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Jansson, Roland
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Publications (10 of 61) Show all publications
Sarneel, J. M., Hefting, M. M., Kowalchuk, G. A., Nilsson, C., Van der Velden, M., Visser, E. J. W., . . . Jansson, R. (2019). Alternative transient states and slow plant community responses after changed flooding regimes. Global Change Biology, 25(4), 1358-1367
Open this publication in new window or tab >>Alternative transient states and slow plant community responses after changed flooding regimes
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2019 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 25, no 4, p. 1358-1367Article in journal (Refereed) Published
Abstract [en]

Climate change will have large consequences for flooding frequencies in freshwater systems. In interaction with anthropogenic activities (flow regulation, channel restoration and catchment land-use) this will both increase flooding and drought across the world. Like in many other ecosystems facing changed environmental conditions, it remains difficult to predict the rate and trajectory of vegetation responses to changed conditions. Given that critical ecosystem services (e.g. bank stabilization, carbon subsidies to aquatic communities or water purification) depend on riparian vegetation composition, it is important to understand how and how fast riparian vegetation responds to changing flooding regimes. We studied vegetation changes over 19 growing seasons in turfs that were transplanted in a full-factorial design between three riparian elevations with different flooding frequencies. We found that (a) some transplanted communities may have developed into an alternative stable state and were still different from the target community, and (b) pathways of vegetation change were highly directional but alternative trajectories did occur, (c) changes were rather linear but faster when flooding frequencies increased than when they decreased, and (d) we observed fastest changes in turfs when proxies for mortality and colonization were highest. These results provide rare examples of alternative transient trajectories and stable states under field conditions, which is an important step towards understanding their drivers and their frequency in a changing world.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
alternative stable states, drought events, flood regime change, hydrological alterations, hysteresis, riparian vegetation, river restoration, species traits
National Category
Ecology Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-157948 (URN)10.1111/gcb.14569 (DOI)000461817500013 ()30638293 (PubMedID)
Available from: 2019-04-18 Created: 2019-04-18 Last updated: 2019-04-18Bibliographically approved
Karlsson Tiselius, A., Lundbäck, S., Lönnell, N., Jansson, R. & Dynesius, M. (2019). Bryophyte community assembly on young land uplift islands: dispersal and habitat filtering assessed using species traits. Journal of Biogeography, 46(10), 2188-2202
Open this publication in new window or tab >>Bryophyte community assembly on young land uplift islands: dispersal and habitat filtering assessed using species traits
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2019 (English)In: Journal of Biogeography, ISSN 0305-0270, E-ISSN 1365-2699, Vol. 46, no 10, p. 2188-2202Article in journal (Refereed) Published
Abstract [en]

Aim: To assess habitat filtering and dispersal limitation in spore plant community assembly using bryophytes on recently emerged land uplift islands as study system. Location Gulf of Bothnia, northern Europe. Taxa Bryophytes, including the spore plant phyla Bryophyta (mosses) and Marchantiophyta (liverworts).

Methods: The species compositions of 20 coastal land uplift islands differing in age, area, connectivity and habitat composition were recorded in the field. In addition, we compiled a list of the regional species pool (446 species) and gathered data on species traits related to habitat affiliations (substrate, light, moisture, and pH) and dispersal capacity (regional abundance, spore size, sporophyte frequency, sexual system, vegetative propagules). For the 420 species with available trait data, we used multivariate generalized linear models to compare trait effects on species occurrence probabilities on the islands.

Results: Occurrence probabilities depended strongly on habitat affiliations. In addition, occurrence probabilities were lower for predominantly asexual species than for sexual species and for regionally rare than for regionally abundant species. Having specialized asexual propagules increased occurrence probabilities, but compensated only partly for the reductions in asexual species. No effect of the size of sexually produced spores was detected. Comparison of trait effects across island size and connectivity gradients revealed (a) reduced habitat filtering on larger islands and (b) decreasing negative effects of being predominantly asexual with increasing island connectivity.

