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  • 1.
    Backéus, Ingvar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Var Sellingaffären kulmen på en sekellång botanisk konflikt?2018In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 112, no 6, p. 380-393Article in journal (Refereed)
    Abstract [en]

    The 1950s saw a series of miscarriages of justice against public persons in Sweden. In one of these, the Royal Swedish Academy of Sciences tried to force Olof Selling from his professorship in paleobotany at the Swedish Museum of Natural History, on the basis of mental illness, but this failed after a long and public calamity. In his book Naturen inför rätta [Nature facing trial], Keith Wijkander (2017) claims that Selling was the victimof a century-long conflict between botanists in Uppsala and Stockholm,and places Selling in the Uppsala camp. We try to give a more balanced picture of the relationships between plant ecology in Uppsala and Stockholm during the early 20th century. R. Sernander, L.-G. Romell and G. E. Du Rietz are among the main actors. The fierce debates between the two camps make this an interesting period in Swedish botany.

  • 2.
    Bengtsson, Fia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Granath, Gustaf
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Cronberg, Nils
    Department of Biology, Lund University , Ecology Building, SE-22362 Lund, Sweden.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Mechanisms behind species-specific water economy responses to water level drawdown in peat mosses2020In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 126, no 2, p. 219-230Article in journal (Refereed)
    Abstract [en]

    Background and Aims

    The ecosystem engineers Sphagnum (peat mosses) are responsible for sequestering a large proportion of carbon in northern peatlands. Species may respond differently to hydrological changes, and water level changes may lead to vegetation shifts in peatlands, causing them to revert from sinks to sources of carbon. We aimed to compare species-specific responses to water level drawdown within Sphagnum, and investigate which traits affect water economy in this genus.

    Methods

    In a mesocosm experiment, we investigated how water level drawdown affected water content (WC) in the photosynthetically active apex of the moss and maximum quantum yield of photosystem II (i.e. Fv/Fm) of 13 Sphagnum species. Structural traits were measured, and eight anatomical traits were quantified from scanning electron microscopy micrographs.

    Key Results

    Mixed-effects models indicated that at high water level, large leaves were the most influential predictor of high WC, and at low water level WC was higher in species growing drier in the field, with larger hyaline cell pore sizes and total pore areas associated with higher WC. Higher stem and peat bulk density increased WC, while capitulum mass per area and numerical shoot density did not. We observed a clear positive relationship between Fv/Fm and WC in wet-growing species.

    Conclusions

    While we found that most hummock species had a relatively high water loss resistance, we propose that some species are able to maintain a high WC at drawdown by storing large amounts of water at a high water level. Our result showing that leaf traits are important warrants further research using advanced morphometric methods. As climate change may lead to more frequent droughts and thereby water level drawdowns in peatlands, a mechanistic understanding of species-specific traits and responses is crucial for predicting future changes in these systems.

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  • 3.
    Bengtsson, Fia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Granath, Gustaf
    Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Photosynthesis, growth, and decay traits in Sphagnum – a multispecies comparison2016In: Ecology and Evolution, E-ISSN 2045-7758, Vol. 6, no 10, p. 3325-3341Article in journal (Refereed)
    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.

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  • 4.
    Bengtsson, Fia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Baltzer, Jennifer L.
    Wilfrid Laurier Univ, Biol Dept, Waterloo, ON, Canada..
    Bragazza, Luca
    Univ Ferrara, Dept Life Sci & Biotechnol, Ferrara, Italy.;WSL Site Lausanne, Swiss Fed Inst Forest Snow & Landscape Res, Lausanne, Switzerland.;Ecole Polytech Fed Lausanne EPFL, Sch Architecture Civil & Environm Engn ENAC, Lab Ecol Syst ECOS, Lausanne, Switzerland..
    Bu, Zhao-Jun
    Northeast Normal Univ, Inst Peat & Mire Res, State Environm Protect Key Lab Wetland Ecol & Veg, Changchun, Peoples R China.;Northeast Normal Univ, Sch Geog Sci, Key Lab Geog Proc & Ecol Secur Changbai Mt, Minist Educ, Changchun, Peoples R China..
    Caporn, Simon J. M.
    Manchester Metropolitan Univ, Dept Nat Sci, Manchester, Lancs, England..
    Dorrepaal, Ellen
    Umeå Univ, Dept Ecol & Environm Sci, Climate Impacts Res Ctr, Abisko, Sweden..
    Flatberg, Kjell Ivar
    Norwegian Univ Sci & Technol, NTNU Univ Museum, Trondheim, Norway..
    Galanina, Olga
    St Petersburg State Univ, Inst Earth Sci, St Petersburg, Russia.;Russian Acad Sci, Komarov Bot Inst, St Petersburg, Russia..
    Galka, Mariusz
    Univ Lodz, Fac Biol & Environm Protect, Dept Geobotany & Plant Ecol, Lodz, Poland..
    Ganeva, Anna
    Bulgarian Acad Sci, Inst Biodivers & Ecosyst Res, Sofia, Bulgaria..
    Goia, Irina
    Babes Bolyai Univ, Fac Biol & Geol, Dept Taxon & Ecol, Cluj Napoca, Romania..
    Goncharova, Nadezhda
    Russian Acad Sci, Ural Branch, Inst Biol, Komi Sci Ctr, Syktyvkar, Russia..
    Hajek, Michal
    Masaryk Univ, Dept Bot & Zool, Fac Sci, Brno, Czech Republic..
    Haraguchi, Akira
    Univ Kitakyushu, Dept Biol, Kitakyushu, Fukuoka, Japan..
    Harris, Lorna I.
    McGill Univ, Dept Geog, Montreal, PQ, Canada..
    Humphreys, Elyn
    Carleton Univ, Dept Geog & Environm Studies, Ottawa, ON, Canada..
    Jirousek, Martin
    Masaryk Univ, Dept Bot & Zool, Fac Sci, Brno, Czech Republic.;Mendel Univ Brno, Fac AgriSci, Dept Plant Biol, Brno, Czech Republic..
    Kajukalo, Katarzyna
    Adam Mickiewicz Univ, Climate Change Ecol Res Unit, Poznan, Poland..
    Karofeld, Edgar
    Univ Tartu, Inst Ecol & Earth Sci, Tartu, Estonia..
    Koronatova, Natalia G.
    Russian Acad Sci, Inst Soil Sci & Agrochem, Lab Biogeocenol, Siberian Branch, Novosibirsk, Russia..
    Kosykh, Natalia P.
    Russian Acad Sci, Inst Soil Sci & Agrochem, Lab Biogeocenol, Siberian Branch, Novosibirsk, Russia..
    Laine, Anna M.
    Univ Eastern Finland, Sch Forest Sci, Peatland & Soil Ecol Grp, Joensuu, Finland.;Univ Oulu, Dept Ecol & Genet, Oulu, Finland..
    Lamentowicz, Mariusz
    Adam Mickiewicz Univ, Climate Change Ecol Res Unit, Poznan, Poland..
    Lapshina, Elena
    Yugra State Univ, Khanty Mansiysk, Russia..
    Limpens, Juul
    Wageningen Univ, Plant Ecol & Nat Conservat Grp, Wageningen, Netherlands..
    Linkosalmi, Maiju
    Finnish Meteorol Inst, Helsinki, Finland..
    Ma, Jin-Ze
    Northeast Normal Univ, Inst Peat & Mire Res, State Environm Protect Key Lab Wetland Ecol & Veg, Changchun, Peoples R China.;Northeast Normal Univ, Sch Geog Sci, Key Lab Geog Proc & Ecol Secur Changbai Mt, Minist Educ, Changchun, Peoples R China..
    Mauritz, Marguerite
    No Arizona Univ, Dept Biol Sci, Ctr Ecosyst Sci & Soc Ecoss, Box 5640, Flagstaff, AZ 86011 USA..
    Mitchell, Edward A. D.
    Univ Neuchatel, Inst Biol, Lab Soil Biodivers, Neuchatel, Switzerland.;Jardin Bot Neuchatel, Neuchatel, Switzerland..
    Munir, Tariq M.
    Univ Calgary, Dept Geog, Calgary, AB, Canada.;Univ Saskatchewan, Dept Geog & Planning, Saskatoon, SK, Canada..
    Natali, Susan M.
    Woods Hole Res Ctr, Falmouth, MA USA..
    Natcheva, Rayna
    Bulgarian Acad Sci, Inst Biodivers & Ecosyst Res, Sofia, Bulgaria..
    Payne, Richard J.
    Univ York, Environm & Geog, York, N Yorkshire, England.;Lomonosov Moscow State Univ, Moscow, Russia..
    Philippov, Dmitriy A.
    Russian Acad Sci, Papanin Inst Biol Inland Waters, Borok, Russia..
    Rice, Steven K.
    Union Coll, Dept Biol Sci, Schenectady, NY 12308 USA..
    Robinson, Sean
    SUNY Coll Oneonta, Dept Biol, Oneonta, NY USA..
    Robroek, Bjorn J. M.
    Radboud Univ Nijmegen, Inst Water & Wetland Res, Aquat Ecol & Environm Biol, Nijmegen, Netherlands..
    Rochefort, Line
    Laval Univ, Dept Plant Sci, Quebec City, PQ, Canada.;Laval Univ, Ctr Northern Studies, Quebec City, PQ, Canada..
    Singer, David
    Univ Neuchatel, Inst Biol, Lab Soil Biodivers, Neuchatel, Switzerland.;Univ Sao Paulo, Inst Biosci, Dept Zool, Sao Paulo, Brazil..
    Stenoien, Hans K.
    Norwegian Univ Sci & Technol, NTNU Univ Museum, Trondheim, Norway..
    Tuittila, Eeva-Stiina
    Univ Eastern Finland, Sch Forest Sci, Peatland & Soil Ecol Grp, Joensuu, Finland..
    Vellak, Kai
    Univ Tartu, Inst Ecol & Earth Sci, Tartu, Estonia..
    Waddington, James Michael
    McMaster Univ, Sch Earth Environm & Soc, Hamilton, ON, Canada..
    Granath, Gustaf
    Uppsala Univ, Dept Ecol & Genet, Uppsala, Sweden..
    Environmental drivers ofSphagnumgrowth in peatlands across the Holarctic region2021In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 109, no 1, p. 417-431Article in journal (Refereed)
    Abstract [en]

