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  • 301. Dufour, S.
    et al.
    Huang, Y.-S.
    Rousseau, K.
    Sbaibi, M.
    LeBelle, N.
    Vidal, B.
    Marchelidon, J.
    Querat, B.
    Burzawa-Gérard, E.
    Chang, C.F.
    Schmitz, Monika
    Puberty in teleosts: New insights into the roles of peripheral signals in the stimulation of pituitary gonadotropin2000Inngår i: Reproductive Physiology of Fish,, 2000Kapittel i bok, del av antologi (Fagfellevurdert)
  • 302. Dufour, S.
    et al.
    Rousseau, K.
    Sbaihi, M.
    LeBelle, N.
    Vidal, B.
    Marchelidon, J.
    Schmitz, Monika
    Multiple neuroendocrine regulation of growth hormone in the European eel, Anquilla anquilla)2001Inngår i: J. Taiwan Fish.ResArtikkel i tidsskrift (Fagfellevurdert)
  • 303.
    Eckstein, Rolf Lutz
    Justus-Liebig-University Giessen, Germany.
    Differential effects of interspecific interactions and water availability on survival, growth and fecundity of three congeneric grassland herbs2005Inngår i: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 166, nr 2, s. 525-536Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fitness of individual plants and of populations depends on the rates of survival, growth and fecundity. This study tested whether vital rates were differentially affected by biotic interactions and water availability. The effects of manipulations of above-ground competition (through clipping) and water availability (through water addition) on the vital rates of seedlings of three species (Viola elatior Fries, Viola pumila Chaix and Viola stagnina Kit.) were analysed in dry, mesic and wet grasslands. Water addition and grassland type had the largest effects on survival (accounting for 41 and 24% of total variation, respectively) across species. Height growth rate was positively affected by grassland type (19%) and water addition (12%) and varied among species (8%), while leaf accumulation rates and reproduction were affected by grassland type and clipping. The data suggested facilitative effects of the canopy on seedling survival in the dry grassland. This study presents evidence that environmental conditions and biotic interactions may have differential effects on seedling survival, growth and reproduction. The findings highlight the complex interplay between spatial and temporal environmental variation and biotic interactions in structuring plant communities.

  • 304.
    Eckstein, Rolf Lutz
    Uppsala University.
    Nitrogen retention by Hylocomium splendens in a subarctic birch woodland2000Inngår i: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 88, nr 3, s. 506-515Artikkel i tidsskrift (Fagfellevurdert)
  • 305.
    Eckstein, Rolf Lutz
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper. Uppsala University.
    Danihelka, J
    Masaryk University, Czech republic.
    Holzel, N
    Justus-Liebig-University Giessen, Germany.
    Otte, A
    Justus-Liebig-University Giessen, Germany.
    The effects of management and environmental variation on population stage structure in three river-corridor violets2004Inngår i: Acta Oecologica, ISSN 1146-609X, E-ISSN 1873-6238, Vol. 25, nr 1-2, s. 83-91Artikkel i tidsskrift (Fagfellevurdert)
  • 306.
    Eckstein, Rolf Lutz
    et al.
    Justus-Liebig-University Giessen, Germany.
    Danihelka, Jiri
    Czech republic.
    Otte, Annette
    Variation in life-cycle between three rare and endangered floodplain violets in two regions: implications for population viability and conservation2009Inngår i: Biologia (Bratislava), ISSN 0006-3088, E-ISSN 1336-9563, Vol. 64, nr 1, s. 69-80Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We studied the demography of Viola elatior, V. pumila, and V. stagnina, three rare and endangered Central European floodplain species, to (i) analyse variation in life-cycles among congeners and between regions (Dyje-Morava floodplains, Czech Republic; Upper Rhine, Germany), (ii) to define sensitive stages in the life-cycles, and (iii) to identify possible threats for population viability and species conservation. Matrix models were based on the fate of marked individuals from a total of 27 populations over two years. We analysed population growth rate (lambda), stage distribution, net reproductive rate (R (0)), generation time, age at first reproduction, and elasticity and calculated a life table response experiment (LTRE). Most populations were declining and lambda did not differ between species or regions during the observed interval. Despite higher probabilities for survival and flowering in the Dyje populations, R (0) was higher in the Rhine populations. Also other demographic traits showed consistent differences between regions and/or species. Complex life-cycles and large variation in lambda precluded unequivocal identification of sensitive stages or vital rates for conservation. Variation between regions may be a consequence of differences in habitat quality. Our results suggest that deterministic processes such as reduced management, succession, habitat destruction, and lack of disturbance through reduced or eliminated flooding present the strongest threat for the viability and persistence of populations of the three floodplain violets as compared with stochastic processes. However, the persistent seed bank of the species may buffer populations against environmental variation and represents a reservoir for recovery after resumption of suitable land-use management.

  • 307.
    Eckstein, Rolf Lutz
    et al.
    Justus-Liebig-University Giessen, Germany.
    Donath, T W
    Justus-Liebig-University Giessen, Germany.
    Interactions between litter and water availability affect seedling emergence in four familial pairs of floodplain species2005Inngår i: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 93, nr 4, s. 807-816Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We studied seedling emergence in four familial pairs of floodplain herbs in response to the experimental manipulation of soil moisture and litter cover to analyse (i) whether the effect of litter changes from negative under humid to positive under dry conditions, and (ii) whether the response to changing water and light conditions with increasing litter cover varies among species and plant families. We carried out a controlled pot experiment using four levels of litter cover (0 g, 2 g, 4 g and 8 g litter per pot, corresponding to 0 kg m(-2), 0.2 kg m(-2), 0.4 kg m(-2) and 0.8 kg m(-2)) and two levels of water-addition, leading to constantly humid substrate or intermittently dry topsoil. Across water-additions, percentage emergence reached a peak at low levels of litter cover (0.2 kg m(-2) and 0.4 kg m(-2)). There was a significant litter x water-addition interaction in six species, with positive effects of litter under intermittently dry conditions and negative or neutral effects under constantly humid conditions. Litter lowered maximum temperature as well as amplitude, and alleviated soil humidity under low water supply, while imposing increasingly shaded conditions. Analysis of species- and family-specific responses suggested that germination under a litter cover of 0.8 kg m(-2) was significantly reduced in smaller-seeded species (i.e. those that tend to have higher light demands for germination). Our results suggest that transfer of seed-containing plant litter can aid restoration projects if applied at 0.2-0.4 kg m(-2). Below these levels, establishment of most species may be inhibited by drought, while higher amounts will increasingly suppress seedling emergence, especially of small-seeded species. In addition to facilitation effects observed between living plants, dead plant remains may also exert positive effects on establishment. The sign of the litter effect on seedling emergence depends on soil humidity, with negative effects seen above a threshold amount, which is species- and family-specific and is closely related to seed size. Whether positive litter effects in grasslands are a consequence of coevolution remains to be examined.

