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  • 1. Adler, P H
    et al.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Predation on black flies (Diptera: Simuliidae) by the carnivorous plant Pinguicula vulgaris (Lentibulariaceae) in northern Sweden2004Ingår i: Entomologica Fennica, ISSN 0785-8760, Vol. 15, s. 124-128Artikel i tidskrift (Refereegranskat)
  • 2. Bernhard, E
    et al.
    Bunn, S E
    Hart, D D
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Muotka, T
    Naiman, R J
    Pringle, C
    Reuss, M
    van Wilgen, B
    Perspective: The challenge of ecologically sustainable water management2006Ingår i: Water Policy, Vol. 8, s. 475-479Artikel i tidskrift (Refereegranskat)
  • 3. Dangles, O
    et al.
    Jonsson, M
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi och geovetenskap.
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi och geovetenskap.
    The importance of detritivore species diversity for maintaining stream ecosystem functioning following the invasion of a riparian plant2002Ingår i: Biological Invasions, Vol. 4, s. 441-446Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The strength of linkages between riparian plants and stream communities can be expected to be influenced by invading plants. While most studies so far have been focussed on the effects of the leaf litter quality of the invader, this study addresses the impact of detritivores on the pool of detritus. In a natural setting, we found that species richness of shredding macroinvertebrates significantly influenced the breakdown rate of an invasive weed species, the Japanese knotweed (Fallopia japonica), which has become a major plant invader along streams and rivers in Europe and North America. Our findings imply that a reduction of the diversity of shredder species, which may be the result of disturbances, could negatively influence stream ecosystems'' capacity of processing knotweed leaves. Although the knotweed showed breakdown rates similar to those of common native tree and shrub species, other exotic leaf species might show considerably slower rates and hence have greater consequences for the ecosystems. We have, in this study, indicated a technique by which the effects of other non-indigenous plants on ecosystem functioning might be considered.

  • 4. Dangles, O
    et al.
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Species richness-decomposition relationships depend on species dominance2004Ingår i: Ecology Letters, Vol. 7, s. 395-402Artikel i tidskrift (Refereegranskat)
  • 5. Dangles, O
    et al.
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Laudon, H
    Naturally acid freshwater ecosystems are diverse and functional: evidence from boreal streams2004Ingår i: Oikos, Vol. 104, s. 149-155Artikel i tidskrift (Refereegranskat)
  • 6.
    Frainer, André
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    McKie, Brendan
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    When does diversity matter?: Species functional diversity and ecosystem functioning across habitats and seasons in a field experiment2014Ingår i: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 83, nr 2, s. 460-469Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite ample experimental evidence indicating that biodiversity might be an important driver of ecosystem processes, its role in the functioning of real ecosystems remains unclear. In particular, the understanding of which aspects of biodiversity are most important for ecosystem functioning, their importance relative to other biotic and abiotic drivers, and the circumstances under which biodiversity is most likely to influence functioning in nature, is limited. We conducted a field study that focussed on a guild of insect detritivores in streams, in which we quantified variation in the process of leaf decomposition across two habitats (riffles and pools) and two seasons (autumn and spring). The study was conducted in six streams, and the same locations were sampled in the two seasons. With the aid of structural equations modelling, we assessed spatiotemporal variation in the roles of three key biotic drivers in this process: functional diversity, quantified based on a spe- cies trait matrix, consumer density and biomass. Our models also accounted for variability related to different litter resources, and other sources of biotic and abiotic variability among streams. All three of our focal biotic drivers influenced leaf decomposition, but none was important in all habitats and seasons. Functional diversity had contrasting effects on decomposition between habitats and seasons. A positive relationship was observed in pool habitats in spring, associated with high trait dispersion, whereas a negative relationship was observed in riffle habitats during autumn. Our results demonstrate that functional biodiversity can be as significant for functioning in natural ecosystems as other important biotic drivers. In particular, variation in the role of functional diversity between seasons highlights the importance of fluctuations in the relative abundances of traits for ecosystem process rates in real ecosystems.

  • 7. Giller, P S
    et al.
    Hillebrand, H
    Berninger, U-G
    Gessner, M O
    Hawkins, S
    Inchausti, P
    Inglis, C
    Leslie, H
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Monaghan, M T
    Morin, P J
    O’Mullan, G
    Biodiversity effects on ecosystem functioning: emerging issues and their experimental test in aquatic environments2004Ingår i: Oikos, Vol. 104, s. 423-436Artikel i tidskrift (Refereegranskat)
  • 8. Göthe, Emma
    et al.
    Lepori, Fabio
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Forestry affects food webs in northern Swedish coastal streams2009Ingår i: Fundamental and Applied Limnology, ISSN 1863-9135, Vol. 175, nr 4, s. 281-294Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigated how riparian logging affects the food webs of coastal streams in northern Sweden by comparing streams surrounded either by clear-cuts or old-growth forests. Specific hypotheses were that: (i) algal standing stocks are higher in clear-cut streams, whereas detrital standing stocks are higher in old-growth streams; (ii) algal-based (autotrophic) pathways contribute more to consumer (aquatic insect) body carbon in clear-cut streams than in old-growth streams; (iii) a higher autotrophic contribution reflects a combination of numerical (increased abundance of herbivore taxa) and functional (shift in diet by generalist taxa) responses of insect taxa to logging; and (iv) potential predators function more strictly as true predators, and reduce propensity to omnivory in clear-cut relative to old-growth streams. The standing stocks of algae and fine particulate organic matter (FPOM) were similar between treatments, whereas the standing stock of coarse particulate organic matter (CPOM) was higher in old-growth streams. Stable isotope analysis suggested that the autochthonous contribution to aquatic insect carbon per individual taxon was greater in clear-cut than in old-growth streams; although the difference was not statistically conclusive the large effect size suggests that it is biologically meaningful. Greater reliance on autotrophic pathways in clear-cut streams seemed to be caused by a decrease in the relative consumption of detritus by the generalist species Leuctra hippopus, an increase in the abundance of the specialist herbivore Baetis rhodani, and a diffuse increase in the consumption of algae across all functional feeding groups except gathering-collectors. Resources and consumers were enriched in (15)N in clear-cut relative to old-growth streams, suggesting that forestry affects the microbial processing of organic nitrogen, which in turn causes an increased availability of (15)N to algae. The enrichment in (15)N in clear-cut relative to old-growth streams was apparent in all functional feeding groups except for gathering-collectors. In summary, our results show that riparian logging affects the balance of aquatic vs. terrestrial carbon sources and the cycling of nutrients in streams, with effects reverberating to the aquatic consumers.