    The relative importance of global versus local environmental factors for growth and thus carbon uptake of the bryophyte genusSphagnum-the main peat-former and ecosystem engineer in northern peatlands-remains unclear. We measured length growth and net primary production (NPP) of two abundantSphagnumspecies across 99 Holarctic peatlands. We tested the importance of previously proposed abiotic and biotic drivers for peatland carbon uptake (climate, N deposition, water table depth and vascular plant cover) on these two responses. Employing structural equation models (SEMs), we explored both indirect and direct effects of drivers onSphagnumgrowth. Variation in growth was large, but similar within and between peatlands. Length growth showed a stronger response to predictors than NPP. Moreover, the smaller and denserSphagnum fuscumgrowing on hummocks had weaker responses to climatic variation than the larger and looserSphagnum magellanicumgrowing in the wetter conditions. Growth decreased with increasing vascular plant cover within a site. Between sites, precipitation and temperature increased growth forS. magellanicum. The SEMs indicate that indirect effects are important. For example, vascular plant cover increased with a deeper water table, increased nitrogen deposition, precipitation and temperature. These factors also influencedSphagnumgrowth indirectly by affecting moss shoot density. Synthesis. Our results imply that in a warmer climate,S. magellanicumwill increase length growth as long as precipitation is not reduced, whileS. fuscumis more resistant to decreased precipitation, but also less able to take advantage of increased precipitation and temperature. Such species-specific sensitivity to climate may affect competitive outcomes in a changing environment, and potentially the future carbon sink function of peatlands.

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  • 5.
    Bengtsson, Fia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Granath, Gustaf
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Environmental drivers of Sphagnum growth in mires across the Holarctic regionManuscript (preprint) (Other academic)
  • 6.
    Bengtsson, Fia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Hajek, Tomas
    Univ South Bohemia, Dept Expt Plant Biol, Fac Sci, Branisovska 1760, CZ-37005 Ceske Budejovice, Czech Republic;Czech Acad Sci, Inst Bot, Dept Funct Ecol, Dukelska 135, CZ-37982 Trebon, Czech Republic.
    Biochemical determinants of litter quality in 15 species of Sphagnum2018In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 425, no 1-2, p. 161-176Article in journal (Refereed)
    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.

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  • 7. Bengtsson, J.
    et al.
    Fagerström, T.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Competition and coexistence in plant communities1994In: Trends in Ecology & Evolution, Vol. 9, p. 246-250Article in journal (Refereed)
  • 8. Berendse, F
    et al.
    van Breemen, N
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Buttler, A
    Heijmans, M
    Hoosbeek, MR
    Lee, JA
    Mitchell, E
    Saarinen, T
    Vasander, H
    Wallen, B
    Raised atmospheric CO2 levels and increased N deposition cause shifts in plant species composition and production in Sphagnum bogs2001In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 7, no 5, p. 591-598Article in journal (Refereed)
    Abstract [en]

    Part of the missing sink in the global CO2 budget has been attributed to the positive effects of CO2 fertilization and N deposition on carbon sequestration in Northern Hemisphere terrestrial ecosystems. The genus Sphagnum is one of the most important groups of plant species sequestrating carbon in temperate and northern bog ecosystems, because of the low decomposability of the dead material it produces. The effects of raised CO2 and increased atmospheric N deposition on growth of Sphagnum and other plants were studied in bogs at four sites across Western Europe. Contrary to expectations, elevated CO2 did not significantly affect Sphagnum biomass growth. Increased N deposition reduced Sphagnum mass growth, because it increased the cover of vascular plants and the tall moss Polytrichum strictum. Such changes in plant species composition may decrease carbon sequestration in Sphagnum-dominated bog ecosystems.

  • 9. Borgegård, S.-O.
    et al.
    Morander, R.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Vegetationen på skär bildade vid Hjälmarsänkningen i hundraårigt perspektiv1987In: Årsbok 1987, Hembygdsföreningen Arboga Minne , 1987Chapter in book (Refereed)
  • 10. Borgegård, S.-O.
    et al.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Biomass, root penetration and heavy metal uptake in birch in a soil cover over copper tailings1989In: Journal of Applied Ecology, Vol. 26, p. 585-595Article in journal (Refereed)
  • 11. Borgegård, S.-O.
    et al.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Utilization of waste products and inorganic fertilizer in the restoration of iron-mine tailings1989In: Journal of Applied Ecology, Vol. 26, p. 1083-1088Article in journal (Refereed)
  • 12. Bragazza, L
    et al.
    Limpens, J
    Gerdol, R
    Grosvernier, P
    Hájek, M
    Hájek, T
    Hajkova, P
    Hansen, I
    Iacumin, P
    Kutnar, L
    Rydin, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Plant Ecology.
    Tahvanainen, T
    Nitrogen concentration and delta(15)N signature of ombrotrophic Sphagnum mosses at different N deposition in Europe2005In: Global Change Biology, Vol. 11, p. 106-114Article in journal (Refereed)
  • 13. Bragazza, L
    et al.
    Rydin, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Plant Ecology.
    Gerdol, R
    Multiple gradients in mire vegetation: a comparison of a Swedish and an Italian bog2005In: Plant Ecology, Vol. 177, p. 223-236Article in journal (Refereed)
  • 14. Bragazza, L
    et al.
    Tahvanainen, T
    Kutnar, L
    Rydin, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Limpens, J
    Nutritional constraints in ombrotrophic Sphagnum plants under increasing atmospheric nitrogen deposition in Europe2004In: New Phytologist, Vol. 163, p. 609-616Article in journal (Refereed)
  • 15. Bragazza, Luca
    et al.
    Freeman, Chris
    Jones, Timothy
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Limpens, Juul
    Fenner, Nathalie
    Ellis, Tim
    Gerdol, Renato
    Hajek, Michal
    Hajek, Tomas
    Lacumin, Paola
    Kutnar, Lado
    Tahvanainen, Teemu
    Toberman, Hannah
    Atmospheric nitrogen deposition promotes carbon loss from peat bogs2006In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 103, no 51, p. 19386-19389Article in journal (Refereed)
    Abstract [en]

    Peat bogs have historically represented exceptional carbon (C) sinks because of their extremely low decomposition rates and consequent accumulation of plant remnants as peat. Among the factors favoring that peat accumulation, a major role is played by the chemical quality of plant litter itself, which is poor in nutrients and characterized by polyphenols with a strong inhibitory effect on microbial breakdown. Because bogs receive their nutrient supply solely from atmospheric deposition, the global increase of atmospheric nitrogen (N) inputs as a consequence of human activities could potentially alter the litter chemistry with important, but still unknown, effects on their C balance. Here we present data showing the decomposition rates of recently formed litter peat samples collected in nine European countries under a natural gradient of atmospheric N deposition from approximate to 0.2 to 2 g center dot m(-2)center dot yr(-1). We found that enhanced decomposition rates for material accumulated under higher atmospheric N supplies resulted in higher carbon dioxide (CO2) emissions and dissolved organic carbon release. The increased IN availability favored microbial decomposition (i) by removing N constraints on microbial metabolism and (ii) through a chemical amelioration of litter peat quality with a positive feedback on microbial enzymatic activity. Although some uncertainty remains about whether decay-resistant Sphagnum will continue to dominate litter peat, our data indicate that, even without such changes, increased N deposition poses a serious risk to our valuable peatland C sinks.

  • 16. Bragazza, Luca
    et al.
    Gerdol, Renato
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology.
    Effects of mineral and nutrient input on mire bio-geochemistry in two geographical regions2003In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 91, no 3, p. 417-426Article in journal (Refereed)
    Abstract [en]

    1 We assessed the role of climatic conditions and the effects of different, long-term atmospheric depositions in controlling the mineral and nutrient contents in pore-water, surface peat and in living Sphagna at a boreo-nemoral mire in Sweden and an alpine mire in Italy.

    2 The terrestrial contribution of Ca2+, Mg2+ and SO42- in bulk precipitation was much greater at the Italian mire, in accordance with the different bedrock in the region and the higher level of atmospheric pollution.

    3 At both mires, the contribution of bulk precipitation to the concentration of major ions in mire pore-water was much greater in the ombrotrophic than in the minerotrophic part, because of the raised morphology of the mires, which limited the inflow of mineral soil water to the margins. The only ions strongly depleted in mire pore-water compared with precipitation were K+, NO3- and NH4+ and these were therefore limiting to plant growth.

    4 Higher SO42- concentration in pore-water at the Swedish mire, which experienced lower atmospheric inputs of sulphate, was probably caused by oxidative processes during a long dry period in the summer before sampling.