  • 308.
    Eckstein, Rolf Lutz
    et al.
    Justus-Liebig-University Giessen, Germany.
    Hoelzel, Norbert
    Justus-Liebig-University Giessen, Germany.
    Danihelka, Jiri
    Czech Republic.
    Biological flora of central Europe: Viola elatior, V. pumila and V. stagnina2006Inngår i: Perspectives in plant ecology, evolution and systematics, ISSN 1433-8319, E-ISSN 1618-0437, Vol. 8, nr 1, s. 45-66Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Viola elatior, V pumila and V stagnina (syn. V persicifolia) are very rare in central and western Europe and red-listed in many central European countries. To improve their conservation and to base management efforts on sound scientific knowledge, we here review the available information on their biology. A comparative approach is adopted to identify similarities and differences between the species. Special emphasis will be on taxonomy, community ecology and population biology. All three species belong to the section Viola, subsection Rostratae. Since they are morphologically rather similar and have often been misidentified, we supply the most important characters for separating the three taxa. The species share a continental distribution with a centre of occurrence in the temperate zone of eastern Europe and western Siberia, and reach their western range margin in central and western Europe. They have become rare and endangered through melioration and fragmentation of their habitats. All three species are iteroparous hemicryptophytes with a complex life cycle, a mixed mating system with chasmogamous and cleistogamous flowers, and a persistent seed bank. Viola pumila and V. stagnina occur in floodplain meadows and wet grasslands, whereas V. elatior is a typical species of alluvial woodland fringes and other ecotonal habitats bordering floodplain meadows. Viola elatior and V pumila are confined to calcareous or at least base-rich substrates, whereas V stagnina may also occur on strongly acidic soils. The violets are able to occupy a broad range of site conditions in terms of soil nutrient status and productivity. However, on fertile sites the species depend on regular disturbances that weaken competitors and enhance the germination of dormant seeds. Current information about mycorrhizal colonisation, biochemical and physiological data, and herbivores and pathogens is scarce or lacking, probably due to the rarity of the three species in central Europe. (c) 2006 Rubel Foundation, ETH Zurich. Published by Elsevier GmbH. All rights reserved.

  • 309.
    Eckstein, Rolf Lutz
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper. Uppsala University.
    Karlsson, P S
    Uppsala University.
    Above-ground growth and nutrient use by plants in a subarctic environment: Effects of habitat, life-form and species1997Inngår i: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 79, nr 2, s. 311-324Artikkel i tidsskrift (Fagfellevurdert)
  • 310.
    Eckstein, Rolf Lutz
    et al.
    Uppsala University.
    Karlsson, P S
    Uppsala University.
    Recycling of nitrogen among segments of Hylocomium splendens as compared with Polytrichum commune: Implications for clonal integration in an ectohydric bryophyte1999Inngår i: OIKOS, Vol. 86, nr 1, s. 87-96Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 311.
    Eckstein, Rolf Lutz
    et al.
    Uppsala University.
    Karlsson, P S
    Uppsala University.
    Variation in nitrogen-use efficiency among and within subarctic graminoids and herbs2001Inngår i: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 150, nr 3, s. 641-651Artikkel i tidsskrift (Fagfellevurdert)
  • 312.
    Eckstein, Rolf Lutz
    et al.
    Uppsala University.
    Karlsson, P S
    Uppsala University.
    Weih, M
    Uppsala University.
    Leaf life span and nutrient resorption as determinants of plant nutrient conservation in temperate-arctic regions1999Inngår i: New phytologist, Vol. 143, nr 1, s. 177-189Artikkel i tidsskrift (Fagfellevurdert)
  • 313.
    Eckstein, Rolf Lutz
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper. Uppsala University.
    Karlsson, P S
    Uppsala University.
    Weih, M
    Uppsala University.
    The significance of resorption of leaf resources for shoot growth in evergreen and deciduous woody plants from a subarctic environment1998Inngår i: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 81, nr 3, s. 567-575Artikkel i tidsskrift (Fagfellevurdert)
  • 314.
    Eckstein, Rolf Lutz
    et al.
    Uppsala University.
    Karlsson, P. Staffan
    Abisko Scientific Research Station.
    The effect of reproduction on nitrogen use-efficiency of three species of the carnivorous genus Pinguicula2001Inngår i: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 89, nr 5, s. 798-806Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Life history theory predicts that reproduction incurs costs in terms of future growth and survival. In infertile environments reproductive events may accelerate nutrient turnover such that losses of limiting nutrients cannot be replenished by uptake from the soil. 

    We compared the effect of reproduction on nitrogen (N) turnover and N use-efficiency, i.e. the annual dry matter produced per unit N lost, of three carnivorous species of the genus Pinguicula on an infertile subarctic heath. We hypothesized that reproduction should increase N turnover, unless a larger N pool or improved N resorption can compensate for the losses associated with reproduction.

    These carnivorous herbs showed a nitrogen use strategy similar to that of non-carnivorous plants (herbs and grasses) with a relatively low mean residence time (MRT) of N and a large dry matter productivity per unit N in the plant (annual N productivity). N pool size and the efficiency of N resorption from senescent leaves were similar in reproductive and non-reproductive individuals. Reproductive individuals had significantly larger annual N losses and thus a lower average MRT (0.8 vs. 1.8 years), with values < 1 indicating that the annual N losses are greater than the annual average N pool. Unless plants can enhance their nutrient acquisition, flowering may therefore impact on future growth and survival.

