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  • 51.
    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, Rolf Lutz
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    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.

  • 52.
    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.

  • 53.
    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.

  • 54.
    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.

  • 55.
    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.

  • 56.
    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. 

  • 57. Gustafsson, Stina
    The functional organization of the macroinvertebrate community in a nature-like fishway with habitat compensation propertiesManuscript (preprint) (Other academic)
    Abstract [en]

    Habitat compensation in streams can be integrated in the construction of nature-like fishways, creating structures that both facilitate passage and provide habitat. Few existing nature-like fishways, however, have been designed to maximize the habitat function. In 2009 a nature-like fishway with habitat compensation properties, termed the biocanal, was constructed in Eldforsen, Sweden. The functional feeding group approach was used to investigate the functional organization of the benthic community in the biocanal two years after its construction. Samples were also collected from six natural creeks in the area to be used as references. Comparisons of functional feeding group ratios, acting as substitutes of ecosystem attributes, implied that both the biocanal and the reference creeks were heterotrophic systems enriched in suspended FPOM. The ratios also showed that the systems contained an abundance of stable substrates for filter feeders and scrapers. The study also showed that even though the benthic fauna community composition in the biocanal and in reference creeks in the area differ, all functional feeding groups found in the six reference creeks where present in the biocanal. We therefore believe that the ecological function of the biocanal is similar to that of the natural reference creeks in the area. 

  • 58.
    Gustafsson, Stina
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Calles, Olle
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Jostein, Skurdal
    Stiftelsen Lillehammer museum.
    Vezza, Paolo
    Department of Environment, Land and Infrastructure Engineering Politecnico di Torino.
    Comoglio, Claudio
    Department of Environment, Land and Infrastructure Engineering Politecnico di Torino.
    Österling, Martin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Functional organization and colonization of macroinvertebrates in a nature-like fishway with added habitat heterogeneityManuscript (preprint) (Other academic)
  • 59.
    Gustafsson, Stina
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Calles, Olle
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Skurdal, Jostein
    Österling, Martin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Invertebrate colonization of a nature-like fishway in Eldforsen, Sweden; the effect of habitat design2012Conference paper (Refereed)
  • 60.
    Gustafsson, Stina
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Calles, Olle
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Österling, Martin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    A test for suitable fish hosts for the threatened freshwater pearl mussel (Margaritifera margaritifera) prior to reintroductionManuscript (preprint) (Other academic)
  • 61.
    Gustafsson, Stina
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Österling, Martin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Nilsson, Per Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Calles, Olle
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Brown trout habitat choice: relative importance of woody debris and river morphology in nature-like fishwaysManuscript (preprint) (Other academic)
  • 62.
    Gustafsson, Stina
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Österling, Martin
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Skurdal, Jostein
    Schneider, Lea Dominique
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Calles, Olle
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Macroinvertebrate colonization of a nature-like fishway: The effects of adding habitat heterogeneity2013In: Ecological Engineering: The Journal of Ecosystem Restoration, ISSN 0925-8574, Vol. 61, p. 345-353Article in journal (Refereed)
    Abstract [en]

    Nature-like fishways are designed to imitate the characteristics of natural streams, thereby providing both fish passage and habitat for a variety of aquatic organisms. To date, however, the potential for habitat rehabilitation of nature-like fishways has not been fully realized. To develop the concept of how to design a nature-like fishway, a 500-m long nature-like fishway, 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), each replicated three times. The riffle sections were considered controls for typical Swedish nature-like fishways. Thus the biocanal had a more varied in-stream 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 of the more diverse habitat types in the biocanal to the riffle habitats. We also made comparisons between the biocanal and six natural reference streams in the area. After two years, 63% 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 along 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. (C) 2013 Elsevier B.V. All rights reserved.

  • 63.
    Gustavsson, Alexander
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Påverkan av habitatkomplexitet och infektionsgrad av flodpärlmusslans larver på öringinteraktioner2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Many species are today threatened by extinction. In streams and rivers, the historical clearing of obstacles in favour of transportation of floating timber has led to a decrease in the important habitat complexity. The larvae of freshwater pearl mussel (Margaitifera margaritifera) lives as a parasite on the gills of brown trout (Salmo trutta)wich effects the host negatively. In this study the effects of the activity, the amount of prey captured and the amount of initiated interaction with other trouts in different habitat complexity and different grade of infection from glochidia was investigated. The behaviour of brown trout was studies in the laboratory at Karlstads university in 2015. Analyses from data collected in laboratory studies at Karlstad University showed that there was no significant difference in activity or the amount of food captured between fish in complex and homogeneous habitats with high or low infection. In the case of initiated interactions there was a significantly higher rate of initiated interactions in homogeneous habitats than in complex habitats. The understanding of how the host is affected by parasites and even a changing habitat is important to be able to protect sensitive species with a parasitic lifecycle. 

  • 64.
    Hagelin, Anna
    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).
    Reintroducing Atlantic salmon to once native areas: Competition between Atlantic salmon, brown trout and graylingManuscript (preprint) (Other academic)
    Abstract [en]

    Worldwide declines in salmonid populations have generated major interest in conservation and restoration of wild populations and riverine habitats. Plans to re-introduce species to rivers where they previously occurred raises questions as to their potential impact on these systems after so many years. In the River Klarälven, Atlantic salmon (Salmo salar) has been extinct from the upper reaches of its former distribution for more than 50 years due to the construction of hydropower dams. Here we study competitive interactions between Atlantic salmon and two other salmonids, grayling (Thymallus thymallus) and brown trout (Salmo trutta), that presently occur in the upper reaches of the river. We examine foraging rates, aggression and activity of juvenile Atlantic salmon, grayling and brown trout in allopatry at three different densities and in sympatry with one or both potential competitors in laboratory flumes. We found that Atlantic salmon captured prey less frequently in the presence of brown trout and grayling, whereas grayling and brown trout affected each other, but were unaffected by Atlantic salmon. Rates of aggression initiated by salmonids in allopatry versus sympatry revealed differences between fish species, with grayling being the most aggressive and salmon the least. There was also a difference in activity, i.e. time spent cruising or holding position, between the species, with grayling being the most active and salmon the least. These results suggest that re-introduction of Atlantic salmon probably will have little impact on grayling and brown trout, whereas high densities of grayling and brown trout could affect the success of re-introducing Atlantic salmon.

  • 65.
    Hallbäck, Christoffer
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Inmätning och utvärdering av potentiellt habitat för Dendrocopos leucotos vid Erken: Mätning och beräkning av mängden levande och döda lövträd.2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The white-backed woodpecker has been a highly threatened in Sweden since 1970 due to drastically changed habitats as a result from industrialized forestry methods with a high focus on conifers. Today there are only 2 known breeding pairs left at Dalälven in Sweden. Compared to Finland and Latvia the white-backed woodpecker exhibits a strong presence with large populations as the forestry industry in these countries differs from Sweden in terms of what type of trees they use and how they manage dead wood. The purpose of this study is to assess whether an area at lake Erken’s northern shore called Hasselhorn in Stockholm County achieves the guidelines determined by Naturvårdsverket. Naturvårdsverket has determined that the white-backed woodpecker at least need 20m3/ha dead deciduous trees in a habitat and an average age of >80 years to be considered as an optimal area for the white-backed woodpecker. The focus area was localized with IR-images to determine an area rich with deciduous trees and an area of 100ha was drafted. Sixty sample points were randomized in the area. All living and dead trees at each points were measured with a tree caliper and clinometer to determine the amount of wood in m3/ha. Age was determined visually for each sample point. The study showed that Hasselhorn currently does no achieve the optimal status for all parameters in the study to make it a suitable habitat for the white-backed woodpecker. On the other hand, the area does meet the guideline set by Naturvårdsverket of more than 20m3/ha dead deciduous wood and more than 75% deciduous trees in the area, however it does not show an average age of >80 years. Species distribution of living deciduous trees exhibits large volumes of aspen, which is considered to be a main source of food since they contain the type of bugs preferred by the white-backed woodpecker. With the right conservation methods, the study shows that Hasselhorn can become a viable habitat for the white-backed woodpecker in the near future.