    5 Higher rates of NO3-, NH4+, as well as SO42- atmospheric inputs at the Italian mire were reflected in significantly higher N and, partly, S concentrations in ombrotrophic Sphagna. Higher NO3- concentration in pore-water at the Italian mire was associated with a lower N retention coefficient of the ombrotrophic Sphagnum plants, suggesting a reduced nitrogen filtering ability of the moss layer.

  • 17. Bu, Z
    et al.
    Yang, Y
    Rydin, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Plant Ecology.
    Lang, H
    Age structures of modules of clonal peatland sedge Carex middendorffii2005In: Chinese Geographical Science, Vol. 15, p. 269-274Article in journal (Refereed)
  • 18. Bu, Zhaojun
    et al.
    Chen, Xu
    Rydin, Hakan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Wang, Shengzhong
    Ma, Jinze
    Zeng, Jing
    Performance of four mosses in a reciprocal transplant experiment: implications for peatland succession in NE China2013In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820, Vol. 35, p. 220-227Article in journal (Refereed)
    Abstract [en]

    Sphagnum dominates the moss layer in northern peatlands, but its dominance has decreased while there has been an expansion of other moss genera in some peatlands of NE China since the 1960s. To discover the mechanisms underlying this succession, we performed a four-month reciprocal transplant experiment in Hani Peatland with three Sphagnum species, Sphagnum palustre, S. magellanicum, and S. fuscum and one other moss Polytrichum strictum. Performance of the four mosses and the environmental factors: height above water table (HWT), vascular plant cover and pH, electrical conductivity, base cations, and N and P concentrations in water in the four moss habitats were measured. Biomass production in S. palustre was negatively affected by HWT. Phosphorus had a positive effect on biomass production in S. magellanicum and Polytrichum. None of the environmental factors had any effect on S. fuscum. Overall, the three Sphagnum species deteriorated in P. strictum hummocks, while P. strictum exhibited a wider ecological amplitude and maintained or increased its vigour levels in Sphagnum hummocks. Biomass production in S. palustre and S. magellanicum was negatively affected by P. strictum indicating the competitive ability of P. strictum. Our results suggest that its wide ecological amplitude and competitive ability may explain why P. strictum can expand and replace Sphagnum in some northern peatlands.

  • 19. Bu, Zhao-Jun
    et al.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Chen, Xu
    Direct and interaction-mediated effects of environmental changes on peatland bryophytes2011In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 166, no 2, p. 555-563Article in journal (Refereed)
    Abstract [en]

    Ecosystem processes of northern peatlands are largely governed by the vitality and species composition in the bryophyte layer, and may be affected by global warming and eutrophication. In a factorial experiment in northeast China, we tested the effects of raised levels of nitrogen (0, 1 and 2 g m(-2) year(-1)), phosphorus (0, 0.1 and 0.2 g m(-2) year(-1)) and temperature (ambient and +3A degrees C) on Polytrichum strictum, Sphagnum magellanicum and S. palustre, to see if the effects could be altered by inter-specific interactions. In all species, growth declined with nitrogen addition and increased with phosphorus addition, but only P. strictum responded to raised temperature with increased production of side-shoots (branching). In Sphagnum, growth and branching changed in the same direction, but in Polytrichum, the two responses were uncoupled: with nitrogen addition there was a decrease in growth (smaller than in Sphagnum) but an increase in branching; with phosphorus addition growth increased but branching was unaffected. There were no two-way interactions among the P, N and T treatments. With increasing temperature, our results indicate that S. palustre should decrease relative to P. strictum (Polytrichum increased its branching and had a negative neighbor effect on S. palustre). With a slight increase in phosphorus availability, the increase in length growth and production of side-shoots in P. strictum and S. magellanicum may give them a competitive superiority over S. palustre. The negative response in Sphagnum to nitrogen could favor the expansion of vascular plants, but P. strictum may endure thanks to its increased branching.

  • 20. Bu, Zhao-Jun
    et al.
    Zheng, Xing-Xing
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Moore, Tim
    Ma, Jinze
    Facilitation vs. competition: Does interspecific interaction affect drought responses in Sphagnum?2013In: Basic and Applied Ecology, ISSN 1439-1791, E-ISSN 1618-0089, Vol. 14, no 7, p. 574-584Article in journal (Refereed)
    Abstract [en]

    The stress-gradient hypothesis (SGH) predicts that the relative importance of competition decreases and facilitation increases with an increase in abiotic stress. In peatlands, Sphagnum faces the threat of drought and differentiates into hummock species (drought-tolerant) and hollow species. Whether interspecific interaction affects the influence of drought on bryophyte composition in peatlands is unknown. We established an experiment by simulating drought and building bryophyte communities with two hummock species (S. palustre and S. capillifolium) and one hollow species (S. fallax). In all three species, drought decreased biomass production, height increment and side-shoot production. Sphagnum stores water in the hyaline cells, and leaf hyaline cell percentage (HCP) in the two hummock species increased with drought while no effect was found in S. fallax, suggesting that adjusting HCP is not an effective response to drought for the hollow species. Morphological traits and carbon and nitrogen contents in hummock species responded more to drought than in the hollow species, indicating a rapid response in phenotypic plasticity is an important strategy to resist drought in the hummock species. The presence of neighboring Sphagnum species, rather than drought, decreased carbon content for all three species. All three bryophytes showed interaction between drought and neighbor in two or more plant traits. Our study, however, did not support SGH, and there were no changes from competition under wet to facilitation under dry treatments in any of the six species combinations. On the contrary, when S. fallax was the target species, a change from facilitation under wet to competition under dry treatments was observed. The results suggest that hummock species can facilitate hollow species in wet environments but they could suppress hollow species under drought conditions by competing for water resources. Both drought and strong competition are the probable reasons why hollow species rarely grow in hummocks.

  • 21.
    Campbell, Charles
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Granath, Gustaf
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Structural traits of Sphagnum: Interrelationships and implications on water economyManuscript (preprint) (Other academic)
  • 22.
    Campbell, Charles
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    The effects of winter stress on Sphagnum specieswith contrasting macro- and microdistributions2019In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820, Vol. 41, no 3, p. 205-217Article in journal (Refereed)
    Abstract [en]

    Introduction: Sphagnum L. forms much of the ground cover in northern peatlands. Different species show affinities for bioclimatic regions in Europe (oceanic/continental; northern/southern) and species-specific tolerance of winter conditions can be a factor explaining their distribution.

    Methods: We focussed on low temperature in a series of experiments and tested (1) the innate ability of a selection of Sphagnum species to tolerate low temperature in relation to their micro-topographic (wetness) and geographical (climate) distribution; (2) the rate of cold tolerance acquisition; and (3) the ability of species to survive a range of low temperature once cold hardened.

    Key results: Our experiments showed that maximal PSII efficiency (Fv/Fm, chlorophyll fluorescence), growth rates and survival were all negatively affected by sub-zero temperatures. Environmental conditions associated with the onset of winter (colder nights and shorter days) triggered the acquisition of cold tolerance in Sphagnum.

    Conclusions: The results were not unequivocal, but species associated with colder climates were generally more tolerant of sub-zero conditions. Species associated with the wettest and driest ends of the wetness gradient were more consistent in their responses than those in between, with wetter-dwelling species being less sensitive to sub-zero temperature than species found in drier microhabitats. Overall, our results suggest that adaptation to winter conditions contribute to the current distribution patterns of Sphagnum species.

     

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  • 23.
    Campbell, Charles
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Granath, Gustaf
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Trait variation across species distribution boundaries in SphagnumManuscript (preprint) (Other academic)
  • 24. Caruso, Alexandro
    et al.
    Rudolphi, Jörgen
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Positive Edge Effects on Forest-Interior Cryptogams in Clear-Cuts2011In: PLOS ONE, E-ISSN 1932-6203, Vol. 6, no 11, p. e27936-Article in journal (Refereed)
    Abstract [en]

    Biological edge effects are often assessed in high quality focal habitats that are negatively influenced by human-modified low quality matrix habitats. A deeper understanding of the possibilities for positive edge effects in matrix habitats bordering focal habitats (e.g. spillover effects) is, however, essential for enhancing landscape-level resilience to human alterations. We surveyed epixylic (dead wood inhabiting) forest-interior cryptogams (lichens, bryophytes, and fungi) associated with mature old-growth forests in 30 young managed Swedish boreal forest stands bordering a mature forest of high conservation value. In each young stand we registered species occurrences on coarse dead wood in transects 0-50 m from the border between stand types. We quantified the effect of distance from the mature forest on the occurrence of forest-interior species in the young stands, while accounting for local environment and propagule sources. For comparison we also surveyed epixylic open-habitat (associated with open forests) and generalist cryptogams. Species composition of epixylic cryptogams in young stands differed with distance from the mature forest: the frequency of occurrence of forest-interior species decreased with increasing distance whereas it increased for open-habitat species. Generalists were unaffected by distance. Epixylic, boreal forest-interior cryptogams do occur in matrix habitats such as clear-cuts. In addition, they are associated with the matrix edge because of a favourable microclimate closer to the mature forest on southern matrix edges. Retention and creation of dead wood in clear-cuts along the edges to focal habitats is a feasible way to enhance the long-term persistence of epixylic habitat specialists in fragmented landscapes. The proposed management measures should be performed in the whole stand as it matures, since microclimatic edge effects diminish as the matrix habitat matures. We argue that management that aims to increase habitat quality in matrix habitats bordering focal habitats should increase the probability of long-term persistence of habitat specialists.