  • 9. Hellgren, O
    et al.
    Bensch, S
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Bird hosts, blood parasites and their vectors--associations uncovered by molecular analyses of blackfly blood meals.2008Ingår i: Molecular Ecology, ISSN 1365-294X, Vol. 17, nr 6, s. 1605-13Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The level of host specificity of blood-sucking invertebrates may have both ecological and evolutionary implications for the parasites they are transmitting. We used blood mealsfrom wild-caught blackflies for molecular identification of parasites and hosts to examine patterns of host specificity and how these may affect the transmission of avian blood parasites of the genus Leucocytozoon. We found that five different species of ornithophilic blackflies preferred different species of birds when taking their blood meals. Of the blackflies that contained avian blood meals, 62% were infected with Leucocytozoon parasites, consisting of 15 different parasite lineages. For the blackfly species, there was a significant association between the host width (measured as the genetic differentiation between the used hosts) and the genetic similarity of the parasites in their blood meals. The absence of similar parasite in blood meals from blackflies with different host preferences is interpreted as a result of the vector–host associations. The observed associations between blackfly species and host species are therefore likely to hinder parasites to be transmitted between different host-groups, resulting in ecologically driven associations between certain parasite lineages and hosts species.

  • 10. Hladyz, Sally
    et al.
    Åbjörnsson, Kajsa
    Chauvet, Eric
    Dobson, Michael
    Elosegi, Arturo
    Ferreira, Verónica
    Fleituch, Tadeusz
    Gessner, Mark O
    Giller, Paul S
    Gulis, Vladislav
    Hutton, Stephen A
    Lacoursière, Jean O
    Lamothe, Sylvain
    Lecerf, Antoine
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    McKie, Brendan G
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Nistorescu, Marius
    Preda, Elena
    Riipinen, Miira P
    Rîşnoveanu, Geta
    Schindler, Markus
    Tiegs, Scott D
    Vought, Lena B-M
    Woodward, Guy
    Stream ecosystem functioning in an agricultural landscape: the importance of terrestrial-aquatic linkages2011Ingår i: Ecosystems in a human-modified landscape: a european perspective / [ed] Guy Woodward, Amsterdam: Academic Press, 2011, Vol. 44, s. 211-276Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    The loss of native riparian vegetation and its replacement with non-native species or grazing land for agriculture is a worldwide phenomenon, but one that is prevalent in Europe, reflecting the heavily-modified nature of the continent’s landscape. The consequences of these riparian alterations for freshwater ecosystems remain largely unknown, largely because bioassessment has traditionally focused on the impacts of organic pollution on community structure. We addressed the need for a broader perspective, which encompasses changes at the catchment scale, by comparing ecosystem processes in woodland reference sites with those with altered riparian zones. We assessed a range of riparian modifications, including clearance for pasture and replacement of woodland with a range of low diversity plantations, in 100 streams to obtain a continental-scale perspective of the major types of alterations across Europe. Subsequently, we focused on pasture streams, as an especially prevalent widespread riparian alteration, by characterising their structural (e.g. invertebrate and fish communities) and functional (e.g. litter decomposition, algal production, herbivory) attributes in a country (Ireland) dominated by this type of landscape modification, via field and laboratory experiments. We found that microbes became increasingly important as agents of decomposition relative to macrofauna (invertebrates) in impacted sites in general and in pasture streams in particular. Resource quality of grass litter (e.g., carbon : nutrient ratios, lignin and cellulose content) was a key driver of decomposition rates in pasture streams. These systems also relied more heavily on autochthonous algal production than was the case in woodland streams, which were more detrital based. These findings suggest that these pasture streams might be fundamentally different from their native, ancestral woodland state, with a shift towards greater reliance on autochthonous-based processes. This could have a destabilizing effect on the dynamics of the food web relative to the slower, detrital-based pathways that dominate in woodland streams.

  • 11. Hughes, S J
    et al.
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Atlantic island freshwater ecosystems: challenges and considerations following the EU Water Framework Directive2005Ingår i: Hydrobiologia, Vol. 544, s. 289-297Artikel i tidskrift (Refereegranskat)
  • 12. Ilmonen, Jari
    et al.
    Adler, Peter H
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Cywinska, Alina
    The Simulium vernum group (Diptera: Simuliidae) in Europe: multiple character sets for assessing species status2009Ingår i: Zoological Journal of the Linnean Society, ISSN 0024-4082, E-ISSN 1096-3642, Vol. 156, nr 4, s. 847-863Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The value of using characters from multiple sources - chromosomes, ecology, gene sequences, and morphology - to evaluate the species status of closely related black flies is demonstrated for three European members of the Simulium vernum group: Simulium crenobium (Knoz, 1961), Simulium juxtacrenobium Bass & Brockhouse, 1990, and Simulium vernum s.s. Macquart, 1826. Simulium juxtacrenobium is a chromosomally, molecularly, and morphologically distinct species that diverged from S. crenobium and S. vernum s.s. about 2 Mya. It is specialized for intermittent streams, is univoltine, and is recorded for the first time from northern Europe, based on collections from Finland and Sweden, representing a range extension of about 1800 km. In contrast, S. crenobium, although confirmed as a distinct species, differs from S. vernum s.s. by only a few larval and chromosomal characters, and by a breeding habitat restricted to mountain spring brooks. Whereas all four character sets independently support the specific distinctness of S. juxtacrenobium and S. vernum s.s., multiple character sets are required to establish the specific validity of S. crenobium.

  • 13.
    Jansson, Roland
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Nilsson, Christer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Restoring freshwater ecosystems in riverine landscapes: the roles of connectivity and recovery processes2007Ingår i: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 52, nr 4, s. 589-596Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1. This paper introduces key messages from a number of papers emanating from the Second International Symposium on Riverine Landscapes held in August 2004 in Sweden, focusing on river restoration. Together these papers provide an overview of the science of river restoration, and point out future research needs.

