Increasingly wildlife managers and land managers are challenged to maintain the viability and connectivity among large mammal populations. Thus, it is important that effective highway crossings are identified and optimized with respect to construction cost, facilitation of ungulate movements, and ability to reduce wildlife-vehicle collisions. The use of exclusion fencing to reduce ungulate-vehicle collisions is commonly installed along Swedish highways. However, exclusion fences may pose a threat to the viability of wildlife populations because they serve as barriers to individual movements and may limit accessibility to resources. Various types of wildlife crossings intended to reduce road-kills and increase habitat connectivity across fenced highways have been constructed throughout the world. Previous studies have evaluated the importance of structure design and size for many ungulate species, but few studies involved moose (Alces alces) which is the target species for most large ungulate mitigations in Sweden. The results of the studies are intended to facilitate the development of wildlife crossings and conventional road passages to meet ungulate demands. We monitored moose fitted with GPS radio collars and characterized their space and habitat use patterns in southwestern Sweden. Moose had seasonal differences in habitat selection within their home range, and generally preferred clear-cuts and early successional forest, boreal forest, and glades, but avoided agricultural areas and open water. We used infrared remote cameras, track surveys, and GPS telemetry to monitor the use of wildlife crossings and conventional road passages by moose and roe deer (Capreolus capreolus). The upgrading of a non-fenced road to a fenced highway with three wildlife crossings decreased the moose movements across the highway by 67-89 %. Overpass use by moose and roe deer declined with increased traffic volume on the highway and both species walked during periods of low highway traffic volumes and shifted to trotting as traffic intensity increased. Low rates of human disturbances and proximity to forest edges increased use of highway underpasses by roe deer. Moose used large underpasses to a higher degree than small.

Atropelamentos de animais silvestres são a principal causa de mortalidade de origem antrópica de vertebrados terrestres. Além da mortalidade direta, as populações animais também são fragmentadas e isoladas por rodovias, que podem atuar como filtro ou barreira ao movimento da fauna. A indicação e implementação de medidas mitigadoras têm sido uma estratégia cada vez importante, ampliando a necessidade de desenvolver e qualificar métodos para avaliar os impactos e indicar áreas prioritárias. Essa tese de doutorado foi concebida com a preocupação de investigar certos temas relacionados à mortalidade e fragmentação por rodovias. No primeiro capítulo, discuto como a qualificação da pesquisa e do licenciamento podem colaborar com este cenário. No segundo capítulo, apresento uma revisão de diferentes métodos de análise espacial utilizados para testar se existe a presença de agregações de atropelamento e para localizar onde estão estas agregações. No terceiro capítulo, apresento os resultados de um modelo de simulação baseado em indivíduos, que mostra que a localização dos hotspots muda ao longo do tempo em função da diminuição das populações próximas a trechos de rodovias com maior letalidade, o que torna a mortalidade per capita um melhor indicador da necessidade de mitigação. No último capítulo avaliei o efeito da rede de rodovias na fragmentação de habitat nos campos sulinos do Rio Grande do Sul, e demonstro que considerar o efeito da rede de rodovias como uma barreira aos movimentos da fauna modifica de forma severa a percepção que temos sobre o status de conservação dos campos. Esta tese pode ter dois tipos principais de implicações: a aplicação direta dos resultados aqui apresentados nas avaliações dos impactos de rodovias e planejamento da mitigação, e a influência em novos rumos de pesquisa na ecologia de rodovias. / Roads are responsible for a series of impacts to ecosystems, and some authors point out that road-kills are the main cause of terrestrial vertebrate mortality from anthropogenic causes. Besides direct mortality, wildlife populations are also fragmented and isolated by roads, as they can act as barriers or filters to wildlife movement. Implementing mitigation measures had become an important conservation strategy, but the need to prioritize areas brings the urgency to develop and qualify methods to assess road impacts and indicate priority areas. This doctorate thesis was developed with the concern of investigating subjects related to wildlife mortality and fragmentation by roads. In the first chapter I discuss how qualifying research and environmental licensing may contribute in this scenario. In the second chapter, I present a review of different methods of spatial analysis that have been used to test the presence of clustering on road-kill data and to identify road-kill hotpots. In the third chapter, I present the results of simulations of an individual-based model that shows that the location of road-kill hotspots change in time due to population depression near high-risk road segments; making per capita mortality a better indicator of the need for mitigation. In the last chapter, I evaluated the effect of the road network on habitat fragmentation of South Brazilian grasslands in Rio Grande do Sul State, and I show that considering the road network as a barrier changes severely our perception about grassland conservation status. This thesis may have two types of implications: the direct applications of the results presented here in environmental impact assessment of roads and in mitigation planning, or the influence on new paths to study road effects on wildlife.