  • 66.
    Hansen, Joan H.
    et al.
    Technical University of Denmark.
    Skov, Christian
    Technical University of Denmark.
    Baktoft, Henrik
    Technical University of Denmark.
    Brönmark, Christer
    Lund University.
    Chapman, Ben B.
    University of Manchester.
    Hulthén, Kaj
    Lund University.
    Hansson, Lars-Anders
    Lund University.
    Nilsson, Per Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013). Lund University.
    Brodersen, Jakob
    EAWAG Swiss Federal Institute of Aquatic Science and Technology, University of Bern.
    Ecological consequences of animal migration: Prey partial migration affects predator ecology and prey communities2019In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, p. 1-15Article in journal (Refereed)
    Abstract [en]

    Patterns of animal migration and the ecological forces that shape them have been studied for centuries. Yet ecological impacts caused by the migration, such as altered predator–prey interactions and effects on community structure, remain poorly understood. This is to a large extent due to the scarcity of naturally replicated migration systems with negative controls, that is, ecosystems without migration. In this study, we tested whether partial migration of certain species within the overall prey community affects foraging ecology of top predators and thereby alters energy pathways in food webs. We carried out the study in independent replicated freshwater lake systems, four with and four without opportunity for prey migration. Specifically, we compared predator foraging mode in lakes where cyprinid prey fish perform seasonal partial migrations into connected streams with lakes lacking migratory opportunities for prey fish. We found clear seasonal bottom-up effects of prey migration on predators, including changes in size structure and total biomass of ingested prey, size-specific changes in littoral versus pelagic origin of diet, and a higher degree of feast-and-famine for predators in systems with migratory prey. Our analyses further showed that partially migratory prey species constitute a larger part of the prey community in systems that allow migration. Hence, prey migrations have important implications for predator foraging ecology and may cause seasonal shifts in the importance of their supporting energy pathways. We suggest that such bottom-up effects of partial migration may be a widespread phenomenon both in aquatic and in terrestrial ecosystems. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.

  • 67.
    Hasselquist, Eliza Maher
    et al.
    Umeå University, Sweden.
    Nilsson, Christer
    Umeå University, Sweden.
    Hjalten, Joakim
    Umeå University, Sweden.
    Jørgensen, Dolly
    Umeå University, Sweden.
    Lind, Lovisa
    Umeå University, Sweden.
    Polvi, Lina E.
    Umeå University, Sweden.
    Time for recovery of riparian plants in restored northern Swedish streams: a chronosequence study2015In: Ecological Applications, ISSN 1051-0761, E-ISSN 1939-5582, Vol. 25, no 5, p. 1373-1389Article in journal (Refereed)
    Abstract [en]

    A lack of ecological responses in stream restoration projects has been prevalent throughout recent literature with many studies reporting insufficient time for recovery. We assessed the relative importance of time, site variables, and landscape setting for understanding how plant species richness and understory productivity recover over time in riparian zones of northern Swedish streams. We used a space-for-time substitution consisting of 13 stream reaches restored 5-25 years ago, as well as five unrestored channelized reference reaches. We inventoried the riparian zone for all vascular plant species along 60-m study reaches and quantified cover and biomass in plots. We found that while species richness increased with time, understory biomass decreased. Forbs made up the majority of the species added, while the biomass of graminoids decreased the most over time, suggesting that the reduced dominance of graminoids favored less productive forbs. Species richness and density patterns could be attributed to dispersal limitation, with anemochorous species being more associated with time after restoration than hydrochorous, zoochorous, or vegetatively reproducing species. Using multiple linear regression, we found that time along with riparian slope and riparian buffer width (e.g., distance to logging activities) explained the most variability in species richness, but that variability in total understory biomass was explained primarily by time. The plant community composition of restored reaches differed from that of channelized references, but the difference did not increase over time. Rather, different time categories had different successional trajectories that seemed to converge on a unique climax community for that time period. Given our results, timelines for achieving species richness objectives should be extended to 25 years or longer if recovery is defined as a saturation of the accumulation of species over time. Other recommendations include making riparian slopes as gentle as possible given the landscape context and expanding riparian buffer width for restoration to have as much impact as possible.

  • 68.
    Hattermann, Dirk
    et al.
    Justus Liebig University, Giessen, Germany.
    Bernhardt-Römermann, Markus
    Friedrich Schiller University , Jena, Germany.
    Otte, Annette
    Justus Liebig University, Giessen, Germany.
    Eckstein, Rolf Lutz
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    New insights into island vegetation composition and species diversity: Consistent and conditional responses across contrasting insular habitats at the plot-scale2018In: PLoS ONE, E-ISSN 1932-6203, Vol. 13, no 7, article id e0200191Article in journal (Refereed)
    Abstract [en]

    Most island-ecology studies focus on the properties of entire island communities, thus neglecting species-environment relationships operating at the habitat-level. Habitat-specific variation in the strength and sign of these relationships will conceal patterns observed on the island scale and may preclude a mechanistic interpretation of patterns and processes. Habitat-specific species-environment relationships may also depend on the descriptor of ecological communities. This paper presents a comprehensive plot-based analysis of local vegetation composition and species diversity (species richness and species evenness) of (i) rocky shore, (ii) semi-natural grassland and (iii) coniferous forest habitats in three Baltic archipelagos in Sweden. To identify differences and consistencies between habitats and descriptors, we assessed the relative contributions of the variable-sets “region”, “topography”, “soil morphology”, “soil fertility”, “soil water”, “light availability”, “distance” and “island configuration” on local vegetation composition, species richness and species evenness. We quantified the impact of “management history” on the descriptors of local grassland communities by a newly introduced grazing history index (GHI). Unlike species diversity, changes in vegetation composition were related to most of the variable-sets. The relative contributions of the variable-sets were mostly habitat-specific and strongly contingent on the descriptor involved. Within each habitat, richness and evenness were only partly affected by the same variable-sets, and if so, their relative contribution varied between diversity proxies. Across all habitats, soil variable-sets showed highly consistent effects on vegetation composition and species diversity and contributed most to the variance explained. GHI was a powerful predictor, explaining high proportions of variation in all three descriptors of grassland species communities. The proportion of unexplained variance was habitat-specific, possibly reflecting a community maturity gradient. Our results reveal that species richness alone is an incomplete representation of local species diversity. Finally, we stress the need of including habitat-based approaches when analyzing complex species-environment relationships on islands.

  • 69.
    Hedgespeth, Melanie L.
    et al.
    Lund University.
    Nilsson, Per Anders
    Lund University.
    Berglund, Olof
    Lund university.
    Ecological implications of altered fish foraging after exposure to an antidepressant pharmaceutical2014In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 151, p. 84-87Article in journal (Refereed)
  • 70.
    Hedgespeth, Melanie
    et al.
    Lund University.
    Nilsson, Per Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013). Lund University.
    Berglund, Olof
    Lund University.
    Assessing potential vulnerability and response of fish to simulated avian predation after exposure to psychotropic pharmaceuticals2016In: Toxics, ISSN 2305-6304, Vol. 4, no 9Article in journal (Refereed)
    Abstract [en]

    Psychotropic pharmaceuticals present in the environment may impact organisms both directly and via interaction strengths with other organisms, including predators; therefore, this study examined the potential effects of pharmaceuticals on behavioral responses of fish to avian predators. Wild-caught juvenile perch (Perca fluviatilis) were assayed using a striking bird model after a seven-day exposure to psychotropic pharmaceuticals (the antidepressants fluoxetine or sertraline, or the -blocker propranolol) under the hypotheses that exposure would increase vulnerability to avian predation via increasing the probability of predator encounter as well as degrading evasive behaviors upon encounter. None of the substances significantly affected swimming activity of the fish, nor did they increase vulnerability by affecting encounter probability or evasive endpoints compared to control treatments. Counter to our expectations, fish exposed to 100 g/L fluoxetine (but no other concentrations or pharmaceuticals) were less likely to enter the open area of the arena, i.e., less likely to engage in risky behavior that could lead to predator encounters. Additionally, all fish exposed to environmentally relevant, low concentrations of sertraline (0.12 g/L) and propranolol (0.1 g/L) sought refuge after the simulated attack. Our unexpected results warrant further research as they have interesting implications on how these psychotropic pharmaceuticals may affect predator-prey interactions spanning the terrestrial-aquatic interface.

