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  • 1. Aarrestad, P. A.
    et al.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Masunga, G.
    Skarpe, C.
    Vegetation: Between Soils and Herbivores2014In: Elephants and Savanna Woodland Ecosystems: A Study from Chobe National Park, Botswana / [ed] Christina Skarpe, Johan T. du Toit and Stein R. Moe, Wiley-Blackwell, 2014, p. 61-88Chapter in book (Refereed)
    Abstract [en]

    The vegetation of the study area in Chobe National Park is influenced by a range of factors, including inundation by the Chobe River, soil moisture and fertility, and the impacts of different-size grazers and browsers. This chapter focuses on how the structure and species composition of the present vegetation in northern Chobe National Park is related to recent herbivory by elephants, as agents shaping the vegetation, and by mesoherbivores acting as controllers or responders, along with abiotic controllers such as soil type and distance to the river. In the study, a two-way indicator species analysis classified the vegetation data into four more or less distinct plant community groups (i) Baikiaea plurijuga-Combretum apiculatum woodland, (ii) Combretum mossambicense-Friesodielsia obovata wooded shrubland, (iii) Capparis tomentosa-Flueggea virosa shrubland and (iv) Cynodon dactylon-Heliotropium ovalifolium floodplain, named after the TWINSPAN indicator or preferential species with high cover, and the relative amount of shrubs and trees.

  • 2. Aarrestad, P. A.
    et al.
    Masunga, G. S.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Pitlagano, M. L.
    Marokane, W.
    Skarpe, C.
    Influence of soil, tree cover and large herbivores on field layer vegetation along a savanna landscape gradient in northern Botswana2011In: Journal of Arid Environments, ISSN 0140-1963, E-ISSN 1095-922X, Vol. 75, no 3, p. 290-297Article in journal (Refereed)
    Abstract [en]

    The response of the field layer vegetation to co-varying resource availability (soil nutrients, light) and resource loss (herbivory pressure) was investigated along a landscape gradient highly influenced by elephants and smaller ungulates at the Chobe River front in Botswana. TWINSPAN classification was used to identify plant communities. Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) were used to explore the vegetation-environment relationships. Four plant communities were described: Panicum maximum woodland, Tribulus terrestris woodland/shrubland, Chloris virgata shrubland and Cynodon dactylon floodplain. Plant height, species richness and diversity decreased with increasing resource availability and resource loss. The species composition was mainly explained by differences in soil resources, followed by variables related to light availability (woody cover) and herbivory, and by interactions between these variables. The vegetation structure and species richness, on the other hand, followed the general theories of vegetation responses to herbivory more closely than resource related theories. The results suggest a strong interaction between resource availability and herbivory in their influence on the composition, species richness and structure of the plant communities.

  • 3.
    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.
    "Det har vi vetat hela tiden!": akademikerna och lövängen för hundra år sedan2019In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 113, no 3/4, p. 219-231Article in journal (Refereed)
    Abstract [en]

    Mown meadows with scattered trees were a characteristic of the old Swedish landscape.  It has been an established truth that the botanists, particularly R. Sernander and H. Hesselman, did not understand that the meadows would turn into forests when abandoned, whereas the human geographer M. Sjöbeck in several publications from 1927 onwards made this clear. This view was supported by, i.a,. L.-G. Romell.

     We have scrutinized the literature and the minutes of the Plant Biology Seminar in Uppsala from 1892 to 1944, in order to understand Sernander’s views. Hesselman considered the matter uncertain. Sernander probably understood the dynamics also before 1927, but his standpoint was influenced by a wish to restore the postglacial broadleaved forests of which he saw the meadows as degraded relicts. This could be done by leaving meadows for free development. Gradually he saw the need also to maintain meadows and the cultural landscape as such. Several other botanists, e.g. G. Samuelsson and G. Einar Du Rietz, already early on understood the dependence of meadows on human management. 

  • 4.
    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.

