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  • 101.
    Karlsson, P. S., Bylund, H, Neuvonen, S., Heino, S. and Tjus, 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.
    Climatic control of budburst in the mountain birch at two areas in northern Fennoscandia and possible responses to global change2003In: Ecography, Vol. 27, p. 617-625Article in journal (Refereed)
  • 102.
    Karlsson, P. Staffan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Andersson, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Svensson, Brita
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Relationships between fruit production and branching in monocarpic shoot modules of Rhododendron lapponicum2006In: Ecoscience, ISSN 1195-6860, Vol. 13, no 3, p. 396-403Article in journal (Refereed)
    Abstract [en]

    Rhododendron lapponicum is an ericaceous clonal dwarf shrub in which vegetative growth largely coincides with the formation of flowers and fruits. We used a flower-removal experiment and a descriptive data set to look for relationships and potential trade-offs between vegetative growth, i.e., branching, and fruit production in two contrasting subarctic populations (growing at low and high altitude). The two sites are similar in most respects and differ mainly in that the higher site has lower temperatures and a shorter growing season. We predicted that trade-offs between branching and fruit production would be less marked in a high-altitude population because at lower temperatures reproductive activities could be less resource dependent. At lower altitudes, where temperatures are higher, there would be competition for nutrients between fruiting and branching; hence, a trade-off between these two activities would be more obvious. In both populations about 80% of all new shoot modules were produced by reproductive shoot modules. We found evidence for a [linear] trade-off in the experimental study only, whereas the descriptive data set did not show any consistent indications of trade-offs between branch and fruit production. The high-altitude population showed several characteristics indicating that this population gave priority to vegetative growth over sexual reproduction. The data we present is a typical example of a case where co-variation in size and resource economy among modules masks potential trade-off patterns.

  • 103.
    Karlsson, P. Staffan
    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.
    Bylund, H
    Tenow, O
    Fjällbjörkskogen - ett helt ekosystem som styrs av en liten fjäril2004In: Svensk Botanisk Tidskrift, Vol. 98, p. 161-172Article in journal (Refereed)
  • 104.
    Karlsson, P Staffan
    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.
    Nordell, K Olle
    Sveinbjörnsson, Bjartmar
    Biomass and nitrogen turnover and nutrient use characteristics in subarctic mountain birch trees2001In: Nordic mountain birch ecosystems, Parthenon/UNESCO , 2001, p. 127-141Chapter in book (Refereed)
  • 105.
    Karlsson, P. Staffan
    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.
    Tenow, O
    Bylund, H
    Hoogesteger, J
    Weih, M
    Determinants of mountain birch growth in situ: effects of temperature and herbivory2004In: Ecography, Vol. 27, p. 659-667Article in journal (Refereed)
  • 106.
    Karlsson, P Staffan
    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.
    Weih, Martin
    Borg, Christina
    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.
    Mountain birch growth in relation to climate and herbivores2005In: Plant ecology, herbivory, and human impact in Nordic mountain birch forests, 2005, p. 71-86Chapter in book (Refereed)
  • 107.
    Karlsson, P Staffan
    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.
    Wielgolaski, FE
    Synthesis section 1: A dynamic forest in a changing environment2005In: Plant ecology, herbivory, and human impact in Nordic mountain birch forests, Springer-Verlag, Berlin , 2005, p. 117-122Chapter in book (Refereed)
  • 108.
    Karlsson, PS
    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.
    Jacobsson, A
    Onset of reproduction in Rhododendron lapponicum shoots: the effect of shoot size, age, and nutrient status at two subarctic sites2001In: Oikos, Vol. 94, p. 279-286Article in journal (Refereed)
  • 109.
    Karlsson, PS
    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.
    Weih, M
    Soil temperatures near the distribution limit of the mountain birch (Betula pubescens ssp. czerepanovii): implications for seedling nitrogen economy and survival2001In: Arctic, Antarctic and Alpine Research, Vol. 33, p. 88-92Article in journal (Refereed)
  • 110.
    Kebrom, Tekle
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Natural regeneration of degraded hill slopes in Southern Wello, Ethiopia: a study based on permanent plots2001In: Applied Geography, Vol. 21, p. 275-300Article in journal (Refereed)
  • 111. Kivimäki, Maarit
    et al.
    Kärkkäinen, Katri
    Gauldeul, Myriam
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Løe, Geir
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Gene, phenotype and function: GLABROUS1 and resistance to herbivory in natural populations of Arabidopsis lyrata2007In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 16, no 2, p. 453-462Article in journal (Refereed)
    Abstract [en]

    The molecular genetic basis of adaptive variation is of fundamental importance for evolutionary dynamics, but is still poorly known. Only in very few cases has the relationship between genetic variation at the molecular level, phenotype and function been established in natural populations. We examined the functional significance and genetic basis of a polymorphism in production of leaf hairs, trichomes, in the perennial herb Arabidopsis lyrata. Earlier studies suggested that trichome production is subject to divergent selection. Here we show that the production of trichomes is correlated with reduced damage from insect herbivores in natural populations, and using statistical methods developed for medical genetics we document an association between loss of trichome production and mutations in the regulatory gene GLABROUS1. Sequence data suggest that independent mutations in this regulatory gene have provided the basis for parallel evolution of reduced resistance to insect herbivores in different populations of A. lyrata and in the closely related Arabidopsis thaliana. The results show that candidate genes identified in model organisms provide a valuable starting point for analysis of the genetic basis of phenotypic variation in natural populations.

