• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 13
  • 4
  • Tagged with
  • 17
  • 8
  • 7
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 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.
11

Klimatanpassning kring Vänern : om ansvar och problem med att minska risken för översvämningar / Climate adaptation around Vänern : about responsibility and problems with decreasing the risk of flooding

Larsson, Liisa January 2008 (has links)
Generellt går det att hantera klimatförändringar på två sätt. Dels genom att minska utsläppen av växthusgaser och dels genom att anpassa sig till de klimatförändringar som kommer. I denna uppsats kommer jag att fokusera på klimatanpassning. Ett av de områdena i Sverige som beräknas drabbas värst är runt Vänern, framförallt då sannolikheten för översvämningar väntas öka på grund av klimatförändringarna. Syftet är att ta reda på vilka problem det finns med att genom klimatanpassning minska risken vid översvämningar kring Vänern, samt undersöka vem som har ansvaret att lösa dessa problem. Metoden är en kvalitativ fallstudie med semi-strukturerade intervjuer som analyserats enligt ”grounded theory”. Även en mindre litteratundersökning har genomförts. Slutsatsen är att de övergripande problemen är att det finns en osäkerhet angående förutsättningen för klimatanpassning, att klimatanpassning är ett så nytt begrepp att det inte riktigt är implementerat i den politiska strukturen än, att det finns bristande medel för genomförandet samt att det finns en brist på samordning. Det övergripande ansvaret att minska sannolikheten för översvämningar ligger på staten. Det övergripande ansvaret att minska sårbarheten ligger till viss del på kommunerna, men är till stor del oklart. Något som skulle vara intressant att studera vidare är kopplingen i praktiken mellan klimatanpassning och hållbar utveckling. / In general there are two ways of coping with climate change. One way is through mitigation and the other is through climate adaptation. This essay will focus on climate adaptation. One of the areas in Sweden which is expected to be the most afflicted is around the lake Vänern, mainly because of the flooding risk which is expected to rise because of climate change. The purpose of this study is to find out what kind of problems there are with climate adaptation as a way of reducing flooding risk around the lake Vänern, and to find out who is responsible to solve these problems. The method used is a qualitative case study with semi-structured interviews. A miner literature study has also been made. The conclusion is that the general problems are insecurity about the background of climate adaptation, climate adaptation is a new concept which has not been implemented in the political structure yet, there is shortage of means for the implementation and there is a lack of coordination. The main responsibility of decreasing the probability of flooding is on the state. The main responsibility to reduce the vulnerability is partly on the county but for some part unclear. Something interesting to study further is the connection between climate adaptation and sustainable development.
12

Understanding of the value of the Ecosystem services for more sustainable water strategy : A case study of Water quality of the Lake Vänern in Kristinehamn Municipality

Kwizera, Prudence January 2011 (has links)
Natural resources management is one of the world‟s greatest concerns. It is a difficult task due to its complex nature. Natural resources are limited and scarce. Unfortunately and worst of all, they are under pressure, and stress due to unprecedented increase in their demand and inefficient use. But it is still possible to tackle this complex problem. This study focuses on understanding the value of the ecosystem services that human well-being depend on, as for more sustainable environment strategy on aquatic ecosystems management, such as lakes and rivers. Changing behavior and attitude can be a crucial complement and likely can stimulate our conscious effort towards saving our ecosystems beyond money contribution. This way of thinking seems to be overlooked and most people think that the development of technology and advancement in knowledge alone can provide solution. One way to overcome the problem of pressure and stressing of the environment is to develop adequate strategy and environmental policy. This policy should include economics measures where, when necessary and feasible. Since there are "no one solution and no one answer" to achieve the desired outcome of a sustainable future, it becomes necessary to adopt a multidisciplinary approach to environmental management and the understanding of the value and dynamism change of the ecosystem services. Adoption of efficient management is not enough; we have to adjust our attitude as well. To discuss this issue, the aquatic ecosystem, which the lake Vänern in Kristinehamn Municipality served as a case study.
13

