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  • 201.
    Stenøien, Hans K
    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.
    Adaptive basis of codon usage in the haploid moss Physcomitrella patens2005In: Heredity, Vol. 94, p. 87-93Article in journal (Refereed)
  • 202.
    Stenøien, Hans K
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Bryophyte species and population concepts in relation to molecular markers2002In: Lindbergia, Vol. 27, p. 115-121Article in journal (Refereed)
  • 203.
    Stenøien, Hans K
    et al.
    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.
    Fenster, CB
    Tonteri, A
    Savolainen, O
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Plant Ecology.
    Genetic variability in natural populations of Arabidopsis thaliana from northern Europe2005In: Molecular Ecology, Vol. 14, p. 137-148Article in journal (Refereed)
  • 204.
    Stenøien, Hans K
    et al.
    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.
    Pedersen, B
    Mutation and epimutation load in haploid and diploid life forms2005In: Journal of Theoretical Biology, Vol. 233, p. 119-126Article in journal (Refereed)
  • 205.
    Stenøien, Hans K
    et al.
    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.
    Stephan, W
    Global mRNA stability is not associated with levels of gene expression in Drosophila melanogaster but shows a negative correlation with codon bias2005In: Journal of Molecular Evolution, Vol. 61, p. 306-314Article in journal (Refereed)
  • 206.
    Strengbom, Joachim
    et al.
    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.
    Englund, G
    Ericson, L
    Experimental scale and precipitation modify effects of nitrogen addition on a plant pathogen2006In: Journal of Ecology, Vol. 94, p. 227-233Article in journal (Refereed)
  • 207.
    Strengbom, Joachim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Reich, P.B.
    Elevated [CO2] and increased N supply reduce leaf disease and related photosynthetic impacts on Solidago rigida2006In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 149, no 3, p. 519-525Article in journal (Refereed)
    Abstract [en]

    To evaluate whether leaf spot disease and related effects on photosynthesis are influenced by increased nitrogen (N) input and elevated atmospheric CO2 concentration ([CO2]), we examined disease incidence and photosynthetic rate of Solidago rigida grown in monoculture under ambient or elevated (560 mu mol mol(-1)) [CO2] and ambient or elevated (+4 g N m(-2) year(-1)) N conditions in a field experiment in Minnesota, USA. Disease incidence was lower in plots with either elevated [CO2] or enriched N (-57 and -37%, respectively) than in plots with ambient conditions. Elevated [CO2] had no significant effect on total plant biomass, or on photosynthetic rate, but reduced tissue%N by 13%. In contrast, N fertilization increased both biomass and total plant N by 70%, and as a consequence tissue%N was unaffected and photosynthetic rate was lower on N fertilized plants than on unfertilized plants. Regardless of treatment, photosynthetic rate was reduced on leaves with disease symptoms. On average across all treatments, asymptomatic leaf tissue on diseased leaves had 53% lower photosynthetic rate than non-diseased leaves, indicating that the negative effect from the disease extended beyond the visual lesion area. Our results show that, in this instance, indirect effects from elevated [CO2], i.e., lower disease incidence, had a stronger effect on realized photosynthetic rate than the direct effect of higher [CO2].

  • 208.
    Strengbom, Joachim
    et al.
    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.
    Witzell, J
    Nordin, A
    Ericson, L
    Do multitrophic interactions override N fertilization effects on Operophtera larvae?2005In: Oecologia, Vol. 143, p. 241-250Article in journal (Refereed)
  • 209.
    Strömquist, Lennart
    et al.
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Social and Economic Geography.
    Backéus, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Integrated landscape analyses of change of miombo woodland in Tanzania and its implication for environment and human livelihood2009In: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 91A, no 1, p. 31-45Article in journal (Refereed)
    Abstract [en]

    Landscapes bear witness to past and present natural and societal processes influencing the environment and human livelihoods. By analysing landscape change at different spatial scales over time the effects on the environment and human livelihoods of various external and internal driving forces of change can be studied. This paper presents such an analysis of miombo woodland surrounding the Mkata plains in central Tanzania. The rich natural landscape diversity of the study area in combination with its historical and political development makes it an ideal observation ground for this kind of study. The paper focuses on long-term physical and biological changes, mainly based on satellite information but also on field studies and a review of documents and literature.