Conclusions: Both habitat filtering and dispersal capacities affect the community assembly of spore plants on land uplift islands. Asexual mosses and liverworts show landscape scale (<= 10 km) dispersal limitation. The weak or absent relationships between island connectivity and the effects of dispersal traits suggest that colonization is regulated mainly by habitat availability and the abundance of each species in a "regional spore rain" from which colonists are recruited.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
colonization, community assembly, dispersal limitation, habitat availability, liverworts, mosses; reduced rank vector generalized linear models, sporophytes, trait based community ecology, vegetative propagules
National Category
Ecology
Research subject
Ecological Botany; Conservation Biology
Identifiers
urn:nbn:se:umu:diva-121236 (URN)10.1111/jbi.13652 (DOI)000481048700001 ()2-s2.0-85070330223 (Scopus ID)
Funder
Swedish Research Council Formas, 215-2010-998
Note

Originally published in thesis in manuscript form.

Available from: 2016-06-01 Created: 2016-05-30 Last updated: 2019-12-19Bibliographically approved
Jansson, R., Ström, L. & Nilsson, C. (2019). Smaller future floods imply less habitat for riparian plants along a boreal river. Ecological Applications, 29(8), Article ID e01977.
Open this publication in new window or tab >>Smaller future floods imply less habitat for riparian plants along a boreal river
2019 (English)In: Ecological Applications, ISSN 1051-0761, E-ISSN 1939-5582, Vol. 29, no 8, article id e01977Article in journal (Refereed) Published
Abstract [en]

Climate-change projections suggest large changes in riverine flow regime, which will likely alter riparian communities. In northern Europe, forecasts propose lower annual spring flood peaks and higher winter flows, resulting in narrower riparian zones. To estimate the impact of climate change on habitat extent of riparian plants, we developed a framework estimating the sensitivity and exposure of individual species to streamflow change, and surveyed five reaches along the free-flowing Vindel River in northern Sweden. We modeled the hydrologic niche of riparian plant species based on the probability of occurrence along gradients of flood frequency and duration and used predicted future water-level fluctuations (based on climate models and IPCC emission scenarios) to calculate changes in flow-related habitat availability of individual species. Despite projected increases in runoff, we predict most species to decrease in riparian elevational extent by on average 12-29% until the end of the century, depending on scenario. Species growing in the upper, spring-flood-controlled part of the riparian zone will likely lose most habitat, with the largest reductions in species with narrow ranges of inundation duration tolerance (decreases of up to 54%). In contrast, the elevational extent of most amphibious species is predicted to increase, but conditions creating isoetid vegetation will become rarer or disappear: isoetid vegetation is presently found in areas where ice formed in the fall settles on the riverbank during the winter as water levels subside. Higher winter flows will make these conditions rare. We argue that our framework is useful to project the effects of hydrologic change caused by climate change as well as other stressors such as flow regulation also in other regions. With few rivers remaining unaffected by dams and other human stressors, these results call for monitoring to detect species declines. Management to alleviate species losses might include mitigation of habitat degradation from land-use activities, more environmentally friendly flow schemes, and more intensive management options such as mowing riparian meadows no longer regularly maintained by recurrent floods.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
climate change, flooding, inundation, niche width, riverbanks, river, water table
National Category
Ecology Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-162858 (URN)10.1002/eap.1977 (DOI)000481122800001 ()31323161 (PubMedID)2-s2.0-85070303264 (Scopus ID)
Available from: 2019-09-06 Created: 2019-09-06 Last updated: 2020-01-09Bibliographically approved
Pontarp, M., Bunnefeld, L., Cabral, J. S., Etienne, R. S., Fritz, S. A., Gillespie, R., . . . Hurlbert, A. H. (2019). The Latitudinal Diversity Gradient: Novel Understanding through Mechanistic Eco-evolutionary. Trends in Ecology & Evolution, 34(3), 211-223
Open this publication in new window or tab >>The Latitudinal Diversity Gradient: Novel Understanding through Mechanistic Eco-evolutionary
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2019 (English)In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 34, no 3, p. 211-223Article, review/survey (Refereed) Published
Abstract [en]

