uu.seUppsala University Publications
Change search
Refine search result
1 - 19 of 19
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Bahram, Mohammad
    et al.
    Kõljalg, Urmas
    Courty, Pierre-Emmanuel
    Diédhiou, Abdala G.
    Kjøller, Rasmus
    Põlme, Sergei
    Ryberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Systematic Biology.
    Veldre, Vilmar
    Tedersoo, Leho
    The distance decay of similarity in communities of ectomycorrhizal fungi in different ecosystems and scales2013In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 101, no 5, p. 1335-1344Article in journal (Refereed)
    Abstract [en]

    Despite recent advances in understanding community ecology of ectomycorrhizal fungi, little is known about their spatial patterning and the underlying mechanisms driving these patterns across different ecosystems. * This meta-study aimed to elucidate the scale, rate and causes of spatial structure of ectomycorrhizal fungal communities in different ecosystems by analysing 16 and 55 sites at the local and global scales, respectively. We examined the distance decay of similarity relationship in species- and phylogenetic lineage-based communities in relation to sampling and environmental variables. * Tropical ectomycorrhizal fungal communities exhibited stronger distance-decay patterns compared to non-tropical communities. Distance from the equator and sampling area were the main determinants of the extent of distance decay in fungal communities. The rate of distance decay was negatively related to host density at the local scale. At the global scale, lineage-level community similarity decayed faster with latitude than with longitude. * Synthesis. Spatial processes play a stronger role and over a greater scale in structuring local communities of ectomycorrhizal fungi than previously anticipated, particularly in ecosystems with greater vegetation age and closer to the equator. Greater rate of distance decay occurs in ecosystems with lower host density that may stem from increasing dispersal and establishment limitation. The relatively strong latitude effect on distance decay of lineage-level community similarity suggests that climate affects large-scale spatial processes and may cause phylogenetic clustering of ectomycorrhizal fungi at the global scale.

  • 2.
    Bengtsson, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Ecological Botany.
    Fumana procumbens on Öland: population dynamics of a disjunct species at the northern limit of its range.1993In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 81, p. 745-758Article in journal (Refereed)
  • 3. Bragazza, Luca
    et al.
    Gerdol, Renato
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology.
    Effects of mineral and nutrient input on mire bio-geochemistry in two geographical regions2003In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 91, no 3, p. 417-426Article in journal (Refereed)
    Abstract [en]

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

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

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

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

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

  • 4. Brooker, Rob W.
    et al.
    Carlsson, Bengt Å.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Callaghan, Terry V.
    Carex bigelowii Torrey ex Schweinitz (C. rigida Good., non Schrank; C. hyperborea Drejer)2001In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 89, no 6, p. 1072-1095Article in journal (Refereed)
  • 5.
    Cornelissen, C
    et al.
    Vrije Univ Amsterdam.
    Callaghan, V
    Alatalo, Juha
    Göteborgs Universitet.
    Michelsen, A
    Graglia, E
    Hartley, E
    Hik, S
    Hobbie, E
    Press, C
    Robinson, H
    Henry, R
    Shaver, R
    Phoenix, K
    Jones, G
    Jonasson, S
    Chapin, S
    Molau, U
    Neill, C
    Lee, A
    Melillo, M
    Sveinbjornsson, B
    Aerts, R
    Global change and arctic ecosystems: is lichen decline a function of increases in vascular plant biomass?2001In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 89, no 6, p. 984-994Article in journal (Refereed)
    Abstract [en]

    1 Macrolichens are important for the functioning and biodiversity of cold northern ecosystems and their reindeer-based cultures and economics. 2 We hypothesized that, in climatically milder parts of the Arctic, where ecosystems have relatively dense plant canopies, climate warming and/or increased nutrient availability leads to decline in macrolichen abundance as a function of increased abundance of vascular plants. In more open high-arctic or arctic-alpine plant communities such a relationship should be absent. To test this, we synthesized cross-continental arctic vegetation data from ecosystem manipulation experiments simulating mostly warming and increased nutrient availability, and compared these with similar data from natural environmental gradients. 3 Regressions between abundance or biomass of macrolichens and vascular plants were consistently negative across the subarctic and mid-arctic experimental studies. Such a pattern did not emerge in the coldest high-arctic or arctic-alpine sites. The slopes of the negative regressions increased across 10 sites as the climate became milder (as indicated by a simple climatic index) or the vegetation denser (greater site above-ground biomass). 4 Seven natural vegetation gradients in the lower-altitude sub- and mid-arctic zone confirmed the patterns seen in the experimental studies, showing consistent negative relationships between abundance of macrolichens and vascular plants. 5 We conclude that the data supported the hypothesis. Macrolichens in climatically milder arctic ecosystems may decline if and where global changes cause vascular plants to increase in abundance. 6 However, a refining of our findings is needed, for instance by integrating other abiotic and biotic effects such as reindeer grazing feedback on the balance between vascular plants and lichens.