    The miombo woodlands are highly dynamic semi-arid ecosystems found on a number of nutrient-poor soil groups. Most of the woodlands are related to an old, low-relief geomorphology of erosion surfaces with relatively deep and leached soils, or to a lesser extent also on escarpments and steep Inselberg slopes with poor soils. Each period in the past has cast its footprints on the landscape development and its potential for a sustainable future use. On a regional level there has been a continual decrease in forest area over time. Expansion of agriculture around planned villages, implemented during the 1970s, in some cases equals the loss of forest area (Mikumi-Ulaya), whilst in other areas (Kitulangalo), the pre-independence loss of woodland was small; the agricultural area was almost the same during the period 1975–1999, despite the fact that forests have been lost at an almost constant rate over the same period. Illegal logging and charcoal production are likely causes because of the proximity to the main highway running through the area. Contrasting to the general regional pattern are the conditions in a traditional village (Ihombwe), with low immigration of people and a maintained knowledge of the resource potential of the forest with regards to edible plants and animals. In this area the local community has control of the forest resources in a Forest Reserve, within which the woody vegetation has increased in spite of an expansion of agriculture on other types of village land. The mapping procedure has shown that factors such as access to transport and lack of local control have caused greater deforestation of certain areas than during the colonial period. Planned villages have furthermore continued to expand over forest areas well after their implementation, rapidly increasing the landscape fragmentation. One possible way to maintain landscape and biodiversity values is by the sustainable use of traditional resources, based on local knowledge of their management as illustrated by the little change observed in the traditionally used area.

  • 210. Sun, H
    et al.
    Luo, Y
    Alexandersson, Ronny
    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.
    Ge, S
    Pollination biology of the deceptive orchid Changnienia amoena2006In: Botanical Journal of the Linnean Society, Vol. 150, p. 165-175Article in journal (Refereed)
  • 211. Sun, Hai-Qin
    et al.
    Alexandersson, Ronny
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ge, Song
    Positive effects of flower abundance and synchronous flowering on pollination success, and pollinia dispersal in rewardless Changnienia amoena (Orchidaceae)2010In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 99, no 3, p. 477-488Article in journal (Refereed)
    Abstract [en]

    Pollination success and pollen dispersal in natural populations depend on the spatial-temporal variation of flower abundance. For plants that lack rewards for pollinators, pollination success is predicted to be negatively related to flower density and flowering synchrony. We investigated the relationships between pollination success and flower abundance and flowering synchrony, and estimated pollinia dispersal distance in a rewardless species, Changnienia amoena (Orchidaceae). The results obtained in the present study revealed that male pollination success was negatively influenced by population size but was positively affected by population density, whereas female pollination success was independent of both population size and density. Phenotypic analysis suggested that highly synchronous flowering was advantageous through total pollination success, which is in contrast to previous studies. These results indicate that pollination facilitation rather than competition for pollinator visits occurs in this rewardless plant. The median distance of pollinia dispersal was 11.5 m (mean distance = 17.5 m), which is comparable to that of other rewardless plants but longer than for rewarding plants. However, pollen transfer occured mainly within populations; pollen import was a rare event. Restricted gene flow by pollinia and seeds probably explains the previous population genetic reporting a high degree of genetic differentiation between populations.

  • 212.
    Sundberg, Sebastian
    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.
    Larger capsules enhance short-range spore dispersal in Sphagnum, but what happens further away?2005In: Oikos, Vol. 108, p. 115-124Article in journal (Refereed)
  • 213.
    Sundberg, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Size matters for violent discharge height and settling speed of Sphagnum spores: important attributes for dispersal potential2010In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 105, no 2, p. 291-300Article in journal (Refereed)
    Abstract [en]

    Initial release height and settling speed of diaspores are biologically controlled components which are key to modelling wind dispersal. Most Sphagnum (peat moss) species have explosive spore liberation. In this study, how capsule and spore sizes affect the height to which spores are propelled were measured, and how spore size and spore number of discharged particles relate to settling speed in the aspherical Sphagnum spores. Spore discharge and spore cloud development were filmed in a closed chamber (nine species). Measurements were taken from snapshots at three stages of cloud development. Settling speed of spores (14 species) and clusters were timed in a glass tube. The maximum discharge speed measured was 3 center dot 6 m s(-1). Spores reached a maximum height of 20 cm (average: 15 cm) above the capsule. The cloud dimensions at all stages were related positively to capsule size (R-2 = 0 center dot 58-0 center dot 65). Thus species with large shoots (because they have large capsules) have a dispersal advantage. Half of the spores were released as singles and the rest as clusters (usually two to four spores). Single spores settled at 0 center dot 84-1 center dot 86 cm s(-1), about 52 % slower than expected for spherical spores with the same diameters. Settling speed displayed a positive curvilinear relationship with spore size, close to predictions by Stokes' law for spherical spores with 68 % of the actual diameters. Light-coloured spores settled slower than dark spores. Settling speed of spore clusters agrees with earlier studies. Effective spore discharge and small, slowly settling spores appear particularly important for species in forested habitats. The spore discharge heights in Sphagnum are among the greatest for small, wind-dispersed propagules. The discharge heights and the slow settling of spores affect dispersal distances positively and may help to explain the wide distribution of most boreal Sphagnum species.

