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  • 1.
    Adolfsson, Oscar
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Effekter av inkuberingstemperatur hos juvenil atlantlax (Salmo salar L.)2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Rising temperatures, because of climate change, will have major consequences for the world's fish populations, including the Atlantic salmon Salmo salar L. The greatest temperature changes are expected to occur during winter, which will affect S. salar since the eggs are developing during this time of year. Several studies have shown that elevated temperatures during embryogenesis cause morphological changes, in S. Salar, that are shown in later life stages. Some of these studies indicate that eggs incubated at high temperatures should generate parr with deeper bodies. To investigate whether high temperatures during the egg stage cause changes in body shape, parr from normal and high temperature incubated eggs, referred to as as “cold” and “warm” fish, respectively, were examined. A box-truss of euclidean distances between 10 landmarks on the fish body and a discriminant function analysis (DFA) was used to determine which of the distances best discriminated between the two groups. The test showed a significant discrimination between cold and warm parr regarding body shape where cold parr had greater heads and warm parr were deeper over the tail region and showed greater distances between the pelvic fin and the front attachment of the anal fin. 67,3 % of all parr where correctly classified by the test. These results support those notions that indicates that the incubation temperature is important for the morphological development of S. salar although it does not support the hypothesis.

  • 2. Affonso, Igor de Paiva
    et al.
    Karling, Leticia Cucolo
    Takemoto, Ricardo Massato
    Gomes, Luiz Carlos
    Nilsson, Per Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013). Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Light-induced eye-fluke behavior enhances parasite life cycle2017In: Frontiers in Ecology and the Environment, ISSN 1540-9295, E-ISSN 1540-9309, Vol. 15, no 6, p. 340-341Article in journal (Refereed)
  • 3.
    Andersson, Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Catch and effort from a recreational trolling fishery in a large lake2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    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.

  • 4. Andersson, Anders
    et al.
    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)
  • 5. Andersson, Anders
    et al.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Bergman, Eva
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Su, Zhenming
    Andersson, Magnus
    Piccolo, John
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Estimating effort and catch of a recreational trolling fishery in one of Europe’s largest lakesManuscript (preprint) (Other academic)
  • 6.
    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.

     

  • 7.
    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)
  • 8.
    Andersson, Lena
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Flodpärlmusslans (Margaritifera margaritifera) påverkan på öringens (Salmo trutta) tillväxt, konditionsfaktor och habitatval.2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The freshwater mussel family Unionoida lives a complex life with its host animals and the freshwater mussel family’s existence is threatened worldwide. One of these species, the pearl mussel (Margaritifera margaritifera), is a “responsibility species” for Scandinavia and a lot of work is ongoing to save the species. In Scandinavia there are still existing populations, but in many waters recruitment of juvenile mussels is completely lacking or insufficient. To support recruitment and also reintroduce the mussel into suitable watercourses, more knowledge about its complex life cycle and how it affects its host brown trout (Salmo trutta), is required. Attempts have been made to introduce gravid mussels or already infected trout in order to try to rejuvenate or to reintroduce mussels in some rivers. In this study, 293 trout individuals were captured from three watercourses in western Sweden with no or inadequate recruitment of juvenile pearl mussels. The brown trout were treated with mussel infection by being kept in containers with the presence of gravid mussels and compared to a control group where no mussels were present. Growth, condition factor and habitat selection were investigated and checked after treatment by scanning the trout with a mobile scanner and recaptured for control. The analyzes showed a significantly lower growth on those trout treated with mussel infection during the time they were stored in the containers. After a month in freedom in the streams, there was no differences in growth or condition factor. Habitat choice studies showed that trout with a higher degree of infection chose calmer water with a bottom layer of finer sediment. The study showed that this method could be a simple way of increasing the reproduction success of pearl mussel. The method requires relatively little work effort and small disturbance to host fish or the aquatic environment.

  • 9.
    Andersson, Sandra
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    The effects of artificial illumination on invertebrate drift2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 10.
    Bengtson, Johanna
    Karlstad University, Faculty of Social and Life Sciences.
    The relationship between behaviour and metabolic rate of juvenile Brown trout Salmo trutta2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In salmonids, the decision to migrate or remain resident is influenced by the status, and hence condition, of individuals. Status has been suggested to arise from the temperament of fish. In this study the links between standard metabolic rate and the levels of aggressiveness and shy/boldness were examined for 0+, hatchery-raised brown trout (Salmo trutta). I hypothesized, from the results of earlier studies (Cutts et al., 1998; Yamamoto et al., 1998), that high metabolic rates (MR) would be positively correlated to levels of aggression and boldness. The study was conducted in 200 L aquaria in which aggressiveness was measured by allowing each fish to interact with a mirror image of itself, and shy/boldness was tested by measuring the amount of time a fish used before exploring a new area. Standard metabolic rate was measured in a flow-through respirometer. In contrast to my expectations, there was no correlation between the different behavioural measures and the metabolic rate of fish. Also, no correlation between boldness and aggressiveness of fish was found. In additional testing aggressiveness correlated positively with the condition of fish (in coherence with Harwood et al., 2003) but, contrary to earlier studies (Överli et al., 2004; Schjolden & Winberg, 2007), not with the speed of acclimatization. The difference in results between this test and earlier studies, concerning the degree of correlation between MR and aggressiveness, suggests that the strength of this link differs between species of salmonids. Also, it may suggest changeability in the MR – behaviour link in different environments. Last, the status and condition of individuals cannot be unambiguously explained by temperament alone, but arise from a wider array of physiological and environmental factors.

     

  • 11.
    Bengtsson, Mikael
    Karlstad University, Division for Environmental Sciences.
    Utvärdering av omlöp vid Finsjö i Emån: Evaluation of natural fishways at Finsjö in the river Emån2009Student thesis
    Abstract [en]

    The purpose of this paper is to determine the extent to which trout used fishways to swim past two power plants at Finsjö in River Emån. Two different methods of  collecting data were used, radiotelemetry to determine if fish find the fishways (attraction efficiency) and PIT-tags to measure the number of fish that passed through the fishways (passage efficiency). The study showed that passageefficiency, being 89 % at lower Finsjö and 100 % at upper Finsjö, was high compared to other similar studies. Attraction efficiency was 75 % at lower Finsjö and 59 % at upper Finsjö, which indicates that the fish have difficulty finding the fishway entrances, particularly at upper Finsjö.

  • 12. 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)
  • 13.
    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)
  • 14.
    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?

