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  • 1.
    Andersson, Anders
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Bergman, Eva
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Piccolo, John
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Comparing mail-in, interview and tournament catch rates for a recreational salmonid fisheryManuscript (preprint) (Other academic)
  • 2.
    Andersson, Jan-Olov
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    A GIS-based landscape analysis of dissolved organic carbon in boreal headwater streams2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In boreal catchments, stream water chemistry is influenced and controlled by several landscape factors. The influence of spatially distributed variables is in turn dependent on the hydrological scale. Headwater streams have larger variability of water chemistry, and thus together represent a large biodiversity, and therefore need to be monitored in official environmental assessments. One objective of this study was, using Geographical Information Systems (GIS), to analyse co-variation between landscape variables and water chemistry and to determine which of the landscape variables have a major influence on the concentration of dissolved organic carbon (DOC) in headwater streams. Another objective was to find a simple method for predicting sources of DOC, using official map data and publically available GIS applications.

    Totally 85 headwater catchments (0.1-4 km2) in the county of Värmland, western south Sweden, were used in the study. Water chemistry was analysed for water sampled at low, medium and high flows, and landscape variables were extracted from official map data sources: topographic maps, a digital elevation model (DEM, 50 m grid), and vegetation data. Statistical analyses showed that topography (mean slope and mean topographic wetness index (TWI)) and wetland cover often correlated well with DOC in headwater catchments. Official map data could satisfactorily extract landscape variables (mean slope, mean TWI) that were useful in predicting stream water chemistry (DOC).

    A high-resolution elevation model, which was generated by interpolation of photogrammetric data, was used to calculate and evaluate two different wetness indices and their ability to predict the occurrence of wetlands in six catchments of different sizes and topography. The SAGA (System for Automated Geoscientific Analyses) wetness index (SWI) gave substantially better results than the TWI. The effects of resolution of DEMs on calculations of the SWI were investigated using 5, 10, 25 and 50 m grids. The results showed that SWI values increased with increasing cell size. The near linear increment of mean values for resolutions 10-50 m suggests a independence of terrain type and catchment size, which supported previous findings that indicated that mean slope and mean wetness index calculated from coarse elevation models may be used for prediction of DOC in headwater streams.

     

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  • 3.
    Andersson, Jan-Olov
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    DEM resolution effects on SAGA wetness index in boreal forested catchmentsManuscript (preprint) (Other academic)
  • 4.
    Andersson, Jan-Olov
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Nyberg, Lars
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Spatial variation of wetlands and flux of dissolved organic carbon in boreal headwater streams2008In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, no 22, p. 1965-1975Article in journal (Refereed)
    Abstract [en]

    In order to investigate the relation between water chemistry and functional landscape elements, spatial data sets of characteristics for 68 small (0·2–1·5 km2) boreal forest catchments in western central Sweden were analysed in a geographical information system (GIS). The geographic data used were extracted from official topographic maps. Water sampled four times at different flow situations was analysed chemically. This paper focuses on one phenomenon that has an important influence on headwater quality in boreal, coniferous forest streams: generation and export of dissolved organic carbon (DOC). It is known that wetland cover (bogs and fens) in the catchment is a major source of DOC. In this study, a comparison was made between a large number of headwater catchments with varying spatial locations and areas of wetlands. How this variation, together with a number of other spatial variables, influences the DOC flux in the streamwater was analysed by statistical methods. There were significant, but not strong, correlations between the total percentages of wetland area and DOC flux measured at a medium flow situation, but not at high flow. Neither were there any significant correlations between the percentage of wetland area connected to streams, nor the percentage of wetland area within a zone 50 m from the stream and the DOC flux. There were, however, correlations between catchment mean slope and the DOC flux in all but one flow situations. This study showed that, considering geographical data retrieved from official sources, the topography of a catchment better explains the variation in DOC flux than the percentage and locations of distinct wetland areas. This emphasizes the need for high-resolution elevation models accurate enough to reveal the sources of DOC found in headwater streams.