  • 25. Colson, Daniel W.
    et al.
    Morris, Paul J.
    Smith, Mark W.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Granath, Gustaf
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Quincey, Duncan J.
    Six Decades of Changes in Pool Characteristics on a Concentric-Patterned Raised Bog2023In: Ecosystems, ISSN 1432-9840, E-ISSN 1435-0629Article in journal (Refereed)
    Abstract [en]

    Raised bogs are wetland ecosystems which, under the right climatic conditions, feature patterns of pool hollows and hummock ridges. The relative cover and the spatial arrangement of pool and ridge microforms are thought to be influential on peatland atmosphere carbon gas fluxes and plant biodiversity. The mechanisms responsible for the formation and maintenance of pools, and the stability of these features in response to warming climates, remain topics of ongoing research. We employed historical aerial imagery, combined with a contemporary uncrewed aerial vehicle survey, to study 61 years of changes in pools at a patterned raised bog in central Sweden. We used a pool inheritance method to track individual pools between image acquisition dates throughout the time series. These data show a rapid loss of open-water pool area during the study period, primarily due to overgrowth of open-water pools by Sphagnum. We postulate that these changes are driven by ongoing climate warming that is accelerating Sphagnum colonisation. Open-water pool area declined by 26.8% during the study period, equivalent to a loss of 1001 m2 y−1 across the 150-hectare site. This is contradictory to an existing theory that states pools are highly stable, once formed, and can only convert to a terrestrial state through catastrophic drainage. The pool inheritance analysis shows that smaller pools are liable to become completely terrestrialised and expire. Our findings form part of a growing body of evidence for the loss of open-water habitats in peatlands across the boreal and elsewhere.

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  • 26. Cronberg, Nils
    et al.
    Rydin, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Sphagnum borde heta torvmossa på svenska2006In: Svensk Botanisk Tidskrift, Vol. 100, p. 299-300Article in journal (Other (popular scientific, debate etc.))
  • 27. Cronberg, Nils
    et al.
    Rydin, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Plant Ecology.
    Torvmossa - ett nygammalt svenskt namn för Sphagnum2005In: Svensk Botanisk Tidskrift, Vol. 99, p. 290-294Article in journal (Refereed)
  • 28. Dahlström, A.
    et al.
    Borgegård, S.-O.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Kärlväxtfloran på nedlagda ängar och åkrar vid torp i Kilsbergen efter 50 och 90 års igenväxning1998In: Svensk Botanisk Tidskrift, Vol. 91, p. 211-226Article in journal (Refereed)
  • 29.
    Dahlström, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Swedish Biodiversity Centre.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Ecological Botany.
    Borgegård, Sven-Olov
    Remnant habitats for grassland species in an abandoned Swedish agricultural landscape2010In: Applied Vegetation Science, ISSN 1402-2001, E-ISSN 1654-109X, Vol. 13, no 3, p. 305-314Article in journal (Refereed)
    Abstract [en]

    Questions: Which factors influence the persistence of vascular grassland plants in long-abandoned (at least 50 yr) arable fields and meadows? What might be the implications of current levels of species richness on abandoned arable fields and meadows for future restoration?

    Location: Forested highlands of Kilsbergen, south central Sweden.

    Methods: The abundance of all vascular plant species was investigated in three habitat types: former arable fields, hay meadows and outlands (pastures) at 27 farms, abandoned for either approximately 50 yr or 90 yr. Time since abandonment, tree cover, soil depth, degree of soil podsol development, size of the infield area and two measures of connectivity were used as predictors for species richness and species composition.

    Results: Former outland had denser tree cover, fewer species and fewer grassland species than former arable fields and hay meadows, irrespective of time since abandonment. Former hay meadows and arable fields with a longer time since abandonment were less rich in species, more wooded and had greater podsolization than meadows and fields abandoned at a later stage. Species richness was higher in hay meadows and arable fields at farms with larger infield area and deeper soils compared with farms with smaller infield area and shallower soils. The greatest richness of species and most open habitat were former arable fields at larger farms abandoned 50 yr before the study. Former arable fields had the highest number of grassland species.

    Conclusion: After 50 yr of abandonment, former arable fields were the most important remnant habitats for grassland species and may be a more promising target for restoration than formerly managed grasslands.

  • 30. Ecke, F
    et al.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Succession on a land uplift coast in relation to plant strategy theory2000In: Annales Botanici Fennici, ISSN 0003-3847, E-ISSN 1797-2442, Vol. 37, no 3, p. 163-171Article in journal (Refereed)
    Abstract [en]

    Plant strategies under succession were evaluated for communities on rising seashores of the northern Gulf of Bothnia, Sweden, representing sites of primary succession. The succession could not be explained by Grime's CSR model. Early successional stages were neither characterized by high incidence of ruderals as proposed for secondary successions, nor by the dominance of stress tolerators, as proposed for primary successions. Short-lived species were almost totally absent. Instead, the shore habitat was characterized by species with an ability to tolerate and vegetatively recover from disturbance. The way in which different species experience one and the same form of stress or disturbance is an important reason why the classification on the basis of stress and disturbance seems to be insufficient to explain the course of this succession. Dominants of early and late successional stages differed with respect to root system, breeding system, leaf longevity and growth form (graminioid, herb).

  • 31. Ekbohm, G.
    et al.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    On estimating the species-area relationship: commenting Loehle1990In: Oikos, Vol. 57, p. 145-146Article in journal (Refereed)
  • 32.
    Emsens, Willem-Jan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics. Univ Antwerp, Dept Biol, Ecosyst Management Res Grp, Univ Pl 1C, B-2610 Antwerp, Belgium.
    Aggenbach, Camiel J. S.
    Univ Antwerp, Dept Biol, Ecosyst Management Res Grp, Univ Pl 1C, B-2610 Antwerp, Belgium;KWR Watercycle Res Inst, POB 1072, NL-3430 BB Nieuwegein, Netherlands.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Smolders, Alfons J. P.
    Radboud Univ Nijmegen, Inst Wetland & Water Res, Dept Aquat Ecol & Environm Biol, Heyendaalseweg 135-1, NL-6525 ED Nijmegen, Netherlands;B WARE Res Ctr, Toernootveld 1, NL-6525 ED Nijmegen, Netherlands.
    van Diggelen, Rudy
    Univ Antwerp, Dept Biol, Ecosyst Management Res Grp, Univ Pl 1C, B-2610 Antwerp, Belgium.
    Competition for light as a bottleneck for endangered fen species: An introduction experiment2018In: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 220, p. 76-83Article in journal (Refereed)
    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.

  • 33.
    Eshghi Sahraei, Shadi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Furneaux, Brendan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Kluting, Kerri
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Zakieh, Mustafa
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics. Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Rosling, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Effects of operational taxonomic unit inference methods on soil microeukaryote community analysis using long‐read metabarcoding2022In: Ecology and Evolution, E-ISSN 2045-7758, Vol. 12, no 3, article id e8676Article in journal (Refereed)
    Abstract [en]

    Long amplicon metabarcoding has opened the door for phylogenetic analysis of the largely unknown communities of microeukaryotes in soil. Here, we amplified and sequenced the ITS and LSU regions of the rDNA operon (around 1500 bp) from grassland soils using PacBio SMRT sequencing. We tested how three different methods for generation of operational taxonomic units (OTUs) effected estimated richness and identified taxa, and how well large-scale ecological patterns associated with shifting environmental conditions were recovered in data from the three methods. The field site at Kungsängen Nature Reserve has drawn frequent visitors since Linnaeus's time, and its species rich vegetation includes the largest population of Fritillaria meleagris in Sweden. To test the effect of different OTU generation methods, we sampled soils across an abrupt moisture transition that divides the meadow community into a Carex acuta dominated plant community with low species richness in the wetter part, which is visually distinct from the mesic-dry part that has a species rich grass-dominated plant community including a high frequency of Fmeleagris. We used the moisture and plant community transition as a framework to investigate how detected belowground microeukaryotic community composition was influenced by OTU generation methods. Soil communities in both moisture regimes were dominated by protists, a large fraction of which were taxonomically assigned to Ciliophora (Alveolata) while 30%–40% of all reads were assigned to kingdom Fungi. Ecological patterns were consistently recovered irrespective of OTU generation method used. However, different methods strongly affect richness estimates and the taxonomic and phylogenetic resolution of the characterized community with implications for how well members of the microeukaryotic communities can be recognized in the data.