  • 214.
    Sundberg, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Udda fynd av vitmossor Sphagnum och parasollmossor (Splachnaceae) i Uppland och Hälsingland2009In: Myrinia, ISSN 1102-4194, Vol. 19, no 2, p. 58-65Article in journal (Other academic)
  • 215.
    Sundberg, Sebastian
    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.
    Åtgärdsprogram för bevarande av rikkärr, inklusive arterna gulyxne Liparis loeselii (NT), kalkkärrsgrynsnäcka Vertigo geyeri (NT) och större agatsnäcka Cochlicopa nitens (EN)2006Report (Other scientific)
  • 216.
    Sundberg, Sebastian
    et al.
    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.
    Hansson, J
    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.
    Colonisation of Sphagnum on land uplift islands in the Baltic Sea: time, area, distance and life history2006In: Journal of Biogeography, Vol. 33, p. 1479-1491Article in journal (Refereed)
  • 217. Suyama, Yoshihisa
    et al.
    Gunnarsson, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Parducci, Laura
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Functional Genomics.
    Analysis of short DNA fragments from Holocene peatmoss samples2008In: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 18, no 6, p. 1003-1006Article in journal (Refereed)
    Abstract [en]

    This paper describes our recent attempt to isolate and analyse DNA from old plant remains of the common peatmoss Sphagnum fuscum retrieved from a peat core collected in the mire Fuglmyra, in central Norway. DNA was recoverable and usable from sub-fossilized (10–450 years old) plant remains of the peatmoss. A chloroplast (trnL) and two nuclear (ITS2 and RAPDf) regions were co-amplified from 80 samples of different ages. The RAPDf region was the only variable one with three different haplotypes found among five samples. Comparison of the ancient sequences with modern sequences found in the extant population occurring at the same site ascertained a genetic link between modern and fossil samples of this species. This retrieval of ancient DNA from sub-fossilized moss remains isolated from peat cores has important implications for the palaeoecology of peatmosses by allowing direct estimates of plant population dynamics in space and time.

  • 218.
    Svensson, Brita
    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.
    Recension av Botaniska utflykter i Bohuslän2006In: Svensk Botanisk Tidskrift, Vol. 100, p. 210-Article, book review (Other (popular scientific, debate etc.))
  • 219.
    Svensson, Brita
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Carlsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    How can we protect rare hemiparasitic plants? Early-flowering taxa of Euphrasia and Rhinanthus on the Baltic island of Gotland2005In: Folia Geobotanica, ISSN 1211-9520, E-ISSN 1874-9348, Vol. 40, no 2-3, p. 261-272Article in journal (Refereed)
    Abstract [en]

    Euphrasia stricta var.suecica, E. stricta var.tenuis, andRhinanthus serotinus subsp.vernalis are three endangered, hemiparasitic annual herbs found in traditionally managed hay meadows on Gotland, Sweden. We have studied — experimentally and in the field — how some features in the present and traditional management cycle affect their fitness.

    We set up permanent 50 × 50-cm plots in a coastal hay meadow where bothE. stricta var.suecica andRhinanthus are still quite common. The survival, growth and fecundity of cohorts ofEuphrasia andRhinanthus were followed throughout the growing season for three years. The length of the growing season was vital forEuphrasia andRhinanthus performance. In cooler summers, the percentage ofEuphrasia individuals that produced mature seeds was decreased by 20% at the time of mowing. This indicates the need to individually adjust the time of mowing, as was formerly done, to the actual phenological development in order to maintain healthy populations. It is also important to consider the effect of time of mowing on total species richness, asEuphrasia more successfully established in 10 × 10-cm squares with high species richness. Also, the time in spring when hemiparasite growth started was crucial. Cohorts of bothEuphrasia stricta var.suecica andRhinanthus that connected to hosts and started growing early in the season had a strong advantage over later cohorts by having fitness values four to eight times higher. From this we conclude that the traditional practice of spring raking is important for the long-term persistence of these hemiparasites, since raking promotes an earlier onset of both host and hemiparasite growth. Another important issue is the traditional, but nowadays often neglected practice of letting the hay dry in the meadow after mowing. Hay that was left to dry in the meadow contributed significantly moreRhinanthus seed to the meadow than hay that was taken away immediately after mowing. We also found that seedling emergence and subsequent growth ofEuphrasia stricta var.suecica was greatly enhanced by a second hay cut in September. A second cutting mimics some of the positive effects of the traditional practice of aftermath grazing, which is nowadays often abandoned.