  • 5.
    Backéus, Ingvar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Skoglund, Jerry
    Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Skarpe, Christina
    Campus Evenstad, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Inland Norway University of Applied Sciences, Elverum, Norway.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Diameter growth of trees in miombo and acacia woodland in an eroded landscape in NE Tanzania2022In: African Journal of Ecology, ISSN 0141-6707, E-ISSN 1365-2028, Vol. 60, no 3, p. 714-722Article in journal (Refereed)
    Abstract [en]

    Diameter increment of trees typical of miombo and acacia woodland was studied dur- ing a period of 20 years in Kondoa district, Tanzania. The study was performed in permanent plots in a severely degraded area subjected to considerable restoration efforts. A total of 15 species were selected from a database collected within a pro- ject for monitoring the landscape recovery. Growth performance of African woodland species was searched for in the literature for comparison, and a comprehensive list of citations was compiled. We found growth to fall within the range reported in earlier studies, although growth varied both between and within species. There are reports that the radial increments of trees are unimodal over their lifespan, but we found no clear support. In several species, the annual growth increased with stem diameter. Growth during the rainy ENSO year 1997/98 was pairwise compared with the preced- ing two years and was found to be significantly higher during the wet year, pointing to soil water as a limiting factor. We conclude that free development is an alternative to tree planting on marginal land.

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  • 6.
    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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  • 7. Hilmo, Olga
    et al.
    Ely-Aastrup, Hilde
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Holien, Håkon
    Population characteristics of old forest associated epiphytic lichens in Picea abies plantations in the boreal rainforest of Central Norway2011In: Canadian Journal of Forest Research, ISSN 0045-5067, E-ISSN 1208-6037, Vol. 41, no 9, p. 1743-1753Article in journal (Refereed)
    Abstract [en]

    The boreal rainforest in Central Norway is rich in rare and (or) red-listed epiphytic lichens but is subject to forest harvesting. Natural old Picea abies (L.) H. Karst. forests have been replaced increasingly by dense, even-aged plantations. This study aims at increasing our knowledge about populations of old forest associated lichens in P. abies plantations. In differently aged plantations, we measured occurrence of six lichen species and the population size and reproductive effort of :five lichen species. We found that the success of colonizing plantations differed because of species-specific constraints and needs, and that species occurrence depended on stand age and branch quality. A high number of reproducing thalli and small juvenile thalli of the cyanolichen Lobaria scrobiculata (Scop.) DC. and the pendulous lichen Ramalina thrausta (Ach.) Nyl. suggest effective recruitment within plantations. The populations of the cyanolichens Lobaria pulmonaria (L.) Hoffm. and Pseudocphellaria crocata (L.) Vain, were too small to be viable and demand special concern to survive in managed forests. The abundance of old forest associated lichens in a managed boreal rainforest could be promoted by a varied and heterogeneous branch structure, increased rotation periods (increase the value of plantations as propagule sources), small clearcuts and retention trees (shorten the distance between sources of propagules and target substrate), and maintaining Salix and Sorbus trees (important host trees for cyanolichens and thereby important dispersal sources).

  • 8. HILMO, Olga
    et al.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    HOLIEN, Håkon
    Do different logging strategies influence the abundance of epiphytic chlorolichens?2005In: The Lichenologist, ISSN 0024-2829, E-ISSN 1096-1135, Vol. 37, no 6, p. 543-553Article in journal (Refereed)
  • 9.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Deciduous woodland at Andersby, eastern Sweden: above-ground tree and shrub production1975Doctoral thesis, monograph (Other academic)
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  • 10.
    Hytteborn, Håkan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Carlsson, Bengt Å.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Svensson, Brita M.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Zhang, Liquan
    State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China .
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Spatial heterogeneity ensures long-term stability in vegetation and Fritillaria meleagris flowering in Uppsala Kungsäng, a semi-natural meadow2023In: PLOS ONE, E-ISSN 1932-6203, Vol. 18, no 3, article id e0282116Article in journal (Refereed)
    Abstract [en]

