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Foraging-predator avoidance trade-offs made by migrant and resident elk (Cervus elaphus) on their sympatric winter rangeRobinson, Barry Glen Unknown Date
No description available.
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Foraging-predator avoidance trade-offs made by migrant and resident elk (Cervus elaphus) on their sympatric winter rangeRobinson, Barry Glen 11 1900 (has links)
Migratory behaviour of the Ya Ha Tinda (YHT) elk population is diminishing while the number of residents remaining on the YHT winter range year-round is increasing. Previous research addressing the fitness consequences of each migratory strategy assumed there was no advantage to either segment when they shared the YHT winter range. In testing this assumption, I found no spatial segregation of migrant and resident home-ranges during winter. Both groups were exposed to similar forage resources and residents were exposed to higher night-time, but not day-time predation risk. Residents were better than migrants at reducing the foraging costs of vigilance and increased vigilance in areas of high wolf predation risk, but not near human activity because of habituation. Migrants were not habituated to humans and exhibited more constant vigilance regardless of spatial variations in risk. My results do not support the previous assumption. Instead, I found residents may be at an advantage on the winter range while forage is abundant and no snow is present. / Ecology
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Articuler sécurité et performance : les décisions d'arbitrage dans le risque en aéronautique / Articulate safety and performance : risk trade-off decisions in aviationDi Cioccio, Alexandre 16 January 2012 (has links)
Cette recherche s’inscrit dans le domaine de la fiabilité des systèmes sociotechniques complexes, et vise à développer une nouvelle approche des arbitrages entre performance et sécurité : l’ingénierie de la résilience. La capacité des systèmes à risques à résister aux perturbations dépend, en dernière analyse, des acteurs de ces systèmes. Ceux-ci doivent réaliser des arbitrages entre des critères qui peuvent entrer en conflit : critères économiques immédiats (assurer la performance commerciale, par exemple), critères de sécurité (renoncer à satisfaire l’objectif immédiat de production). La thèse porte sur l’activité d’opérateurs d’une compagnie aérienne, en charge de répondre en temps réel à des appels d’équipages d’avions, qui signalent une complainte technique. Celle-ci peut-elle être traitée immédiatement : est-elle bénigne ou, au contraire, doit-elle conduire à l’annulation du vol concerné ? La thèse défendue est que, dans un système ultra sûr et ultra réglé, les conflits entre performance et sécurité se produisent lorsque la « sécurité gérée » rentre en conflit avec la « sécurité réglée ». Pour défendre cette thèse, trois études empiriques ont été mises en œuvre. Ainsi, plusieurs méthodes ont été utilisées en combinaison : l’observation et l’analyse de l’activité, la simulation d’activité, les questionnaires et les autoconfrontations.Les résultats obtenus ont permis, dans un premier temps, d’objectiver les arbitrages entre performance et sécurité, puis dans un second temps, d’identifier les critères qui président à ces arbitrages et d’expliciter les processus qui les sous-tendent. Ces résultats permettent, d’une part, de proposer des solutions acceptables telles que le retour d’expérience par la confrontation des pratiques, et d’assimiler la « sécurité gérée » comme un sous-ensemble de la « sécurité réglée », et d’autre part, de dépasser notre vision négative des violations, en les assimilant à une forme d’intelligence des opérateurs dans l’action. / This research is in the field of reliability of complex socio-technical systems and aims to develop a new approach to allow trade-offs between performance and safety: engineering resilience. The ability of systems to cope with disturbances ultimately depends on the operators of these systems. They must make trade-offs between criteria that may conflict: immediate economic criteria (i.e. to ensure business performance), safety criteria (i.e. give up to meet the immediate production objective). The thesis focuses on the activity of an airline’s operators, in charge of assistance via telephone for aircrew who report a technical complaint. It can be treated immediately; is it benign, or conversely should it lead to the cancellation of the flight?The thesis assumes that in an ultra-safe and ultra rule-based system, conflicts between safety and performance occur when the "rule-based safety" conflicts with "adaptative safety". To defend this thesis, three empirical studies have been implemented. Thus, several methods were used in combination: observation and activity analysis, simulation of activities, questionnaires and auto-confrontation.The results obtained allowed at first to objectify the trade-offs between performance and safety, then in a second instance to identify the criteria governing such trade-offs and explain the processes that underlie them.These results permit, on one hand, to propose acceptable solutions such as the feedback by comparing the practices and assimilate the “adaptative safety” as a subset of “rule-based safety”, and on the other hand to overcome our negative view of violations by treating them as a form of operators’ intelligence in action.
