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Madsen, Matthew David. "Measurement of Fine Spatial Scale Ecohydrologic Gradients in a Pinyon-Juniper Ecosystem." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/24.
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With the dramatic expansion of pinyon-juniper woodlands over the last century, improved understanding of how these woodlands modify infiltration properties is needed, in order for land managers to make informed decisions on how to best manage their specific resources. However, current methods for measuring soil infiltration are often limited by low sample sizes and high experimental error, due to constraints associated with remote, non agricultural settings. This thesis first presents a scheme for automating and calibrating two commercially available infiltrometers, which allows collection of a large number of precise unsaturated infiltration measurements in a relatively short period of time. Secondly, a new method to precisely determine saturated hydraulic conductivity from small intact soil cores collected in the field is demonstrated. This method removes bias due to measurement error using a multiple head linear regression approach. Finally, hundreds of fine spatial scale measurements of soil sorptivity, unsaturated hydraulic conductivity, saturated hydraulic conductivity, soil water content, and other soil descriptive measurements along radial line transects extending out from the trunk of juniper (Juniperus osteosperma) and pinyon pine (Pinus edulis) trees. Within the subcanopy of these trees, interactions among litter material, root distributions, and hydrophobic soil significantly influence ecohydrologic properties by limiting and redirecting infiltration below the soil surface. Consequently, hydrophobicity appears to be a mechanism that promotes survival of woody vegetation in arid environments, through decreasing evaporation rates from the soil surface. We further demonstrate how differences in unsaturated infiltration and soil water content between the subcanopy and intercanopy zones are not discrete. Unsaturated infiltration was significantly lower within the subcanopy than in the intercanopy, and increased by eight-fold across a gradient extending outward from near the edge of the canopy to approximately two times the canopy radius. This gradient was not strongly related to soil moisture. In the intercanopy, increasing structural development of biological soil crust cover beyond this gradient was positivity correlated with infiltration capacity. Consequently, these results indicate that the spatial location of the trees should be considered in the assessment and modeling of woody plant and biological soil crust influence on infiltration capacity in a pinyon-juniper ecosystem.
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Scholtz, Olivia Ingrid. "Inter-continental patterns in the fine-scale spatial ecology of rain forest termites." Thesis, University of Plymouth, 2010. http://hdl.handle.net/10026.1/293.
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In this thesis I describe fine-scale spatial patterns in rain forest termites, from the colony to the assemblage level, sampled from one hectare plots in Central African and South East Asian lowland rain forest. By so doing the ecological interactions that structure this functionally important and abundant soil community were identified. The African termite assemblage, dominated by soil-feeding termites, saturated the upper soil profile (collected from 90% of soil pits). In contrast termites were collected from <50% of soil pits in Asia, with this difference reflecting the lower species densities and abundances of soil-feeding termites in Asian forests. Territoriality and inter-specific competition was shown to be important between colonies of soil-feeding species in the African plot. The termite assemblages were spatially associated with several environmental properties. However these could not explain the spatial patterns in the functional components of the assemblages. Wood-feeding termites were highly patchily distributed, due to the heterogeneous nature of their food material, but also due to possible competitive interactions for this. Humus-feeding termites were homogenously structured, due to the continuous nature of soil as their feeding and nesting material. True soil-feeding termites, unique to the African assemblage, were heterogeneously distributed despite the equally continuous nature of their feeding and nesting material. This structure may arise from facilitative interactions, such as co-operative defence against ant predation which may be intense in African systems, or through the transfer of soil material at different stages of decomposition. Competition for space is apparent in both regions, both at the colony level among soil-feeding genera, and between aggregations of functional groups. Positive and negative biotic interactions, operating at various spatial and functional scales, appear to be important in influencing how assemblage composition is spatially structured. If indeed facilitation is important in maintaining the taxonomic and functional diversity in termite assemblages, it would be valuable to confirm the mechanism(s) that drives this (i.e. predation and/or food transfer), as these may then influence ecosystem stability.
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Burrell, Jennifer L. "The Development and Utilization of Fine-scale Methods to Track Neighborhood ChangesCase Study of Youngstown, Ohio." Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1562369777781882.
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Mackay, Jane Louise. "The extraction of urban land cover information from fine spatial scale earth observation data." Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410960.
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Squires, Robert Berry. "A Longitudinal Comparison of Fine Scale Environmental Risk Factors and Waterborne Bacterial Presence in Haiti." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1529494397372641.
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Cobbold, Stephanie M. "The Role of Fine-Scale Habitat Associations in Structuring Spider Assemblages: Determinants of Spatial Patterns In Community Compostion." DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1206.
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Elucidating the ecological determinants of community structure and how they vary spatially has a long history in ecology, but there still is no consensus on the mechanisms behind diversity patterns. The primary objective of this dissertation was to focus on spider assemblages to investigate how the fine-scale habitat associations of organisms may drive their community composition at larger scales. Research was conducted in the Bear River Mountains, Utah, in an attempt to elucidate the potential role of species-microhabitat associations in driving three well-known patterns of community composition that have typically been investigated at broad scales: 1) elevation gradients of species diversity, 2) the response of species assemblages to neighboring habitat structure and 3) community composition at the edges of habitat patches. Slope aspect was a significant predictor of spider density and species richness when communities were compared at the same elevation, suggesting that fine-scale topographic variables may play an important role in shaping elevational patterns of species composition. Cursorial spider composition was strongly linked to site temperature only, whereas differences across web spider assemblages significantly increased with dissimilarities in woody plant cover and temperature. The study on the effects of neighboring habitat structure revealed markedly reduced cursorial spider densities in shrubs without surrounding structure, and more cursorial species in control shrubs, whereas web spiders lacked any significant response to treatments. These contrasting responses indicate that data should be collected at larger spatial extents for mobile species, and that mobility may mediate the outcome of surrounding habitat modifications on the local composition of communities. In the last study, I focused on communities in which the edge-dwelling spiders Theridion and Dictyna strongly differed in terms of concealment and substrate generalization and found that microhabitat choice may affect the sensitivity of species to habitat geometry, a characteristic associated with habitat fragmentation. This work suggests that a better understanding of the links between the biological traits of species and their fine-scale environmental requirements may help uncover the mechanisms behind spatial patterns of community composition at larger scales.
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Sullivan, Timothy J. Jr. "A Fine-scale Analysis of Spatial and Temporal Population Genetic Patterns in the Yellow Perch (Perca flavescens)." University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1364396992.
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Corrales, Duque Carolina. "Population Genetic Structure of Black Grouse (Tetrao tetrix) : From a Large to a Fine Scale Perspective." Doctoral thesis, Uppsala universitet, Institutionen för ekologi och genetik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-150117.
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Black grouse (Tetrao tetrix) is a bird species with a lek mating system found in the Palearctic boreal taiga. It is assumed that it has a continuous distribution along Scandinavia and Siberia, whereas in Central Europe it has declined during the last decades. The primary objective of this thesis was to obtain a deeper understanding of the history, systematic classification and the genetic structure of black grouse on different geographical scales using microsatellites and control region mtDNA sequences (CR). I determined how much the mating system, habitat fragmentation and historical population processes have influenced the partitioning of genetic diversity in this species. Phylogeographical results are consistent with a demographic population expansion, and the patterns of postglacial dispersal suggest that a glacial refugium was located somewhere in central Asia, and from there black grouse spread out to Europe following the retreat of glacial ice sheets. I suggest that the two European black grouse subspecies, T. t. Tetrix and T. t. britannicus correspond to only one subspecies: T. t. tetrix, and that this lineage has diverged from T.t. viridanus, a subspecies found in Kazakhstan. The British population is significantly divergent from the remaining Eurasian samples for microsatellites but it is not for mtDNA. Therefore, they should regard as a separate Management Unit and not as a subspecies. Furthermore, British black grouse occur in three independent genetic units, corresponding to Wales, northern England/southern Scotland and northern Scotland. There was also genetic structure within Sweden. Habitat fragmentation is the main cause of population genetic structure in southern Swedish black grouse. In contrast, low levels of genetic differentiation and high connectivity were found in northern Sweden due to female-biased dispersal. On a finer geographical scale, I found genetic differences between leks due to a mixture of related and unrelated individuals within leks. However, mean relatedness values hardly differed from zero. Some leks were similar to one another and I interpret this as a result of variation in local reproductive success and philopatry. These factors would cause genetic structuring but this by itself would not reveal that kin selection is operating within black grouse leks.