  • 71. Henrikson, Lennart
    et al.
    Arvidsson, BjörnKarlstad University, Faculty of Social and Life Sciences, Department of Biology.Österling, MartinKarlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Aquatic Conservation with Focus on Margaritifera margaritifera: Proceedings of the International Conference in Sundsvall, Sweden, 12-14 August, 20092012Conference proceedings (editor) (Other academic)
    Abstract [en]

    The freshwater pearl mussel Margaritifera margaritifera (L.) has attracted a large human interest, since the mussel is fascinating from biological, cultural andenvironmental perspectives. The mussel has a complicated life cycle dependingon host fish, and has great demands on its habitat. Furthermore, the mussel is anenvironmental indicator, and is used as an umbrella and flagship species. Pearl fishing has been described in Sweden as early as in the 16th century and by Carl Linnaeus in the 18th century.

    Many freshwater pearl mussel populations have insufficient recruitment and therefore decrease in numbers, and many populations are even extinct. Therefore, conservation work on the freshwater pearl mussel is going on all over Europe. Actions to preserve the freshwater pearl mussel will also favour other aquatic species – freshwater pearl mussel conservation is aquatic biodiversity conservation! WWF (World Wide Fund for Nature) Sweden implemented the project “The Freshwater Pearl Mussel and its habitats in Sweden” during 2004-2009 (LIFE04NAT/SE/000231). The overall objective was to improve the habitats of juvenile freshwater pearl mussels and the host fish brown trout Salmo trutta in21 streams. The actions were improvements of the biotopes, re-introduction of mussels, information to the stakeholders, and development of planning methods. An international conference “Aquatic Conservation with Focus on the Freshwater Pearl Mussel Margaritifera margaritifera” was held in Sundsvall 12–14 August, 2009. In these proceedings, presentations from the conference are published.

  • 72.
    Herstad, Sverre J.
    et al.
    University Oslo, Norway.
    Solheim, Marte C. W.
    University Stavanger, Norway.
    Engen, Marit
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Service Research Center (from 2013).
    Learning through urban labour pools: Collected worker experiences and innovation in services2019In: Environment and planning A, ISSN 0308-518X, E-ISSN 1472-3409, Vol. 51, no 8, p. 1720-1740, article id UNSP 0308518X19865550Article in journal (Refereed)
    Abstract [en]

    Knowledge-intensive services firms depend on the skills and networks of employees and tend to cluster in large-city regions. This raises the fundamental question of whether knowledge-intensive services firms 'learn through urban labour pools' in manners that have implications for innovation. To address it, a distinction is in this paper made between 'related variety' and 'unrelated variety' of work-life experiences collected by employees and combined in firms. The empirical analysis uses innovation survey and register data to demonstrate that higher levels of unrelated variety among staff in urban knowledge-intensive services firms inspire innovation activity and increase the probability of innovation success. Outside cities, where knowledge-intensive services firms on average have more specialized knowledge bases, innovation responds negatively to unrelated variety and positively to related variety. As a result, the sign, size and significance of urban-rural dividing lines in innovation propensities depend on whether firms have cultivated the skill profiles that are most conducive to innovation in their locations. Constraints faced specifically by knowledge-intensive services firms outside cities in this respect are identified and implications for policy drawn.

  • 73.
    Hintz, William D.
    et al.
    Rensselaer Polytech Inst, Darrin Fresh Water Inst, Dept Biol Sci, 110 8th St, Rensselaer, NY 12180 USA..
    Mattes, Brian M.
    Rensselaer Polytech Inst, Darrin Fresh Water Inst, Dept Biol Sci, 110 8th St, Rensselaer, NY 12180 USA..
    Schuler, Matthew S.
    Rensselaer Polytech Inst, Darrin Fresh Water Inst, Dept Biol Sci, 110 8th St, Rensselaer, NY 12180 USA..
    Jones, Devin K.
    Rensselaer Polytech Inst, Darrin Fresh Water Inst, Dept Biol Sci, 110 8th St, Rensselaer, NY 12180 USA..
    Stoler, Aaron B.
    Rensselaer Polytech Inst, Darrin Fresh Water Inst, Dept Biol Sci, 110 8th St, Rensselaer, NY 12180 USA..
    Lind, Lovisa
    Rensselaer Polytech Inst, Darrin Fresh Water Inst, Dept Biol Sci, 110 8th St, Rensselaer, NY 12180 USA..
    Relyea, Rick A.
    Rensselaer Polytech Inst, Darrin Fresh Water Inst, Dept Biol Sci, 110 8th St, Rensselaer, NY 12180 USA..
    Salinization triggers a trophic cascade in experimental freshwater communities with varying food-chain length2017In: Ecological Applications, ISSN 1051-0761, E-ISSN 1939-5582, Vol. 27, no 3, p. 833-844Article in journal (Refereed)
    Abstract [en]

    The application of road deicing salts in northern regions worldwide is changing the chemical environment of freshwater ecosystems. Chloride levels in many lakes, streams, and wetlands exceed the chronic and acute thresholds established by the United States and Canada for the protection of freshwater biota. Few studies have identified the impacts of deicing salts in stream and wetland communities and none have examined impacts in lake communities. We tested how relevant concentrations of road salt (15, 100, 250, 500, and 1000mgCl(-)/L) interacted with experimental communities containing two or three trophic levels (i.e., no fish vs. predatory fish). We hypothesized that road salt and fish would have a negative synergistic effect on zooplankton, which would then induce a trophic cascade. We tested this hypothesis in outdoor mesocosms containing filamentous algae, periphyton, phytoplankton, zooplankton, several macroinvertebrate species, and fish. We found that the presence of fish and high salt had a negative synergistic effect on the zooplankton community, which in turn caused an increase in phytoplankton. Contributing to the magnitude of this trophic cascade was a direct positive effect of high salinity on phytoplankton abundance. Cascading effects were limited with respect to impacts on the benthic food web. Periphyton and snail grazers were unaffected by the salt-induced trophic cascade, but the biomass of filamentous algae decreased as a result of competition with phytoplankton for light or nutrients. We also found direct negative effects of high salinity on the biomass of filamentous algae and amphipods (Hyalella azteca) and the mortality of banded mystery snails (Viviparus georgianus) and fingernail clams (Sphaerium simile). Clam mortality was dependent on the presence of fish, suggesting a non-consumptive interactive effect with salt. Our results indicate that globally increasing concentrations of road salt can alter community structure via both direct and indirect effects.