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Hållbarhet inom industriföretag : En kvalitativ studie om industriföretags strategiska hållbarhetsarbete / Sustainability within industrial companies : A qualitative study about industrial companies’ strategic sustainable actionEriksson, Fanny, Helene, Eriksson January 2018 (has links)
The Earth is facing many complex challenges. Social gaps between poverty and wealth are continuously growing, climate changes threaten the planet as well as its living creatures and the irresponsible human consumption goes on. Sachs (2015) mentions these issues as contribution to today’s existing unsustainable world and further argues that companies should take more responsibilities in the transformation process into a more sustainable world, where Herremans and Nazari (2016) identify industrial companies as the ones that should be the most responsible for sustainable actions. Furthermore, Lueg and Radlach (2016) argue that the usage of control mechanisms is a critical component of strategic sustainability actions. However, previous research has focused less on explaining how companies strategically work with sustainability, why this study aims at developing a deeper understanding of how industrial companies strategically take sustainable actions. Through ten qualitative semi-structured interviews within six industrial companies the study aims to achieve its purpose, with help of Elkington’s (1999) concept Triple Bottom Line (containing the dimensions profit, planet and people) and Malmi and Brown’s (2008) theoretical model of control mechanisms. The study shows that the strategic sustainable actions taken by industrial companies tend to differ depending on how long they have actively been working with sustainability. Initially the companies base their strategic sustainable actions on economic benefits and external pressure such as legislation and governmental verdicts, while companies who have been working longer with sustainable actions tend to voluntarily base their work on long-term visions of economic returns on sustainable investments. Further, the study shows that the control mechanisms culture and administrative functions tend to generate the most impact on sustainable actions. While the administrative functions expect to be more effective when implementing great changes in processes or routines, the culture tends to, due to its low abilities to change, be more helpful in the maintenance of sustainable behavior and values. / Planeten står inför många komplicerade utmaningar. Samhällsklyftan mellan rika och fattiga ökar, klimatförändringar hotar planetens och dess varelsers överlevnad och den mänskliga konsumtionen fortsätter att flöda. Sachs (2015) beskriver samtliga problem som bidrag till den ohållbara värld som idag existerar och menar vidare att företag kan spela en viktig roll i arbetet för en mer hållbar värld. Det torde enligt Herremans och Nazari (2016) vara industriföretag som i störst omfattning genom sin massproduktion bidrar till kritiska hållbarhetsproblem såsom global uppvärmning och människans överkonsumtion. Lueg och Radlach (2016) menar vidare att användning av styrfunktioner inom företag är en kritisk komponent i arbetet för en mer hållbar näringsverksamhet. Dock finns en avsaknad av tidigare studier som förklarar hur företag arbetar strategiskt med hållbarhetsfrågor. Genom den teoretiska ramen bestående av Elkingtons (1999) koncept Triple Bottom Line och Malmi och Browns (2008) modell för styrfunktioner samt empirisk insamling i form av tio kvalitativa semistrukturerade intervjuer, syftar studien till att skapa en förståelse för hur industriföretag arbetar strategiskt med hållbarhet. Studien visar att det strategiska hållbarhetsarbetet tenderar att skilja sig åt beroende på hur länge respondentföretagen arbetat aktivt med hållbarhetsaspekter. Initialt styrs företagens strategiska hållbarhetsarbete främst av ekonomiska fördelar samt extern påtryckning såsom lagstiftning och myndighetsbeslut, medan företag som arbetat längre tid med hållbarhet tenderar att frivilligt basera sitt hållbarhetsarbete mer på en framtidstro med visioner om långsiktig ekonomisk avkastning på hållbarhetsinvesteringar. Vidare visar studien att styrfunktionerna kultur respektive administrativa funktioner i olika syften tenderar att generera störst inverkan på hållbarhetsarbetet, varvid administrativa funktioner antas mer effektiva vid implementering av större förändringar i processer och rutiner. Kulturen antas å andra sidan, på grund av dess trögrörlighet, vara mer behjälplig i bevarandet av hållbara beteenden och värderingar.
