959 resultados para Potential impacts
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Recent observed hydro-climatic changes in mountainous areas are of concern as they may directly affect capacity to fulfill water needs. The canton of Vaud in Western Switzerland is an example of such a region as it has experienced water shortage episodes during the past decade. Based on an integrated modeling framework, this study explores how hydro-climatic conditions and water needs could evolve in mountain environments and assesses their potential impacts on water stress by the 2060 horizon. Flows were simulated based on a daily semi-distributed hydrological model. Future changes were derived from Swiss climate scenarios based on two regional climate models. Regarding water needs, the authorities of the canton of Vaud provided a population growth scenario while irrigation and livestock trends followed a business-as-usual scenario. Currently, the canton of Vaud experiences moderate water stress from June to August, except in its Alpine area where no stress is noted. In the 2060 horizon, water needs could exceed 80% of the rivers' available resources in low- to mid-altitude environments in mid-summer. This arises from the combination of drier and warmer climate that leads to longer and more severe low flows, and increasing urban (+ 40%) and irrigation (+ 25%) water needs. Highlighting regional differences supports the development of sustainable development pathways to reduce water tensions. Based on a quantitative assessment, this study also calls for broader impact studies including water quality issues.
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Los efectos del cambio global sobre los bosques son una de las grandes preocupaciones de la sociedad del siglo XXI. Algunas de sus posibles consecuencias como son los efectos en la producción, la sostenibilidad, la pérdida de biodiversidad o cambios en la distribución y ensamblaje de especies forestales pueden tener grandes repercusiones sociales, ecológicas y económicas. La detección y seguimiento de estos efectos constituyen uno de los retos a los que se enfrentan en la actualidad científicos y gestores forestales. En base a la comparación de series históricas del Inventario Forestal Nacional Español (IFN), esta tesis trata de arrojar luz sobre algunos de los impactos que los cambios socioeconómicos y ambientales de las últimas décadas han generado sobre nuestros bosques. En primer lugar, esta tesis presenta una innovadora metodología con base geoestadística que permite la comparación de diferentes ciclos de inventario sin importar los diferentes métodos de muestreo empleados en cada uno de ellos (Capítulo 3). Esta metodología permite analizar cambios en la dinámica y distribución espacial de especies forestales en diferentes gradientes geográficos. Mediante su aplicación, se constatarán y cuantificarán algunas de las primeras evidencias de cambio en la distribución altitudinal y latitudinal de diferentes especies forestales ibéricas, que junto al estudio de su dinámica poblacional y tasas demográficas, ayudarán a testar algunas hipótesis biogeográficas en un escenario de cambio global en zonas de especial vulnerabilidad (Capítulos 3, 4 y 5). Por último, mediante la comparación de ciclos de parcelas permanentes del IFN se ahondará en el conocimiento de la evolución en las últimas décadas de especies invasoras en los ecosistemas forestales del cuadrante noroccidental ibérico, uno de los más afectados por la invasión de esta flora (Capítulo 6). ABSTRACT The effects of global change on forests are one of the major concerns of the XXI century. Some of the potential impacts of global change on forest growth, productivity, biodiversity or changes in species assembly and spatial distribution may have great ecological and economic consequences. The detection and monitoring of these effects are some of the major challenges that scientists and forest managers face nowadays. Based on the comparison of historical series of the Spanish National Forest Inventory (NFI), this thesis tries to shed some light on some of the impacts driven by recent socio-economic and environmental changes on our forest ecosystems. Firstly, this thesis presents an innovative methodology based on geostatistical techniques that allows the comparison of different NFI cycles regardless of the different sampling methods used in each of them (Chapter 3). This methodology, in conjunction with other statistical techniques, allows to analyze changes in the spatial distribution and population dynamics of forest species along different geographic gradients. By its application, this thesis presents some of the first evidences of changes in species distribution along different geographical gradients in the Iberian Peninsula. The analysis of these findings, of species population dynamics and demographic rates will help to test some biogeographical hypothesis on forests under climate change scenarios in areas of particular vulnerability (Chapters 3, 4 and 5). Finally, by comparing NFI cycles with permanent plots, this thesis increases our knowledge about the patterns and processes associated with the recent evolution of invasive species in the forest ecosystems of North-western Iberia, one of the areas most affected by the invasion of allien species at national scale (Chapter 6).