    This study presents evidence for a direct link between reproduction, reflected in a higher relative allocation to inflorescences, turnover and N use-efficiency; the latter being reduced because of increased N turnover. The ranking of species in terms of reproductive allocation was the reverse of their ranking in terms of their N use-efficiency.

  • 315.
    Eckstein, Rolf Lutz
    et al.
    Justus-Liebig-University Giessen, Germany.
    O'Neill, R. A.
    Justus-Liebig-University Giessen, Germany.
    Danihelka, J.
    Justus-Liebig-University Giessen, Germany.
    Otte, A.
    Justus-Liebig-University Giessen, Germany.
    Koehler, W.
    Justus-Liebig-University Giessen, Germany.
    Genetic structure among and within peripheral and central populations of three endangered floodplain violets2006Inngår i: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 15, nr 9, s. 2367-2379Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Understanding the partitioning of genetic variance in peripheral and central populations may shed more light on the effects of genetic drift and gene flow on population genetic structure and, thereby, improve attempts to conserve genetic diversity. We analysed genetic structure of peripheral and central populations of three insect-pollinated violets (Viola elatior, Viola pumila, Viola stagnina) to evaluate to what extent these patterns can be explained by gene flow and genetic drift. Amplified fragment length polymorphism was used to analyse 930 individuals of 50 populations. Consistent with theoretical predictions, peripheral populations were smaller and more isolated, differentiation was stronger, and genetic diversity and gene flow lower in peripheral populations of V. pumila and V. stagnina. In V. elatior, probably historic fragmentation effects linked to its specific habitat type were superimposed on the plant geographic (peripheral-central) patterns, resulting in lower relative importance of gene flow in central populations. Genetic variation between regions (3-6%), among (30-37%) and within populations (60-64%) was significant. Peripheral populations lacked markers that were rare and localized in central populations. Loss of widespread markers in peripheral V. stagnina populations indicated genetic erosion. Autocorrelation within populations was statistically significant up to a distance of 10-20 m. Higher average genetic similarity in peripheral populations than in central ones indicated higher local gene flow, probably owing to management practices. Peripheral populations contributed significantly to genetic variation and contained unique markers, which made them valuable for the conservation of genetic diversity.

  • 316.
    Eckstein, Rolf Lutz
    et al.
    Justus-Liebig-University Giessen.
    Otte, A
    Justus-Liebig-University Giessen.
    Effects of cleistogamy and pollen source on seed production and offspring performance in three endangered violets2005Inngår i: Basic and Applied Ecology, ISSN 1439-1791, E-ISSN 1618-0089, Vol. 6, nr 4, s. 339-350Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In rare plants that often occur in small or isolated populations the probability of selfing between close relatives is increased as a consequence of demographic stochasticity. The mode of pollination (selfing, outcrossing) may have considerable effects on seed traits and offspring performance and hence potential viability. Since current efforts aiming at the restoration of floodplain grasslands through the transfer of plant material from species-rich source stands may lead to the establishment of initially small populations consisting of founders from different populations, the present paper experimentally investigated the effects of pollen source and floral types (i.e. chasmogamous (CH) and cleistogamous (CL) flowers) on seed traits and offspring performance in three highly endangered violet species (Viola elatior, V. pumila, V. stagnina) of these grasslands. We estimated inbreeding depression and tested the performance of selfed and outcrossed offspring in two microbial environments, i.e. in soil inoculated with (i) non-sterile substrate from the same species ('home'-conditions) and (ii) sterilised substrate. Plants produced more CL capsules than CH flowers. Pollinator exclusion had only small effects on CH seed production. CL seeds had a significantly lower mass per seed than CH seeds. This may be related to constraints in allocation or environmental conditions. Seedling growth was reduced in plants grown under 'home'-conditions as compared to control soils. Under 'home'-conditions, relative fitness of selfed seedlings of V. stagnina was significantly higher than that of crossed progeny. Our results suggest that high genetic differentiation among populations as a consequence of isolation may result in outbreeding depression, e.g., through biochemical or physiological incompatibilities between genes or the breaking of coadapted gene complexes. In V. stagnina, offspring fitness differed considerably between environments, but in general we found no indications for inbreeding depression in these rare species. (c) 2005 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.

  • 317.
    Eckstein, Rolf Lutz
    et al.
    Justus-Liebig-University Giessen.
    Otte, Annette
    Justus-Liebig-University Giessen.
    Evidence for consistent trait-habitat relations in two closely related violets of contiguous habitat types from a fertilisation experiment2004Inngår i: Flora: Morphologie, Geobotanik, Oekophysiologie, ISSN 0367-2530, E-ISSN 1618-0585, Vol. 199, nr 3, s. 234-246Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Most studies on the adaptive significance of plant traits compared species that differed in inherent growth rate or species of habitats at the extremes of environmental gradients. In the present paper, we compared the response of Viola elatior and V. pumila, two closely related and morphologically similar violets to the experimental variation of nitrogen availability. The species occur in adjacent habitat types, viz. alluvial forest fringes (V. elatior) and floodplain meadows (V. pumila), that differ in resource availability and disturbance across a relatively small gradient. We tested the hypotheses that, according to their typical habitat, V. elatior should show more traits of a stress tolerant competitive plant, while V. pumila should exhibit more ruderal traits. We carried out a two-year common garden experiment with two levels of fertiliser addition (N5, 5 g N m(-2) yr(-1); N20, 20 g N m(-2) yr(-1)), and analysed a number of traits related to relative growth rate (RGR), allocation, and nutrient use. We further did an experiment with seeds from the experimental plants to study variation in germination rate. We found considerable ontogenetic drift in the species during two years of growth. In the first year, both species showed similar mass and growth rate but these were achieved through different trait combinations. In the second year, V. elatior had a higher RGR, produced more biomass per unit nutrient and developed more leaf area per unit plant mass than V. pumila, while the latter produced thinner leaves. V. pumila had a higher capacity for nutrient acquisition, but a large proportion of the captured nutrients were used for reproduction. Germination rate was higher in V. pumila than in V. elatior, independent of the nutrient status of the mother plant, while seeds of V. elatior from N20 plants had a significantly higher germination rate (67%) than seeds from N5 plants (35%). Our data suggested that many of the analysed trait differences seem to be consistent with the requirements of the different habitat types.