The latitudinal diversity gradient (LDG) is one of the most widely studied patterns in ecology, yet no consensus has been reached about its underlying causes. We argue that the reasons for this are the verbal nature of existing hypotheses, the failure to mechanistically link interacting ecological and evolutionary processes to the LDG, and the fact that empirical patterns are often consistent with multiple explanations. To address this issue, we synthesize current LDG hypotheses, uncovering their eco-evolutionary mechanisms, hidden assumptions, and commonalities. Furthermore, we propose mechanistic eco-evolutionary modeling and an inferential approach that makes use of geographic, phylogenetic, and trait-based patterns to assess the relative importance of different processes for generating the LDG.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
diversity patterns, mechanistic modeling, ecology, evolution, biogeography, macroecology
National Category
Evolutionary Biology Environmental Sciences Genetics
Identifiers
urn:nbn:se:umu:diva-157579 (URN)10.1016/j.tree.2018.11.009 (DOI)000459899000011 ()30591209 (PubMedID)
Available from: 2019-04-01 Created: 2019-04-01 Last updated: 2019-04-01Bibliographically approved
Nogues-Bravo, D., Rodriguez-Sanchez, F., Orsini, L., de Boer, E., Jansson, R., Morlon, H., . . . Jackson, S. T. (2018). Cracking the code of biodiversity responses to past climate change. Trends in Ecology & Evolution, 33(10), 765-776
Open this publication in new window or tab >>Cracking the code of biodiversity responses to past climate change
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2018 (English)In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 33, no 10, p. 765-776Article, review/survey (Refereed) Published
Abstract [en]

How individual species and entire ecosystems will respond to future climate change are among the most pressing questions facing ecologists. Past biodiversity dynamics recorded in the paleoecological archives show a broad array of responses, yet significant knowledge gaps remain. In particular, the relative roles of evolutionary adaptation, phenotypic plasticity, and dispersal in promoting survival during times of climate change have yet to be clarified. Investigating the paleo-archives offers great opportunities to understand biodiversity responses to future climate change. In this review we discuss the mechanisms by which biodiversity responds to environmental change, and identify gaps of knowledge on the role of range shifts and tolerance. We also outline approaches at the intersection of paleoecology, genomics, experiments, and predictive models that will elucidate the processes by which species have survived past climatic changes and enhance predictions of future changes in biological diversity.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Climate Research
Identifiers
urn:nbn:se:umu:diva-153711 (URN)10.1016/j.tree.2018.07.005 (DOI)000447963700006 ()30173951 (PubMedID)
Funder
EU, European Research Council, ERC 616419-PANDA
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2018-11-27Bibliographically approved
Frainer, A., Polvi, L. E., Jansson, R. & McKie, B. G. (2018). Enhanced ecosystem functioning following stream restoration: The roles of habitat heterogeneity and invertebrate species traits. Journal of Applied Ecology, 55(1), 377-385
Open this publication in new window or tab >>Enhanced ecosystem functioning following stream restoration: The roles of habitat heterogeneity and invertebrate species traits
2018 (English)In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 55, no 1, p. 377-385Article in journal (Refereed) Published
Abstract [en]

1. Habitat restoration is increasingly undertaken in degraded streams and rivers to help improve biodiversity and ecosystem functioning. Follow-up assessments focused on outcomes for biodiversity have often found scant evidence for recovery, raising concerns about the efficacy of habitat restoration for improving ecological integrity. However, responses of other ecological variables, such as ecosystem process rates and the functional trait composition of biological assemblages, have been little evaluated.

2. We assessed how the restoration of habitat heterogeneity affected multiple functional parameters in 20 boreal stream reaches encompassing both more and less extensively restored sites, as well as channelised and natural reference sites. We further assessed relationships between our functional parameters and a fluvial geomorphic measure of habitat heterogeneity.

3. Leaf decomposition was positively related to habitat heterogeneity. This was associated with shifts in the functional composition of detritivore assemblages, with the most obligate litter consumers more prominent in reaches showing higher habitat heterogeneity. The deposition of fine particulate organic matter was consistently higher in restored than channelised sites, and was positively related to the heterogeneity gradient. Algal biomass accrual per unit area did not vary either with restoration or the heterogeneity gradient.

4. Synthesis and applications. Our findings demonstrate that restoration of river habitat heterogeneity can enhance retention and decomposition of organic matter, key ecosystem properties underpinning ecosystem functioning and service delivery. Significantly, enhanced litter decomposition was linked with a change in the functional composition rather than diversity of detritivore assemblages. Future evaluation of the success of habitat restorations should incorporate quantification of ecosystem processes and the functional traits of biota, in addition to measures of fluvial geomorphology and more traditional biotic metrics, to facilitate a more comprehensive and mechanistic assessment of ecological responses.

