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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Behavioral Responses of Willow Flycatchers, <i>Empidonax traillii</i>, to a Heterogeneous Environment

Bakian, Amanda V. 01 May 2011 (has links)
Spatial heterogeneity impacts population and community-level dynamics including species-level dispersal patterns, the use and availability of refugia, predator/prey dynamics, and reproductive fitness. Understanding how wild animal populations respond to environmental heterogeneity is essential for their proper management and conservation. In this study, I examine the responses of Willow Flycatchers to spatial heterogeneity in the distribution of their food and habitat resources. Over the course of three breeding seasons, I radio- tracked Willow Flycatchers at Fish Creek in Manti-La Sal National Forest in Utah, recorded detailed behavior data at each radio location, and collected fecal, feather and insect samples. I formulated individual and population-level Bayesian spatial resource selection functions to model Willow Flycatcher foraging and vocalization behavior on multiple scales. These models indicate that vocalization and foraging behavior are spatially segregated within the home ranges of Willow Flycatchers. Further, Willow Flycatchers were found to use mature riparian habitat for vocalizing while they used a variety of habitat types for foraging. The insect samples were used to identify distinct carbon and nitrogen stable isotope signatures for the aquatic and terrestrial insect communities at Fish Creek. In conjunction with the fecal samples, I used the stable isotope signatures to determine the contribution of aquatic versus terrestrial insects to the Willow Flycatcher diet. Aquatic insects comprised a larger proportion of the diet of adult than nestling Willow Flycatchers. This suggests that adult flycatchers consume a diet that is distinct from the one they feed to their nestlings. Finally, I compared space use characteristics in two populations of Willow Flycatchers: a population of the endangered Southwestern Willow Flycatcher at Roosevelt Lake, Arizona and another belonging to a non-endangered subspecies of Willow Flycatcher at Fish Creek, Utah. Differences in space use were found largely among breeding flycatchers while space use characteristics in non-breeding Willow Flycatchers did not differ across populations. This suggests that space use patterns in non-breeding Southwestern Willow Flycatchers may be generalizable to non-breeding flycatchers from non-endangered populations. This study expands our understanding of how Willow Flycatchers respond to spatial heterogeneity while its key findings have management and conservation implications for the species.
22

Urban types in rapidly urbanising cities

Lupala, John Modestus January 2002 (has links)
One of the challenges confronting cities innon-industrialised countries today is the fact that cities aregrowing at unprecedented rates, sizes and densities. Growthtrends in these cities are largely unregulated. In thesecountries, cities have changed in at least four major ways:their size, spatial organisation or morphology, the quality anddistribution of public services and infrastructure and theiremployment base. While this situation can be attributed toglobal urbanisation trends, the general poor knowledge on howthese cities develop, densify and acquire certain physicalcharacteristics has limited effective urban planning andmanagement. At times, the pervasive knowledge gap has beenassociated with the lack of relevant theories and concepts toexplain the evolution, growth and prevailing spatial qualities.However, the limited research in this field has alsocontributed to this problem. The other problem that confrontsthe rapidly urbanising city is continued sprawl that has beenmanifested in externalities of inadequate infrastructureprovision and under-utilisation of scarce resourcesparticularly land. This thesis is an attempt to contribute towards addressingthese two problem areas. The main field of study is on urbantypes within a rapidly urbanising city context. Dar es Salaamcity was selected a case study area. The study exploresthetheoretical framework for classification and analysis ofsettlements. The relevance of this framework in the studycontext is examined. At low scale level, the study provides ananalysis of house forms, density, plot characteristics, spacesand space uses in formal and informal settlements. The analysis shows that urbanisation under poverty andlow-density urban types greatly influence the sprawlingcharacter of the city. The increasing market-led housingdevelopment and ineffective planning responses are contributingfactors to the observed unguided densification anddeteriorating spatial qualities. It has also been shown thatwhile theoretical frameworks developed from most industrialisedcountries can be adapted to analyse urban types innon-industrialised countries, these theories are limited incomprehending fully the growth and character of rapidlyurbanising cities. <b>Key words:</b>Urban types, house forms, density, plotcharacteristics, spaces and space use, spatial quality, formaland informal settlements, Dar es Salaam.
23