  • 318.
    Eckstein, Rolf Lutz
    et al.
    Justus-Liebig-University Giessen, Germany.
    Pereira, Eva
    Justus-Liebig-University, Giessen, Germany.
    Milbau, Ann
    Justus-Liebig-University, Giessen, Germany.
    Graae, Bente Jessen
    Justus-Liebig-University, Giessen, Germany.
    Predicted changes in vegetation structure affect the susceptibility to invasion of bryophyte-dominated subarctic heath2011Inngår i: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 108, nr 1, s. 177-183Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background and Aims A meta-analysis of global change experiments in arctic tundra sites suggests that plant productivity and the cover of shrubs, grasses and dead plant material (i.e. litter) will increase and the cover of bryophytes will decrease in response to higher air temperatures. However, little is known about which effects these changes in vegetation structure will have on seedling recruitment of species and invasibility of arctic ecosystems. Methods A field experiment was done in a bryophyte-dominated, species-rich subarctic heath by manipulating the cover of bryophytes and litter in a factorial design. Three phases of seedling recruitment (seedling emergence, summer seedling survival, first-year recruitment) of the grass Anthoxanthum alpinum and the shrub Betula nana were analysed after they were sown into the experimental plots. Key Results Bryophyte and litter removal significantly increased seedling emergence of both species but the effects of manipulations of vegetation structure varied strongly for the later phases of recruitment. Summer survival and first-year recruitment were significantly higher in Anthoxanthum. Although bryophyte removal generally increased summer survival and recruitment, seedlings of Betula showed high mortality in early August on plots where bryophytes had been removed. Conclusions Large species-specific variation and significant effects of experimental manipulations on seedling recruitment suggest that changes in vegetation structure as a consequence of global warming will affect the abundance of grasses and shrubs, the species composition and the susceptibility to invasion of subarctic heath vegetation.

  • 319.
    Eckstein, Rolf Lutz
    et al.
    Justus-Liebig-University Giessen, Germany.
    Ruch, Diana
    Otte, Annette
    Justus-Liebig-University, Giessen, Germany.
    Donath, Tobias W.
    Justus-Liebig University, Giessen, Germany.
    Invasibility of a Nutrient-Poor Pasture through Resident and Non-Resident Herbs Is Controlled by Litter, Gap Size and Propagule Pressure2012Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, nr 7, artikkel-id e41887Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Since inference concerning the relative effects of propagule pressure, biotic interactions, site conditions and species traits on the invasibility of plant communities is limited, we carried out a field experiment to study the role of these factors for absolute and relative seedling emergence in three resident and three non-resident confamilial herb species on a nutrient-poor temperate pasture. We set up a factorial field experiment with two levels each of the factors litter cover (0 and 400 g m(-2)), gap size (0.01 and 0.1 m(2)) and propagule pressure (5 and 50 seeds) and documented soil temperature, soil water content and relative light availability. Recruitment was recorded in spring and autumn 2010 and in spring 2011 to cover initial seedling emergence, establishment after summer drought and final establishment after the first winter. Litter alleviated temperature and moisture conditions and had positive effects on proportional and absolute seedling emergence during all phases of recruitment. Large gaps presented competition-free space with high light availability but showed higher temperature amplitudes and lower soil moisture. Proportional and absolute seedling recruitment was significantly higher in large than in small gaps. In contrast, propagule pressure facilitated absolute seedling emergence but had no effects on proportional emergence or the chance for successful colonisation. Despite significantly higher initial seedling emergence of resident than non-resident species, seed mass and other species-specific traits may be better predictors for idiosyncratic variation in seedling establishment than status. Our data support the fluctuating resource hypothesis and demonstrate that the reserve effect of seeds may facilitate seedling emergence. The direct comparison of propagule pressure with other environmental factors showed that propagule pressure affects absolute seedling abundance, which may be crucial for species that depend on other individuals for sexual reproduction. However, propagule batch size did not significantly affect the chance for successful colonisation of disturbed plots.

  • 320.
    Edwartz, Johannes
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper (from 2013).
    Weight losses of Green tea and Rooibos tea in an aquatic environment: The importance of leaching when estimating decomposition rates2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

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

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  • 321.
    Ehrlander, Christine
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013).
    Blomsterlupinens olika blomfärger i relation till bebyggelse och breddgrad2020Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Blomsterlupin, Lupinus polyphyllus, är en invasiv art som introducerades i Europa som trädgårdsväxt på 1800-talet. Arten har sedan spridits och finns idag vild i stora delar av Europa. Mänskliga aktiviteter antas ha en betydande påverkan på växtens spridning. Trädgårdslupin visar en stor variation i blomfärger; där blått är den genetiskt dominerande och vanligaste färgen. I denna studie ville jag testa om avståndet till bebyggelse påverkar mångfalden i olika blomfärger och om den blå färgen blir mer dominerande, desto längre bort från bebyggelsen växtplatsen är lokaliserad. Jag undersökte också om det fanns något samband mellan mångfalden av olika blomfärger och breddgraden för växtplatsen. Det fanns inga signifikanta samband mellan de olika variablerna för vilka jag utförde regressionsanalys, men det fanns vissa trender med p-värde <0,06. Det fanns en tendens till samband mellan den ökade variationen i effektivt antal huvudfärger med latitud, vilket skulle stödja min initiala hypotes. Det fanns också en tendens att det effektiva antalet blomfärger ökade när man minskade avståndet till närmaste hus, vilket ger ett visst stöd till uppfattningen att mänskliga aktiviteter påverkar förekomsten av olika blomfärger genom multipla introduktioner. 

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    Blomsterlupinens olika blomfärger i relation till bebyggelse och breddgrad
  • 322.
    Einarsson, Maria
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper.
    Barns utevistelse på förskolan: Utemiljöns inverkan på barns lekar och naturintresse2007Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Through interviews with children of ages 4-5 years old and by observing children children at play at three preschools with different types of outdoor surroundings, I have investigated if the preschools outdoor surroundings have any influences on the children´ choice of play. The hypothesis was that natural surroundings can entice children´s interest in nature being in it and play. I have also investigated if the children know why it is important to be outdoors and if they know it has a positive influence on their health.