  • 5.
    Andersson, Jan-Olov
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Nyberg, Lars
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Using official map data on topography, wetlands and vegetation cover for prediction of stream water chemistry in boreal headwater catchments2009In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 13, p. 537-549Article in journal (Refereed)
  • 6.
    Andersson, Jan-Olov
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Nyberg, Lars
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Wetness indices as predictors of boreal wetlandsManuscript (preprint) (Other academic)
  • 7. Armstrong, Janet L.
    et al.
    Myers, Katherine W.
    Beauchamp, David A.
    Davis, Nancy D.
    Walker, Robert V.
    Boldt, Jennifer L.
    Piccolo, John
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Haldorson, Lewis J.
    Moss, Jamal H.
    Interannual and Spatial Feeding Patterns of Hatchery and Wild Juvenile Pink Salmon in the Gulf of Alaska in Years of Low and High Survival2008In: Transactions of the American Fisheries Society 2008; 137: 1299-1316Article in journal (Refereed)
    Abstract [en]

    To improve understanding of the mechanisms affecting growth and survival, we evaluated the summer diets and feeding patterns (prey composition, energy density, and stomach fullness) of hatchery and wild juvenile pink salmon Oncorhynchus gorbuscha in Prince William Sound (PWS) and the northern coastal Gulf of Alaska (CGOA). Our study (19992004) included 2 years of low (3%), mid (5%), and high (89%) survival of PWS hatchery pink salmon. Because variations in diet should affect growth and ultimately survival, we expected that the variations in diet, growth, and survival would be correlated. During August in the CGOA, pteropod-dominated diets and higher gut fullness corresponded to high survival (59%), and copepod-dominated diets and lower gut fullness corresponded to low survival (3%). Within years, no significant differences were found in diet composition or gut fullness between hatchery and wild fish or among the four PWS hatchery stocks. Diets varied by water mass (habitat) as juveniles moved from PWS to more saline habitats in the CGOA. In July, when juveniles were most abundant in PWS, their diets were dominated by pteropods and hyperiid amphipods. The diets of fish that moved to inner-shelf (i.e., the least-saline) habitat in the CGOA in July were dominated by larvaceans in low-survival years and pteropods in high-survival years. Diet quality was higher in CGOA habitats than in PWS in July. In August, fish moved to the more productive, more saline water masses in the CGOA, where large copepods and pteropods were dominant prey and diet quality was better than in PWS. Our results indicate that spatial variation in the diets of juvenile pink salmon in July and the timing of migration to the CGOA play a critical role in marine growth and survival

  • 8.
    Arndt, Andreas
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Long-term evaluation of management strategy of Laridae nesting-habitats in Lake Vänern, Sweden2024Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Anthropogenic activities at coastal areas are assessed to be a major threat to seabirds and associated with habitat degradation and loss, subsequently leading to population declines. After severe floods at the millennial shift a restriction of the water regulation of Lake Vänern, Sweden, with lower variations between high and low water levels was introduced, which has led to an increase of the vegetational cover in the lake’s islands, islets and skerries. Known as important seabird nesting-habitats, the vegetational increase on these islands has been assessed as a threat to the lake’s Laridae-populations and a cause to their negative population growth that has been noticed during the recent decades. Within LIFE Vänern 2014–2018 and an ongoing management strategy of nesting-habitats, 211 of 800 yearly bird-monitored nesting-locations were restored by clearing the locations from all brushwood, bushes and trees. I have evaluated the clearings with the expectation to see a positive long-term effect on the Laridae population growth at cleared compared to uncleared nesting-locations, and foremost on Laridae with a strong colonial nesting-behaviour and thus a strong dependency on open nesting-habitats. Against expectations, I found no difference in the Laridae-population growth at cleared compared to uncleared nesting-locations and thus no significant effects from the clearings on a larger scale, but when analysed by area and species, I found positive effects from the clearings in one of the nine management areas, as for one species (Common Gull) in one area. Moreover, the analysis of small cleared locations (<0.3 ha) revealed a negative correlation with all Laridae and in particular the black-headed gull, indicating that Laridae with a strong colonial nesting-behaviour responded negatively to the clearing of smaller nesting-locations. Turning a population decline of longevity species with low reproduction rates, such as Laridae, is difficult and might be one explanation for the fact that no major positive effects from the clearings could be detected after nine years of the management strategy (2015–2023). The results from the analysis of the clearings rather indicate that other factors might be more important for habitat-selection in the species studied. Moreover, my results show that the availability of nesting-locations might not be the most important factor limiting population growth, and that other factors such as the quality of foraging-habitat, predation or ground-substrate might be more important targets of conservation and population management efforts.

