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Malmqvist, Björn
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Publications (10 of 52) Show all publications
Frainer, A., McKie, B. & Malmqvist, B. (2014). When does diversity matter?: Species functional diversity and ecosystem functioning across habitats and seasons in a field experiment. Journal of Animal Ecology, 83(2), 460-469
Open this publication in new window or tab >>When does diversity matter?: Species functional diversity and ecosystem functioning across habitats and seasons in a field experiment
2014 (English)In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 83, no 2, p. 460-469Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
John Wiley & Sons, 2014
Keywords
stream ecosystems, litter decomposition, species evenness, species traits, spatial-temporal variability, path analyses
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-82868 (URN)10.1111/1365-2656.12142 (DOI)000331469200015 ()
Funder
Swedish Research Council, 621-2006-375
Available from: 2013-11-12 Created: 2013-11-12 Last updated: 2018-06-08Bibliographically approved
Jonsson, M., Deleu, P. & Malmqvist, B. (2013). Persisting effects of river regulation on emergent aquatic insects and terrestrial invertebrates in upland forests. Rivers Research and Applications: an international journal devoted to river research and management, 29(5), 537-547
Open this publication in new window or tab >>Persisting effects of river regulation on emergent aquatic insects and terrestrial invertebrates in upland forests
2013 (English)In: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 29, no 5, p. 537-547Article in journal (Refereed) Published
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.

Keywords
aquatic insects, aquatic subsidies, large rivers, river regulation, river impoundment, Sweden, terrestrial invertebrates, upland forests
National Category
Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-76805 (URN)10.1002/rra.2559 (DOI)000320113900001 ()
Available from: 2013-07-16 Created: 2013-07-15 Last updated: 2018-06-08Bibliographically approved
Strasevicius, D., Jonsson, M., Nyholm, N. E. & Malmqvist, B. (2013). Reduced breeding success of Pied Flycatchers Ficedula hypoleuca along regulated rivers. Ibis, 155(2), 348-356
Open this publication in new window or tab >>Reduced breeding success of Pied Flycatchers Ficedula hypoleuca along regulated rivers
2013 (English)In: Ibis, ISSN 0019-1019, E-ISSN 1474-919X, Vol. 155, no 2, p. 348-356Article in journal (Refereed) Published
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.

National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-68255 (URN)10.1111/ibi.12024 (DOI)000316327000011 ()
Available from: 2013-04-18 Created: 2013-04-15 Last updated: 2018-06-08Bibliographically approved
Woodward, G., Gessner, M. O., Giller, P. S., Gulis, V., Hladyz, S., Lecerf, A., . . . Chauvet, E. (2012). Continental-Scale Effects of Nutrient Pollution on Stream Ecosystem Functioning. Science, 336(6087), 1438-1440
Open this publication in new window or tab >>Continental-Scale Effects of Nutrient Pollution on Stream Ecosystem Functioning
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2012 (English)In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 336, no 6087, p. 1438-1440Article in journal (Refereed) Published
Abstract [en]

Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process-leaf-litter breakdown-in 100 streams across a greater than 1000-fold nutrient gradient. Dramatically slowed breakdown at both extremes of the gradient indicated strong nutrient limitation in unaffected systems, potential for strong stimulation in moderately altered systems, and inhibition in highly polluted streams. This large-scale response pattern emphasizes the need to complement established structural approaches (such as water chemistry, hydrogeomorphology, and biological diversity metrics) with functional measures (such as litter-breakdown rate, whole-system metabolism, and nutrient spiraling) for assessing ecosystem health.

National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-56972 (URN)10.1126/science.1219534 (DOI)000305211700045 ()
Available from: 2012-07-04 Created: 2012-07-02 Last updated: 2018-06-08Bibliographically approved
Jonsson, M., Strasevicius, D. & Malmqvist, B. (2012). Influences of river regulation and environmental variables on upland bird assemblages in northern Sweden. Ecological research, 27(5), 945-954
Open this publication in new window or tab >>Influences of river regulation and environmental variables on upland bird assemblages in northern Sweden
2012 (English)In: Ecological research, ISSN 0912-3814, E-ISSN 1440-1703, Vol. 27, no 5, p. 945-954Article in journal (Refereed) Published
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.

Keywords
Aquatic insect, Bird assemblage, Boreal region, Land-water interaction, River regulation
National Category
Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-61198 (URN)10.1007/s11284-012-0974-0 (DOI)000308951600014 ()
Available from: 2012-11-08 Created: 2012-11-07 Last updated: 2018-06-08Bibliographically approved
Hladyz, S., Åbjörnsson, K., Chauvet, E., Dobson, M., Elosegi, A., Ferreira, V., . . . Woodward, G. (2011). Stream ecosystem functioning in an agricultural landscape: the importance of terrestrial-aquatic linkages. In: Guy Woodward (Ed.), Ecosystems in a human-modified landscape: a european perspective (pp. 211-276). Amsterdam: Academic Press, 44
Open this publication in new window or tab >>Stream ecosystem functioning in an agricultural landscape: the importance of terrestrial-aquatic linkages
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2011 (English)In: Ecosystems in a human-modified landscape: a european perspective / [ed] Guy Woodward, Amsterdam: Academic Press, 2011, Vol. 44, p. 211-276Chapter in book (Refereed)
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.