  • 15.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Greenberg, Larry
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Norrgård, Johnny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Piccolo, John
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Schmitz, Monika
    Evolutionsbiologiskt centrum, Uppsala universitet.
    Lax och öring i Klarälven - möjligheter för vild fisk och kvalité på odlad fisk: Slutrapport 2008-20122013Report (Other academic)
    Abstract [sv]

    Data från 1800-talet visar att fångsterna av lax och öring i både älv och sjö varit mycket högre än idag. Storskaliga dämmen, kraftigt fiske i Dejeforsen, nio kraftverk i den svenska delen av Klarälvens huvudfåra, och användandet av älven för timmerflottning har bidragit till detta. Efter att utsättning av kompensationsodlad fisk startade ökade fångsten igen, även om den fortfarande är låg.

    Fältundersökningar av vild laxsmolt visade att 16 % av smolten klarade sig hela vägen förbi de åtta kraftverken mellan Edebäck och Forshaga. Under studien var vattenföringen, och därmed spillet, lågt, vilket troligen bidragit till de höga förlusterna. Normalt spills det inte under hela smoltvandringsperioden, vilket är olyckligt.

    Lax och öring uppfödda under normala odlingsförhållanden är oftast större och fetare än vild fisk. Vi födde upp lax med olika fodertyper och fodermängder. Mängden föda påverkade laxens tillväxt och smoltmognad, och lax som fått fettfattigt foder var mest ”naturlik”. Den klarade också vandringen bäst, 80 % tog sig till Vänern medan 55 % av laxen som fått normalt eller lite foder. Bara 20 % av tidigt könsmogna hanar tog sig till Vänern.

    Rapporten avslutas med implikationer och förslag till åtgärder och fortsatta studier.

  • 16.
    Bergman, Eva
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Norrgård, Johnny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Piccolo, John
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Gustafsson, Pär
    Nilsson, Fredrik
    Länstyrelsen i Västra Göralands län.
    Hart, Paul
    University of Leicester.
    Atlantic salmon and brown trout in Lake Vänern: A proposal for a co-management system2014In: Aquatic Ecosystem Health & Management, ISSN 1463-4988, E-ISSN 1539-4077, Vol. 17, no 4, p. 365-373Article in journal (Refereed)
    Abstract [en]

    Co-management is of increasing interest for fisheries management. We explore possibilities for, and barriers to, developing a co-management system, using threatened populations of landlocked Atlantic Salmon and Brown Trout as examples. Good management of natural resources requires not only knowledge about the resource but also suitable tools to collect information and make decisions. In large ecosystems this can be difficult because many actors are involved, and various societal borders and traditions become barriers. Vänern is the largest lake in the EU and it holds several distinct populations of large-bodied landlocked Atlantic Salmon and Brown Trout. The lake is used for commercial, subsistence, and sport fishing as well as for other recreational activities, and in Klarälven, the largest river entering Vänern, sport fishing is popular. These salmonid populations were at critically low levels during the 1960s, but a stocking program since then has maintained the fishery, and at least one wild stock appears to be recovering since being protected in 1993. Ecosystem users all have different needs: in the lake, sport fishermen say that catches of hatchery fish have declined, and commercial fishermen have focused on other species. In the river, wild salmon may be recovering: sport fishing is popular and an ongoing project investigates the possibilities for salmon to be able to circumvent hydro-electrical plants and reach historical Norwegian spawning areas. Not only do we lack information about the salmonids’ different life stages, we also lack a suitable socio-political organization to find sustainable solutions to the different needs of diverse user groups. We argue that a co-management system that enfranchises user groups in the Vänern-Klarälven ecosystem will improve sustainable management of wild and hatchery fish.

  • 17.
    Bienau, Miriam J.
    et al.
    Germany.
    Kröncke, Michael
    Germany.
    Eiserhardt, Wolfgang
    Norway.
    Otte, Annette
    Germany.
    Graae, Bente
    Norway.
    Hagen, Dagmar
    Norway.
    Milbau, Ann
    Umeå University.
    Durka, Walter
    Germany.
    Eckstein, Rolf Lutz
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Synchronous flowering despite differences in snowmelt timing among habitats of Empetrum hermaphroditum2015In: Acta Oecologica, ISSN 1146-609X, E-ISSN 1873-6238, Vol. 69, p. 129-136Article in journal (Refereed)
    Abstract [en]

    The topography within arctic-alpine landscapes is very heterogeneous, resulting in diverse snow distribution patterns, with different snowmelt timing in spring. This may influence the phenological development of arctic and alpine plant species and asynchronous flowering may promote adaptation of plants to their local environments.We studied how flowering phenology of the dominant dwarf shrub Empetrum hermaphroditum varied among three habitats (exposed ridges, sheltered depressions and birch forest) differing in winter snow depth and thus snowmelt timing in spring, and whether the observed patterns were consistent across three different study areas.Despite significant differences in snowmelt timing between habitats, full flowering of E. hermaphroditum was nearly synchronous between the habitats, and implies a high flowering overlap. Our data show that exposed ridges, which had a long lag phase between snowmelt and flowering, experienced different temperature and light conditions than the two late melting habitats between snowmelt and flowering.Our study demonstrates that small scale variation seems matter less to flowering of Empetrum than interannual differences in snowmelt timing.

  • 18.
    Bowes, R. E.
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Thorp, J. H.
    Consequences of employing amino acid vs. bulk-tissue, stable isotope analysis: a laboratory trophic position experiment2015In: Ecosphere, Vol. 6, no 1Article in journal (Refereed)
  • 19.
    Bowes, Rachel E.
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Lafferty, M. Holliday
    Thorp, James H.
    Less means more: nutrient stress leads to higher delta N-15 ratios in fish2014In: Freshwater Biology, Vol. 59, no 9, p. 1926-1931Article in journal (Refereed)
  • 20.
    Bowes, Rachel E.
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Thorp, James H.
    Reuman, Daniel C.
    Multidimensional metrics of niche space for use with diverse analytical techniques2017In: Scientific Reports, Vol. 7Article in journal (Refereed)
  • 21.
    Brodersen, Jakob
    et al.
    Lund university, Sweden.
    Chapman, Ben B.
    Lund university, Sweden.
    Nilsson, P. Anders
    Lund university, Sweden.
    Skov, Christian
    Silkeborg university, Denmark.
    Hansson, Lars-Anders
    Lund university, Sweden.
    Bronmark, Christer
    Lund university, Sweden.
    Fixed and Flexible: Coexistence of Obligate and Facultative Migratory Strategies in a Freshwater Fish2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 3, p. e90294-Article in journal (Refereed)
  • 22.
    Brönmark, C
    et al.
    Lund University.
    Hulthén, K
    Lund University.
    Nilsson, Anders
    Lund University.
    Skov, C
    DTU-AQUA.
    Hansson, LA
    Lund University.
    Brodersen, J
    Lund University .
    Chapman, BB
    Lund University .
    There and back again: migration in freshwater fishes2014In: Canadian Journal of Zoology, ISSN 0008-4301, E-ISSN 1480-3283, Vol. 92, no 6, p. 467-479Article in journal (Refereed)
    Abstract [en]