Atropelamentos de animais silvestres são a principal causa de mortalidade de origem antrópica de vertebrados terrestres. Além da mortalidade direta, as populações animais também são fragmentadas e isoladas por rodovias, que podem atuar como filtro ou barreira ao movimento da fauna. A indicação e implementação de medidas mitigadoras têm sido uma estratégia cada vez importante, ampliando a necessidade de desenvolver e qualificar métodos para avaliar os impactos e indicar áreas prioritárias. Essa tese de doutorado foi concebida com a preocupação de investigar certos temas relacionados à mortalidade e fragmentação por rodovias. No primeiro capítulo, discuto como a qualificação da pesquisa e do licenciamento podem colaborar com este cenário. No segundo capítulo, apresento uma revisão de diferentes métodos de análise espacial utilizados para testar se existe a presença de agregações de atropelamento e para localizar onde estão estas agregações. No terceiro capítulo, apresento os resultados de um modelo de simulação baseado em indivíduos, que mostra que a localização dos hotspots muda ao longo do tempo em função da diminuição das populações próximas a trechos de rodovias com maior letalidade, o que torna a mortalidade per capita um melhor indicador da necessidade de mitigação. No último capítulo avaliei o efeito da rede de rodovias na fragmentação de habitat nos campos sulinos do Rio Grande do Sul, e demonstro que considerar o efeito da rede de rodovias como uma barreira aos movimentos da fauna modifica de forma severa a percepção que temos sobre o status de conservação dos campos. Esta tese pode ter dois tipos principais de implicações: a aplicação direta dos resultados aqui apresentados nas avaliações dos impactos de rodovias e planejamento da mitigação, e a influência em novos rumos de pesquisa na ecologia de rodovias. / Roads are responsible for a series of impacts to ecosystems, and some authors point out that road-kills are the main cause of terrestrial vertebrate mortality from anthropogenic causes. Besides direct mortality, wildlife populations are also fragmented and isolated by roads, as they can act as barriers or filters to wildlife movement. Implementing mitigation measures had become an important conservation strategy, but the need to prioritize areas brings the urgency to develop and qualify methods to assess road impacts and indicate priority areas. This doctorate thesis was developed with the concern of investigating subjects related to wildlife mortality and fragmentation by roads. In the first chapter I discuss how qualifying research and environmental licensing may contribute in this scenario. In the second chapter, I present a review of different methods of spatial analysis that have been used to test the presence of clustering on road-kill data and to identify road-kill hotpots. In the third chapter, I present the results of simulations of an individual-based model that shows that the location of road-kill hotspots change in time due to population depression near high-risk road segments; making per capita mortality a better indicator of the need for mitigation. In the last chapter, I evaluated the effect of the road network on habitat fragmentation of South Brazilian grasslands in Rio Grande do Sul State, and I show that considering the road network as a barrier changes severely our perception about grassland conservation status. This thesis may have two types of implications: the direct applications of the results presented here in environmental impact assessment of roads and in mitigation planning, or the influence on new paths to study road effects on wildlife.