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Brown, Jason K. "Spatial Distribution of Freshwater Mussels (Unionidae) in Ohio Brush Creek Watershed, Southern Ohio." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1289590778.
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Benard, Rebecca Balogh. "Causes and consequences of spatial aggregation for seedling establishment of a long-lived desert perennial shrub (Chrysothamnus nauseosus: Asteraceae) : interaction between intrinsic properties of individuals and fine-scale environmental heterogeneity /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Skalak, Katherine Joanne. "Fine-grained channel margin deposits in a typical gravel bed river spatial and temporal controls on the distribution, quantity, and residence time and implications for centennial-scale sediment and mercury cycling /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 437 p, 2009. http://proquest.umi.com/pqdweb?did=1885693201&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Heban, Thomas Edward. "Representations of Scale and Time: Reinterpreting Cinematic Conventions in Digital Animation to Create a Purposeful Visual Language." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1430399136.
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Lopez-Gallego, Cristina. "Effects of habitat degradation on the evolutionary dynamics of populations in a rainforest cycad (Gymnospermae)." ScholarWorks@UNO, 2007. http://scholarworks.uno.edu/td/555.
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In addition to habitat loss and fragmentation, habitat degradation can have important consequences for biodiversity and population persistence, including effects on ecological and genetic processes beyond decreased demographic viability and the loss of genetic variation. Particularly interesting is the potential for evolutionary changes and adaptation to degraded habitats, that can affect population viability even in the short-term. Here, I explore how environmental changes after habitat degradation affect the evolutionary dynamics of populations of the rainforest cycad Zamia fairchildiana, specifically how habitat degradation affects gene dispersal, inbreeding, directional selection, and genotype-by-environment interactions, and the potential for genetic differentiation between populations. Colonies of Z. fairchildiana showed little genetic differentiation in neutral molecular markers across study sites, thus can be considered as subpopulations. Subpopulations in the disturbed habitat are experiencing different environmental conditions when compared to subpopulation in their native habitat. Disturbed-habitat subpopulations showed a faster life-history. This faster life history is associated with a weaker spatial genetic structure and higher levels of inbreeding in the disturbed-habitat subpopulations. In addition, higher light availability in the disturbed habitat seems to be a major agent of selection on traits like leaf production that have the potential to respond to selection in these subpopulations. Different traits were under selection in the native-habitat subpopulations, suggesting the potential for genetic differentiation between native and disturbed-habitat subpopulations. Genotype by environment interactions in seed germination and seedling survival, in response to light and water availability, further suggested that subpopulations can adaptively diverge between habitats, but the relative role of genetic and environmental factors, particularly maternal effects, on the magnitude and rate of genetic differentiation between subpopulations remains to be evaluated. These results suggest that habitat degradation can have important consequences for the evolutionary dynamics of populations of this cycad, not necessarily typical of habitat loss and fragmentation. This study identified factors and processes important for population persistence in degraded habitats, but population responses to habitat degradation are complex. Thus further studies and long-term experiments are required for better understanding the effects of habitat degradation on population viability.
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Miller, Aileen Kilpatrick. "Site Selection by Migratory Shorebirds in Oregon Estuaries Over Broad and Fine Spatial Scales." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/443.
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Many migratory shorebirds rely on estuaries as stop-over sites to refuel during migration, and the loss of stop-over sites is a primary threat to shorebird populations on the West Coast of the United States (e.g. Calidris alpina pacifica, C. mauri). Conservation and research has focused on the largest of these sites; however, smaller estuaries also host thousands of migratory shorebirds. Furthermore, the reasons for site selection are largely unknown. Estuarine inter-tidal microhabitats are non-uniform and both abiotic and biotic factors may serve as predictors of whether an abundance of shorebirds will use a site. I investigated shorebird site selection on broad and fine scales within Oregon estuaries. To identify factors that relate to shorebird abundance on large spatial scales, I compiled shorebird abundance data from estuaries throughout the Pacific Northwest as well as data on site quality factors. To investigate site selection on a finer scale I measured shorebird abundance, habitat characteristics, and food resources―invertebrates and a newly considered source, biofilm―within two Oregon estuaries during the fall migration period. Finally, I examined whether channels are preferentially used by foraging Calidrid shorebirds by conducting observations during the spring migration. I investigated whether channels may be superior foraging habitat possibly because prey are more abundant, are found at shallower depths, or because sediments are more penetrable (increasing the opportunity for shorebird probing) by taking infauna cores and measuring force required to probe in the sediment at channel and open mudflat sites. Among estuaries, shorebird densities in spring were best predicted by estuary size, as opposed to the amount of any one habitat. During fall migration, the amount of grassland in the surrounding watershed was also a good predictor, pointing to the probable importance of roost sites as well as feeding grounds. The amount of infauna also related to the density of shorebirds using a site. Within estuaries, shorebird distribution in the inter-tidal region was not generally predicted by prey abundance. Channels were used preferentially by shorebirds, and infauna abundance along channels was greater than in the surrounding mudflats. The more penetrable sediments of the channel also made it easier for shorebirds to probe and capture prey. Identification of these large-scale and fine-scale factors that influence site quality for migratory shorebirds will assist land and wildlife managers' efforts to protect these species.
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Allen, Jennifer C. "Species-Habitat Relationships for the Breeding Birds of a Longleaf Pine Ecosystem." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/31670.
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At the Fort Bragg Military Installation, an army base in North Carolina, the habitat associations for the breeding bird species and the effects of the current prescribed fire program on the avifauna are virtually unknown. Fort Bragg encompasses one of the largest, fire-dependent longleaf pine systems existing today and is a mosaic of forested habitats. I used bird count data collected during 1994-1997 at 50-m fixed radius point count stations to examine bird species-habitat relationships in relation to fire treatment (i.e., fire intense longleaf pine woodlands versus fire suppressed mixed pine-hardwood and hardwood forests) and a riparian-upland habitat gradient, and at multiple spatial scales (i.e., the microhabitat and landscape). I used two-way factorial analyses to test for the effects of fire treatment and the riparian-upland habitat gradient on total bird abundance, species richness, and species relative abundance. To examine species-habitat associations at multiple spatial scales, I measured vegetation characteristics at a 50-m radius microhabitat scale, and I quantified landscape structural attributes at a 300-m to 1500-m radius landscape scale using a GIS database and the spatial analysis program FRAGSTATS. I then used logistic regression to determine which microhabitat and landscape variables were associated with the probability of occurrence for each species and which spatial scale was of greater relative importance to a species' occurrence. Finally, I tested logistic regression (LR) models and multiple linear regression (MLR) models, specific to the microhabitat scale, with independent data to evaluate their usefulness at predicting the occurrence and relative abundance for several breeding bird species.
Total bird abundance did not vary across fire treatment and species richness may be only slightly greater in fire suppressed habitats, even though this habitat offered greater structural complexity than the park-like longleaf pine, fire intense habitats. Both total bird abundance and species richness were highest within the riparian habitat of streamhead pocosins, which offered distinctive vegetative characteristics otherwise lacking in this landscape. The fire treatment and riparian-upland habitat gradient also were greatly associated with the relative abundance of many species. Four bird species assemblages were defined based on the relative abundance patterns across fire treatments and the riparian-upland gradient: longleaf pine, fire suppressed, drain (i.e., riparian habitat), and generalist assemblages. Continued longleaf pine restoration using growing season prescribed fire likely will cause a decline in species of the fire suppressed assemblage in mixed pine-hardwood and hardwood forests, including many Neotropical migrant songbirds, but will greatly benefit members of the longleaf pine assemblage, such as the Red-cockaded Woodpecker, Brown-headed Nuthatch, Prairie Warbler, and Bachman's Sparrow.