    Animal migration is an amazing phenomenon that has fascinated humans for long. Many freshwater fishes also show remarkable migrations, whereof the spectacular mass migrations of salmonids from the spawning streams are the most well known and well studied. However, recent studies have shown that migration occurs in a range of freshwater fish taxa from many different habitats. In this review we focus on the causes and consequences of migration in freshwater fishes. We start with an introduction of concepts and categories of migration, and then address the evolutionary causes that drive individuals to make these migratory journeys. The basis for the decision of an individual fish to migrate or stay resident is an evaluation of the costs and benefits of different strategies to maximize its lifetime reproductive effort. We provide examples by discussing our own work on the causes behind seasonal migration in a cyprinid fish, roach (Rutilus rutilus (L., 1758)), within this framework. We then highlight different adaptations that allow fish to migrate over sometimes vast journeys across space, including capacity for orientation, osmoregulation, and efficient energy expenditure. Following this we consider the consequences of migration in freshwater fish from ecological, evolutionary, and conservation perspectives, and finally, we detail some of the recent developments in the methodologies used to collect data on fish migration and how these could be used in future research.

  • 23. Cafaro, Philip
    et al.
    Butler, Tom
    Crist, Eileen
    Cryer, Paul
    Dinerstein, Eric
    Kopnina, Helen
    Noss, Reed
    Piccolo, John
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Taylor, Bron
    Vynne, Carly
    Washington, Haydn
    If we want a whole Earth, Nature Needs Half: a response to Buscher et al.2017In: Oryx, ISSN 0030-6053, E-ISSN 1365-3008, Vol. 51, no 3, p. 400-400Article in journal (Refereed)
  • 24.
    Calles, Olle
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Bergdahl, Daniel
    Ålens nedströms passage av vattenkraftverk: Före och efter åtgärd2009Report (Other academic)
    Abstract [en]

    Fiskarter som är beroende av att kunna röra sig mellan sötvatten och hav för att fullfölja sina livscykler stöter ofta på problem i reglerade vattendrag, eftersom vattenkraftverk skapar vandringshinder. Vanligen försöker man lösa dessa problem genom att anlägga fiskvägar vid hindren, för att åter göra det möjligt för fisken att passera. Fokus för sådana åtgärder har legat på just uppströms passage, medan nedströms passage av kraftverk sällan uppmärksammats och ytterst sällan åtgärdats. Denna rapport beskriver nedströmspassagen för ål vid ett vattenkraftverk i Ätran, före och efter åtgärd.

    Före åtgärd satt en fingaller med 20 mm spaltvidd och 63,4° lutning i intagskanalen till Ätrafors kraftverk i Ätran. Förlusten för ål på väg nedströms mot havet var omfattande och dödligheten var 72 %. De flesta ålar som dog klämdes fast på intagsgallret eller skadades vid turbinpassage. Åtgärden bestod i att sätta in ett nytt fingaller i intagskanalen med 18 mm spaltvidd och 35° lutning. Dessutom anlades flyktöppningar i gallrets övre del för att erbjuda ålen en alternativ väg förbi kraftverket. Efter åtgärd minskade dödligheten för ål till 10%. Ca. 80% av ålarna hittade ut genom flyktöppningarna och ingen av dem fastnade på det nya gallret. Det nya gallrets utökade yta ledde även till att fallförlusten minskade med som mest 170 mm, vilket innebär en ökad framtida produktion vid kraftverket om man lyckas med att hålla gallret rent från löv och drivgods.

  • 25.
    Calles, Olle
    et al.
    Karlstad University, Division for Environmental Sciences.
    Greenberg, L.A.
    Karlstad University, Division for Environmental Sciences.
    The pre- and postspawning movements of anadromous brown trout in relation to two low-head power plantsManuscript (Other academic)
  • 26.
    Calles, Olle
    et al.
    Karlstad University, Division for Environmental Sciences.
    Greenberg, Larry
    Karlstad University, Division for Environmental Sciences.
    Survival and movement of wild brown trout smolts past two power plantsManuscript (Other academic)
  • 27.
    Calles, Olle
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Griffioen, Ben
    IMARES Wageningen UR, Netherlands.
    Winter, Erwin
    IMARES Wageningen UR, Netherlands.
    Watz, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Nyqvist, Daniel
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Hagelin, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Gustafsson, Stina
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Österling, Martin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Piccolo, John
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Greenberg, Larry
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Bergman, Eva
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Fish Migration River Monitoring Plan2014Report (Other academic)
    Abstract [en]

    Fish have problems passing the Afsluitdijk Dam that separates the Wadden Sea from Lake IJsselmeer. To re-establish the connectivity and thereby allow fish to pass there is an initiative to build a fishway, the Fish Migration River (FMR), at the Konwerderzand sluice complex. This report proposes a monitoring program to evaluate the functionality of the FMR, but also to monitor passage possibilities through the existing sluices. The goals of the monitoring plan are to estimate 1) The overall passage past the Afsluitdijk dam to and from Lake IJsselmeer, 2) The attraction efficiency, 3) The passage efficiency, and 4) The use of the FMR as habitat and for acclimatization for the transition into freshwater.

    We present an overview of previous and ongoing monitoring in the area to establish the current state of knowledge. The report also includes a presentation of available and suitable methods for a future monitoring program considering the broad spectra of target fish species, and their abundances. The proposed program includes a description of study design and available techniques and cost-estimates of the monitoring program.

    The proposed program will target ten species: European eel (aal), flounder (bot), three-spined stickleback (dreidoornige stekelbaars), twait shad (fint), North Sea houting (houting), river lamprey (rieverprik), smelt (spiering), Atlantic salmon (zalm), brown trout (forel) and sea lamprey (zeeprik). The monitoring program includes plans for how to capture, tag and track the study fish using the most suitable tagging techniques. Furthermore, the most optimal sites for installation of automatic data detection stations are identified.

    The total cost for the proposed project is 3.5 M€ and covers both investments in equipment and costs for personnel. However, if costs for investments in techniques such as RFId-stations and fish counters are excluded, the total cost is reduced to 1 M€ for a program running two years before and four years after the completion of the FMR. The program is considered sufficient to evaluate the FMR at Kornwerederzand from the most important perspectives: the overall passage efficiency and the use of the FMR as habitat.