Atropelamentos de animais silvestres são a principal causa de mortalidade de origem antrópica de vertebrados terrestres. Além da mortalidade direta, as populações animais também são fragmentadas e isoladas por rodovias, que podem atuar como filtro ou barreira ao movimento da fauna. A indicação e implementação de medidas mitigadoras têm sido uma estratégia cada vez importante, ampliando a necessidade de desenvolver e qualificar métodos para avaliar os impactos e indicar áreas prioritárias. Essa tese de doutorado foi concebida com a preocupação de investigar certos temas relacionados à mortalidade e fragmentação por rodovias. No primeiro capítulo, discuto como a qualificação da pesquisa e do licenciamento podem colaborar com este cenário. No segundo capítulo, apresento uma revisão de diferentes métodos de análise espacial utilizados para testar se existe a presença de agregações de atropelamento e para localizar onde estão estas agregações. No terceiro capítulo, apresento os resultados de um modelo de simulação baseado em indivíduos, que mostra que a localização dos hotspots muda ao longo do tempo em função da diminuição das populações próximas a trechos de rodovias com maior letalidade, o que torna a mortalidade per capita um melhor indicador da necessidade de mitigação. No último capítulo avaliei o efeito da rede de rodovias na fragmentação de habitat nos campos sulinos do Rio Grande do Sul, e demonstro que considerar o efeito da rede de rodovias como uma barreira aos movimentos da fauna modifica de forma severa a percepção que temos sobre o status de conservação dos campos. Esta tese pode ter dois tipos principais de implicações: a aplicação direta dos resultados aqui apresentados nas avaliações dos impactos de rodovias e planejamento da mitigação, e a influência em novos rumos de pesquisa na ecologia de rodovias. / Roads are responsible for a series of impacts to ecosystems, and some authors point out that road-kills are the main cause of terrestrial vertebrate mortality from anthropogenic causes. Besides direct mortality, wildlife populations are also fragmented and isolated by roads, as they can act as barriers or filters to wildlife movement. Implementing mitigation measures had become an important conservation strategy, but the need to prioritize areas brings the urgency to develop and qualify methods to assess road impacts and indicate priority areas. This doctorate thesis was developed with the concern of investigating subjects related to wildlife mortality and fragmentation by roads. In the first chapter I discuss how qualifying research and environmental licensing may contribute in this scenario. In the second chapter, I present a review of different methods of spatial analysis that have been used to test the presence of clustering on road-kill data and to identify road-kill hotpots. In the third chapter, I present the results of simulations of an individual-based model that shows that the location of road-kill hotspots change in time due to population depression near high-risk road segments; making per capita mortality a better indicator of the need for mitigation. In the last chapter, I evaluated the effect of the road network on habitat fragmentation of South Brazilian grasslands in Rio Grande do Sul State, and I show that considering the road network as a barrier changes severely our perception about grassland conservation status. This thesis may have two types of implications: the direct applications of the results presented here in environmental impact assessment of roads and in mitigation planning, or the influence on new paths to study road effects on wildlife.

A modificação de padrões espaciais de uso da terra geram consequências para os indivíduos, espécies, comunidades e ecossistemas. A expansão da malha viária e intensificação do tráfego nas estradas influenciam a conectividade da paisagem e comprometem processos ecológicos. A incorporação dos efeitos das estradas sobre a biodiversidade nas análises da paisagem propicia a compreensão dos impactos resultantes e subsidiam a escolha de medidas de mitigação adequadas. Pouco se sabe sobre a magnitude dos efeitos das estradas sobre a biodiversidade nos Neotrópicos, o que dificulta a elaboração de diretrizes para a implantação de estradas juntamente com a mitigação de seus impactos. Estudos que avaliem a permeabilidade das estradas são muito necessários no atual cenário de crescente implantação de empreendimentos lineares. Partindo do princípio de que é essencial manter ou restabelecer a conectividade da paisagem e dos fluxos biológicos, o presente trabalho buscou analisar a estrutura da paisagem no Mosaico da Cantareira (SP, Brasil) considerando as rodovias existentes na região e sua influência potencial para a conectividade entre os remanescentes florestais. Esta região circunscreve importantes unidades de conservação de proteção integral do Mosaico da Cantareira, composto por formações da Mata Atlântica. No Capítulo I, há uma análise sobre a conservação da biodiversidade em paisagens fragmentadas, considerando diferentes potenciais de influência das estradas sobre a conectividade dos remanescentes na paisagem. No Capítulo II, é proposto um índice de