Urban types in rapidly urbanising cities

Lupala, John Modestus January 2002 (has links)
<p>One of the challenges confronting cities innon-industrialised countries today is the fact that cities aregrowing at unprecedented rates, sizes and densities. Growthtrends in these cities are largely unregulated. In thesecountries, cities have changed in at least four major ways:their size, spatial organisation or morphology, the quality anddistribution of public services and infrastructure and theiremployment base. While this situation can be attributed toglobal urbanisation trends, the general poor knowledge on howthese cities develop, densify and acquire certain physicalcharacteristics has limited effective urban planning andmanagement. At times, the pervasive knowledge gap has beenassociated with the lack of relevant theories and concepts toexplain the evolution, growth and prevailing spatial qualities.However, the limited research in this field has alsocontributed to this problem. The other problem that confrontsthe rapidly urbanising city is continued sprawl that has beenmanifested in externalities of inadequate infrastructureprovision and under-utilisation of scarce resourcesparticularly land.</p><p>This thesis is an attempt to contribute towards addressingthese two problem areas. The main field of study is on urbantypes within a rapidly urbanising city context. Dar es Salaamcity was selected a case study area. The study exploresthetheoretical framework for classification and analysis ofsettlements. The relevance of this framework in the studycontext is examined. At low scale level, the study provides ananalysis of house forms, density, plot characteristics, spacesand space uses in formal and informal settlements.</p><p>The analysis shows that urbanisation under poverty andlow-density urban types greatly influence the sprawlingcharacter of the city. The increasing market-led housingdevelopment and ineffective planning responses are contributingfactors to the observed unguided densification anddeteriorating spatial qualities. It has also been shown thatwhile theoretical frameworks developed from most industrialisedcountries can be adapted to analyse urban types innon-industrialised countries, these theories are limited incomprehending fully the growth and character of rapidlyurbanising cities.</p><p><b>Key words:</b>Urban types, house forms, density, plotcharacteristics, spaces and space use, spatial quality, formaland informal settlements, Dar es Salaam.</p>
24

O espaço do carnaval na periferia da cidade de São Paulo / The Carnival Area in the suburb of São Paulo city

Nanci Frangiotti 21 August 2007 (has links)
No estudo apresentado, buscou-se compreender alguns aspectos que ocorrem no processo de urbanização da cidade de São Paulo. Há análise do uso do espaço e a sua apropriação, especialmente na periferia, tendo como mediação a produção do Carnaval e as relações sociais decorrentes. Abordam-se aspectos da formação urbana de São Paulo a partir da forte industrialização que se deu dos anos 50 e da extensa periferia que se formou na metrópole, especialmente dos anos 70 (séc. XX) em diante. Esse processo é analisado por meio da bibliografia e depoimentos colhidos, mantendo o viés Carnaval como mediação do direito ao encontro, à festa, à cidade. Analisa-se, ainda, a cooptação da festa pelo espetáculo-midiático e pelo poder público por meio do processo de alienação dos criadores da festa e dos resultados colhidos com o espetáculo. / Throughout the presented study, aspects of the urbanization process of São Paulo City are looked into. It analyses the space use and appropriation, especially in the City\'s suburban outskirts having as mediation, Carnival production and the social relations deriving from it. It goes into aspects of São Paulo\'s urban shaping by the strong industrialization period which took place during the 50s and the extensive suburban area growth on its outskirts beginning in the 70s. This process is analyzed by bibliography mean\'s and harvested depositions, keeping the bias Carnival as mediation of the right to the meeting, the party, the city. It also analyzes the co-option of the party towards the media-show and government format, through the alienation process of the party creators as well as the results coming from the show.
25

Modeling connectivity to identify current and future anthropogenic barriers to movement of large carnivores: A case study in the American Southwest