    It should be noted that this report is the first step towards a full-scale monitoring program, giving insight into possible methods, study design and associated costs. The next important step will be to develop the program in more detail and to start the initial phase of the monitoring project. We predict that such activities will identify the need for, and the relevance of, a more extensive monitoring program to study the effects of the FMR on a population level and on a large geographical scale.

  • 28.
    Calles, Olle
    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.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Temporal and spatial variation in quality of hyporheic water in one unregulated and two regulated boreal rivers2007In: River research and applications, ISSN 1535-1459, Vol. 23, no 8, p. 829-842Article in journal (Refereed)
    Abstract [en]

    This study describes the temporal and spatial variations in hyporheic water quality in three boreal rivers, the River Tobyälven, an unregulated river, the river Mangälven, a regulated river with a minimum discharge requirement and the river Järperudsälven, aregulated river without any minimum discharge requirements. A total of 43 permanent piezometers were used to measure dissolved oxygen (DO), temperature, electrical conductivity, pH, NO3 and NHþ4in the hyporheic water at 150mm and 300mmdepth, at monthly intervals from October 2001 to October 2002. Another seven piezometers were installed in brown trout redds and monitored during the incubation period, from December 2001 to April 2002. In the river Tobyälven, temporal patterns in hyporheic water chemistry correlated to variations in surface water chemistry and discharge. In the river Järperudsälven, the hyporheic water chemistry did not correlate to discharge or surface water chemistry. In the river Mangälven, the water chemistry was dominated by releases from a large upstream lake, and there were weak correlations between surface water chemistry and hyporheic water chemistry at some sites. The incubation conditions for brown trout eggs were most favourable in the unregulated river, characterized by high DO levels that remained high throughout the incubation period. In the river Järperudsälven the DO levels were variable during spawning, and then gradually declined to critically low levels during incubation, whereas in the river Mangälven the DO conditions were intermediate and stable. Thus we observed a stronger coupling between surface water conditions and hyporheic conditions, i.e. vertical connectivity, in the unregulated river than in the regulated river with minimum flow requirements, which in turn was stronger than in the river without minimum flow requirements.

  • 29.
    Carlsson, Niclas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Effekten av en kraftverksdamm på vandringsframgång hos migrerande öringsmolt2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Dammar fungerar som barriärer för migrerande fisk i rinnande vatten med minskad konnektivitet som följd. Predation och navigationssvårigheter är två stora orsaker till att nedströmsvandrande smolt uppvisar en låg vandringsframgång genom dammar. I Svedån undersöktes vandringsframgången för öringsmolt i en dammsträcka mot en fritt strömmande kontrollsträcka under perioden 15 april och 23 maj 2016. PIT-tagteknik (Passive Integrated Transponder) användes där totalt 117 öringar märktes med 12 mm PIT tag eller 23 mm PIT tag och följdes när de simmade förbi fyra installerade antennstationer som avgränsade de båda sträckorna. Resultatet visade en signifikant lägre vandringsframgång för de 29 öringarna i dammsträckan än för de 4 i kontrollsträckan, där endast 13,8% passerade dammsträckan och 75% passerade kontrollsträckan. Antal analyserad öring på kontrollsträckan var få, vilket skapar osäkerhet kring skattning på vandringsframgång på kontrollsträckan. Resultatet visar dock samma mönster från liknande studier som utförts rörande nedströmsvandrande öringsmolt. Orsakerna till den låga vandringsframgången kunde ej utredas men troliga orsakerna var predation, navigeringssvårigheter samt tvekan till passage vid dammens ytspill.

  • 30. Chapman, B.B.
    et al.
    Hulthén, K.
    Brönmark, C.
    Nilsson, Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Skov, C.
    Hansson, L-A.
    Brodersen, J.
    Shape up or ship out: migratory behaviour predicts morphology across spatial scale in a freshwater fish2015In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 84, p. 1187-1193Article in journal (Refereed)
  • 31.
    de Paiva Affonso, Igor
    et al.
    Universidade Estadual de Maringá, Brazil; Universidade Tecnológica Federal do Paraná, Brazil.
    Cucolo Carling, Leticia
    Universidade Estadual de Maringá, Maringá, Brazil.
    Massato Takemoto, R
    Núcleo de Pesquisas em Limnologia Ictiologia e Aqüicultura – Nupélia, Maringá, Brazil.
    Carlos Gomez, Luiz
    Universidade Estadual de Maringá, Maringá, Brazil; Núcleo de Pesquisas em Limnologia Ictiologia e Aqüicultura – Nupélia, Maringá, Brazil.
    Nilsson, Per Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Light-triggered eye-fluke behavior may enhance parasite life-cycle progression2017In: Frontiers in Ecology and the Environment, ISSN 1540-9295, E-ISSN 1540-9309, Vol. 15, no 6, p. 340-341Article in journal (Refereed)
  • 32.
    Delin, Jasmine
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Ökar blåmesen (Parus caeruleus) sin födosöksaktivitet när de tillhör en flock?2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 33.
    Dietrich, Anna
    et al.
    Umeå University, Sweden.
    Lind, Lovisa
    Umeå University, Sweden.
    Nilsson, Christer
    Umeå University, Sweden.
    Jansson, Roland
    Umeå University, Sweden.
    The Use of Phytometers for Evaluating Restoration Effects on Riparian Soil Fertility2014In: Journal of Environmental Quality, ISSN 0047-2425, E-ISSN 1537-2537, Vol. 43, no 6, p. 1916-1925Article in journal (Refereed)
    Abstract [en]

    The ecological restoration of streams in Sweden has become increasingly important to counteract effects of past timber floating. In this study, we focused on the effect on riparian soil properties after returning coarse sediment (cobbles and boulders) to the channel and reconnecting riparian with instream habitats. Restoration increases habitat availability for riparian plants, but its effects on soil quality are unknown. We also analyzed whether the restoration effect differs with variation in climate and stream size. We used standardized plant species to measure the performance of a grass (Phleum pratense L.) and a forb (Centaurea cyanus L.) in soils sampled in the riparian zones of channelized and restored streams and rivers. Furthermore, we analyzed the mass fractions of carbon (C) and nitrogen (N) along with the proportions of the stable isotopes C-13 and N-15 in the soil, as well as its grain size composition. We found a positive effect of restoration on biomass of phytometers grown in riparian soils from small streams, indicating that restoration enhanced the soil properties favoring plant performance. We suggest that changed flooding with more frequent but less severe floods and slower flows, enhancing retention, could explain the observed patterns. This positive effect suggests that it may be advantageous to initiate restoration efforts in small streams, which make up the highest proportion of the stream network in a catchment. Restoration responses in headwater streams may then be transmitted downstream to facilitate recovery of restored larger rivers. If the larger rivers were restored first, a slower reaction would be expected.