permeabilidade das rodovias em relação a cinco grupos taxonômicos de fauna a partir de dados obtidos através da consulta a especialistas. Algumas proposições e inferências pertinentes ao efeito de borda e ao efeito barreira das estradas sugerem que as pesquisas futuras se dediquem a propor medidas de mitigação ou compensação das interferências causadas pelas estradas na paisagem. Algumas métricas de paisagem permitem a incorporação de efeitos conhecidos, mesmo com a ausência de dados empíricos locais. O conhecimento acumulado por especialistas em grupos taxonômicos da fauna constitui uma fonte de informação muito relevante, mesmo com a incerteza e subjetividade inerentes a este tipo de informação. As principais características da paisagem na escala local que afetaram diretamente a permeabilidade das estradas foram intensidade de tráfego, gerando ruído e luminosidade, topografia local, presença de passagens funcionais, de habitat nos lados da via e de corpos dágua. Foi detectada uma variação da permeabilidade das estradas entre os grupos taxonômicos, principalmente devido à estratégia e capacidade de locomoção de cada um. Este resultado demonstra que é necessário condicionar a inclusão de infraestruturas de passagens mais generalistas que contemplem uma gama variada de grupos taxonômicos e grupos funcionais. Devem ser adotadas medidas mitigadoras para efeitos possíveis das estradas, mesmo que não haja uma comprovação empírica, para que seu monitoramento gere informações mais precisas em longo prazo. Ecólogos devem ser consultados a respeito do planejamento, pavimentação e ampliação de estradas, para auxiliar decisões imediatas e gerar protocolos que preencham as lacunas e contemplem delineamentos pertinentes para análises de longo prazo. / Changes in spatial patterns of land use have consequences for individuals, species, communities and ecosystems. Road network expansion and traffic intensification affect landscape connectivity and threat ecological processes. Incorporating road effects on biodiversity in landscape analysis improves the choice of adequate mitigation measures for the resulting impacts. Little is known about the magnitude of road effects on neotropical biodiversity, for this reason elaborating guidelines for road construction and mitigation is difficult. The current scenery of increasing linear enterprises requires information about road permeability. Assuming its essential for biodiversity conservation to maintain or reestablish landscape connectivity and biological flow, this research analyzed landscape structure in the Cantareira Mosaic of protected areas (São Paulo, Brazil) considering existing roads and their potential influence over forest remnants connectivity. This region includes important natural reserves with Brazilian Atlantic Forest remnants. In Chapter I, we analyze biodiversity conservation in fragmented landscapes considering various potential road influences on landscape connectivity. In Chapter II, we propose the Road Permeability Index based on expert knowledge of five fauna taxa with different mobility. Several propositions and inferences concerning edge and barrier effects of roads suggest that future research should propose mitigation and compensation measures to prevent road interference on landscape. It is plausible to incorporate known road effects to some landscape metrics even without empirical local data. In this sense, expert knowledge about wildlife constitutes a relevant source of information regardless its uncertainty. Traffic intensity, its noise and light, topography, crossing structures, habitat and water bodies were the main landscape features with local effect on road permeability. A variation in road permeability was identified between the five taxa considered in the study case mainly due to their kind of mobility. This demonstrates the necessity of adoption of more general crossing structures to embrace different groups of organisms. Other mitigation measures must be adopted based on possible impacts regardless empirical data so that their monitoring may generate this detailed information in the long term. Ecologists must be consulted during road planning and in case of widening and paving of roads. These experts can assist decisions and provide protocols to fill in knowledge gaps and suggest pertinent monitoring and experimental designs for long term analysis.

Les matériaux polymères ont connu un essor considérable dans le milieu du bâtiment depuis de nombreuses années, du fait d'un large panel de propriétés. Ces matériaux sont cependant très sensibles à la température et peuvent être facilement inflammables, permettant le développement d'un incendie. Du fait de la mise en place de normes de plus en plus strictes, relatives à la sécurité vis-à-vis d'un feu, il est nécessaire de mettre au point des systèmes retardateurs de flamme de plus en plus performants.Le premier objectif de la thèse est d'étudier les mécanismes retardateurs de flamme de composites EVA/ATH, et en particulier l'effet barrière. La notion de compacité de la couche de particules a pu être mise en évidence via l'essai de compression oedométrique. La mesure de la résistance à la compression d'une poudre, ou d'un