Place, publisher, year, edition, pages
Wiley-Blackwell Publishing Inc., 2018
Keywords
algal production, biodiversity, community-weighted mean trait values, ecosystem function, FPOM retention and deposition, functional diversity, restoration assessments, river habitat, streams
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-143634 (URN)10.1111/1365-2664.12932 (DOI)000417764600037 ()
Available from: 2018-01-29 Created: 2018-01-29 Last updated: 2018-06-09Bibliographically approved
Bejarano, M. D., Jansson, R. & Nilsson, C. (2018). The effects of hydropeaking on riverine plants: a review. Biological Reviews, 93(1), 658-673
Open this publication in new window or tab >>The effects of hydropeaking on riverine plants: a review
2018 (English)In: Biological Reviews, ISSN 1464-7931, E-ISSN 1469-185X, Vol. 93, no 1, p. 658-673Article, review/survey (Refereed) Published
Abstract [en]

Hydropeaking refers to frequent, rapid and short-term fluctuations in water flow and water levels downstream and upstream of hydropower stations. Such fluctuations are becoming increasingly common worldwide and are known to have far-reaching effects on riverine vegetation. Novel hydrology caused by hydropeaking has no natural correspondence in freshwater systems, and hence few species have adaptations to all its aspects. Here, we review the literature on hydropeaking effects on riverine plants and define the state of the information on this human alteration of riverine ecosystems. We focus on riparian plants, but also draw on information from aquatic plant species, which exhibit a wide variety of adaptations to inundation and associated processes. Riparian plants face both physiological and physical constraints because of the shifts between submergence and drainage, and erosion of substrates. At the population level, hydropeaking may favour dispersal within, but not between, reservoirs, but may hamper germination, establishment, growth and reproduction. At the community level, strong filtering towards easily dispersed, flexible, flood-tolerant and amphibious plants is expected, although few species share these traits. Hence, most riparian plant species are expected to disappear or be pushed towards the upper boundaries of the regulated river margin. Future research should examine more closely global variation in hydropeaking effects, including other taxonomic groups of species and the diversity of hydropeaking regimes. There is also a need for studies focusing on identifying the boundaries within which hydropeaking could operate without impairing plant life.

Place, publisher, year, edition, pages
WILEY, 2018
Keywords
catchment management, environmental flows, hydropeaking, hydropower, plant communities, plant nctional traits, riparian vegetation, riverine vegetation
National Category
Biological Sciences
Identifiers
urn:nbn:se:umu:diva-144338 (URN)10.1111/brv.12362 (DOI)000419965700033 ()28815925 (PubMedID)
Available from: 2018-02-08 Created: 2018-02-08 Last updated: 2018-08-20Bibliographically approved
Rodriguez-Castaneda, G., Hof, A. R. & Jansson, R. (2017). How bird clades diversify in response to climatic and geographic factors. Ecology Letters, 20(9), 1129-1139
Open this publication in new window or tab >>How bird clades diversify in response to climatic and geographic factors
2017 (English)In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 20, no 9, p. 1129-1139Article in journal (Refereed) Published
Abstract [en]

While the environmental correlates of global patterns in standing species richness are well understood, it is poorly known which environmental factors promote diversification (speciation minus extinction) in clades. We tested several hypotheses for how geographic and climatic variables should affect diversification using a large dataset of bird sister genera endemic to the New World. We found support for the area, evolutionary speed, environmental predictability and climatic stability hypotheses, but productivity and topographic complexity were rejected as explanations. Genera that had accumulated more species tend to occupy wider niche space, manifested both as occurrence over wider areas and in more habitats. Genera with geographic ranges that have remained more stable in response to glacial-interglacial changes in climate were also more species rich. Since many relevant explanatory variables vary latitudinally, it is crucial to control for latitude when testing alternative mechanistic explanations for geographic variation in diversification among clades.