  • 220.
    Svensson, Brita
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Carlsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Significance of time of attachment, host type, and neighbouring hemiparasites in determining fitness in two endangered grassland hemiparasites2004In: Annales Botanici Fennici, Vol. 41, p. 63-75Article in journal (Refereed)
  • 221.
    Svensson, Brita
    et al.
    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.
    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.
    Carlsson, Bengt
    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.
    Clonal plants in the community2005In: Vegetation ecology, Blackwell, Oxford , 2005, p. 129-146Chapter in book (Refereed)
  • 222. Tenow, Olle
    et al.
    Bylund, Helena
    Nilssen, AC
    Karlsson, P Staffan
    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.
    Long-term influence of herbivores on northern birch forests2005In: Plant ecology, herbivory, and human impact in Nordic mountain birch forests, Springer-Verlag, Berlin , 2005, p. 166-181Chapter in book (Refereed)
  • 223.
    Toräng, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Korta växter snyltar på grannarna2007In: Forskning & Framsteg, ISSN 0015-7937, no 4, p. 36-39Article in journal (Other (popular science, discussion, etc.))
  • 224.
    Toräng, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ehrlen, Johan
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Linking environmental and demographic data to predict future population viability of a perennial herb2010In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 163, no 1, p. 99-109Article in journal (Refereed)
    Abstract [en]

    Recent advances in stochastic demography provide tools to examine the importance of random and periodic variation in vital rates for population dynamics. In this study, we explore with simulations the effect of disturbance regime on population dynamics and viability. We collected 7 years of demographic data in three populations of the perennial herb Primula farinosa, and used these data to examine how variation in vital rates affected population viability parameters (stochastic growth rate, lambda(S)), and how vital rates were related to weather conditions. Elasticity analysis indicated that the stochastic growth rate was very sensitive to changes in regeneration, quantified as the production, survival, and germination of seeds. In one of the study years, all seedlings and mature plants in the demography plots died. This extinction coincided with the driest summer during the study period. Simulations suggested that a future increase in the frequency of high-mortality years due to climate change would result in reduced population growth rate, and an increased importance of survival in the seed bank for population viability. The results illustrate how the limited demographic data typically available for many natural systems can be used in simulation models to assess how environmental change will affect population viability.

  • 225.
    Toräng, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ehrlén, Johan
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Facilitation in an insect pollinated herb with a floral display dimorphism2006In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 87, no 8, p. 2113-2117Article in journal (Refereed)
    Abstract [en]

    Population context should influence pollination success and selection on. oral display in animal-pollinated plants because attraction of pollinators depends not only on the characteristics of individual plants, but also on the attractiveness of co-occurring conspecifics. The insect-pollinated herb Primula farinosa is polymorphic for inflorescence height. Natural populations may include both long-scaped plants, which present their flowers well above the soil surface, and short-scaped plants, with their flowers positioned close to the ground. We experimentally tested whether seed production in short-scaped P. farinosa varied with local morph frequency and surrounding vegetation height. In tall vegetation, short-scaped plants in polymorphic populations produced more fruit and tended to produce more seeds than short-scaped plants did in monomorphic populations. In low vegetation, population composition did not significantly affect fruit and seed output of short-scaped plants. The results suggest that long-scaped plants facilitate short-scaped plants in terms of pollinator attraction and that the facilitation effect is contingent on the height of the surrounding vegetation. The documented facilitation should contribute to the maintenance of the scape length polymorphism in ungrazed areas where litter accumulates and vegetation grows tall.

  • 226.
    Toräng, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ehrlén, Johan
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Mutualists and antagonists mediate frequency-dependent selection on floral display2008In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 89, no 6, p. 1564-1572Article in journal (Refereed)
    Abstract [en]

    Theory predicts that, with conflicting selection pressures mediated by mutualists and antagonists, alternative reproductive strategies can be maintained by negative frequency-dependent selection if it results in rare-morph advantage. We combined field experiments and surveys of natural populations to determine whether selection on. oral display is frequency dependent in the self-incompatible herb Primula farinosa, which is polymorphic for inflorescence height and occurs in a short-scaped and a long-scaped morph. Among short-scaped plants, both pollination success, quantified as initiation of fruits and seeds, and seed predation were positively correlated with the relative frequency of the long-scaped morph. The relative strength of these effects and the direction of the resulting frequency-dependent selection on scape morph varied among years and populations. The results suggest that both mutualists and antagonists may mediate frequency-dependent selection and that frequency dependence may vary from positive to negative with rare-morph advantage, depending on the relative strength of these interactions.