  • 112. Klenell, Marcos
    et al.
    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.
    Pedersén, M
    Active carbon uptake in Laminaria digitata and Laminaria saccharina driven by a proton pump in the plasma membrane2004In: Hydrobiologia, Vol. 514, p. 41-53Article in journal (Refereed)
  • 113.
    Kolseth, Anna-Karin
    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.
    Lönn, Mikael
    Genetic structure of Euphrasia stricta on the Baltic island of Gotland, Sweden2005In: Ecography, Vol. 28, p. 443-452Article in journal (Refereed)
  • 114.
    Kolseth, Anna-Karin
    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.
    Lönn, Mikael
    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.
    Genetic structure in two meadow varieties of Euphrasia stricta on the Baltic island of Gotland (Sweden) and implications for conservation2005In: Folia Geobotanica, Vol. 40, p. 163-176Article in journal (Refereed)
  • 115. Kärkkäinen, K
    et al.
    Løe, Geir
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    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.
    Population structure in Arabidopsis lyrata: evidence for divergent selection on trichome production2004In: Evolution, Vol. 58, p. 2831-2836Article in journal (Refereed)
  • 116.
    Külheim, Carsetn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Jansson, Stefan
    Rapid Regulation of Light Harvesting and Plant Fitness in the Field.2002In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 297, no 5578, p. 91-93Article in journal (Refereed)
    Abstract [en]

    We used Arabidopsis thaliana mutants to examine how a photosynthetic regulatory process, the qE-type or ΔpH-dependent nonphotochemical quenching, hereafter named feedback de-excitation, influences plant fitness in different light environments. We show that the feedback de-excitation is important for plant fitness in the field and in fluctuating light in a controlled environment but that it does not affect plant performance under constant light conditions. Our findings demonstrate that the feedback de-excitation confers a strong fitness advantage under field conditions and suggest that this advantage is due to the increase in plant tolerance to variation in light intensity rather than tolerance to high-intensity light itself.                      

  • 117.
    Larsson, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Antalet blommande växter styr förekomst och täthet av vildbipopulationer2007In: Entomologisk Tidskrift, ISSN 0013-886X, Vol. 128, no 3, p. 89-92Article in journal (Refereed)
  • 118.
    Larsson, Magnus
    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.
    Higher pollinator effectiveness by specialist than generalist flower-visitors of unspecialized Knautia arvensis (Dipsacaceae)2005In: Oecologia, Vol. 146, p. 394-403Article in journal (Refereed)
  • 119.
    Larsson, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Franzén, Markus
    Critical resource levels of pollen for the declining bee Andrena hattorfiana (Hymenoptera, Andrenidae)2007In: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 134, no 3, p. 405-414Article in journal (Refereed)
    Abstract [en]

    The native bee fauna provides an important ecosystem function, but a large proportion of this fauna in Europe is threatened as a result of habitat loss and fragmentation. The solitary bee Andrena hattorfiana is specialised on collecting pollen from the plant-family Dipsacaceae. In northern Europe the major pollen resource is the insect-pollinated herb Knautia arvensis. We quantified the available K. arvensis resource, measured habitat characteristics and performed a flower-visitor survey in 57 well-defined K. arvensis populations in southern Sweden. There was a strong relationship between bee and plant population sizes. In populations with A. hattorfiana present (N=26), the female bees utilised on average 39% (12-80%) of the total available pollen resource. The nest architecture and nesting biology of A. hattorfiana is described for the first time. By excavating nests, we found that the provisioning for one average bee nest (containing 6 cells) required ca. 72 inflorescences or 11 plant individuals. The results suggest a certain minimum pollen amount needed to host an A. hattorfiana population. For example, for a population of ten reproducing A. hattorfiona female with the average degree of utilisation, the critical resource was predicted as 156 +/- 16 individuals (+/- SE) of the plant K. arvensis, which corresponds to 780 inflorescences or 36,731,978 pollen grains. These findings suggest that calculations via a 'pollen budget' can predict critical resources for a given size of specialised bee population, and thereby provide a tool in conservation.

  • 120.
    Larsson, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Franzén, Markus
    Estimating the population size of specialised solitary bees2008In: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 33, no 2, p. 232-238Article in journal (Refereed)
    Abstract [en]

    1. Reliable methods for quantifying population size are crucial for strategies to conserve endangered wild-bee species. Estimates of population size obtained through survey walks were compared with estimates obtained through mark–recapture studies in 10 populations of the red-listed solitary bee Andrena hattorfiana in southern Sweden.

    2. The mean number of bees observed during survey walks was strongly correlated with estimates of population size obtained with mark–recapture. It was found that 5.5–23.4% (mean 13.4%) of the total population was observed during an average survey walk.

    3. One component in mark–recapture analysis is the measure of survival of individuals. In the largest bee population, females of A. hattorfiana that emerged in early season were found to forage for pollen on average 18.4 days.

    4. The findings suggest that during large-scale surveys, for example re-inventories for red-listed species, the population size of solitary bees can be quantified reliably and effectively by performing survey walks in a two-step process. The first step consists of survey walks to establish the relationship between number of bee observations per survey walk and mark–recapture population size for a small set of populations. In the second, simple observation survey walks can be performed for a large set of populations. In each population of A. hattorfiana, it is recommended that at least six survey walks are performed.

  • 121. Leino, Matti W.
    et al.
    Hagenblad, Jenny
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Nineteenth Century Seeds Reveal the Population Genetics of Landrace Barley (Hordeum vulgare)2010In: Molecular biology and evolution, ISSN 0737-4038, E-ISSN 1537-1719, Vol. 27, no 4, p. 964-973Article in journal (Refereed)
    Abstract [en]

    Barley (Hordeum vulgare) is a major crop, grown worldwide and in a wide range of climatic conditions. Despite its importance as a crop species, little is known about the population genetics of barley and the effects of bottlenecks, adaptation, and gene flow on genetic diversity within and between landrace populations. In areas with highly developed agriculture, such as Northern Europe, these types of genetic studies are hampered by lack of landraces preserved in situ or ex situ. Here, we report a genetic study of Swedish landrace barley using 113-year-old seed samples. The results demonstrate differing levels of variation with some latitudinal effect. We also detect clear population differentiation and population structure within Sweden into a southern and a northern cluster. These results possibly reflect different introduction routes of barley into Sweden. We thus show that the study of historic material can be an important alternative for regions where no or little extant landrace material is available.