  • 6.
    Ehrlen, Johan
    et al.
    Stockholm Univ, Dept Ecol Environm & Plant Sci, SE-10691 Stockholm, Sweden..
    Morris, William F.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics. Duke Univ, Dept Biol, Box 90338, Durham, NC 27708 USA..
    von Euler, Tove
    Stockholm Univ, Dept Ecol Environm & Plant Sci, SE-10691 Stockholm, Sweden..
    Dahlgren, Johan P.
    Univ So Denmark, Dept Biol, Campusvej 55, DK-5230 Odense M, Denmark.;Univ So Denmark, Max Planck Odense Ctr Biodemog Aging, Campusvej 55, DK-5230 Odense M, Denmark..
    Advancing environmentally explicit structured population models of plants2016In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 104, no 2, p. 292-305Article in journal (Refereed)
    Abstract [en]

    The relationship between the performance of individuals and the surrounding environment is fundamental in ecology and evolutionary biology. Assessing how abiotic and biotic environmental factors influence demographic processes is necessary to understand and predict population dynamics, as well as species distributions and abundances. We searched the literature for studies that have linked abiotic and biotic environmental factors to vital rates and, using structured demographic models, population growth rates of plants. We found 136 studies that had examined the environmental drivers of plant demography. The number of studies has been increasing rapidly in recent years. Based on the reviewed studies, we identify and discuss several major gaps in our knowledge of environmentally driven demography of plants. We argue that some drivers may have been underexplored and that the full potential of spatially and temporally replicated studies may not have been realized. We also stress the need to employ relevant statistical methods and experiments to correctly identify drivers. Moreover, assessments of the relationship between drivers and vital rates need to consider interactive, nonlinear and indirect effects, as well as effects of intraspecific density dependence.Synthesis. Much progress has already been made by using structured population models to link the performance of individuals to the surrounding environment. However, by improving the design and analyses of future studies, we can substantially increase our ability to predict changes in plant population dynamics, abundances and distributions in response to changes in specific environmental drivers. Future environmentally explicit demographic models should also address how genetic changes prompted by selection imposed by environmental changes will alter population trajectories in the face of continued environmental change and investigate the reciprocal feedback between plants and their biotic drivers.

  • 7. Favre, Adrien
    et al.
    Karrenberg, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Stress tolerance in closely related species and their first-generation hybrids: a case study of Silene2011In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 99, no 6, p. 1415-1423Article in journal (Refereed)
    Abstract [en]

    1. Hybridization is common in natural plant populations. Trait expression and ecological performance of hybrids determine the consequences of hybridization such as the degree and direction of gene flow or the generation of phenotypic novelty.

    2. We investigated responses to shade and drought stress in crosses within the naturally hybridizing campions Silene dioica and S. latifolia and reciprocal crosses between them. We collected data on fitness proxies and on leaf and root traits in a 2-year greenhouse experiment.

    3. Responses to drought stress did not differ between cross types. Shade stress, in contrast, led to a reduced flowering incidence in S. dioica but not in S. latifolia. Rapid flowering under stress conditions in S. latifolia could be an adaptation to disturbance in its habitat, whereas a delay of reproduction might be adaptive in the more predictable environment of S. dioica.

    4. Hybrids exhibited intermediate, parental-like and transgressive trait expression. Both hybrid cross types were similar to S. latifolia in terms of biomass production possibly because of dominance of S. latifolia alleles or heterosis. Hybrids further had a strongly reduced flowering incidence under shade stress as did S. dioica, suggesting dominance of S. dioica alleles for flower induction. Under shade stress, both hybrid cross types produced much larger leaves than either of the two species suggesting that epigenetic interactions are disturbed. Reciprocal hybrids did not differ in fitness; however, maternal effects were observed for root cross-sectional area and mass per male flower, possibly supporting asymmetric gene flow in natural populations.

    5.Synthesis. Silene latifolia and S. dioica responded to stress with differences in life history rather than in growth. Our results further suggest that different modes of gene action are responsible for the specific combination of intermediate, parental-like and transgressive traits observed in first-generation hybrids that may limit their performance and thus gene flow between the species.

