainfall variability in an Albany thicket region and its interaction with the temporal land use / cover changes was studied. This served to give some background information about the study area for more detailed study on C and carbon dioxide effluxes in thicket vegetation under different levels of degradation. This study thus aimed to determine the influence of thicket vegetation at various levels of degradation on soil carbon and carbon dioxide fluxes. The impact of plant photosynthetic pathway on soil C residence time and gas effluxes were analysed to elucidate on the land-use and cover patterns occurring in the area. All this was done to shed some light on the role of soil and thicket vegetation on carbon dioxide emissions and C storage in the spectrum of a shifting climate. The main area of research was Amakhala reserve in an Albany thicket in Eastern Cape Province; and it concentrated on three land cover types namely intact thicket, degraded thicket and grassland. The objectives mentioned above were achieved by assessing historical rainfall variability from 1970 to 2010 through trend and time series analysis at nine rainfall stations located at Amakhala reserve, Grahamstown, Bathurst, Port Alfred, Uitenhage and Port Elizabeth. The land use changes that have occurred in the Albany thicket region covering Amakhala reserve, Grahamstown, Bathurst and Port Alfred were also assessed for 1989, 1999 and 2009 through satellite image analysis with Idrisi Andes GIS software; then their interaction with rainfall variability were determined. To elucidate on the vegetation species composition and land use / cover changes that have occurred in the study area, plant biomass as well carbon (C) and nitrogen (N) isotope measurements were done. Plant biomass was assessed for the dominant species through use of pre-existing allometric equations that required data on plant basal diameter, canopy area, stem numbers and height. The plant carbon was then estimated through use of a conversion factor of 0.48 on above-ground biomass, while soil organic C was determined through the modified Walkely - Black method. Carbon and N isotope ratios were determined from the foliar material of three replicate samples of dominant plant species then analyzed through mass spectrometry. Soil carbon dioxide effluxes were then monitored in each of the intact thicket (IT), degraded thicket (DT) and grassland (G) over a 10 month period; by measuring the net carbon dioxide exchange rate (NCER) through the dynamic chamber method. An automated carbon dioxide exchange analyzer, coupled to a soil temperature probe and photosynthetic active radiation (PAR) sensor was used; with NCER measurements taken every 20-30 days. Soil temperature, moisture, penetration resistance and PAR readings were taken during each assay and later used to interpret the NCER. Results showed that long term variability in annual rainfall had a declining trend at Grahamstown (r = -0.59), Uitenhage and Bathurst stations (r = -0.32 at both stations), but was not significant at Amakhala, Port Alfred and Port Elizabeth stations. Most reductions in rainfall occurred in the 1980s and 1990s with the autumn, winter and summer rainfalls, the daily rainfall index and the daily rainfall subclasses of 10 mm and above showing a similar trend. The land use change detection gave a significant increase in proportion of degraded and transformed (moderately degraded) land between 1989 and 2009 with most of the increases occurring from 1989 to 1999, while farmland area decreased by 1.8 percent over the years. Thus the Albany region had over 30 percent of its land occupied by transformed vegetation, with heavy browsing and uncontrolled grazing being attributed to the destruction of pristine vegetation. Land-use change to game ranching and goat pastoralism was attributed to the reduction in farmland. Rainfall variability – land use change linkages were most significant in 1999 that recorded the least rainfall and had the lowest mean, maximum and sum of the NDVI. Grahamstown had the most significant rainfall-NDVI trends as it had the lowest NDVIs in 1999 when rainfall was lowest, the highest NDVI in 1989 when rainfall was highest and moderate NDVIs in 2009 when rainfall was moderate. Vegetation at the IT was characterized by a dense thicket with diverse growth forms of canopy trees, woody shrubs, succulent shrubs and ephemerals which mostly had the C3 type of pathway. This was in contrast with the IT soil isotopy that showed more positive C isotope ratios, indicating a switch between C3 and CAM photosynthesis in original vegetation. Most of the canopy trees had disappeared in the DT to be replaced by herbs, shrubs and grasses. As such, there was a huge difference in isotope ratios between DT plants and soils with the plants having mostly C3 metabolism while the soil showed a predominance of CAM plants in previous vegetation, indicating significant changes in land cover. The G site mostly comprised the grasses Themeda triandra and Panicum maximum and a few herbs. It maintained a dominance of C4 metabolism in both plants and soils showing very little change in species composition over the years. Because of the higher species diversity at IT, its soil organic C was quite high reaching levels of 3.4 percent (i.e. 3.4 t C / ha) in the top 10 cm then decreasing with depth (p < 0.001); but was moderate at DT (1.1-1.3 percent) and very low at G ( 0.5 percent C) (p < 0.001). In the same manner above-ground biomass was highest at IT i.e. 330 000 kg/ha; but was only 22 000 kg/ha in DT and as low as 6 700 kg/ha in G vegetation. High biomass at IT was mostly attributed to the succulent