McClure, Meredith L., Dickson, Brett G., Nicholson, Kerry L. 06 1900 (has links)
This study sought to identify critical areas for puma (Puma concolor) movement across the state of Arizona in the American Southwest and to identify those most likely to be impacted by current and future human land uses, particularly expanding urban development and associated increases in traffic volume. Human populations in this region are expanding rapidly, with the potential for urban centers and busy roads to increasingly act as barriers to demographic and genetic connectivity of large-bodied, wide-ranging carnivores such as pumas, whose long-distance movements are likely to bring them into contact with human land uses and whose low tolerance both for and from humans may put them at risk unless opportunities for safe passage through or around human-modified landscapes are present. Brownian bridge movement models based on global positioning system collar data collected during bouts of active movement and linear mixed models were used to model habitat quality for puma movement; then, a wall-to-wall application of circuit theory models was used to produce a continuous statewide estimate of connectivity for puma movement and to identify pinch points, or bottlenecks, that may be most at risk of impacts from current and future traffic volume and expanding development. Rugged, shrub- and scrub-dominated regions were highlighted as those offering high quality movement habitat for pumas, and pinch points with the greatest potential impacts from expanding development and traffic, although widely distributed, were particularly prominent to the north and east of the city of Phoenix and along interstate highways in the western portion of the state. These pinch points likely constitute important conservation opportunities, where barriers to movement may cause disproportionate loss of connectivity, but also where actions such as placement of wildlife crossing structures or conservation easements could enhance connectivity and prevent detrimental impacts before they occur.
26

Applying Human-scale Understanding to Sensor-based Data : Generating Passive Feedback to Understand Urban Space Use

Eriksson, Adam, Uppling, Hugo January 2021 (has links)
The aim of this thesis is to investigate how parametrization of large-scale person movement data can contribute to describing the use of urban space. Given anonymous coordinate and timestamp data from a sensor observing an open-air mall, movement-based parameters are selected according to public life studies, behavioral mapping, and space syntax tools. The thesis aim is operationalized by answering how well the parametrizations perform in capturing urban space use, as well as investigating how the use is described when applying the parameterized data in selected urban space use tools. Also, the parameterized data are evaluated as time series to investigate possible further understanding of urban space use. The parametrization performance is evaluated by accuracy and F1-score and time series forecasts are evaluated by root mean square error (RMSE) and mean absolute error (MAE). The results indicate a parametrization accuracy of 93% or higher, while a high yet fluctuating F1 -score indicates that the parameterizations might be sensitive to imbalanced data, and that accuracy alone might not be sufficient when evaluating urban data. The parameterized data applied in the selected urban space use tools highlights the granularity achieved from sensor-based data. In the time series analysis, a Facebook Prophet forecast model is implemented, with an MAE of 8.6% and RMSE of 11.7%, outperforming a seasonal naïve forecast implementation with an MAE of 14.1% and RMSE of 18.8%. The thesis finds that time series modelling adds to understanding patterns and changes of use over time and that the approach could be developed further in future studies. In answering how the urban space is used, the thesis develops a new methodology. This methodology combines human-scale understanding of urban space use with large-scale data, generating citizen passive