  • 227. Traveset, A
    et al.
    Jakobsson, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany. Växtekologi.
    Ecology of plant reproduction: Mating systems and pollination2007In: Functional Plant Ecology, 2007Chapter in book (Refereed)
  • 228.
    Udd, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Är vassen ett hot mot rikkärren?2008In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 102, no 2, p. 85-98Article in journal (Refereed)
  • 229.
    Ulanova, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Busse, Svenja
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Snoeijs, Pauli
    Coastal diatom-environment relationships in the brackish Baltic Sea2009In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 45, no 1, p. 54-68Article in journal (Refereed)
    Abstract [en]

    High-quality calibration data sets are required when diatom assemblages are used for monitoring ecological change or reconstructing palaeo-environments. The quality of such data sets can be validated, in addition to other criteria, by the percentage of significant unimodal species responses as a measure of the length of an environmental gradient. This study presents diatom-environment relationships analyzed from a robust data set of diatom communities living on submerged stones along a 2,000 km long coastline in the Baltic Sea area, including 524 samples taken at 135 sites and covering a salinity gradient from 0.4 to 11.4. Altogether, 487 diatom taxa belonging to 102 genera were recorded. Detrended canonical correspondence analysis showed that salinity was the overriding environmental factor regulating diatom community composition, while exposure to wave action and nutrient concentrations were of secondary importance. Modeling the abundances of the 58 most common diatom taxa yielded significant relationships with salinity for 57 taxa. Twenty-three taxa showing monotonic responses were species with optimum distributions in freshwater or marine waters. Thirty-four taxa showing unimodal responses were brackish-water species with maximum distributions at different salinities. Separate analyses for small (cell biovolume <1,000 μm3) and large (≥1,000 μm3) taxa yielded similar results. In previous studies along shorter salinity gradients, large and small epilithic diatom taxa responded differently. From our large data, we conclude that counts of large diatom taxa alone seem sufficient for indicating salinity changes in coastal environments with high precision.

  • 230.
    Ulanova, Anna
    et al.
    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.
    Snoeijs, Pauli
    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.
    Gradient responses of epilithic diatom communities in the Baltic Sea proper2006In: Estuarine, Coastal and Shelf Science, Vol. 68, p. 661-674Article in journal (Refereed)
  • 231.
    Ursi, S., Pedersén, M., Plastino, E. and Snoeijs, P.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. PLANT ECOLGY.
    Intraspecific variation of photosynthesis, respiration and photoprotective carotenoids in Gracilaria birdiae (Gracilariales: Rhodophyta)2003In: Marine Biology, Vol. 142, p. 997-1007Article in journal (Refereed)
  • 232.
    van der Maarel, Eddy
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Book review of Baskin, C. C. and Baskin, J. B. 1998. Seeds. Ecology, biogeography, and evolution of dormancy and germination2001In: Journal of Vegetation Science, Vol. 12, p. 302-303Article, book review (Refereed)
  • 233.
    van der Maarel, Eddy
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Long-term environmental monitoring2002In: Encyclopedia of environmetrics, vol. 2, Wiley , 2002, p. 1189-1195Chapter in book (Refereed)
  • 234. van Groenendael, Jan
    et al.
    Ehrlén, Johan
    Svensson, Brita M.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Dispersal and persistence: population processes and community dynamics2000In: Folia Geobotanica, ISSN 1211-9520, E-ISSN 1874-9348, Vol. 35, no 2, p. 107-114Article in journal (Refereed)
  • 235.
    van Nieuwerburgh, L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Wänstrand, I
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Snoeijs, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Growth and C:N:P ratios in copepods grazing on N- or Si-limited phytoplankton bloom2004In: Hydrobiologia, Vol. 514, p. 57-72Article in journal (Refereed)
  • 236. Vanhoenacker, D
    et al.
    Ågren, Jon
    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.
    Ehrlén, Johan
    Spatio-temporal variation in pollen limitation and reproductive success of two scape morphs in Primula farinosa2006In: New Phytologist, Vol. 169, p. 615-621Article in journal (Refereed)
  • 237. Vanhoenacker, Didrik
    et al.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ehrlén, Johan
    Spatial variability in seed predation in Primula farinosa: local population legacy vs. patch selection2009In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 160, no 1, p. 77-86Article in journal (Refereed)
    Abstract [en]

    Spatio-temporal variation in seed predation may strongly influence both plant population dynamics and selection on plant traits. The intensity of seed predation may depend on a number of factors, but the relative importance of previous predator abundance (“local legacy”), spatial distribution of the host plant, environmental factors and plant characteristics has been explored in few species. We monitored seed predation in the perennial herb Primula farinosa, which is dimorphic for scape length, during 5 consecutive years, in a 10-km × 4-km area comprising 79 P. farinosa populations. A transplant experiment showed that the seed predator, the oligophagous tortricid moth Falseuncaria ruficiliana, was not dispersal limited at the spatial scale corresponding to typical distances between P. farinosa populations. Correlations between population characteristics and incidence and intensity of seed predation varied among years. The incidence of the seed predator was positively correlated with host population size and mean number of flowers, while intensity of seed predation in occupied patches was positively related to the frequency of the long-scaped morph in 2 years and negatively related to host population size in 1 year. In both scape morphs, predation tended to increase with increasing frequency of the long morph. There was no evidence of a local legacy; incidence and intensity of seed predation were not related to the abundance of the seed predator in the population in the previous year. Taken together, the results indicate that among-population variation in seed predation intensity is determined largely by patch selection and that the seed predator’s preference for tall and many-flowered inflorescences may not only affect selection on plant traits within host plant populations, but also the overall intensity of seed predation.