  • 74.
    Hulthen, K.
    et al.
    Lund University.
    Chapman, B. B.
    Lund University.
    Nilsson, Per Anders
    Lund University.
    Hansson, L. -A
    Lund University.
    Skov, C.
    Danmark.
    Baktoft, H.
    Danmark.
    Brodersen, J.
    Switzerland.
    Bronmark, C.
    Lund University.
    Sex identification and PIT-tagging: tools and prospects for studying intersexual differences in freshwater fishes2014In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 84, no 2, p. 503-512Article in journal (Refereed)
  • 75.
    Hulthen, Kaj
    et al.
    Lund University, Sweden.
    Chapman, Ben B.
    Lund University, Sweden.
    Nilsson, P. Anders
    Lund University, Sweden.
    Hollander, Johan
    Lund University, Sweden.
    Bronmark, Christer
    Lund University, Sweden.
    Express yourself: bold individuals induce enhanced morphological defences2014In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 281, no 1776, p. 20132703-Article in journal (Refereed)
    Abstract [en]

    Organisms display an impressive array of defence strategies in nature. Inducible defences (changes in morphology and/or behaviour within a prey's lifetime) allow prey to decrease vulnerability to predators and avoid unnecessary costs of expression. Many studies report considerable interindividual variation in the degree to which inducible defences are expressed, yet what underlies this variation is poorly understood. Here, we show that individuals differing in a key personality trait also differ in the magnitude of morphological defence expression. Crucian carp showing risky behaviours (bold individuals) expressed a significantly greater morphological defence response when exposed to a natural enemy when compared with shy individuals. Furthermore, we show that fish of different personality types differ in their behavioural plasticity, with shy fish exhibiting greater absolute plasticity than bold fish. Our data suggest that individuals with bold personalities may be able to compensate for their risk-prone behavioural type by expressing enhanced morphological defences.

  • 76. Hulthén, K.
    et al.
    Chapman, B.B.
    Nilsson, Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Vinterstare, J.
    Hansson, L-A.
    Skov, C.
    Brodersen, J.
    Baktoft, H.
    Brönmark, C.
    Escaping peril: perceived predation risk affects migratory propensity2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, article id 20150466Article in journal (Refereed)
  • 77.
    Hutchings, Jeffrey A.
    Dalhousie University, Canada; Flødevigen Marine Research Station, Norway; University of Agder, Norway.
    Barlaup, Björn T
    Norwegian Research Centre, Norway.
    Bergman, Eva
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Clarke, Keith D.
    Fisheries and Oceans Canad, Canada.
    Greenberg, Larry
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Lake, Colin
    Glenora Fisheries Station, Canada.
    Piironen, Jorma
    Natural Resources Institute Finland (Luke), Finland.
    Sirois, Pascal
    Université du Québec à Chicoutimi, Canada.
    Sundt-Hansen, Line E
    Université du Québec à Chicoutimi, Canada.
    Fraser, Dylan J.
    Concordia University, Canada.
    Life-history variability and conservation status of landlocked Atlantic salmon: an overview2019In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 76, no 10, p. 1697-1708Article in journal (Refereed)
    Abstract [en]

    Nonanadromous Atlantic salmon (Salmo salar) exhibit a combination of variation in life history, habitat, and species co-existence matched by few vertebrates. Distributed in eastern North America and northern Europe, habitat ranges from hundreds of metres of river to Europe’s largest lakes. As juveniles, those with access to a lake usually migrate to feed and grow prior to reproduction. Prey such as smelt (Osmerus mordax, Osmerus eperlanus) and vendace (Coregonus albula) facilitate large body size (50–85 cm at maturity) and persistence in high-diversity (>20 fish species) environments; small-bodied salmon (10–30 cm at maturity), relying on insects as prey, coexist with few (fewer than five) other fishes. At maturity, weight varies more than 400-fold (17 to 7200 g) among populations, fecundity more than 150-fold (33 to 5600), and longevity almost fivefold (3 to 14 years). Landlocked salmon are managed to support sustainable fishing, achieve conservation and restoration targets, and mitigate threats; successes are evident but multiple challenges persist. Extraordinary variability in life history coupled with extensive breadth of habitat and species co-existence render landlocked Atlantic salmon singularly impressive from a biodiversity perspective.

  • 78.
    Jakubowski, Patrik
    Karlstad University.
    Halogen och LED påverkar tillväxt och fotosyntetisk aktivitet olika hos manetarten Cassiopeia sp.2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The jellyfish, Cassiopeia sp, maintain zooxanthellae symbionts in their tissue, which provide the jellyfish with photosynthetic products that are used for growth. In this study I investigated how halogen and LED lamps at two intensities influence the photosynthetic activity of these symbionts differently, and if growth differences between the jellyfishes were affected by lamp type. The experiment was running for 4 weeks and the results showed greater growth in the halogen groups at both intensity classes. Phosphate reduction in the surrounding water and oxygen production was used as a measure of photosynthetic activity, where oxygen production was higher in both groups of halogen compared to the LED groups. The phosphate test of the jellyfishes ambient water showed no significant differens depending on halogen and LED, but was depended on light intensity, where the individuals in the higher intensity classes assimilated greater amounts of phosphate. Overall, the study shows a difference between the lamp types where halogen results in greater photosynthetic activity by the symbionts than in the LED groups, which leads to greater growth measured as bell diameter. 

  • 79.
    Johansson, Patricia
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Evertebraters kolonisation på fin ved i semi-naturliga bäckar2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wood can be added to streams to create microhabitats that provide macroinvertebrates with an opportunity for re-colonization by making the stream more heterogeneous. I examined colonization on wood substrate by macroinvertebrates in semi-natural streams in northern Finland during a three month period. Each of the streams was divided in three sections A, B and C, half of which were provided with wood. The focus has been on whether the density of macroinvertebrates changes with time, along an upstream-downstream direction in the streams, or in streams with two wood sections if macroinvertebrates will colonize the first section with wood that they come in contact with (upstream section) or if they continue downstream to the second section with wood. Wood from Salix sp. was placed in nine of the 18 enclosures during mid-June. Samples of wood were removed from the streams on three different occasions from August to October 2014. A total of 32 taxa were identified from the wood and assigned to functional feeding groups: shredders, scrapers, active filter feeders, passive filter feeders, collectors, miners, piercers and predators. The results showed that collectors, miners and piercers increased in density during the month of October and the abundance of scrapers was higher in the upstream location than in the downstream location. Total number of macroinvertebrates, collectors, passive filter feeders and predators had a higher colonization on the first substrate they came into contact with.

  • 80.
    Jones, Devin K.
    et al.
    Rensselaer Polytech Inst, Dept Biol Sci, Troy, NY 12180 USA..
    Mattes, Brian M.
    Rensselaer Polytech Inst, Dept Biol Sci, Troy, NY 12180 USA..
    Hintz, William D.
    Rensselaer Polytech Inst, Dept Biol Sci, Troy, NY 12180 USA..
    Schuler, Matthew S.
    Rensselaer Polytech Inst, Dept Biol Sci, Troy, NY 12180 USA..
    Stoler, Aaron B.
    Rensselaer Polytech Inst, Dept Biol Sci, Troy, NY 12180 USA..
    Lind, Lovisa
    Rensselaer Polytech Inst, Dept Biol Sci, Troy, NY 12180 USA..
    Cooper, Reilly O.
    Rensselaer Polytech Inst, Dept Biol Sci, Troy, NY 12180 USA..
    Relyea, Rick A.
    Rensselaer Polytech Inst, Dept Biol Sci, Troy, NY 12180 USA..
    Investigation of road salts and biotic stressors on freshwater wetland communities2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 221, p. 159-167Article in journal (Refereed)
    Abstract [en]

    The application of road deicing salts has led to the salinization of freshwater ecosystems in northern regions worldwide. Increased chloride concentrations in lakes, streams, ponds, and wetlands may negatively affect freshwater biota, potentially threatening ecosystem services. In an effort to reduce the effects of road salt, operators have increased the use of salt alternatives, yet we lack an understanding of how these deicers affect aquatic communities. We examined the direct and indirect effects of the most commonly used road salt (NaCl) and a proprietary salt mixture (NaCl, KCl, MgCl2), at three environmentally relevant concentrations (150, 470, and 780 mg Cl-/L) on freshwater wetland communities in combination with one of three biotic stressors (control, predator cues, and competitors). The communities contained periphyton, phytoplankton, zooplankton, and two tadpole species (American toads, Anaxyrus americanus; wood frogs, Lithobates sylvaticus). Overall, we found the two road salts did not interact with the natural stressors. Both salts decreased pH and reduced zooplankton abundance. The strong decrease in zooplankton abundance in the highest NaCl concentration caused a trophic cascade that resulted in increased phytoplankton abundance. The highest NaCl concentration also reduced toad activity. For the biotic stressors, predatory stress decreased whereas competitive stress increased the activity of both tadpole species. Wood frog survival, time to metamorphosis, and mass at metamorphosis all decreased under competitive stress whereas toad time to metamorphosis increased and mass at metamorphosis decreased. Road salts and biotic stressors can both affect freshwater communities, but their effects are not interactive. (C) 2016 Elsevier Ltd. All rights reserved.