mélange, permet d'estimer l'efficacité de l'effet barrière dans le cas de composites EVA/ATH.Le second objectif s'est concentré sur la caractérisation de nouvelles charges pouvant améliorer le comportement au feu de l'EVA. Dans un premier temps, de la diatomite a été introduite, jouant le rôle d'agent de synergie avec l'ATH. Dans un second temps, de la colémanite et des fondants broyés ont été introduits afin d’améliorer la cohésion de la couche barrière et du résidu de combustion par vitrification. La colémanite s’est révélée être un retardateur de flamme efficace, du fait de la libération d’eau de façon endothermique, et d’une vitrification à haute température. Dispersés dans la masse, les fondants perturbent la formation de la couche barrière du fait de la coagulation des particules. En tant que couche supérieure d’un système coeur-peau, le fondant vitrifie lors du refroidissement de l’échantillon, assurant la cohésion du résidu, ainsi qu’un rôle de suppresseur de fumées.Finalement, le dernier objectif de la thèse est de traiter des ATH, afin d’améliorer les propriétés mécaniques et retardatrices de flamme de l’EVA. Des molécules de greffage ont été réalisées à partir de MAPC1. La présence d’un copolymère p(MMA-co-MAPC1(OH)2) à la surface des particules homogénéise la dispersion de l’ATH dans la matrice EVA, améliorant les propriétés d’allongement à la rupture du composite. Un homopolymère p(MAPC1(OH)2) permet également d’améliorer la dispersion et l’allongement à la rupture. De plus, les groupements phosphorés présents le long de la chaîne semblent capables d’agir en phase condensée en tant que promoteur de charbonnement, ainsi qu’en phase gazeuse par le biais de radicaux réactifs. / Polymeric materials are booming for many years in the building industry, due to a wide range of properties. However, those materials are particularly heat sensitive and may be easily flammable, contributing to the development of a fire. Because of the implementation of more strict standards related to fire safety, the elaboration of more and more efficient fire retardant systems is necessary.The first goal of this thesis is to study the fire retardant mechanisms of EVA/ATH composites, and particularly the barrier effect. The role of the packing fraction of the particles layer was assessed used the oedometric compression test. The measurement of the resistance to compression of a powder, or a combination, can be used to estimate the efficiency of the barrier effect for EVA/ATH composites.The second goal has focused on the characterization of new fillers in order to improve the fire behavior of the EVA copolymer. Firstly, diatomite was introduced as a synergistic agent with ATH. In a second time, ground colemanite and glass frits were introduced in order to improve the cohesion of the barrier layer and the residue of combustion by vitrification. Colemanite seems to be an efficient fire retardant, because of the endothermic reaction associated with the release of structural water, and a vitrification at high temperature. When the glass frits are introduced in EVA/ATH composites, the formation of the barrier layer is disrupted because of the coagulation of particles. As an upper layer in a skin-core structure, the glass frit vitrifies during the cooling of the sample, improving the cohesion of the residue and acting as a smoke suppressor.Finally, the last goal of this thesis was to functionalize ATH, to improve mechanical and fire retardant properties of EVA. Surface treatment molecules were synthetized, based on a phosphonated monomer, the MAPC1. The presence of a p(MMA-co-MAPC1(OH)2) copolymer at the surface of particles improves the filler dispersion in the matrix, enhancing the elongation at break. The grafting using a p(MAPC1(OH)2) homopolymer also improves the filler dispersion and the elongation at break. Moreover, the phosphorus based functions along the molecular chain, seem to act in condensed phase as a char promoter, and in gaseous phase by means of reactive radicals.

As Si-manufacturing compatible SiGe HBTs are making rapid in-roads into RF through mm-wave circuit applications, with performance levels steadily marching upward, the use of these devices under extreme environment conditions are being studied extensively. In this work, test structures of SiGe HBTs were designed and put into extremely low temperatures, and a new negative differential resistance effect and a novel collector current kink effect are investigated in the cryogenically-operated SiGe HBTs. Theory based on an enhanced positive feedback mechanism associated with heterojunction barrier effect at deep cryogenic temperatures is proposed. The accumulated charge induced by the barrier effect acts at low temperatures to enhance the total collector current, indirectly producing both phenomena. This theory is confirmed using calibrated 2-D DESSIS simulations over temperature. These unique cryogenic effects also have significant impact on the ac performance of SiGe HBTs operating at high-injection. Technology evolution plays an important role in determining the magnitude of the observed phenomena, and the scaling implications are addressed. Circuit implication is discussed.