    2. Restoration tests the feasibility of recreating complex ecosystems from more simple and degraded states, thereby presenting a major challenge to ecological science. Therefore, close cooperation between practitioners and scientists would be beneficial, but most river restoration projects are currently performed with little or no scientific involvement.

    3. Key messages emanating from this series of papers are: The scope, i.e. the maximum and minimum spatial extent and temporal duration of habitat use, of species targeted for restoration should be acknowledged, so that all relevant stages in their life cycles are considered. Species that have been lost from a stream cannot be assumed to recolonise spontaneously, calling for strategies to ensure the return of target species to be integrated into projects. Possible effects of invasive exotic species also need to be incorporated into project plans, either to minimise the impact of exotics, or to modify the expected outcome of restoration in cases where extirpation of exotics is impractical.

    4. Restoration of important ecological processes often implies improving connectivity of the stream. For example, longitudinal and lateral connectivity can be enhanced by restoring fluvial dynamics on flood-suppressed rivers and by increasing water availability in rivers subject to water diversion or withdrawal, thereby increasing habitat and species diversity. Restoring links between surface and ground water flow enhances vertical connectivity and communities associated with the hyporheic zone.

    5. Future restoration schemes should consider where in the catchment to locate projects to make restoration most effective, consider the cumulative effects of many small projects, and evaluate the potential to restore ecosystem processes under highly constrained conditions such as in urban areas. Moreover, restoration projects should be properly monitored to assess whether restoration has been successful, thus enabling adaptive management and learning for the future from both successful and unsuccessful restorations.

  • 14.
    Jonsson, M
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Species richness and composition effects in a detrital processing chain2005Ingår i: Journal of The North American Benthological Society, ISSN 0887-3593, E-ISSN 1937-237X, Vol. 24, s. 798-806Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several studies in the past decade have shown that rates of ecosystem processes may be affected by the number of species involved in the processes. However, how products, such as frass and feces, that are derived from those processes indirectly affect other functional feeding groups (FFGs) and whether such effects vary with species number are not well understood. We manipulated presence/absence and species richness of shredding larval stoneflies in laboratory microcosms containing leaf litter to test whether the number of species affected the growth of suspension-feeding black fly larvae. The presence of shredders increased the production of particles (>0.1 mm) and contributed to 30 to 56% higher black fly growth than in the absence of shredders. In addition, species richness and composition of shredders significantly affected black fly growth. Thus, our results show that species richness and composition in one FFG may affect FFGs further down the processing chain, most likely via effects on both quantity and size distribution of products derived from the process.

  • 15.
    Jonsson, Micael
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi och geovetenskap.
    Dangles, O
    Malmqvist, B.
    Guérold, F.
    Simulating species loss following perturbation: assessing the effects on process rates2002Ingår i: Proceedings of the Royal Society London B, Vol. 269, s. 1047-1052Artikel i tidskrift (Refereegranskat)
  • 16.
    Jonsson, Micael
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Deleu, Pieter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Persisting effects of river regulation on emergent aquatic insects and terrestrial invertebrates in upland forests2013Ingår i: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 29, nr 5, s. 537-547Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    River regulation can alter the structural complexity and natural dynamics of river ecosystems substantially with negative consequences for aquatic insects. However, there have been few studies of regulation effects on the export of emergent insects into terrestrial ecosystems. In northern Scandinavia, we compared emerged aquatic insect and terrestrial invertebrate biomass between four strongly regulated and four free-flowing rivers using fortnightly measurements at three upland-forest blocks in each over one summer. The biomass of emerged aquatic insects was significantly lower along regulated rivers than free-flowing rivers. Biomass in Linyphiidae, Opiliones, Staphylinidae, total Coleoptera, Formicidae and total terrestrial invertebrates was also lower along regulated rivers. Aquatic insect biomass did not explain the entire regulation effect on terrestrial invertebrates but did explain significant variations among Linyphiidae, total Coleoptera, Formicidae and total terrestrial biomass. Variations in Formicidae also explained significant variance among several terrestrial taxa, suggesting some keystone role in this group. Overall, our results suggest that river regulation affects upland-forest invertebrate communities, with at least some of these effects arising from links between aquatic emergence and terrestrial predators. The data highlight the need to consider areas beyond the riparian zone when assessing the effects of river regulation. Copyright (c) 2012 John Wiley & Sons, Ltd.

  • 17.
    Jonsson, Micael
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi och geovetenskap.
    Malmqvist, B.
    Ecosystem process rate increases with animal species richness: evidence from leaf-eating, aquatic insects2000Ingår i: Oikos, Vol. 89, s. 519-523Artikel i tidskrift (Refereegranskat)
  • 18.
    Jonsson, Micael
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi och geovetenskap.
    Malmqvist, B.
    Importance of species identity and number for process rates within stream macroinvertebrate functional feeding groups2003Ingår i: Journal of Animal Ecology, Vol. 72, s. 453-459Artikel i tidskrift (Refereegranskat)
  • 19.
    Jonsson, Micael
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi och geovetenskap.
    Malmqvist, B.
    Hoffsten, P.-O.
    Leaf litter breakdown in boreal streams: does shredder species richness matter?2001Ingår i: Freshwater Biology, Vol. 46, s. 161-171Artikel i tidskrift (Refereegranskat)
  • 20.
    Jonsson, Micael
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Mechanisms behind positive diversity effects on ecosystem functioning: testing the facilitation and interference hypotheses2003Ingår i: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 134, nr 4, s. 554-559Artikel i tidskrift (Refereegranskat)
  • 21.
    Jonsson, Micael
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Strasevicius, Darius
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Influences of river regulation and environmental variables on upland bird assemblages in northern Sweden2012Ingår i: Ecological research, ISSN 0912-3814, E-ISSN 1440-1703, Vol. 27, nr 5, s. 945-954Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most large rivers in Sweden are regulated to produce hydropower. This transformation from free-flowing rivers to chains of elongate run-of-river impoundments has been shown to have consequences for aquatic, riparian and adjacent upland environments, and for the emergence patterns of aquatic insects that are important for terrestrial consumers. In this study, we investigated bird assemblages in upland-forest environments along seven large rivers (three heavily impounded and four free flowing) in northern Sweden. Bird densities were assessed by point counts in the breeding and post-breeding seasons. While we observed no significant differences in bird species richness between regulated and free-flowing rivers, cumulative densities of two feeding groups of birds (those feeding on seeds and/or large insects and those feeding on small insects) were higher along free-flowing rivers than along regulated rivers in the breeding season, consistent with known differences in aquatic-insect emergence. Further, ordination analyses showed seasonal shifts in bird assemblage structure, and that these shifts differed between regulated and free-flowing rivers and between the two feeding groups. However, the variables explaining the most variance (11-28 %) in bird assemblage structure were related to a gradient of agricultural-to-forest land use. River regulation contributed to the model in the post-breeding season, but was of relatively low importance. Nevertheless, the observed contrasting seasonal shifts in upland-forest bird assemblage structure between regulated and free-flowing rivers suggest that regulation-induced modifications of aquatic-insect emergence and subsequent changes in prey availability to the birds are also important considerations.