  • 238. Waites, A.R.
    et al.
    Ågren, Jon
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Pollinator visitation, stigmatic pollen loads, and among-population variation in seed set in Lythrum salicaria2004In: Journal of Ecology, Vol. 92, p. 512-526Article in journal (Refereed)
  • 239. Waites, AR
    et al.
    Ågren, Jon
    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.
    Stigma receptivity and effects of prior self-pollination on seed set in tristylous Lythrum salicaria (Lythraceae)2006In: American Journal of Botany, Vol. 93, p. 142-147Article in journal (Refereed)
  • 240.
    Wallin, Lotta
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Plant Population Dynamics and Conservation in Wooded Hay-Meadows – Effects of Intensified Management2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The decrease in number and area of managed hay-meadows over the last century, in combination with the reduction of traditional management, threatens the biodiversity connected to these habitats. I experimentally examined how management intensity affected meadow characteristics and long-term population viability of three vascular plant species in wooded hay-meadows on the Swedish island of Gotland in the Baltic Sea. I discovered that intensified management (extra raking and/or extra mowing) reduced the amount of litter and biomass, even in well-managed meadows.

    The effects of intensified management on population growth rate varied among species. Deterministic demographic models revealed that intensified management increased population growth rate in Succisa pratensis. Stochastic modelling confirmed this; all meadows displayed larger projected population sizes 50 years into the future with intensified management. Polygala amarella responded with lower growth rates in raked plots, a consequence of the plant’s morphology, which makes it prone to being pulled out by raking. Hypochoeris maculata had population growth rates close to unity, and showed no response to an increase in management. Examination of the life-history characteristics of Polygala amarella showed that the species’ strategy is aimed at reproduction and fast growth, which is in contrast to the other two species, with their success relying on the survival of older plants. The species-specific responses to management show that several species should be considered when evaluating management practices for conservation of semi-natural grasslands. Furthermore, I suggest that data on stage distributions alone may not be sufficient for identifying threatened populations.

    In a study of artificial dispersal between meadows, I found that establishment was twice as successful for planted plug-plants compared to sown seeds. Both methods may be useful for introducing or augmenting meadow populations, depending on access to seed sources and possibilities to nurse plants.

    An electronic coordinate measurement device for gathering location data to be used in demographic studies was developed. In the field, the device proved to be a simple and reliable method for locating individuals in permanent plots.

    List of papers
    1. Effects of intensified management of hay-meadows on population dynamics of Succisa pratensis
    Open this publication in new window or tab >>Effects of intensified management of hay-meadows on population dynamics of Succisa pratensis
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-95585 (URN)
    Available from: 2007-03-26 Created: 2007-03-26 Last updated: 2010-01-13Bibliographically approved
    2. Intensified management affects population growth differently in the two perennial herbs Hypochoeris maculata and Polygala amarella
    Open this publication in new window or tab >>Intensified management affects population growth differently in the two perennial herbs Hypochoeris maculata and Polygala amarella
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-95586 (URN)
    Available from: 2007-03-26 Created: 2007-03-26 Last updated: 2010-01-13Bibliographically approved
    3. Artificial dispersal as a restoration tool in meadows: sowing or planting?
    Open this publication in new window or tab >>Artificial dispersal as a restoration tool in meadows: sowing or planting?
    2009 (English)In: Restoration Ecology, ISSN 1061-2971, E-ISSN 1526-100X, Vol. 17, no 2, p. 270-279Article in journal (Refereed) Published
    Abstract [en]

    Habitat fragmentation and the abandonment of former agricultural   practices have led to extremely low dispersal rates for plant species   growing in traditionally managed hay meadows in Sweden. Historically,   seed dispersal between populations was maintained by hay movement,   grazing animals, and farmers sharing their equipment. Because these   means of dispersal typically are no longer occurring, artificial   dispersal using seeds and plug-plants is tested here as a restoration   tool. In this study, we chose two perennial herbs commonly occurring in   meadows as test species, viz, Hypochoeris maculata L. (Asteraceae) and   Succisa pratensis Moench. (Dipsacaceae). We found that plug-plant   transplants were twice as effective as seed sowing for both species.   The seed collection site was found to be important for seed-based   establishment and survival; consequently, the choice of donor meadow is   important when acquiring seeds used for restoration. We also found that   survival of plants introduced as seeds was generally lower at sites   harboring species favored by nitrogen as well as at sites in later   successional phases. Both methods of introducing meadow species worked   well, even though long-term establishment may well be more successful   with the plug-plant method due to higher plug-plant establishment 2   years after introduction in the field.