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The recent invasion of the European green crab (Carcinus maenas) populations in Placentia Bay, Newfoundland and Labrador (NL) raises great concern about potential impacts on local fisheries and native biodiversity. Green crab are highly adaptable and in both native and invaded areas, green crab are well established predators that can outcompete other similarly sized decapods. The main objectives of this thesis were to: 1) identify the native species that green crab compete with for resources; 2) determine the depths and substrate types in which these interactions likely occur; 3) assess the indirect effects of green crab on native crustaceans and their changes in behavior; 4) assess the impacts of green crab on benthic community structure; 5) compare the NL population with other Atlantic Canadian populations in terms of competitive abilities; and 6) compare morphological features of the NL population with other Atlantic Canadian populations. I found that green crab overlap in space and diet with both rock crab (Cancer irroratus) and American lobster (Homarus americanus), potentially leading to a shift in habitat. Laboratory studies on naïve juvenile lobster also suggested shifts in behavior related to green crab, in that lobster decreased foraging activity and increased shelter use in the presence of green crab. Benthic community analyses showed fewer species in mud, sand, and eelgrass sites heavily populated by green crab compared to sites without green crab, although results depended on the taxa involved and I could not eliminate environmental differences through a short term caging study. Foraging ability of green crab varied in intraspecific competition experiments, with populations from NL and Prince Edward Island dominating longer-established populations from Nova Scotia and New Brunswick. Additional studies excluded claw size as a factor driving these results and behavioral differences likely reflected differences in invasion time and population genetics. Overall, green crab in Placentia Bay appear to be altering community structure of benthic invertebrates through predation and they also appear to indirectly impact native crustaceans through competition.
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Shelf seas comprise approximately 7% of the world’s oceans and host enormous economic activity. Development of energy installations (e.g. Offshore Wind Farms (OWFs), tidal turbines) in response to increased demand for renewable energy requires a careful analysis of potential impacts. Recent remote sensing observations have identified kilometrescale impacts from OWFs. Existing modelling evaluating monopile impacts has fallen into two camps: small-scale models with individually resolved turbines looking at local effects; and large-scale analyses but with sub-grid scale turbine parameterisations. This work straddles both scales through a 3D unstructured grid model (FVCOM): wind turbine monopiles in the eastern Irish Sea are explicitly described in the grid whilst the overall grid domain covers the south-western UK shelf. Localised regions of decreased velocity extend up to 250 times the monopile diameter away from the monopile. Shelf-wide, the amplitude of the M2 tidal constituent increases by up to 7%. The turbines enhance localised vertical mixing which decreases seasonal stratification. The spatial extent of this extends well beyond the turbines into the surrounding seas. With significant expansion of OWFs on continental shelves, this work highlights the importance of how OWFs may impact coastal (e.g. increased flooding risk) and offshore (e.g. stratification and nutrient cycling) areas.
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Shelf seas comprise approximately 7% of the world’s oceans and host enormous economic activity. Development of energy installations (e.g. Offshore Wind Farms (OWFs), tidal turbines) in response to increased demand for renewable energy requires a careful analysis of potential impacts. Recent remote sensing observations have identified kilometrescale impacts from OWFs. Existing modelling evaluating monopile impacts has fallen into two camps: small-scale models with individually resolved turbines looking at local effects; and large-scale analyses but with sub-grid scale turbine parameterisations. This work straddles both scales through a 3D unstructured grid model (FVCOM): wind turbine monopiles in the eastern Irish Sea are explicitly described in the grid whilst the overall grid domain covers the south-western UK shelf. Localised regions of decreased velocity extend up to 250 times the monopile diameter away from the monopile. Shelf-wide, the amplitude of the M2 tidal constituent increases by up to 7%. The turbines enhance localised vertical mixing which decreases seasonal stratification. The spatial extent of this extends well beyond the turbines into the surrounding seas. With significant expansion of OWFs on continental shelves, this work highlights the importance of how OWFs may impact coastal (e.g. increased flooding risk) and offshore (e.g. stratification and nutrient cycling) areas.