    Semi-natural grasslands are becoming increasingly rare, and their vegetation may be affected by environmental changes and altered management. At Kungsängen Nature Reserve, a wet to mesic semi-natural meadow near Uppsala, Sweden, we analysed long-term changes in the vegetation using data from 1940, 1982, 1995 and 2016. We also analysed the spatial and temporal dynamics in the Fritillaria meleagris population based on countings of flowering individuals in 1938, 1981–1988 and 2016–2021. Between 1940 and 1982 the wet part of the meadow became wetter, which led to an increased cover of Carex acuta and pushed the main area of flowering of F. meleagris up towards the mesic part. Annual variation in the flowering propensity of F. meleagris (in May) was affected by temperature and precipitation in the phenological phases of growth and bud initiation (June in the previous year), shoot development (September in the previous year) and initiation of flowering (March–April). However, the response to weather was in opposite directions in the wet and mesic parts of the meadow, and the flowering population showed large year-to-year variation but no long-term trend. Variation in management (poorly documented) led to changes in different parts of the meadow, but the overall composition of the vegetation, species richness and diversity changed little after 1982. Species richness and species composition of the meadow vegetation, and the long-term stability of the F. meleagris population are maintained by the variation in wetness, highlighting the importance of spatial heterogeneity as an insurance against biodiversity loss in semi-natural grasslands and nature reserves generally.

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  • 11.
    Hytteborn, Håkan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Packham, John R.
    Verwijst, Theo
    Tree population dynamics, stand structure and species composition in the montane virgin forest of Vallibäcken, northern Sweden1987In: Plant Ecology, ISSN 1385-0237, E-ISSN 1573-5052, Vol. 72, no 1, p. 3-19Article in journal (Refereed)
  • 12.
    Hytteborn, Håkan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Svensson, Brita M.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Kempe, Kerstin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Press, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Century-long tree population dynamics in a deciduous forest stand in central Sweden2017In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 28, no 5, p. 1057-1069Article in journal (Refereed)
    Abstract [en]

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

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

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

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

  • 13.
    Hytteborn, Håkan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Verwijst, Theo
    Small-scale disturbance and stand structure dynamics in an old-growth Picea abies forest over 54 yr in central Sweden2014In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 25, no 1, p. 100-112Article in journal (Refereed)
    Abstract [en]

    QuestionsCan assumptions of the existence of spatially distinct patches (delineated structurally homogeneous parts of the forest, being either areas consisting of canopy trees or areas without canopy trees but in an early or later regenerative phase) and of directional development over time of the vegetation in such patches, as implied by current theory of storm gap dynamics, be verified by remapping previous study sites? LocationNatural, unmanaged boreo-nemoral spruce-dominated forest in eastern central Sweden. MethodsBy re-mapping three plots, ca, 50yr after the first inventory, we studied the structure and dynamics of gaps (patches without canopy tree cover) and major tree populations. The old and new maps allowed us to compare two independent assessments of the forest dynamics: one based on tree population changes and one on changes in gap area over time. ResultsThe current population structure could partly be described through the earlier-encountered structures of the different tree populations and consecutive processes of recruitment and mortality. However, the re-mapping exercise showed that spatially delineated patches did not develop directionally over time, nor was their development spatially discrete. ConclusionsPatch dynamics proceeds in such a way that the fate of a single patch may depend on the development of neighbouring patches. As gaps may partly close or merge into larger gaps, and as gap disappearance rate is a function of actual gap size, performance of an initially delimited patch is largely determined by developments in neighbouring patches and cannot be predicted from its momentary patch characteristics. Consequently, we propose an open matrix model' to describe the changes in a boreo-nemoral spruce forest, rather than a storm gap dynamics' model.

  • 14.
    Hytteborn, Håkan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Verwijst, Theo
    Stand structure and regeneration in a montane virgin forest along an altitudinal gradient on the Vallevare mountain, northwern Sweden.1989In: Forests of the World - diversity and dynamics / [ed] E. Sjögren, Uppsala: Svenska Växtgeografiska Sällskapet , 1989, p. 127-130Chapter in book (Refereed)
  • 15.
    Kaarlejärvi, Elina
    et al.
    Department of Ecology and Environmental Sciences, Umeå University.
    Baxter, Robert
    School of Biological and Biomedical Sciences, University of Durham.
    Hofgaard, Annika
    Norwegian Institute for Nature Research,Trondheim.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Khitun, Olga
    Department of Biological and Environmental Sciences, University of Gothenburg.
    Molau, Ulf
    Department of Biological and Environmental Sciences, University of Gothenburg.
    Sjögersten, Sofie
    School of Biosciences, University of Nottingham.
    Wookey, Philip
    Department of Geography, University of Sheffield.
    Olofsson, Johan
    Department of Ecology and Environmental Sciences, Umeå University.
    Effects of warming on shrub abundance and chemistry drive ecosystem-level changes in a forest-tundra ecotone2012In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 15, no 8, p. 1219-1233Article in journal (Refereed)
    Abstract [en]