shrub Portulacaria afra and the canopy trees Euclea undulate, Rhus longispina and Schotia afra. This above-ground biomass translated to biomass C amounts of 158 000 kg/ha at IT, 10 600 kg/ha at DT and 3 200 kg/ha at G. Thus the IT had the highest while G the least and DT moderate plant and soil C sequestration ability. In all, the conversion of IT to DT led to a net loss of 147 000 Kg of biomass C / ha and 12 000kg less organic C / ha of land. Soil carbon dioxide effluxes were however variable between seasons as they were affected by differences in soil properties and seasonal weather patterns. High soil moisture levels (up to 16 percent gravimetric moisture) resulted in reduced soil penetration resistance (1 to 4 Kg/cm2) which raised effluxes at G and DT sites (up to 1.2 μmols m-2 sec-1) in winter, while low moisture (2 percent) resulted in hard dry soil (14 Kgm-2 penetration resistance) with suppressed CO2 effluxes in spring (0.2 μmols m-2 sec-1) especially in DT and G soils. Rising temperature generally caused accelerated gas emissions but only when moisture was not limiting (as was the case in IT). Thus the high summer temperatures (up to 40oC) gave lower effluxes especially in DT and G (< 1 μm-2sec-1) due to limited moisture supply (< 10 percent); while the Autumn period that had very high temperature (up to 48 oC) and good moisture (up to 16 percent) saw accelerated soil CO2 emissions (averaging 2 μmols m-2 sec-1) from all cover types. The high biomass and litter fall at IT served as ready substrate for soil respiration as long as moisture was not limiting and temperatures were favourable, while reduced cover at DT resulted in poor moisture conservation and creation of hard dry soils in spring and summer with reduced respiration. It was concluded that the DT had high CO2 effluxes in winter and reduced emissions in summer; while the opposite was true for the IT. All the cover types had minimal CO2 effluxes in spring and accelerated emissions in autumn. The grassland on the other hand was a fairly moderate source or sink of CO2 in most seasons compared with the other two covers. It was observed that an environment of good moisture and low-moderate temperatures (such as that in the winter) minimises effluxes while maintaining good plant productivity. It was concluded that thicket vegetation is a good sink of carbon that should be preserved in its natural condition to optimize its carbon sequestration potential. All three land covers served as sources or sinks of CO2 depending on soil and seasonal conditions. Thus high moisture and low penetration resistance generally increased effluxes of thicket ecosystems. The effect of increasing temperature on effluxes was only significant when moisture was not limiting. Conditions of good moisture and low-moderate temperatures gave reasonable amounts of effluxes while maintaining good plant productivity. Though the dry soil conditions significantly reduced effluxes in all land covers; they were not desirable since they decreased plant productivity and ultimately its C sequestration potential. Moreover, prolonged dry conditions only serve to exacerbate recovery of thicket plants as they increase mortality of canopy species in degraded and transformed areas in comparison with intact thicket.
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Šebesta, Radek. "Studie možností revitalizačních opatření příměstského vodního toku." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226135.
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This diploma thesis deals with the problem of river restoration. Selected watercourse, which was inappropriately technically modified, had been mapped in detail and land use map was compiled. The watercourse was divided into sections, which were described in detail and assessed for suitability for restoration action. The new nature-friendly channel was designed on the selected section of the watercourse. Technical graphic documentation was designed.
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Gradowski, Tomasz Aleksander. "The influences of geoclimatic site conditions, disturbance type and canopy composition on the composition of understorey vegetation of boreal mixedwoods." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58807.pdf.
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Schofield, Darci A. "Vegetation Dynamics and Tree Radial Growth Response in Harvest Gaps, Natural Gaps, and Closed Canopy Conditions in Maine's Acadian Forest." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/SchofieldDA2003.pdf.
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Dunham, Natasha Robin. "Influence of hydrological and environmental conditions on mangrove vegetation at coastal and inland semi-arid areas of the Gascoyne region." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2014. https://ro.ecu.edu.au/theses/1406.
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Mangrove stands are uncommon within semi-arid climates and rare within inland systems. It is uncertain whether the same environmental variables influence mangroves growing in a semi-arid climate as the trees growing in tropical and sub-tropical areas. Field studies conducted on the ecophysiological responses of the mangrove species Avicennia marina are few; however hydrological regimes are considered the key factor influencing mangrove stand zonation, structure and individual tree growth. The Gascoyne region of Western Australia provides a unique opportunity to investigate whether mangroves growing within an inland semi-arid environment display similar growth patterns and ecophysiological responses to their coastal counterparts.