    The result of my investigation is that the children play about the same games at the three different preschool gardens, but at the preschool with more natural surroundings, the children have more contact with plants and animals, and could learn of the different phenomena of nature by the preschool teacher answering their questions. Most of the children in the interviews know it´s useful to be outdoors and be on the move and get fresh air, but many of them thought it was most important to play. By being outdoors the children get exercise, fresh air, play and at the same time they establish an understanding of the nature and a healthier life.

    Fulltekst (pdf)
    FULLTEXT01
  • 323.
    Eklo, Niklas
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013).
    Effekten av temperatur under äggstadiet på Atlantlaxyngelns (Salmo salar) gälslagsfrekvens2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Enligt klimatexperter (IPCC) kommer den globala medeltemperaturen att höjas, speciellt på vintern när laxägg utvecklas i gruset. Frågan är hur denna temperaturhöjning kommer påverka laxen, med tanke på vad tidigare studier om inkuberingstemperatur under äggstadiet visats ge för effekter på morfologi, tillväxt och metabolism. Denna studie syftade till att undersöka eventuella skillnader i gälslagsfrekvens hos laxyngel beroende på deras inkuberingstemperatur under äggstadiet. Nykläckt lax inkuberad i normaltempererat, delvis uppvärmt och helt uppvärmt vatten (uppvärmd 3-6oC) filmades i svagt ljus och gälslagsfrekvensen räknades ut. Resultatet visade att fiskarna utsatta för en uppvärmd inkuberingstemperatur hade lägre gälsslagsfrekvens än de andra två behandlingarna. För att kontrollera om effekten kunde kopplas till olikheter i fiskens livsstadium istället för inkuberingstemperatur, testades de delvis uppvärmda laxarna två gånger, en gång när de hade gulesäck och en gång när de inte hade gulesäck. Jag fann att fiskar utan gulesäck hade lägre gälsslagsfrekvens än fiskar med gulesäck. Detta betyder att individernas utvecklingsstadium kan ha haft en påverkan på gälslagsfrekvensen och då kan jag inte avgöra om den lägre gälslagsfrekvensen är ett resultat av inkuberingstemperatur eller utvecksstadiet. Framtida studier bör undersöka noggrannare hur varierande inkuberingstemperatur påverkar resultatet, samt sträva efter att genomföra testerna på individer i samma utvecklingsstadium. 

  • 324. Eklöv, A. G.
    et al.
    Greenberg, Larry
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper, Avdelningen för biologi.
    Effect of artificial instream cover on density of 0+ brown trout1998Inngår i: Fisheries Management & Ecology 5: 45-53Artikkel i tidsskrift (Fagfellevurdert)
  • 325. Eklöv, A.
    et al.
    Greenberg, Larry
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper, Avdelningen för biologi.
    Brönmark, C.
    Larsson, P.
    Berglund, O.
    Influence of water quality, habitat and speciess richness on brown trout populations1999Inngår i: J. Fish Biology 54: 33-43Artikkel i tidsskrift (Fagfellevurdert)
  • 326. Eklöv, A.
    et al.
    Greenberg, Larry
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper, Avdelningen för biologi.
    Brönmark, C.
    Larsson, P.
    Berglund, O.
    Response of stream fish to improved water quality: a comparison between the 1960s and 1990s1998Inngår i: Freshwater Biology 40: 771-782Artikkel i tidsskrift (Fagfellevurdert)
  • 327. Eklöv, A.
    et al.
    Greenberg, Larry
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper, Avdelningen för biologi.
    Kristiansen, H.
    The effect of depth on the interaction between perch (Perca fluviatilis) and minnow (Phoxinus phoxinus)1994Inngår i: Ecology of Freshwater Fish 3: 1-8Artikkel i tidsskrift (Fagfellevurdert)
  • 328.
    Ekman, Malin
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013).
    The effect of climate on vegetation cover in Swedish mountain regions2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Climate change, with a higher temperature, is making the snow covered period shorter in the Swedish mountain region. This represents a threat towards plant species at high altitudes which, due to their sensitivity to temperature changes, will likely lead to a change in plant species composition. The purpose of this study was to determine if there has been any change in vegetation cover in the Swedish mountain region and if temperature has changed, based on data from a long-term monitoring program called National Inventory of Landscapes in Sweden (NILS), and data collected from the Swedish Meteorological and Hydrological Institute (SMHI). The NILS program has conducted three different inventories from 2003 – 2018 in which Sweden is divided into 10 stratums. Further, NILS divided Sweden into 631 survey quadrates (5x5 km), which of 145 were distributed across the Swedish mountain region. Linear regression analysis was used to determine if there had been any change in the average vegetation cover, or in the cover of lichens, mosses and herbs, and to assess if there had been any change in temperature during the sample years 2003 – 2018. The results showed that the vegetation cover in both the sample blocks of 20 m radius and smaller sample areas 0.252 m had no significant change. Neither did the cover of herbs or the average temperature. The period of 2003 – 2018 might have been too short of a period to see any kind of difference in the temperature and the herbs might have a difficult time surviving due to a long drought period and hence they have not been able to increase their average cover. Results of lichens and mosses showed a significant increase in cover which could be because they can withstand drought better than herbs and therefore have a better chance of surviving the rise in temperature. In conclusion I observed no change in the cover of vegetation but there is an increasing cover of lichens and mosses in the Swedish mountain regions.