  • 22.
    Lepori, F
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Gaul, D
    Palm, D
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Food-web responses to restoration of channel heterogeneity in boreal streams2006Ingår i: Canadian J. of Fisheries and Aquatic Sciences, Vol. 63, s. 2478-2486Artikel i tidskrift (Refereegranskat)
  • 23.
    Lepori, F
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Palm, D
    Brännäs, E
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Does restoration of structural heterogeneity in streams enhance fish and macroinvertebrate diversity?2005Ingår i: Ecological Applications, Vol. 15, s. 2060-2071Artikel i tidskrift (Refereegranskat)
  • 24.
    Lepori, F
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Palm, D
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Effects of stream restoration on ecosystem functioning: detritus retentiveness and decomposition2005Ingår i: Journal of Applied Ecology, Vol. 42, s. 228-238Artikel i tidskrift (Refereegranskat)
  • 25.
    Lepori, Fabio
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Deterministic control on community assembly peaks at intermediate levels of disturbance2009Ingår i: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 118, nr 3, s. 471-479Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite long-standing research, the processes that drive community assembly remain poorly understood. We censused macroinvertebrate communities and measured flood disturbance in 17 Scandinavian mountain streams to assess the hypothesis that communities are shaped by stochastic processes under stable conditions, and increasingly by deterministic processes as disturbance becomes more severe. Each study stream was categorized as being stable (n=5), intermediate (n=7), or disturbed (n=5) depending on the severity of scouring floods. Following spring floods, the number of potential colonisers decreased with increasing disturbance, suggesting that disturbance filtered out species unable to cope with the stress involved. Communities at stable sites had the highest beta diversity, indicating that stochastic processes of community assembly were most important under the least disturbed conditions. In partial contrast with our predictions, the lowest beta diversity occurred between intermediate (not disturbed) sites, suggesting that increasing disturbance first enhances determinism but then rekindles stochasticity at severity levels beyond intermediate. Macroinvertebrate communities were shaped by deterministic processes, which recruit potential regional colonists depending on niche differences and disturbance conditions and by stochastic processes, which distribute the selected species randomly among individual localities. Although often considered opposing, stochastic and deterministic processes interact hierarchically, with relative strength modified by disturbance.

  • 26.
    Lepori, Fabio
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Predictable changes in trophic community structure along a spatial disturbance gradient in streams2007Ingår i: Freshwater Biology, Vol. 52, s. 2184-2195Artikel i tidskrift (Refereegranskat)
  • 27.
    Malmqvist, B
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Adler, P H
    Kuusela, K
    Merritt, R W
    Wotton, R S
    Black flies in the boreal biome, key organisms in both terrestrial and aquatic environments: A review2004Ingår i: Ecoscience, Vol. 11, s. 187-200Artikel i tidskrift (Refereegranskat)
  • 28.
    Malmqvist, B
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Adler, P H
    Strasevicius, D
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Testing hypotheses on egg number and size in black flies (Diptera: Simuliidae)2004Ingår i: Journal of Vector Ecology, Vol. 29, s. 248-256Artikel i tidskrift (Refereegranskat)
  • 29.
    Malmqvist, Björn
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Strasevicius, Darius
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Adler, P H
    Catches of bloodsucking blackflies (Diptera: Simuliidae) tell different stories depending on sampling method2007Ingår i: Entomologica Fennica, Vol. 18, s. 110-116Artikel i tidskrift (Refereegranskat)
  • 30. Malmqvist, Björn
    et al.
    Strasevicius, Darius
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Adler, Peter H.
    Transfer to terrestrial ecosystems of an important aquatic insect prey and parasite vector decreases following human impactManuskript (Övrigt vetenskapligt)
  • 31.
    Malmqvist, Björn
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Strasevicius, Darius
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Hellberg, Olof
    Adler, Peter H.
    Bensch, Staffan
    Vertebrate host specificity of wild-caught blackflies revealed by mitochondrial DNA in blood2004Ingår i: Proceedings of the Royal Society Biology Letters Supplement, ISSN 0962-8452, Vol. 271, nr Supp. 4, s. S152-S155Artikel i tidskrift (Refereegranskat)
  • 32.
    McKie, BG
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Assessing ecosystem functioning in streams affected by forest management: increased leaf decomposition occurs without changes to the composition of benthic assemblages2009Ingår i: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 54, nr 10, s. 2086-2100Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1. Landscape management practices that alter energetic linkages between aquatic and terrestrial habitats can affect associated ecosystem processes, and ultimately the provision of ecosystem services of importance to humanity. Such effects cannot always be inferred from current biomonitoring schemes, which are typically based on assessment of community structural parameters rather than functional attributes related to important ecosystem-level processes.

    2. We investigated effects of forest clearcutting, a major landscape-level disturbance known to alter the energetic basis of aquatic food webs, on headwater streams in northern Sweden. The key ecosystem process of leaf decomposition was measured as an index of ecosystem functioning. The biomass of detritivorous shredders was also quantified, along with various community structural parameters associated with the diversity, composition and functional guild organisation of benthic macroinvertebrate assemblages.