feedback. / Vikten av att förstå hur en plats, eller ett stadsrum, faktiskt används härstammar ur det faktum att användningen ofta avviker från vad som var planerat. Genom en utökad förståelse för användningen av en plats går det exempelvis att anpassa platsens utformning efter faktisk användning. För att uppnå denna djupare förståelse finns flera olika tillvägagångssätt. Ett sätt är att använda de analoga teorier och verktyg som under lång tid har utvecklats av arkitekter och stadsplanerare, med avsikt att förstå sig på människors beteenden i olika stadsrum. Dessa urbana analysverktyg innefattar exempelvis ramverk för att kartlägga människors aktivitet. Ett annat sätt är att analysera stora datamängder för att utvinna generella rörelsemönster eller detaljerade trender. I denna uppsats presenteras en metod som kombinerar dessa två tillvägagångssätt i syfte att väva in de analoga teoriernas mänskliga utgångspunkt med de möjligheter som uppstår vid analys av stora datamängder. Genom att utveckla algoritmer kan rörelse-baserad information utvinnas, eller parametriseras, ur data från människors rörelse. Metoden innebär i kontexten av denna studie således en parametrisering av rörelse-data från en sensor uppsatt på shoppinggatan Kompassen i Göteborg. Urvalet av parametriseringar har baserats på de urbana analysverktygen. Detta sammanfattas i studiens övergripande syfte: att undersöka hur parametrisering av storskalig rörelsedata kan bidra till att förklara användningen av stadsrum. För att uppnå detta syfte besvaras tre frågeställningar. Först utvärderas hur väl det parametriserade rörelsedatat kan fånga upp användningen av stadsrum. Sedan undersöks hur användningen gestaltas genom att det parametriserade datat appliceras i utvalda urbana analysverktyg. Till sist analyseras datat som tidsserier i syfte att undersöka hur en förståelse över tid kan öka förståelsen för användningen av stadsrum. Genom att utgå från rörelsedata utvanns personers hastighet, startpunkt, och destination. Vidare parametriserades klasserna butiksinteraktion, grupptillhörighet, och stillastående i enlighet med de urbana analysverktygen. Vid utvärdering av dessa tre klasser visar studiens resultat att användningen av stadsrummet fångas upp till hög grad och uppnår åtminstone 93% i precision. Dock visar resultaten även att träffsäkerheten minskar ju mer obalanserat datat är. Detta innebär att ju lägre frekvent en klass är i datat desto svårare är den att fånga upp.    När det parametriserade datat används i de urbana analysverktygen, visar resultaten att det utvunna datat bidrar med en högre upplösning som kan bana väg för ny förståelse för hur stadsrum används. Den högre upplösningen möjliggör även för tidsserieanalys av det parametriserade datat. Resultaten pekar på en mer detaljerad förståelse för trender och användningen av stadsrummet över tid. Till exempel implementeras verktyget Facebook Prophet som i detta fall prognostiserar andelen med grupptillhörighet. För en prognos på två veckor uppnås ett genomsnittligt absolutfel på 8.6%, vilket anses vara ett träffsäkert resultat. På så sätt medför möjligheten att prognostisera användning och identifiera avvikelser från trender ett ytterligare bidrag till förståelsen för hur platsen används. Tidsserieanalysen uppvisar stor potential och tolkningar från såväl tidsserierna som prognosmodeller har utrymme att vidareutvecklas. I framtida studier bör även algoritmer för fler aktivitetsbaserade parametrar, till exempel sittande eller samtalande, utvecklas. Uppsatsens fokus kretsar kring att skapa förståelse för hur ett stadsrum används och lämnar således frågan varför åt framtida studier, där resultat från denna studie kan fungera som viktigt underlag. Studiens metod tillför ett mänskligt perspektiv till stora datamängder och bidrar på så sätt till ett bredare underlag för hur stadsrum används. Med utgångspunkt i urbana analysverktyg har insamlad sensordata parametriserats till viktiga rörelse-baserade klasser. Detta underlag motsvarar en passiv återkoppling från användarna av stadsrummet som därigenom förklarar hur en plats faktiskt används.
27

