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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.
1

Strengthening Ecological Connectivity : An exploratory study on establishing ecologicalcorridors in Frösön, Sweden

Rhode, Sarah January 2022 (has links)
The growing demand for urban areas has been a driving force for extensive changes to landscape. Thisrequires more focus on finding a balance between promoting urban development, and conservingbiodiversity in urban areas. The Intergovernmental Science-Policy Platform on Biodiversity andEcosystem Services (“IPBES”) suggests encouraging sustainable urban planning, as well as“maintaining, and designing for, ecological connectivity in urban spaces”. Ecological connectivity canbe modelled based on circuit theory. Landscape can be depicted as a conductive surface and resistancecan be attributed to landscape types according to its permeability to the movement of a species.Frösön is a district in the growing municipality of Östersund, Sweden, where several developmentplans are intended. This study aimed to identify where structural ecological connectivity existed inFrösön. It also aimed to determine where connectivity was disturbed by urban development, andexplore the options available to strengthen connectivity through establishing new ecological corridors.Land cover data was analysed to identify the forest patches that were larger than 50 000m2, andresistance values were attributed per land cover type. Circuitscape was used to model the connectivitybetween the forest patches, revealing the connectivity across Frösön. The development plans wereassessed to determine where the developments overlapped existing corridors with high connectivityvalues between forest patches. New corridors (pathways connecting high connectivity valuesbetween forest patches) that could compensate for the impact by development plans on connectivityas well as strengthen connectivity throughout Frösön were proposed. The findings in this reportconcur with the IPBES that urban development can be sustainable while preserving biodiversity.Additionally, the inclusion of connectivity models in the environmental impact assessment (“EIA”)process for developments, enables proactive decision-making on the design and location ofdevelopments. Moreover, it encourages urban development and the preservation of landscapeconnectivity. This study will be valuable to environmentalists carrying out EIAs and specialists thatopine on environmental policy and/or legislation. / <p>2022-0604</p>
2

Ekologisk konnektivitet för orkidén brunkulla

Olsson, Sanna January 2021 (has links)
Jordens ekosystem och dess funktioner är och verkar på komplexa sätt, vilket människan är direkt ochindirekt beroende av för välfärd. På grund av mänsklig utveckling har förändrad markanvändningtryck undan ekosystem och begränsat dess möjligheter till funktion. Att implementera gröninfrastruktur är ett sätt att ge arter möjlighet att sprida sig mellan habitat och på så vis främjasekosystemens funktioner. Ekologisk konnektivitet är spridningsförmågan för liv mellan livsmiljöeroch grön infrastruktur är nödvändig för att det ska ske.Syftet med studien är att undersöka möjligheten till ekologisk konnektivitet för växten brunkulla inomett avgränsat område utifrån befintlig data, samt att utvärdera vilket kompletterande data som skullekunna ge en bättre bild av levnadssituationen och konnektivitet för orkidén.Studien är geografisk avgränsad till ett mindre område inom Storsjöbyggdens gräsvärdetrakt medLänsstyrelsen Jämtland Härlejdalens dokumentation över gräsvärdetrakter som utgångspunkt.Kartverktyget QGIS Desktop 3.10 with GRASS har använts i studien och data har hämtats frånJordbruksverket, Naturvårdsverket, Trafikverket, SMHI. Data som har använts är: nationellgräsmarksanalys, ängs- och betesmarksinventering, artrika väg- och järnvägsmiljöer, nationellmarktäckardata, vattenwebb, samt åtgärdsprogram för brunkulla.Resultatet visar att det finns en teoretisk möjligheten till ekologisk konnektivitet för växten brunkullainom det avgränsade området. Befintlig data kan även identifiera tänkbara habitat inom området. Dockbekräftar endast en datakälla att växten finns på en lokal inom det studerade området. För att få enbättre bild av levnadssituation och konnektivitet för orkidén inom området skulle kompletterande datasom: data med kalkrik-fosforfattig jordsammansätning inom området, data över var brunkulla blivitobserverad inom det utvalda området, fältbesök etc.Eftersom ett mindre område har valdes ut slumpmässigt för analys kan resultatet endast representeradet området. Eftersom brunkullas frö kan spridas med vind eller via vattendrag krävs att möjligahabitat ligger tätt och/eller att vatten flyter genom habitatet. En kartläggning av en arts möjlighet tillkonnektivitet ett kunskapasinsamlad som kan leda till stödjande åtgärder som i sin tur gynnarbiologisk mångfald långsiktigt. / The earth's ecosystems work in complex ways. The environment in the ecosystems together with lifecreate functions that humans are direct- and indirect dependent on. Due to human expansion throughdevelopment and change of land use, this has created pressure on the ecosystems and has limited itsability to function. Green infrastructure is a prerequisite for the ecosystems and their functions andcontributes to increased ecological connectivity. Through creating value areas and managing meadowandpastureland, knowledge is gained, and areas of high ecological value are being preserved. Actionprograms for endangered species and habitat is a way to save and preserve life that have decreased innumbers due to human activity. Actions like these are for preserving and benefit biodiversity. Thepurpose of the study is to investigate the possibility of ecological connectivity for Gymnadenia nigrawithin a defined area. The study is based on collected data, and an evaluate which supplementary datacould provide a better picture of the living situation and connectivity for the orchid.The study is geographically limited to a smaller area in Storsjöbyggden grassland values areas with thecounty administrative board of Jämtland Härlejdalen documentations of grassland values areas as astarting point. The mapping tool: QGIS Desktop 3.10 with GRASS has been used and data has beenretrieved from the Swedish National Board of Agriculture, The Swedish Environmental ProtectionAgency, The Swedish Transport Administration and The Swedish Meteorological and HydrologicalInstitute. Data that have been used is national grassland analysis, meadow- and pasture inventory, richroad and rail environments, national ground cover data, action program for endangered species etc.The results show that there is a theoretical possibility of ecological connectivity for the plantGymnadenia nigra within the demarcated area. Existing data can also identify possible habitats withinthe area. However, only one data source confirms that the plant is located at a local within the studiedarea. In order to get a better understanding of the living situation and connectivity of the orchid in theaera, additional data such as: data with lime-rich-phosphorus-poor soil density, data on whereGymnadenia nigra has been observed in the selected area, a field study, etc.Because a smaller area has been randomly selected for analysis, the result can only represent that area.If another area had been selected, the outcome would probably have been different. In order to get abetter picture, additional data would be needed, such as soil data for calcareous, phosphorus-poor soilas well as a field research to find possible habitat on site. Since the seeds of Gymnadenia nigra can bespread by wind or via watercourses, it is required that possible habitats are dense and / or that waterflows through the habitat. / <p>2021-11-26</p>
3