  • 122. Leino, Matti W.
    et al.
    Hagenblad, Jenny
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Edqvist, Johan
    Karlsson Strese, Else-Marie
    DNA preservation and utility of a historic seed collection2009In: Seed Science Research, ISSN 0960-2585, E-ISSN 1475-2735, Vol. 19, no 3, p. 125-135Article in journal (Refereed)
    Abstract [en]

    Historic collections of biological material are important genetic resources for taxonomic, evolutionary and historical research. In this paper we describe a seed collection dating from 1862 to 1918 maintained at the Swedish Museum of Cultural History. The collection contains over 3000 well-documented seed samples of various agricultural crops, mostly cereals. A subset of 100 samples divided over ten species frequently represented in the collection and a range of ages were tested for germinability and DNA preservation. None of these accessions were found to contain viable seeds. DNA extracted from the seeds was degraded, but the amount of degradation varied between species. DNA quality was evaluated by yield, fragment size and size of amplification product. Quality was highest for DNA extracted from Pisum sativum and Vicia sativa. DNA extracted from Brassica napus, Beta vulgaris and Trifolium pratense was more fragmented, and DNA extracted from Triticum aestivum, Secale sereale, Hordeum vulgare, Avena sativa and Phleum pratense was most degraded. Polymerase chain reaction (PCR) amplification of ribosomal DNA fragments of up to 700 bp was permitted for most samples in all species. To test whether single-copy nuclear genes could be amplified from the extracted DNA, microsatellite markers were used on the Pisum sativum and Hordeum vulgare samples. Polymorphisms of microsatellite markers were detected between samples for both species. The results show that the 19th-century seed collection can be utilized to infer genetic relationships among obsolete cultivars as well as for other types of genetic research based on sequence or marker analysis.

  • 123. Leinonen, Päivi H.
    et al.
    Sandring, Saskia
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Quilot, Bénédicte
    Clauss, Maria J.
    Mitchell-Olds, Thomas
    Ågren, Jon
    Savolainen, Outi
    Local adaptation in European populations of Arabidopsis lyrata (Brassicaceae)Manuscript (Other academic)
  • 124. Leinonen, Päivi H.
    et al.
    Sandring, Saskia
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Quilot, Bénédicte
    Clauss, Maria J.
    Mitchell-Olds, Thomas
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Savolainen, Outi
    Local adaptation in European populations of Arabidopsis lyrata (Brassicaceae)2009In: American Journal of Botany, ISSN 0002-9122, E-ISSN 1537-2197, Vol. 96, no 6, p. 1129-1137Article in journal (Refereed)
    Abstract [en]

    We studied local adaptation to contrasting environments usingan organism that is emerging as a model for evolutionary plantbiology—the outcrossing, perennial herb Arabidopsis lyratasubsp. petraea (Brassicaceae). With reciprocal transplant experiments,we found variation in cumulative fitness, indicating adaptivedifferentiation among populations. Nonlocal populations didnot have significantly higher fitness than the local population.Experimental sites were located in Norway (alpine), Sweden (coastal),and Germany (continental). At all sites after one year, thelocal population had higher cumulative fitness, as quantifiedby survival combined with rosette area, than at least one ofthe nonlocal populations. At the Norwegian site, measurementswere done for two additional years, and fitness differencespersisted. The fitness components that contributed most to differencesin cumulative fitness varied among sites. Relatively small rosettearea combined with a large number of inflorescences producedby German plants may reflect differentiation in life history.The results of the current study demonstrate adaptive populationdifferentiation in A. lyrata along a climatic gradient in Europe.The studied populations harbor considerable variation in severalcharacters contributing to adaptive population differentiation.The wealth of genetic information available makes A. lyrataa highly attractive system also for examining the functionaland genetic basis of local adaptation in plants.

  • 125. Limpens, J.
    et al.
    Berendse, F.
    Blodau, C.
    Canadell, J.G.
    Freeman, C.
    Holden, J.
    Roulet, N.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Schaepman-Strub, G.
    Peatlands and the carbon cycle: from local processes to global implications – a synthesis2008In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 5, no 5, p. 1475-1491Article, review/survey (Refereed)
    Abstract [en]

    Peatlands cover only 3% of the Earth's land surface but boreal and subarctic peatlands store about 15-30% of the world's soil carbon ( C) as peat. Despite their potential for large positive feedbacks to the climate system through sequestration and emission of greenhouse gases, peatlands are not explicitly included in global climate models and therefore in predictions of future climate change. In April 2007 a symposium was held in Wageningen, the Netherlands, to advance our understanding of peatland C cycling. This paper synthesizes the main findings of the symposium, focusing on (i) small-scale processes, (ii) C fluxes at the landscape scale, and (iii) peatlands in the context of climate change.

    The main drivers controlling most are related to some aspects of hydrology. Despite high spatial and annual variability in Net Ecosystem Exchange ( NEE), the differences in cumulative annual NEE are more a function of broad scale geographic location and physical setting than internal factors, suggesting the existence of strong feedbacks. In contrast, trace gas emissions seem mainly controlled by local factors.

    Key uncertainties remain concerning the existence of perturbation thresholds, the relative strengths of the CO2 and CH4 feedback, the links among peatland surface climate, hydrology, ecosystem structure and function, and trace gas biogeochemistry as well as the similarity of process rates across peatland types and climatic zones. Progress on these research areas can only be realized by stronger co-operation between disciplines that address different spatial and temporal scales.