This study investigates the distribution, structure and condition of the mangrove A. marina growing at Lake MacLeod and coastal and riverine stands near Carnarvon, Western Australia. Hydrological categories based on freshwater inputs, tidal influences, distance from permanent water sources and sediment elevations were used to investigate the environmental conditions present within specific hydrological regimes. Mangrove tree responses to environmental conditions were evaluated by assessing above-ground biomass, shoot production, water-use efficiency, photosynthesis, specific leaf area, weight and total chloride content. The overarching objective was to determine the environmental factors influencing the presence, morphology and physiological state of A. marina growing at inland, coastal and riverine sites in a semi-arid climate.
Soil moisture content, organic matter content, average and seasonal range in sediment EC, and distance from the permanent water sources were found to influence vegetation characteristics at Lake MacLeod. Soil moisture content was highest close to permanent ponds and at lower sediment elevations. Sediment salinity was highest close to pond edges, although the majority of the lake bed is hypersaline due to high evapoconcentration. The environmental gradients are complex at Lake MacLeod as a result of the unique hydrological regime. Seawater supply to permanent ponds is constant via an underground karst system which enters the lake through vents and seepages present along the western edge of the lake bed. It is evident that the constant supply of marine water is the key environmental factor supporting mangrove presence and structure. Average mangrove tree height, basal area, density and canopy cover are greatest near the permanent ponds. Mangrove density and height was also high, though patchy away from the ponds where saline seepages occurred. A high density of stunted mangroves was found on lake shorelines receiving periodic saline flooding via wind surges. Samphire cover was also greatest close to the permanent ponds, demonstrating that both mangrove and Samphire presence and importance is influenced by consistency of water availability.
Sediment conditions were significantly different between inland and coastal sites, with sediment salinity and moisture content higher at Lake MacLeod. The ecophysiological responses displayed by A. marina in different categories of hydrological regimes revealed that consistency of water supply, irrespective of salinity, is an important driver of long and short-term productivity, water-use efficiency, leaf size and weight, and tree height. In general, short and long-term production was inversely proportional to distance from permanent water sources, although it was highly variable due to seepages away from the permanent ponds. Mangrove trees growing at the landward edge of coastal sites were the most water-use efficient (~ -28 δ¹³C), relative to the inland Lake MacLeod trees (~ - 26 δ¹³C), and was directly linked to water supply not quality. Photosystem health in trees growing at both the riverine stands (yield 0.66 ± 0.01) and inland stands found at greater distances from ponds (yield 0.065 ± 0.02), were significantly lower than all other trees in this study. Relative maximum electron transfer rate was also significantly lower at these sites, suggesting that the riverine trees were affected by other stresses such as herbicides. Mangrove trees near permanent water sources, or that received tidal flushing, displayed larger leaves and lower specific leaf weight, indicating that A. marina has the ability to not only tolerate hypersaline conditions but also acclimate to harsh and variable conditions via changes to ecophysiological responses and morphology.
This research has developed a better understanding of how A. marina persists at Lake MacLeod and whether these trees are under greater stress as opposed to the mangroves growing at coastal stands. Sediment conditions between coastal and inland sites were significantly different, but it was distance from permanent water sources that influenced mangrove stand features. Therefore, the key environmental variable influencing distribution, structure and ecophysiological state of A. marina growing in a semi-arid climate is predominantly water availability.
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Alaibakhsh, Masoomeh. "Digital change detection and separation of anthropogenic and natural impacts on ecohydrological conditions in the Pilbara region, WA." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2017. https://ro.ecu.edu.au/theses/1951.
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A deficiency in crucial digital data, such as vegetation cover, in remote regions is a challenging issue for sustainable water management and planning, especially for areas undergoing rapid development, such as mining in the Pilbara, Western Australia. This is particularly relevant to Inflow and Groundwater Dependent Vegetation (IGDVs) (riparian vegetation and groundwater dependent vegetation) which provide important ecological services and, as such, require regional protection. However, such invaluable assets experience changes over time due to either human activities such as land development or natural phenomena such as climate change or fire events.
The main objectives of this research was to 1) advance an approach to delineate inflow dependent ecosystems at a local scale; 2) adopt it to map the assets at regional scale using remotely sensed data (Landsat 5 TM imagery due to its appropriate temporal and spatial resolution for historical studies, 1986-2011), ground-truth data and available information such as reports, digital layer and climate data; 3) develop a method for identification and quantitative assessment of IGDVs changes and attribution of the changes to particular impacts or stressors, and 4) apply the developed change detection method to investigate and evaluate impacts of an adopted water resource management options on inflow dependent assets in the Pilbara.