Ecological connectivity, adult animal movement, and climate change: implications for marine protected area design when data are limited

Friesen, Sarah K 15 July 2019 (has links)
Marine protected areas (MPAs) are important conservation tools that can support the resilience of marine ecosystems. Many countries, including Canada, have committed to protecting at least 10% of their marine areas under the Convention on Biological Diversity’s Aichi Target 11, which includes connectivity as a key aspect. Connectivity, the movement of individuals among habitats, can enhance population stability and resilience within and among MPAs. This thesis aimed to understand regional spatial patterns of marine ecological connectivity, specifically through the mechanism of adult movement, and how these patterns may be affected by climate change. I used the Northern Shelf Bioregion in British Columbia, Canada, as a case study for four objectives: (1) evaluate potential connectivity via adult movement for the entire bioregion, using habitat proxies for distinct ecological communities; (2) assess potential connectivity via adult movement among existing and potential MPAs, using the same habitat proxies; (3) model potential connectivity via adult movement among marine protected areas for two focal species (Metacarcinus magister and Sebastolobus alascanus) and predict how this interconnectedness may shift based on projected ocean temperature changes; and (4) contribute the results of these analyses to the MPA technical team’s ongoing planning process so that connectivity may be considered in the implementation of a new MPA network in the bioregion. This thesis developed an approach to assess and design MPA networks that maximize inferred connectivity within habitat types for adult movement when ecological data are limited. It applied least-cost theory and circuit theory to model MPA suitability and interconnectedness, finding that these are projected to decrease for Sebastolobus alascanus but increase for Metacarcinus magister. I showcased some methods that may be used in MPA design and evaluation, with lessons for other contexts. Importantly, this thesis informed an ongoing MPA planning process, enabling ecological connectivity to be considered in the establishment of a new MPA network in the bioregion. Overall, this work provided examples for incorporating connectivity and climate change into MPA design, highlighting what is possible even when data are limited. / Graduate
4

Réseaux écologiques en régions alpines : une approche comparée de la mise en oeuvre d'un principe d'aménagement par la préservation. / Ecological networks in alpine regions : a comparative approach of the implementation of a spatial planning principle through nature protection