    3. No differences in macroinvertebrate abundance, diversity or assemblage composition were detected between forested and clearcut streams, and most functional guilds were similarly unaffected, though species density of scrapers was higher in forested than clearcut channels.

    4. In contrast, mass loss of two leaf species was elevated in all clearcut streams, with evidence for increases in the efficiency per degree-day of both the microbial and detritivore mediated fractions of decomposition.

    5.  Increased rates of leaf mass loss in the clearcut streams were associated with greater phosphate concentrations and shredder biomass, and with an increased relative abundance of broadleaves in standing stocks of benthic litter. Together, these findings indicate a more rapid transfer of energy and nutrients through the detrital pathways of our clearcut streams.

    6. These results demonstrate the utility of litter decomposition assays for monitoring effects of forest management on stream ecosystem functioning, and have implications for nutrient cycles in landscapes extensively influenced by forest management. The markedly different responses of our functional and structural measures to clearcutting highlight the value of incorporating methods for the functional assessment of ecosystems into biomonitoring schemes.

  • 33.
    McKie, Brendan G.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Petrin, Zlatko
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Mitigation or disturbance? Effects of liming on macroinvertebrate assemblage structure and leaf-litter decomposition in the humic streams of northern Sweden2006Ingår i: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 43, nr 4, s. 780-791Artikel i tidskrift (Refereegranskat)
    Abstract [en]
    1. Stream liming can alleviate the effects of anthropogenic acidification but itself constitutes a substantial ecosystem-level perturbation. Acidity in the humic streams of northern Sweden largely arises from natural causes but liming is extensively practised, with uncertain ecological outcomes.
    2. We investigated macroinvertebrate assemblage structure and leaf-litter decomposition in seven humic Swedish streams, each of which is limed at a single point using a dosing tower. Grey alder Alnus incana leaves were enclosed in replicate fine (mesh size 0·5 mm) and coarse (10 mm) mesh bags at three locations in each stream: upstream of the dosing tower, in the transitional ‘mixing zone’ immediately downstream of the tower, and at a site further downstream where the lime powder is completely dissolved, with marked changes to water chemistry. Benthic macroinvertebrate assemblages were characterized from each site via five replicate Surber samples.
    3. Alkalinity, pH, conductivity and calcium (Ca) concentrations increased following liming, whereas dissolved organic carbon and aluminium concentrations decreased.
    4. Decomposition in fine mesh bags, primarily mediated by microbes, was positively associated with pH and Ca and was significantly elevated by liming, probably attributable to stimulation of fungal pectin-degrading enzymes that require Ca as a cofactor.
    5. Decomposition attributable to detritivorous insects (shredders), assessed by subtracting decomposition observed in fine mesh bags from that observed in coarse bags, was reduced following liming, in concert with changes to shredder assemblages. Abundance of large caddisfly shredders declined in limed stream sections, whereas some smaller stoneflies increased in number. Shredder diversity declined following liming during spring. Species evenness fell overall, and richness was reduced in four of six streams.
    6. Synthesis and applications. Water chemistry changes following stream liming in northern Sweden appear to overcompensate for the limited acid deposition observed in the region, with important ecosystem consequences. The potential deleterious impacts of liming need to be balanced against its desired outcomes in regions where acidity is largely attributable to natural causes.
  • 34.
    McKie, Brendan G
    et al.
    Department of Aquatic Sciences and Assessment, SLU, Uppsala, Sweden.
    Schindler, Markus
    Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, and Institute of Integrative Biology (IBZ), ETH Zurich, 6047 Kastanienbaum, Switzerland.
    Gessner, Mark O
    Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, and Institute of Integrative Biology (IBZ), ETH Zurich, 6047 Kastanienbaum, Switzerland.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Placing biodiversity and ecosystem functioning in context: environmental perturbations and the effects of species richness in a stream field experiment2009Ingår i: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 160, nr 4, s. 757-770Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Greater biodiversity is often associated with increased ecosystem process rates, and is expected to enhance the stability of ecosystem functioning under abiotic stress. However, these relationships might themselves be altered by environmental factors, complicating prediction of the effects of species loss in ecosystems subjected to abiotic stress. In boreal streams, we investigated effects of biodiversity and two abiotic perturbations on three related indices of ecosystem functioning: leaf decomposition, detritivore leaf processing efficiency (LPE) and detritivore growth. Replicate field enclosures containing leaves and detritivore assemblages were exposed to liming and nutrient enrichment, raising pH and nutrient levels. Both treatments constitute perturbations for our naturally acidic and nutrient-poor streams. We also varied detritivore species richness and density. The effects of the abiotic and diversity manipulations were similar in magnitude, but whereas leaf decomposition increased by 18% and 8% following liming and nutrient enrichment, respectively, increased detritivore richness reduced leaf decomposition (6%), detritivore LPE (19%) and detritivore growth (12%). The detritivore richness effect on growth was associated with negative trait-independent complementarity, indicating interspecific interference competition. These interactions were apparently alleviated in both enriched and limed enclosures, as trait-independent complementarity became less negative. LPE increased with detritivore density in the monocultures, indicating benefits of intra-specific aggregation that outweighed the costs of intra-specific competition, and dilution of these benefits probably contributed to lowered leaf decomposition in the species mixtures. Finally, the effects of liming were reduced in most species mixtures relative to the monocultures. These results demonstrate how environmental changes might regulate the consequences of species loss for functioning in anthropogenically perturbed ecosystems, and highlight potential influences of biodiversity on functional stability. Additionally, the negative effects of richness and positive effects of density in our field study were opposite to previous laboratory observations, further illustrating the importance of environmental context for biodiversity-ecosystem functioning relationships.