Outcomes of the research exposed that the proposed delineation method allowed production of accurate inflow dependent ecosystems maps for the Pilbara bioregion. The change detection method was also effective in detecting various spatial and temporal scales of changes and separating anthropogenic and natural impacts. It was further discovered that climate has had significant impacts on the assets of the area.
The finding and information produced from this research is capable to aid government, industry and communities to consider the environmental, social, cultural and economic aspects of the sustainable use, development and management of land and water resources in arid and semiarid Pilbara, WA and areas with similar ecohydrological conditions. Four papers were prepared from the research, two are published and two are under review.
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Ju, Shu. "Model of Strategies of Tree Carbon Allocation to Roots, Foliage and Defense in Relation to Environmental Conditions." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/377.
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Three general questions are studied regarding plant carbon allocation strategies. (1) The R* Rule states that the superior competitor in a plant community should exclude all others by minimizing available limiting nutrient concentration below the level needed for survival of its competitors. I asked whether a plant carbon allocation strategy that minimizes the concentration of available limiting nutrient is consistent with Lotka's (1922) conjecture that ecosystems should evolve to maximize total energy flow (primary production). (2) In landscapes such as the Everglades, areas of landscape with higher energy flow (primary production) than the surrounding area also have higher available concentrations of limiting nutrient, rather than lower concentrations, which might be expected from the R* rule. I asked whether this pattern can be explained. (3) I asked how optimal allocation of carbon to plant defense allocation strategies might depend on different conditions of nutrient availability, shading, and herbivory. To address all three questions, I used a model revised from the G'DAY model (Comins and McMurtrie 1993) to study tree allocation of carbon resources between foliage, roots, and defense. With regard to the first question, I found that the allocation strategy that leads to minimum concentration of available nutrients is the same as the strategy for which energy flux to roots, rather than total energy flux, is maximized. Further, I found that the strategy that was competitively dominant was neither the strategy for which total energy flux was maximized, nor that for which available nutrient concentration was minimized. With regard to the second question, I found that, if a patch of vegetation on a landscape is able to capture nutrients from the surrounding landscape, for example, through relatively higher evapotranspiration, it could lead to the opposite of what is expected from the R* rule; that is, available limiting nutrient concentration is maximized when carbon flow to the roots is maximized. With regard to the last question, I found that under high herbivory, the optimal plant strategy for allocation of carbon to defense depends on the available nutrient concentration and amount of radiation to the plant, in agreement with some theoretical predictions.
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Федорченко, Б. Л. "Досвід створення лісових культур Сосни звичайної в ДП Чернігівське лісове господарство." Thesis, Чернігів, 2020. http://ir.stu.cn.ua/123456789/20258.
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Федорченко, Б. Л. Досвід створення лісових культур Сосни звичайної в ДП Чернігівське лісове господарство / Б. Л. Федорченко; керівник роботи Чмель O. П.; Національний університет «Чернігівська політехніка», кафедра аграрних технологій та лісового господарства. – Чернігів, 2020. – 71 с.Випускна кваліфікаційна робота присвячена проблемі вирощування лісових культур як засобу лісовідновлення у різних лісорослинних умовах та впливу деревних та чагарникових порід на них. Створення лісових культур потребує врахування відповідності деревної породи типу лісорослинних умов, агротехнічних методів та інших факторів, які впливають на приживлюваність та ріст молодих культур лісових порід.
Graduation qualification work is devoted to the problem of growing forest crops as a means of reforestation in different forest conditions and the impact of trees and shrubs on them. The creation of forest crops requires taking into account the compliance of the tree species with the type of forest vegetation conditions, agronomic methods and other factors that affect theтsurvival and growth of young forest crops.
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Федорченко, Б. Л. "Проект створення культур Сосни звичайної в ДП «Чернігівське лісове господарство»." Thesis, Чернігів, 2021. http://ir.stu.cn.ua/123456789/25120.
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Федорченко, Б. Л. Проект створення культур Сосни звичайної в ДП «Чернігівське лісове господарство» : випускна кваліфікаційна робота : 205 «Лісoве гoспoдарствo» / Б. Л. Федорченко ; керівник роботи М. М. Селінний ; НУ "Чернігівська політехніка", кафедра аграрних технологій та лісового господарства. – Чернігів, 2021. – 61 с.Випускна кваліфікаційна робота «Проект створення культур Сосни звичайної в ДП Чернігівське лісове господарство» присвячена проблемі створення лісових культур як засобу лісовідновлення у різних лісорослинних умовах та впливу деревних та чагарникових порід на них. Створення лісових культур потребує врахування відповідності деревної породи типу лісорослинних умов, агротехнічних методів та інших факторів, які впливають на приживлюваність та ріст молодих культур лісових порід.