Kohler, Yann 04 February 2011 (has links)
Le concept de « réseau écologique » souligne l'importance de la connectivité écologique entre différents espaces naturels. Produit des évolutions historiques des pratiques de conservation et des nouvelles découvertes scientifiques, ce concept propose une nouvelle manière d'appréhender la protection de la nature. De nombreuses initiatives de « réseaux écologiques » ont ainsi lieu à travers le monde, notamment dans les Alpes. Elles témoignent de cette nouvelle conception de la protection de la nature, qui dépasse la simple conservation d'espèces pour s'orienter vers la préservation de systèmes écologiques. L'application de ce concept est étudiée dans trois régions alpines en Allemagne, Suisse et France. Sur ces territoires, de nombreuses initiatives différentes viennent se superposer, engendrant des questionnements quant à la coordination et la coopération entre ces divers échelles, acteurs, actions et les objectifs qui en découlent. En plus de ses impacts purement écologiques, la démarche de réalisation de réseaux écologiques semble également offrir un potentiel particulier allant au-delà des objectifs liés à la protection de la nature. Ce sont également ces autres effets fortuits qui sont au cœur de la recherche : le potentiel mobilisateur de l'outil offrant des possibilités particulières de gouvernance territoriale, les liens existants et potentiels avec l'aménagement du territoire, et les nouvelles logiques d'acteurs. Le concept de réseaux écologiques est venu bouleverser les pratiques de protection de la nature entrainant des modifications de la perception de la nature par la société et transformant ainsi également la relation entre la société et la nature. / The concept of “ecological networks” emphasises the importance of ecological connectivity between different natural areas. As a result of the historical evolutions of nature conservation practices and new scientific evidence this concept provides a new approach to nature protection. Numerous initiatives of “ecological networks” exist worldwide and also in the Alps. They are evidence of this new conception of nature protection going beyond the conservation of single species aiming the protection of functioning ecosystems. The implementation of this concept is analysed in three alpine regions in Germany, Switzerland and France. In these regions various different initiatives are overlapping one another generating interrogations concerning the coordination and cooperation between the different scales, actors, actions and related aims. In addition to the pure ecological impacts the creation of ecological networks seems to offer a particular potential going beyond the general objectives related to nature protection. These additional casual effects are in the centre of this research: the potential of the tool to mobilise various categories of different actors, the particular possibilities of regional governance, the prospective and existing links with spatial planning. The concept of ecological networks has completely changed nature protection practice inducing modifications of the perception of nature by society and therefore of the relation between society and nature.
5

Ekosystemtjänster &amp; grönstrukturplanering : Att synliggöra ekosystemtjänsternas nytta och värde i den kommunala planeringen med hjälp av ArcGIS-verktyget Matrixgreen / Ecosystem services &amp; green structure planning : To make the benefits and values of ecosystem services visible in municipal planning using the ArcGIS-tool Matrixgreen