Breeding bird distributions in this fire-influenced, forest-dominated system were associated with attributes at both microhabitat and landscape spatial scales, though microhabitat attributes generally were of greater importance for the occurrence of most species. Microhabitat variation associated with the fire management gradient (intensely burned habitat versus fire suppressed habitat) and the riparian-upland gradient were the most frequent predictors in the species-habitat models. These results are similar to other studies documenting that microhabitat features were more influential than landscape features for birds in a naturally patchy or forest-dominated landscape.
The microhabitat LR (probability of occurrence) models performed best in presence/absence classification when tested with the same data used for model development (cross-validation tests), and the LR and MLR (relative abundance) models performed better for an independent two-year data set compared to an independent one-year data set (validation tests). Although most MLR models were not significantly biased when tested with an independent two-year data set, these models had relatively low precision, suggesting they can be used to predict species relative abundance across a large area but they may not be sensitive to changes in abundance at individual count stations. These model validation results suggest that modeling species occurrence, rather than both occurrence and relative abundance, would have been sufficient to describe general species-habitat associations and to produce reliable, predictive models sensitive to changes in microhabitat structure and composition.<br>Master of Science
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Shehu, Bora [Verfasser]. "Improving the rainfall nowcast for fine temporal and spatial scales suitable for urban hydrology / Bora Shehu." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2021. http://d-nb.info/1229615024/34.
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Polles, Fiorella Lucia. "Properties of the interstellar medium of the star-forming galaxy, IC10, at various spatial scales." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS276/document.
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Les propriétés du milieu interstellaire (MIS) influencent fortement l’environnement et les processus menant à la formation d’étoiles qui, à son tour, dicte l’évolution d’une galaxie. Les galaxies naines du Groupe Local sont de parfaits laboratoires pour comprendre comment le contenu en métaux (ou métallicité) du MIS affecte l’interaction entre le gaz, la poussière et les étoiles. Mon travail de thèse porte sur les propriétés physiques des régions HII et du gaz diffus ionisé de la galaxie naine IC10, de métallicité 1/3 solaire. La proximité de cette galaxie (d=700kpc) permet l’analyse du MIS à différentes échelles spatiales: des nuages brillants compacts (25pc) au corps entier de la galaxie formant des étoiles (650pc). Afin de mesurer les propriétés physiques du MIS, j’ai modélisé les raies d’émission en infrarouge observées avec Spitzer et Herschel grâce à des modèles de photoionisation et de photodissociation. Je présente une exploration complète de plusieurs méthodes pour déterminer, de manière la plus fiable et selon les contraintes disponibles, les propriétés du MIS à diverses échelles. J’ai contraint les propriétés des nuages compacts les plus brillants dans IC10 et montré que l’émission à plus grande échelle (300pc) est dominée par celle de ces nuages. Enfin, je démontre le besoin d’un modèle à plusieurs composantes pour reproduire les observations dans leur ensemble<br>The properties of the Interstellar Medium (ISM) strongly influence the environment and processes that lead to star-formation, which in turn, drives the evolution of a galaxy. Dwarf galaxies in the Local Group are perfect laboratories to investigate how the metal-poor ISM affects the interplay between gas, dust and stars. In this thesis, I investigate the properties of the HII regions and the diffuse ionized gas of the nearby dwarf galaxy IC10, which has a metallicity of 1/3 solar. Its proximity (d=700 kpc) enables the analysis on different spatial scales: from the compact clumps (~25 pc) to the whole star-forming body of the galaxy (~650pc). In order to measure the physical properties of the ISM, I model the infrared emission lines observed with Spitzer and Herschel with photoionization and photodissociation models. I present an extensive exploration of different methods to determine the most reliable ISM properties, based on the available constraints. I determined the properties of the brightest star-forming clumps within the galaxy and show that the emission at large scales (~300 pc) is dominated by that of the compact, bright clumps that lie within the region. I further demonstrate the need for a multi-component model to fully reproduce the observations
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Keating, Brian Elliott 1968. "Prescribed fire and ecosystem management: Managerial considerations for longer temporal and broader spatial scales." Thesis, The University of Arizona, 1995. http://hdl.handle.net/10150/278497.
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Ecosystem management is positioned as the modern paradigm of resource management. Fire management activities within the natural resource management agencies, under the adoption of an ecosystem management approach, supports an increased focus upon prescribed and manager-ignited fire programs. A review of past national fire policies and the effects they have had upon ecosystem conditions today further supports the role for prescribed fire. Under an ecosystem management approach, resource managers need to consider the effects of fire management activities over longer temporal and broader spatial scales. Examining the ecological, social, political, and economic aspects surrounding fire management activities on these scales will help ensure healthier ecosystems in perpetuity. Although the suppression of wildfires will remain a necessary component to fire management activities today, there needs to be an increased effort to reintroduce fire into ecosystems and to recognize fire as a natural component vital to maintaining ecosystem health.
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Hacioglu, Cigdem. "Spatial Requirements Of Fire Stations In Urban Areas: A Case Study Of Ankara." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612761/index.pdf.
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Fires, with their sudden appearance and destructive character, cause property losses beside much more death and injury especially in cities. Providing fire safety is a multi-faceted context that is related with staff, vehicle, equipment, function, organization, technology, education and consciousness. These are related, indirectly, with spatial organization that is the other side of the issue: they affect space or they are affected from space. In research context, the fire stations are evaluated as a unit of emergency and land use element of urban space. By associating the concepts related to emergency management and to urban scale, the space-time relation is examined in urban areas. This research bases on the spatial deficiencies of fire stations in urban areas which are reasons of the fire losses. Level of laws and regulations in Turkey for spatial requirements are examined. Site selection and design criteria of fire stations are evaluated with available information about implications in Ankara case study. As a result of the interviews that have been made to top executive of fire station, it is found that process of site selection and design of fire stations is going on with subjective experiences in urban space. In conclusion of the research, it is displayed that the decisions about the site selection and design of the fire stations are related to not only population criterion, but also many issues in macro-meso-micro scales. It is considered that the set of multi-criteria that are reached in this regard will provide contribution in legal organization and developing the standards.
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Butler-Cowdry, Sophia. "Investigating the influence of fine-scale physical processes on the spatio-temporal distribution of marine megavertebrates off southwest UK." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/384566/.
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The primary aim of this PhD research is to describe environmental controls on distribution patterns of free-ranging marine top predators in tidally-dominated coastal waters off southwest UK, at a spatial resolution of metres to hundreds of metres, and a temporal resolution of hours to months. As human impacts increase in the nearshore zone (e.g. wet renewables), the need to better understand such fine-scale controls on distribution is critical, particularly as highly mobile marine megavertebrates in southwest coastal waters are amongst some of the region’s most threatened species (e.g. basking sharks Cetorhinus maximus, harbour porpoises Phocoena phocoena, and the critically-endangered Balearic shearwater Puffinus mauretanicus). Current policy drivers (e.g. Marine Protected Area designation and management) require the development of appropriate low-cost methodologies for land-based data collection, in order to provide robust scientific evidence on fine-scale habitat use of these threatened species. To improve understanding of how the physical environment influences habitat use of vulnerable marine predators, a complementary and multi-disciplinary suite of techniques for data collection and analyses was developed. This methodological ‘toolbox’ included: a theodolite to collect highly-accurate (<50 m) positions of animals at sea; acoustic data loggers to collect continuous, subsurface echolocation data on cetacean presence; fine scale (1-m) resolution seafloor bathymetry; novel radar-derived sea surface metrics; and temporally highly-resolved (30-min) met-ocean data (e.g. weather and tides). These data were integrated into statistical predictive models to identify significant drivers of distribution; information that can be used to inform local policy at the study sites and provide new knowledge on the target species. To test the utility of the methods, two contrasting locations of different physical habitat were selected as study sites: the tidally-swept, high-energy, bedrock-dominated Runnel Stone Reef off the southwest tip of the UK mainland; and St Ives Bay, a shallow, sediment-dominated, gently-sloping bay on the northwest Cornish coast. Both sites are known ‘hotspots’ for top predators, and both have an urgent requirement for species’ distribution data to meet current and future management requirements. Theodolite sightings data were collected at both study sites for a variety of small cetaceans and seabird species. All target species were influenced by small-scale topographic features at the scale of metres to tens of metres, with areas of steeper slopes and strong tidal flows (i.e. tidal-topographic fronts) forming particular hotspots. At St Ives Bay, shallow sheltered nearshore habitats were preferentially utilised. Small-scale commercial fishing activity showed significant overlap with target species’ distributions, highlighting the additional importance of these sites for human predators. Significant relationships with tidal flow parameters (e.g. current direction and tidal range) provided further insights into the physical processes driving these clustered sightings. Acoustic data collected from the Runnel Stone Reef provided valuable supporting data on porpoise and dolphin activity, including a strong diel pattern and fine-scale spatial variation in habitat use that was species-specific. The importance of accounting for variability in survey conditions (e.g. acoustic noise, and wind, cloud and sea state) across land-based and subsurface analyses was also highlighted. The methodological toolbox developed and successfully applied in this study, comprising high-resolution visual and acoustic data, and a variety of environmental parameters, provides a relatively low-cost and effective method for determining fine-scale habitat use of mobile top predators in dynamic, topographically-complex nearshore environments, where vessel-based surveys may be impractical.