  • 126. Lind, Henrik
    et al.
    Franzen, Markus
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Pettersson, Börge
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Nilsson, L. Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Metapopulation pollination in the deceptive orchid Anacamptis pyramidalis2007In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 25, no 3-4, p. 176-182Article in journal (Refereed)
    Abstract [en]

    Pollen dispersal between local plant populations within a range of 6 kin in a geographically defined metapopulation of the lepidopteran-pollinated deceptive orchid Anacamptis pyramidalis was studied on the island Oland in the Baltic Sea. Local A. pyramidalis populations were examined for pollinators, flowering individuals, and fruit set. Population sizes of pollen vector species were estimated using a mark-release-recapture technique. As pollen vectors, the burner moth Zygaena minos and the butterfly Aporia crataegi dominated. 205 out of 745 marked lepidopterans were pollinarium carriers. The proportion carriers of the total was considerably higher in Z. minos (50.3%), than in A. crataegi (21.5%) and nymphalidae (8.2%). Furthermore, Z minos moved much shorter distances than A. crataegi did, while no difference in potential pollen dispersal distances were found between males and females. The number of individual vectors recaptured in another local population of A. pyramidalis was low: A. crataegi (8) and Z minos (1). The ratio of pollinaria transferred to another local A. pyramidolis population compared to pollinaria remaining within the same local population was 1:41. This study highlights that pollen dispersal distances vary between pollen vector species.

  • 127.
    Löbel, Swantje
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Metapopulation and metacommunity processes, dispersal strategies and life-history trade-offs in epiphytes2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of this thesis was to increase knowledge about metapopulation and metacommunity processes in patchy, dynamic landscapes, using epiphytic bryophytes as a model system. Host trees and deciduous forest stands in the coniferous landscape are patchy, temporal and undergo changes in habitat quality during succession. Epiphytes must track this dynamic habitat network for their long-term survival. Community patterns at different spatial scales were explored and linked to regional metapopulation processes and local population dynamics.

    Spatial structuring in species richness both at a local and regional scale indicated stronger dispersal limitation but lower sensitivity to habitat quality in species with large asexual than in species with small sexual diaspores. In sexually dispersed species, a strong rescue effect was indicated by a bimodal frequency distribution of the species and by increasing local abundance with increasing patch connectivity. Present connectivity to other deciduous forest patches had positive effects on richness of asexually dispersed species, whereas richness of sexually dispersed species was instead related to the landscape connectivity 30 years ago. A study of local growth and reproduction suggested that this is caused by delayed sexual, but not asexual, reproduction. Habitat conditions affected the production of sporophytes, but not of asexual diaspores. No differences in either growth rates or competitive abilities among species with different dispersal and life-history strategies were found. In vitro experiments showed that establishment is higher from large asexual diaspores than from small sexual. Establishment of all diaspore types was limited by pH. There were indications of trade-offs between high germination and protonemal growth rates, desiccation tolerance and a rapid development of shoots from protonema.

    The results indicated that the epiphyte metacommunity is structured by two main trade-offs: dispersal distance (diaspore size) versus age at first reproduction, and dispersal distance versus sensitivity to habitat quality. Trade-offs in species traits may have evolved as a consequence of conflicting selection pressures imposed by habitat turnover, connectivity and irregular water supply rather than by species interactions. Syndromes of interrelated species traits imply that fairly small changes in habitat conditions can lead to distinct changes in metacommunity diversity: the results indicate that increasing distances among patches cause most harm to asexually dispersed species, whereas cuttings of forests of high age and quality as well as increasing patch dynamics are most harmful to sexually dispersed species.

    List of papers
    1. Species richness patterns and metapopulation processes evidence from epiphyte communities in boreo-nemoral forests
    Open this publication in new window or tab >>Species richness patterns and metapopulation processes evidence from epiphyte communities in boreo-nemoral forests
    2006 (English)In: Ecography, Vol. 29, p. 169-182Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-24126 (URN)
    Available from: 2007-02-03 Created: 2007-02-03 Last updated: 2019-02-01
    2. Metapopulation processes in epiphytes inferred from patterns of regional distribution and local abundance in fragmented forest landscapes
    Open this publication in new window or tab >>Metapopulation processes in epiphytes inferred from patterns of regional distribution and local abundance in fragmented forest landscapes
    2006 (English)In: Journal of Ecology, Vol. 94, p. 856-868Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-24128 (URN)
    Available from: 2007-02-03 Created: 2007-02-03 Last updated: 2019-02-01
    3. Mating system, reproduction mode and diaspore size affect metacommunity diversity
    Open this publication in new window or tab >>Mating system, reproduction mode and diaspore size affect metacommunity diversity
    2009 (English)In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 97, no 1, p. 176-185Article in journal (Refereed) Published
    Abstract [en]

    1. Metapopulation persistence and metacommunity diversity in patchy dynamic landscapes critically depend on efficient dispersal. Dispersal strategies could involve trade-offs that result in different species responses to habitat fragmentation, alteration in habitat quality and changes in landscape dynamics. 2. We studied spatial structuring in species richness of obligate epiphytic bryophytes in 135 deciduous forest patches in a largely coniferous landscape in Sweden. We tested the effects of forest patch size (0.01-15 ha), patch quality and present and historic connectivity (as revealed by air photographs) on species richness of species groups with different mating systems, reproduction modes and diaspore sizes. 3. Present connectivity to other deciduous forest patches had positive effects on richness of dioecious species with predominant asexual reproduction, whereas richness of monoecious species with predominant sexual reproduction was affected by historic connectivity only. The scale of spatial structuring in species richness increased with decreasing diaspore sizes. Forest patch quality affected richness of monoecious species reproducing sexually but not of dioecious species reproducing asexually. 4. Our results suggest shorter dispersal distances, but higher establishment rates, of large asexual diaspores than of small sexual ones. In monoecious species with sexual reproduction, it may take several decades from establishment to first spore production, and this may explain the strong effect of historic, but not present, forest patch connectivity on species richness of this group. This suggests a trade-off between dispersal distance and age at first reproduction, which may explain the parallel evolution of asexual reproduction and monoecism in species inhabiting patchy, transient habitats. 5. Synthesis. We conclude that dispersal success of metacommunity members is influenced both by species traits and habitat characteristics. In patch-tracking metacommunities, trade-offs in species traits may have evolved as a consequence of conflicting selection pressures imposed by habitat patchiness and dynamics. Syndromes of interrelated species traits imply that fairly small changes in habitat conditions may lead to distinct changes in metacommunity diversity: Species reproducing asexually may drastically decline with increasing distances among patches, whereas sexually reproducing species may decline with increasing patch dynamics.