  • 34.
    Eckstein, Rolf Lutz
    Uppsala University.
    Nitrogen retention by Hylocomium splendens in a subarctic birch woodland2000In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 88, no 3, p. 506-515Article in journal (Refereed)
  • 35.
    Eckstein, Rolf Lutz
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences. Uppsala University.
    Karlsson, P S
    Uppsala University.
    Above-ground growth and nutrient use by plants in a subarctic environment: Effects of habitat, life-form and species1997In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 79, no 2, p. 311-324Article in journal (Refereed)
  • 36.
    Eckstein, Rolf Lutz
    et al.
    Uppsala University.
    Karlsson, P S
    Uppsala University.
    Recycling of nitrogen among segments of Hylocomium splendens as compared with Polytrichum commune: Implications for clonal integration in an ectohydric bryophyte1999In: OIKOS, Vol. 86, no 1, p. 87-96Article in journal (Refereed)
    Abstract [en]

    Physiological integration in clonal plants, which can be assumed to be dependent on vascular connections among ramets, is associated with several potential benefits, especially in nutrient-poor environments. However, some experimental evidence indicates that ectohydric bryophytes, i.e. species lacking specialised tissues for internal water conduction, also have physiologically integrated ramets. We tested this hypothesis by analysing nitrogen dynamics and tracing movements of a 15 N label among interconnected ramets of the ectohydric Hylocomium splendens over one season. The observed patterns were compared with translocation patterns in Polytrichum commune, an endohydric species that is known to show a high degree of clonal integration. Our aims were (1) to evaluate the degree of physiological integration among segments in H. splendens and (2) to study whether the pattern of 15 N movement obtained matched those depicted by changes in total nitrogen pool size. Current-year segments (G0) of both species were identified as strong sinks for nitrogen owing to their considerable increase in the 15 N pool during the season. In P. commune all other segments types showed a net loss of 15 N from June to September, which was probably due to autumn resorption of nitrogen to subterranean structures. In H. splendens one-year-old segments (G1) increased their 15 N pool, while older green segments (G2+) lost 50% of their initially absorbed 15 N. All the label lost from these source segments could be recovered in G0 and G1 segments. We suppose that most of the recycled nitrogen is provided by degeneration of three-year-old segments, which turn brown in parallel with the reallocation of nitrogen during the season. The high degree of physiological integration in H. splendens is discussed with respect to its life history and ecosystem nitrogen cycling.

  • 37.
    Eckstein, Rolf Lutz
    et al.
    Uppsala University.
    Karlsson, P S
    Uppsala University.
    Variation in nitrogen-use efficiency among and within subarctic graminoids and herbs2001In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 150, no 3, p. 641-651Article in journal (Refereed)
  • 38.
    Eckstein, Rolf Lutz
    et al.
    Uppsala University.
    Karlsson, P S
    Uppsala University.
    Weih, M
    Uppsala University.
    Leaf life span and nutrient resorption as determinants of plant nutrient conservation in temperate-arctic regions1999In: New phytologist, Vol. 143, no 1, p. 177-189Article in journal (Refereed)
  • 39.
    Eckstein, Rolf Lutz
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences. Uppsala University.
    Karlsson, P S
    Uppsala University.
    Weih, M
    Uppsala University.
    The significance of resorption of leaf resources for shoot growth in evergreen and deciduous woody plants from a subarctic environment1998In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 81, no 3, p. 567-575Article in journal (Refereed)
  • 40.
    Edwartz, Johannes
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Weight losses of Green tea and Rooibos tea in an aquatic environment: The importance of leaching when estimating decomposition rates2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Leaching is one of the major processes occurring when organic litter is decomposed and is often completed within a few days when litter enters aquatic environments. It is important that leaching is addressed when studying microbial and invertebrate decomposition rates in order to avoid overestimations. The traditional litter bag method that has been used to measure decomposition rates in both terrestrial and aquatic environments has in recent years been challenged by the new and widely adopted tea bag index (TBI). Both methods, however, fail to bring a standardized methodology for separating and recognizing weight losses of litter due to leaching and biotic decomposition. Through a field experiment in two streams with different water discharge, this study has focused on exploring the leaching phase and post-leaching phase of the tea products used in TBI. The results unveiled that 20% of rooibos tea’s and 44% of green tea’s initial weight was lost to leaching within three days (72 hours) of the experiment. After the 72nd hour, both teas remained in a stabilized phase until the end of the experiment (120 hours). Water discharge had no significant effect on neither of the tea-weights during or after the leaching phase. This study recommends that weight loss through the leaching phase are taken into account in future studies and advocate the development of an updated TBI protocol where leaching losses are recognized. If not, overestimations of active decomposition rates will be made and may result in compromised conclusions.

  • 41.
    Ekström, Sara M.
    et al.
    Lund University.
    Sandahl, Margareta
    Lund University.
    Nilsson, Per Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences. Lund University.
    Kleja, Dan B.
    Swedish University of Agricultural Sciences.
    Kritzberg, Emma S.
    Lund University.
    Reactivity of dissolved organic matter in response to acid deposition2016In: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 78, no 3, p. 463-475Article in journal (Refereed)
    Abstract [en]

    Fluvial export of organic matter from the terrestrial catchment to the aquatic system is a large and increasing carbon flux. The successful reduction in sulfuric acid deposition since the 1980s has been shown to enhance the mobility of organic matter in the soil, with more terrestrially derived dissolved organic matter (DOM) reaching aquatic systems. Changes in soil acidity also affect the quality of the DOM. In this study we explore the consequences this may have on the reactivity and turnover of the terrestrially derived DOM as it reaches the aquatic system. DOM of different quality (estimated by absorbance, fluorescence and size exclusion chromatography) was produced through extraction of boreal forest O-horizon soils from podzol at two sulfuric acid concentrations corresponding to natural throughfall in spruce forest in Southern Sweden around 1980 and today. Extraction was done using two different methods, i.e. field leaching and laboratory extraction. The DOM extracts were used to assess if differences in acidity generate DOM of different reactivity. Three reactivity experiments were performed: photodegradation by UV exposure, biodegradation by bacteria, and biodegradation after UV exposure. Reactivity was assessed by measuring loss of dissolved organic carbon and absorbance, change in fluorescence and molecular weight, and bacterial production. DOM extracted at lower sulfuric acid concentration was more susceptible to photooxidation, and less susceptible to bacterial degradation, than DOM extracted at a higher sulfuric acid concentration. Thus the relative importance of these two turnover processes may be altered with changes in acid deposition.