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Effet maternels et compromis évolutifs chez une espèce à reproduction coopérative, le Républicain social (Philetairus socius) / Maternal investment and life history trade-offs in a cooperative breeding bird, the Sociable weaver, Philetairus sociusPaquet, Matthieu 18 December 2013 (has links)
Maximiser le nombre de copies de gènes transmises aux générations suivantes implique une série de compromis. Chez les espèces à reproduction coopérative, des individus ne se reproduisent pas mais participent aux soins des jeunes d'autres individus reproducteurs. Ces assistants sont particulièrement intéressants dans le contexte des traits d'histoire de vie car ils forment un environnement prédictible favorable pour la reproduction, et leur présence peut aussi influencer les compromis évolutifs chez les reproducteurs. Un compromis évolutif majeur mais sous-étudié dans le cadre de la reproduction coopérative est l'allocation maternelle notamment via des effets maternels qui sont des modifications épigénétiques du phénotype de la descendance. Nous avons étudié l'existence d'effets maternels associés à la présence d'assistants et leurs possibles conséquences sur les femelles et leurs descendants chez un oiseau colonial et coopératif du sud de l'Afrique, le Républicain social Philetairus socius. Nos résultats montrent que les femelles pondent des œufs plus légers en présence d'assistants et que ces œufs sont moins concentrés en corticostérone et testostérone. Nos résultats montent aussi une plus grande probabilité de survie pour les femelles se reproduisant en groupe pouvant être en partie due à leur plus faible investissement dans les œufs. De plus, l'étude de la température dans les nids en fonction de la taille des groupes a permis de suggérer d'autres bénéfices pour les parents et assistants, en particulier via une réduction des coûts de thermorégulation qui pourrait aussi permettre de garder de l'énergie pour la survie. Pour comprendre les conséquences de la présence d'assistants et de l'allocation différentielle pour les poussins, une expérience d'adoption croisée a été réalisée. Elle a révélé que les œufs pondus par les femelles avec plus d'assistants produisent des poussins qui quémandent moins, montrant que des effets maternels pourraient influencer le comportement des poussins. Enfin nous avons étudié la survie des poussins après l'envol à l'aide d'analyses de captures recaptures et avons trouvé de manière surprenante que les poussins à l'envol ont une probabilité de survie plus faible lorsqu'ils sont élevés présence d'assistants. Ces résultats dans leur ensemble démontrent l'importance d'étudier les effets maternels chez les espèces coopératives et ouvrent de nombreuses perspectives de recherche sur les conflits familiaux et de compromis évolutifs associés à la présence d'assistants. / Maximizing of the number copies of genes that are transmitted to the next generations involves a series of tradeoffs. In cooperatively breeding species some sexually mature individuals do not breed but instead help other individuals to raise their offspring. These helpers are particularly interesting in a life history context as they create a predictably favorable breeding environment and their presence can thus influence evolutionary trade-offs. A major evolutionary trade-off that is often neglected in studies on cooperative breeding is maternal allocation, notably through maternal effects that are epigenetic modifications of offspring phenotype. Here we investigate whether there are maternal effects induced by the presence of helpers and their possible consequences on females and their offspring in a colonial cooperative breeder of southern Africa, the sociable weaver Philetairus socius. Our results show that females lay smaller eggs in the presence of helpers and in addition these eggs have lower corticosterone and testosterone concentrations. Our results also show a higher survival probability of females breeding in groups, which may be partially due to their lower investment in eggs. In addition, a study of roosting chamber temperatures in relation to group size suggests further benefits for parents and helpers, particularly through lower costs of thermoregulation that could also allow energy savings for survival. To start understanding the consequences of helpers presence and differential maternal allocation for offspring we conducted a cross fostering experiment. Our results show that eggs produced by females breeding in larger groups produce chicks that beg at a lower rate, showing that maternal effects may influence chicks' behavior. Finally, we investigated post-fledging survival through capture-recapture analyses and, surprisingly, found that fledglings have a lower survival probability when raised with helpers. Taken together, these results demonstrate the importance of studying maternal effects on cooperative breeders and open several research prospects on family conflicts and life history trade-offs according to the presence of helpers.