  • 35.
    McKie, Brendan
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Woodward, G
    Hladyz, S
    Nistorescu, M
    Preda, E
    Popescu, C
    Giller, P S
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Ecosystem functioning in stream assemblages from different regions: contrasting responses to variation in detritivore richness, evenness and density.2008Ingår i: Journal of Animal Ecology, ISSN 1365-2656, Vol. 77, nr 3, s. 495-504Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1. The diversity of species traits characterising a biological assemblage reflects not only its species richness but also its species evenness and total density, which together influence the concentration of traits within functional guilds, and is ultimately constrained by the regional species pool. Implications of such variation for spatio-temporal variability in biodiversity-ecosystem functioning relationships are potentially complex, but poorly understood.

    2. In separate microcosm experiments maintained at laboratories in Sweden, Romania and Ireland, we investigated effects of the species richness, evenness and density of stream-living detritivores on two related processes: detritivore leaf processing efficiency (LPE) and growth. Assemblage composition varied among the laboratories, with only one taxonomic order (Plecoptera) investigated in Sweden, whereas two orders, encompassing wider trait variation, were studied in Romania (Trichoptera and Plecoptera) and Ireland (Trichoptera and Isopoda).

    3. Relationships between density and both LPE and growth ranged from negative to positive across all the study species, highlighting the potential for density-dependent variation in process rates to alter ecosystem functioning, but indicating that such effects vary with species identity.

    4. Increased diversity was associated with 25-50% higher LPE in the two more heterogeneous assemblages, but whereas LPE in the Romanian study was generally enhanced as richness increased, LPE in the Irish study only increased in less even species mixtures dominated by particular species. Mechanisms underlying these diversity effects also contrasted. The Romanian results were predominantly attributable to the selection effect, whereas there was evidence for positive complementarity among species in Ireland.

    5. Growth was elevated in Romanian species mixtures, reflecting positive complementarity among species, but lower than expected growth in some Swedish mixtures was associated with negative complementarity.

    6. Our results emphasize the potential importance of detritivore diversity for stream ecosystem functioning across multiple contrasting assemblages, but variability in both the effects of diversity on the studied processes, and the mechanisms underlying those effects, highlight challenges in generalizing impacts of diversity change for the functional integrity of naturally dynamic stream ecosystems in situ.

  • 36. Meissner, Kristian
    et al.
    Juntunen, Antti
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Muotka, Timo
    Predator-prey interactions in a variable environment: responses of a caddis larva and its blackfly prey to variations in stream flow2009Ingår i: Annales Zoologici Fennici, ISSN 0003-455X, E-ISSN 1797-2450, Vol. 46, nr 3, s. 193-204Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Predator-prey studies in streams have traditionally focused on mayfly-stonefly interactions in relatively constant flow conditions. In reality, however, lotic prey encounter multiple types of predators, most of which are restricted to low-velocity microhabitats. By contrast, some invertebrate prey may occur in very high current velocities. For example, many blackfly species are able to feed at velocities of 100 cm s(-1), whereas even moderate currents reduce the hunting efficiency of their invertebrate predators. The caddisfly larvae of the genus Rhyacophila, however, may be an exception to the pattern of reducing predator efficiency with increasing velocity. Using a combination of laboratory and field experiments and behavioral field observations, we examined the interaction between predatory Rhyacophila caddis larvae and larval blackflies along a velocity gradient of 20-120 cm s(-1). In laboratory experiments, Rhyacophila preferred currents slower than 50 cm s(-1) while blackflies exhibited a wide tolerance of currents and frequently occurred in currents exceeding 100 cm s(-1). In direct field observations, total activity and distance moved by Rhyacophila were similar at all current velocity regimes tested, but frequency of predation attempts on blackflies was lowest at the highest velocities (> 100 cm s(-1)). In a field colonization study, blackflies avoided substrates with the slowest velocities (< 40 cm s(-1)), as also did the caddis larvae. Only velocities approaching 100 cm s(-1) provide blackflies with refuge from predation by Rhyacophila. Being able to maneuver across a wide range of velocities, Rhyacophila may have more pervasive effects on their prey than other lotic invertebrate predators.

  • 37.
    Nilsson, Christer
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Jansson, Roland
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Naiman, Robert J
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Restoring Riverine Landscapes: the Challenge of Identifying Priorities, Reference States, and Techniques2007Ingår i: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 12, nr 1, s. 16-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This special issue of Ecology and Society on restoring riverine landscapes draws together nine presentations from the Second International Symposium on Riverine Landscapes, convened in August 2004 in Storforsen, Sweden. We summarize three themes related to river restoration: (1) setting priorities, (2) identifying relevant reference conditions, and (3) choosing appropriate techniques. We discuss ways of developing river restoration and provide examples of future needs in sustaining functioning river ecosystems that can support human societies.

  • 38.
    Nilsson, Christer
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Lepori, Fabio
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Törnlund, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Hjerdt, Niklas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Hjerdt, James M.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Palm, Daniel
    Department of Aquaculture, SLU.
    Östergren, Johan
    Department of Aquaculture, SLU.
    Jansson, Roland
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Brännäs, Eva
    Department of Aquaculture, SLU.
    Lundqvist, Hans
    Department of Aquaculture, SLU.
    Forecasting environmental responses to restoration of rivers used as log floatways: an interdisciplinary challenge2005Ingår i: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 8, nr 7, s. 779-800Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Log floating in the 19th to mid 20th centuries has profoundly changed the environmental conditions in many northern river systems of the world. Regulation of flow by dams, straightening and narrowing of channels by various piers and wing dams, and homogenization of bed structure are some of the major impacts. As a result, the conditions for many riverine organisms have been altered. Removing physical constructions and returning boulders to the channels can potentially restore conditions for these organisms. Here we describe the history of log driving, review its impact on physical and biological conditions and processes, and predict the responses to restoration. Reviewing the literature on comparable restoration efforts and building upon this knowledge, using boreal Swedish rivers as an example, we address the last point. We hypothesize that restoration measures will make rivers wider and more sinuous, and provide rougher bottoms, thus improving land-water interactions and increasing the retention capacity of water, sediment, organic matter and nutrients. The geomorphic and hydraulic/hydrologic alterations are supposed to favor production, diversity, migration and reproduction of riparian and aquatic organisms. The response rates are likely to vary according to the types of processes and organisms. Some habitat components, such as beds of very large boulders and bedrock outcrops, and availability of sediment and large woody debris are believed to be extremely difficult to restore. Monitoring and evaluation at several scales are needed to test our predictions.