  • 42.
    Enefalk, Åsa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Bergman, Eva
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Effect of fine wood on juvenile brown trout behaviour in experimental stream channels2016In: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, Vol. 25, no 4, p. 664-673Article in journal (Refereed)
    Abstract [en]

    In-stream wood can increase shelter availability and prey abundance for stream-living fish such as brown trout, Salmo trutta, but the input of wood to streams has decreased in recent years due to harvesting of riparian vegetation. During the last decades, fine wood (FW) has been increasingly used for biofuel, and the input of FW to streams may therefore decrease. Although effects of in-stream FW have not been studied as extensively as those of large wood (LW), it is probably important as shelter for small-sized trout. In a laboratory stream experiment, we tested the behavioural response of young-of-the-year wild brown trout to three densities of FW, with trout tested alone and in groups of four. Video recordings were used to measure the proportion of time allocated to sheltering, cruising and foraging, as well as the number of aggressive interactions and prey attacks. Cruising activity increased with decreasing FW density and was higher in the four-fish groups than when fish were alone. Foraging decreased and time spent sheltering in FW increased with increasing FW density. Our study shows that juvenile trout activity is higher in higher fish densities and that trout response to FW is related to FW density and differs from the response to LW as reported by others. © 2015 John Wiley & Sons A/S.

  • 43.
    Enefalk, Åsa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Watz, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Greenberg, Larry
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Bergman, Eva
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Winter sheltering by juvenile brown trout (Salmo trutta): Effects of stream wood and an instream ecothermic predator2017In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 62, no 1, p. 111-118Article in journal (Refereed)
    Abstract [en]

    In boreal streams, juvenile salmonids spend substantial amounts of time sheltering in the streambed and in stream wood, presumably as a means of protection against the physical environment and from terrestrial endothermic predators. Relatively little is known about sheltering by salmonids in response to instream ectothermic predators.We tested the effects of burbot (Lota lota) on the winter sheltering behaviour of PIT-tagged 0+ brown trout (Salmo trutta) in daylight and darkness. Sheltering in the streambed by trout was studied in the presence and absence of fine wood bundles.We found that the use of streambed and fine wood was lower in darkness than in daylight. Availability of fine wood significantly decreased sheltering in the streambed, and this effect was more pronounced in daylight than in darkness. The presence of a burbot significantly decreased sheltering in the streambed, had no effect on use of fine wood and resulted in a higher number of exposed trout.Our results indicate that juvenile brown trout decrease streambed sheltering in response to a burrowing, ectothermic predator.

  • 44. Eros, Tibor
    et al.
    Gustafsson, Pär
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Greenberg, Larry
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Forest-Stream linkages: Effects of Terrestrial Invertebrate Input and Light on Diet and Growth of Brown Trout (Salmo trutta) in a Boreal Forest Stream2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 5, p. 1-11Article in journal (Refereed)
    Abstract [en]

    Subsidies of energy and material from the riparian zone have large impacts on recipient stream habitats. Human-induced changes, such as deforestation, may profoundly affect these pathways. However, the strength of individual factors on stream ecosystems is poorly understood since the factors involved often interact in complex ways. We isolated two of these factors, manipulating the flux of terrestrial input and the intensity of light in a 2 x 2 factorial design, where we followed the growth and diet of two size-classes of brown trout (Salmo trutta) and the development of periphyton, grazer macroinvertebrates, terrestrial invertebrate inputs, and drift in twelve 20 m long enclosed stream reaches in a five-monthlong experiment in a boreal coniferous forest stream. We found that light intensity, which was artificially increased 2.5 times above ambient levels, had an effect on grazer density, but no detectable effect on chlorophyll a biomass. We also found a seasonal effect on the amount of drift and that the reduction of terrestrial prey input, accomplished by covering enclosures with transparent plastic, had a negative impact on the amount of terrestrial invertebrates in the drift. Further, trout growth was strongly seasonal and followed the same pattern as drift biomass, and the reduction of terrestrial prey input had a negative effect on trout growth. Diet analysis was consistent with growth differences, showing that trout in open enclosures consumed relatively more terrestrial prey in summer than trout living in covered enclosures. We also predicted ontogenetic differences in the diet and growth of old and young trout, where we expected old fish to be more affected by the terrestrial prey reduction, but we found little evidence of ontogenetic differences. Overall, our results showed that reduced terrestrial prey inputs, as would be expected from forest harvesting, shaped differences in the growth and diet of the top predator, brown trout.

  • 45.
    Gattringer, Johannes P.
    et al.
    Justus Liebig Univ Giessen, Res Ctr Biosyst Land Use & Nutr IFZ, Div Landscape Ecol & Landscape Planning, Giessen, Germany..
    Donath, Tobias W.
    Univ Kiel, Inst Nat Resource Conservat, Dept Landscape Ecol, Kiel, Germany..
    Eckstein, R. Lutz
    Karlstad Univ, Dept Environm & Life Sci Biol, Karlstad, Sweden..
    Ludewig, Kristin
    Justus Liebig Univ Giessen, Res Ctr Biosyst Land Use & Nutr IFZ, Div Landscape Ecol & Landscape Planning, Giessen, Germany..
    Otte, Annette
    Justus Liebig Univ Giessen, Res Ctr Biosyst Land Use & Nutr IFZ, Div Landscape Ecol & Landscape Planning, Giessen, Germany..
    Harvolk-Schoening, Sarah
    Justus Liebig Univ Giessen, Res Ctr Biosyst Land Use & Nutr IFZ, Div Landscape Ecol & Landscape Planning, Giessen, Germany..
    Flooding tolerance of four floodplain meadow species depends on age2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 5, article id e0176869Article in journal (Refereed)
    Abstract [en]

    Numerous restoration campaigns focused on re-establishing species-rich floodplain meadows of Central Europe, whose species composition is essentially controlled by regular flooding. Climate change predictions expect strong alterations on the discharge regime of Europe's large rivers with little-known consequences on floodplain meadow plants. In this study, we aim to determine the effects of flooding on seedlings of different ages of four typical flood meadow species. To this end, we flooded seedlings of two familial pairs of flood meadow species of wetter and dryer microhabitats for 2 weeks each, starting 2, 4, 6, and 8 weeks after seedling germination, respectively. We show that a 2-week-flooding treatment had a negative effect on performance of seedlings younger than 6 weeks. Summer floods with high floodwater temperatures may have especially detrimental effects on seedlings, which is corroborated by previous findings. As expected, the plants from wet floodplain meadow microhabitats coped better with the flooding treatment than those from dryer microhabitats. In conclusion, our results suggest that restoration measures may perform more successfully if seedlings of restored species are older than the critical age of about 6 weeks before a spring flooding begins. Seasonal flow patterns may influence vegetation dynamics of floodplain meadows and should, therefore, be taken into account when timing future restoration campaigns.