Boklund, Ingrid January 2015 (has links)
Ekosystemtjänster är ekosystemens direkta och indirekta bidrag till människors välbefinnande. Ren luft, rent vatten, pollinering och biologisk mångfald är exempel på tjänster som människan är beroende av och vars värde behöver integreras i beslutsprocesser i samhällets alla olika sektioner. Kommunerna har en viktig roll i detta då de genom den fysiska planeringen har möjlighet att på lokal nivå styra utvecklingen mot mer långsiktigt hållbara lösningar. Syftet med examensarbetet var att synliggöra ekosystemtjänsterna i Knivsta kommuns grönstrukturplan och att med hjälp av ArcGIS-verktyget Matrixgreen analysera den ekologiska konnektivteten mellan de ekologiska strukturerna. En litteraturstudie lade grunden för arbetet och följdes av en workshop där viktiga ekosystemtjänster för Knivsta kommun identifierades. Utifrån den inlästa kunskapsbasen skapades ekologiska profiler där 11 av de 18 prioriterade ekosystemtjänsterna kunde kopplas till en viss biotoptyp. Biotoptypen kunde i sin tur kopplas till en biologisk art eller artgrupp, kallad profilart, med den specifika biotopen som möjlig livsmiljö. Profilartens habitatpreferenser (storlekskrav och spridningsmöjligheter) satte ramarna för hur konnektiviteten för respektive biotop skulle analyseras. Efter insamling av relevant kartunderlag skapades ekologiska nätverk i Matrixgreen. Nätverken analyserades med avseende på patchernas position i nätverket (”Betweenness Centrality”-analys) samt den totala konnektiviteten i kommunen (Komponentanalys). Gemensamt för de fyra valda biotoperna (våtmark, gräsmark, äldre barrskog och lövskog) är att de indirekt förser oss med de prioriterade stödjande ekosystemtjänsterna livsmiljöer och biologisk mångfald. De prioriterade ekosystemtjänsterna vattenrening, flödesreglering och översvämningsskydd kunde kopplas till biotopen våtmarker och material (dekorativa) och pollinering kunde kopplas till biotopen gräsmark. Till biotoperna barrskog och lövskog kunde de prioriterade ekosystemtjänsterna livsmedel (tama och vilda djur, växter), material (biomassa), bioenergi och klimatreglering kopplas. Nätverksanalyserna visar god konnektivitet i kommunen för våtmarker samt områden med äldre barrskog. För gräsmarker och lövskog är den totala konnektiviteten begränsad. Analyserna visar vidare att för respektive biotop finns ett antal områden som är extra viktiga för konnektiviteten, dessa områden har ett högt så kallat ”Betweenness Centrality”-värde. De ekologiska profiler som ligger till grund för analyserna är teoretiska profiler, inga platsbesök eller inventeringar har gjorts för att se hur verkligheten stämmer överens med teorin. De nätverk som har skapats och analyserats i detta examensarbete ska därför främst ses som en guide till var i kommunen de utvalda ekosystemtjänsterna finns. Nätverken utgör inte fullgoda livsmiljöer för de valda profilarterna och inga direkta slutsatser kan dras om var i kommunen en specifik art finns eller inte. Den biologiska mångfalden är en ekosystemtjänst i sig men utgör också en försäkring för ekosystemen som blir mer resilienta, det vill säga mer stabila och motståndskraftiga mot yttre störningar. Resilienta ekosystem är en förutsättning för de ekosystemtjänster som har studerats. Bristande konnektivitet i landskapet riskerar att leda till ökad fragmentering och en utarmad biologisk mångfald. / Ecosystem services are the direct and indirect contributions of ecosystems to human well-being. Clean air, clean water, pollination and biodiversity are all examples of ecosystem services that humans depend on and whose value needs to be integrated into decision-making processes in all different levels of society. Local authorities have an important role in this as they at local level through spatial planning have the possibility to steer development towards more sustainable solutions. The aim of this thesis is to make ecosystem services in Knivsta municipality visible through the green structure plan and to analyze the ecological connectivity between the ecological structures using the ArcGIS-tool Matrixgreen. A literature study laid the foundation for further work and was followed by a workshop where important ecosystem services to the municipality of Knivsta were identified. Ecological profiles were created where 11 of the 18 prioritized ecosystem services were associated with specific biotopes which in turn could be linked to a biological species or species groups, called target species, with the specific biotope as possible habitat. The habitat preferences of the target species (size requirements and distribution patterns) worked as a framework for how to analyze the connectivity for each biotope. This was followed by gathering of maps and the making of ecological networks in Matrixgreen. The networks were analyzed with respect to position of the patches in the network (Betweenness Centrality analysis) and the overall connectivity in the municipality (Component analysis). Common to the four selected biotopes (wetland, grassland, coniferous and deciduous forest) is that they indirectly provide us with the prioritized supporting ecosystem services habitats and biodiversity. The prioritized ecosystem services water treatment, flow regulation and flood control were linked to the biotope wetlands and materials (ornamental) and pollination were linked to the biotope grasslands. The biotopes coniferous and deciduous forest could be linked to the prioritized ecosystem services food (domestic and wild animals, wild plants), raw materials (fiber), bio-energy and climate control. The network analyses show good connectivity for wetland areas and coniferous forest in the municipality. The total connectivity for grasslands and deciduous forest is limited. The analyzes also show that for each biotope a couple of areas are especially important for the overall connectivity. These areas have a high Betweenness Centrality value. The ecological profiles upon which the analyzes are based are theoretical profiles, no site visits or surveys have been done to investigate how reality matches theory. The constructed and analyzed networks in this thesis are therefore to be seen mainly as a guide to where in the municipality the selected ecosystem services are available. The networks do not constitute adequate habitats for the selected target species and no conclusions can be drawn as to where in the municipality a specific species exists or not. Biodiversity is an ecosystem service itself but also represents an insurance for the ecosystem that becomes more resilient, i.e. more stable and resilient to external shocks. Resilient ecosystems are essential for the ecosystem services that have been studied. Lack of connectivity in the landscape could lead to increased fragmentation and eventually risk biodiversity depletion.
6

Distribution, Abundance and Movement of Fish among Seagrass and Mangrove Habitats in Biscayne Bay