Space Use and Annual Survival of Hybridized Mouflon Sheep in Hawaii and Comparing Estimates of Population Size through Instantaneous Sampling and Photographic Capture-Recapture

Adams, Bradley Jay 01 April 2019 (has links)
Significant efforts in conservation are devoted to the management and study of ungulates, due to their significant roles in ecosystems as well as their potential economic value. This is especially true for species considered exotic, such as mouflon sheep (Ovis musimon) in Hawaii. Effective management of an exotic species requires an understanding of ecological metrics such as space use, survival, and population size. We provided these metrics for a population of mouflon that have hybridized with feral sheep (Ovis aries) on the island of Hawaii. In Chapter 1, we quantified space use and annual survival of sheep in an area where sheep are managed for hunting opportunity. We determined that sheep have relatively small home-ranges and high rates of annual survival (>90%). In Chapter 2, we provided the first estimate of population size for the same study area while simultaneously testing the viability of a novel method of estimating population size, currently known as Instantaneous Sampling. Using photographic capture recapture as a comparison method, we compared estimates derived from both techniques and provided support for Instantaneous Sampling as an alternative method for estimating population size.
28

Spatial Ecology of Bobcats (Lynx rufus) in the Appalachian Mountains of Western Virginia

McNitt, David C. 27 August 2019 (has links)
Despite the prevalent distribution of bobcats in western Virginia and the broader region of Appalachia, there is a paucity of information on their spatial ecology in this region. Due to the unique ecological conditions of Appalachia, and increasing public interest surrounding the role of bobcats as predators in the region, there is a need for local information on bobcat ecology. I utilized data from 20 GPS collared bobcats (14M, 6F) to investigate bobcat spatial ecology in the mountains of Western Virginia. Average resident male home range size was 33.9 ± 2.6 km^2, nearly 3 times larger than average resident female home range size (12.1 ± 2.4 km^2). Seasonal areas of use did not differ in size among seasons, but exhibited minor shifts in location and shape. Average male movement rates (232.3 ± 12.0 meters/hour) were 1.5 times greater than average female movement rates (154.4 ± 8.9 meters/hour). Male movement rates increased during the dispersal season and female movement rates increased during the denning/kitten-rearing season. Second order resource selection analysis indicates that bobcats of both sexes select home ranges at higher elevations than expected at random, and that selection varies between sexes and among seasons. Third order resource selection analysis indicates that bobcats select for locations near open canopy structure, and avoid forest interior. These findings build upon previous findings regarding bobcat diet and population dynamics to provide a comprehensive understanding of basic bobcat ecology in western Virginia, and will inform further research investigating predator/prey interactions. / Master of Science / Despite the prevalent distribution of bobcats in western Virginia and the broader region of Appalachia, there is a paucity of information on their spatial ecology in this region. Due to the unique ecological conditions of Appalachia, and increasing public interest surrounding the role of bobcats as predators in the region, there is a need for local information on bobcat ecology. I utilized data from 20 GPS collared bobcats (14M, 6F) to investigate bobcat spatial ecology in the mountains of Western Virginia. I found that male bobcats use more space than females, with home ranges nearly 3 times larger and movement rates 1.5 times higher. I found that home ranges do not expand or contract throughout the year, but do shift in shape slightly. I found that bobcats select home ranges at higher elevations, indicating that home ranges are predominantly located on ridges. I found that selection of home ranges differed between sexes and seasons, indicating that shifts in home range shape throughout the year reflect varying habitat selection. Within their home ranges, I found that bobcats select for areas of open canopy resulting from fields, fire, and timber harvest; and avoid areas of forest interior. These findings build upon previous findings regarding bobcat diet and population dynamics to provide a comprehensive understanding of basic bobcat ecology in western Virginia, and will inform further research investigating predator/prey interactions.
29