  • 8.
    Grandin, Ulf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecological Botany.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecological Botany.
    Attributes of the seed bank after a century of primary succession on islands in Lake Hjalmaren, Sweden1998In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 86, no 2, p. 293-303Article in journal (Refereed)
    Abstract [en]

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

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

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

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

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

  • 9. Kapfer, Jutta
    et al.
    Grytnes, John-Arvid
    Gunnarsson, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Birks, H. John B.
    Fine-scale changes in vegetation composition in a boreal mire over 50 years2011In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 99, no 5, p. 1179-1189Article in journal (Refereed)
    Abstract [en]

    1. In the face of a rapidly changing environment, long-term studies provide important insights into patterns of vegetation and processes of change, but long-term studies are rare for many ecosystems. 2. We studied recent vegetation changes at a fine scale in a Sphagnum-dominated bog in south Sweden by resurveying part of the bog 54 years after the original phytosociological survey. We used an indirect approach to identify changes in vegetation composition in relation to environment because of a lack of permanent sampling units. By applying a weighted averaging technique, we calculated relative changes in species optimum values for different environmental gradients as represented by indicator values for light, temperature, pH, moisture and nutrients. 3. Species composition of the mire vegetation has changed significantly over the past five decades, as indicated by significant changes in species frequencies and species optima for the gradients examined. Species with lower indicator values for moisture and light and higher indicator values for nutrients have become more frequent on the mire. In particular, species of trees and dwarf shrubs increased in frequency, whereas typical mire species decreased (e. g. Trichophorum cespitosum (L.) Hartm.) or disappeared from the study site (e. g. Scheuchzeria palustris L.). 4. Synthesis. Composition of the mire vegetation is found to be dynamic at different temporal and spatial scales. Increased air temperature and nutrient availability in south Sweden over the past few decades may have augmented productivity (e. g. tree growth), resulting in drier and shadier conditions for several species. This study successfully demonstrated the applicability of an indirect approach for detecting long-term vegetation change at a fine scale. This approach is an effective way of using historic and modern phytosociological data sets to detect vegetation and environmental change through time.

  • 10. Liess, Antonia
    et al.
    Lange, Katharina
    Schulz, Friederike
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution.
    Piggott, Jeremy J.
    Matthaei, Christoph D.
    Townsend, Colin R.
    Light, nutrients and grazing interact to determine diatom species richness via changes to productivity, nutrient state and grazer activity2009In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 97, no 2, p. 326-336Article in journal (Refereed)
    Abstract [en]

    1. Productivity and grazing pressure interact in determining autotroph diversity, because high productivity increases the capability of a plant community to compensate for grazing losses. However, further factors may play a role in shaping diversity, including primary producer nutrient stoichiometry and grazer activity. 2. Our study focuses on the interactions between light, nutrients and grazing in determining species richness and evenness of stream diatoms. By measuring primary producer productivity and nutrient content as well as grazer activity, we attempt to disentangle the different pathways by which the three factors affect diatom species richness and evenness. 3. We hypothesized that high light intensities and nutrient addition would increase species richness by increasing primary productivity and that higher levels of light and nutrients would compensate for negative grazer effects on species richness of primary producers. We also hypothesized that high light intensities would decrease the nutrient content of primary producers, especially when nutrients are limiting, whereas nutrient addition would increase primary producer nutrient content. Last, in addition to changing primary producer nutrient content, light and nutrients would also change grazer activity, thus modifying the interactions between light, nutrients and grazing. 4. We used periphyton and gastropod grazers in an experiment with circular stream channels with four nutrient, two light and four grazing levels to determine individual and combined effects on benthic diatom richness and evenness. After 3 weeks, we determined algal biomass, periphyton nutrient content, diatom species richness and evenness as well as grazer activity. 5. Our results showed that light and nutrients increased species richness and primary producer productivity and nutrient content. Grazing decreased species richness but only at low light levels, possibly because high light levels reduced grazer activity. Evenness was not affected by any single factor alone, but was influenced by nutrient-light and grazing-light interactions. 6. Synthesis. Light, nutrients and grazing interacted in determining primary producer species richness. Their effects were mainly mediated through changes in productivity but primary producer nutrient content and grazer activity also played important roles.

  • 11.
    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.