Graduation qualification work "The project of creating crops of Scots Pine in the State Enterprise "Chernihiv Forestry" is devoted to the problem of growing forest crops as a means of reforestation in different forest conditions and the impact of trees and shrubs on them. The creation of forest crops requires taking into account the compliance of the tree species with the type of forest vegetation conditions, agronomic methods and other factors that affect the survival and growth of young forest crops.
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Adam, Hassan Elnour. "Integration of remote sensing and GIS in studying vegetation trends and conditions in the gum arabic belt in North Kordofan, Sudan." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-67657.
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The gum arabic belt in Sudan plays a significant role in environmental, social and economical aspects. The belt has suffered from deforestation and degradation due to natural hazards and human activities. This research was conducted in North Kordofan State, which is affected by modifications in conditions and composition of vegetation cover trends in the gum arabic belt as in the rest of the Sahelian Sudan zone. The application of remote sensing, geographical information system and satellites imageries with multi-temporal and spatial analysis of land use land cover provides the land managers with current and improved data for the purposes of effective management of natural resources in the gum arabic belt. This research investigated the possibility of identification, monitoring and mapping of the land use land cover changes and dynamics in the gum arabic belt during the last 35 years. Also a newly approach of object-based classification was applied for image classification. Additionally, the study elaborated the integration of conventional forest inventory with satellite imagery for Acacia senegal stands. The study used imageries from different satellites (Landsat and ASTER) and multi-temporal dates (MSS 1972, TM 1985, ETM+ 1999 and ASTER 2007) acquired in dry season (November). The imageries were geo-referenced and radiometrically corrected by using ENVI-FLAASH software. Image classification (pixel-based and object-based), post-classification change detection, 2x2 and 3x3 pixel windows and accuracy assessment were applied. A total of 47 field samples were inventoried for Acacia senegal tree’s variables in Elhemmaria forest. Three areas were selected and distributed along the gum arabic belt. Regression method analysis was applied to study the relationship between forest attributes and the ASTER imagery. Application of multi-temporal remote sensing data in gum arabic belt demonstrated successfully the identification and mapping of land use land cover into five main classes. Also NDVI categorisation provided a consistent method for land use land cover stratification and mapping. Forest dominated by Acacia senegal class was separated covering an area of 21% and 24% in the year 2007 for areas A and B, respectively. The land use land cover structure in the gum arabic belt has obvious changes and reciprocal conversions between the classes indicating the trends and conditions caused by the human interventions as well as ecological impacts on Acacia senegal trees. The study revealed a drastic loss of Acacia senegal cover by 25% during the period of 1972 to 2007.The results of the study revealed to a significant correlation (p ≤ 0.05) between the ASTER bands (VNIR) and vegetation indices (NDVI, SAVI, RVI) with stand density, volume, crown area and basal area of Acacia senegal trees. The derived 2x2 and 3x3 pixel windows methods successfully extracted the spectral reflectance of Acacia senegal trees from ASTER imagery. Four equations were developed and could be widely used and applied for monitoring the stand density, volume, basal area and crown area of Acacia senegal trees in the gum arabic belt considering the similarity between the selected areas. The pixel-based approach performed slightly better than the object-based approach in land use land cover classification in the gum arabic belt. The study come out with some valuable recommendations and comments which could contribute positively in using remotely sensed imagery and GIS techniques to explore management tools of Acacia senegal stands in order to maintain the tree component in the farming and the land use systems in the gum arabic belt.
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Shields, Erin C. "Influences of Habitat Conditions on Submerged Aquatic Vegetation Development in the Chickahominy River and Other Virginia Tributaries of the Chesapeake Bay." W&M ScholarWorks, 2008. https://scholarworks.wm.edu/etd/1539617869.