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  • 9.
    Arvidsson, Björn
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Flodpärlmussla - vad behöver vi göra för att rädda arten?2006Report (Refereed)
  • 10.
    Arvidsson, Björn
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Värmländsk nartur - värd att skydda och vårda2007Chapter in book (Refereed)
  • 11.
    Arvidsson, Björn
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Hultman, Jens
    Österling, Martin
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Öringtäthet och rekrytering hos flodpärlmussla2006Chapter in book (Other academic)
  • 12.
    Arvidsson, Björn
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Karlsson, Jens
    Flodpärlmusslan - skogsbäckarnas aristokrat2004Chapter in book (Refereed)
  • 13.
    Arvidsson, Björn
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Karlsson, Jens
    Recruitment in populations of freshwater pearl mussel (Margritifera margaritifera) in relation to population size and host density2004Conference paper (Refereed)
  • 14.
    Arvidsson, Björn
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Karlsson, Svante
    Mer värld i Värmland och mer Värmland i världen2007Chapter in book (Refereed)
  • 15.
    Arvidsson, Björn
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Karlsson, Svante
    Karlstad University, Faculty of Social and Life Sciences, Department of Geography and Tourism.
    Lönnbring, Gunilla
    Karlstad University, Faculty of Social and Life Sciences, Department of Social Studies.
    Stolare, Martin
    Karlstad University, Faculty of Social and Life Sciences, Department of Politics and History.
    Förändringar och kontinuitet i vardagslivets Värmland2008Report (Other academic)
    Abstract [sv]

    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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  • 16.
    Arvidsson, Björn L
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Karlsson, Jens
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Österling, Martin E
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Recruitment of the threatened mussel Margaritifera margaritifera in relation to mussel population size, mussel density and host density2012In: Aquatic conservation, ISSN 1052-7613, E-ISSN 1099-0755, Vol. 22, p. 526-532Article in journal (Refereed)
    Abstract [en]

    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.

  • 17.
    Backius, Helena
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Förändring av kärlväxters artsammansättning vid återupptagen hävd i skogligt avgränsade ängs- och hagmarker2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Old agricultural landscapes house a great biodiversity. To conserve this diversity the European Union award financial support in the form of environmental grants to encourage farmers to maintain pastures and hay meadows using old-fashioned methods. But are the measures effective and do they meet their purpose? The purpose of this study was to re-inventory ten sample plots from 2002 on the farm Brofallet to see how species composition of vascular plants had been affected by the nine seasons of using these old-fashioned methods management. The farm is completely surrounded by forest, isolated from other agricultural land. No significant overall change was observed concerning the composition of vascular plant species favored by traditional management. Qualitative observations, however, showed an increase in some species favored by traditional management. The conclusion is that the five-year commitment that farmers make to receive the environmental grants is not adequate enough to be able to detect changes in total diversity of vascular plants on a farm such as Brofallet, but that changes may occur faster at other levels in the ecosystem. Moreover, a ramification of this study is the idea that even environmental measures and documentation should be characterized by diversity. In summary, small-scale extensive farming may prove to be important in the overall quest for a sustainable society, both to exploit land for food production using extensive farming, and to maintain biodiversity at the landscape level.