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  • 34. Falkengren-Grerup, U.
    et al.
    Ericson, L.
    Gunnarsson, U.
    Nordin, A.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Wallén, B.
    Does nitrogen deposition change the flora?2000In: Effects of nitrogen deposition on forest ecosystems, Stockholm: Naturvårdsverket , 2000Chapter in book (Refereed)
  • 35. Falkengren-Grerup, U.
    et al.
    Ericson, L.
    Gunnarsson, U.
    Nordin, A.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Wallén, B.
    Förändras floran av kvävenedfallet?2000In: Effekter av kvävenedfall på skogsekosystem, Stockholm: Naturvårdsverket , 2000Chapter in book (Refereed)
  • 36.
    Fonturbel, Francisco E.
    et al.
    Pontificia Univ Catolica Valparaiso, Fac Ciencias, Inst Biol, Valparaiso, Chile..
    Osorio, Felipe
    Freelance Consultant, Villarrica, Chile..
    Riffo-Donoso, Valentina
    Univ Chile, Fac Ciencias, Dept Ciencias Ecol, Santiago, Chile..
    Carvallo, Gaston O.
    Pontificia Univ Catolica Valparaiso, Fac Ciencias, Inst Biol, Valparaiso, Chile..
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Cryptic interactions revisited from ecological networks: Mosses as a key link between trees and hummingbirds2021In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 35, no 1, p. 226-238Article in journal (Refereed)
    Abstract [en]

    Ecological interactions are the glue of biodiversity, structuring communities and determining their functionality. However, our knowledge about ecological interactions is usually biased against cryptic interactions (i.e. overlooked interactions involving inconspicuous species). Mosses are a neglected component in community ecology despite being diverse and abundant in boreal and temperate forests. Therefore, the cryptic relationships of trees as hosts for epiphytic mosses, and vertebrates using mosses as nesting material, may have important consequences for community structuring. We built species- and individual-based ecological networks to characterise tree-moss associations in 120 tree individuals representing 13 species, which hosted 19 moss species. We also used those ecological networks to simulate the effects of non-random extinctions due to selective logging, to assess the presence of moss species in hummingbird nests (30 nests), whether these mosses were a subset of those found on the trees if moss diversity varies with tree height and whether these moss-tree relationships are phylogenetically constrained. We found a nested pattern in the tree-moss network. Taller trees were the most connected, with tree height positively related to number of moss species, network degree and centrality. Extinction simulations showed changes in network topology, with the strongest effect from the removal of the most connected tree species. However, tree and moss networks were not influenced by phylogenetic relatedness. The hummingbirdSephanoides sephaniodesselectively collected mosses; the moss species used as nesting material by hummingbirds were a subset of available species. These complex relationships among trees, birds and mosses underpin the importance of neglected components in the community. We found that tree-moss associations were non-random, showing a positive relationship between tree height and moss diversity. Those associations are the reflection of preferences beyond relative abundances in the forest, and the removal of certain tree species (due to selective logging) may have cascade effects in the community. Furthermore, the lack of phylogenetic correspondence suggests that tree-moss associations are governed by ecological factors (host tree preferences). Moss-hummingbird associations are non-random, as hummingbirds (that pollinate these trees) are actively selecting mosses for nest building, stressing the importance of cryptic interactions as a community-structuring process. A freePlain Language Summarycan be found within the Supporting Information of this article.

  • 37.
    Frost, Ingela
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecological Botany.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecological Botany.
    Effects of competition, grazing and cotyledon nutrient supply on growth of Quercus robur seedlings1997In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 79, no 1, p. 53-58Article in journal (Refereed)
    Abstract [en]

    In this greenhouse experiment we examined how competition and herbivory affects the growth of Quercus robur seedlings and if the cotyledon nutrient reserve is of importance for survival and growth during unfavourable conditions. We planted oak seedlings with or without a strong competitor (grass turf) and subjected them to factorial grazing and cotyledon removal, in a split-plot design. After one growing season (20 weeks) we found large negative main effects from competition, grazing and cotyledon removal on all biomass components of the seedling. Seedling mortality was also significantly increased by competition. We observed an additional effect of cotyledon removal if the seedlings were also grazed or were growing in competition with grass. This gives some support to the hypothesis that cotyledon nutrient reserves are used under unfavourable conditions, but the effect was often relatively small and not detectable in the growth of all plant parts.

  • 38.
    Frost, Ingela
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Spatial pattern and size distribution of the animal-dispersed tree Quercus robur in two spruce-dominated forests2000In: Ecoscience, ISSN 1195-6860, Vol. 7, no 1, p. 38-44Article in journal (Refereed)
    Abstract [en]

    We investigated the degree to which the spatial distribution of oaks (Quercus robur L.) was related to habitat conditions, as reflected by vegetation type and structural features presumed to attract animal dispersers (trails, community borders). We hypothesized that the distribution pattern of oaks, with their potential to establish in many habitats, depends on the behaviour of the dispersing animals to a greater extent than micro-habitat conditions. One 100 m x 100 m plot was surveyed in each of two coniferous forests in east-central Sweden. No adult oak trees grew in the forests; all oaks were considered as dispersed into the plots by animals. We tested whether oak distribution was clumped with spatial autocorrelation analyses and whether oak distribution was related to vegetation type, species composition, tree cover, distance to nearest fertile oak tree, or distance to animal trails. Our study showed that oak trees were also spatially aggregated in a small-scale context. The spatial distribution of seedlings and older trees were associated with species richness and tree cover but not with any specific vegetation type, even though fewer oaks than expected grew in spruce forest habitats. Furthermore, we found that oak trees were associated with trails. There were differences in oak distribution between the two study sites in total number of oaks, the number of first-year seedlings, caches, and oak occurrence in relation to species richness and distance to nearest fertile oak. Seed-dispersing animals seem to be of importance for oak distribution even though animal activities seem to differ between sites.

  • 39.
    Granath, Gustaf
    et al.
    Uppsala universitet, Växtekologi och evolution.
    Rydin, Håkan
    Uppsala universitet, Växtekologi och evolution.
    Baltzer, Jennifer L.
    Biology Department, Wilfrid Laurier University, Waterloo, Canada.
    Bengtsson, Fia
    Uppsala universitet, Växtekologi och evolution.
    Boncek, Nicholas
    Department of Biological Sciences, Union College, Schenectady, NY, USA.
    Bragazza, Luca
    Department of Life Science and Biotechnologies, University of Ferrara, Ferrara, Italy; Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, Lausanne, Switzerland; Ecole Polytechnique Fédérale de Lausanne EPFL, School of Architecture, Civil and Environmental Engineering ENAC, Laboratory of ecological systems ECOS, Station 2, Lausanne, Switzerland.
    Bu, Zhao-Jun
    Institute for Peat and Mire Research, Northeast Normal University, State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Changchun, China; Jilin Provincial Key Laboratory for Wetland Ecological Processes and Environmental Change in the Changbai Mountains, Changchun, China.
    Caporn, Simon J. M.
    School of Science and the Environment, Division of Biology and Conservation Ecology, Manchester Metropolitan University, Manchester, UK.
    Dorrepaal, Ellen
    Climate Impacts Research Centre, Dept. of Ecology and Environmental Science, Umeå University, Abisko, Sweden.
    Galanina, Olga
    Institute of Earth Sciences, St. Petersburg State University, St. Petersburg, Russia; Komarov Botanical Institute Russian Academy of Sciences, St. Petersburg, Russia.
    Galka, Mariusz
    Laboratory of Wetland Ecology and Monitoring & Department of Biogeography and Paleoecology, Adam Mickiewicz University in Poznan, Poznan, Polen.
    Ganeva, Anna
    Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria.
    Gillikin, David P.
    Department of Geology, Union College, Schenectady, NY, USA.
    Goia, Irina
    Babe ̧s-Bolyai University, Faculty of Biology and Geology, Department of Taxonomy and Ecology, Cluj Napoca, Romania.
    Goncharova, Nadezhda
    Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Science, Syktyvkar, Russia.
    Hajek, Michal
    Masaryk Univ, Fac Sci, Dept Bot & Zool, Brno, Czech Republic.
    Haraguchi, Akira
    Univ Kitakyushu, Dept Biol, Kitakyushu, Fukuoka, Japan.
    Harris, Lorna I.
    McGill Univ, Dept Geog, Montreal, Canada.
    Humphreys, Elyn
    Carleton Univ, Dept Geog & Environm Studies, Ottawa, Canada.
    Jirousek, Martin
    Masaryk Univ, Fac Sci, Dept Bot & Zool, Brno, Czech Republic; Mendel Univ Brno, Fac AgriSci, Dept Plant Biol, Brno, Czech Republic.
    Kajukalo, Katarzyna
    Adam Mickiewicz Univ, Lab Wetland Ecol & Monitoring, Poznan, Poland; Adam Mickiewicz Univ, Dept Biogeog & Paleoecol, Poznan, Poland.
    Karofeld, Edgar
    Univ Tartu, Inst Ecol & Earth Sci, Tartu, Estonia.
    Koronatova, Natalia G.
    Russian Acad Sci, Siberian Branch, Inst Soil Sci & Agrochem, Lab Biogeocenol, Novosibirsk, Russia.
    Kosykh, Natalia P.
    Russian Acad Sci, Siberian Branch, Inst Soil Sci & Agrochem, Lab Biogeocenol, Novosibirsk, Russia.
    Lamentowicz, Mariusz
    Adam Mickiewicz Univ, Lab Wetland Ecol & Monitoring, Poznan, Poland; Adam Mickiewicz Univ, Dept Biogeog & Paleoecol, Poznan, Poland.
    Lapshina, Elena
    Yugra State Univ, Khanty Mansiysk, Russia.
    Limpens, Juul
    Wageningen Univ, Plant Ecol & Nat Conservat Grp, Wageningen, Netherlands.
    Linkosalmi, Maiju
    Finnish Meteorol Inst, Helsinki, Finland.
    Ma, Jin-Ze
    Northeast Normal Univ, State Environm Protect Key Lab Wetland Ecol & Veg, Inst Peat & Mire Res, Changchun, Jilin, Peoples R China; Jilin Prov Key Lab Wetland Ecol Proc & Environm C, Changchun, Jilin, Peoples R China.
    Mauritz, Marguerite
    No Arizona Univ, Dept Biol Sci, Ctr Ecosyst Sci & Soc Ecoss, Flagstaff, USA.
    Munir, Tariq M.
    Univ Calgary, Dept Geog, Calgary, Canada; St Marys Univ, Dept Geol, Calgary, Canada.
    Natali, Susan M.
    Woods Hole Res Ctr, Falmouth, USA.
    Natcheva, Rayna
    Bulgarian Acad Sci, Inst Biodivers & Ecosyst Res, Sofia, Bulgaria.
    Noskova, Maria
    Russian Acad Sci, Komarov Bot Inst, St Petersburg, Russia.
    Payne, Richard J.
    Univ York, Environm, York, N Yorkshire, England; Penza State Univ, Penza, Russia.
    Pilkington, Kyle
    Union Coll, Dept Biol Sci, Schenectady, NY USA.
    Robinson, Sean
    SUNY Coll Oneonta, Dept Biol, Oneonta, NY USA.
    Robroek, Bjorn J. M.
    Univ Southampton, Biol Sci, Southampton, Hants, England.
    Rochefort, Line
    Laval Univ, Dept Plant Sci, Quebec City, PQ, Canada; Laval Univ, Ctr Northern Studies, Quebec City, PQ, Canada.
    Singer, David
    Univ Neuchatel, Inst Biol, Lab Soil Biodivers, Neuchatel, Switzerland; Univ Sao Paulo, Inst Biosci, Dept Zool, Sao Paulo, Brazil.
    Stenoien, Hans K.
    Norwegian Univ Sci & Technol, NTNU Univ Museum, Trondheim, Norway.
    Tuittila, Eeva-Stiina
    Univ Eastern Finland, Sch Forest Sci, Peatland & Soil Ecol Grp, Joensuu, Finland.
    Vellak, Kai
    Univ Tartu, Inst Ecol & Earth Sci, Tartu, Estonia.
    Verheyden, Anouk
    Union Coll, Dept Geol, Schenectady, NY USA.
    Waddington, James Michael
    McMaster Univ, Sch Geog & Earth Sci, Hamilton, Canada.
    Rice, Steven K.
    Union Coll, Dept Biol Sci, Schenectady, NY USA.
    Environmental and taxonomic controls of carbon and oxygen stable isotope composition in Sphagnum across broad climatic and geographic ranges2018In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 15, no 16, p. 5189-5202Article in journal (Refereed)
    Abstract [en]