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Wagenbrenner, Joseph William. "Post-fire stream channel processes| Changes in runoff rates, sediment delivery across spatial scales, and mitigation effectiveness." Thesis, Washington State University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3598132.
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<p> Wildfires dramatically affect hydrologic processes including runoff and erosion, which in turn can impact society. Disturbance by fire creates ecosystem heterogeneity, prompting many species to adapt to fire cycles. Human impacts have altered fire frequency and affected natural systems to the point that additional landscape-scale disturbances may cause a disruption in ecosystem form and function. The altered ecosystems and increased development in forests may exacerbate post-fire impacts, affecting more of the population in fire-prone regions. </p><p> The following three studies will improve our understanding and management of post-fire impacts on stream channel processes. A catchment in eastern Arizona where runoff data were collected between 1962 and 1983 was subsequently burned by a wildfire in 2011. The direct comparison of pre and post-fire runoff showed that the fire made runoff more rapid, increased peak discharge rates, and compressed the time scale of storm hydrographs. These results can help improve post-fire runoff modeling and management efforts. </p><p> The second topic addressed the scaling of sediment delivery across hillslope and small catchment scales. Erosion data used in this study were from the Arizona site and five other sites across the western US. Results from five of the six sites showed that sediment delivery significantly decreased with increasing spatial extent, while the lack of trend at the sixth site illustrates the variability in erosion responses across ecosystems. The relationships developed in this study will help improve estimates of sediment delivery rates at the small-catchment scale using more easily acquired data from small plots. </p><p> The third study addressed whether straw bale check dams reduce post-fire sediment yields or affect ephemeral stream channel morphology. A series of laboratory flume experiments based on measured post-fire field conditions showed that check dams can store sediment from initial runoff events, but that a large number of check dams would be needed to reduce post-fire sediment yields. The stored sediment reduced the local channel gradient, but the check dams did not otherwise affect the channel morphology. These data and field observations were used to develop a check dam classification system that can be applied in ephemeral streams in burned or unburned areas.</p>
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Rai, kurlethimar Yashas. "Visual attention for quality prediction at fine spatio-temporal scales : from perceptual weighting towards visual disruption modeling." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4027/document.
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Cette thèse revisite les relations entre les processus attentionnels visuels et la perception de qualité. Nous nous intéressons à la perception de dégradation dans des séquences d’images et leur impact sur la perception de qualité. Plutôt qu’un approcha globale, nous travaillons à une échelle spatio temporelle fine, plus adaptée aux décisions des encodeurs vidéo. Deux approches liant attention visuelle et qualité perçue sont explorées. La première, suit une approche classique, de type pondération des distorsions. Ceci est mis en relation avec des scénarios d’usage comme le streaming interactif ou la visualisation de contenus omnidirectionnels. Une seconde approche nous amène à introduire le concept de disruption visuelle (DV) et sa relation avec la perception de qualité. Nous proposons d’abord des techniques permettant d’étudier les saccades résultantes de la DV à partir par de données expérimentales oculométriques. Nous proposons ensuite un modèle computationnel de prédiction de la DV. Une nouvelle mesure objective de qualité est ainsi introduite nommée "Disruption Metric" permettant l’évaluation de la qualité locale de vidéos. Les résultats obtenus trouvent leurs applications dans de nombreux domaines tels que l’évaluation de qualité, la compression, la transmission perpétuellement optimisée de contenus visuel ou le rendu/visualisation foéval<br>This thesis revisits the relationship between visual attentional processes and the perception of quality. We mainly focus on the perception of degradation in video sequences and their overall impact on our perception of quality. Rather than a global approach, we work in a very localized spatio-temporal scale, more adapted to the decision-process in video encoders. Two approaches linking visual attention and perceived quality are explored in the thesis. The first follows a classical approach, of the distortion weighting type. This is very useful in certain scenarios such as interactive streaming or visualization of omni-directional content. The second approach leads us to the introduction of the concept of visual disruption(DV), and explore its relation to perceived quality. We first propose techniques for studying the saccades related to DV from experimental oculometric data. Then, a computational model for the prediction of DV is proposed. A new objective measurement of quality is therefore born, which we call the "Disruption Metric" : that allows the evaluation of the local quality of videos. The results obtained, find their applications in many fields such as quality evaluation, compression, perpetually optimized transmission of visual content or foveated rendering / transmission
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Paull, David James Physical Environmental & Mathematical Sciences Australian Defence Force Academy UNSW. "Habitat fragmentation and the southern brown bandicoot Isoodon obesulus at multiple spatial scales." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Physical, Environmental and Mathematical Sciences, 2003. http://handle.unsw.edu.au/1959.4/38698.
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This thesis investigates the process of habitat fragmentation and the spatial and temporal scales at which it occurs. Fragmentation has become an important topic in biogeography and conservation biology because of the impacts it has upon species??? distributions and biodiversity. Various definitions of fragmentation are available but in this research it is considered to be the disruption of continuity, either natural or human-induced in its origins and operative at multiple spatial scales. Using the distribution of the southern brown bandicoot Isoodon obesulus as a case study, three spatial scales of fragmentation were analysed. At the continental scale, the Australian distribution of the subspecies I. o. obesulus was examined in relation to climate, geology and vegetation cover at the time of European settlement of Australia and two centuries later. Using archived wildlife records and Geographic Information Systems (GIS) analyses, habitat suitability models were created to assess natural and human-induced fragmentation of the distribution of I. obesulus in 1788 and 1988. At the regional scale, a study was made of the distribution of I. obesulus in the south-east of the State of South Australia. Again, natural and human-induced patterns of habitat fragmentation were modelled using GIS with climate, soil and vegetation data for the time of European settlement and at present. At the local scale, the distribution of I. obesulus was the subject of a detailed field survey of 372 sites within 29 remnant patches of native vegetation in south-eastern South Australia in order to understand the variables that cause habitat fragmentation. Geographic information systems were used again but in a different way to carefully stratify the field survey by overlaying maps of topography, vegetation and past fires. The large dataset collected from the surveys was described using six generalized linear models which identified the significant variables that fragment the distribution of I. obesulus at a local scale. From the results of the field surveys, a subset of four remnants was chosen for further GIS spatial modelling of the probability of I. obesulus occurring within remnants in response to fire via a controlled burning programme put in place to reduce accumulating fuel loads. These investigations show that habitat fragmentation can be caused by different factors at different spatial scales. At the continental scale, it was found that climate played a dominant role in influencing the fragmented distribution of I. obesulus but vegetation change during the past two centuries has also had a profound impact on the availability of habitat. Within south-eastern South Australia, the species??? regional scale distribution is constrained by climate and also by soil and vegetation patterns. Dramatic change to its regional distribution occurred in the 20th century as a result of the clearance of native vegetation for planting pastures, crops and pines. Fragmentation at the regional scale has resulted in the remaining habitat being reduced to small, isolated, remnant patches of native vegetation. At the local scale it was found that variables which disrupt the continuity of I. obesulus habitat within remnants include vegetation cover in the 0-1 m stratum, abundance of Xanthorrhoea australis and soil texture. For a subset of sites located in one landsystem of the study area, named Young, the age of vegetation since it was last burnt was also found to be a significant variable, with vegetation 10-14 years old since burning providing the most suitable habitat. Spatial modelling of two scenarios for prescribed burning over 15 years revealed that the use of fire as a habitat enhancement tool will be complicated and require a detailed understanding of the factors that cause natural fragmentation in the distribution of I. obesulus at the local scale. A further conclusion of the study was that ecological relationships between species and their habitats require careful interpretation of multi-scaled datasets and conservation plans for endangered species ought to be made at multiple spatial scales. Future research directions are identified including the linking of multi-scaled habitat fragmentation models to genetic studies of the species throughout its range.