Spelet om vindkraftverken : En komparativ analys av översiktsplanering för vindkraft i två kommuner vid Vänern

Andersson, Mattias January 2012 (has links)
The aim of the thesis is to study municipal planning for wind power in two Swedish municipalities, Karlstad and Säffle. The planning process is divided into three phases which are examined. The thesis discusses aspects of power and democracy of the cases as well as citizen participation and local issues concerning wind power at Lake Vänern. These are the research questions: - How is the wind power policy framed in the three phases of the planning process? - Which are the influence factors of the wind power policy in the three phases and what degree of influence have each of the influence factors? - Which values are most influential in the planning process and which groups of actors express them              - in the beginning of the planning process?              - in the termination of the planning process? - How is the democratic legitimacy of the planning process, in terms of the models ´liberal democracy´ and ´participatory democracy´? - What are the conditions of planning for wind power at Lake Vänern              - by the coast?              - in the open water area? Influential factors of the first phase of the process are the national wind survey, applications from wind power enterprises as well as a political will and consensus. In the second and third phases factors within the local administration management as well as the regional administrative board and a neighbouring municipality, are of importance in the municipality of Karlstad. In the municipality of Säffle citizen participation from a local opinion is of importance. The thesis discusses also the influence of the national energy authority, which has defined some areas as ´national interests of wind power’. These areas may be influential when supporting the municipal wind power policy. But in the termination of the planning process both municipalities make decisions which are not in favour of wind power in these areas. The planning process is democratic legitimate from a view of the model ´liberal democracy´ in the municipality of Karlstad and the model ´participatory democracy´ in the municipality of Säffle. In the municipality of Säffle values of preserving nature by the coasts are influential in the beginning of the process as well as a political will to promote wind power. The municipality is initially part of the same value group as the regional administrative board. In the termination of the process the municipality and a local opinion group express the same values in favour of social support among citizens and a lesser amount of new wind power areas. In the municipality of Karlstad values in favour of the wind power industry dominate in the beginning of the process. Later values of preserving an area of Lake Vänern from exploitation dominate. Initially the municipality is in the same value group as the wind power enterprises; in the later parts of the process the municipality is in the same value group as a neighbouring municipality with other opinions on wind power as well as the regional administrative board. In the termination of the process a new group of actors appears in Karlstad municipality. This group of actors wants to preserve a national heritage from nearby exploitation but is not successful. Local issues concerning wind power by Lake Vänern are finally also discussed. The coastal area has a strong protection for wind power; a protection that is weaker in the open water area. Remaining issues are about the interaction within the groups of actors.
14

Metodikstudie av trollingfisket i Vänern : Jämförelse av fångstrapportering mellan intervjuer och enkäter gjorda på trollingfiskare samt vädrets påverkan på ansträngning / A methodological study of angler surveys for the sport fishery in Lake Vänern: comparison between interviews and mail-in surveys for reporting catch