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  • 18. Bergengren, Jakob
    et al.
    Olsson, Ivan
    Österling, Martin
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    The thick shelled river mussel (Unio crassus) brings LIFE+ back to rivers.2012Conference paper (Refereed)
  • 19. Berglund, O.
    et al.
    Larsson, P.
    Brönmark, C.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Eklöv, A.
    Okla, L.
    Factors influencing organochlorine uptake in age-0 brown trout (Salmo trutta) in lotic environments1997In: Can. J. Fish. Aquat. Sci. 54: 2767-2774Article in journal (Refereed)
  • 20.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Changes in abundance of two percids, Perca fluviatilis and Gymnocephalus cernuus along a productivity gradient: Relations to feeding strategies and competitive ability1991In: Can J Fish Aquat Sci 48:536-545Article in journal (Refereed)
  • 21.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Changes in nutrient load and lake water chemistry in Lake Ringsjön, southern Sweden, from 1966 to 19961999In: Hydrobiologia 404:9-18Article in journal (Refereed)
  • 22.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Conservations of landlocked populations of Atlantic salmon and brown trout2012Conference paper (Refereed)
  • 23.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Ecology of Atlantic Salmon and Brown Trout - Habitat as a Template for Life Histories2012In: Fish and Fisheries, ISSN 1467-2960, E-ISSN 1467-2979, Vol. 13, no 3, p. 360-360Article, book review (Other academic)
  • 24.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Effects of roach Rutilus rutilus on two percids, Perca fluviatilis and Gymnocephalus cernuus: importance of species interactions for diet shifts1990In: Oikos 57:241-249Article in journal (Refereed)
  • 25.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Foraging abilities and niche breadths of two percids, Perca fluviatilis and Gymnocephalus cernua, under different environmental conditions1988In: J Anim Ecol 57:443-453Article in journal (Refereed)
  • 26.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Influence of light and temperature on fish1984Report (Refereed)
  • 27.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Lax och öring i Klarälven2010Conference paper (Refereed)
  • 28.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Ringsjön i Skåne, restaurering genom cyprinidreduktion - effekten av fiskreduktionen1997Report (Refereed)
  • 29.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Salmon and trout in Lake Vänern - What can we do for the wild fish?2012Conference paper (Refereed)
    Abstract [en]

    Populations of migratorysalmon and trout have worldwide shown a decline due to human activities. Overthe years numerous measures have been undertaken to maintain these populations,and conservation of migratory salmonids requiresunderstanding of their ecology at multiple scales, combined with assessinganthropogenic impacts. Theregulated River Klarälven and Lake Vänern host endemic populations oflandlocked Atlantic salmon (Salmo salar) and brown trout (Salmo trutta). The historically high abundances of the salmonids in theRiver Klarälven in the early 1800s have decreased dramatically, reachingall-time lows after the completion of all nine Swedish hydroelectric powerstations in the 1960s. After an extensive stocking program and transportationof spawners past eight hydroelectric plants catches from commercial,maintenance and sport fishing have again increased. Recently, increases in theproportion of wild salmon returning to the River Klarälven have generated interestsin establishment of wild salmon inhabiting the entire River Klarälven, includingupstream of the Norwegian border. How well are we equipped to meet these newdreams, taking into account our limited knowledge of the species different lifestages, coordination between different actors involved in the conservationprocesses, and our skills to communicate and understand everybody’s role inthis conservation process?

