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Rydin, Håkan
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Publications (10 of 127) Show all publications
Bengtsson, F., Rydin, H. & Hajek, T. (2018). Biochemical determinants of litter quality in 15 species of Sphagnum. Plant and Soil, 425(1-2), 161-176
Open this publication in new window or tab >>Biochemical determinants of litter quality in 15 species of Sphagnum
2018 (English)In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 425, no 1-2, p. 161-176Article in journal (Refereed) Published
Abstract [en]

Background and aims Sphagnum mosses are ecosystem engineers that create and maintain boreal peatlands. With unique biochemistry, waterlogging and acidifying capacities, they build up meters-thick layers of peat, reducing competition and impeding decomposition. We quantify within-genus differences in biochemical composition to make inferences about decay rates, related to hummock-hollow and fen-bog gradients and to phylogeny. Methods We sampled litter from 15 Sphagnum species, abundant over the whole northern hemisphere. We used regression and Principal Components Analysis (PCA) to evaluate general relationships between litter quality parameters and decay rates measured under laboratory and field conditions. Results Both concentrations of the polysaccharide sphagnan and the soluble phenolics were positively correlated with intrinsic decay resistance, however, so were the previously understudied lignin-like phenolics. More resistant litter had more of all the important metabolites; consequently, PC1 scores were related to lab mass loss (R-2 = 0.57). There was no such relationship with field mass loss, which is also affected by the environment. PCA also revealed that metabolites clearly group Sphagnum sections (subgenera). Conclusions We suggest that the commonly stated growth-decomposition trade-off is largely due to litter quality. We show a strong phylogenetic control on Sphagnum metabolites, but their effects on decay are affected by nutrient availability in the habitat.

Keywords
Peatland, Decay resistance, Sphagnan, Phenolics, Lignin, Hummock-hollow
National Category
Botany
Identifiers
urn:nbn:se:uu:diva-354249 (URN)10.1007/s11104-018-3579-8 (DOI)000430992300011 ()
Funder
Swedish Research CouncilThe Royal Swedish Academy of Sciences
Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-06-29Bibliographically approved
Emsens, W.-J., Aggenbach, C. J. S., Rydin, H., Smolders, A. J. P. & van Diggelen, R. (2018). Competition for light as a bottleneck for endangered fen species: An introduction experiment. Biological Conservation, 220, 76-83
Open this publication in new window or tab >>Competition for light as a bottleneck for endangered fen species: An introduction experiment
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2018 (English)In: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 220, p. 76-83Article in journal (Refereed) Published
Abstract [en]

Many endangered plant species remain absent in rewetted, previously drained fens. We performed a 3-year introduction experiment with endangered fen species (9 Carex- and 6 bryophyte species) in 4 hydrologically restored fens to investigate which factors hamper establishment and survival. Carex species were introduced as adults and seedlings, mosses as gametophytes. Introductions were done on (initially) bare soil, which allowed us to exclude excessive competition for light during the first year. First year survival of the transplants was high in all fens (mean survival = 96%), indicating that there were no direct abiotic constraints on establishment. However, survival analysis revealed that a decrease in relative light intensity (RLI) at the soil surface during consecutive years (indicating an increase in biotic competition for light) drove high mortality rates in most species. As a result, overall final survival was lowest in the two most productive (low light) fens (mean survival = 38%), while most transplants persisted in the two less productive (high light) fens (mean survival = 79%). Taller and faster-growing Carex species were able to outgrow light limitation near the soil surface, and thus had a higher overall survivability than smaller and slower-growing species. Light limitation also drove the loss of 5 out of 6 bryophyte species. We conclude that both dispersal limitation and asymmetric competition for light may explain the lack and loss of small and endangered plant species in rewetted fens. A minimum empirical threshold of c. 30% relative light intensity near the soil surface is required for successful introduction.