  • 46.
    Granberg, Mikael
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Political, Historical, Religious and Cultural Studies (from 2013). Karlstad University, Faculty of Health, Science and Technology (starting 2013), Centre for Climate and Safety (from 2013).
    Strong local government moving to the market?: The case of low carbon futures in the city of Örebro, Sweden2018In: Rethinking Urban Transitions: Politics in the Low Carbon City / [ed] Andrés Luque-Ayala, Simon Marvin and Harriet Bulkeley, Taylor & Francis, 2018, p. 129-145Chapter in book (Other academic)
    Abstract [en]

    Policy and practice at the local level is central in relating global standards and knowledge, national and regional climate change scenarios and policy decisions into particular climate action in a specific context (Bulkeley and Betsill, 2003; Elander et al., 2003; Lundqvist and Biel, 2007; Storbjörk, 2007; Storbjörk, 2010; Castán Broto and Bulkeley, 2012; van den Berg and Coenen, 2012; Romero-Lankao, 2012; Bulkeley et al., 2015). This means that cities, and their local governments, are central to understanding the implementation of international agreements (regimes), national and regional climate change policy. It needs to be stressed, however, that local governments are not just implementers of policy decision taken at higher levels of government. Local governments can, and perhaps have to, be forerunners in climate change policy and practice, as the sources and impacts of climate change are always local, national policy and international negotiations are not always successful, and national governments are not necessarily taking the lead (Gore and Robinson, 2009; Bulkeley et al., 2015; Bulkeley and Betsill, 2003). Local government action on climate change takes place in a specific local setting. It also takes place in a policy environment characterized by cross-cutting issues and cross pressure from government actors on international, national and regional levels, unfolding public sector reform, continuous policy development, and demands from businesses and citizens (Granberg et al., 2016). Accordingly, why and how cities act on climate change challenges is by no means a straightforward matter (Bulkeley et al., 2015) but, certainly, one that warrants critical research. This chapter focuses on local government low carbon action within the field of alternative energy production, zooming in on the organizational modes and on intermediary functions and actors in efforts aiming at low carbon transitions (cf. Bulkeley and Betsill, 2013; Hodson et al., 2013). In the Swedish context, low carbon transitions are of course connected to the ecological need to reduce GHG (greenhouse gas) emissions, mitigating future risks and impacts. But they are also increasingly connected to the more economic arguments connected to the concept of a carbon or fossil bubble (Schoenmaker et al., 2015; Rubin, 2015). That is, the idea that any investments made in fossil fuel-based companies are investments that will add to GHC emissions and, perhaps even more important from this perspective, fail to produce any long-term economic profits. According to this perspective, all viable investments need to be directed towards no-carbon solutions, businesses and markets or there will be serious negative economic impacts when the carbon bubble eventually bursts. The central questions of this chapter are how capacity-building for low carbon transitions evolves at the interface between state and market and what specific role local governments take in this interface. As already indicated above, this perspective is guided by the concept of intermediation through institutional experimentation (cf. Luque-Ayala et al., Chapter 2, this volume; also, Hodson and Marvin, 2009, 2012; Hodson et al., 2013). Intermediaries here are defined as entities that connect, translate and facilitate flows between different parties. The focus of the chapter is, more precisely, on systemic intermediation on a network level involving more than two parties (Hodson and Marvin, 2009). The intermediary role can be divided into facilitating, configuring and brokering (Stewart and Hyysalo, 2008). Accordingly, the aim of this chapter is to study local government efforts to build low carbon capacity by describing, critically examining and analysing local government climate action. In the case studied here, we can see the local government organization intermediating indirectly by trying to facilitate flows of both experience and capital between public and private actors but also directly as a market actor through a boundary hybrid organization facilitating connections between local government and market actors. A hybrid organization (cf. Koppell, 2006) is an organization that mixes value systems and logics of various spheres such as the state and the market (cf. Erlingsson et al., 2014; Montin, 2016). More precisely, the local government uses a 'green' investment fund, facilitating public-private networking and a municipal company in their efforts to advance a low carbon transition. The case studied follows the development of local government climate change action over the last decade in the Swedish city of Örebro. The city profiles itself as a forerunner in environmental issues and has formulated ambitious reduction targets. Sweden is often considered a pioneer in environmental governance (Lidskog and Elander, 2012), combining high ambitions at a national level, strong local government and robust policy guided by ecological modernization (Lundqvist, 2000; Zannakis, 2015). It has been stated that if Sweden still holds on to a leading international position in environmental governance it is probably due to activities at the local level (Granberg and Elander, 2007; Uggla and Elander, 2009; Hjerpe et al., 2014). Accordingly, Sweden provides an interesting context for studies of local government climate change action via market mechanisms, given its combination of strong local government with high (national and local) environmental ambitions. Arguably, drawing from this, if Sweden is to be perceived as a 'least likely' case for utilizing market mechanisms due to its strong and resourceful local government (cf. Flyvbjerg, 2006), then local government action in Sweden becomes a critical case worthy of critical inquiry. In the sections that follow, this chapter elaborates aspects integral to the case studied. First, it briefiy presents the Swedish local government system and its development, highlighting the presence of strong local governments and their central role in the Swedish government system. This is followed by a presentation of Swedish policy development within the fields of climate change, energy generation and GHG mitigation, again highlighting the central role given to Swedish local government. The chapter ends with a set of conclusions aimed at an integrated analysis of the Swedish government system, national policy developments and the local component of the case study showing how these three components are, in fact, one integrated multilevel case. It is clear that the local government uses a form of institutional experimentation that mixes value systems and logics of both state and market in its strive to becoming a 'climate smart' city.