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Robin, Vincent. "Reconstruction of fire and forest history on several investigation sites in Germany, based on long and short-term investigations - Multiproxy approaches contributing to naturalness assessment on a local scale." Thesis, Aix-Marseille 3, 2011. http://www.theses.fr/2011AIX30057.
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Sur la base de constats globaux concernant l’importance d’appliquer des modes de gestion durable des zones forestières et le manque d’investigation concernant l’histoire passée des feux en Europe centrale, il a été entrepris de reconstruire l’histoire des événements de feux et de la dynamique forestière pour des sites d’étude en Allemagne. L’ensemble des données obtenues et analysées ont été utilisées pour l’évaluation du niveau de naturalité des sites étudiés, cette notion étant essentielle pour la mise en place d’une gestion durable, et/ou pour des projets de conservation et / ou de restauration des systèmes perturbés. Concernant les dynamiques des écosystèmes en Europe centrale, il a été souvent mis en évidence que l’homme joue un rôle essentiel depuis des millénaires. Par conséquent, l’approche historique des événements de feux et de la dynamique forestière à été réalisée sur de longues échelles temporelles. Neuf sites d’étude ont été sélectionnés incluant une large gamme de systèmes forestiers d’Europe centrale. Les sites d’études sont répartis dans deux zones générales d’étude : le nord de l’Allemagne (Schleswig-Holstein), qui comprend quatre sites d’étude, et le centre de l’Allemagne (le Harz), qui comprend cinq sites d’étude. Quatre disciplines ont été principalement utilisées. Pour définir l’état actuel des sites d’études ceux-ci ont été caractérisés, utilisant divers indicateurs dendrométriques concernant la structure et la composition des parcelles analysées. Pour obtenir des informations à propos de la dynamique forestière des peuplements forestiers en place des analyses dendroécologiques ont été utilisées. Pour analyser la dynamique forestière sur une longue échelle temporelle, à une échelle spatiale comparable, des analyses pédoanthracologiques ont été menées, combinées à des analyses de sols. De plus, des analyses anthracologiques de séquences de tourbes ont été réalisées, fournissant, combinées avec les données pedoanthracologiques, des enseignements à propos de l’histoire des incendies. L’état actuel et la dynamique forestière récente des sites étudiés indiquent divers niveaux de complexité des peuplements forestiers, correspondant souvent à divers niveaux postulés d’impact anthropique. Il a été obtenu huit chronologies moyennes, standardisées en haute et moyenne fréquences, âgées au maximum de 1744 et au minimum de 1923 ans. A partir de ces chronologies des changements dans les conditions de croissance de peuplements forestiers ont été mises en évidence. Basées sur un ensemble de 71 charbons de bois datés par radiocarbone, il a été mis en évidence, à l’échelle locale et globale, deux principales phases présentant plus d’événements de feux datés, une durant le Pléistocène supérieur/Holocène inférieur, une autre durant l’Holocène supérieur. Pour les deux phases identifiées des forçages climatique et anthropogénique ont été respectivement postulés comme déterminisme des occurrences de feux. Finalement, les différentes données collectées ont été utilisées de façon combinée pour reconstruire l’histoire des feux et des forêts des sites étudiés, afin de contribuer à l’évaluation de leur niveau de naturalité<br>Considering two global observations in Central Europe of, firstly, the need for, and development of, sustainable and biological conservation practices for forest and/or woodland areas and, secondly, the lack of long-term fire history, an attempt has been made to reconstruct the fire and the forest history at several investigation sites in Germany. The overall data set gathered and analyzed has been used for on-site naturalness assessment. This latter notion is crucial for forest system conservation/restoration planning, considering the past human impact on forest dynamics. Also, in view of this past human impact on forest systems, which is well-documented for Central Europe, as occurring on a multi-millennium scale, an historical perspective perceptive that combined a long and short temporal scale of investigation was used.Nine investigation sites were selected, in order to include various and representative types of Central European forest. Therefore, the investigation sites were located in two main investigation areas. One is in Northern Germany (Schleswig-Holstein) and includes four investigation sites. The other is in Central Germany (Harz Mountains) and includes five investigation sites. Four main approaches were used. To assess the current state of the investigated site, forest stand characterization was undertaken (i.e. based on various forest attributes that concern stand structure and composition). Tree ring series were analyzed to provide insights about short-term forest tree population dynamics. Then, charcoal records from soil (combined with soil analysis) and peat sequences were qualitatively and quantitatively analyzed. These last two approaches also provide information about the past fire history. Forest current and short-term dynamics illustrated various levels of stand complexity, often corresponding to various levels of human impact that had been postulated. Eight mean site tree-ring chronologies, standardized in high and mid-frequency signal, spanning at a maximum of up to AD 1744 and at a minimum of up to AD 1923, were obtained. The insight, about the identification of events of growing changes and the correlated temporal and, if possible, spatial patterns, was discussed. Charcoal analysis provided a long-term insight about fire history. Based on 71 charcoal radiocarbon dates, it was shown on a macro-scale that there were two phases that had a greater frequency of fire - one during the transition from the late Pleistocene to the early Holocene, and one during the mid- and late Holocene. A strong human control during the most recent fire phase has been postulated. This is supported by on-site soil and peat charcoal record analysis, allowing one to point out the event of environmental changes (disturbances), at local scales. In the end, the on-site data from the various indicators were combined to assess the fire and forest history and the naturalness level of the investigated sites, based on past insights, thereby contributing to a better understanding of the present and helping to anticipate the future
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Desbiolles, Fabien. "Impact des fines échelles spatio-temporelles de l'atmosphère sur le couplage entre océan hauturier et plateau continental dans un système d'upwelling de bord Est." Thesis, Brest, 2014. http://www.theses.fr/2014BRES0121/document.
