| 1. |
- Arvidsson, Björn, 1952-, et al.
(författare)
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Förändringar och kontinuitet i vardagslivets Värmland
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den här studien ingår i Karlstads universitets och fakultetens för samhälls- och livsvetenskaper satsning på mångvetenskaplig forskning om "uthålliga livsmiljöer och komplexa nätverk". Målet med fakultetens satsning är att stimulera forskning och samverkan mellan offentliga och privata aktörer så att Karlstads universitet effektivt kan bidra till och bli en motor i det långsiktigt hållbara utvecklingsarbetet i regionen. Studien tar sin utgångspunkt i intervjuer med några värmländska familjer om hur vardagen gestaltar sig idag, hur det såg ut historiskt och hur det kan tänkas se ut i framtiden. Intervjuerna kommenteras av forskare från olika ämnesområden. I mötet mellan forskare från olika ämnen och forskningstraditioner uppstår nya sätt att problematisera det komplicerade växelspelet mellan olika sektorer av vår tillvaro. Problemen kan omformuleras, nya möten och kontakter vänder invanda tankegångar mot nya och innovativa riktningar och beredskapen att möta framtida utmaningar såväl för forskare som för regionala aktörer stärks och uppgraderas. Förhoppningen är att studien ska fungera som en plattform för den viktiga diskussionen kring uthållig regional utveckling för kvinnor, män, barn och gamla och stimulera innovationer och forskning som garanterar en framtid där utveckling och tillväxt balanseras mot uthållig miljö för människor och natur.
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| 2. |
- Arvidsson, Björn, 1952-, et al.
(författare)
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Flodpärlmussla - vad behöver vi göra för att rädda arten? : En workshop på Karlstads universitet
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Flodpärlmusslans situation i Sverige är bekymmersam, och i en stor del av de återstående populationerna sker ingen nyrekrytering av små musslor. För att belysa kunskapsläget om flodpärlmusslans situation och för att diskutera olika åtgärdsmöjligheter genomfördes i november 2005 en work shop vid Karlstads universitet med deltagande av naturvårdare från olika myndigheter och forskare. Vid mötet presenterades aktuell forskning i Skandinavien och olika uppföljningar som sker i olika myndigheters regi. Mötet bekostades av länsstyrelsen i Västernorrland, som fått ett nationellt ansvar att ta fram ett åtgärdsprogram för arten. I denna sammanställning redovisas en del av de föredrag och diskussioner som förekom vid mötet.
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| 3. |
- Arvidsson, Björn L, 1952-, et al.
(författare)
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Recruitment of the threatened mussel Margaritifera margaritifera in relation to mussel population size, mussel density and host density
- 2012
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Ingår i: Aquatic conservation. - Malden, MA : John Wiley & Sons. - 1052-7613 .- 1099-0755. ; 22, s. 526-532
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic, abiotic factors are considered main causes of recruitment failure of unionid mussels, including the freshwater pearl mussel (Margaritifera margaritifera). In this large-scale investigation, we instead examined the relationship between biotic factors and mussel recruitment.Juvenile mussel density was positively related to both mussel population size and density of which the last appeared to be a more accurate measure of recruitment.Host fish density of young-of-the-year and older brown trout (Salmo trutta) were positively related to recruitment. Moreover, the mean density of both age classes of fish, when grouped into density classes was positively related to juvenile mussel density, an effect that decreased at trout densities above 10 trout 100 m-2.There was a higher relative importance of mussel population size and density than trout density to recruitment.To increase recruitment of juvenile mussels, managers may apply measures that increase mussel density, and trout density up to about 10 trout 100 m-2 in connection to mussel beds. Mussel beds may also be managed and one possible measure within small and sparse mussel populations may be to concentrate the remaining mussels to areas where trout density is high. Likewise, young-of-the-year trout may also be moved to areas of high mussel density, as young trout individuals are relatively resident during their first year. This may increase mussel larval infection rates and mussel recruitment.
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| 4. |
- Österling, Martin, 1970-, et al.
(författare)
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Demonstrating the practical impact of studies on biotic interactions and adaptation of a threatened unionoid mussel (Margaritifera margaritifera) to its host fish (Salmo trutta)
- 2020
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Ingår i: Aquatic conservation. - : John Wiley & Sons. - 1052-7613 .- 1099-0755. ; 30:9, s. 1803-1808
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Tidskriftsartikel (refereegranskat)abstract
- To understand the ecological factors behind the decline of functionally important threatened species with complex life cycles, many different life-cycle stages need to be investigated. The highly threatened unionoid freshwater mussels, with their complex life cycle, including a parasitic stage on host fish, often have a large influence on biodiversity and ecosystem functioning. The overall aim of the present article is to summarize and discuss the impact of two articles published inAquatic Conservation: Marine and Freshwater Ecosystems(AQC) on biotic interactions and adaptation of a threatened unionoid mussel (Margaritifera margaritifera) to its host fish (Salmo trutta). The twoAQCpublications described research on the influence of population size and density of mussels and host fish, and host-parasite interactions between mussels and their host fish, on the recruitment of juvenile mussels. The results from these publications filled gaps in knowledge and resulted in recommendations and incentives for conservation. The results and method development have been used in practical conservation work with threatened mussel species and have been implemented and cited in management handbooks. The outcome of the publications has been implemented in large conservation and restoration projects, and in several recent scientific publications. Specifically, the results from one publication showed that ecological parameters such as mussel and host fish density and population size influenced recruitment of the threatened freshwater pearl mussel. The results from the second publication showed that understanding host-parasite interactions is important for comparing the suitability of host fish strains, and that host fish strains differ in their suitability for mussel infestations. In combination, the articles show that integrating ecological parameters of threatened mussels and their host fish with host-parasite interaction experiments can be an important influence on conservation recommendations, adaptive management and national management programmes for threatened species.