    Tundra vegetation is responding rapidly to on-going climate warming. The changes in plant abundance and chemistry might have cascading effects on tundra food webs, but an integrated understanding of how the responses vary between habitats and across environmental gradients is lacking. We assessed responses in plant abundance and plant chemistry to warmer climate, both at species and community levels, in two different habitats. We used a long-term and multisite warming (OTC) experiment in the Scandinavian forest–tundra ecotone to investigate (i) changes in plant community composition and (ii) responses in foliar nitrogen, phosphorus, and carbon-based secondary compound concentrations in two dominant evergreen dwarf-shrubs (Empetrum hermaphroditum and Vaccinium vitis-idaea) and two deciduous shrubs (Vaccinium myrtillus and Betula nana). We found that initial plant community composition, and the functional traits of these plants, will determine the responsiveness of the community composition, and thus community traits, to experimental warming. Although changes in plant chemistry within species were minor, alterations in plant community composition drive changes in community-level nutrient concentrations. In view of projected climate change, our results suggest that plant abundance will increase in the future, but nutrient concentrations in the tundra field layer vegetation will decrease. These effects are large enough to have knock-on consequences for major ecosystem processes like herbivory and nutrient cycling. The reduced food quality could lead to weaker trophic cascades and weaker top down control of plant community biomass and composition in the future. However, the opposite effects in forest indicate that these changes might be obscured by advancing treeline forests.

  • 16.
    Lokken, Jorn Olav
    et al.
    Norwegian Inst Nat Res, POB 5685, NO-7485 Trondheim, Norway;Norwegian Univ Sci & Technol, Dept Biol, Trondheim, Norway.
    Hofgaard, Annika
    Norwegian Inst Nat Res, POB 5685, NO-7485 Trondheim, Norway.
    Dalen, Linda
    Norwegian Environm Agcy, Trondheim, Norway.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Grazing and warming effects on shrub growth and plant species composition in subalpine dry tundra: An experimental approach2019In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 30, no 4, p. 698-708Article in journal (Refereed)
    Abstract [en]

    Questions

    Vegetation in the forest–tundra ecotone faces changes in both climate and land‐use. While climate warming is an important driver of vegetation growth and composition, herbivory may have opposing effects. In the present study, we experimentally test how removal of sheep herbivory affects the vegetation in an alpine forest–tundra ecotone, and how responses are manifested at higher temperatures.

    Location

    Dovre Mountains, Central Norway.

    Methods

    Shrub growth (height and cover) and ground layer composition were analysed each third year over an 18‐year period in a nested, three‐factorial experiment (ambient temperature and herbivory; ambient temperature and no herbivory; increased temperature and no herbivory). Fencing and open‐top‐chambers were used as expedients. Treatment effects and interactions over time were analysed using linear mixed effects models and ordination.

    Results

    Shrub height and cover increased over time due to reduced herbivory, but without additional warming effect. Lichen cover declined in all treatments over time, but more rapidly and earlier under warming treatment (significant after three years). Contrary to expectations, there was no statistically significant increase in woody species due to warming, although evergreen woody species displayed a trend shift after six years, comprising a sharp decline towards year twelve. Litter accumulated in all treatments, but at higher rates under warming (significant after nine years).

    Conclusions

    Our results disclose removal of sheep herbivory as a prominent driver of shrub growth, with warming as a subordinate driver in the studied alpine vegetation. The warming‐driven increased litter abundance may, however, be caused by the decrease of wind inside chambers and the subsequent absence of wind‐driven removal of litter. This chamber effect and the displayed timing differences in vegetation responses call for the critical use of short‐term experimental data in predictions of long‐term consequences of environmental change.