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Recently, there has been an expansion of submerged aquatic vegetation (SAV) in the tidal fresh and oligohaline portions of lower Chesapeake Bay tributaries. Much like the resurgence seen in the Potomac in the 1980’s, this spread of SAV in Virginia systems such as the Mattaponi, Pamunkey and Chickahominy seems to have been initiated by the introduction and spread of the invasive species Hydrilla verticillata, and appears to have been rapid. However the resurgence in the Piankatank has occurred in the absence of the introduction of this species. The factors that are influencing the growth of SAV in these tributary environments, including water quality and habitat conditions as well as the potential for interspecific competition between H. verticillata and the other SAV species in these regions are not well known. Annual aerial mapping surveys of the Chickahominy River were used alongside historical water quality data to investigate the patterns and rates of SAV bed development, and the relationships between this development and water quality conditions. Field investigations were performed in order to better understand the seasonal community dynamics relative to water quality conditions and interspecific competition. Historical analysis, field monitoring and field experimentation all showed salinity and turbidity to be the main factors controlling SAV abundance and species distribution along the Chickahominy River. Historical analysis of the Chickahominy River revealed a decline in SAV abundance in 2002, which corresponded with seasonal mean salinities of 4.1 psu. SAV abundance from 1998-2007 showed a significant correlation with vegetation emergence period secchi depth, in which secchi depths of 0.3 meters, the lowest of the time period, occurred during the 2002 SAV decline. Field data showed species zonation, in which H. verticillata was the overall dominant species, but was limited to the upper portion of the river where salinity intrusion remained below 2 psu throughout the growing season. Najas minor was dominant in the lower portion of the river where salinities reached over 4 psu in October. Salinity was the best predictor for H. verticillata’s biomass difference between the upper and lower river. SAV in the Chickahominy was able to grow in a wide range of conditions, with total suspended solids and chlorophyll a concentrations at times greater than 20 mg l-1 and 40 μg l-1, respectively, and sediment organic content ranging from less than 1% to greater than 25%. Comparisons with the Mattaponi and Piankatank rivers revealed ideal habitat for H. verticillata growth in the Mattaponi, where salinities along the vegetated reach of the upper river did not extend above 1 psu. On the other hand, this species was not found growing in the Piankatank, where salinities in the very upper portion of the river reached 3.5 psu. Finally, a field species removal experiment demonstrated that environmental conditions rather than interspecific competition were most important in determining plant performance, as both H. verticillata and N. minor exhibited poor growth in the lower river site, which had higher salinity and turbidity levels than the upper river site.
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Hurst, Mark Kiyoshi. "A Comparison of Ecological Conditions and Relationships in an Altered Wetland and an Unaltered Wetland." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3161.
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The purpose of the study is to identify and quantify the hydrologic and ecologic differences between two adjacent sections of Colt Creek; one section unaltered and one section altered by clearing and drainage. These differences were measured by monitoring water levels, groundcover vegetation in each of the two areas, and monitoring numbers and species of birds utilizing the two areas. Surface water levels were measured in three locations: in the historic Colt Creek flow way, in the ditch draining the creek, and in an adjacent wetland strand. In addition, a shallow monitor well in the creek was used to measure groundwater levels when the creek was dry. The intent of avian monitoring was to use birds as a relatively easily observable surrogate for wildlife habitat utilization in general. Groundcover vegetation species and approximate percent cover data were recorded at several locations in both wetlands. Data collection occurred from January 2010 to January 2011.
The results indicate that the hydrology, vegetation, and avian utilization of the two adjacent areas were substantially different. Specifically, the hydroperiod during the monitoring period was seven weeks shorter in duration in the downstream area than in the upstream unaltered area. In addition, the presence of flowing water, i.e., stream flow, through the downstream area was approximately 18 weeks less than the upstream area. Vegetation species composition, diversity, and percent cover also differed in the two areas. A total of 39 groundcover species were identified in the two sites. Seven (7) additional plants were identified to genus. Twenty one species (74.9 %) of all plants identified were common to both areas. Sixteen species (41.0 %) were found only in the unaltered site and 10 species (25.6 %) were found only in the altered site. Species richness was greater in the unaltered site while percent cover was less, i.e., more bare ground / plant litter. Relative percent cover by wetland species in the unaltered site was 11.8 percent greater than in the altered site. Finally, avian utilization was greater in the altered area, as 484 individual birds and 27 species were identified in the altered site compared to 138 individual birds and 13 different species identified in the unaltered area.
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Shandas, Vivek. "Towards an integrated approach to urban watershed planning : linking vegetation patterns, human preferences, and stream biotic conditions in the Puget Sound lowland /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/10824.
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Pringle, Keara Louise. "An Internship with the Ohio Environmental Protection Agency, Division of Surface Water: Understanding the Vegetation and Soil Conditions in Natural Riparian Forests." Miami University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=miami149333522985015.
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He, Chen [Verfasser]. "Role of roadside vegetation as a passive method for urban air particulate matter absorption and its capturing efficiency under different conditions / Chen He." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2020. http://d-nb.info/1205878505/34.
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Bhattacharjee, Nilanjana. "Hyperspectral and Multispectral Image Analysis for Vegetation Study in the Greenbelt Corridor near Denton, Texas." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5328/.