  • 30.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Smolt, föda och vandring - sjövandrande lax och öring2007Conference paper (Refereed)
  • 31.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Temperature-dependent differences in foraging ability of two percids, Perca fluviatilis and Gymnocephalus cernuus1987In: Env Biol Fish 19:45-53Article in journal (Refereed)
  • 32.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Åtgärder i stora reglerade vattendrag2009Conference paper (Refereed)
  • 33.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Annadotter, H.
    Cronberg, G.
    Eriksson, M.
    Romare, P.
    Sjörestaurering genom cyprinidreduktion. Finjasjöns status under 1992 och 1993 samt effekter av mörtfiskreduktionen1994Report (Refereed)
  • 34.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Bergstrand, E.
    Lack of a top-down effect on the zooplankton community after a cyprinid reduction1999In: Hydrobiologia 404:77-87Article in journal (Refereed)
  • 35.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Bergstrand, G.
    Cronberg, G.
    Eriksson, M.
    Romare, P.
    Sjörestaurering genom cyprinidreduktion. Ringsjöns status under 19931994Report (Refereed)
  • 36.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Calles, Olle
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Lans, L
    Norrgård, Johnny
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Olsson, I
    Piccolo, John J
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Schmitz, M
    Vandrande fisk i Klarälven2008Conference paper (Refereed)
  • 37.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Cronberg, G.
    Eriksson, M.
    Hamrin, S.F.
    Linge, H.
    Romare, P.
    Ekosystemets struktur och infiltrationskapacitet i några infiltrationsdammar i Vombs vattenverk. Ekologiska undersökningar 19931994Report (Refereed)
  • 38.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Competition between a planktivore, a benthivore, and a species with ontogenetic niche shifts1994In: Ecology 75:1233-1245Article in journal (Refereed)
  • 39.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Gustafsson, Pär
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Gosselin, Marie-Pierre
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Forest-stream linkages: Effects of woody debris on brown trout (Salmo trutta)2009Conference paper (Refereed)
  • 40.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Norrgård, Johnny R
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Piccolo, John J
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Schmitz, Monika
    Uppsala universitet.
    Lax och öring i Klarälven - möjligheter för vild fisk och kvalité på utsatt fisk: Rapport av aktiviteter och uppnådda resultat under 2009-20102010Report (Other academic)
  • 41.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Piccolo, John
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Norrgård, Johnny
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Schmitz, Monika
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Lax och öring i Klarälven: möjligheter för vild fisk och kvalité på utsatt fisk2009Report (Other academic)
  • 42.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Hamrin, SF
    Romare, P.
    The effects of cyprinid reduction on the fish community1999In: Hydrobiologia 404:65-75Article in journal (Refereed)
  • 43.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Hansson, L-A
    Andersson, G.
    Biomanipulation in a theoretical and historical perspective1999In: Hydrobiologia 404:53-58Article in journal (Refereed)
  • 44.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Hansson,, L-A
    Persson, A
    Strand, J
    Romare, P
    Enell, M
    Graneli, W
    Svensson, J
    Hamrin, SF
    Cronberg, G
    Andersson, G
    Bergstrand, E
    Synthesis of theoretical and empirical experiences from nutrient and cyprinid reductions in Lake Ringsjön1999In: Hydrobiologia 404:145-156Article in journal (Refereed)
  • 45.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Nyberg, Lars
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Bladh, Gabriel
    Karlstad University, Faculty of Social and Life Sciences, Department of Geography and Tourism. Karlstad University, Faculty of Social and Life Sciences, Centre for the Studies of Social Sciences Didactics.
    Brandin, Elisabeth
    Laskerudsprojektet -helhetssyn på restaureringsarbete i skogslandskapet2005Report (Refereed)
  • 46.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Piccolo, John
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Raising brown trout (Salmo trutta) with less food - effects on smolt development and fin damage2013In: Aquaculture Research, ISSN 1355-557X, E-ISSN 1365-2109, Vol. 44, p. 1002-1006Article in journal (Refereed)
  • 47.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Piccolo, John
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Norrgård, Johnny
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Schmitz, Monika
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Landlocked migrating salmonids in large regulated systems2010Conference paper (Refereed)
  • 48.
    Björkman, Joachim
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Finns det bevis för täthetsberoende tillväxt eller överlevnad hos ettårig öring i Dammån och dess biflöden?2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study examined whether there is any evidence for density-dependent growth and survival of juvenile brown trout (Salmo trutta L.) in eleven nursery locals in the river Dammån-Storån and its tributaries Lekarån and Bastuån 1995-2010. Regression analyses were used to test for correlations between (i) density of 0+ and mean length of 1+ and (ii) density of 0+ and density of 1+. Thereafter three one-way ANOVAs were used to test for (i) any differences in mean length of underyearlings among these eleven locals during the same time period, (ii) differences in mean length between years and (iii) differences in maximum length of 0+ among locals.