    Keywords
    asexual reproduction, bryophytes, dispersal strategies, epiphytes, habitat fragmentation, landscape dynamics, life-history trade-offs, metapopulation, patch-tracking, species richness
    National Category
    Biological Sciences
    Research subject
    Ecological Botany
    Identifiers
    urn:nbn:se:uu:diva-107313 (URN)10.1111/j.1365-2745.2008.01459.x (DOI)000261684400020 ()
    Available from: 2009-08-05 Created: 2009-08-05 Last updated: 2019-02-01Bibliographically approved
    4. Dispersal and life-history strategies in epiphyte metacommunities: alternative solutions to survival in patchy, dynamic landscapes
    Open this publication in new window or tab >>Dispersal and life-history strategies in epiphyte metacommunities: alternative solutions to survival in patchy, dynamic landscapes
    2009 (English)In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 161, no 3, p. 569-579Article in journal (Refereed) Published
    Abstract [en]

    Host trees for obligate epiphytes are dynamic patches that emerge, grow and fall, and metacommunity diversity critically depends on efficient dispersal. Even though species that disperse by large asexual diaspores are strongly dispersal-limited, asexual dispersal is common. The stronger dispersal limitation of asexually reproducing species compared to species reproducing sexually via small spores may be compensated by higher growth rates, lower sensitivity to habitat conditions, higher competitive ability or younger reproductive age.

    We compared growth and reproduction of different groups of epiphytic bryophytes with contrasting dispersal (asexual vs sexual) and life-history strategies (colonists, short- and long-lived shuttle species, perennial stayers) in an old-growth forest stand in the boreo-nemoral region in Eastern Sweden.

    No differences were seen in relative growth rates between asexual and sexual species. Long-lived shuttles had lower growth rates than colonists and perennial stayers. Most groups grew best at intermediate bark pH. Interactions with other epiphytes had a small, often positive effect on growth. Neither differences in sensitivity of growth to habitat conditions nor differences in competitive abilities among species groups were found. Habitat conditions, however, influenced the production of sporophytes, but not of asexual diaspores. Presence of sporophytes negatively affected growth, whereas presence of asexual diaspores did not. Sexual species had to reach a certain colony size before starting to reproduce, whereas no such treshold existed for asexual reproduction.

    The results indicate that the epiphyte metacommunity is structured by two main trade-offs: dispersal distance vs reproductive age, and dispersal distance vs sensitivity to habitat quality. There seems to be a trade-off between growth and sexual reproduction, but not asexual. Trade-offs in species traits may be shaped by conflicting selection pressures imposed by habitat turnover and connectivity rather than by species interactions.

    Keywords
    Growth, Local processes, Metapopulation, Reproduction, Trade-offs
    National Category
    Biological Sciences
    Research subject
    Ecological Botany
    Identifiers
    urn:nbn:se:uu:diva-107314 (URN)10.1007/s00442-009-1402-1 (DOI)000269010300012 ()
    Available from: 2009-08-05 Created: 2009-08-05 Last updated: 2019-02-01Bibliographically approved
    5. Trade-offs and habitat constraints in the establishment of epiphytic bryophytes
    Open this publication in new window or tab >>Trade-offs and habitat constraints in the establishment of epiphytic bryophytes
    2010 (English)In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 24, no 4, p. 887-897Article in journal (Refereed) Published
    Abstract [en]

    1. Diversity of patch-tracking epiphyte metacommunities depends on successful colonization of new habitats. Habitat constraints and critical stages in the establishment have gained little attention in metacommunity studies, but a trade-off between dispersal ability and establishment rate is often assumed. This assumption remains largely untested, and alternative dispersal and reproductive strategies offer several trade-offs to be explored.

    2. We used in vitro experiments to identify critical stages in the establishment of obligate epiphytic bryophytes with contrasting dispersal strategies [sexual via small (< 20 mu m) or large (> 20 mu m) spores, asexual via gemmae or gemmae-like branchlets], and to identify habitat constraints of diaspore establishment and trade-offs among species traits.

    3. Across all stages of the establishment process, large asexual diaspores performed better than small sexual ones. Asexual species also had a higher ability to establish from fragments than sexual species. Germination of all diaspore types was limited by pH with highest germination rates at intermediate pH. Large moss spores showed a higher desiccation tolerance than small ones, but lower germination and protonemal growth rates. Liverwort spores had the lowest desiccation tolerance, germination and protonemal growth rates, but rapidly developed gametophytic shoots once they had germinated.

    4. Combining the results with earlier studies on dispersal distances in epiphytes, our study demonstrated a trade-off between dispersal distance and establishment ability, which may be central for the evolution of asexual dispersal in epiphytes. The evolution of spore size may additionally involve trade-offs between high germination and protonemal growth rates, desiccation tolerance, and a rapid development from protonema to shoots. We suggest that trade-offs in epiphytes are shaped by conflicting selection pressures imposed by habitat patchiness, landscape dynamics and irregular water supply.

    Keywords
    desiccation, germination, life-history trade-offs, metacommunity, pH, patch-tracking, protonema, reproductive strategies
    National Category
    Biological Sciences
    Research subject
    Ecological Botany
    Identifiers
    urn:nbn:se:uu:diva-107315 (URN)10.1111/j.1365-2435.2010.01705.x (DOI)000279837700022 ()
    Note
    Part of PhD-thesis which will be defended the 26th of September 2009Available from: 2009-08-05 Created: 2009-08-05 Last updated: 2019-02-01Bibliographically approved
  • 128.
    Löbel, Swantje
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Dengler, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Dry grassland communities on southern Öland: phytosociology, ecology, and diversity2008In: Acta Phytogeographica Suecica, ISSN 0084-5914, Vol. 88, p. 13-31Article in journal (Refereed)
    Abstract [en]