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Cette thèse s'intéresse à la dynamique océanique induite par les échelles spatiales et temporelles de l'atmosphère, et du vent en particulier, dans les régions d'upwelling du Benguela et des Canaries. Ces régions sont sous l'influence d'un vent local ou régional, soufflant parallèlement à la côte. "Moteur" principal de la résurgence d'eau froide, ce vent est modulé par des processus physiques à des échelles spatio-temporelles variées. La nature des interactions avec l'atmosphère, l'océan et le continent environnants diffère selon les processus. Depuis deux décennies, des efforts remarquables portent sur la description par télédétection des champs atmosphériques à la surface de l’océan. Un nombre croissant de missions spatiales et des améliorations techniques majeures ont permis de raffiner la résolution horizontale et temporelle des produits disponibles à l'échelle globale. La disponibilité de multiples mesures diffusiométriques grillées, traitées et distribuées par le LOSCERSAT,nous amène dans un premier temps à comparer et analyser la richesse et la finesse des échelles retranscrites par différents produits. Ainsi, plusieurs gammes d'échelles de vent sont différenciées et leurs signatures sur l'upwelling côtier sont étudiées. L'intensité des anticyclones subtropicaux (Sainte Hélène et Açores) module la saisonnalité de l'upwelling le long des côtes Ouest africaines. Les régions centrales des upwellings de l’Atlantique, sous l'influence permanente de ces centres de haute pression, sont ainsi les cellules d'upwelling les plus intenses de chacun des systèmes en termes de pérennité et d'intensité (cellule de Lüderitz et cellule de Dakhla respectivement dans l'hémisphère Sud et l'hémisphère Nord). À l'échelle régionale, ou l'échelle des sous-bassins (O(1000 km)), la variabilité intrasaisonnière du vent est contrôlée par le renforcement ou l'atténuation des anticyclones entraînant à la côte l'activation ou la relaxation d'événements d'upwelling. À des échelles plus petites (O(100 km)), le front caractéristique de température de surface (SST) entre la côte et le large façonne la structure spatiale du vent par des processus de stabilisation/déstabilisation de la colonne d'air. Un vent soufflant en direction de l'équateur et parallèlement à un front de SST aura tendance à diminuer (augmenter) sur le flanc froid (chaud) de ce front. Le rotationnel (la divergence) du vent est directement impacté(e) et répond linéairement, au premier ordre, à la composante du gradient de SST normale (tangentielle) à la direction du vent. Ces rétroactions océaniques sont caractérisées par une échelle temporelle allant de l'hebdomadaire au mensuel. Enfin, de fines échelles du vent sont couramment observées dans les premiers kilomètres de l’océan au voisinage de la côte. L’interface entre le large et le continent est en effet associée à un affaiblissement significatif des vents. L'extension zonale de cette transition (O(10 km)) dépend notamment de l'orographie et de la rugosité de surface du continent adjacent. L'impact d'une telle réduction du vent sur la structure des upwellings côtiers, la dynamique sous-jacente et le transport côte-large de particules est appréhendé à l'aide d'analyses numériques eulériennes et lagrangiennes<br>This study focuses on the oceanic response to fine atmospheric spatial and temporal scales, and especially fine wind patterns in the Benguela and Canary upwelling systems. These regions are under the influence of local or regional wind, blowing parallel to the coast. Thewind is the main driver of the cold-water upwelling and is modulated by several physical processes at various scales. The nature of the interactions with the atmosphere, the ocean and the adjacent continent differs according to these processes. For the past 20 years, outstanding efforts have been made in the description and understanding of the atmospheric conditions at the sea surface. An increasing number of space missions and major technical improvements have allowed refinement of the horizontaland temporal resolution of the products available at global scale. The availability of multiple gridded scatterometer measurements,processed and distributed by the LOS-CERSAT, brings us first to compare and analyze the richness and fineness of the scales of a few products. We differentiate several wind scales and study their signatures on coastal upwelling dynamics. The intensity of the subtropical anticyclones (Saint Helena andAzores) modulates the seasonality of the upwelling along the Africanwest coast. The central regions of both upwelling systems are permanently under the influence of these atmospheric highs and,thus, are the most intense upwelling cells of each system, both interms of durability and intensity (Lüderitz and Dakhla cells for the southern and the northern hemisphere, respectively). On a regional scale, or basin scale (O(1000 km)), the intraseasonal wind variability is driven by the strengthening or weakening of these anticyclones, causing the activation or relaxation of upwelling events at the coast.At smaller scales (O(100 km)), the characteristic sea surface temperature (SST) front between the coastal and open ocean shapes the spatial structure of the wind by stabilization/destabilization of the air column. An equatorward-blowing wind parallel to an SST front tends to decrease (increase) on the cold side (warm) of this front. The curl (divergence) of the wind is directly impacted and the first order response varies linearly with the crosswind (downwind) SST gradient. This oceanic feedback is characterized by weekly to monthly temporal scales. Finally, small-scale wind structures are frequently observed in the first kilometers of the coastal ocean. Indeed, the interface between the open ocean and the continent is associated with a significant wind drop-off. The zonal extension of this transition (O(10 km) depends on the orography and on the surface roughness of the adjacent continent. The impact of such a wind reduction on the structure of the coastal upwelling, the underlying ocean dynamics and the cross-shore transport of particles is diagnosed with both Eulerian and Lagrangian numerical analyses
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Hulet, April. "An Object-Based Image Analysis of Treated and Untreated Pinyon and Juniper Woodlands Across the Great Basin." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3406.
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Land managers need to rapidly assess vegetation composition and bare ground to effectively evaluate, manage, and restore shrub steppe communities that have been encroached by pinyon and juniper (P-J) trees. A major part of this process is assessing where to apply mechanical and prescribed fire treatments to reduce fuel loads and maintain or restore sagebrush steppe rangelands. Geospatial technologies, particularly remote sensing, offers an efficient option to assess rangelands across multiple spatial scales while reducing the need for ground-based sampling measurements. High-spatial resolution color-infrared imagery (0.06-m pixels) was acquired for sagebrush steppe communities invaded by P-J trees at five sites in Oregon, California, Nevada, and Utah with a Vexcel Ultra CamX digital camera in June/July 2009. In addition to untreated P-J woodlands, imagery was acquired over P-J woodlands where fuels were reduced by either prescribed fire, tree cutting, or mastication treatments. Ground measurements were simultaneously collected at each site in 2009 on 0.1-hectare subplots as part of the Sagebrush Steppe Treatment Evaluation Project (SageSTEP). We used Trimble eCognition Developer to 1) develop efficient methods to estimate land cover classes found in P-J woodlands; 2) determine the relationship between ground measurements and object-based image analysis (OBIA) land cover measurements for the following classes: trees (live, burned, cut, and masticated), shrubs, perennial herbaceous vegetation, litter (including annual species), and bare ground; and 3) evaluate eCognition rule-sets (models) across four spatial scales (subplot, site, region, and network) using untreated P-J woodland imagery. At the site scale, the overall accuracy of our thematic maps for untreated P-J woodlands was 84% with a kappa statistic of 0.80. For treatments, the overall accuracy and kappa statistic for prescribed fire was 85% and 0.81; cut and fell 82% and 0.77, and mastication 84% and 0.80, respectively, each indicating strong agreement between OBIA classification and ground measured data. Differences between mean cover estimates using OBIA and ground-measurements were not consistently higher or lower for any land cover class and when evaluated for individual sites, were within 5% of each other; all regional and network OBIA mean cover estimates were within 10% of the ground measurements. The trade-off for decreased precision over a larger area (region and network scale) may be useful to prioritize fuel-management strategies but will unlikely capture subtle shifts in understory plant communities that site and subplot spatial scales often capture. Although cover assessments from OBIA differed somewhat from ground measurements, they were accurate enough for many landscape-assessment applications such as evaluating treatment success and assessing the spatial distribution of fuels following fuel-reduction treatments on a site scale.
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Catano, Christopher. "Species and habitat interactions of the gopher tortoise: A keystone species?" Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5153.
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Species-species and species-habitat interactions have been demonstrated to be important in influencing diversity across a variety of ecosystems. Despite generalities in the importance of these interactions, appropriate mechanisms to explain them are absent in many systems. In sandhill systems of the southeast U.S., gopher tortoises have been hypothesized to be a crucial species in the maintenance of diversity and function. However, the mechanisms and magnitude in which they influence their communities and habitats have rarely been empirically quantified. I examined how habitat structure influences tortoise abandonment of burrows and how tortoise densities influence non-volant vertebrate community diversity. Tortoise burrow abandonment is directly influenced by canopy closure, with each percent increase in canopy cover relating to a ~2% increase in the probability of burrow abandonment. In addition, tortoise burrow density was positively correlated with diversity and evenness, but not species richness. This influence was directly proportional to burrow density, supporting a dominance role for this species and rejecting the commonly asserted keystone species mechanism. I also quantified the influence of tortoises in influencing diversity relative to other environmental and habitat variables. Through this research, I have demonstrated that disturbance and habitat structure are important, but diversity responds most to density of burrows in the habitat. These findings demonstrate the intricate relationships interacting to maintaining diversity in sandhill systems. In particular, habitat change leading to declines of gopher tortoises may have drastic negative impacts on vertebrate species diversity.<br>M.S.<br>Masters<br>Biology<br>Sciences<br>Biology
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King, Stephanie. "Fine-scale temporal and spatial variability in the coastal waters of Clayoquot Sound." Thesis, 2010. http://hdl.handle.net/1828/3043.