    Fulltekst (pdf)
    fulltext
  • 329.
    Ekstrom, Sara M.
    et al.
    Lund Univ, Dept Biol, Aquat Ecol, Lund, Sweden..
    Regnell, Olof
    Lund Univ, Dept Biol, Aquat Ecol, Lund, Sweden..
    Reader, Heather E.
    Lund Univ, Dept Biol, Aquat Ecol, Lund, Sweden..
    Nilsson, P. Anders
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper. Lund Univ, Dept Biol, Aquat Ecol, Lund, Sweden.
    Lofgren, Stefan
    Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden..
    Kritzberg, Emma S.
    Lund Univ, Dept Biol, Aquat Ecol, Lund, Sweden..
    Increasing concentrations of iron in surface waters as a consequence of reducing conditions in the catchment area2016Inngår i: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 121, nr 2, s. 479-493Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recent studies report trends of strongly increasing iron (Fe) concentrations in freshwaters. Since Fe is a key element with a decisive role in the biogeochemical cycling of major elements, it is important to understand the mechanisms behind these trends. We hypothesized that variations in Fe concentration are driven mainly by redox dynamics in hydraulically connected soils. Notably, Fe(III), which is the favored oxidation state except in environments where microbial activity provide strong reducing intensity, has several orders of magnitude lower water solubility than Fe(II). To test our hypothesis, seasonal variation in water chemistry, discharge, and air temperature was studied in three Swedish rivers. Methylmercury and sulfate were used as indicators of seasonal redox changes. Seasonal variability in water chemistry, discharge, and air temperature in the Eman and Lyckeby Rivers implied that the variation in Fe was primarily driven by the prevalence of reducing conditions in the catchment. In general, high Fe concentrations were observed when methylmercury was high and sulfate was low, indicative of reducing conditions. The Fe concentrations showed no or weak relationships with variations in dissolved organic matter concentration and aromaticity. The seasonal variation in Fe concentration of the Ume river was primarily dependent on timing of the snowmelt in high- versus low-altitude areas of the catchment. There were long-term trends of increasing temperature in all catchments and also trends of increasing discharge in the southern rivers, which should increase the probability for anaerobic conditions in space and time and thereby increase Fe transport to the aquatic systems.

  • 330.
    Ekström, S
    et al.
    Lunds universitet.
    Kritzberg, E
    Lunds universitet.
    Berggren Kleja, D
    Uppsala universitet.
    Larsson, N
    Lunds universitet.
    Nilsson, P. Anders
    Lunds universitet.
    Granéli, W
    Lunds universitet.
    Bergkvist, B
    Lunds universitet.
    The effect of acid deposition on quantity and quality of dissolved organic matter in soil-water2011Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 45, nr 11, s. 4733-4739Artikkel i tidsskrift (Fagfellevurdert)
  • 331.
    Ekström, Sara M.
    et al.
    Lund University.
    Sandahl, Margareta
    Lund University.
    Nilsson, Per Anders
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper. Lund University.
    Kleja, Dan B.
    Swedish University of Agricultural Sciences.
    Kritzberg, Emma S.
    Lund University.
    Reactivity of dissolved organic matter in response to acid deposition2016Inngår i: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 78, nr 3, s. 463-475Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 332. Elso, J. I.
    et al.
    Greenberg, Larry
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper, Avdelningen för biologi.
    Habitat use, movements and survival of individual 0+ brown trout (Salmo trutta) during winter2001Inngår i: Archiv für Hydrobiologie 152: 279-295, Vol. 152Artikkel i tidsskrift (Fagfellevurdert)
  • 333. Emanuelsson, Marie
    et al.
    Bergquist, Ulla
    Segerström, Ulf
    Svensson, Eva
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper.
    von Stedingk, Henrik
    Shieling or something else?: Iron age and medieval forest settlement and land use at Gammelvallen in Ängersjö, Central Sweden2000Inngår i: Lund archeological review, Vol. 6Artikkel i tidsskrift (Fagfellevurdert)
  • 334. Emanuelsson, Marie
    et al.
    Johansson, Annie
    Nilsson, Stefan
    Pettersson, Susanne
    Svensson, Eva
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper.
    Settlement, shieling and landscape: The local history of a forest hamlet2003Bok (Fagfellevurdert)
  • 335.
    Enefalk, Åsa
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper.
    Fine stream wood: effects on drift and brown trout (Salmo trutta) growth and behaviour2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Stream ecosystems and their riparian zones have previously been regarded as two different ecosystems, linked through numerous reciprocal subsidies. Today, ecologists agree that the stream and the riparian zone should be regarded as one system, the stream-riparian ecosystem, which is characterised largely by the subsidies between land and water. The terrestrial subsidies to the stream affect stream-living biota in several ways, some of which are well-known while others less so. The input of wood to the stream from the riparian zone is believed to play an important role in the population dynamics of stream-living fish. In this doctoral thesis, I explore effects of fine stream wood (FW, <10 cm diameter) on wild stream-living young-of-the-year brown trout (Salmo trutta) by reporting and discussing results from laboratory, semi-natural and field experiments. My results show that the local density of drifting prey is higher in the presence of FW than in its absence, and also that young-of-the-year brown trout decrease their diurnal foraging time and prey capture success when FW is added to their habitat. I show that trout decrease their swimming activity in the presence of FW, aggregate in FW bundles, and have lower growth rates than trout without FW access. Also, the degree of sheltering in FW bundles was higher during day than at night in a study performed at low water temperatures; moreover, the presence of an ectothermic nocturnal predator (burbot, Lota lota) did not affect the degree of sheltering in FW bundles by trout. Taken together, my results indicate that young-of-the-year brown trout with access to FW bundles spend considerable amounts of time sheltering in the FW, and by doing so they miss the opportunity for higher growth and foraging rates outside of the shelter. The most probable explanation for this behaviour is that growth is traded off against survival, i.e., the predation risk is higher outside of the shelter.

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  • 336.
    Enefalk, Åsa
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper.
    Bergman, Eva
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper.
    Effect of fine wood on juvenile brown trout behaviour in experimental stream channels2016Inngår i: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, Vol. 25, nr 4, s. 664-673Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 337.
    Enefalk, Åsa
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper.
    Bergman, Eva
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper.
    Effects of fine wood on macroinvertebrate drift in four boreal forest streams2016Inngår i: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 765, nr 1, s. 317-327Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Most studies of stream wood have focused on pieces a parts per thousand yen0.1 m diameter. However, this approach may overlook an important feature of small streams, where wood < 0.1 m can constitute the majority of wood pieces. We examined the effect of fine wood (FW) on local drift of stream macroinvertebrates. The study was carried out at seven sites in four boreal forest streams, from early June to mid-August 2011. This was done by anchoring bundles of FW at each site and measuring drift upstream and downstream of each bundle. We hypothesized that FW would increase drift density, biomass and diversity of aquatic invertebrates. Ten weeks after FW addition, aquatic drift density was higher downstream than upstream of FW bundles, while drift biomass and drift diversity did not differ significantly downstream and upstream of FW.