  • 81.
    Jonsson, Simon
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Identifiering av lek- och övervintringsområden för lax (Salmo salar) och öring (Salmo trutta) i Klarälven2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 82.
    Kaiskog, Frida
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Rörelsemönster hos öring (Salmo trutta): En jämförelse mellan vilda och odlade individer i sjön Siljan2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Many populations of salmonids are threatened by fragmentation and degradation of spawning habitats. Common remedial measures are habitat restoration and stocking of hatchery fish to support degraded wild populations. Many populations of brown trout in Sweden have been extirpated. The restoration plan for the endangered brown trout in Lake Siljan started decades ago and involves releases of hatchery produced trout. A decline of the spawning run of hatchery fish has been observed. In this study, wild and hatchery fish were tagged and monitored using hydroacustic telemetry during May-October, 2018. Movement patterns were studied to detect potential differences between wild and hatchery fish during lake and spawning migration. The results showed a difference of preferred territories between the groups. The wild trout stayed in the northern part of the lake and the hatchery trout were more evenly distributed over the lake, but with a preference for the southern part of the lake. During spawning migration a larger proportion of the wild trout (44 %) moved to potential spawning habitats as compared to hatchery trout (16 %). The wild fish migrated more or less direct to the potential spawning grounds in River Österdal as compared to the hatchery fish, which showed an erratic behavior and preferred to migrate to the tributaries in Lake Siljan. Differences in movement patterns and preferred habitats in the lake can be caused by differences in behavior between the groups. This should motivate more studies of behavior of wild and hatchery trout. The time for spawning and potential spawning habitats are also important to study for future management and restoration of the wild population of brown trout in Lake Siljan.

  • 83.
    Karlsson, P S
    et al.
    Uppsala University.
    Eckstein, Rolf Lutz
    Uppsala University.
    Weih, M
    Uppsala University.
    Seasonal variation in N-15 natural abundance in subarctic plants of different life-forms2000In: Ecoscience, ISSN 1195-6860, Vol. 7, no 3, p. 365-369Article in journal (Refereed)
  • 84.
    Klenz, Martin
    Karlstad University, Faculty of Social and Life Sciences.
    Tidsanvändandet hos den svartvita stenskvättan (Oenanthe alboniger)2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Between Feb. 1st and Feb. 9th 2011, 23 different individuals of Hume´s Wheatear (Oenanthealboniger) with unspecified gender were observed in the area of the Hajjar– Mountains in the United Arab Emirates (UAE). The observed behavior was registered referring to seven pre-defined behavioral categories (Flying,chasing, singing, handling prey, nest-building, perching and preening) together with measurements of air-temperature (°C) and luminance (lux). The observed individuals spend on average 68,5 % of their time on perching, 12,6 % on handling prey, 10,3 % on flying, 6,1 % on singing and 2,5 % on preening, while categories “nest-building” and “chasing” did not occur once. Statistical analyses of the observation frequencies indicate that there is no significant difference between individuals; a very strong significant difference between category frequencies could be shown by the use of a one-factor analysis of variances (ANOVA). A correlation analysis of changes in temperature or luminance and frequency of shown behavior presented no existing relationship between measured environmental factors and behavior within the measured ranges and time-frame.

  • 85.
    Kopnina, Helen
    et al.
    Leiden University, The Netherlands.
    Washington, Haydn
    The University of New South Wales, Australia.
    Taylor, Bron
    University of Florida, USA; Ludwig Maximillian University of Munich, Germany.
    Piccolo, John
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Anthropocentrism: More than just a misunderstood problem2018In: Journal of Agricultural and Environmental Ethics, ISSN 1187-7863, E-ISSN 1573-322X, Vol. 31, no 1, p. 109-127Article in journal (Refereed)
    Abstract [en]

    Anthropocentrism, in its original connotation in environmental ethics, is the belief that value is human-centred and that all other beings are means to human ends. Environmentally -concerned authors have argued that anthropocentrism is ethically wrong and at the root of ecological crises. Some environmental ethicists argue, however, that critics of anthropocentrism are misguided or even misanthropic. They contend: first that criticism of anthropocentrism can be counterproductive and misleading by failing to distinguish between legitimate and illegitimate human interests. Second, that humans differ greatly in their environmental impacts, and consequently, addressing human inequalities should be a precondition for environmental protection. Third, since ecosystems constitute the "life-support system" for humans, anthropocentrism can and should be a powerful motivation for environmental protection. Fourth, human self-love is not only natural but helpful as a starting point for loving others, including nonhumans. Herein we analyze such arguments, agreeing with parts of them while advancing four counter-arguments. First, redefining the term anthropocentrism seems to be an attempt to ignore behavior in which humans focus on themselves at the risk of the planet. Second, if addressing human inequalities is a precondition for environmental protection, biodiversity protection will remain out of the scope of ethical consideration for an indefinite period of time. Third, anthropocentric motivations can only make a positive contribution to the environment in situations where humans are conscious of a direct benefit to themselves. Fourth, 'self-love' alone is an inadequate basis for environmental concern and action. We also explore the question of agency, shared responsibility, and a fair attribution of blame for our environmental predicaments.

  • 86.
    Krange, Maria
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Change in the occurrence of the West European Hedgehog (Erinaceus europaeus) in western Sweden during 1950-2010.2015Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Hedgehog populations have declined all over Europe.  Here I describe population trends in three west Swedish counties, based on questionnaire surveys and interviews conducted in 1993 and 2010. I found that people questioned in 1993 had more recently seen hedgehogs than people asked in 2010, which indicates the hedgehog population has declined.  One of reasons for this decline may be the presence of badgers, as the occurrence of hedgehogs was inversely related to the presence of badgers. There was no difference in where hedgehog sightings occurred; sightings were equally likely to occur in suburban/urban areas as in rural areas, despite previous studies in Sweden and western Europe reporting a higher occurrence in suburban/urban areas.

  • 87.
    Lafage, Denis
    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).
    Eckstein, Rolf Lutz
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Österling, Martin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Sadler, J. P.
    University of Birmingham.
    Piccolo, John
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Local and landscape drivers of aquatic-to-terrestrial subsidies in riparian ecosystems: A worldwide meta-analysis2019In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 10, no 4, p. 1-12, article id e02697Article in journal (Refereed)
    Abstract [en]

    Cross-boundary fluxes of organisms and matter, termed “subsidies,” are now recognized to be reciprocal and of roughly equal importance for both aquatic and terrestrial systems, even if terrestrial input to aquatic ecosystems has received most attention. The magnitude of aquatic-to-terrestrial subsidies is well documented, but the drivers behind these subsidies and their utilization by terrestrial consumers are characteristically local-scale studies, limiting the inferences that can be drawn for broader geographic scales. We therefore built and analyzed a database of stable isotope data extracted from 21 studies worldwide, to identify both landscape-scale (catchment) and local-scale (100-m riparian zone) variables that may affect the diet of terrestrial predators in riparian ecosystems. Our meta-analysis revealed a greater magnitude of aquatic-to-terrestrial subsidies (>50%) than previously reported, albeit with large geographic and inter-annual variations. Moreover, we demonstrated a large effect of landscape-scale factors on aquatic-to-terrestrial subsidies, particularly anthropogenic land use and tree cover. Local human population was the only relevant factor at the local scale. We also found that studies on landscape-scale and anthropogenic land use effects on aquatic-to-terrestrial subsidies are strongly under-represented in the ecological literature, which limits the general inferences that can currently be drawn about landscape effects. We suggest that landscape-scale studies could improve our understanding of how land use and environmental change might influence future patterns of biodiversity and ecosystem function.