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In this research, hyperspectral and multispectral images were utilized for vegetation studies in the greenbelt corridor near Denton. EO-1 Hyperion was the hyperspectral image and Landsat Thematic Mapper (TM) was the multispectral image used for this research. In the first part of the research, both the images were classified for land cover mapping (after necessary atmospheric correction and geometric registration) using supervised classification method with maximum likelihood algorithm and accuracy of the classification was also assessed for comparison. Hyperspectral image was preprocessed for classification through principal component analysis (PCA), segmented principal component analysis and minimum noise fraction (MNF) transform. Three different images were achieved after these pre-processing of the hyperspectral image. Therefore, a total of four images were classified and assessed the accuracy. In the second part, a more precise and improved land cover study was done on hyperspectral image using linear spectral unmixing method. Finally, several vegetation constituents like chlorophyll a, chlorophyll b, caroteoids were distinguished from the hyperspectral image using feature-oriented principal component analysis (FOPCA) method and which component dominates which type of land cover particularly vegetation were correlated.
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Dias, Chrislene Nojosa. "Strawberry crop under different conditions of environments and biofertilizer doses the region of Massif de Baturite, CearÃ." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11880.
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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel SuperiorIn the Brazilian scenario Strawberry culture is presented as an alternative crop , because it fits in regions of temperate , subtropical and tropical climate, and is an important production chain , from an economic and social perspective. The cultivation in protected environment emerged as an ally in creating a more favorable microclimate production, controlling climate variations at different locations and times of planting. Allied to the environment, fertilization via biofertilizer doses, may contribute to nutrition, establishment and growth of strawberry production. In this approach, the biofertilizer has been presented as an alternative that has been adopted in agriculture as an option of reusing waste without proper destination in the properties. In this context, we conducted a job in the Experimental Farm of the University of International Integration Lusophone African- Brazilian ( UNILAB ), located at Sitio PiroÃs, municipality of RedenÃÃo, CearÃ, in the Massif Baturite, from September 2013 to January 2014, with the objective of evaluating the effects of different cultivation environments and doses of biofertilizer on growth, nutrition, yield and quality of strawberry Oso Grande, and generate technology to be diffused over the handling of the strawberry crop conditions edaphoclimatic of the Massif Baturite region. The experiment was conducted in randomized complete block design with split plot design with four replications. The plots consisted of two cropping systems (under greenhouse and field craft) and subplots consisted of five doses of liquid biofertilizer equivalent to 0, 400, 800, 1200, 1600 mL plant - 1 week - 1. Climatic characteristics of the site, nutritional soil and leaf tissue as a function of different doses of biofertilizer, and still vegetative characteristics of productivity and quality were analyzed. The strawberry crop in greenhouse conditions handmade showed highest yield (10.734 kg ha - 1), in relation to cultivation in open field (9.629 kg ha - 1). The biofertilizer can be used as a source of nutrients in the cultivation of strawberries in open field conditions, cultivar Oso Grande, meeting the demands of culture. The nutrient content in soil and leaves showed significant increases with the application of doses of biofertilizer, contributing to the health of plants. The vegetative characteristics of plants and post- harvest fruit grown in open field conditions showed higher values compared to cultivation in greenhouse condition artisanal, indicating that the temperature and luminosity affects such characteristics. The strawberry crop at conditions of the Massif Baturite - Cearà in months with milder temperatures get higher productivity.