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Water Chemistry Effects on Apple Snail (Pomacea paludosa, Say) Reproductive Patterns in the Northern EvergladesTrent, Tiffany Lorraine 01 April 2010 (has links)
Canals surrounding the Everglades carry enriched and polluted water high in minerals and nutrients. These enriched waters impact adjacent marsh habitats, altering flora and fauna species and abundance. Multiple studies have found gradients in nutrient levels as a function of distance from canals and emphasize the sensitivity of some organisms to these changes in water chemistry. Florida apple snails, Pomacea paludosa Say, are just one of many Everglades species sensitive to changes in water chemistry. They serve as an important staple in the diets of many Everglades predators including turtles, crayfish, limpkins and most importantly the endangered snail kite, Rostrahamus sociabilis which feeds almost exclusively on the apple snail. To examine potential effects of water chemistry on apple snail breeding patterns, we observed snail egg size, egg number per clutch, and carbon and nitrogen contents along water chemistry gradients and among snail breeding months at the Arthur R. Marshall Loxahatchee National Wildlife Refuge. Egg number per clutch and egg diameters were greatest in the most impacted zones and lowest in the pristine, interior zone. Carbon contents of eggs were highest in the interior and east side of the Refuge and lowest in the west side. Nitrogen contents of eggs were highest in the interior and west side of the Refuge, and lowest in the east side. Significant, albeit weak, positive trends were found between N content and egg diameter, C content and egg diameter, and between egg number per clutch and egg diameter, but only among specific zones and months. Results from this study suggest that snails in areas of the Refuge that are influenced by canal-water may produce greater numbers of apple snail offspring with greater egg diameters than those in less impacted areas. However, we do not know if this translates into higher hatchling success and survival.
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Ecosystem services in agricultural landscapes : A study on farming and farmers in South Africa and SwedenMalinga, Rebecka January 2016 (has links)
Humanity is facing challenges of sustainably producing enough food for a growing population without further eroding the world’s ecosystems. Transformation of natural habitats into agriculture has resulted in opportunities for civilization, but has also led to land degradation and loss of biodiversity, threatening the generation of ecosystem services. A better understanding of interlinkages and trade-offs among ecosystem services, and the spatial scales at which services are generated, used and interact, is needed in order to successfully inform land use policies. This includes the need to develop transdisciplinary tools that can disentangle the relationships between the supply of and demand for ecosystem services. This thesis investigates agricultural landscapes as complex social-ecological systems, and uses a multi-method approach to assess ecosystem service generation from different types of agricultural landscapes and to examine the social-ecological nature of these services. More specifically, the thesis discusses the importance of appropriate spatial scales, explores landscape change, integrates stakeholder knowledge and develops tools to investigate supply and demand of multiple ecosystem services. Paper I reviews the literature on ecosystem service mapping, revealing that services were mostly mapped at intermediate spatial scales (municipality and province), and rarely at local scales (farm/village). Although most of the reviewed studies used a resolution of 1 hectare or less, more case-specific local scale mapping is required to unravel the fine-scale dynamics of ecosystem service generation that are needed to inform landscape planning. To explore future uncertainties and identify relevant ecosystem services in a study area, paper II builds alternative scenarios using participatory scenario planning in the Upper Thukela region, South Africa. The paper compares methods to select services for an ecosystem service assessment showing that scenario planning added limited value for identifying ecosystem services, although it improved knowledge of the study area and availed useful discussions with stakeholders. Papers III and IV combines social and biophysical data to study the supply and demand of ecosystem services at farm- and landscape level, through participatory mapping and expert assessments in the Upper Thukela region, South Africa (paper III), and through in-depth interviews and biophysical surveys in Uppsala County, Sweden (paper IV), including small-scale and large-scale farmers. Both papers find apparent differences between the farmer groups in terms of the supply and the demand of services, and also the capacity of the farmers to influence the generation of services (paper III). Paper IV further establishes the importance of using multiple indicators combining social and biophysical data to quantify and investigate the complex social-ecological nature of ecosystem services. A cross-case comparison of ecosystem service bundles, using data from papers III and IV, finds similarities in bundles generated in the large-scale systems, while the small-scale agriculture bundles varied. This thesis provides new insights into the social-ecological generation of ecosystem services at fine scales such as farm and landscape levels, and shows the importance of including the knowledge of various stakeholders, combining different methods and tools to increase the understanding of supply and demand of ecosystem services. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.</p>