  • 88.
    Lafage, Denis
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Djoudi, El Aziz
    Université de Rennes, France.
    Perrin, Gwenhaël
    Université de Bretagne Occidentale, France.
    Gallet, Sèbastien
    Université de Bretagne Occidentale, France.
    Pétillon, Julien
    Université de Rennes, France.
    Responses of ground-dwelling spider assemblages to changes in vegetation from wet oligotrophic habitats of Western France2019In: Arthropod-Plant Interactions, ISSN 1872-8855, E-ISSN 1872-8847, Vol. 13, no 4, p. 653-662Article in journal (Refereed)
    Abstract [en]

    While many arthropod species are known to depend, directly or indirectly, on certain plant species or communities, it remains unclear to what extent vegetation shapes spider assemblages. In this study, we tested whether the activity-density, composition, and diversity of ground-dwelling spiders were driven by changes in vegetation structure. Field sampling was conducted using pitfall traps in bogs, heathlands, and grasslands of Brittany (Western France) in 2013. A total of 8576 spider individuals were identified up to the species level (for a total of 141 species), as well as all plant species in more than 300 phytosociological relevés. A generalised linear model showed that spider activity-density was negatively influenced by mean vegetation height and mean Ellenberg value for moisture. Indices of diversity (ɑ, β, and functional diversities) increased with increasing vegetation height and shrub cover. Variables driving spider composition were mean vegetation height, dwarf shrub cover, and low shrub cover (results from a redundancy analysis). Spiders, some of the most abundant arthropod predators, are thus strongly influenced by vegetation structure, including ground-dwelling species. Although later successional states are usually seen as detrimental to local biodiversity in Europe, our results suggest that allowing controlled development of the shrub layer could have a positive impact on the diversity of ground-dwelling spiders. 

  • 89.
    Lafage, Denis
    et al.
    France.
    Maugenest, Sebastien
    Bouzille, Jan-Bernard
    Petillon, Julien
    Disentangling the influence of local and landscape factors on alpha and beta diversities: opposite response of plants and ground-dwelling arthropods in wet meadows2015In: Ecological research, ISSN 0912-3814, E-ISSN 1440-1703, Vol. 30, no 6, p. 1025-1035Article in journal (Refereed)
    Abstract [en]

    A large number of studies have tried to understand the determinants of local species richness, i.e. alpha-diversity. Studies dealing with beta-diversity are considerably less numerous but their number has increased in the recent years. In this study, we assessed the relative importance of local and landscape (i.e. composition and connectivity) variables in explaining alpha- and beta-diversities (species turnover and nestedness) of three highly diverse groups, differing in mobility and dispersal: plants, spiders, and carabids. Sampling took place in 2013, using suction samplers for arthropods and phytosociological relev,s for vegetation, in 77 hay meadows distributed along 200 km of the Loire Valley (France). We found plant alpha-diversity to be driven by local factors, whereas spider and carabid alpha-diversities were mostly determined by landscape factors (by composition and connectivity, respectively). Nestedness was negligible for the three groups. Plant beta-diversity was also mainly influenced by local factors, whereas spider beta-diversity was driven by landscape factors (composition and connectivity, equally). Surprisingly, carabid beta-diversity was mainly influenced by local factors and landscape connectivity. Despite these differences, plant, spider, and carabid beta-diversities were not different, suggesting comparable dispersal abilities and/or a low connectivity at large scale, which is in accordance with the high species turnover observed here. Managing biodiversity in meadows consequently necessitates acting at local and landscape scales, the first targeting plants and the second arthropods.

  • 90.
    Lafage, Denis
    et al.
    University Rennes, University Angers, France.
    Petillon, Julien
    University Rennes, France.
    Relative importance of management and natural flooding on spider, carabid and plant assemblages in extensively used grasslands along the Loire2016In: Basic and Applied Ecology, ISSN 1439-1791, E-ISSN 1618-0089, Vol. 17, no 6, p. 535-545Article in journal (Refereed)
    Abstract [en]

    In Europe, agri-environment schemes (ALS) have been implemented to counteract the effects of agricultural intensification. Studies investigating the role of management improvement induced by AES are quite numerous, but rarely take into account the effect of natural perturbations such as flooding, although severe disturbances are well known to shape community structure, Here we investigated the relative importance of management improvement and flooding to explain community parameters of two dominant arthropod groups and vegetation in alluvial meadows. Sampling took place in 2013, using suction samplers for arthropods and phytosociological releves for vegetation, in 83 meadows distributed along 200 km of the Loire Valley (France). Pair-matched approach (by R-ANOVA) was used to assess overall effects of AES whereas a gradient analysis (GLM) was carried out to assess the impact of AES prescriptions (fertilisation and cutting-date) together with indirect (long-term) and direct (short-term) effects of flooding. No significant effect of AES was found on arthropod and plant assemblages, abundance/productivity or diversity (both alpha and beta), but the number of rare plant species was higher in sites under AES. Prescriptions had little impact on most response variables considered; the only significant impact being the positive effect of high-amounts of fertilisers on spider alpha- and beta-diversities, Conversely, systematic long-term effects of flooding were found on all response variables of spiders, carabids and plants, underlining the key role of this factor in alluvial meadows, Our study demonstrates that maintaining or enhancing hydrological functioning of ecosystems is even more important than regulating both the cutting-dates and the low input of fertilisers for conservation purposes in flooded, already naturally nutrient rich, meadows.

  • 91.
    Lafage, Denis
    et al.
    France.
    Sibelle, Charlotte
    Université d'Angers, France.
    Secondi, Jean
    Université d'Angers, France.
    Canard, Alain
    Université de Rennes 1, France.
    Petillon, Julien
    Université de Rennes 1, France.
    Short-term resilience of arthropod assemblages after spring flood, with focus on spiders (Arachnida Araneae) and carabids (Coleoptera: Carabidae)2015In: Ecohydrology, ISSN 1936-0584, E-ISSN 1936-0592, Vol. 8, no 8, p. 1584-1599Article in journal (Refereed)
    Abstract [en]

    Despite the expected increase in extreme flood frequency, the manner in which terrestrial arthropods cope with regular submersion of their habitat remains poorly understood in meadows, especially in temperate floodplains. Here, we studied the recolonization dynamics of arthropods after a severe spring flood in the Loire Valley (France). We carried out analyses at the community (order or family identification level) and species scales, focusing on the assemblages of two dominant and diverse groups: carabids and spiders. Our objectives were the following: (i) to describe the temporal changes in community structure after flooding and (ii) to assess the influence of landscape configuration on recolonization patterns of species and their functional traits. Fieldwork was performed along three sampling transects, by using 75 pitfall traps, in 2012. A total of 14767 arthropods belonging to 87 families were trapped, including 5538 spiders (55 species) and 3396 carabids (66 species). Multivariate analyses discriminated assemblages from flooded and non-flooded habitats and revealed changes over time in arthropod families and species after flood withdrawal. In particular, wolf spiders (Lycosidae) were the first to recolonize, whereas other groups clearly avoided flooded sites. Our results also revealed that short distances to hedgerows, and to a lesser extent, distance to woodlands, favoured the recolonization of large and ground-running spiders. In conclusion, our study shows the short-term resilience of certain groups or stenotopic species to flooding and also the relevance of multi-taxon-based studies. The presence of hedgerows has to be considered carefully in management plans because of their role of refuge during flooding. Copyright (c) 2015 John Wiley & Sons, Ltd.