Keywords
Biodiversity, Competition, Dispersal limitation, Fen restoration, Light availability
National Category
Botany Ecology
Identifiers
urn:nbn:se:uu:diva-354252 (URN)10.1016/j.biocon.2018.02.002 (DOI)000429765000009 ()
Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-06-29Bibliographically approved
Lou, Y., Gao, C., Pan, Y., Xue, Z., Liu, Y., Tang, Z., . . . Rydin, H. (2018). Niche modelling of marsh plants based on occurrence and abundance data. Science of the Total Environment, 616-617, 198-207
Open this publication in new window or tab >>Niche modelling of marsh plants based on occurrence and abundance data
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2018 (English)In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 616-617, p. 198-207Article in journal (Refereed) Published
Abstract [en]

The information of species' response (optimum or critical limits along environmental gradients) is a key to understanding ecological questions and to design management plans. A large number of plots (762) from 70 transects of 13 wetland sites in Northeast China were sampled along flooding gradient from marsh to wet meadow. Species response (abundance and occurrence) to flooding were modelled with Generalized Additive Models for 21 dominant plant species. We found that 20 of 21 species showed a significant response to flooding for the occurrence and abundance models, and four types of response were found: monotonically increasing, monotonically decreasing, skewed unimodal and symmetric unimodal. The species with monotonically increasing response have the deepest flooding optimum and widest niche width, followed by those with unimodal curve, and the monotonically decreasing ones have the smallest values. The optima and niche width (whether based on occurrence or abundance models) both significantly correlated with the frequency, but not with mean abundance. Abundance models outperformed occurrence models based on goodness of fit. The abundance models predicted a rather sharp shift from dominance of helophytes (Carex pseudo-curaica and C. lasiocarpa) to wet meadow species (Calamagrostis angustifolia and Carex appendiculata) if water levels drop from about 10 cm above soil surface to below the surface. The defined optima and niche width based on the abundance models can be applied to better instruct restoration management. Given the time required to collect abundance data, an efficient strategy could be to monitor occurrence in many plots and abundance in a subset of these.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2018
Keywords
Species response curve, Optimum, Niche width, Distribution, Generalized Additive Models (GAM), Herbaceous marsh
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-346655 (URN)10.1016/j.scitotenv.2017.10.300 (DOI)000424121800020 ()29121575 (PubMedID)
Available from: 2018-03-20 Created: 2018-03-20 Last updated: 2018-03-20Bibliographically approved
Weston, D. J., Turetsky, M. R., Johnson, M. G., Granath, G., Lindo, Z., Belyea, L. R., . . . Shaw, A. J. (2018). The Sphagnome Project: enabling ecological and evolutionary insights through a genus-level sequencing project. New Phytologist, 217(1), 16-25
Open this publication in new window or tab >>The Sphagnome Project: enabling ecological and evolutionary insights through a genus-level sequencing project
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2018 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 217, no 1, p. 16-25Article in journal, Editorial material (Other academic) Published
Abstract [en]

Considerable progress has been made in ecological and evolutionary genetics with studies demonstrating how genes underlying plant and microbial traits can influence adaptation and even 'extend' to influence community structure and ecosystem level processes. Progress in this area is limited to model systems with deep genetic and genomic resources that often have negligible ecological impact or interest. Thus, important linkages between genetic adaptations and their consequences at organismal and ecological scales are often lacking. Here we introduce the Sphagnome Project, which incorporates genomics into a long-running history of Sphagnum research that has documented unparalleled contributions to peatland ecology, carbon sequestration, biogeochemistry, microbiome research, niche construction, and ecosystem engineering. The Sphagnome Project encompasses a genus-level sequencing effort that represents a new type of model system driven not only by genetic tractability, but by ecologically relevant questions and hypotheses.

Keywords
ecological genomics, ecosystem engineering, evolutionary genetics, genome sequencing, niche construction, peatlands, Sphagnome, Sphagnum
National Category
Genetics and Breeding in Agricultural Sciences Ecology
Identifiers
urn:nbn:se:uu:diva-351606 (URN)10.1111/nph.14860 (DOI)000426309500004 ()29076547 (PubMedID)
Available from: 2018-05-29 Created: 2018-05-29 Last updated: 2018-05-29Bibliographically approved
Hytteborn, H., Svensson, B. M., Kempe, K., Press, A. & Rydin, H. (2017). Century-long tree population dynamics in a deciduous forest stand in central Sweden. Journal of Vegetation Science, 28(5), 1057-1069
Open this publication in new window or tab >>Century-long tree population dynamics in a deciduous forest stand in central Sweden
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2017 (English)In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 28, no 5, p. 1057-1069Article in journal (Refereed) Published
Abstract [en]

Question: We quantify tree dynamics over a century of free development in a small broadleaved forest dominated by Fraxinus excelsior and Ulmus glabra. What are the internal and external factors driving the changes, and how predictable are they? What were the time scale and effects of the spread of Dutch elm disease (DED)? Location: Vårdsätra, eastern central Sweden.