  • 39. Perkins, Daniel M.
    et al.
    Mckie, Brendan G.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Gilmour, Steven G.
    Reiss, Julia
    Woodward, Guy
    Environmental Warming and Biodiversity-Ecosystem Functioning in Freshwater Microcosms: Partitioning the Effects of Species Identity, Richness and Metabolism2010Ingår i: Integrative Ecology: From Molecules to Ecosystems / [ed] Guy Woodward, School of Biological and Chemical Sciences, Queen Mary University of London, London, Academic Press, 2010, s. 177-209Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Predicting the effects of global warming on biodiversity–ecosystem functioning (B–EF) relationships is complicated by potential interactions among abiotic and biotic variables at multiple levels of organisation, including adaptation within regional species populations and changes in community composition and species richness. We investigated the capacity for assemblages of three freshwater invertebrate consumer species (Asellus aquaticusNemoura cinerea and Sericostoma personatum) from temperate (southern England) and boreal (northern Sweden) regions to respond to expected shifts in temperature and basal resources, and quantified rates of a key ecosystem process (leaf-litter decomposition). Predictions of assemblage metabolism, derived from allometric-body size and temperature scaling relationships, accounted for approximately 40% of the variance in decomposition rates. Assemblage species composition accounted for further variance, but species richness per se had no discernible effect. Regional differences were evident in rates of leaf decomposition across temperature and resource manipulations, and in terms of the processing efficiency of temperate and boreal consumers of the same species (i.e. after correcting for body size and metabolic capacity), suggesting that intraspecific variation among local populations could modulate B–EF effects. These differences have implications for extrapolating how environmental warming and other aspects of climate change (e.g. species range shifts) might affect important drivers of ecosystem functioning over large biogeographical scales.

  • 40.
    Petrin, Zlatko
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Englund, Göran
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Contrasting effects of anthropogenic and natural acidity in streams: a meta-analysis.2008Ingår i: Proceedings of the Royal Society B: Biological Sciences, ISSN 0962-8452, Vol. 275, nr 1639, s. 1143-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    arge-scale human activities including the extensive combustion of fossil fuels have caused acidification of freshwater systems on a continental scale, resulting in reduced species diversity and, in some instances, impaired ecological functioning. In regions where acidity is natural, however, species diversity and functioning seem less affected. This contrasting response is likely to have more than one explanation including the possibility of adaptation in organisms exposed to natural acidity over evolutionary timescales and differential toxicity due to dissimilarities in water chemistry other than pH. However, empirical evidence supporting these hypotheses is equivocal. Partly, this is because previous research has mainly been conducted at relatively small geographical scales, and information on ecological functioning in this context is generally scarce. Our goal was to test whether anthropogenic acidity has stronger negative effects on species diversity and ecological functioning than natural acidity. Using a meta-analytic approach based on 60 data sets we show that macroinvertebrate species richness and the decomposition of leaf litter - an important process in small streams - tend to decrease with increasing acidity across regions and across both acidity categories. Macroinvertebrate species richness, however, declines three times more rapidly with increasing acidity where it is anthropogenic than where it is natural, in agreement with the adaptation hypothesis and the hypothesis of differences in water chemistry. In contrast, the loss in ecological functioning differs little between categories, probably because increases in the biomass of taxa remaining at low pH compensate for losses in functionality that would otherwise accompany losses of taxa from acidic systems. This example from freshwater acidification illustrates how natural and anthropogenic stressors can differ markedly in their effects on species diversity and one aspect of ecological functioning.

  • 41.
    Petrin, Zlatko
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Englund, Göran
    Malmqvist, Björn
    Species richness, but not ecosystem functioning, is lost at a higher rate in recently acidified than in naturally acidic streamsArtikel i tidskrift (Refereegranskat)
  • 42.
    Petrin, Zlatko
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Laudon, Hjalmar
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Diverging effects of anthropogenic acidification and natural acidity on community structure in Swedish streams.2008Ingår i: The Science of the Total Environment, ISSN 0048-9697, Vol. 394, nr 2-3, s. 321-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Anthropogenic acidification caused by aerial deposition of acidifying substances is known to have detrimental effects on freshwater biota, including reductions in species diversity and ecosystem functioning. However, such impairment is not found in systems acidified to a similar extent by natural processes. A proposed explanation for this difference is that freshwater organisms have had far more time to evolve and adapt to natural than anthropogenic acidification. Thus, where acidity is natural, adaptation may account for diverse and functional communities. Here, we investigated whether adaptations – that were previously implied to occur on small spatial scales – may explain the species richness patterns on a much larger geographical scale, apply to ecological functioning, and are relevant in Sweden, where natural acidity is geologically relatively recent. Therefore, we compared differences in species diversity and ecosystem process rates between 24 acidic and circumneutral streams in northern Sweden, where acidity is natural, and southern Sweden, where acidity is largely anthropogenic. In agreement with our predictions, the difference in macroinvertebrate species richness between acidic and circumneutral streams was threefold larger in the region where acidity was anthropogenic than where it was natural, albeit marginally non-significantly. In contrast, no such trend was found for the rates of decomposition by microbes and leaf-feeding macroinvertebrates, possibly due to functional redundancy. The structure of species assemblages differed between acidic and circumneutral sites and between the regions. Our results agree with the notion that freshwater biota are adapted to natural acidity, but competing explanations including other differences in water chemistry and differences in the biogeographical colonization histories may also account for part of the observed patterns. Since naturally acidic environments similar to those in northern Sweden are widespread, we predict that diverse and functionally efficient freshwater communities that are well adapted to such conditions are more common than currently recognized.

  • 43.
    Petrin, Zlatko
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Laudon, Hjalmar
    Malmqvist, Björn
    Do natural acidity and anthropogenic acidification have different effects on species diversity and ecosystem functioning?Manuskript (Övrigt vetenskapligt)
  • 44.
    Petrin, Zlatko
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Laudon, Hjalmar
    Department of Forest Ecology, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Does freshwater macroinvertebrate diversity along a pH-gradient reflect adaptation to low pH?2007Ingår i: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 52, nr 11, s. 2172-2183Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1. The impacts of anthropogenic surface water acidification are much better known than those of natural acidity. Recent studies have indicated biodiversity is not degraded and species composition unaltered in naturally acidic compared to circumneutral watercourses.