  • 92.
    Lans, Linnea
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Relations between metabolic rate, migration and behaviour in Atlantic salmon (Salmo salar) and brown trout (Salmo trutta)2010Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

     

    ABSTRACT

     

    Migration is common among populations of brown trout (Salmo trutta) and Atlantic salmon (Salmo salar). However, not all individuals in the same population migrate, a phenomenon referred to as partial migration. The aim of this thesis was to investigate if an individual’s behaviour and metabolic rate influences its decision to migrate and how such knowledge may be used when trying to produce hatchery-raised smolts with as high a proportion of migrating individuals as possible. In paper I the influence of reduced food ration on the proportion and swimming speed of migrating brown trout and Atlantic salmon smolts was investigated. Furthermore, the standard metabolic rate (SMR) of migrating and non-migrating individuals was compared. In paper II, a laboratory experiment, SMR was correlated to the behaviour of individual brown trout and Atlantic salmon. Dominant fish of both species had a higher SMR than subordinates (paper II). In addition, migrant brown trout had a higher SMR than non-migrant trout when given a normal food ration, whereas no difference in SMR between migrating and non-migrating salmon could be seen (paper I). When administered low food rations, smolts of both species migrated faster than smolts given a normal food ration, and the proportion of migrating smolts was higher for salmon given less food when the size difference for smolts from the two feeding regimes was large (paper I). Other factors that influenced migration speed were the degree of smolt development and water temperature (paper I). SMR was not correlated with aggressiveness, or with different measurements of boldness. Moreover, aggression and boldness were not correlated with each other (paper II). Trout showed a higher level of aggressiveness and acclimated more rapidly to laboratory conditions than salmon (paper II). In summary, there was no support for the existence of coping styles in migratory Atlantic salmon and brown trout. Instead, metabolic rates were related to both migratory behaviour and social status. Furthermore, an individual’s decision to migrate was influenced by ration size.

  • 93.
    Lans, Linnea
    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.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Individual variation in behaviour and metabolic rates of brown trout (Salmo trutta) and Atlantic salmon (Salmo salar): evidence for coping styles?Manuscript (preprint) (Other academic)
    Abstract [en]

    Previous studies have suggested that there may be coping styles in salmonids, which may correspond with the decision to migrate or remain resident. Two types of coping styles have been described, a proactive one, where individuals are aggressive, bold and have a high metabolic rate and a reactive one, where individuals are less aggressive and bold, more flexible and have a lower metabolic rate. The aim of this study was to examine if coping styles could be identified in Atlantic salmon (Salmo salar), a species where nearly all individuals migrate and brown trout (Salmo trutta), a species that exhibits partial migration. No correlations between boldness, aggressiveness, standard metabolic rate (SMR) and dominance could be found in either species, which indicates that stress-related coping styles did not exist in the hatchery-reared fish used. However, dominant individuals of both species had a higher SMR than their subordinate conspecifics. Furthermore, the brown trout in this experiment were more aggressive and formed dominance relationships more rapidly than Atlantic salmon. The trout also initiated feeding faster when introduced into a new environment.

  • 94.
    Lans, Linnea
    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.
    Karlsson, Jens
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Calles, Olle
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Schmitz, Monika
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Bergman, Eva
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    The effects of ration size on migration by hatchery-raised Atlantic salmon (Salmo salar) and brown trout (Salmo trutta)2011In: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, Vol. 20, no 4, p. 548-557Article in journal (Refereed)
    Abstract [en]

    The possibility to increase the proportion of migrating hatchery-reared smolts by reducing their food ration was studied. Lake-migrating, hatchery-reared salmon (Salmo salar) and trout (Salmo trutta) smolts were either fed normal rations, based on recommendations from the fish-farming industry, or reduced (15–20%) rations. They were released into the River Klarälven, western Sweden, and followed as they swam downstream to Lake Vänern, a distance of around 25 km. For both Atlantic salmon and brown trout, smolts fed a reduced ration migrated faster than fish fed a normal ration. Furthermore, a higher proportion of salmon smolts fed reduced rations migrated to the lake than fish fed normal rations in 2007 but not in 2006. This difference between years corresponded to greater treatment differences in size and smolt status in 2007 than in 2006. For trout, the proportion of migrating individuals and smolt development did not differ with ration size. Trout migrants fed a normal ration had a higher standard metabolic rate (SMR) than nonmigrants, whereas there was no difference in SMR between migrating and nonmigrating salmon. These results show that it is possible to use a reduced food ration to increase the migration speed of both Atlantic salmon and brown trout and to increase the proportion of migrating Atlantic salmon.

  • 95.
    Lee, Marcus
    et al.
    Lund University, Sweden.
    Zhang, Huan
    Lund University, Sweden ; Chinese Academy of Sciences, China.
    Sha, Yongcui
    Lund University, Sweden.
    Hegg, Alexander
    Lund University, Sweden.
    Ugge, Gustaf Ekelund
    Lund University, Sweden.
    Vinterstare, Jerker
    Lund University, Sweden.
    Skerlep, Martin
    Lund University, Sweden.
    Parssinen, Varpu
    Lund University, Sweden.
    Herzog, Simon David
    Lund University, Sweden.
    Bjorneras, Caroline
    Lund University, Sweden.
    Gollnisch, Raphael
    Lund University, Sweden.
    Johansson, Emma
    Lund University, Sweden.
    Hu, Nan
    Lund University, Sweden.
    Nilsson, Per Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013). Lund University, Sweden.
    Hulthen, Kaj
    Lund University, Sweden ; North Carolina State University, USA.
    Rengefors, Karin
    Lund University, Sweden.
    Langerhans, R. Brian
    North Carolina State University, USA ; North Carolina State University, USA.
    Bronmark, Christer
    Lund University, Sweden.
    Hansson, Lars-Anders
    Lund University, Sweden.
    Low-latitude zooplankton pigmentation plasticity in response to multiple threats2019In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 7, p. 1-10, article id 190321Article in journal (Refereed)
    Abstract [en]

    Crustacean copepods in high-latitude lakes frequently alter their pigmentation facultatively to defend themselves against prevailing threats, such as solar ultraviolet radiation ( UVR) and visually oriented predators. Strong seasonality in those environments promotes phenotypic plasticity. To date, no one has investigated whether low-latitude copepods, experiencing continuous stress from UVR and predation threats, exhibit similar inducible defences. We here investigated the pigmentation levels of Bahamian 'blue hole' copepods, addressing this deficit. Examining several populations varying in predation risk, we found the lowest levels of pigmentation in the population experiencing the highest predation pressure. In a laboratory experiment, we found that, in contrast with our predictions, copepods from these relatively constant environments did show some changes in pigmentation subsequent to the removal of UVR; however, exposure to water from different predation regimes induced minor and idiosyncratic pigmentation change. Our findings suggest that low-latitude zooplankton in inland environments may exhibit reduced, but non-zero, levels of phenotypic plasticity compared with their high-latitude counterparts.

  • 96.
    Lilja, Joakim
    Karlstad University, Faculty of Social and Life Sciences.
    Kan nedbrytning av drunknade älgarpåverka ett vattendrags näringsbudget?2009Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]
    • Energiflöden mellan terrestra och akvatiska ekosystem har uppmärksammats mycket den senaste tiden. I den här studien undersöker jag betydelsen av ett terrestert djur, älgen (Alces alces), som dör i vattendrag och avger näring till vattnet. Genom litteraturstudier och teoretiska beräkningar uppskattade jag hur vanligt det är att älgar dör i vattendrag och om dessa älgar har någon inverkan på vattendragets totala näringsbudget. Jag fann att drunkning hos älgar tas upp som en parameter för naturliga dödsorsaker i flera artiklar från USA, Canada och Polen. Orsakerna till att älgar drunknar, trots att de är duktiga simmare, kan vara t.ex. att stranden är för brant, att de tvingas ner i vattnet av rovdjur, att skadeskjutna älgar söker sig till vatten på grund av törstkänningar i samband med blodförlust eller att de går igenom svaga isar. Utifrån teoretiska beräkningar fann jag även att en älg som dött i ett vattendrag bidrar till mycket liten del av den totala näringsbudgeten. Min hypotes är att det endast blir en lokal påverkan nedströms djuret. Hur denna påverkan ser ut och om den kommer primärproducenter och fiskar tillgodo är mycket komplext och undersöks inte i denna studie.
  • 97.
    Lind, Lovisa
    et al.
    Umeå University, Umeå, Sweden.
    Alfredsen, Knut
    University of Science and Technology, 7491 Trondheim, Norway.
    Kuglerova, Lenka
    University of British Columbia, V6T 1Z4 Vancouver, Canada.
    Nilsson, Christer
    Umeå University, Umeå, Sweden.
    Hydrological and thermal controls of ice formation in 25 boreal stream reaches2016In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 540, p. 797-811Article in journal (Refereed)
    Abstract [en]