    Keywords
    hay meadow, Hypochoeris maculata, plug-plant transplantation, population augmentation, seed sowing, Succisa pratensis
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-95587 (URN)10.1111/j.1526-100X.2007.00350.x (DOI)000263911000012 ()
    Available from: 2007-03-26 Created: 2007-03-26 Last updated: 2017-12-14Bibliographically approved
    4. A timesaving, accurate method for locating and re-locating plants in ecological field studies
    Open this publication in new window or tab >>A timesaving, accurate method for locating and re-locating plants in ecological field studies
    2007 (English)In: Ecological Informatics, ISSN 1574-9541, Vol. 2, no 4, p. 367-372Article in journal (Refereed) Published
    Abstract [en]

    We present a method for increasing the accuracy and acquisition rate of the initial location data of plants within fixed areas. Using a personal digital assistant (PDA) to create a link between various electronic measurement devices (pantograph, micrometers etc.) and a database of the study individual's location information, has significantly increased measurement reliability and speed in a demographic field study. The method also provides a means to quickly and accurately re-identify the same individuals during subsequent visits to the study plot. Application of the same method can be used in all ecological field studies with sessile organisms in permanent plots, increasing speed and accuracy of coordinate measurement.

    Keywords
    database, demographic study, pantograph, permanent plot, coordinate measuring
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-95588 (URN)10.1016/j.ecoinf.2007.03.003 (DOI)000252061200008 ()
    Available from: 2007-03-26 Created: 2007-03-26 Last updated: 2010-03-16Bibliographically approved
  • 241.
    Wallin, Lotta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Avery, Hamish R. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    A timesaving, accurate method for locating and re-locating plants in ecological field studies2007In: Ecological Informatics, ISSN 1574-9541, Vol. 2, no 4, p. 367-372Article in journal (Refereed)
    Abstract [en]

    We present a method for increasing the accuracy and acquisition rate of the initial location data of plants within fixed areas. Using a personal digital assistant (PDA) to create a link between various electronic measurement devices (pantograph, micrometers etc.) and a database of the study individual's location information, has significantly increased measurement reliability and speed in a demographic field study. The method also provides a means to quickly and accurately re-identify the same individuals during subsequent visits to the study plot. Application of the same method can be used in all ecological field studies with sessile organisms in permanent plots, increasing speed and accuracy of coordinate measurement.

  • 242.
    Wallin, Lotta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Svensson, Brita M.
    Effects of intensified management of hay-meadows on population dynamics of Succisa pratensisManuscript (Other academic)
  • 243.
    Wallin, Lotta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Svensson, Brita M.
    Intensified management affects population growth differently in the two perennial herbs Hypochoeris maculata and Polygala amarellaManuscript (Other academic)
  • 244.
    Wallin, Lotta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Svensson, Brita M.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Lönn, Mikael
    Artificial dispersal as a restoration tool in meadows: sowing or planting?2009In: Restoration Ecology, ISSN 1061-2971, E-ISSN 1526-100X, Vol. 17, no 2, p. 270-279Article in journal (Refereed)
    Abstract [en]

    Habitat fragmentation and the abandonment of former agricultural   practices have led to extremely low dispersal rates for plant species   growing in traditionally managed hay meadows in Sweden. Historically,   seed dispersal between populations was maintained by hay movement,   grazing animals, and farmers sharing their equipment. Because these   means of dispersal typically are no longer occurring, artificial   dispersal using seeds and plug-plants is tested here as a restoration   tool. In this study, we chose two perennial herbs commonly occurring in   meadows as test species, viz, Hypochoeris maculata L. (Asteraceae) and   Succisa pratensis Moench. (Dipsacaceae). We found that plug-plant   transplants were twice as effective as seed sowing for both species.   The seed collection site was found to be important for seed-based   establishment and survival; consequently, the choice of donor meadow is   important when acquiring seeds used for restoration. We also found that   survival of plants introduced as seeds was generally lower at sites   harboring species favored by nitrogen as well as at sites in later   successional phases. Both methods of introducing meadow species worked   well, even though long-term establishment may well be more successful   with the plug-plant method due to higher plug-plant establishment 2   years after introduction in the field.