Höök, David January 2014 (has links)
There are five endemic populations of migratory Atlantic salmon (Salmo salar, Salmonidae) and brown trout (Salmo trutta, Salmonidae) remaining in Lake Vänern, whereof two are salmon and three are trout. There is one population of each species in Klarälven, also one of each in Gullspångsälven and there is a population of trout still remaining in Tidan River. Since the beginning of the 20th century endemic populations of salmon and trout have either vanished or declined dramatically due to the construction of hydropower in the rivers around the lake, and still today the future of the remaining populations remains uncertain. To manage salmonid fishes effectively more knowledge of their ecology throughout their different life-stages is needed. A large part of the Lake Vänern salmonoids lives are spent in the lake, where a mayor mortality factor is recreational fishing, especially angling. Estimation of fishing effort and catch is important in order to remain a sustainable fishery. In Lake Vänern commercial fishers are bound to report their catch, but anglers are not, -even though they are now thought to be responsible for the largest proportion of the catch. Angler interviews and access point surveys are the best ways to get accurate information in order to assess sport fish effort and catch. There are drawbacks of this method though that includes large costs, logistical problems and biased results due to the higher chance of interviewing the most avid anglers. To hand out mail-surveys is a kind of off-site survey that is less costly compare to interviews, but the drawbacks are bigger in getting correct information due to biased results from non-respondence. A study was conducted to compare an interview-survey with a mail-in survey, in which the interviews were conducted in Lillängshamnen, a port on the northern coast of Lake Vänern, and the mail-in surveys were distributed in different ports around the lake, though not in Lillängshamnen. This study shows a significant difference in catch per boat day between the interviews and mail-in survey. To find out more about how to develop the interview-survey there was also an analysis done on the correlation between weather and the number of interviews that were collected. One could find a negative correlation between numbers of interviews collected and the wind ratio, where very few interviews were collected once the wind speed measured more than 5-8 meters per second. There are improvements to be made both for the conduction of interviews and mail-in surveys, including more staff for conducting interviews at different ports and follow-ups on the non-respondents for the mail-in survey. / Av atlantlax (Salmo salar, Salmonidae) och öring (Salmo trutta, Salmonidae) finns idag fem endemiska populationer kvar i Vänern varav två är av lax och tre av öring. Det finns en klarälvsvariant av båda arterna, likaså finns det en gullspångsvariant av varje och sen finns även en öringpopulation kvar i Tidan. Sen början av 1900-talet har populationer av lax och öring utrotats eller minskat kraftigt till följd av vattenkraftens utbyggnad i vattendragen runt Vänern, och än idag är de resterande populationernas framtid oviss. För att kunna förvalta laxfiskarna på ett bra sätt krävs kunskaper om deras ekologi i dess olika livsstadier. En stor del av laxfiskarna runt Vänerns liv tillbringas i Vänern, där en mortalitetsfaktor består av fritidsfisket, då främst trolling. Uppskattning av ansträngning och fångst är viktigt för att hålla fisket i sjön på en hållbar nivå. Yrkesfisket måste rapportera all sin fångst men detta krävs inte av trollingfisket som idag tros stå för den största proportionen lax- och öringsfångst i Vänern. Genomförandet av intervjuer är en typ av plats- och åtkomstpunktsundersökning och är den bästa metoden att samla in korrekt information för att uppskatta sportfiskets ansträngning och fångst. Det finns dock nackdelar i form av stora kostnader, svår logistik och vinklade resultat då de mest entusiastiska fiskarna löper större chans att bli intervjuade. Att dela ut enkäter är en form av distansundersökning och även brevundersökning som kostar betydligt mindre än att genomföra intervjuer men brister vad gäller svarsfrekvens som i sin tur leder till vinklade resultat. En studie gjordes för att jämföra intervjuer med enkäter, där intervjuer genomfördes i Lillängshamnen på Vänerns norra kust och enkäter delades ut i olika hamnar runt hela Vänern, dock ej i Lillängshamnen. Denna undersökning visade att enkäter har en signifikant större fångst per båt än intervjuer. För att ta reda på mer om hur genomförandet av intervjuer skulle kunna förbättras undersöktes hur vädret påverkade antalet intervjuer som genomfördes. Man fick en negativ korrelation mellan antalet genomförda intervjuer och vindhastighet där ytterst få intervjuer genomfördes i vindhastigheter över 5-8 meter per sekund. Det finns förbättringspotential vad gäller både genomförandet av intervjuer och enkätundersökningar, bland annat mer personal till att kunna intervjua fler folk i olika hamnar och uppföljning på de enkäter som inte svarats på.
15

Väneramplitud – Lönsamhet? : Kvalitativ studie av åtgärder, genomförda för att reducera risker och kostnadspåföljder av en förändrad vattenregim / Väner lake amplitude – Profitable?