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Several environmental stressors can impact the physiology and survival of fishes. Fish experience natural fluctuations in temperature and dissolved oxygen, but variations in these parameters due to anthropogenic sources are typically greater in magnitude and duration. Changes in temperature and oxygen of anthropogenic origins may therefore have larger negative impacts on fish than those occurring during natural events. Physiological parameters are sensitive indicators of the impacts of stressors by providing insight into the manner in which fish are disturbed by the stressor. Fish may display cumulative physiological responses to successive stressors, but the concept of synergy among multiple thermal stressors is poorly understood. Further, some fish species can be subjected to competitive angling events, which expose fish to an array of additional stressors that can increase mortality. The impacts of these events may change over seasons as fish display seasonal changes in behavior and physiology. Latitudinal origin may also affect the physiological response and mortality of fish exposed to common environmental stressors as individual populations are adapted to local environmental conditions. This thesis focuses on addressing these potential impacts on physiological parameters and mortality of largemouth bass (Micropterus salmoides) and provides implications for management and conservation. Largemouth bass were relatively robust to abrupt changes in temperature and oxygen, but were perturbed from physiological homeostasis during large (12°C) temperature shocks and low (< 4 mg O2/L) levels of dissolved oxygen. Cumulative physiological impacts of multiple cold shocks were only slightly greater than the disturbances sustained during a single cold shock, suggesting largemouth bass are able to tolerate successive thermal stressors. Largemouth bass exhibited seasonal changes in physiological parameters but the responses of fish to angling tournaments were relatively similar across seasons when compared with seasonal controls. Mortality was low during angling tournaments held during four seasons and no apparent seasonal trends were observed. Lastly, largemouth bass from two latitudinally separated populations exhibited differences in their physiological responses to acute cold stressors and overwinter mortality, characterized by greater mortality and physiological disturbances of southern fish than northern fish. Knowledge gained from this study can be used to make management and conservation decisions regarding a host of environmental factors and provides insight into the mechanisms by which fish species can persist over large latitudinal ranges.
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The European Capital of Culture is an annual mega-event, which can provide a good forum though which to challenge and engage local citizens, thus generating feelings of common citizenship. In addition, it presents an ideal opportunity to promote the restructuring of the hosting urban space. However, the success of both the organization and the city that hosts the cultural event depends on the residents’ commitment towards it, the consistency of the tourism attractions and activities supplied, and the capacity of anticipating and monitoring the evolution of tourists’ preferences. The present study aims to assess the intention to participate and the impacts perceived by residents of Guimarães from hosting one of the 2012 European Capitals of Culture (2012 ECOC) in the ex-ante period (2011). Through a convenience sample of 471 usable surveys applied to the local population, conducted between October and December 2011, we tried to identify some of these potential impacts. According to the results received, 40% of residents had a low or very low knowledge of the cultural program, although only 11% demonstrated no intention of attending any activity during the event. The comparison of the mean scores of the expected 2012 ECOC impacts by gender reveals that the most valued and least valued factors are common to female and male respondents. With regard to the differences between those that intended to attend the event and the ones that did not, expected participants rated positive and negative impact factors more than did the ones that did not intend to attend.
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The European Capital of Culture is an annual mega-event, which can provide a good forum though which to challenge and engage local citizens, thus generating feelings of common citizenship. In addition, it presents an ideal opportunity to promote the restructuring of the hosting urban space. However, the success of both the organization and the city that hosts the cultural event depends on the residents’ commitment towards it, the consistency of the tourism attractions and activities supplied, and the capacity of anticipating and monitoring the evolution of tourists’ preferences. The present study aims to assess the intention to participate and the impacts perceived by residents of Guimarães from hosting one of the 2012 European Capitals of Culture (2012 ECOC) in the ex-ante period (2011). Through a convenience sample of 471 usable surveys applied to the local population, conducted between October and December 2011, we tried to identify some of these potential impacts. According to the results received, 40% of residents had a low or very low knowledge of the cultural program, although only 11% demonstrated no intention of attending any activity during the event. The comparison of the mean scores of the expected 2012 ECOC impacts by gender reveals that the most valued and least valued factors are common to female and male respondents. With regard to the differences between those that intended to attend the event and the ones that did not, expected participants rated positive and negative impact factors more than did the ones that did not intend to attend.
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Dissertação de Mestrado em Gestão e Conservação da Natureza.