No cenÃrio brasileiro a cultura do Morangueiro apresenta-se como uma alternativa de cultivo, pois se adapta em regiÃes de clima temperado, subtropical e tropical, e representa uma importante cadeia produtiva, do ponto de vista econÃmico e social. O cultivo em ambiente protegido desponta como um aliado na criaÃÃo de um microclima mais favorÃvel a produÃÃo, controlando variaÃÃes climÃticas em diferentes locais e Ãpocas de plantio. Aliado ao ambiente, a adubaÃÃo via doses de biofertilizante, pode contribuir para a nutriÃÃo, estabelecimento e incremento produtivo do morangueiro. Nesse enfoque, o biofertilizante tem se apresentado como uma alternativa que vem sendo adotada na agricultura como opÃÃo de reaproveitamento de resÃduos sem destinaÃÃo adequada nas propriedades. Neste contexto, foi conduzido um trabalho na Ãrea da Fazenda Experimental da Universidade da IntegraÃÃo Internacional da Lusofonia Afro-Brasileira (UNILAB), localizada no SÃtio PiroÃs, municÃpio de RedenÃÃo, CearÃ, no MaciÃo de BaturitÃ, no perÃodo de setembro de 2013 a janeiro de 2014, com o objetivo de avaliar os efeitos de diferentes ambientes de cultivo e de doses de biofertilizante no crescimento, nutriÃÃo, produtividade e qualidade do morangueiro Oso Grande, e gerar tecnologia, para ser difundida, sobre o manejo do cultivo do morangueiro nas condiÃÃes edafoclimÃticas da regiÃo do MaciÃo de BaturitÃ. O experimento foi conduzido no delineamento em blocos ao acaso no esquema de parcelas subdivididas, com quatro repetiÃÃes. As parcelas foram constituÃdas de dois sistemas de cultivo (sob telado artesanal e a campo aberto) e as subparcelas foram constituÃdas por cinco doses de biofertilizante lÃquido equivalentes a 0, 400, 800, 1200, 1600 mL planta-1 semana-1. Foram analisadas as caracterÃsticas climÃticas do local, nutricionais do solo e do tecido foliar em funÃÃo das doses diferenciadas de biofertilizante, vegetativas e ainda caracterÃsticas de produtividade e qualidade. O cultivo do morangueiro em condiÃÃes de telado artesanal apresentou maior produtividade (10.734 kg ha-1), em relaÃÃo ao cultivo em campo aberto (9.629 kg ha-1). O Biofertilizante pode ser utilizado como fonte de nutrientes no cultivo do morango em condiÃÃes de campo aberto, cultivar Oso Grande, atendendo as exigÃncias da cultura. Os teores de nutrientes no solo e nas folhas apresentaram incrementos significativos com a aplicaÃÃo de doses de biofertilizante, contribuindo para a sanidade das plantas. As caracterÃsticas vegetativas das plantas e de pÃs-colheita dos frutos cultivados em condiÃÃes de campo aberto apresentaram maiores valores em relaÃÃo ao cultivo em condiÃÃo de telado artesanal, indicando que a temperatura e a luminosidade afeta tais caracterÃsticas. O cultivo do morangueiro nas condiÃÃes edafoclimÃticas do MaciÃo de BaturitÃ-Cearà em meses com temperaturas mais amenas, obterà maior produtividade.
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Davies, Althea Lynn. "High spatial resolution Holocene vegetation and land-use history in West Glen Affric and Kintail, Northern Scotland." Thesis, University of Stirling, 1999. http://hdl.handle.net/1893/2020.
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Small peat basins (c. 10-50 m diameter) were used to obtain fine spatial resolution pollen-stratigraphic records of Holocene vegetation and land-use history in upland West Glen Affric and adjacent lowland Kintail, north-western Scottish Highlands. These data provide evidence for remarkably diverse and dynamic early to mid-Holocene vegetational mosaic and sustained later Holocene upland land-use. While acidophilous Pinus sylvestris-Betula-Calluna vulgaris communities on lower hillslopes appear comparable with other areas of the Highlands, data from floodplain and alluvial fan sediments in West Affric indicate a greater woodland diversity. Betula-dominated alluvial woods included a species-rich mix of arboreal, fen, tall-herb and ruderal herbaceous taxa, with Pinus forming small populations, confined to marginal soils. Ulmus was an important component of the lowland Betula-Alnus woods. Spatial differences in soil forming processes, particularly nutrient and base status, played a primary role in determining community composition, structure, dynamics, species diversity and stability. Inferred climatic shifts during the mid-Holocene, initially to drier, more continental conditions, followed by increased oceanicity, are suggested to have made woodland communities increasingly vulnerable to low intensity grazing disturbance and anthropogenic interference during the later Neolithic and early Bronze Age. These stresses resulted in widespread woodland decline, including that of Pinus, with the spread of blanket peat and heath on poorer hillside soils, and grassland communities on alluvial sediment. Bronze Age agricultural expansion is followed by several phases of expansion and/or intensification, with sustained pastoral and arable activity in the lowlands and on small 'islands' of richer soils in the uplands. There is little evidence for abandonment and the longevity of agricultural activity, particularly cultivation, above 250 m OD clearly indicates that the unqualified assumption of upland marginality is inappropriate. The implications for the interpretation of land-use in the Highlands from conventional palynological and archaeological records are discussed. The level of spatial and temporal detail regarding the palaeoecology of plant communities and adaptive land management evident in the present study is not afforded by conventional pollen analyses. This suggests that fine-spatial resolution palynology has the potential to contribute previously unrecognised information at scales which are directly applicable to ecological and human understanding and which can be more successfully integrated with neoecological and archaeological research, fostering closer collaboration between the disciplines.
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Miller, Jacob William. "Utility of Macrophyte Habitat for Juvenile Fishes: Contrasting Use in Turbid and Clearwater Conditions of Maumee Bay, Lake Erie." Bowling Green State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1434633926.
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