Linzie, Martin January 2013 (has links)
Tappningsstrategin för Vänern ändrades i ett beslut från Länsstyrelsen i Västra Götalands län och Vattenfall AB, på uppdrag av regeringen år 2008. Detta gjordes för att minska risken för översvämningar i Vänern.  Åtgärden var föreslagen av Klimat- och sårbarhetsutredningen, som försökt utreda konsekvenser av klimatförändringar för Vänern i ett framtida förändrat klimat. I utredningen används en metod för att mäta kostnader. Metoden är en kostnads-nytto-analys (Cost-Benefit-Analysis; CBA) som användes för att utvärdera bland annat Vänern med omnejd. Enligt denna uppsats saknas det värdering för naturmiljö och sociala faktorer i denna utredning. Denna uppsats försöker kommentara detta faktum. Det behövs andra, eller möjligtvis förändrade metoder för att kunna värdera naturmiljön. Uteblivna ekologiska och biologiska värderingar, får konsekvenser för helheten. Den förminskade vattenamplituden kommer att få konsekvenser som ej blivit värderade, den grund som beslut fattas på är då inkomplett vilket leder till att besluten också får konsekvenser som kan vara mycket kostsamma för samhället. Denna uppsats efterfrågar via intervjuer samt en litteraturstudie, vilka ekologiska värden som förväntas påverkas och vilka metoder som kan användas eller bör användas för att uppnå en helhetssyn. Det saknas idag tillräckliga data för att ge en konsekvensanalys av denna åtgärd. Därför borde man i enlighet med denna uppsats avvaktat med ny vattenregim i Vänern, tills alla fakta i målet finns att tillgå. / The water amplitude of the lake Vänern was lowered by a decision by the County Administrative board of Västra Götaland, this was carried out by the electric company Vattenfall AB in the year 2008. This was done to reduce the risks of severe flooding’s. The procedure was recommended by the report “Climate and vulnerability”. This will have adverse effects on the natural values around Vänern. The method used in the report was the Cost-Benefit-Analysis (CBA) method. In this valuation method, it is very difficult to value natural values according to their monetary value since the method itself lacks the procedures to do so properly. And also the investigators chose to not value these in a monetary sense because of the difficulties in doing so. This thesis questions through interviews and an extensive literature study why this came to pass, and how and why the natural values of the lake Vänern could have been valued. The possibility that the adverse effects on the natural values around the lake is diminishing is a fact not implemented in the report makes the proceeding decision to lower the water amplitude of Vänern, makes it difficult to determine the final consequences.
16

Catch and effort from a recreational trolling fishery in a large lake

Andersson, Anders January 2016 (has links)
Over recent decades recreational fisheries have grown substantially throughout the world. Despite this increase, catches from recreational fisheries have often been ignored in fisheries management, although this is now being remedied. Monitoring recreational fisheries can be expensive, and the primary means used for monitoring is angler (creel) surveys, typically funded from sales of fishing licences. The studies presented in this thesis examine different approaches to monitoring recreational trolling fisheries’ catch and effort, where fishing licenses are not required and there are no reporting requirements. I present results from a complemented roving/mail-in survey undertaken during 2013-2014 to estimate recreational effort and catch of Atlantic salmon (Salmo salar) and brown trout (S. trutta) in the largest lake in the European Union, Lake Vänern, Sweden. I also evaluate different angler catch reporting methods (mail-in, tournament reports and face-to-face interviews) and compare catch rates within and among spring and fall fishing periods. In addition, mail-in survey data are examined for recall bias.   I estimate that 28.7 tonnes of salmon and trout combined were harvested by the recreational trolling fishery in 2014, more than the commercial and subsistence fisheries combined. Seasonal differences in both recreational effort and catch were observed. Effort, in boat hours, was significantly higher in spring than in fall. Catch rates of trout were higher in fall than in spring, but there were no seasonal differences in catches of salmon. Harvest per boat day did not differ significantly among catch reporting methods, indicating that all three methods could be useful for managers interested in harvest rates. In contrast, total and released catch per boat day differed among reporting methods, with tournament anglers catching more fish in total. Finally, there was little evidence for recall bias in mail-in surveys, indicating that mail-in surveys are useful for collecting unbiased catch data. My study is the most comprehensive angler survey to date for Lake Vänern, and my results should be of immediate use to local fisheries managers and should also be of interest to researchers and managers interested in estimating catch and effort for fisheries at large spatial scales. / Over the past several decades recreational fisheries have grown substantially throughout the world. Until recently, however, recreational catch has been ignored in the management of many important fisheries. The studies presented in this thesis examine different approaches to monitoring recreational trolling fisheries’ catch and effort in Lake Vänern, Sweden, the largest lake in the European Union. Paper I presents results from a complemented roving/mail-in survey, designed to estimate recreational effort and catch of Atlantic salmon (Salmo salar) and brown trout (S. trutta). The results show that the recreational trolling fishery today harvests more salmon and trout annually than the commercial and subsistence fisheries combined, and that there are seasonal patterns in effort and catch. Paper II evaluates different angler catch reporting methods (mail-in, tournament reports, and face-to-face interviews), compares catch rates within and among spring and fall fishing periods and examines mail-in data for recall bias. Harvest per boat day did not differ significantly among catch reporting methods, indicating that all three could be useful for estimating harvest rates. However, tournament anglers had higher rates for released catch. Finally, there was little evidence for recall bias in mail-in surveys. In summary, this thesis has developed the framework for a recreational angler survey program for Lake Vänern, and should be of interest to researchers and managers interested in estimating catch and effort for fisheries at large spatial scales.
17