Methods: The survival, growth and recruitment of all trees (≥ 12 cm in girth) were monitored in 1912, 1967, 1988 and 2013 (more often for a part of the forest). Woody species in the field and shrub layers were surveyed in permanent plots in 1976 and 2012. We used transition matrix models to project changes in population sizes and species composition within the century and for 2050.

Results: The results indicate that the forest was in a successional development during the first period. The species composition had stabilised by 1967, except for an expansion of Acer platanoides and the drastic effect of DED that struck the forest around 2000. It took only a decade to kill virtually all large elms in the forest, leading to strong decrease in stem density and basal area. The evidence for effects of DED is still weak, but there has been an increase in saplings, notably of Fraxinus, Prunus padus, Ulmus, and of shoots of Corylus avellana. Several species that are abundant in the vicinity and as seeds fail to establish (Picea abies, Betula spp., Quercus robur, Populus tremula). Projections for 2050 based on the third period (1988-2013) are probably unrealistic since also Fraxinus may disappear because of the recent arrival of the ash dieback.

Conclusions: Slow dynamics in forests that could follow from climate change will locally probably be overruled by unforeseen catastrophes, such as invasions by forest pathogens. These initiate changes with long lag phases difficult to quantify. Still, a dense deciduous forest can resist invasion of colonist species and of regionally dominant conifers; the reason being unfavourable conditions for establishment rather than dispersal limitation

National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-325261 (URN)10.1111/jvs.12556 (DOI)000408818000017 ()
Funder
Swedish Research Council
Available from: 2017-06-22 Created: 2017-06-22 Last updated: 2017-12-11Bibliographically approved
Hedwall, P.-O., Brunet, J. & Rydin, H. (2017). Peatland plant communities under global change: negative feedback loops counteract shifts in species composition. Ecology, 98(1), 150-161
Open this publication in new window or tab >>Peatland plant communities under global change: negative feedback loops counteract shifts in species composition
2017 (English)In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 98, no 1, p. 150-161Article in journal (Refereed) Published
Abstract [en]

Mires (bogs and fens) are nutrient-limited peatland ecosystems, the vegetation of which is especially sensitive to nitrogen deposition and climate change. The role of mires in the global carbon cycle, and the delivery of different ecosystem services can be considerably altered by changes in the vegetation, which has a strong impact on peat-formation and hydrology. Mire ecosystems are commonly open with limited canopy cover but both nitrogen deposition and increased temperatures may increase the woody vegetation component. It has been predicted that such an increase in tree cover and the associated effects on light and water regimes would cause a positive feed-back loop with respect to the ground vegetation. None of these effects, however, have so far been confirmed in large-scale spatiotemporal studies. Here we analyzed data pertaining to mire vegetation from the Swedish National Forest Inventory collected from permanent sample plots over a period of 20 yr along a latitudinal gradient covering 14 degrees. We hypothesized that the changes would be larger in the southern parts as a result of higher nitrogen deposition and warmer climate. Our results showed an increase in woody vegetation with increases in most ericaceous dwarf-shrubs and in the basal area of trees. These changes were, in contrast to our expectations, evenly distributed over most of the latitudinal gradient. While nitrogen deposition is elevated in the south, the increase in temperatures during recent decades has been larger in the north. Hence, we suggest that different processes in the north and south have produced similar vegetation changes along the latitudinal gradient. There was, however, a sharp increase in compositional change at high deposition, indicating a threshold effect in the response. Instead of a positive feed-back loop caused by the tree layer, an increase in canopy cover reduced the changes in composition of the ground vegetation, whereas a decrease in canopy cover lead to larger changes. Increased natural disturbances of the tree layer due to, for example, pathogens or climate is a predicted outcome of climate change. Hence, these results may have important implications for predictions of long-term effects of increased temperature on peatland vegetation.