    We studied dry grassland vegetation on southern Öland, both within and outside the Great Alvar, using the Braun-Blanquet approach. We were able to distinguish 15 associations or equivalent units belonging to three major syntaxa. Dry grasslands on sandy soils (class Koelerio-Corynephoretea; subclass Koelerio-Corynephorenea) occurred along the east and west coasts. Weathered rock and outcrop communities (class Koelerio-Corynephoretea; subclass Sedo-Scleranthenea) inhabited shallow skeletal soils, mainly on the Great Alvar. Semi-dry basiphilous grasslands of the class Festuco-Brometea occurred on moraine soils, which were the least extreme in terms of soil moisture and nutrient availability. Whereas the first category comprises impoverished variants of widely distributed syntaxa, all Sedo-Scleranthenea and Festuco-Brometea communities lack direct counterparts in central Europe. The alvar communities proved to be floristically well separated from the others. Species density on 4 m2 was highest in the Sedo-Scleranthenea (that of the Gypsophilo fastigiatae-Globularietum vulgaris with 80 taxa being one of the highest known), intermediate in the Festuco-Brometea, and lowest in the Koelerio-Corynephorenea. Harsh and variable conditions, small plant sizes, and a large local species pool are considered possible causes.

  • 129.
    Löbel, Swantje
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Dengler, J.
    Hobohm, C.
    Species richness of vascular plants, bryophytes and lichens in dry grasslands: The effects of environment, landscape structure and competition2006In: Folia Geobotanica, ISSN 1211-9520, E-ISSN 1874-9348, Vol. 41, no 4, p. 377-393Article in journal (Refereed)
    Abstract [en]

    We studied the relative importance of local habitat conditions and landscape structure for species richness of vascular plants, bryophytes and lichens in dry grasslands on the Baltic island of Oland (Sweden). In addition, we tested whether relationships between species richness and vegetation cover indicate that competition within and between the studied taxonomic groups is important. We recorded species numbers of vascular plants, bryophytes and lichens in 4 m(2) plots (n = 452), distributed over dry grassland patches differing in size and degree of isolation. Structural and environmental data were collected for each plot. We tested effects of local environmental conditions, landscape structure and vegetation cover on species richness using generalized linear mixed models. Different environmental variables explained species richness of vascular plants, bryophytes and lichens. Environmental effects, particularly soil pH, were more important than landscape structure. Interaction effects of soil pH with other environmental variables were significant in vascular plants. Plot heterogeneity enhanced species richness. Size and degree of isolation of dry grassland patches significantly affected bryophyte and lichen species richness, but not that of vascular plants. We observed negative relationships between bryophyte and lichen species richness and the cover of vascular plants. To conclude, effects of single environmental variables on species richness depend both on the taxonomic group and on the combination of environmental factors on a whole. Dispersal limitation in bryophytes and lichens confined to dry grasslands may be more common than is often assumed. Our study further suggests that competition between vascular plants and cryptogams is rather asymmetric.

  • 130.
    Löbel, Swantje
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Snäll, Tord
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Mating system, reproduction mode and diaspore size affect metacommunity diversity2009In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 97, no 1, p. 176-185Article in journal (Refereed)
    Abstract [en]

    1. Metapopulation persistence and metacommunity diversity in patchy dynamic landscapes critically depend on efficient dispersal. Dispersal strategies could involve trade-offs that result in different species responses to habitat fragmentation, alteration in habitat quality and changes in landscape dynamics. 2. We studied spatial structuring in species richness of obligate epiphytic bryophytes in 135 deciduous forest patches in a largely coniferous landscape in Sweden. We tested the effects of forest patch size (0.01-15 ha), patch quality and present and historic connectivity (as revealed by air photographs) on species richness of species groups with different mating systems, reproduction modes and diaspore sizes. 3. Present connectivity to other deciduous forest patches had positive effects on richness of dioecious species with predominant asexual reproduction, whereas richness of monoecious species with predominant sexual reproduction was affected by historic connectivity only. The scale of spatial structuring in species richness increased with decreasing diaspore sizes. Forest patch quality affected richness of monoecious species reproducing sexually but not of dioecious species reproducing asexually. 4. Our results suggest shorter dispersal distances, but higher establishment rates, of large asexual diaspores than of small sexual ones. In monoecious species with sexual reproduction, it may take several decades from establishment to first spore production, and this may explain the strong effect of historic, but not present, forest patch connectivity on species richness of this group. This suggests a trade-off between dispersal distance and age at first reproduction, which may explain the parallel evolution of asexual reproduction and monoecism in species inhabiting patchy, transient habitats. 5. Synthesis. We conclude that dispersal success of metacommunity members is influenced both by species traits and habitat characteristics. In patch-tracking metacommunities, trade-offs in species traits may have evolved as a consequence of conflicting selection pressures imposed by habitat patchiness and dynamics. Syndromes of interrelated species traits imply that fairly small changes in habitat conditions may lead to distinct changes in metacommunity diversity: Species reproducing asexually may drastically decline with increasing distances among patches, whereas sexually reproducing species may decline with increasing patch dynamics.

  • 131.
    Löbel, Swantje
    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.
    Snäll, Tord
    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.
    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.
    Metapopulation processes in epiphytes inferred from patterns of regional distribution and local abundance in fragmented forest landscapes2006In: Journal of Ecology, Vol. 94, p. 856-868Article in journal (Refereed)
  • 132.
    Löbel, Swantje
    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.
    Snäll, Tord
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Rydin, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Species richness patterns and metapopulation processes evidence from epiphyte communities in boreo-nemoral forests2006In: Ecography, Vol. 29, p. 169-182Article in journal (Refereed)
  • 133.
    Løe, Geir
    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.
    Söderström, L
    Regeneration of Herbertus S.F.Gray fragments in the laboratory2001In: Lindbergia, Vol. 26, p. 3-7Article in journal (Refereed)
  • 134.
    Løe, Geir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Toräng, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Gauldeul, Myriam
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Trichome production and spatiotemporal variation in herbivory in the perennial herb Arabidopsis lyrata2007In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 116, no 1, p. 134-142Article in journal (Refereed)
    Abstract [en]