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  • 17. Moe, S. R.
    et al.
    Rutina, L.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Du Toit, J. T.
    Impala as Controllers of Elephant-Driven Change within a Savanna Ecosystem2014In: Elephants and Savanna Woodland Ecosystems: A Study from Chobe National Park, Botswana / [ed] Christina Skarpe, Johan T. du Toit and Stein R. Moe, Wiley-Blackwell, 2014, p. 154-171Chapter in book (Refereed)
    Abstract [en]

    To understand ecosystem structure and dynamics we need more knowledge of how common species affect ecosystem dynamics. In this context, impala are especially interesting in the Chobe ecosystem, where they are now common but were much less so just a few decades ago. The chapter uses the Chobe ecosystem as a case-study to explore the possibility that the recovery of the elephant population has created habitat that favours impala. The authors hypothesise that, following changes in plant structure and species composition along the Chobe river caused by increasing numbers of elephant, the impala population grew substantially and is currently preventing the shrubland from reverting to its previous woodland state. The conceptual framework used in the chapter is that of Pickett et al., in which elephants function as agents responsible for the change in state. Species other than impala can also play a role in seedling predation in African Savannas.

  • 18.
    Pedrotti, E.
    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.
    Ingmar, T.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Turunen, P.
    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.
    Fine-scale dynamics and community stability in boreal peatlands: revisiting a fen and a bog in Sweden after 50 years2014In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 5, no 10, p. 133-Article in journal (Refereed)
    Abstract [en]

    Multi-decadal studies of community and ecosystemdynamics are rare; however, this time frame is most relevant for assessing the impact of anthropogenic influences and climate change on ecosystems. For this reason, we investigated changes in vegetation and microtopography over 52 years in two contrasting mire ecosystems, one ombrotrophic (bog) and one minerotrophic (fen), representing different successional stages and contrasting hydrological settings. In both peatlands, floristic composition was recorded in the same permanent plots (n = 55-56, 0.25 m(2)) in both 1960 and 2012 and microtopography was mapped over a large area (ca. 2500 m(2)) that encompassed these same plots. We quantified and compared the community-level changes and internal spatial dynamics, tested associations between pH/microtopography and community/species change, and examined how the area and location of hummock microforms had changed over time. The bog exhibited little site level change in vegetation, where few species changed significantly in cover and plot frequency. However, detailed analyses revealed some large within-plot changes over time in the bog, illustrating that bogs can be highly dynamic systems at a fine scale. In contrast, the rich fen experienced a clear directional change; specifically, bryophyte abundance decreased by 70% and brown mosses were almost extinct. Although pH had decreased over time at the rich fen, this decrease at the plot-level was not associated with the decline of brown moss abundance. The microtopographic structure did not change substantially at the bog where similar to 70% was covered by lawn/hummocks; however, in the rich fen hummocks expanded (from 10% to 16% cover) and moved or expanded down slope. Our study suggests, that at the site-level, the bog ecosystem was more resistant to environmental changes over time compared to the rich fen, as evidenced by shifts in vegetation and microtopography. The contrasting scales of vegetation dynamics observed within a bog (i.e., within-plot changes vs. site-level) indicate that plant-environment feedbacks contribute to the peatland level stability. While in rich fens, internal feedbacks may be weaker and the ecosystem's vegetation and microtopographic structure are vulnerable to shifting hydrological fluxes.

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  • 19. Skarpe, C.
    et al.
    Bergström, R.
    Makhabu, S.
    Rooke, T.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Danell, K.
    Plant-Herbivore Interactions2014In: Elephants and Savanna Woodland Ecosystems: A Study from Chobe National Park, Botswana / [ed] C. Skarpe, J. T. du Toit and S. R. Moe, Wiley-Blackwell, 2014, p. 189-206Chapter in book (Refereed)
    Abstract [en]

    To a casual observer, the importance of large herbivores for ecosystem structure and dynamics can seem more obvious in African savannas than in many other ecosystems because of their high abundance, diversity and species richness of ungulates. African savannas have also had a long uninterrupted history of mammalian herbivory, leading to the evolution of plant traits adapted to herbivory and to reciprocal traits in herbivores. In nutrient-poor savannas such as those on Kalahari sand in the Chobe National Park, Botswana, elephants, Loxodonta africana, are a main agent creating spatial and temporal variation in the vegetation and ecosystems. Within this framework, elephants and smaller herbivores interact with individual plants and plant populations, exploiting and modifying heterogeneity at many scales. Intermittent grazing in systems of migratory or highly mobile herbivores provides food plants with a recovery period, and could be one reason for the 'success' and abundance of many migratory herbivore species.