  • 338.
    Enefalk, Åsa
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper (from 2013).
    Huusko, Ari
    National Resources Institute, Finland.
    Louhi, Pauliina
    University of Oulu, Finland.
    Bergman, Eva
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper (from 2013).
    Fine stream wood decreases growth of juvenile brown trout (Salmo trutta)2019Inngår i: Environmental Biology of Fishes, ISSN 0378-1909, E-ISSN 1573-5133, Vol. 102, nr 5, s. 759-770Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, the growth rate, gut fullness, diet composition and spatial distribution of brown trout was compared between artificial channels with and without fine wood (FW). Access to FW resulted in significantly lower brown trout growth rates over the study period from late summer to early winter as water temperatures declined from 17 °C to 1 °C. Access to FW resulted in minor differences in occurrence of the most common taxa found in brown trout diets, except for chironomid larvae which were found in c. 60% of the brown trout guts from control treatments but in only 30% of the guts from FW treatments in early winter. Diet consisted primarily of case-bearing and free-living Trichoptera larvae, Asellus, chironomid and Ephemeroptera larvae. Brown trout gut fullness was not significantly affected by access to FW bundles. Brown trout aggregated among FW but were more evenly distributed in channels lacking it. Our results suggest that juvenile brown trout use FW as a shelter at a wide range of water temperatures, and that this behaviour may result in reduced growth rates during their first fall and the onset of their first winter. We also show that prey availability and the composition of brown trout diet changes from late summer to early winter and that FW has a small but significant effect on brown trout diet composition.

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  • 339.
    Enefalk, Åsa
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper (from 2013).
    Watz, Johan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper (from 2013).
    Greenberg, Larry
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper (from 2013).
    Bergman, Eva
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper (from 2013).
    Winter sheltering by juvenile brown trout (Salmo trutta): Effects of stream wood and an instream ecothermic predator2017Inngår i: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 62, nr 1, s. 111-118Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 340.
    Enfjäll, Emma
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013).
    Värderingar om laxfisk och laxfisket som ekosystemtjänst: En enkätundersökning2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Människans beroende av naturens resurser speglas genom de ekosystemtjänster som jordens ekosystem tillhandahåller. Ekosystemtjänster delas in i stödjande, reglerande, försörjande och kulturella tjänster. I den här undersökningen skickades en webbaserad enkät ut till de som på ett eller annat sätt kom i kontakt med laxfisk och laxfisket på sin fritid och/eller i sitt yrke. Syftet med undersökningen var att ta reda på till vilken grad utbildning och typ av fiskare man anser sig vara, påverkar förståelsen för och värderingen av laxfisk som ekosystemtjänst. Vidare ville man ta reda på om förekomst av vild eller odlad laxfisk, ursprunglig stam, vandringshinder och restaureringar påverkade värdering av laxfisken som ekosystemtjänst. Respondenterna fick värdera sex ekosystemtjänster förknippade med laxfisk och laxfiske på en skala 1-5. Resultatet visar att utbildning påverkar dels förståelsen för ekosystemtjänstbegreppet och dels värderingen av biodiversitet som ekosystemtjänst. Av de fyra kategorierna av ekosystemtjänster värderades kulturella tjänster högst. Förekomst av vild lax, ursprungliga stammar och restaureringar bidrog till en högre värdering av de kulturella tjänsterna.

  • 341.
    Engqvist, Thérèse
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper.
    Avledning av öringsmolt (Salmo trutta) från turbinintag2009Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Vattenkraftstationer, med dammar och turbiner, utgör hinder för nedströmsvandrande smolt. Syftet med denna studie var att undersöka turbindödligheten för öringsmolt (Salmo trutta) vid två kraftstationer, de befintliga ytlänsarnas avledningseffekt och om effekten kunde förstärkas genom mörkläggning i form av övertäckning av kraftkanalen med en presenning vid turbinintaget. Utöver detta var avsikten även att undersöka om det fanns något samband mellan smoltgrad och smoltens förmåga att förflytta sig mot havet. I Emån i Småland fångades 46 öringsmolt som radiomärktes och sattes ut vid två kraftstationer och pejlades dagligen i sex veckor. Det var en större dödlighet vid den övre stationen än vid den nedre. Ytlänsen vid den nedre stationen hade en klart avledande effekt, men inte ytlänsen vid den övre stationen. Samtliga smolt som valde passage via isutskovet, gjorde det när kraftkanalen vid turbinintaget var övertäckt med presenning (d.v.s. ljusintensiteten minskades kraftigt). Det gick inte att påvisa någon skillnad mellan låg och hög smoltgrad eller tidig och sen utsättning för fördröjning vid den ena kraftstationen, inte heller för förflyttning efter de två kraftstationerna.

    Fulltekst (pdf)
    FULLTEXT01
  • 342. Eriksen, A.
    et al.
    Wabakken, P.
    Zimmerman, Barbara
    Andreassen, H. P.
    Arnemo, J. M.
    Gundersen, H.
    Milner, E J. M.
    Liberg, O.
    Linnell, J. D. C.
    Pedersen, H. C.
    Sand, H.
    Solberg, E. J.
    Storaas, T.
    Encounter frequencies between GPS-collared wolves (Canis lupus) and moose (Alces alces) in a Scandinavian wolf territory2008Inngår i: Ecological ResearchArtikkel i tidsskrift (Fagfellevurdert)
  • 343.
    Eriksson, Emelie
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper, Avdelningen för biologi.
    Sömnens betydelse för hälsa och inlärning: En studie om uppfattningar hos elever i årskurs 62013Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Sleep has a substantial effect on health status where good sleeping habits proves positive on learning. The aim of the present study was to map the views and perceptions of sleep and its effects on health and school performance on 12-year olds. The goal is to visualize these views to give teachers the possibility to better plan the education in concordance with the students’ abilities. The study is based on qualitative semi-structured interviews where 12 students aged 12 have partaken. The results show that while the majority of children interviewed know how long they need to sleep for optimal performance but many think that they are not sleeping sufficiently due to temptation from digital media. The children have the perception that we need to sleep to gather energy and for the brain to rest. In agreement with this, they are aware that too little sleep can impact school performance in a negative way. However, they are unaware that bad sleeping habits can have a negative impact also on the physical health.