As the title implies, the chief goal of the present work is the improvement of the barrier effects of textile fabrics in the medical sector, in particular, in the operating room, which would be an effective safeguard against the causative pathogens allowing the health workers to work in and around hostile atmospheres and to accomplish useful tasks. To overcome the inherent drawbacks of surgical gown from classical fibers of both natural and synthetic origins, polyester micro filament fabric, down to 0.62 dtex per filament, was used to substitute them. Two major pathways have been chosen to render the surface hydrophobic: - Wet-chemical treatment - Plasma modification For the maximum efficiency of a specific wet-chemical, the following application formulations were found to be best effective: pH =4-5 Drying temperature and time=100°C / 90s Pick-up = 80% Curing temperature and time= 160°C / 120s A range of physical and chemical parameters have been found exerting significant influence on the extent of modification of the material: - Wetting agent - Amount of fluorine content in the chemical - Subsequent heat treatment of the finished material after washing - Ironing of the fabric For the plasma enhanced surface fluorination the following plasma gases were used: - Saturated fluorine compounds: CF4 and C2F6 - Reducing agent: H2 and C2H4 The exposure of the substrate to a pure C2F6 discharge resulted in higher hydrophobicity than the substrates exposed to CF4 plasma. Stepwise increased mixture of H2 or C2H4 to a proportionally decreased amount of C2F6 plasma showed a gradual decrease in contact angle and a substantial increase in sliding angle values. In addition to the treatments with gas mixtures a two-step technique, i.e., treatment with C2H4 prior to C2F6 plasma, was applied that appeared to be very promising in modifying the surface characteristics. Both, the contact angles and the sliding angles remaining almost constant on a very high level with increasing amount of C2H4 in the feed composition. An essentially vital concern of the work was the characterization of the treatment effect comprising both physical and chemical aspects. By washing the materials for 20 times no significant impairment of hydrophobic character has been noticed in case of fluorocarbon finishing agents as well as by the surface treated with C2H4 followed by C2F6 plasma (i.e., a two-step technique), wherein a complete loss of hydrophobic effect washing the silicone-treated materials for 10 times was observed. In breathability aspect, the plasma modification was found to be the best-suited technique with zero reduction of air permeability in comparison to wet-chemical finishing. The barrier test as a measure of dye absorption was conducted using protein solution, synthetic and human blood and the efficiency were verified by colorimetric technique. In contrast to pure plasma treatments, modification of the fabric with plasma in two-step treatment as well as with wet-finishing method using fluorocarbon compounds were completely impervious to artificial and real blood. The most striking feature was the zero uptake of the protein solution by all treated surfaces.

Made available in DSpace on 2016-06-02T20:00:17Z (GMT). No. of bitstreams: 1 DissSBSJ.pdf: 2619025 bytes, checksum: 6c40a2dff09cf162352a15e8a98340a0 (MD5) Previous issue date: 2006-07-31 / Financiadora de Estudos e Projetos / This work presents the results of a opinion poll, applied to the inhabitants of an urban area along the BR-050 highway, in Uberlândia MG, carried out to estimate the importance of the impacts originated by the Barrier Effect and its characterization attributes. The Barrier Effect refers to the motorized transportation infrastructure impacts over the non-motorized transport. The method applied to this survey to determine the importance degree of each variable and its attributes of characterization related to the Barrier effect consists of a questionnaire, elaborated according to the Likert recommendations, and with the utilization of the Successive Intervals Method to determine the distance of the elements of a scale. The method which has been considered appropriate and easy to apply, produced satisfactory elements to the proposed analysis. The results show that the highway, inserted in a urban site, limitate the on foot transport for the inhabitants of the surroundings of the highway (effects), resultants of the Barrier Effect. It also was possible to identify the importance of defining attributes of each limitation (causes). / Este trabalho apresenta os resultados de uma pesquisa de opinião, aplicada em pessoas residentes numa faixa da área urbana de Uberlândia MG ao longo da rodovia BR-050, realizada para determinar a importância dos impactos resultantes do Efeito Barreira e dos atributos de caracterização destes impactos. O Efeito Barreira refere-se aos efeitos das infra-estruturas de transporte sobre os deslocamentos realizados por modos não motorizados. O método empregado para determinar o grau de importância das variáveis de caracterização dos impactos resultantes do Efeito Barreira e dos atributos de definição destas variáveis consistiu na aplicação de um questionário, elaborado segundo as recomendações propostas por Likert e da utilização do Método dos intervalos sucessivos para determinar as distâncias entre os elementos de uma escala. Tal método apresentouse apropriado, de fácil aplicação e produziu elementos suficientes para a análise. Os resultados mostraram que existem restrições aos deslocamentos a pé realizados pelos moradores de uma área urbana seccionada por uma rodovia (os efeitos), resultantes do Efeito Barreira, como também permitiram identificar a importância dos atributos de definição destas restrições (as causas).

Highways, expressway and other infrastructure have a negative impact on the surrounding population of animals. These linear structures in the landscape create impassable barriers and thus cause more or less isolated subpopulations (called barrier effect). Therefore, the newly constructed building of European highways and passages specially built for the animals, known as green bridges (ecoduct). Effectiveness of transitions is influenced by several factors (width of the bridge, the frequency of passing cars, the speed limit, etc.). This thesis deals with the efficiency of artificial crossings for wildlife and provides an overview of the results published so far.