  • 47.
    Greenberg, Larry
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Eklöv, Anders
    Effects of Predation and Intraspecific Interactions on Habitat Use and Foraging by Brown Trout in Artificial Streams1997In: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, Vol. 6, no 1, p. 16-26Article in journal (Refereed)
    Abstract [en]

    We studied habitat use, foraging rates and behavior of 10 cm and 12 cm long brown trout, Salmo trutta, at two densities, 1.5 and 3.0 fish. m−2, in artificial streams that contained either the amphipod, Gammarus pulex, alone or G. pulex together with the piscivore, northern pike, Esox lucius. Gammarus were stocked in and largely restricted to the pools at a density of 128 Gammurus. m−2. pool−1 Large trout (12 cm) used pools more and riffles less when small trout (10 cm) were present than when small trout were absent. Small trout consumed fewer Gammarus when together with large trout than when alone, but showed no difference in habitat use in the presence and abscnce of large trout. Habitat use and number of Gammarus consumed per trout were not affected by trout density for either size-class when alone. For both size-classes of trout, use of pools and foraging rates were higher in the absence than in the presence of pike, and pike primarily resided in the pools. The number of aggressive interactions by both size-classes of trout decreased when pike was present. Our results indicate that for habitats that differ in food resources and predation risk, size structure may affect habitat use and foraging by brown trout.

  • 48.
    Gustafsson, Pär
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Forest – stream linkages: Brown trout (Salmo trutta) responses to woody debris, terrestrial invertebrates and light2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Forests surrounding streams affect aquatic communities in numerous ways, contributing to energy fluxes between terrestrial and lotic ecosystems. The five papers in this thesis focus on woody debris, terrestrial invertebrates and light, three factors influenced by riparian zone structure, potentially affecting streams and brown trout (Salmo trutta). The individual strength of these stressors and their interactions with each other are not well studied, and their qualitative effects may differ both spatially and temporally as well as with the size-structure of specific fish populations.

    Using a combination of laboratory and field experiments, I examined the effects of woody debris, terrestrial invertebrates and light on prey availability and on the growth rates, diets and behavior of different size-classes of trout. My field experiments showed that addition of high densities of large wood affected trout growth in a positive way. This positive effect of large wood on trout growth may be related to prey abundance, as indicated by the high standing crop of aquatic macroinvertebrates on the wood. The positive effects on trout may also be related to decreased energy expenditures in wood habitats, as trout increased the ratio between numbers of prey captured and time spent active and that swimming activity and level of aggression decreased as wood densities were increased in a laboratory experiment. Terrestrial invertebrates are generally assumed to be a high quality prey resource for fish and my field experiments showed that reduction of terrestrial invertebrate inputs had a negative effect on trout growth. The availability of terrestrial prey in the stream was also coupled to trout diet and linked to growth, as fish with high growth rates had high proportions of terrestrial prey in their diets. Light, measured as PAR, did not have an effect on chlorophyll biomass, nor was there an effect on aquatic macroinvertebrates or trout. Hence, even if light levels were sufficient for increased photosynthesis, other factors such as low nutrient content may have limited the effects. Many of my results were dependent on fish-size. I observed, for example, that large trout had higher capture rates on surface-drifting terrestrial prey than small trout when prey densities were intermediate or high, but at low prey densities, the consumption of terrestrial prey by large and small trout were similar. Moreover, although large wood and terrestrial invertebrates affected growth of both small and large trout, the effects were generally more consistent for large trout.

    Although changes in riparian forests typically induce an array of interacting effects that certainly call for further research, the overall conclusion from this thesis is that many of the factors I have studied have profound effects on stream biota and trout. The positive effects from large wood also propose that adding trees to streams may partly compensate for negative effects associated with riparian deforestation.

  • 49.
    Gustafsson, Stina
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Habitat compensation in nature-like fishways: Effects on benthos and fish2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The construction of nature-like fishways has become an increasingly common measure to restore longitudinal connectivity in streams and rivers affected by hydroelectric development. These fishways also have the potential to function as habitat compensation measures when running waters have been degraded or lost. The habitat potential has however often been overlooked, and therefore the aim of this thesis was to examine the potential of nature-like fishways for habitat compensation, with special focus on the effect of added habitat heterogeneity.

    This thesis examines the effects of habitat diversity on the macroinvertebrate family composition and functional organization in a nature-like, biocanal-type fishway. The biocanal contained four habitat types; riffle, pool, braided channel and floodplain. The effects of habitat diversity and large woody debris on brown trout habitat choice was also investigated in the biocanal. In addition, and prior to introduction of the threatened freshwater pearl mussel into the biocanal, the suitability of different brown trout strains as hosts for the mussel was examined.

    The results show that the habitat heterogeneity in the biocanal contributed to an increased macroinvertebrate family diversity. The functional organization of the macroinvertebrate community suggests that it was a heterotrophic system and more functionally similar to the main river than to the small streams that it was created to resemble. Brown trout habitat choice studies showed that high densities of large woody debris increase the probability of fish remaining at the site of release. Testing of different brown trout strains as host for the freshwater pearl mussel revealed that both wild and hatchery-reared brown trout strains were suitable hosts. In summary, the results indicate that it is possible to create a fish passage with added value through its high habitat function and that nature-like fishways can be designed to reach multiple species restoration goals.

  • 50.
    Gustafsson, Stina
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Macroinvertebrate colonization of a nature-like fishway: The effects of habitat designManuscript (preprint) (Other academic)
    Abstract [en]

    Nature-like fishways are designed to imitate the characteristics of natural streams, thereby providing passage and habitat for a variety of aquatic organisms. To develop the concept of nature-like design, a 500-meter long nature-like bypass channel, termed the biocanal, was constructed at the Eldforsen hydroelectric facility, Sweden. It included four habitat types; riffle, pool, floodplain and braided (i.e. with islands) habitats, each replicated three times.  The biocanal resembled a natural stream in terms of hydraulics, gradient, flow regime, substrate etc. and provided a range of habitats to potentially harbor a large biodiversity. Thus the biocanal had a much more varied instream environment than those of conventional fishways. To test the prediction that the biocanal had a positive effect on biodiversity, we compared the physical habitat and benthic fauna composition both among the four biocanal habitat types and with six natural reference streams. After two years 66.7% of the benthic fauna families found in the reference streams had colonized the biocanal. Families present in the reference streams, but not in the biocanal, were predominantly slow colonizers or taxa linked to riparian vegetation, which was scarce and in an early successional stage in the biocanal.

    In the biocanal, pool and floodplain habitats contained the highest number of families, the highest family diversity (Shannon-Weaver) and the highest densities of Ephemeroptera, Plecoptera and Trichoptera. Since these habitats contained more families and had higher diversities than the riffle habitats which are typical of conventional nature-like fishways, we suggest that the construction of biocanals indeed possesses the potential for high biodiversity. 

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