Bat Resource Utilization Along the Potomac River Corridor in Maryland

Litterer, Amber Starr 15 April 2024 (has links)
In 2021, 17-year periodical cicadas (Magicicada spp.) in Brood X emerged throughout much of the eastern United States. Due to their abundance and lack of predator avoidance during their short six-week period on the above-ground landscape, many species of animals consume cicadas and in turn have short-term habitat use and population responses. The response of bats to periodical cicadas is largely unknown. Using a before-after-control-impact study design, we deployed ultrasonic acoustic detectors during the summers of 2020–2022 within and just outside the range of the cicada emergence along the Potomac River corridor of Maryland and Virginia. For total bat activity, there was significantly more acoustic activity within the range of the cicada emergence the year during and the year following emergence than where emergence did not occur. Additionally, for all individual species and phonic groups, bat activity increased the year during and year after the emergence within the range of periodical cicadas compared to the year prior to emergence. Our study demonstrates that periodical cicadas may serve as a resource pulse that can cause an increase in bat activity and suggests at least a short-term local to regional population increase from immigration the year during and from recruitment the year following. Bats of the mid-Atlantic have been negatively affected by numerous stressors including white-nose syndrome, wind turbine development, and land use change. One species suffering widespread population decline over the last decade in the mid-Atlantic has been the little brown bat (Myotis lucifugus). Understanding the space use and resource selection of remaining populations is critical for management and species recovery. Nevertheless, there are difficulties with studying the movement of insectivorous bats due to their small size and high vagility. Traditional foraging studies of Myotis spp. have used fixed station telemetry and associated multi-azimuthal observations to estimate the location of individuals. However, single azimuth observations are often unable to be included in these studies leading to more potential location estimates missing from movement models. During the summer of 2022, I radio-tagged little brown bats from a maternity colony along the Potomac River in Maryland and collected bearings on nine individuals using fixed station telemetry from sunset until bats returned to the maternity roost. Location estimates were obtained from both single and multi-azimuthal observations. I fit movement models for each individual and used auto-correlated kernel density estimation (AKDE) to estimate space use. I also assessed second and third order habitat selection of individual bats. The average 95% AKDE for males was 889 ha ± 424.6 and 699.3 ha ± 129 for adult females. I found bats had higher predicted use of habitat that was closer in distance to water and wetlands and further from open habitat at the second order and closer to water and open habitat at the third order of resource selection. Habitat associations were similar to previous little brown bat resource selection studies. However, estimates of space use were larger than those using other movement models. This study was novel in that it incorporated single azimuth observations and periodicity into models of space use, thereby increasing sample size and offering a new framework for future telemetry studies. These estimates of space use can be used by land managers to protect the habitat of this imperiled species. / Master of Science / In 2021, 17-year periodical cicadas (Magicicada spp.) in Brood X emerged throughout much of the eastern United States in high abundance. As an abundant food resource, many animals consume periodical cicadas while they are above ground during the summers. This has allowed for short-term population increases and changes in reproduction in some species. However, the response of bats to periodical cicadas is largely unknown. To study this, I deployed ultrasonic acoustic detectors that recorded six species/species groups of bats during the summers of 2020–2022 within and just outside the range of the cicada emergence along the Potomac River Corridor, Maryland, and Virginia. I observed significantly more total bat acoustic activity within the range of the cicada during the emergence year and the year following than where emergence did not occur. Also, for all individual species and species groups, bat activity increased in the year during and after the emergence within the range of periodical cicadas compared to the year before emergence. My study demonstrates that periodical cicadas cause an increase in bat activity and may suggest a population increase in the areas where the emergence has occurred. Bats of the mid-Atlantic have experienced population declines due to numerous stressors including white-nose syndrome caused by the fungus Pseudogymnoascus destructans, wind turbine development, and habitat fragmentation. One species that has been heavily affected by white-nose syndrome is the little brown bat (Myotis lucifugus). To help conserve the species, understanding their home range and their resource needs is critical. However, little brown bats are small and agile fliers which poses difficulties for tracking them. Traditional foraging studies of species in this genus have used telemetry to obtain triangulations and location estimates of individuals but often leave out data collected from a single bearing as it is difficult to calculate the true location of the animal. During the summer of 2022, I radio-tagged little brown bats from a maternity colony along the Potomac River in Maryland and collected bearings on nine individuals using fixed station telemetry from sunset until bats returned to the maternity roost. We estimated locations from both triangulations and single bearings. I calculated movement models for each individual and fit them to an auto-correlated kernel density estimator (AKDE) of space use. The average 95% auto-correlated kernel density estimates of space use (AKDE) for males was 889 ha ± 424.6 and 699.3 ha ± 129 for adult females. I also assessed the habitat selection of individuals within their home range and across the nearby landscape. I found that bats preferred to use areas closer to water and wetlands and preferred to use areas closer to open habitat within their home range but preferred to use areas further from open habitat across the landscape. Habitat associations were similar to previous little brown bat resource selection studies. However, estimates of space use were larger than those using other movement models. My study was novel in that it incorporated single azimuth observations and periodicity into models of space use, thereby increasing sample size and offering a new framework for future telemetry studies. These estimates of space use can be used by land managers to protect the habitat of this imperiled species.
30

Consideration of space debris in the life cycle assessment framework / Considération des débris spatiaux dans le cadre de l’analyse de cycle de vie