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| 5. |
- Österling, Martin E, 1970-, et al.
(författare)
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Habitat degradation and the decline of the threatened mussel Margaritifera maragaritifera: influence of turbidity and sedimentation on mussel an its host
- 2010
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 47:4, s. 759-768
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Tidskriftsartikel (refereegranskat)abstract
- 1. Habitat degradation is a major reason for species extinctions. For parasite–host interactions, the decline of a parasite may not only be related to the parasite’s tolerance to habitat degradation but also indirectly through the host’s tolerance to the same disturbance.2. Our objective was to explore the cause of population declines of the freshwater pearl mussel Margaritifera margaritifera by relating the age distribution, density and growth of the mussels with turbidity, sedimentation rates and density of the mussel’s host, trout Salmo trutta, in 26 Swedish streams.3. An analysis of the age structure of nine mussel populations showed that maximum age differed by 60 years, with five populations having low proportions of juvenile mussels. Adult mussel density was higher at sites where juvenile mussels occurred than at sites lacking juvenile mussels.4. Growth of adult mussels during the past 10 years was lower in the five streams lacking recent recruitment than in the four streams with recent recruitment, indicating that some environmental factor may be negatively impacting these populations.5. A comparison among 24 populations indicated that turbidity and sedimentation may be responsible for recruitment failure in 58% of the populations. The age of the youngest mussel was positively related to turbidity and sedimentation, and juvenile mussel density was negatively related to turbidity and sedimentation. In contrast, trout density was not related to recruitment of mussels or sedimentation, but was positively related to turbidity in all streams, both with and without recent mussel recruitment.6. Synthesis and applications. Recruitment failure of M. margaritifera appears to be related to its own vulnerability to turbidity and sedimentation rather than to its host’s response to this type of habitat degradation. The results from our study suggest that managers might be able to evaluate the potential viability of mussel populations by measuring stream turbidity. Restoration activities to improve the mussels’ environment should focus on reducing fine material transport into streams.
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| 6. |
- Österling, Martin, 1970-, et al.
(författare)
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Relationship of biotic and abiotic factors to recruitment patterns in Margaritifera margaritifera
- 2008
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Ingår i: Biological Conservation. - : Elsevier. - 0006-3207 .- 1873-2917. ; 141:5, s. 1365-1370
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Tidskriftsartikel (refereegranskat)abstract
- We investigated relationships of biotic and abiotic factors to recruitment patterns of the endangered freshwater pearl mussel (Margaritifera margaritifera) in 10 Swedish streams. We found that the maximum proportion of gravid mussels did not differ between streams with and without recent recruitment. Moreover, the mean glochidial load on trout (Salmo trutta), which was positively related to adult mussel density, did not differ significantly between these stream types. Thus, the larval stages of the freshwater pearl mussel were not related to recruitment failure. Instead, recruitment is probably hindered at the next stage in the life history of the mussels, the benthic stage, and may be related to sedimentation as turbidity was four times greater in streams lacking recent recruitment than in streams with recent recruitment. Furthermore, we found that juvenile mussel density was positively related to the number of glochidial infections per stream area in streams with ongoing recruitment, indicating that successful recruitment in these streams may depend on both mussel and trout density. Future research should thus examine biotic interactions between mussels and trout as well as the effects of sedimentation on benthic-living mussels.
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| 7. |
- Österling, Martin, 1970-, et al.
(författare)
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The genetic diversity and differentiation of mussels with complex life cycles and relations to host fish migratory traits and densities
- 2020
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Ingår i: Scientific reports. - : Nature Publishing Group. - 2045-2322. ; 10:1, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Many landscape and biotic processes shape the genetic structure of populations. The genetic structure of species with parasitic stages may also depend on the life history and ecology of their host. We investigated population genetic structure of the mussel Margaritifera margaritifera in Southern Sweden, and in relation to the population size and life history of its hosts, Salmo trutta and S. salar. Mussel populations were genetically differentiated into two clusters, further subdivided into four clusters and distinct conservation units. Regardless of host species, the genetic differentiation was lower among mussel populations sustained by sea-migrating than by resident hosts, while the genetic diversity was higher in mussel populations sustained by sea-migrating than by resident hosts. Genetic diversity of mussel populations was positively related to host abundance. Mussel population size was positively related to high genetic diversity of mussels sustained by resident hosts, while low mussel population size sustained by sea-migrating hosts had a high genetic diversity. The results of our study suggest a combined influence of mussels and host fish on genetic structure of unionoid mussels. We suggest to conserve not only mussel population sizes and host fish species, but also consider host migratory/resident behaviour and abundance when designing conservation programs.
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