Sambandet mellan fetch och förekomst av stormusslor : En studie i Vänern / Relation between fetch and frequency of swedish freshwater mussels : A study in lake Vänern

Lawenius, Tove January 2018 (has links)
Sötvattensmusslor är viktiga i ekosystem där de finns, för människan utgör de även en ekosystemtjänst då de filtrerar vatten. De stora sötvattensmusslorna kallas stormusslor och finns i både sjöar och vattendrag i Sverige. I Vänern har fyra av de inhemska arterna noterats. Fetchen är längden på den öppna vattenytan från en punkt på land till närmsta land eller ö. Beroende på en strands storlek på fetch kan bottensedimentet se annorlunda ut. Musslorna är bottenlevande och spenderar mycket tid nedgrävda i bottensedimenten. När musslorna är uppe och filtrerar på bottenytan sitter de halvt nergrävda med bakänden uppåt. I denna rapport presenteras stormusslornas förekomst och dess relation till stränders fetch. Mer kunskap om stormusslorna behövs för att kunna utveckla ett mer anpassat naturvårdsarbete för dem. Inventering av musslor har skett på 20 olika platser i sydöstra Vänernområdet. Denna studie visar att en trend till ett samband finns mellan förekomst av stormusslor och lokalens fetch. Fetchen påverkar den maximala tätheten som musslorna kan uppnå. Analys ger statistisk signifikans på att tätheten minskar med ökad fetch. Tidigare forskning visar på liknande resultat. Emellertid tycks fler variabler vara beroende faktorer för hur mycket och om fetchen påverkar musslorna. / Freshwater bivalves are important organisms in the ecosystems they live, they also function as an ecosystem service for the human society. Swedish freshwater bivalves are divided into two groups; one with freshwater clams Sphaeriidae, and freshwater mussel with polyphile bivalves that are larger. Freshwater mussel lives in lakes and rivers, in Lake Vänern four species of the Swedish freshwater mussel have been observed. Fetch is the length of the open water from a point on shore to the nearest land or island. The structure of the lake bottom sediment can vary dependent on what value of fetch a shore has. In this report the freshwater mussel’s relation to the shore fetch is presented. More knowledge of the freshwater mussel is needed to develop a more suitable conservation work for them.    Inventory of mussel have been done on 20 different places in the southeast area of Lake Vänern. The results in this study shows a trend towards a relation between presence of freshwater mussel and shore fetch. Analysis on the highest density of mussel when the fetch data is divided in different classes shows a statistic significance for reduced density of mussel with increased fetch. Previous research shows similar results. However, more variables seem to be dependent factors for how and if fetch affect mussel.

Page generated in 0.0443 seconds