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Integrating gender and environment: synergies and tensions with a nexus approach : A case study of Stockholm municipalityÅsblom, Hanna January 2021 (has links)
The purpose of this study is to examine the integration of gender and environmental policies in Stockholm municipality. The study seeks to address the integration of these policy areas as itbuilds on previous research that have already established that the integration of the two can support the achievement of sustainable development. However, as tensions and synergies between these policies are not that well-explored, this study adds to literature by identifyingtensions and synergies in terms of policy integration between gender and environment. The study seeks to answer to what extent these policies are integrated, what challenges, tensions,and possibilities to find synergies there are. This is done through a single case study and content analysis. The study presents a merging of the two theories policy integration and ecofeminism, which is divided into five themes and numerous codes for the analysis. Five policy documents from the municipality and eight interview transcripts with civil servants is analysed. The study found that there are some aspects of integration between the two already, but to a limited extent. It identifies tensions between gender and environment as well as structural and organisational challenges for integrating these policy areas. Moreover, synergies were identified between these policy areas. Some interesting findings of the data was that it indicated success to integrate these policy areas in some parts of the policy-process, whereas there were limitations to integrate in other parts. Therefore, the study concludes that there needs to be ensuring mechanisms for the integration in the whole policy-process and to take advantage of the synergies that appears. Hence, this study suggests that for future research it would be interesting to investigate other aspects of the policy-process. The study also concludes that the results can be extended to other municipalities or local governments that are facing the same challenges to consider many aspects while working in silos.
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Changes in Life History within an Individual's LifetimeBillman, Eric J. 08 July 2011 (has links) (PDF)
A central goal of life history theory is to understand the selective factors that generate the diversity of reproductive patterns observed in nature. Within lifetime changes in reproductive investment will determine an organism's fitness; however, this area of life history theory has received less attention than comparisons among population that characterize life history traits as a single population mean. Reproductive allocation can be affected by multiple cues; the integration of these cues across an organism's lifetime generates the diversity in life history strategies observed in nature. Life history studies should examine the interacting effects of multiple cues on life history strategies to generate better predictions and generalizations of age-related changes in reproductive investment. An individual's life history strategy is inherently multivariate consisting of a coordinated suite of life history traits that, when combined across the organism's lifetime, determines its fitness. Life history strategies can therefore be described as a trajectory through multivariate space defined by life history traits. Here I describe life history trajectory analysis, a multivariate analytical approach for quantifying and comparing phenotypic change in life history strategies; this methodology is adapted from an analytical framework originally described for studies of morphological evolution. Life history trajectories have attributes (magnitude, direction, and shape) that can be quantified and statistically compared among taxa to determine if life history patterns are predictable. Using the life history trajectory analysis, I demonstrate the effect of prior experience on reproductive allocation in the burying beetle Nicrophorus orbicollis. The effect of prior experience resulted in a terminal investment or accentuated response to age-based cues, or resulted in a conservative investment strategy or reproductive restraint. In the livebearing fish Gambusia affinis, females adjust the level of reproductive investment to current reproduction based on age- or environment-based cues. Age-0 females decreased the level of reproductive investment to current reproduction in late summer prior to the onset of fall and winter months. Old females, on the other hand, increased the level of reproductive investment as the summer progressed. The reproductive restraint and terminal investment patterns exhibited by age-0 and age-1 females, respectively, were consistent with the predictions from the cost of reproduction hypothesis. These studies demonstrate how the life history trajectory analysis provides an analytical tool to test predictions of life history theory. Additionally, I provide evidence that organisms use multiple cues to determine the level of reproductive investment and that the strength of the effect of each cue will depend on the age of an individual.