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An oceanographic buoy with 10 atmospheric and oceanographic instruments was
deployed in Clayoquot Sound on the west coast of Canada in 2007. The high-resolution
time series was used to monitor the fine-scale variability in the coastal ocean. Over 700 CTD profiles measuring temperature, salinity and chlorophyll fluorescence made in the region of the buoy were used to relate the buoy data to spatial patterns. Analysis showed that large-scale upwelling in combination with the localized winds and tidal currents affect water properties at time scales of hours to days. At low tide the buoy represented inland water and at high tide the buoy represented offshore water. Both the buoy data and CTD profiles measured a strong offshore/onshore gradient. For temperature the gradient depended on the direction of the wind, salinity was always higher offshore compared to onshore, and the chlorophyll fluorescence was higher onshore in the early spring and higher offshore for the rest of the time series. The fine scale temporal resolution of the buoy was able to capture the variability measured by the CTD profiles in a 40km2 area. This work shows the importance of making high-resolution temporal measurements in the coastal ocean. However, these types of moorings also require
frequent maintenance. In Clayoquot Sound, the optical sensors needed to be cleaned
every 4-6 days.
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Frazer, Gordon Wilson. "Fine-scale, multidimensional spatial patterns of forest canopy structure derived from remotely sensed and simulated datasets." Thesis, 2007. http://hdl.handle.net/1828/2496.
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Forests are not simply storehouses of timber or wood fibre for human consumption and economic development. They represent structurally and ecologically rich habitat for an estimated 40 percent of the earth's extant species, and form the functional interface between the biosphere and atmosphere for some 27 percent of the earth's terrestrial surface. Forests, therefore, play a vital role in the maintenance of biodiversity and the regulation of local to global scale ecosystem processes and functions. Present strategies for conserving biodiversity in managed forests are based on the notion that maintaining the full range of structural conditions historically present in natural forests is the best approach for assuring the long-term persistence of a broad range of native species. The overarching goal of this dissertation is to contribute to the development of novel forest measurements that are relevant to organisms and ecosystems, and much needed by forest scientists and managers to recognize and retain the key elements and patterns of forest structure that are crucial for the conservation of forest biodiversity. This study focuses explicitly on fine-spatial-scale, multidimensional patterns of forest canopy structure based on the assumption that the 'canopy' is the primary focal site of complex interactions between vegetation and the physical enviromnent. Two disparate remote sensing technologies-ground-based hemispherical (fisheye) canopy photography and airborne discrete-return LiDAR-are employed to characterize angular, vertical, and horizontal patterns of forest canopy structure. A quantitative technique is developed for precise measurements of gap fraction (P), element clumping (O), mean projection coefficient (G), and leaf area index (L) from sequences (sets) of black and white pixels extracted at specific view angles in digital fisheye photos. Results are compared with three other leading techniques and validated using well-documented simulated and real fisheye photosets. Variables P, O, G, and L control light capture and penetration in forest canopies, and are key input parameters for process-based models of stand productivity, stand dynamics, and material (CO2 and H20) and energy fluxes between the canopy and atmosphere. Findings show that this new technique consistently produced the best estimates of stand LAI in each of the three experimental forest sites. However, further validation work is required to determine the adequacy of these methods in other closed and discontinuous canopies. Finally, a methodological framework is devised for quantifying, classifying, and comparing fine-spatial-scale vertical and horizontal patterns of canopy structure derived from airborne LiDAR data. This methodology is tested with simulated forest canopies and ultimately demonstrated using an airborne LiDAR dataset collected over very young to old, coastal Douglas-fir/western hemlock forests on Vancouver Island, British Columbia. A pseudo 'space-for-time substitution' sampling approach is used to investigate age-related developmental changes in canopy structure at decadal and century time scales. Discrete classes of vertical and horizontal canopy structure are identified by k-means partitioning. The structural differences found among age-classes were consistent with the characteristics, patterns, and dynamics predicted by generalized models of stand development for similar coastal Douglas-fir/western hemlock forests of northwestern North America.
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Chattopadhyay, Bodhisattwa. "Fine-Scale Structure Of The Diurnal Cycle Of Global Tropical Rainfall." Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2591.
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The fine-scale structure of global (30N-30S) tropical rainfall is characterised using 13 years (1998-2010) of 3-hourly and daily, 0.25-degree Tropical Rainfall Measuring Mission (TRMM) 3B42 rainfall product. At the outset, the dominant timescales present in rainfall are identified. Specifically, the Fourier spectrum (in time) is estimated in two ways (a) spectrum of spatially averaged (SoSA) rainfall; and (b) spatial average of the spectrum (SAoS) of rainfall at each grid point. This procedure is applied on rainfall at the 3-hourly and daily temporal resolutions. Both estimates of the spectrum show the presence of a very strong seasonal cycle. But, at subseasonal timescales, the two methods of estimating spectrum show a marked difference in daily rainfall. Specifically, with SoSA the variability peaks at a subseasonal timescale of around 5 days, with a possible secondary peak around 30-40 days (mostly in the southern tropics). With SAoS, the variability is distributed across a range of timescales, from 2 days to 90 days. However, with finer resolution (3-hourly) observations, it is seen that (besides the seasonal cycle) both methods agree and yield a dominant diurnal scale.
Along with other subseasonal scales, the contribution and geographical distribution of diurnal scale variability is estimated and shown to be highly significant. Given its large contribution to the variability of tropical rainfall, the diurnal cycle is extracted by means of a Fourier-based filtering and analysed. The diurnal rainfall anomaly is constructed by eliminating all timescales larger than 1 day. Following this, taking care to avoid spurious peaks associated with Gibbs oscillations, the time of day (called the peak octet) when the diurnal anomaly is largest is identified. The peak octet is estimated for each location in the global tropics. This is repeated for 13 years, and the resulting mode of the time of maximum rainfall is established. It is seen that (i) most land regions receive rainfall during the late afternoon/early evening hours; (ii) rainfall over open oceans lack a dominant diurnal signature with a possible combination of early morning and afternoon showers; (iii) coastal regions show a clear south/southwest propagation in the mode of the peak octet of rainfall. In addition to being a comprehensive documentation of the diurnal cycle at very fine scales, the results serve as a critical test for the validation of theoretical and numerical models of global tropical rainfall.
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LaBrecque, Erin. "Spatial Relationships among Hydroacoustic, Hydrographic and Top Predator Patterns: Cetacean Distributions in the Mid-Atlantic Bight." Diss., 2016. http://hdl.handle.net/10161/12277.