Place, publisher, year, edition, pages
WILEY, 2017
Keywords
Climate stability, ecological niche modelling, energy availability, geographic area, habitat diversity, phylogenetic independent contrasts, sister group comparisons, species richness, temperate, tropical
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-138578 (URN)10.1111/ele.12809 (DOI)000407391900004 ()
Available from: 2017-09-29 Created: 2017-09-29 Last updated: 2018-06-09Bibliographically approved
Kuglerova, L., Botkova, K. & Jansson, R. (2017). Responses of riparian plants to habitat changes following restoration of channelized streams. Ecohydrology, 10(1), Article ID UNSP e1798.
Open this publication in new window or tab >>Responses of riparian plants to habitat changes following restoration of channelized streams
2017 (English)In: Ecohydrology, ISSN 1936-0584, E-ISSN 1936-0592, Vol. 10, no 1, article id UNSP e1798Article in journal (Refereed) Published
Abstract [en]

The ecological effects of stream restoration were evaluated by comparing riparian vegetation, flooding, and habitat properties between channelized and two types of restored streams in northern Sweden. Channelized streams were straightened and cleared of in-stream boulders and wood >50 years ago to facilitate timber floating. Basic restoration (performed 8-10 years ago) returned cleared material back to the channels, and enhanced restoration (3 years ago) added large structural elements (boulders and downed trees) to previously basic-restored streams. Riparian inundation duration increased only after enhanced restoration. Similarly, enhanced-restored reaches had the highest amount of substrate available for plant establishment compared to channelized and basic-restored streams. In contrast, soil biochemical properties (pH and C:N ratio) did not improve following either restoration effort. Riparian plant cover was higher at both restored types than channelized reaches. Plant species richness was higher at plot-scale level (0.25 m(2)) at both restored types in the most species-rich elevation levels compared to channelized reaches, whereas at the reach-scale (>700 m(2) of riparian area), species richness did not differ among stream types. Similarly, species composition segregated between channelized and restored reaches only at the plot scale. We found no significant differences in riparian vegetation between the two restored types. The lack of positive responses of vegetation to enhanced restoration and to variables that changed immediately after restoration (inundation, habitat area) implies that responses were either slower than expected or the changes in hydrology and substrate availability were not as important for riparian flora as believed.

Place, publisher, year, edition, pages
WILEY-BLACKWELL, 2017
Keywords
channelization, flooding, habitat quality and quantity, riparian vegetation, stream restoration, vascular plants
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-132835 (URN)10.1002/eco.1798 (DOI)000393870100024 ()
Available from: 2017-04-05 Created: 2017-04-05 Last updated: 2018-06-09Bibliographically approved
Blume-Werry, G., Jansson, R. & Milbau, A. (2017). Root phenology unresponsive to earlier snowmelt despite advanced above-ground phenology in two subarctic plant communities. Functional Ecology, 31(7), 1493-1502
Open this publication in new window or tab >>Root phenology unresponsive to earlier snowmelt despite advanced above-ground phenology in two subarctic plant communities
2017 (English)In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 31, no 7, p. 1493-1502Article in journal (Refereed) Published
Abstract [en]

1. Earlier snowmelt at high latitudes advances above-ground plant phenology, thereby affecting water, nutrient and carbon cycles. Despite the key role of fine roots in these ecosystem processes, phenological responses to earlier snowmelt have never been assessed below-ground. 2. We experimentally advanced snowmelt in two contrasting plant community types (heath and meadow) in northern Sweden and measured above- and below-ground phenology (leaf-out, flowering and fine root growth). We expected earlier snowmelt to advance both above- and below-ground phenology, and shrub-dominated heath to be more responsive than meadow. 3. Snow melted on average 9 days earlier in the manipulated plots than in controls, and soil temperatures were on average 0.9 degrees C higher during the snowmelt period of 3 weeks. This resulted in small advances in above-ground phenology, but contrary to our expectations, root phenology was unresponsive, with root growth generally starting before leaf-out. These responses to the snowmelt treatment were similar in both plant community types, despite strong differences in dominating plant functional types and root properties, such as root length and turnover. 4. The lack of a response in root phenology, despite warmer soil temperatures and above-ground phenological advances, adds evidence that above-ground plant responses might not be directly translated to below-ground plant responses, and that our understanding of factors driving below-ground phenology is still limited, although of major importance for water, nutrient and carbon cycling.

Place, publisher, year, edition, pages
John Wiley & Sons, 2017
Keywords
alpine, arctic, climate change, fine roots, phenology, root growth, root production, snowmelt
National Category
Botany Soil Science
Identifiers
urn:nbn:se:umu:diva-138548 (URN)10.1111/1365-2435.12853 (DOI)000404860200014 ()
Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2018-06-09Bibliographically approved
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