    The results revealed weak negative correlations between density of 0+ and mean length of 1+,  and weak positive correlations between density of 0+- and 1+-brown trout. The analysis of variance on mean length of 0+ showed significant differences in mean length between the locals. The ANOVA on differences in mean length between years showed slight differences, and the ANOVA on differences in maximum length of 0+ showed significant differences. This study suggests that there is not strong evidence for density dependence in these populations, and that local conditions in time and space are important determinants of fish growth.

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  • 49.
    Blomqvist, Elin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013). Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Evaluation of two potential management strategies for garden lupin (Lupinus polyphyllus) in road verges2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Invasive plant species are a global problem that threaten native ecosystems. The garden lupin (Lupinus polyphyllus) is an invasive perennial herb and possesses several traits, which enables successful establishment and dispersal. Road verges serve as landscape corridors for exotic species, as well as being an important refuge habitat for many grassland species. To make conservation managements more efficient, an extensive knowledge of the target species and it’s traits is required. The aim of this study was to evaluate two potential management strategies for garden lupin in road verges. Mowing is an established strategy already, but to find out if different cutting intensities will affect biomass regrowth differently, one control group (no cut) and three harvest groups (1-3 cuts) were compared regarding leaf biomass, stem biomass, inflorescence biomass and total plant biomass. Another potential management strategy was evaluated focusing on the seed bank. Seeds of garden lupin were heat treated at 40 °C, 50 °C, and 70 °C and compared to control seeds (20 °C). Duration of treatments was 1, 5, and 15 minutes. Some seeds were watered before the heat treatment to break physical dormancy. Seeds of garden lupin were compared to three other species in the Fabaceae family: Trifolium incarnatum, Medicago sativa, and Lotus corniculatus. I found a significant effect of cutting frequency on regrowth of stem biomass, inflorescence biomass, and total plant biomass. Regarding leaf biomass, there was no difference between harvest groups. The fact that garden lupin plants primarily invest more resources in leaf biomass regrowth can be regarded as positive from a management point of view. However, biomass regrowth was depended on initial plant size, and the mowing response might differ between individual plants in populations. The water treatment did not break the physical dormancy of garden lupin seeds. Increased temperatures during heat treatments seemed to have an inhibiting effect on both seed germination and mean germination time. However, a high number of vital garden lupin seeds were remaining after the last observation. This might indicate that many seeds would remain vital if seed bank heat treatments were implemented as a management strategy. The strategy would probably be time consuming and expensive in relation to the desired reducing effect on vital garden lupin seeds. To develop resource efficient management actions on the species’ seed bank, more knowledge is needed. Mowing seems like a better management option if it is implemented at the right time twice a year. 

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  • 50. Boldt, Jennifer L.
    et al.
    Haldorson, Lewis J.
    Piccolo, John
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Armstrong, Jan
    Beauchamp, Dave
    Davis, Nancy
    Myers, Kate
    Walker, Trey
    Relationships of Growth, Condition and Feeding to the Survival of Juvenile Pink Salmon in the Coastal Gulf of Alaska2005Conference paper (Other (popular science, discussion, etc.))
1234567 1 - 50 of 521
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