Goebel, Patrick C 17 March 2016 (has links)
Inshore tropical and subtropical estuaries harbor a relatively high abundance and diversity of organisms. Specifically within estuaries, mangrove and seagrass habitats provide shelter and food for a plethora of organisms, through some or all their life histories. Given the biological connection between offshore coral reefs and coastal estuaries, there is a critical need to understand the underlying processes that determine distribution and abundance patterns within mangrove-seagrass habitats. The predatory fish assemblage within the mangrove and seagrass beds of Biscayne Bay, Florida (USA), was examined over 24-hr. time periods along a distance and habitat gradient from the mangrove edge and nearshore environment (0–300 m) to farshore (301–700 m) seagrass beds. This thesis also investigated the occurrence, distribution and timing of reef fish movement between offshore coral reef habitat and inshore seagrass beds over 24-hr periods. Results indicate that fish predators differed over both the sampling period and with distance from mangrove edge. The results also demonstrated reef fishes move into Biscayne Bay at dusk and exit at dawn by utilizing Broad Creek Channel as a passageway. This work supports the idea of diel migration of selected reef fishes to inshore seagrass beds and highlights the importance of connective channels between habitats. The results suggest that the degradation or loss of seagrass habitat could differentially impact the life-history stages of reef fish species.
7

Impacts écologiques des formes d'urbanisation : modélisations urbaines et paysagères / Ecological impacts of urban forms : urban and landscape modelling

Bourgeois, Marc 11 December 2015 (has links)
L’accélération du processus d’urbanisation, constatée à l’échelle mondiale depuis les dernières décennies, conduit à une artificialisation progressive des milieux naturels. La construction d’infrastructures de transport ou de nouveaux bâtiments fragmente les paysages de manière irréversible et cause une réduction des habitats écologiques et de leur connectivité. Le maintien de la fonctionnalité des réseaux écologiques, s’intègre désormais dans les politiques d’aménagement du territoire ou d’urbanisme soucieuses de la préservation de la biodiversité.En se focalisant plus particulièrement sur les évolutions urbaines à l’horizon 2030 dans l’Aire Urbaine de Besançon (développement résidentiel et variations de trafic routier), cette thèse cherche à évaluer l’impact potentiel des formes d’urbanisation sur la connectivité des réseaux écologiques des espèces animales. Ce travail de recherche privilégie l’approche par la modélisation en s’inscrivant à la fois dans le champ de la géographie théorique et quantitative et de l’écologie du paysage.L’application de cette démarche se fait en trois étapes : (1) simuler le développement résidentiel et ses évolutions de trafic associées à l’horizon 2030, à l’aide de cinq scénarios prospectifs présentant des formes urbaines différenciées ; (2) modéliser les réseaux écologiques de plusieurs espèces animales avec des graphes paysagers construits à partir de cartes d’occupation du sol et de données écologiques ; et (3) évaluer les impacts potentiels de chaque scénario sur les réseaux écologiques à partir de ces graphes à l’aide de métriques de connectivité, par mesure de la perte de connectivité imputable à chaque scénario de développement résidentiel.Les résultats obtenus montrent que les formes de villes denses et compactes, contrairement aux villes étalées, sont celles qui favorisent le mieux le maintien des connectivités écologiques pour la plupart des groupes d’espèces analysés. Des analyses plus approfondies mettent en avant la contribution importante des variations de trafic aux impacts écologiques de chaque scénario.D’après les analyses de sensibilité effectuées, le modèle utilisé est robuste, ce qui montre l’intérêt de la modélisation dans le processus d’aide à la décision pour la protection environnementale et la planification urbaine afin de penser la ville de demain de manière durable. / The global increase of urbanization during the past decades have induced a progressive artificialization of natural environments. The building of transport infrastructures and new housings causes a landscape fragmentation in an irreversible way and a strong decrease of the connectivity of ecological habitats. Maintaining the functionality of ecological networks is becoming a major goal of sustainable urban planning policies. With a special focus on urban evolutions in the horizon 2030 in the urban area of Besançon in eastern France (residential development and road traffic evolutions), this thesis aims to assess the potential impact of urban forms on landscape connectivity of animal species’ ecological networks. This research work promotes a modelling approach both on the field of theoretical and quantitative geography and landscape ecology.This approach follows three main steps: (1) simulating residential development and its associated road traffic changes using five prospective scenarios of differentiated urban forms; (2) modelling landscape graphs of various animal species using land-cover maps and ecological data; (3) assessing the potential impacts of each scenario on ecological networks from these graphs using connectivity metrics, with measures of the connectivity decrease attributable to each residential development scenario. Contrary to sprawled cities, the results show that compact and dense urban forms best promote the maintenance of ecological connectivity for the majority of species groups. Further analysis highlights the great contribution of road traffic evolutions regarding the ecological impacts of each scenario.According to some sensitivity analysis, the model used is quite robust. It demonstrates the interest of modelling in the decision-making process for environmental conservation and urban planning to think out the city of tomorrow in a sustainable way.

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