Keywords
bog, bryophytes, climate change, conifers, ericoids, forbs, graminoids, mire, nitrogen deposition, peatland, sedges
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-315837 (URN)10.1002/ecy.1627 (DOI)000391862900023 ()28052390 (PubMedID)
Available from: 2017-02-21 Created: 2017-02-21 Last updated: 2017-11-29Bibliographically approved
Moor, H., Rydin, H., Hylander, K., Nilsson, M. B., Lindborg, R. & Norberg, J. (2017). Towards a trait-based ecology of wetland vegetation. Journal of Ecology, 105(6), 1623-1635
Open this publication in new window or tab >>Towards a trait-based ecology of wetland vegetation
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2017 (English)In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 105, no 6, p. 1623-1635Article, review/survey (Refereed) Published
Abstract [en]

1. Functional traits mechanistically capture plant responses to environmental gradients as well asplant effects on ecosystem functioning. Yet most trait-based theory stems from terrestrial systemsand extension to other habitats can provide new insights.

2. Wetlands differ from terrestrial systems in conditions (e.g. soil water saturation, anoxia, pHextremes), plant adaptations (e.g. aerenchyma, clonality, ubiquity of bryophytes) and important pro-cesses (e.g. denitrificati on, peat accumulation, methane emission). Wetland plant adaptations andtrait (co-)variation can be situated along major plant trait trade-off axes (e.g. the resource economicsspectrum), but soil saturation represents a complex stress gradient beyond a simple extension ofcommonly studied water availability gradi ents.

3. Traits that affect ecosystem functioning overlap with patterns in terrestrial systems . But wetland-specific traits that mediate plant effects on soil redox conditions, microbial communities and onwater flow, as well as trait spectra of mosses, vary among wetland types.

4. Synthesis. With increasing availability of quantitative plant traits a trait-based ecology of wetlandsis emerging, with the potential to advance process-based understanding and prediction. We providean inte ractive cause-and-effect framework that may guide research efforts to disentangle the multipleinteracti ng processes involved in scaling from environmental conditions to ecosystem functioni ngvia plant communities.

National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-325257 (URN)10.1111/1365-2745.12734 (DOI)000413341700016 ()
Available from: 2017-06-22 Created: 2017-06-22 Last updated: 2018-03-22Bibliographically approved
Udd, D., Sundberg, S. & Rydin, H. (2016). Multi-species competition experiments with peatland bryophytes. Journal of Vegetation Science, 27(1), 165-175
Open this publication in new window or tab >>Multi-species competition experiments with peatland bryophytes
2016 (English)In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 27, no 1, p. 165-175Article in journal (Refereed) Published
Abstract [en]

Question

Species interactions are one of the processes determining composition of plant communities. We used the community density series method to study competition in a multi-species community of bryophytes common in calcareous fens. The succession of mires is driven bySphagnum species, which are supposedly superior to brown mosses in competition for resources and space, but little is known about the environmental conditions in which brown mosses can prevail when subject to neighbour interactions. How are interactions among peatland bryophytes affected by the environment?

Location

Field and garden experiments near Uppsala in mid-eastern Sweden.

Methods

To examine the effects of environment on competition and competitive hierarchies we assembled multi-species communities of ten bryophyte species from shoot fragments (brown mosses and Sphagnum species) at two densities and grew them on three types of peat (representing poor, intermediate and rich fens) under dry or wet conditions in a garden experiment and along pH and wetness gradients in the field.

Results

A multivariate analysis of the garden experiment showed that community composition was affected by peat type and wetness and their interactions. The brown mosses performed better in wet and rich fens, the Sphagnum species in drier and poorer fens. The Sphagnumspecies were overall the best competitors.

Conclusions

The experiments demonstrated contrasting responses of brown mosses and Sphagnum to properties of the microhabitat. Sphagnumspecies were generally less affected by competition than the brown mosses. Sphagnum species were competitive in habitats typically dominated by brown mosses and even responded positively to crowding. This can explain why Sphagnum can invade calcareous fens. In contrast, brown mosses performed poorly in habitats more typical of Sphagnum species.

Keywords
Brown mosses, Calcareous fen, Common garden experiment, Density, Field experiment, pH, Relative growth rate (RGR), Sphagnum, Wetness
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-259194 (URN)10.1111/jvs.12322 (DOI)000367816400019 ()
External cooperation:
Funder
Swedish Research Council FormasSwedish Research Council
Available from: 2015-07-29 Created: 2015-07-29 Last updated: 2017-12-04Bibliographically approved
Bengtsson, F., Granath, G. & Rydin, H. (2016). Photosynthesis, growth, and decay traits in Sphagnum – a multispecies comparison. Ecology and Evolution, 6(10), 3325-3341
Open this publication in new window or tab >>Photosynthesis, growth, and decay traits in Sphagnum – a multispecies comparison
2016 (English)In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 6, no 10, p. 3325-3341Article in journal (Refereed) Published
Abstract [en]