Place, publisher, year, edition, pages
Amsterdam: Academic Press, 2011
Series
Advances in Ecological Research, ISSN 0065-2504 ; 44
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-47413 (URN)10.1016/B978-0-12-374794-5.00004-3 (DOI)000293800600005 ()978-0-12-374794-5 (ISBN)
Available from: 2011-09-20 Created: 2011-09-20 Last updated: 2018-06-08Bibliographically approved
Perkins, D. M., Mckie, B. G., Malmqvist, B., Gilmour, S. G., Reiss, J. & Woodward, G. (2010). Environmental Warming and Biodiversity-Ecosystem Functioning in Freshwater Microcosms: Partitioning the Effects of Species Identity, Richness and Metabolism. In: Guy Woodward, School of Biological and Chemical Sciences, Queen Mary University of London, London (Ed.), Integrative Ecology: From Molecules to Ecosystems (pp. 177-209). Academic Press
Open this publication in new window or tab >>Environmental Warming and Biodiversity-Ecosystem Functioning in Freshwater Microcosms: Partitioning the Effects of Species Identity, Richness and Metabolism
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2010 (English)In: Integrative Ecology: From Molecules to Ecosystems / [ed] Guy Woodward, School of Biological and Chemical Sciences, Queen Mary University of London, London, Academic Press, 2010, p. 177-209Chapter in book (Refereed)
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.

Place, publisher, year, edition, pages
Academic Press, 2010
Series
Advances in Ecological Research, ISSN 0065-2504 ; 43
Keywords
Allometric scaling, Body size, Climate change, Decomposition, Global warming, Metabolic capacity, Species identity, Thermal optima
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-75750 (URN)10.1016/B978-0-12-385005-8.00005-8 (DOI)000286800200006 ()978-0-12-385005-8 (ISBN)
Available from: 2013-07-03 Created: 2013-07-03 Last updated: 2018-06-08Bibliographically approved
McKie, B. & Malmqvist, B. (2009). Assessing ecosystem functioning in streams affected by forest management: increased leaf decomposition occurs without changes to the composition of benthic assemblages. Freshwater Biology, 54(10), 2086-2100
Open this publication in new window or tab >>Assessing ecosystem functioning in streams affected by forest management: increased leaf decomposition occurs without changes to the composition of benthic assemblages
2009 (English)In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 54, no 10, p. 2086-2100Article in journal (Refereed) Published
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.

Identifiers
urn:nbn:se:umu:diva-25974 (URN)10.1111/j.1365-2427.2008.02150.x (DOI)
Available from: 2009-09-16 Created: 2009-09-16 Last updated: 2018-06-08Bibliographically approved
Lepori, F. & Malmqvist, B. (2009). Deterministic control on community assembly peaks at intermediate levels of disturbance. Oikos, 118(3), 471-479
Open this publication in new window or tab >>Deterministic control on community assembly peaks at intermediate levels of disturbance
2009 (English)In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 118, no 3, p. 471-479Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2009
Keywords
species traits, stream, biodiversity, diversity, patterns, forest, invertebrates, heterogeneity, equilibrium, environment
National Category
Environmental Sciences Ecology
Identifiers
urn:nbn:se:umu:diva-116022 (URN)10.1111/j.1600-0706.2008.16989.x (DOI)000263967000018 ()
Available from: 2016-02-22 Created: 2016-02-08 Last updated: 2018-06-07Bibliographically approved
Göthe, E., Lepori, F. & Malmqvist, B. (2009). Forestry affects food webs in northern Swedish coastal streams. Fundamental and Applied Limnology, 175(4), 281-294
Open this publication in new window or tab >>Forestry affects food webs in northern Swedish coastal streams
2009 (English)In: Fundamental and Applied Limnology, ISSN 1863-9135, Vol. 175, no 4, p. 281-294Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Stuttgart: E. Schweizerbart'sche Verlagsbuchhandlung, 2009
Keywords
stable isotope analysis, clear-cutting, trophic shifts, heterotrophic-autotrophic energy sources, riparian logging
National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:umu:diva-115948 (URN)10.1127/1863-9135/2009/0175-0281 (DOI)000274359100002 ()
Available from: 2016-02-29 Created: 2016-02-08 Last updated: 2018-06-07Bibliographically approved
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