  • 20. Skarpe, C.
    et al.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Moe, S. R.
    Aarrestad, P. A.
    Historical Changes of Vegetation in the Chobe Area2014In: Elephants and Savanna Woodland Ecosystems: A Study from Chobe National Park, Botswana / [ed] Christina Skarpe, Johan T. du Toit and Stein R. Moe, Wiley-Blackwell, 2014, p. 43-60Chapter in book (Refereed)
    Abstract [en]

    Elephants are the main agent shaping the vegetation (substrate), whereas soil properties and, at a larger scale, climate constitute major controllers of elephants' activities and of their effects on vegetation. However, elephants have not been the only agents of change in the Chobe ecosystem and its vegetation during the 150 or more turbulent years covered by this chapter. There have been others. The chapter discusses the vegetation dynamics that took place concurrently with the fall and rise of the elephant population following the ivory hunt in the end of the 20th century, and explains the relative importance of elephants, smaller herbivores and direct human impact through logging, burning and livestock grazing in causing these changes. The fall and rise of the Chobe elephant population during the last 150 or so years, has affected the vegetation on the relatively nutrient rich alluvium differently from that on the nutrient-deficient sand.

  • 21. Skarpe, Christina
    et al.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Cramer, Wolfgang
    Femtio års skogsutveckling på Granskär, norra Uppland1989In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 83, p. 177-185Article in journal (Refereed)
  • 22.
    Skoglund, Jerry
    et al.
    Swedish Univ Agr Sci, Box 7044, SE-75007 Uppsala, Sweden;Boksta 308, S-74495 Vittinge, Sweden.
    Karlsson, Sven
    Stockholm Univ, Dept Phys Geog, SE-10691 Stockholm, Sweden.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Vegetation history of the primeval forest Fiby urskog, south Sweden2020In: Review of Palaeobotany and Palynology, ISSN 0034-6667, E-ISSN 1879-0615, Vol. 274, article id 104151Article in journal (Refereed)
    Abstract [en]

    Vegetation history of a primeval forest (Fiby urskog) in south Sweden is outlined from a paleoecological perspective. Pollen, spores, charcoal fragments and mineral particles were analyzed from a small, centrally placed wetland basin. C-14 dating, diatom analysis and shore displacement data aided in dating the vegetation succession. Indicators of human impact and other disturbances, during the last ca 1000 years, are given particular attention, as well as Picea immigration. Elevated parts of Fiby area rose above the Littorina Sea level ca 7000 BP. Early establishing forest included Pinus, Betula, Alnus and Quercetum mixtum forest species. The wetland basin became isolated ca 5800 cal. yr BP. Drier conditions eventually permitted woody species such as Alnus and Betula to enter the basin from ca 4540 cal. yr BP, or earlier. Sedimentation stopped in the contemporary warm and dry conditions creating an hiatus. Paludification occurred and sedimentation resumed from ca 2600 cal. yr BP, turning the basin into Sphagnum fen with Menyanthes trifoliata, Lysimachia and Carex spp. Pinus and Betula maintained strong presence though some species, particularly Alnus, continued a decreasing trend. Fires were mainly restricted to bedrock outcrops. Last extensive fires were at ca 600 and 400 cal. yr BP. A much delayed Picea immigration commenced from ca 300 cal. yr BP, accompanied by a decline in forest fires. Occasional cereal and weed pollen indicating agricultural activity appear, but are considered as imports from surrounding landscapes. Gap phase dynamics evolve as the most important disturbance factor in the final Picea dominated forest. 

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