Peat mosses (Sphagnum) largely govern carbon sequestration in Northern Hemisphere peatlands. We investigated functional traits related to growth and decomposition in Sphagnum species. We tested the importance of environment and phylogeny in driving species traits and investigated trade-offs among them. We selected 15 globally important Sphagnum species, representing four sections (subgenera) and a range of peatland habitats. We measured rates of photosynthesis and decomposition in standard laboratory conditions as measures of innate growth and decay potential, and related this to realized growth, production, and decomposition in their natural habitats. In general, we found support for a trade-off between measures of growth and decomposition. However, the relationships are not strong, with r ranging between 0.24 and 0.45 for different measures of growth versus decomposition. Using photosynthetic rate to predict decomposition in standard conditions yielded R2 = 0.20. Habitat and section (phylogeny) affected the traits and the trade-offs. In a wet year, species from sections Cuspidata and Sphagnum had the highest production, but in a dry year, differences among species, sections, and habitats evened out. Cuspidata species in general produced easily decomposable litter, but their decay in the field was hampered, probably due to near-surface anoxia in their wet habitats. In a principal components analysis, PCA, photosynthetic capacity, production, and laboratory decomposition acted in the same direction. The species were imperfectly clustered according to vegetation type and phylogeny, so that some species clustered with others in the same section, whereas others clustered more clearly with others from similar vegetation types. Our study includes a wider range of species and habitats than previous trait analyses in Sphagnum and shows that while the previously described growth–decay trade-off exists, it is far from perfect. We therefore suggest that our species-specific trait measures offer opportunities for improvements of peatland ecosystem models. Innate qualities measured in laboratory conditions translate differently to field responses. Most dramatically, fast-growing species could only realize their potential in a wet year. The same species decompose fast in laboratory, but their decomposition was more retarded in the field than that of other species. These relationships are crucial for understanding the long-term dynamics of peatland communities.

National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-284287 (URN)10.1002/ece3.2119 (DOI)000376646700024 ()27103989 (PubMedID)
Funder
Swedish Research CouncilSwedish Research Council FormasThe Royal Swedish Academy of Sciences
Available from: 2016-04-16 Created: 2016-04-16 Last updated: 2017-11-30Bibliographically approved
Johnson, M. G., Granath, G., Tahvanainen, T., Pouliot, R., Stenoien, H. K., Rochefort, L., . . . Shaw, A. J. (2015). Evolution of niche preference in Sphagnum peat mosses. Evolution, 69(1), 90-103
Open this publication in new window or tab >>Evolution of niche preference in Sphagnum peat mosses
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2015 (English)In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 69, no 1, p. 90-103Article in journal (Refereed) Published
Abstract [en]

Peat mosses (Sphagnum) are ecosystem engineersspecies in boreal peatlands simultaneously create and inhabit narrow habitat preferences along two microhabitat gradients: an ionic gradient and a hydrological hummock-hollow gradient. In this article, we demonstrate the connections between microhabitat preference and phylogeny in Sphagnum. Using a dataset of 39 species of Sphagnum, with an 18-locus DNA alignment and an ecological dataset encompassing three large published studies, we tested for phylogenetic signal and within-genus changes in evolutionary rate of eight niche descriptors and two multivariate niche gradients. We find little to no evidence for phylogenetic signal in most component descriptors of the ionic gradient, but interspecific variation along the hummock-hollow gradient shows considerable phylogenetic signal. We find support for a change in the rate of niche evolution within the genusthe hummock-forming subgenus Acutifolia has evolved along the multivariate hummock-hollow gradient faster than the hollow-inhabiting subgenus Cuspidata. Because peat mosses themselves create some of the ecological gradients constituting their own habitats, the classic microtopography of Sphagnum-dominated peatlands is maintained by evolutionary constraints and the biological properties of related Sphagnum species. The patterns of phylogenetic signal observed here will instruct future study on the role of functional traits in peatland growth and reconstruction.

Keywords
Bryophyte, comparative methods, peatland ecology, phylogenetic signal
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-243667 (URN)10.1111/evo.12547 (DOI)000347462800007 ()25319183 (PubMedID)
Available from: 2015-02-20 Created: 2015-02-11 Last updated: 2017-12-04Bibliographically approved
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