    Allocation theory suggests that the optimal level of resistance against herbivores should vary with the risk of herbivory if allocation to resistance is costly. The perennial herb Arabidopsis lyrata has a genetically based polymorphism for- trichome production and occurs in a glabrous and a trichome-producing form. Leaf trichomes (hairs) can protect plants against insect herbivores, and may increase tolerance to drought and UV-radiation. To examine the functional significance of trichome production, we documented the frequency of glabrous plants and damage by insect herbivores in 30 A. lyrata populations in Sweden and Norway. The proportion of glabrous plants ranged from 0.10 to 0.71 (median = 0.44) in polymorphic populations; 7 of 12 populations in Norway and 14 of 18 populations in Sweden were monomorphic glabrous, i.e. with fewer than 5% trichome-producing plants. The mean proportion of the leaf area removed by herbivores varied substantially among populations and years. With few exceptions, glabrous plants were more damaged than trichome-producing plants in polymorphic populations. The intensity of herbivory quantified as the mean damage to glabrous plants tended to be higher in polymorphic populations than in populations monomorphic for the glabrous morph and was higher in Sweden than in Norway. In Norway, both the magnitude of herbivore damage and the frequency of trichome-producing plants tended to decrease with increasing altitude. The results indicate that leaf trichomes contribute to resistance against herbivorous insects in A. lyrata, and suggest that herbivore-mediated selection contributes to the maintenance of the polymorphism in trichome production.

  • 135. Maad, J
    et al.
    Alexandersson, Ronny
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Variable selection in Platanthera bifolia (Orchidaceae): phenotypic selection differed between sex functions in a drought year2004In: Journal of Evolutionary Biology, Vol. 17, p. 642-650Article in journal (Refereed)
  • 136.
    Maad, Johanne
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Department of Evolution, Genomics and Systematics. Biology, Department of Ecology and Evolution, Plant Ecology. Systematisk Botanik.
    Nilsson, L. Anders
    Department of Evolutionary Biology. Biology, Department of Ecology and Evolution, Plant Ecology.
    On the mechanism of floral shifts in speciation: gained pollination efficiency from tongue- to eye-attachment of pollinia in Platanthera (Orchidaceae)2004In: Biological Journal of the Linnean Society, Vol. 83, no 4, p. 481-495Article in journal (Refereed)
    Abstract [en]

    This work explores the mechanism of floral shifts that may result in speciation. The model organisms chosen were the moth-pollinated pollinator-limited orchid species Platanthera bifolia and P. chlorantha. P. bifolia exhibits tongue-attachment of pollinia on pollinators, a character state that has been found previously to be ancestral. The close relative P. chlorantha exhibits the derived state of eye-attachment of pollinia on pollinators. We reasoned that differences between the species in pollination efficiency could give insights into the mechanism of floral shifts and thus cladogenesis. Four populations per species were investigated. In three populations, where the species were growing intermixed and were sharing pollinators, there was significant difference in the pollen export and import efficiency per visit-night (night with pollen export and/or import) between the two species. P. bifolia exported pollinia more efficiently but imported pollen less efficiently than did P. chlorantha. Pollen import was 1.74 times faster in P. chlorantha (eye-attachment) than it was in P. bifolia (tongue-attachment). P. chlorantha had a lower risk of interference between pollen import and export. An increase in fitness through greater speed and efficiency of pollen import due to an enlargement of the stigmatic surface and a reduction in the risk of sexual interference may therefore be mechanisms of the floral shift from tongue- to eye-attachment of pollinia on pollinators. 

  • 137.
    Maad, Johanne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Sundberg, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Stolpe, Per
    Jonsell, Lena
    Floraförändringar i Uppland under 1900-talet – en analys från Projekt Upplands flora2009In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 103, no 2, p. 67-104Article in journal (Refereed)
  • 138.
    Malmer, Nils
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. PLANT ECOLGY.
    Albinsson, C
    Svensson, Brita
    Department of Ecology and Evolution, Plant Ecology.
    Wallén, B
    Interferences between Sphagnum and vascular plants: effects on plant community structure and peat formation2003In: Oikos, Vol. 100, p. 469-482Article in journal (Refereed)
  • 139.
    Manktelow, Mariette
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Linnés dokumentation av växterna på Hammarby2001In: Svenska Linnésällskapets Årsbok, Vol. 2000-2001, p. 137-141Article in journal (Refereed)
  • 140. Mitlacher, K
    et al.
    Poschlod, P
    Rosén, Ejvind
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Bakker, JP
    Restoration of wooded meadows: a comparative analysis along a chronosequence on Öland (Sweden)2002In: Journal of Applied Vegetation Science, Vol. 5, p. 63-73Article in journal (Refereed)
  • 141.
    Munkert, Helena C.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Sexual and vegetative regeneration of three leguminous tree species in South African savannas2009In: South African Journal of Botany, ISSN 0254-6299, E-ISSN 1727-9321, Vol. 75, no 3, p. 606-610Article in journal (Refereed)
    Abstract [en]

    The legume trees Dichrostachys cinerea, Acacia karroo and Acacia nilotica are encroaching a number of African savannas. I quantified the extent to which these species regenerated by seeds and root suckers respectively, and how land management affects the mode of regeneration. I used transects at three sites inside the Hluhluwe-iMfolozi Park and at three sites in adjacent villages outside the park to score all individuals shorter than 20 cm. I also excavated the roots to determine whether the plant was a gamete or a ramet connected to an established mother tree. I found D. cinerea regenerated to equal extent vegetatively and sexually, while A. karroo and A. nilotica mainly regenerated sexually. The present results suggest that the capacity of sexual regeneration of trees is important to consider in future management of bush encroachment in southern African savannas.