    2. Here, we use a geographically extensive dataset comprising sites in more than 200 Swedish streams to test whether the lack of effects on macroinvertebrate species diversity is due to exaptation and adaptation to natural acidity.

    3. To this end, we modelled pH associated with spring flood episodes, which inflict the most challenging hydrochemical conditions to the biota. We compared taxonomic richness and species composition along the modelled pH gradient in northern Sweden, where acidity is largely natural, with southern Sweden, a region influenced by significant anthropogenic acidification.

    4. We found Plecoptera richness did not respond to varying pH either in northern or southern Sweden. Ephemeroptera richness was sensitive to pH in both regions, while that of Trichoptera increased with increasing pH in southern Sweden, but decreased in the north. The taxonomic composition of Plecoptera changed along the pH gradient in both regions, whereas that of Ephemeroptera and Trichoptera changed more strongly with pH in southern Sweden.

    5. Our results support the hypothesis that stream invertebrates are able to tolerate low pH through exaptation or adaptation, but that this capability varies among taxonomic groups.

     

  • 45.
    Petrin, Zlatko
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    McKie, Brendan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Buffam, Ishi
    Department of Forest Ecology, Swedish University of Agricultural Sciences, Umeå.
    Laudon, Hjalmar
    Department of Forest Ecology, Swedish University of Agricultural Sciences, Umeå.
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Landscape-controlled chemistry variation affects communities and ecosystem function in headwater streams2007Ingår i: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 64, nr 11, s. 1563-1572Artikel i tidskrift (Refereegranskat)
    Abstract [sv]

    Nous démontrons que les communautés benthiques d’eau douce de cours d’eau naturellement acides dans des bassins versants boréaux diffèrent selon les caractéristiques du paysage environnant. Bien qu’un pH faible soit normalement associé à des impacts négatifs sur la diversité spécifique et le fonctionnement de l’écosystème, néanmoins dans notre étude, la décomposition par les insectes et les microorganismes, ainsi que l’abondance des insectes consommateurs de feuilles, sont généralement élevées aux valeurs basses de pH et dans les sites humiques influencés par un environnement dominé par les tourbières plutôt que par les forêts. De plus, des expériences de croissance in situ montrent que la survie des deux espèces d’insectes les plus abondantes est supérieure lorsque celles-ci proviennent des sites influencés par les tourbières, ce qui souligne leur tolérance aux pH bas. Toutefois, la diversité spécifique croît généralement en fonction du pH et elle est plus élevée aux sites dominés par les forêts qu’à ceux dominés par les tourbières. Bien que moins diversifiés, les cours d’eau acides et humiques s’avèrent fonctionnels et ils contiennent des peuplements distincts de macroinvertébrés. La diversité et le fonctionnement dans les cours d’eau naturellement acides sont apparemment fortement influencés par les effets du type dominant de paysage sur la chimie de l’eau. En conclusion, les impacts négatifs bien documentés de l’acidité causée par l’activité humaine sur la diversité et le fonctionnement peuvent ne pas s’appliquer à des systèmes naturellement acides qui sont hétérogènes des points de vue chimique et biologique.

  • 46. Presa Abós, C
    et al.
    Lepori, F
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    McKie, B G
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Malmqvist, B
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Aggregation among resource patches can promote coexistence in stream-living shredders2006Ingår i: Freshwater Biology, Vol. 51, s. 545-553Artikel i tidskrift (Refereegranskat)
  • 47. Reeves, W K
    et al.
    Adler, P H
    Rätti, O
    Malmqvist, Björn
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Strasevicius, Darius
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi, miljö och geovetenskap.
    Dasch, G A
    Molecular detection of Trypanosoma (Kinetoplastida: Trypanosomatidae) in black flies (Diptera: Simuliidae)2007Ingår i: Comparative Parasitology, Vol. 74, s. 171-175Artikel i tidskrift (Refereegranskat)
  • 48.
    Strasevicius, Darius
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Jonsson, Micael
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Nyholm, N. Erik I.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Reduced breeding success of Pied Flycatchers Ficedula hypoleuca along regulated rivers2013Ingår i: Ibis, ISSN 0019-1019, E-ISSN 1474-919X, Vol. 155, nr 2, s. 348-356Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most large rivers in northern Sweden are regulated to produce hydropower, with subsequent effects on flow dynamics and aquatic insect communities. Several studies have shown that aquatic and terrestrial systems are intimately connected via the export of emergent aquatic insects, but few have assessed how human modifications of aquatic habitats may influence this connection. We compared breeding success of the insectivorous Pied Flycatcher Ficedula hypoleuca in near-riparian upland forests along two regulated and two free-flowing large rivers in northern Sweden over 3years. The regulated rivers showed lower aquatic insect export to the surroundings, as a consequence of regulation-induced loss of suitable aquatic insect habitats. Survival of Pied Flycatcher nestlings was 1015% greater along the free-flowing rivers. Females breeding near the free-flowing rivers also started egg-laying earlier and with greater synchrony than those at the regulated rivers, and showed a smaller decrease in weight during breeding than did females along the regulated rivers. However, there were no differences in occupation rate, clutch size or number of successfully hatched juveniles between regulated and free-flowing rivers. As regulated rivers showed lower abundance of flying aquatic insects, which may also reduce the abundance of terrestrial invertebrate prey, regulation-induced changes in the export of emergent aquatic insects may explain both directly and indirectly the observed reduction in Pied Flycatcher breeding success along regulated rivers. Large-scale river regulation may therefore impair the breeding success of insectivorous birds through impacts on prey availability.

  • 49.
    Strasevicius, Darius
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Are avian blood parasites reduced because of degraded vector-breeding habitats?Manuskript (Övrigt vetenskapligt)
  • 50.
    Strasevicius, Darius
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Malmqvist, Björn
    Influences of river regulation on upland bird assemblages in northern Sweden.Manuskript (Övrigt vetenskapligt)
12 1 - 50 av 52
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