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<p>Effective conservation and management of top predators requires a comprehensive understanding of their distributions and of the underlying biological and physical processes that affect these distributions. The Mid-Atlantic Bight shelf break system is a dynamic and productive region where at least 32 species of cetaceans have been recorded through various systematic and opportunistic marine mammal surveys from the 1970s through 2012. My dissertation characterizes the spatial distribution and habitat of cetaceans in the Mid-Atlantic Bight shelf break system by utilizing marine mammal line-transect survey data, synoptic multi-frequency active acoustic data, and fine-scale hydrographic data collected during the 2011 summer Atlantic Marine Assessment Program for Protected Species (AMAPPS) survey. Although studies describing cetacean habitat and distributions have been previously conducted in the Mid-Atlantic Bight, my research specifically focuses on the shelf break region to elucidate both the physical and biological processes that influence cetacean distribution patterns within this cetacean hotspot. </p><p>In Chapter One I review biologically important areas for cetaceans in the Atlantic waters of the United States. I describe the study area, the shelf break region of the Mid-Atlantic Bight, in terms of the general oceanography, productivity and biodiversity. According to recent habitat-based cetacean density models, the shelf break region is an area of high cetacean abundance and density, yet little research is directed at understanding the mechanisms that establish this region as a cetacean hotspot. </p><p>In Chapter Two I present the basic physical principles of sound in water and describe the methodology used to categorize opportunistically collected multi-frequency active acoustic data using frequency responses techniques. Frequency response classification methods are usually employed in conjunction with net-tow data, but the logistics of the 2011 AMAPPS survey did not allow for appropriate net-tow data to be collected. Biologically meaningful information can be extracted from acoustic scattering regions by comparing the frequency response curves of acoustic regions to theoretical curves of known scattering models. Using the five frequencies on the EK60 system (18, 38, 70, 120, and 200 kHz), three categories of scatterers were defined: fish-like (with swim bladder), nekton-like (e.g., euphausiids), and plankton-like (e.g., copepods). I also employed a multi-frequency acoustic categorization method using three frequencies (18, 38, and 120 kHz) that has been used in the Gulf of Maine and Georges Bank which is based the presence or absence of volume backscatter above a threshold. This method is more objective than the comparison of frequency response curves because it uses an established backscatter value for the threshold. By removing all data below the threshold, only strong scattering information is retained.</p><p>In Chapter Three I analyze the distribution of the categorized acoustic regions of interest during the daytime cross shelf transects. Over all transects, plankton-like acoustic regions of interest were detected most frequently, followed by fish-like acoustic regions and then nekton-like acoustic regions. Plankton-like detections were the only significantly different acoustic detections per kilometer, although nekton-like detections were only slightly not significant. Using the threshold categorization method by Jech and Michaels (2006) provides a more conservative and discrete detection of acoustic scatterers and allows me to retrieve backscatter values along transects in areas that have been categorized. This provides continuous data values that can be integrated at discrete spatial increments for wavelet analysis. Wavelet analysis indicates significant spatial scales of interest for fish-like and nekton-like acoustic backscatter range from one to four kilometers and vary among transects. </p><p>In Chapter Four I analyze the fine scale distribution of cetaceans in the shelf break system of the Mid-Atlantic Bight using corrected sightings per trackline region, classification trees, multidimensional scaling, and random forest analysis. I describe habitat for common dolphins, Risso’s dolphins and sperm whales. From the distribution of cetacean sightings, patterns of habitat start to emerge: within the shelf break region of the Mid-Atlantic Bight, common dolphins were sighted more prevalently over the shelf while sperm whales were more frequently found in the deep waters offshore and Risso’s dolphins were most prevalent at the shelf break. Multidimensional scaling presents clear environmental separation among common dolphins and Risso’s dolphins and sperm whales. The sperm whale random forest habitat model had the lowest misclassification error (0.30) and the Risso’s dolphin random forest habitat model had the greatest misclassification error (0.37). Shallow water depth (less than 148 meters) was the primary variable selected in the classification model for common dolphin habitat. Distance to surface density fronts and surface temperature fronts were the primary variables selected in the classification models to describe Risso’s dolphin habitat and sperm whale habitat respectively. When mapped back into geographic space, these three cetacean species occupy different fine-scale habitats within the dynamic Mid-Atlantic Bight shelf break system. </p><p>In Chapter Five I present a summary of the previous chapters and present potential analytical steps to address ecological questions pertaining the dynamic shelf break region. Taken together, the results of my dissertation demonstrate the use of opportunistically collected data in ecosystem studies; emphasize the need to incorporate middle trophic level data and oceanographic features into cetacean habitat models; and emphasize the importance of developing more mechanistic understanding of dynamic ecosystems.</p><br>Dissertation
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Warman, Leanna Dawn. "Identifying priority conservation areas using systematic reserve selection and GIS at a fine spatial scale : a test case using threatened vertebrate species in the Okanagan, British Columbia." Thesis, 2002. http://hdl.handle.net/2429/12317.
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Biologists and wildlife managers recognise the need for systematic reserve selection
techniques to conserve habitat for species. Geographic information systems (GIS) provide a
tool that helps identify conservation areas using geographically referenced data. Mapping
continuous geographical phenomena with discreet boundaries affects the spatial organisation
of data. However, most published studies of systematic reserve selection techniques have
been completed at only one level of data organisation and usually for large regions at coarse
scales. In this thesis, I examined the effects of data organisation on reserve selection in the
South Okanagan, a small region in British Columbia. I used the software program "C-Plan"
with ArcView GIS to identify the minimum amount of area required to achieve explicit
conservation targets that maintain species within the region. I evaluated the reserve selection
technique using terrestrial ecosystem mapping (TEM) and species habitat models that predict
the suitability of T EM polygons for each of twenty-nine threatened vertebrate species. C-Plan
selected 37.2% of the region to represent habitat that maintains current population sizes of
these threatened vertebrate species. Although habitat area targets were achieved, these
priority sites were small and scattered throughout the region and were therefore not practical
for implementation or viable for many species. I examined the effects of data organisation on
priority site selection by altering three algorithm parameters: (1) size and shape of the unit
used to map data and select sites, (2) type of species included in selections, and (3) quantity of
the conservation target for each species. The spatial overlap of priority sets of sites that were
identified for different values of each parameter was low. Therefore, the spatial distribution
of priority conservation sites depends on values for these parameters. Data organisation also
influenced the evaluation of existing protected areas in the region for maintaining the
threatened vertebrate species. Both selection unit size and assignment of protection status to
selection units, based on area of overlap with actual protected areas, resulted in different
evaluations of reserve performance. I demonstrate that systematic reserve selection cannot be
performed with data at only one spatial organisation unless the consequences are recognised.
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Yang, Hsueh-Chan, and 楊學展. "Spatial Configuration and Sign systems and Their Combined Influence on Way-finding Behavior in Large Scale Exhibition Spaces- A case study on National Taiwan Museum of Fine Arts." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/96190888673966321973.
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碩士<br>逢甲大學<br>建築所<br>95<br>The foundations of the Museum are education, research, exhibition, and collection. And how to improve the service quality of museum by considering both of the sign system and spatial axial line is the important issue for this research. Therefore the mistake of the sign systems, site plan, and the spatial axial line in the construction of National Taiwan Museum of Fine Arts may causes way-finding behavior of visitors. Because of the administrators may ignore the sign systems, so that the complexity of circulation in exhibition space may cause way finding behavior of visitors.
We focus our study on museums by the methodology of Space Syntax analysis, developed by Bill Hillier, for our investigation and analysis in trying to understand the inherent organizing logic of the complex museum''s spatial and structural configuration. And we also use the Depthmap analysis to make a visibility graph representing the visible connections between those point locations, so that we can use the graph for spatial description and movement forecasting.
This research achievement have shown that the spatial configuration of high junctions of axis and high visibility may cause high frequency of way finding behavior of visitors .And if the junctions of axis exhibit more than four
interconnections, visitors easily get lost. Therefore, in order to reduce the frequency of way finding behavior, the suggestion is that the sign systems design of museum should be set at the junctions of the primary and secondary axis and at the high visibility places.
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STRAKOVÁ, Jitka. "Applicability of the EURURALIS Scenarios at the Fine Spatial Scales." Master's thesis, 2009. http://www.nusl.cz/ntk/nusl-85485.
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Růžičková, Anna. "Studium druhové bohatosti a složení společenstev mechorostů na velmi malé prostorové škále v souvislosti s in situ měřeným mikroklimatem." Master's thesis, 2021. http://www.nusl.cz/ntk/nusl-445969.
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The life of bryophytes is closely connected with their surrounding environment. Changes in atmospheric conditions on the microscale directly affect the physiological functions of bryophytes, which in turn determine their distribution. The current development of technologies allows us to measure the microclimate affecting bryophytes directly in the field. Nevertheless, there have not been many studies published examining the response of bryophytes to in situ measured microclimate. This diploma thesis is one of the first in Europe to provide data from continuous field microclimatic measurement performed on a scale relevant to bryophytes. It deals with the influence of the microclimate on the bryophyte species richness and community composition within a single gorge in the Bohemian Switzerland National Park. For 17 months, 38 HOBO Pro v2 Onset dataloggers were recording air temperature and air humidity 10 cm above the ground. I performed detailed bryological survey on two differently sized plots (circle with a radius of 1 or 2 m) around each of the dataloggers. The microclimate is influenced by the topography and character of the vegetation, therefore I derived topographical data from a digital terrain model (resolution of 1 m), calculated the canopy openness using hemispherical photographs and...
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Faurés, Jean-Marc. "Sensitivity of runoff to small scale spatial variability of observed rainfall in a distributed model." 1990. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1990_669_sip1_w.pdf&type=application/pdf.
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Whitaker, Martha Patricia Lee. "Small-scale spatial variability of soil moisture and hydraulic conductivity in a semi-arid rangeland soil in Arizona." 1993. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1993_576_sip1_w.pdf&type=application/pdf.
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Wu, Yi-sui, and 吳宜穗. "A fine-scaled population spatial genetic structure analysis of Sassafras randaiense (Hay.) Rehder at Chi-lan Shan, Northeastern Taiwan." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/08473418890294964451.
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