    Rain-fed peatlands are dominated by peat mosses (Sphagnum sp.), which for their growth depend on nutrients, water and CO2 uptake from the atmosphere. As the isotopic composition of carbon (C-12(,)13) and oxygen (O-16(,)18) of these Sphagnum mosses are affected by environmental conditions, Sphagnum tissue accumulated in peat constitutes a potential long-term archive that can be used for climate reconstruction. However, there is inadequate understanding of how isotope values are influenced by environmental conditions, which restricts their current use as environmental and palaeoenvironmental indicators. Here we tested (i) to what extent C and O isotopic variation in living tissue of Sphagnum is speciesspecific and associated with local hydrological gradients, climatic gradients (evapotranspiration, temperature, precipitation) and elevation; (ii) whether the C isotopic signature can be a proxy for net primary productivity (NPP) of Sphagnum; and (iii) to what extent Sphagnum tissue delta O-18 tracks the delta O-18 isotope signature of precipitation. In total, we analysed 337 samples from 93 sites across North America and Eurasia us ing two important peat-forming Sphagnum species (S. magellanicum, S. fuscum) common to the Holarctic realm. There were differences in delta C-13 values between species. For S. magellanicum delta C-13 decreased with increasing height above the water table (HWT, R-2 = 17 %) and was positively correlated to productivity (R-2 = 7 %). Together these two variables explained 46 % of the between-site variation in delta C-13 values. For S. fuscum, productivity was the only significant predictor of delta C-13 but had low explanatory power (total R-2 = 6 %). For delta O-18 values, approximately 90 % of the variation was found between sites. Globally modelled annual delta O-18 values in precipitation explained 69 % of the between-site variation in tissue delta O-18. S. magellanicum showed lower delta O-18 enrichment than S. fuscum (-0.83 %0 lower). Elevation and climatic variables were weak predictors of tissue delta O-18 values after controlling for delta O-18 values of the precipitation. To summarize, our study provides evidence for (a) good predictability of tissue delta O-18 values from modelled annual delta O-18 values in precipitation, and (b) the possibility of relating tissue delta C-13 values to HWT and NPP, but this appears to be species-dependent. These results suggest that isotope composition can be used on a large scale for climatic reconstructions but that such models should be species-specific.

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  • 40.
    Granath, Gustaf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Baltzer, Jennifer L.
    Biology Department, Wilfrid Laurier University, Waterloo, Canada.
    Bengtsson, Fia
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Boncek, Nicholas
    Department of Biological Sciences, Union College, Schenectady, NY, USA.
    Bragazza, Luca
    Department of Life Science and Biotechnologies, University of Ferrara, Ferrara, Italy; Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, Lausanne, Switzerland; Ecole Polytechnique Fédérale de Lausanne EPFL, School of Architecture, Civil and Environmental Engineering ENAC, Laboratory of ecological systems ECOS, Station 2, Lausanne, Switzerland.
    Bu, Zhao-Jun
    Institute for Peat and Mire Research, Northeast Normal University, State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Changchun, China; Jilin Provincial Key Laboratory for Wetland Ecological Processes and Environmental Change in the Changbai Mountains, Changchun, China.
    Caporn, Simon J. M.
    School of Science and the Environment, Division of Biology and Conservation Ecology, Manchester Metropolitan University, Manchester, UK.
    Dorrepaal, Ellen
    Climate Impacts Research Centre, Dept. of Ecology and Environmental Science, Umeå University, Abisko, Sweden.
    Galanina, Olga
    Institute of Earth Sciences, St. Petersburg State University, St. Petersburg, Russia; Komarov Botanical Institute Russian Academy of Sciences, St. Petersburg, Russia.
    Galka, Mariusz
    Laboratory of Wetland Ecology and Monitoring & Department of Biogeography and Paleoecology, Adam Mickiewicz University in Poznan, Poznan, Polen.
    Ganeva, Anna
    Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria.
    Gillikin, David P.
    Department of Geology, Union College, Schenectady, NY, USA.
    Goia, Irina
    Babe ̧s-Bolyai University, Faculty of Biology and Geology, Department of Taxonomy and Ecology, Cluj Napoca, Romania.
    Goncharova, Nadezhda
    Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Science, Syktyvkar, Russia.
    Hajek, Michal
    Masaryk Univ, Fac Sci, Dept Bot & Zool, Brno, Czech Republic.
    Haraguchi, Akira
    Univ Kitakyushu, Dept Biol, Kitakyushu, Fukuoka, Japan.
    Harris, Lorna I.
    McGill Univ, Dept Geog, Montreal, Canada.
    Humphreys, Elyn
    Carleton Univ, Dept Geog & Environm Studies, Ottawa, Canada.
    Jirousek, Martin
    Masaryk Univ, Fac Sci, Dept Bot & Zool, Brno, Czech Republic; Mendel Univ Brno, Fac AgriSci, Dept Plant Biol, Brno, Czech Republic.
    Kajukalo, Katarzyna
    Adam Mickiewicz Univ, Lab Wetland Ecol & Monitoring, Poznan, Poland; Adam Mickiewicz Univ, Dept Biogeog & Paleoecol, Poznan, Poland.
    Karofeld, Edgar
    Univ Tartu, Inst Ecol & Earth Sci, Tartu, Estonia.
    Koronatova, Natalia G.
    Russian Acad Sci, Siberian Branch, Inst Soil Sci & Agrochem, Lab Biogeocenol, Novosibirsk, Russia.
    Kosykh, Natalia P.
    Russian Acad Sci, Siberian Branch, Inst Soil Sci & Agrochem, Lab Biogeocenol, Novosibirsk, Russia.
    Lamentowicz, Mariusz
    Adam Mickiewicz Univ, Lab Wetland Ecol & Monitoring, Poznan, Poland; Adam Mickiewicz Univ, Dept Biogeog & Paleoecol, Poznan, Poland.
    Lapshina, Elena
    Yugra State Univ, Khanty Mansiysk, Russia.
    Limpens, Juul
    Wageningen Univ, Plant Ecol & Nat Conservat Grp, Wageningen, Netherlands.
    Linkosalmi, Maiju
    Finnish Meteorol Inst, Helsinki, Finland.
    Ma, Jin-Ze
    Northeast Normal Univ, State Environm Protect Key Lab Wetland Ecol & Veg, Inst Peat & Mire Res, Changchun, Jilin, Peoples R China; Jilin Prov Key Lab Wetland Ecol Proc & Environm C, Changchun, Jilin, Peoples R China.
    Mauritz, Marguerite
    No Arizona Univ, Dept Biol Sci, Ctr Ecosyst Sci & Soc Ecoss, Flagstaff, USA.
    Munir, Tariq M.
    Univ Calgary, Dept Geog, Calgary, Canada; St Marys Univ, Dept Geol, Calgary, Canada.
    Natali, Susan M.
    Woods Hole Res Ctr, Falmouth, USA.
    Natcheva, Rayna
    Bulgarian Acad Sci, Inst Biodivers & Ecosyst Res, Sofia, Bulgaria.
    Noskova, Maria
    Russian Acad Sci, Komarov Bot Inst, St Petersburg, Russia.
    Payne, Richard J.
    Univ York, Environm, York, N Yorkshire, England; Penza State Univ, Penza, Russia.
    Pilkington, Kyle
    Union Coll, Dept Biol Sci, Schenectady, NY USA.
    Robinson, Sean
    SUNY Coll Oneonta, Dept Biol, Oneonta, NY USA.
    Robroek, Bjorn J. M.
    Univ Southampton, Biol Sci, Southampton, Hants, England.
    Rochefort, Line
    Laval Univ, Dept Plant Sci, Quebec City, PQ, Canada; Laval Univ, Ctr Northern Studies, Quebec City, PQ, Canada.
    Singer, David
    Univ Neuchatel, Inst Biol, Lab Soil Biodivers, Neuchatel, Switzerland; Univ Sao Paulo, Inst Biosci, Dept Zool, Sao Paulo, Brazil.
    Stenoien, Hans K.
    Norwegian Univ Sci & Technol, NTNU Univ Museum, Trondheim, Norway.
    Tuittila, Eeva-Stiina
    Univ Eastern Finland, Sch Forest Sci, Peatland & Soil Ecol Grp, Joensuu, Finland.
    Vellak, Kai
    Univ Tartu, Inst Ecol & Earth Sci, Tartu, Estonia.
    Verheyden, Anouk
    Union Coll, Dept Geol, Schenectady, NY USA.
    Waddington, James Michael
    McMaster Univ, Sch Geog & Earth Sci, Hamilton, Canada.
    Rice, Steven K.
    Union Coll, Dept Biol Sci, Schenectady, NY USA.
    Environmental and taxonomic controls of carbon and oxygen stable isotope composition in Sphagnum across broad climatic and geographic ranges2018In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 15, no 16, p. 5189-5202Article in journal (Refereed)
    Abstract [en]