Maury, Thibaut 05 April 2019 (has links)
L’analyse de cycle de vie environnementale (ACV), d’après l’ISO 14040/44, a été identifiée par l’agence spatiale Européenne, ArianeGroup et plusieurs acteurs de l’industrie spatiale européenne comme la méthodologie la mieux adaptée pour réaliser l’évaluation environnementale des missions spatiales. Cependant, le secteur spatial est un domaine d’activité dont la particularité est de s’étendre au-delà des limites de l’environnement terrestre. Ainsi, s’il est possible d’évaluer les impacts sur l’environnement classique via la méthodologie ACV, les impacts générés sur l’environnement orbital ne sont aujourd’hui pas considérés dans son cadre de référence.Par conséquent, il s’agit ici d’étendre le champ des études ACV dans le domaine du spatial afin de caractériser les étapes du cycle de vie ayant lieu en orbite, c’est-à-dire la phase d’usage pendant la mission spatiale et la phase de fin de vie (ou Post-Mission Disposal). L’anticipation de cette dernière est devenue une étape cruciale dans la conception des missions spatiales du fait des règlementations visant à limiter la prolifération des débris spatiaux. En effet, seulement 6% de la population en orbite autour de la Terre sont des satellites actifs, le reste étant considéré comme des débris, résultat des missions et activités spatiales passées. Etant donné cet enjeu de durabilité majeur pour l'industrie spatiale, les études environnementales se doivent de mettre en évidence les transferts de pollution potentiels non seulement entre les impacts environnementaux classiques tels que Changement Climatique ou la Toxicité mais aussi ceux relatifs à l’environnement orbital, au premier rang desquels figurent les débris spatiaux.Afin de caractériser cet impact sur l’environnement orbital, nous proposons de définir une nouvelle catégorie d’impact en ACV dénommée ‘Orbital Space Use’. La conformité avec le cadre de référence de l’ACV est assurée au travers de la construction de chaines de cause-à-effet (ou impact pathways) reliant les flux élémentaires du système d’étude aux mécanismes environnementaux (indicateur midpoint) et au dommage final (indicateur endpoint) au sein de l’Aire de Protection ‘Ressources Naturelles’. En effet, les orbites proches de la Terre qui supportent les activités spatiales sont considérées à ce titre comme une ressource pouvant être impactée par des ‘stresseurs’. Les débris spatiaux sont aujourd’hui identifiés comme les principaux ‘stresseurs’ vis-à-vis de l’accès et de la pleine utilisation de la ressource orbitale. Ainsi, le développement d’un modèle de caractérisation a été entrepris. Il permet d’évaluer l’impact potentiel d’une mission spatiale sur la population des débris déjà présente en orbite. Les facteurs de caractérisation obtenus sont appliqués à un cas d’étude comparant trois scénarios de fin de vie différents dans le but de prouver l’applicabilité du modèle. En outre, une première approche s’intéressant à la quantification des externalités économiques négatives engendrées par la prolifération des débris est développée. Elle constitue une étape préliminaire en vue d’un développement d’une catégorie de dommage dite ‘endpoint’. Enfin, les challenges méthodologiques restants et les potentiels développements complémentaires sont abordés. / Several actors of or related to the European space industry, such as ArianeGroup and the European Space Agency (ESA), have identified life cycle assessment (according to ISO14040/44) as the most appropriate methodology to measure and minimise their environmental impact. Nevertheless, space systems deal with a strong particularity which adds new aspects considering the scope of the LCA framework. Space missions are the only human activity that crosses all segments of the atmosphere and stays “out” of the natural environment and ecosystems. Regarding space systems with a holistic approach, environmental impacts could occur not only in the conventional ecosphere but also in the outer space (i.e. the orbital environment).Consequently, the current scope of LCA studies should be broadened to take into account the on-orbit lifetime as well as the end-of-life disposal of the spacecraft. Yet, it is becoming a crucial point of the space mission design due to the future increase of the orbital population composed in a major part by space debris. In this way, LCA studies of space missions could indicate trade-offs not only between typical impact categories (toxicity and climate change for example) but also with regard to impacts generated in the orbital environment with a particular focus on space debris related impacts.Hence, the priority has been given to the integration of a new impact category called orbital space use in the life cycle impact assessment framework. To address the environmental burdens comprehensively in this new category, impact pathways linking elementary flows to environmental mechanisms (midpoint) and damages (endpoint) are developed within the Area-of-Protection ‘Natural resources’. Space debris is identified as the main stressor of the orbital environment. Thus, ‘characterisation factors’ are defined and calculated at midpoint level to assess the potential impact of a space mission on the orbital environment. The methodology is applied to a case study to prove its applicability: the potential impact of a theoretical space mission is addressed through the comparison of three disposal scenarios. Also, a first attempt regarding the characterisation of the endpoint damage is provided taking into account the economic externalities caused by space debris. Finally, remaining methodological challenges and perspectives for future work are provided.

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