  • 245.
    Wallrup, Emma
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Saetre, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Deciduous trees affect small-scale floristic diversity and tree regeneration in conifer forests2006In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 21, no 5, p. 399-404Article in journal (Refereed)
    Abstract [en]

    There is a growing interest in the effects of deciduous trees on biodiversity, soil processes and long-term productivity in boreal, conifer-dominated forests. This study investigated whether individual birch trees allowed to grow to maturity in the coniferous forest can have a local effect on floristic richness and regeneration of tree saplings. The ground vegetation was compared in 2 m radius plots around the stem under the canopies of matched conifer-deciduous trees in a mature, conifer-dominated forest, and included in the analysis variables that could potentially mediate the tree effect (soil pH, cover of lichens, bryophytes, leaf and needle litter). The field layer vegetation was more species rich under birch (Betula pendula and B. pubescens) than under conifers (Picea abies and Pinus sylvestris), and several vascular plant species (including saplings of tree species) occurred more often under birch than under conifers. However, when the effect of the number of subordinate trees was taken into account the difference between birch and pine was not significant. The number of tree regenerations (saplings) was lowest under pines, but did not differ between spruce and birch. There were no effects of the canopy species on soil pH or on cover of lichens and bryophytes. The difference in diversity may be caused by the different effects of leaf and needle litter, and it is also likely that canopy structure has an influence via interception and throughfall and by affecting the light and microclimate.

  • 246. Weibull, Henrik
    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.
    Bryophyte species richness on boulders: relationship to area, habitat diversity and canopy tree species2005In: Biological Conservation, Vol. 122, p. 71-79Article in journal (Refereed)
  • 247.
    Weih, M., Karacic, A., Munkert, H., Verwijst and Diekmann, M.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. PLANT ECOLGY.
    Influence of young poplar stands on floristic diversity in agricultural landscapes (Sweden)2003In: Basic and Applied Ecology, Vol. 4, p. 149-156Article in journal (Refereed)
  • 248.
    Weih, Martin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Karlsson, P Staffan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Growth response of mountain birch to air and soil temperature: is increasing leaf-nitrogen content an acclimation to lower air temperature?2001In: New Phytologist, Vol. 150, p. 147-155Article in journal (Refereed)
  • 249.
    Weih, Martin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Karlsson, P Staffan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Variation in growth patterns among provenances, ecotypes and individuals of mountain birch2001In: Nordic mountain birch ecosystems, Parthenon/UNESCO , 2001, p. 143-154Chapter in book (Refereed)
  • 250. Wiederman, Magdalena
    et al.
    Nordin, Annica
    Gunnarsson, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Nilsson, Mats
    Ericson, Lars
    Global change shifts vegetation and plant-parasite interactions in a boreal mire2007In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 88, no 2, p. 454-464Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to detect vegetation change and to examine trophic interactions in a Sphagnum-dominated mire in response to raised temperature and nitrogen (N) addition. A long-term global-change experiment was established in 1995, with monthly additions of N ( 30 kg.ha(-1).yr(-1)) and sulfur (20 kg.ha(-1)yr(-1)) during the vegetation period. Mean air temperature was raised by 3.6 degrees C with warming chambers. Vegetation responses were negligible for all treatments for the first four years, and no sulfur effect was seen during the course of the experiment. However, after eight years of continuous treatments, the closed Sphagnum carpet was drastically reduced from 100% in 1995 down to 41%, averaged over all N-treated plots. Over the same period, total vascular plant cover ( of the graminoid Eriophorum vaginatum and the two dwarf-shrubs Andromeda polifolia and Vaccinium oxycoccos) increased from 24% to an average of 70% in the N plots. Nitrogen addition caused leaf N concentrations to rise in the two dwarf-shrubs, while for E. vaginatum, leaf N remained unchanged, indicating that the graminoid to a larger extent than the dwarf-shrubs allocated supplemented N to growth. Concurrent with foliar N accumulation of the two dwarf-shrubs, we observed increased disease incidences caused by parasitic fungi, with three species out of 16 showing a significant increase. Warming caused a significant decrease in occurrence of three parasitic fungal species. In general, decreased disease incidences were found in temperature treatments for A. polifolia and in plots without N addition for V. oxycoccos. The study demonstrates that both bryophytes and vascular plants at boreal mires, only receiving background levels of nitrogen of about 2 kg.ha(-1)yr(-1), exhibit a time lag of more than five years in response to nitrogen and temperature rise, emphasizing the need for long-term experiments. Moreover, it shows that trophic interactions are likely to differ markedly in response to climate change and increased N deposition, and that these interactions might play an important role in controlling the change in mire vegetation composition, with implications for both carbon sequestration and methane emission.

23456 201 - 250 of 259
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