    The Northern Hemisphere has a high density of fluvial freshwater ecosystems, many of which become ice-covered during winter. The development and extent of ice have both ecological and socio-economic implications. For example, ice can cause freezing of riparian vegetation and fish eggs as well as influence hydropower production; however, when, where and why ice develops in small streams is not well known. We used observations from 25 stream reaches to study the factors controlling ice development during two consecutive winters, addressing where in the catchment surface or anchor-ice is most likely to develop, how stream morphology influences ice formation, and how climate influences ice processes. Reaches far downstream from lake outlets, or without any upstream lakes, were most prone to develop anchor-ice, but other factors also influenced ice formation. Anchor-ice was most common where water temperature and groundwater inputs were low and stream power high. Given cold air temperature and water supercooling, the in-stream substrate as well as the current velocity were also important for the development of anchor-ice. Climate and substrate seemed to be important factors for the development of surface ice. This study shows that ice processes are substantial during the hydrological year and may therefore have large implications for the ecology and engineering around boreal streams.. The study also demonstrates that ice formation in the studied streams was complex, involving many variables and physical processes. We constructed a conceptual model describing the likelihood for various ice types to develop, based on the large dataset. As such, this model will be useful for practitioners and scientists working in small watercourses in the Northern Hemisphere.

  • 98.
    Lind, Lovisa
    et al.
    Umeå University, Sweden.
    Nilsson, Christer
    Umeå University, Sweden.
    Vegetation patterns in small boreal streams relate to ice and winter floods2015In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 103, no 2, p. 431-440Article in journal (Refereed)
    Abstract [en]

    In-stream and riparian vegetation are species rich, productive and dynamic. Their patterns insmall boreal streams are largely driven by seasonal flow regimes. Traditionally, flow-related processes during the growing season, particularly the spring flood, have been seen as the most important, whereas vegetation has been viewed as being dormant and ‘less affected’ during winter. Riparian and in-stream vegetation were inventoried during the summers 2011–2013 in eight reaches of northern Swedish streams. Along each reach, the ice formation was surveyed during winter by visual inspections and with permanently placed cameras. We then evaluated the potential effects of ice regimes and winter flooding on riparian and in-stream vegetation during 3 years by relating the abundance of winter floods caused by anchor ice to the cover, composition and biomass of vegetation. We found that the numbers of winter floods were higher along reaches with anchor-ice formation than in reaches without. We also found that species diversity of riparian vegetation was higher inthe reaches with anchor ice. This resulted from a lower cover of riparian dwarf shrubs and a higher cover of graminoids and forbs along reaches with anchor ice. We also found a lower cover of instream algae but a higher cover of bryophytes in anchor-ice reaches. These patterns were consistent throughout the study period although there were interannual differences in temperature, water levels and ice cover. During our study period, we encountered an average of 20 shifts per winter between freezing and thawing, while there was an average of 10 shifts per winter during 1960–1990. This indicates a warming climate in high latitudes. Higher temperatures and more shifts between freezing and thawing may initially increase ice dynamics. However, with further increases in mean temperature, ice production should eventually decrease. Synthesis. Ice and winter floods caused by anchor ice appear to be important disturbance agents that allow less competitive species to establish along small boreal streams. If ice dynamics is reduced, the composition and production of riparian and in-stream vegetation may be changed, with possible consequences for the entire stream ecosystem.

  • 99.
    Lind, Lovisa
    et al.
    Umeå University, Umeå, Sweden.
    Nilsson, Christer
    Umeå University, Umeå, Sweden.
    Polvi, Lina E.
    Umeå University, Umeå, Sweden.
    Weber, Christine
    Umeå University, Umeå, Sweden.
    The role of ice dynamics in shaping vegetation in flowing waters2014In: Biological Reviews, ISSN 1464-7931, E-ISSN 1469-185X, Vol. 89, no 4, p. 791-804Article in journal (Refereed)
    Abstract [en]

    Ice dynamics is an important factor affecting vegetation in high-altitude and high-latitude streams and rivers. During the last few decades, knowledge about ice in streams and rivers has increased significantly and a respectable body of literature is now available. Here we review the literature on how ice dynamics influence riparian and aquatic vegetation. Traditionally, plant ecologists have focused their studies on the summer period, largely ignoring the fact that processes during winter also impact vegetation dynamics. For example, the freeze-up period in early winter may result in extensive formation of underwater ice that can restructure the channel, obstruct flow, and cause flooding and thus formation of more ice. In midwinter, slow-flowing reaches develop a surface-ice cover that accumulates snow, protecting habitats under the ice from formation of underwater ice but also reducing underwater light, thus suppressing photosynthesis. Towards the end of winter, ice breaks up and moves downstream. During this transport, ice floes can jam up and cause floods and major erosion. The magnitudes of the floods and their erosive power mainly depend on the size of the watercourse, also resulting in different degrees of disturbance to the vegetation. Vegetation responds both physically and physiologically to ice dynamics. Physical action involves the erosive force of moving ice and damage caused by ground frost, whereas physiological effects - mostly cell damage - happen as a result of plants freezing into the ice. On a community level, large magnitudes of ice dynamics seem to favour species richness, but can be detrimental for individual plants. Human impacts, such as flow regulation, channelisation, agriculturalisation and water pollution have modified ice dynamics; further changes are expected as a result of current and predicted future climate change. Human impacts and climate change can both favour and disfavour riverine vegetation dynamics. Restoration of streams and rivers may mitigate some effects of anticipated climate change on ice and vegetation dynamics by, for example, slowing down flows and increasing water depth, thus reducing the potential for massive formation of underwater ice.

  • 100.
    Lind, Lovisa
    et al.
    Umeå University, Umeå, Sweden.
    Nilsson, Christer
    Umeå University, Umeå, Sweden.
    Weber, Christine
    Umeå University, Umeå, Sweden.
    Effects of ice and floods on vegetation in streams in cold regions: implications for climate change2014In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 4, no 21, p. 4173-4184Article in journal (Refereed)
    Abstract [en]

    Riparian zones support some of the most dynamic and species-rich plant communities in cold regions. A common conception among plant ecologists is that flooding during the season when plants are dormant generally has little effect on the survival and production of riparian vegetation. We show that winter floods may also be of fundamental importance for the composition of riverine vegetation. We investigated the effects of ice formation on riparian and in-stream vegetation in northern Sweden using a combination of experiments and observations in 25 reaches, spanning a gradient from ice-free to ice-rich reaches. The ice-rich reaches were characterized by high production of frazil and anchor ice. In a couple of experiments, we exposed riparian vegetation to experimentally induced winter flooding, which reduced the dominant dwarf-shrub cover and led to colonization of a species-rich forb-dominated vegetation. In another experiment, natural winter floods caused by anchor-ice formation removed plant mimics both in the in-stream and in the riparian zone, further supporting the result that anchor ice maintains dynamic plant communities. With a warmer winter climate, ice-induced winter floods may first increase in frequency because of more frequent shifts between freezing and thawing during winter, but further warming and shortening of the winter might make them less common than today. If ice-induced winter floods become reduced in number because of a warming climate, an important disturbance agent for riparian and in-stream vegetation will be removed, leading to reduced species richness in streams and rivers in cold regions. Given that such regions are expected to have more plant species in the future because of immigration from the south, the distribution of species richness among habitats can be expected to show novel patterns.

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