  • 142.
    Mälson, Kalle
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Backéus, Ingvar
    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.
    Long-term effects of drainage and initial effects of hydrological restoration on rich fen vegetation2008In: Applied Vegetation Science, ISSN 1402-2001, E-ISSN 1654-109X, Vol. 11, no 1, p. 99-106Article in journal (Refereed)
    Abstract [en]

    Questions: What vegetational changes does a boreal rich fen (alkaline fen) undergo during a time period of 24 years after drainage? How is plant species richness affected, and what are the changes in composition of ecological groups of species? Is it possible to recover parts of the original flora by rewetting the rich fen? Which are the initial vegetation changes in the flora after rewetting? What are the major challenges for restoration of rich fen flora after rewetting? Location: Eastern central Sweden, southern boreal vegetational zone. Previously rich fen site, drained for forestry purposes during 1978-1979. The site was hydrologically restored (rewetted) in 2002. Method: Annual vegetation survey in permanent plots during a period of 28 years. Results: There were three successional stages in the vegetational changes. In the first stage there was a rapid (< 5 years) loss of rich fen bryophytes. The second step was an increase of sedges and early successional bryophytes, which was followed by an increase of a few emerging dominants, such as Molinia caerulea, Betula pubescens and Sphagnum spp. After rewetting, there are indications of vegetation recovery, albeit at slow rates. Depending on, for instance, initial species composition different routes of vegetation change were observed in the flora after drainage, although after 24 years, species composition became more homogenous and dominated by a few species with high cover. Conclusion: Major changes have occurred after changes in the hydrology (drainage and rewetting) with a severe impact on the biodiversity among vascular plants and bryophytes. Several rich fen bryophytes respond quickly to the changes in water level (in contrast to vascular plants). The recovery after rewetting towards the original rich fen vegetation is slow, as delayed by substrate degradation, dispersal limitation and presence of dominant species.

  • 143.
    Mälson, Kalle
    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.
    Competitive hierarchy, but no competitive exclusions in experiments with rich fen bryophytes2009In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820, Vol. 31, no Part 1, p. 41-45Article in journal (Refereed)
    Abstract [en]

    Competitive exclusion among species with high niche overlap has been questioned by plant ecologists over the last decades. In this study, we used a greenhouse experiment to test the role of competition for community dynamics and composition among bryophytes in boreal rich (calcareous) fens. We evaluate the rate and direction of competition between three of the most common bryophytes in these wetlands, Campylium stellatum, Scorpidium cossonii and Scorpidium scorpioides. A pair-wise experimental setup with equal amounts of initial plant material of the species was used and the experiment continued for two years. To assess the competitive outcome we measured the area expansion of one species into the part of the experimental containers covered by its competitor, and the height growth of each species. Differences were observed between tested species for total spatial expansion into the area of its competitor. C. stellatum and S. cossonii showed similar total spatial expansion, while S. scorpioides showed very low spatial expansion. The spatial expansion also depended on the identity of the other species in the combination. All three pair-wise interactions were strongly asymmetric, and in qualitative terms a competitive hierarchy could be established. However, this did not lead to competitive exclusions, even though the experimental containers were small and the two years of continuous growth in the greenhouse would correspond to several years of growth under field conditions. The results suggest that in the natural habitat, where interactions are further weakened by microtopographic niche separation and interrupted by fine-scale disturbances, competitive exclusions are probably rare, if they occur at all.

  • 144.
    Mälson, Kalle
    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.
    The regeneration capabilities of bryophytes in rich fen restoration2007In: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 135, no 3, p. 435-442Article in journal (Refereed)
    Abstract [en]

    Biodiversity in wetland habitats is strongly affected by drainage. In Sweden, rich fens (alkaline fens) have been particularly affected by drainage campaigns for forestry and conversion to agricultural land. Fragmentation of the landscape, invasion of tall vascular plants as well as Polytrichum and Sphagnum mosses and substrate degradation all lead to reduced plant diversity.

    We evaluated the recolonization potential of four characteristic rich fen bryophyte species that use to decrease rapidly after drainage (Scorpidium scorpioides, Scorpidium cossonii, Pseudocalliergon trifarium and Campylium stellatum) by performing transplantation studies with gametophyte fragments in recently hydrologically restored rich fens. In greenhouse and field experiments 1 cm fragments of all four species had a high survival rate and established well, especially after surface liming of the peat. A protective cover increased the colonization success and the growth potential of the added fragments. Even small alterations of the water level (5 cm) resulted in differences in biomass growth of the fragments of S. cossonii and C. stellatum. Our results show that it is possible to reintroduce bryophyte species lost after drainage using gametophyte fragments as propagules, and that these techniques seem feasible for a number of characteristic rich fen bryophytes. These findings will be of importance when methods for practical restoration of rich fens are developed.

  • 145.
    Méndez, M. and Traveset, A.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. PLANT ECOLGY.
    Sexual allocation in single-flowered hermaphroditic individuals in relation to plant and flower size2003In: Oecologia, Vol. 137, p. 69-75.Article in journal (Refereed)
  • 146.
    Méndez, M.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. PLANT ECOLGY.
    Karlsson, P. S.
    Between-population variation in size-dependent reproduction and reproductive allocation in Pinguicula vulgaris (Lentibulariaceae) and its environmental correlates2003In: Oikos, Vol. 104, p. 59-70.Article in journal (Refereed)
  • 147.
    Méndez, Marcos
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. Växtekologi.
    Sexual mass allocation in species with inflorescences as pollination units: a comparison between Arum italicum and Arisaema (Araceae)2001In: American Journal of Botany, Vol. 88, p. 1781-1785Article in journal (Refereed)
  • 148.
    Méndez, Marcos
    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.
    Díaz, A
    Flowering dynamics in Arum italicum (Araceae)2001In: American Journal of Botany, Vol. 88, p. 1774-1780Article in journal (Refereed)
  • 149. Méndez, Marcos
    et al.
    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.
    Nutrient stoichiometry in Pinguicula vulgaris: nutrient availability, plant size, and reproductive status2005In: Ecology, Vol. 86, p. 982-991Article in journal (Refereed)
  • 150.
    Nilsson, Emil
    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.
    Blomman som kunde gjort Linné till Darwin2007In: Forskning och framsteg, no 1, p. 26-31Article in journal (Other (popular scientific, debate etc.))
123456 101 - 150 of 259
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