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Bridging the regional scale and local contexts in the pursuit of sustainable interventions : Three cases along the Mapocho River in Santiago, ChileSaleh Selman, Andrea January 2019 (has links)
Alike many urban rivers, the Mapocho River in Santiago withstands enormous pressures from urban development. In the last decades there has been an increasing interest in the river, opening an opportunity to intervene its riparian areas where land is still available. But there is also the threat that future interventions will continue to be treated in isolation and respond to sectorial interests, hindering the river’s potential in the long run. With this in mind, the research aims to explore a way of understanding local contexts that takes into account both regional and local realities, providing a more holistic basis over which sustainable local interventions could take place in the future. Resilience theory is used as a conceptual framework to understand sustainability in its broad sense, aim at sustainability transformations through cross-scale interactions, and pay attention to the way in which social-ecological dimensions interact. Focusing on three local sites along the river, the analysis first explores priority ecosystem services from a regional perspective and then focuses on dimensions that become apparent at the local scale through site observations. This results in the proposition of a framework that explicitly links dimensions across scales by defining the way in which they interact to put forward what is possible and desirable in the current scenario. Within this interplay, the regional scale determines the influential capacity of the local site in question to alleviate regional sustainability challenges, while providing the relevance and urgency of specific ecosystem services to emerge. The local scale frames the spatial and socio-cultural feasibility to intervene the site, putting forward physical and value dimensions. The analysis of interactions highlights relevant linkages and conflicts that could inform and guide sustainable interventions at the local scale. Findings suggest that a specific ES can sometimes serve as a gateway to pursue synergicefforts between diverging interests, that physical dimensions like spatial delimitation and accessibility can play a key role, and that the consideration of value dimensions can help handle inevitable trade-offs. / Likt många andra urbana floder är Mapocho-floden i Santiago utsatt för omfattande påfrestningar till följd av en urban utveckling. Under de senaste decennierna har dock intresset för floden ökat, vilket har öppnat upp för nya möjligheter att kunna påverka flodens strandområden kring de platser där mark fortfarande finns tillgängligt. Trots detta kvarstår emellertid hotet om att framtida insatser ska fortsätta behandlas isolerat och svara på sektoriella intressen, vilket därmed skulle kunna inverka negativt på flodens potential på längre sikt. Med detta i åtanke syftar denna studie till att utforska sätt att förstå lokala sammanhang som tar hänsyn till både regionala och lokala verkligheter och som därmed kan bidra till en mer holistisk grund för hur lokalthållbara interventioner kan äga rum framöver. I studien används resiliensteorin som ett konceptuellt ramverk för att förstå hållbarhet i dessvida bemärkelse, syfta till hållbarhetsomvandlingar genom interaktiva interaktioner och uppmärksamma hur social-ekologiska dimensioner interagerar. (Hard to understand). I analysen har ett antal prioriterade ekosystemtjänster undersökts ur ett regionalt perspektiv för tre lokalaplatser längst floden och därefter har analyser utförts för de dimensioner som har kunnat identifierats på lokal skala genom platsobservationer. Resultatet av detta arbete har lett fram till ett ramverk tänkt att koppla samman dimensioner mellan skalor genom att definiera hur de interagerar och på så vis synliggöra vilka möjligheter som finns i de aktuellas cenarierna. Inom detta samspel är det den regionala skalan som avgör graden av påverkan de lokala platserna har i rollen att kunna motverka regionala hållbarhetsutmaningar, samtidigt som det blir möjligt att kartlägga specifika ekosystemtjänster som kan vara relevanta och av brådskande karaktär. Den lokala skalan ramar in de rumsliga och sociokulturella möjligheterna att kunna ingripa på platserna genom att lägga fram både fysiska och värdefulla dimensioner. Analysen av dessa interaktioner har således kunnat belysa relevanta kopplingar och konflikter som kan informera och vägleda beslutsfattare kring hur hållbara åtgärder kan genomföras på den lokala skalan. Studiens resultat visar även på att specifika ES ibland kan verka som en brygga för att bedriva synergiska kraftansträngningar mellan divergerande intressen, där fysiska dimensioner likt rumslig avgränsning och tillgänglighet kan spela nyckelroller samt där övervägning av diverse värdedimensioner kan bidra till att hantera oundvikliga trade-offs.
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