    Rain-fed peatlands are dominated by peat mosses (Sphagnum sp.), which for their growth depend on nutrients, water and CO2 uptake from the atmosphere. As the isotopic composition of carbon (C-12(,)13) and oxygen (O-16(,)18) of these Sphagnum mosses are affected by environmental conditions, Sphagnum tissue accumulated in peat constitutes a potential long-term archive that can be used for climate reconstruction. However, there is inadequate understanding of how isotope values are influenced by environmental conditions, which restricts their current use as environmental and palaeoenvironmental indicators. Here we tested (i) to what extent C and O isotopic variation in living tissue of Sphagnum is speciesspecific and associated with local hydrological gradients, climatic gradients (evapotranspiration, temperature, precipitation) and elevation; (ii) whether the C isotopic signature can be a proxy for net primary productivity (NPP) of Sphagnum; and (iii) to what extent Sphagnum tissue delta O-18 tracks the delta O-18 isotope signature of precipitation. In total, we analysed 337 samples from 93 sites across North America and Eurasia us ing two important peat-forming Sphagnum species (S. magellanicum, S. fuscum) common to the Holarctic realm. There were differences in delta C-13 values between species. For S. magellanicum delta C-13 decreased with increasing height above the water table (HWT, R-2 = 17 %) and was positively correlated to productivity (R-2 = 7 %). Together these two variables explained 46 % of the between-site variation in delta C-13 values. For S. fuscum, productivity was the only significant predictor of delta C-13 but had low explanatory power (total R-2 = 6 %). For delta O-18 values, approximately 90 % of the variation was found between sites. Globally modelled annual delta O-18 values in precipitation explained 69 % of the between-site variation in tissue delta O-18. S. magellanicum showed lower delta O-18 enrichment than S. fuscum (-0.83 %0 lower). Elevation and climatic variables were weak predictors of tissue delta O-18 values after controlling for delta O-18 values of the precipitation. To summarize, our study provides evidence for (a) good predictability of tissue delta O-18 values from modelled annual delta O-18 values in precipitation, and (b) the possibility of relating tissue delta C-13 values to HWT and NPP, but this appears to be species-dependent. These results suggest that isotope composition can be used on a large scale for climatic reconstructions but that such models should be species-specific.

    Download full text (pdf)
    fulltext
  • 41.
    Granath, Gustaf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Strengbom, Joachim
    Swedish University of Agricultural Sciences.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Direct physiological effects of nitrogen on Sphagnum: a greenhouse experiment2012In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 26, no 2, p. 353-364Article in journal (Refereed)
    Abstract [en]

    1. Bogs are nutrient-poor peatland ecosystems that are sensitive to nitrogen (N) deposition. Production of peat mosses (i.e. the peat-forming genus Sphagnum) is known to decrease under elevated N deposition, but the causal mechanisms are poorly understood. 2. It is predicted that increased N deposition will cause changes in Sphagnum species composition, with fast-growing species benefiting from increased N availability in contrast to slow-growing species. Knowledge of species-specific responses to N availability can help us to understand interspecific competitive relationships. 3. We investigated the direct effects of N application on plant physiology in three Sphagnum species by exposing shoots to a range of N doses (corresponding to depositions of 0-5 6 g m) 2 year) 1), over 5 months, in a greenhouse experiment. The species investigated included one that grows high above the water-table (Sphagnum fuscum) and two that grow lower down (Sphagnum balticum and Sphagnum fallax). S. fuscum and S. balticum originate from ombrotrophic and S. fallax from minerotrophic environments. To estimate N responses, we measured the performance and light-capture kinetics of the photosynthetic apparatus (maximum photosynthetic rate and Fv/Fm), biomass production, shoot formation, and N and phosphorus (P) concentrations in the tissue. 4. Tissue nitrogen concentration generally increased with N application rate, and photosynthetic rate increased with N concentration, although S. balticum exhibited a unimodal response. With respect to production, a negative response to N application rate was found in S. fallax and S. fuscum (weak), while production in S. balticum was unrelated to application rate. S. fallax was the fastest-growing species, producing two to three times more biomass per shoot compared with the other species. 5. The mismatch between photosynthetic capacity and production could partly be explained by an increased N : P ratio following N application. Phosphorus limitation may not negatively affect photosynthetic capacity, but may hamper production. 6. The fast-growing species S. fallax is considered to benefit from increased N deposition, but we found a negative physiological response, suggesting stoichiometric constraints. Thus, we conclude that responses to N deposition cannot be predicted in a simple way from physiological traits related to growth rate without considering local environmental factors. 

  • 42.
    Granath, Gustaf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Strengbom, Joachim
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Rapid ecosystem shifts in peatlands: Linking plant physiology and succession2010In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 91, no 10, p. 3047-3056Article in journal (Refereed)
    Abstract [en]

    Stratigraphic records from peatlands suggest that the shift from a rich fen (calcareous fen) to an ombrotrophic bog can occur rapidly. This shift constitutes a switch from a species-rich ecosystem to a species-poor one with greater carbon storage. In this process, the invasion and expansion of acidifying bog species of Sphagnum (peat mosses) play a key role. To test under what conditions an acidifying bog species could invade a rich fen, we conducted three experiments, contrasting the bog species S. fucsum with the rich-fen species S. warnstorfii and S. teres. We first tested the effect of calcareous water by growing the three species at different constant height above the water table (HWT; 2, 7, and 14 cm) in a rich-fen pool and measured maximum photosynthetic rate and production and difference in length growth as an indicator of competition. In none of the species was the photosynthetic capacity negatively affected when placed at low HWT, but S. fuscum was a weaker competitor at low HWT. In our second experiment we transplanted the three species into microhabitats with different and naturally varying HWT in a rich fen. Here, S. fuscum nearly ceased to photosynthesize when transplanted to low HWT (brown moss carpet), while it performed similarly to the two rich-fen species at the intermediate level (S. warnstorfii hummock level). In contrast to S. fuscum, the rich-fen sphagna performed equally well in both habitats. The brown moss carpet was seasonally flooded, and in our third experiment we found that S. fuscum, but not S. teres, was severely damaged when submerged in rich-fen water. Our results suggest two thresholds in HWT affecting the ecosystem switch: one level that reduces the risk of submergence and a higher one that makes bog sphagna competitive against the rich-fen species.

  • 43.
    Granath, Gustaf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Strengbom, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Breeuwer, Angela
    Heijmans, Monique M. P. D.
    Berendse, Frank
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Photosynthetic performance in Sphagnum transplanted along a latitudinal nitrogen deposition gradient2009In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 159, no 4, p. 705-715Article in journal (Refereed)
    Abstract [en]

    Increased N deposition in Europe has affected mire ecosystems. However, knowledge on the physiological responses is poor. We measured photosynthetic responses to increasing N deposition in two peatmoss species (Sphagnum balticum and Sphagnum fuscum) from a 3-year, north-south transplant experiment in northern Europe, covering a latitudinal N deposition gradient ranging from 0.28 g N m(-2) year(-1) in the north, to 1.49 g N m(-2) year(-1) in the south. The maximum photosynthetic rate (NPmax) increased southwards, and was mainly explained by tissue N concentration, secondly by allocation of N to the   photosynthesis, and to a lesser degree by modified photosystem II activity (variable fluorescence/maximum fluorescence yield). Although climatic factors may have contributed, these results were most likely attributable to an increase in N deposition southwards. For S. fuscum, photosynthetic rate continued to increase up to a deposition level of 1.49 g N m(-2) year(-1), but for S. balticum it seemed to level out at 1.14 g N m(-2) year(-1). The results for S. balticum suggested that transplants from different origin (with low or intermediate N   deposition) respond differently to high N deposition. This indicates that Sphagnum species may be able to adapt or physiologically adjust to high N deposition. Our results also suggest that S. balticum might be more sensitive to N deposition than S. fuscum. Surprisingly, NPmax was not (S. balticum), or only weakly (S. fuscum) correlated with biomass production, indicating that production is to a great extent is governed by factors other than the photosynthetic capacity.