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Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs), which obtain their fuel from the grid by charging a battery, are set to be introduced into the mass market and expected to contribute to oil consumption reduction. This research is concerned with studying the potential impacts on the electric utilities of large-scale adoption of plug-in electric vehicles from the perspective of electricity demand, fossil fuels use, CO2 emissions and energy costs. Simulations were applied to the Portuguese case study in order to analyze what would be the optimal recharge profile and EV penetration in an energy-oriented, an emissions-oriented and a cost-oriented objective. The objectives considered were: The leveling of load profiles, minimization of daily emissions and minimization of daily wholesale costs. Almost all solutions point to an off-peak recharge and a 50% reduction in daily wholesale costs can be verified from a peak recharge scenario to an off-peak recharge for a 2 million EVs in 2020. A 15% improvement in the daily total wholesale costs can be verified in the costs minimization objective when compared with the off-peak scenario result.
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Dissertation to obtain the degree of Doctor in Electrical and Computer Engineering, specialization of Collaborative Networks
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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.
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Dissertação de mestrado integrado em Engenharia e Gestão de Sistemas de Informação
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Continental-scale assessments of 21st century global impacts of climate change on biodiversity have forecasted range contractions for many species. These coarse resolution studies are, however, of limited relevance for projecting risks to biodiversity in mountain systems, where pronounced microclimatic variation could allow species to persist locally, and are ill-suited for assessment of species-specific threat in particular regions. Here, we assess the impacts of climate change on 2632 plant species across all major European mountain ranges, using high-resolution (ca. 100 m) species samples and data expressing four future climate scenarios. Projected habitat loss is greater for species distributed at higher elevations; depending on the climate scenario, we find 36-55% of alpine species, 31-51% of subalpine species and 19-46% of montane species lose more than 80% of their suitable habitat by 2070-2100. While our high-resolution analyses consistently indicate marked levels of threat to cold-adapted mountain florae across Europe, they also reveal unequal distribution of this threat across the various mountain ranges. Impacts on florae from regions projected to undergo increased warming accompanied by decreased precipitation, such as the Pyrenees and the Eastern Austrian Alps, will likely be greater than on florae in regions where the increase in temperature is less pronounced and rainfall increases concomitantly, such as in the Norwegian Scandes and the Scottish Highlands. This suggests that change in precipitation, not only warming, plays an important role in determining the potential impacts of climate change on vegetation.
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El Parc Natural de l’Alt Pirineu (PNAP) està creant una xarxa d’itineraris d’educació ambiental amb l’objectiu de divulgar els valors del parc i conscienciar els seus visitants sobre la importància de conservar el medi ambient. El desenvolupament de mètodes de valoració de l’aptitud de potencials itineraris d’educació ambiental pot servir per crear eines de gestió molt útils a l’hora d’ampliar aquesta xarxa de senders. Per aquest motiu, un grup anterior de la llicenciatura de Ciències Ambientals va desenvolupar el preprotocol Neret, que permet obtenir una puntuació numèrica per a un itinerari, responent a una sèrie de preguntes senzilles. En el present projecte, s’ha aplicat el protocol anterior a tres itineraris de muntanya per tal d’estudiar-ne el funcionament en un tipus d’itinerari diferent dels de fons de vall, on va ser dissenyat. L’anàlisi del preprotocol s’ha efectuat mitjançant una matriu DAFO, a partir de la qual s’han proposat una sèrie d’estratègies de millora i, a partir d’aquestes, s’ha desenvolupat un nou mètode de valoració. Els principals aspectes negatius del preprotocol són la seva manca de flexibilitat, la sobrevaloració dels criteris relacionats amb la dificultat del recorregut, la manca de detall en l’anàlisi del potencial interpretatiu dels itineraris a més del poc pes que té aquest criteri en la puntuació global i, finalment, l’absència d’un criteri que valori els potencials impactes que es podrien derivar de l’ús de l’itinerari. Aquestes mancances s’han mirat de corregir al mètode de valoració dissenyat en el present projecte mitjançant les següents aportacions: una estructura transversal dividida en quatre factors avaluats per separat, sense criteris de valoració excloents i amb una ponderació final dels quatre principals criteris modificable segons els objectius dels gestors; una valoració més detallada dels continguts de l’itinerari, i finalment, la inclusió d’un nou criteri que considera la vulnerabilitat del medi a qualsevol tipus d’impacte.