    Fulltekst (pdf)
    Sömnens betydelse för hälsa och inlärning.
  • 344.
    Eriksson, Ida
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper.
    Barns tankar om den egna kroppen: En undersökning om barns uppfattningar med uppföljning efter 18 månader2009Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med rapporten var att undersöka hur barn i åldern fyra-fem år tänker om sin egen kropp, vilka uppfattningar om kroppen som finns. Sju barn har deltagit genom kvalitativa intervjuer och en uppföljning ca 18 månader senare visar hur uppfattningarna förändrats eller utvecklats. Barnen blev även erbjudna att måla en teckning som visade insidan på en människokropp.

       Barnens svar var bundna till situationer och uppfattningarna om kroppen hade utvecklats sedan de första intervjuerna, även om en del svar var ganska lika. Barnens spontana svar om den egna kroppen var många; det finns ett hjärta, hjärna, skelett, blod för att nämna några svar. Några av barnen kände till hjärtat och hjärnans funktion.

       Barnen fick också besvara frågor om vad som händer med maten vi äter, vad som händer med människokroppen när man blir gammal och om sjukdom. Fyra barn berättade att maten först hamnar i magen och därefter i rumpan/toaletten, de andra barnen menade att maten stoppar i magen. När man blir gammal menade några barn att man dör eller att kroppen blir trött och orkar mindre. Barnen berättade även om olika sjukdomar de haft eller känner till, om medicin och att man kan bli sjuk genom smitta.

    Fulltekst (pdf)
    FULLTEXT01
  • 345.
    Eriksson, Ida
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013).
    Undervisning i sex och samlevnad på högstadiet: Har lärarens arbetserfarenhet någon betydelse?2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Idag ska ungdomarna i högstadieskolan både hitta sig själva som individer och en sexualitet de känner sig trygga med, i ett samhälle där många och ofta motsägelsefulla bilder om sexualitet flödar. I dagens skola finns begrepp som kan kopplas till sex och samlevnad inskrivna i flera ämnes- och kursplaner och dessa ska finnas med under hela grundskolan. Flera studier visar att många elever upplever att sex och samlevnadsundervisningen är dålig, trots att skolan har en viktig roll som informatör. Syftet med min studie var att se om det finns några skillnader mellan lärare som arbetat olika länge som lärare med avseende på hur de upplever sex- och samlevnadsundervisningen. Frågeställningarna i studien var hur sex- och samlevnadsundervisningen planeras och genomförs, när den sker och hur styrdokumenten tolkas som är kopplade till skolans sex- och samlevnadsundervisning? Fyra kvinnliga pedagoger som är utbildade och undervisar i biologi har intervjuats. Två av dem har arbetat i mindre än tre år och två har arbetat i mer än fem år. Resultatet visar att det inte finns någon erfarenhetsbaserad skillnad på hur pedagogerna planerar undervisningen, innehållet i undervisningen eller när det kommer till tolkningar av läroplanen. När det gäller läroplanen finns istället en individbaserad skillnad där den pedagog som arbetat längst, har störst insikt i vad som står i läroplanen. Den största skillnaden mellan grupperna i studien visas när det kommer till pedagogernas egen utbildning i sex och samlevnad samt pedagogernas upplevelser av att utvecklaa. De pedagoger som arbetat kortast tid upplever att de fått väldigt lite utbildning inom området tillskillnad från de mer erfarna pedagogerna som upplever att de fått mer utbildning inom området. Samtidigt vill de mer erfarna pedagogerna utveckla sex- och samlevnadsundervisningen genom bättre materiel medan de mindre erfarna vill utveckla den genom att området bör synas mer under lärarutbildningen.

    Fulltekst (pdf)
    Sex och samlevnad
  • 346.
    Eriksson, Sandra
    Karlstads universitet, Fakulteten för humaniora och samhällsvetenskap (from 2013), Institutionen för pedagogiska studier.
    Är en sten levande?: En studie om barns föreställningar om vad som är levande2016Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    The purpose of this study was to investigate the children’s thoughts and opinions about what is living and non - living. Whether they believe that animals and plants are living, and about the beliefs that children have about things that are non-living and living. There were four six year old children who were included in the study and the methodology used in this study was a semi -structured interview. I used twelve pictures of different living things and non - living things. I showed the pictures to the children and posed various questions that resulted in different responses and reactions from the children. The results from this method was the children's general views on what was living and non - living. With the grounds that if something can move, it's alive.

    Fulltekst (pdf)
    fulltext
  • 347.
    Erlandsson, Ann
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Effects of 177Lu-DOTA-Tyr3-octreotate on small cell lung cancer studied by immunohistochemistry, oral presentation2007Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 348.
    Erlandsson, Ann
    Karlstads universitet, Institutionen för kemi.
    Idiotypic and antiidiotypic antibodies, Oral presentation2005Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 349.
    Erlandsson, Ann
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Forssell-Aronsson, Eva
    Seidal, Tomas
    Bernhardt, Peter
    Binding of TS1, an anti-keratin 8 antibody, in small cell lung cancer after 177Lu-DOTA-Tyr3-octreotate treatment: a histological study in xenografted mice2011Inngår i: EJNMMI Research, ISSN 2191-219X, E-ISSN 2191-219X, Vol. 1, nr 19Artikkel i tidsskrift (Fagfellevurdert)
  • 350.
    Erlandsson, Ann
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Holm, P
    Jafari, R
    Stigbrand, T
    Sundström, _
    ScFv construct and functional mapping of the monoclonal antiidiotypic antibody aTS12003Konferansepaper (Annet (populærvitenskap, debatt, mm))
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