  • 44. Grandin, Ulf
    et al.
    Lönn, Mikael
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Allozyme variation at a PGI locus in differently aged populations of Moehringia trinervia (Caryophyllaceae) in a successional area2002In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 22, no 3, p. 303-311Article in journal (Refereed)
    Abstract [en]

    We studied genetic effects of the colonisation process during primary succession by analysing allozyme variation at a PGI locus in differently aged populations of Moehringia trinervia, which is a selfing annual with low dispersal ability. The populations studied come from islands and shores created in the 1880s by a drop in the water table of a Swedish lake and from old parts of a large island and of the mainland. The population age is known from five vegetation analyses over a century. We have also analysed the genetic composition of M. trinervia derived from seeds in the soil. Mainland populations had a higher genetic diversity than island populations that were little differentiated and differed genetically from the mainland populations. There was no temporal trend in the distribution of genetic variation on the new islands. The presence of alleles in the extant populations was associated with the proportion of that allele in the seed bank, indicating a main recruitment from the seed bank and not by repeated immigrations. We suggest that some of the new islands were colonised by a few early founders from the mainland. Later colonisation has occurred between adjacent islands, which preserves the founder effect and could explain the uniform, low genetic variation in the island populations.

  • 45.
    Grandin, Ulf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecological Botany.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecological Botany.
    Attributes of the seed bank after a century of primary succession on islands in Lake Hjalmaren, Sweden1998In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 86, no 2, p. 293-303Article in journal (Refereed)
    Abstract [en]

    1  A large number of islands was created when the water table of Lake Hjälmaren, south central Sweden, was lowered between 1882 and 1886. We have complete lists of vascular plant species for 40 of these islands from 1886, 1892, 1903–04, 1927–28 and 1984–85.

    2   We have investigated the seed bank on nine of these islands and compared species composition at different soil depths with the species lists from the islands in 1886–1985, and with the present vegetation in the area of seed bank sampling. We have also investigated the distribution in the soil of seeds from species with different ecological attributes, including seed longevity, successional status, seed weight, seed form and species longevity.

    3  Seeds in soil samples were allowed to germinate over the course of two summers with an intermediate cold storage. We found 1944 seeds representing 65 taxa. The mean seed density was 84 seeds dm–2.

    4   The similarity between the surface soil (0–3 cm) seed bank and the vegetation at the different vegetation analyses increased from 1886 to 1993. The similarity between the present vegetation and the seed bank decreased with increasing soil depth, and the soil at 12–15 cm had no species in common with the present vegetation. Several species now absent from the vegetation were found in the seed bank.

    5   Deeply buried seeds came from early successional, annual species with long-term persistent and low-weight seeds, as expected from seed bank theories, but were slightly elongated, which was in contrast to theories. Spherical seeds were associated with the surface soil, as were short-lived and high-weight seeds from late successional, perennial species.

  • 46.
    Gunnarsson, U
    et al.
    Uppsala University.
    Rydin, H
    Uppsala University.
    Demography and recruitment of Scots pine on raised bogs in eastern Sweden and relationships to microhabitat differentiation1998In: Wetlands (Wilmington, N.C.), ISSN 0277-5212, E-ISSN 1943-6246, WETLANDS, ISSN 0277-5212, Vol. 18, no 1, p. 133-141Article in journal (Other academic)
    Abstract [en]

    Scots pines (Pinus sylvestris) growing on open bogs occur preferentially on hummocks and on the margin of the bogs. To assess which life history stages lead to this uneven distribution, we studied how variation in the ground-water level influences recruit

  • 47.
    Gunnarsson, Urban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Boresjö Bronge, L
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ohlson, M
    Near-zero recent carbon accumulation in a bog with high nitrogen deposition in SW Sweden2008In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 14, p. 2152-2165Article in journal (Refereed)
    Abstract [en]

    We present data on the accumulation of carbon and nitrogen into an open oceanic ombrotrophic bog, SW Sweden, with high levels of anthropogenic nitrogen deposition. The aim was to investigate if this peatland currently acts as a sink for atmospheric carbon. Peat cores were sampled from the top peat layer in five different vegetation types. Small pines were used to date the cores. The cores bulk density and carbon and nitrogen content were determined. A vegetation-classified satellite image was used to estimate the areal extent of the vegetation types and to scale up these results to bog level. The rate of current carbon input into the upper oxic acrotelm was 290 g m(-2) yr(-1), and there were no significant differences in accumulation rates among the vegetation types. This organic matter input to the acrotelm was almost completely decomposed before it was deposited for storage in the deeper peat layers (the catotelm) and only a small fraction (< , 1%) or 0.012 g m(-2) yr(-1) of the carbon would be left, assuming a residence time of 100 years in the acrotelm. Nitrogen accumulation rates differed between the vegetation classes, and the average input via primary production varied from 5.33 to 16.8 g m(-2) yr(-1). Current nitrogen input rates into the catotelm are much lower, 0-0.059 g m(-2) yr(-1), with the highest accumulation rates in lawn-dominated communities. We suggest that one of the main causes of the low carbon input rates is the high level of nitrogen deposition, which enhances decomposition and changes the vegetation from peat-forming Sphagnum-dominance to dominance by dwarf shrubs and graminoids.

  • 48.
    Gunnarsson, Urban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Malmer, N.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Dynamics or constancy in Sphagnum dominated mire ecosystems? A 40-year study2002In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 25, no 6, p. 685-704Article in journal (Refereed)
    Abstract [en]

    Traditionally mire ecosystems (especially bogs) have been viewed as stable systems with slow changes in the vegetation over time. In this study the mire Akhultmyren, south-central Swedenw as re-investigatedin 1997 after 40 yr of continued natural development. The results show a high degree of dynamics in a Sphagnum dominated bog and fen. Altogether 97 vascular plant and bryophyte species were recorded in the two inventories of the bog and poor fen vegetation ,p H and electrical conductivity in the mire water were also surveyed. In 1997 we found 10 new species and that 8 species had disappeared since 1954 but the over-all mean number of species per plot (size 400 m2) had hardly changed. However, 21% of the species increased and 21% decreased significantly in frequency. Most of the species that decreased in frequency were low-grown vascular plants, most common in wet microhabitats. Vascular plant species that increased in frequency included trees (defined as > 1.3 m in height) and were generally taller than the unchanged or decreasing species. The frequency of dwarf shrubs and hummock bryophytes increased too. Areas with an initial pH of 4.5-5.0 showed the strongest decrease in pH, coinciding with an enlarged distribution of some Sphagnum species. The species diversity increased on the bog, but decreased in the wettest parts of the fen, where the pH also decreased. Species with unchanged or increasing frequency often showed high capacity to colonise new plots. On average the sum of gains and losses of species in the plots in 1997 was ca 50% of the species number in 1954. The vegetation changes indicate a drier mire surface and anincreaseda vailability of nitrogen. The increased tree cover may have triggered further changes in the plant cover.

  • 49.
    Gunnarsson, Urban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Nitrogen fertilization reduces Sphagnum production in bog communities2000In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 147, no 3, p. 527-537Article in journal (Refereed)
    Abstract [en]

    The effects of increased nitrogen influx on Sphagnum growth and on interspecific competition between Sphagnum species were studied in a 3-yr experiment in mires situated in two areas with different rates of airborne N deposition. Sphagnum growth was recorded after various supplementary N influxes (0, 1, 3, 5 and 10 g m −2 yr−1) in hummocks and lawn communities. Sphagnum biomass production decreased with increasing N influx in both areas. After the first season at the low-deposition site, Sphagnum showed an increased growth in length with the intermediate N treatment, but in the second and third seasons the control treatment had the highest growth in length. Capitulum dry mass increased with increasing N influx. Sphagnum N concentration and N/P quotient were higher at the high- than at the low-deposition site. The low quotient at the low-deposition site, together with the initial growth increase with intermediate N supplements, indicates that growth was N-limited at this site, but our lowest N supplement was sufficient to reduce growth. The N treatments had no effect on interspecific competition between the Sphagnum species. This indicates that the species have similar responses to N. The species studied all occur naturally on ombrotrophic, N-poor sites and show low tolerances to increased N influx. Reduced Sphagnum production may affect the carbon balance, changing the mires from C sinks to sources.

  • 50.
    Gunnarsson, Urban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Sjörs, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Diversity and pH changes after 50 years on the boreal mire Skattlosbergs Stormosse, Central Sweden2000In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 11, no 2, p. 277-286Article in journal (Refereed)
    Abstract [en]

    The Skattlosbergs Stormosse min was reinvestigated in 1995 after 50 years of natural development since the previous investigation. The undrained mire is situated in an area with low anthropogenic deposition. The distribution of 106 plant species was mapped in detail and pH was measured at 251 locations, providinga unique opportunity to quantify long-term mire dynamics. The resultss how decreased pH in the richer (high-pH) parts of the mire, but little or no change in the poor fen andombrotrophipca rts.1 4 species had disappeared while two news pecies were recorded. Most species had a more restricted distribution in the mire area in 1995 than in 1945. Species richness in lOm x 0Omp lots had decreased, especially in plots with higher pH. Most Sphagnum species had unchanged distributions over the mire, while 7 3 % of other bryophyt sepecies and 3 8% of vascular plant species had decreased by more than 20 % in plot frequency. There was a strong relationship between number of species and pH-value. The mean and standard eviation of pH in plots where the species occurred have both decreased since 1945. We interpret the changes in species richness in the richer fens to be mainly caused by acidification. This could partly be an autogenic succession, but may be enhanced by increased atmospheric deposition. The mire represents an almost untouched site which can act as a reference for mires in morepolluted areas.

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