  • 12. Mitchell, E. A. D
    et al.
    Buttler, A
    Grosvernier, P
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Siegenthaler, A.
    Gobat, J.-M.
    Contrasted effects of increased N and CO2 supply on two keystone species in peatland restoration and implications for global change2002In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 90, no 3, p. 529-533Article in journal (Refereed)
    Abstract [en]

    1  Significant areas of temperate bogs have been damaged by peat harvesting but may regenerate. These secondary mires, if well managed, may act as strong C sinks, regulate hydrology and buffer regional climate.2 The potential effects of bog regeneration will, however, depend on the successful establishment of the principal peat formers –Sphagnum mosses. The influence of hydrology and microclimate on Sphagnum re-growth is well studied but effects of elevated CO2 and N deposition are not known.3 We carried out two in-situ experiments in a cutover bog during three growing seasons in which we raised either CO2 (to 560 p.p.m.) or N (by adding NH4NO3, 3 g m−2 year−1). The two treatments had contrasting effects on competition between the initial coloniser Polytrichum strictum (favoured by high N) and the later coloniser Sphagnum fallax (favoured by high CO2).

    4  Such changes may have important consequences for bog regeneration and hence for carbon sequestration in cutover bogs, with potential feedback on regional hydrological and climatic processes.

  • 13.
    Moor, Helen
    et al.
    Stockholm Univ, Stockholm Resilience Ctr, Kraftriket 2B, SE-10691 Stockholm, Sweden.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Hylander, Kristoffer
    Department of Ecology, Environment and Plant Sciences, Stockholm University, , Stockholm, Sweden.
    Nilsson, Mats B
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, , Umeå, Sweden.
    Lindborg, Regina
    Department of Physical Geography, Stockholm University, , Stockholm, Sweden.
    Norberg, Jon
    Stockholm Resilience Centre, Stockholm University, , Stockholm, Sweden.
    Towards a trait-based ecology of wetland vegetation2017In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 105, no 6, p. 1623-1635Article, review/survey (Refereed)
    Abstract [en]

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

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

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

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

  • 14. Scofield, Douglas G.
    et al.
    Sork, Victoria L.
    Smouse, Peter E.
    Influence of acorn woodpecker social behaviour on transport of coast live oak (Quercus agrifolia) acorns in a southern California oak savanna2010In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 98, no 3, p. 561-572Article in journal (Refereed)
    Abstract [en]

    1. Many plant species depend upon animals for seed dispersal, yet animals disperse seeds in pursuit of their own social and behavioural agendas. Animal social behaviour affects where and how they forage, so it must also shape patterns of seed dispersal.

    2. At Sedgwick Reserve, California, USA, we established a study population of Quercus agrifolia to determine patterns of acorn foraging by the acorn woodpecker (Melanerpes formicivorous). This cooperative breeder lives in social groups that defend territories surrounding arboreal seed caches (granaries), foraging communally within these territories.

    3. We genotyped pericarp tissue of 568 acorns, as well as 285 adult Q. agrifolia trees, including all adults within 150 m of 16 focal granaries. After quantifying genotyping error, we identified a genetically reliable subset of 524 acorns. We assigned a source tree to each acorn and estimated the number of seed sources per granary and seed source sharing among granaries.

    4. We found one to eight distinct seed-source genotypes per granary, and an effective source diversity ranging from 1.0 to 6.6 seed sources. Of all transport events, 96.5% involve source trees within 150 m of the granaries. For one granary, all sampled acorns were transported from five trees located more than 1.3 km away, with all source trees within 90 m of each other. No measure of seed-source diversity was associated with density of potential seed sources, and the pattern of acorn movement fits three traditional dispersal curves poorly.

    5. Woodpecker groups rarely collected acorns from overlapping sets of maternal sources. Some pairs of neighbouring granaries shared maternal sources, and we identify those that were probably maintained by the same woodpecker group.

    6.Synthesis. Territoriality of woodpecker groups restricts both the spatial area of foraging and the sharing of seed sources. This foraging behaviour limits distances and directions of acorn transport from oaks located within woodpecker territories. Dispersal agents with this type of social structure will create a high degree of local genetic structure. Extreme behavioural variations may result in anomalous long-distance dispersal events that increase genetic connectivity, but are likely to do so in an episodic and erratic fashion.

  • 15.
    Sletvold, Nina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution. Uppsala Univ, EBC, Dept Ecol & Genet, Plant Ecol & Evolut, SE-75236 Uppsala, Sweden..
    Nonlinear costs of reproduction in a long-lived plant2015In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 103, no 5, p. 1205-1213Article in journal (Refereed)
    Abstract [en]

    A trade-off between current reproduction and future performance is a key component of life-history theory, but the shape of this trade-off for any specific fitness component remains elusive. We induced three to five levels of reproductive effort (RE) by manipulating fruit set of a long-lived orchid in two populations that differed in the length of the growing season and local climate and examined survival, size and fecundity the following year. Natural fruit set was 72% higher in the long-season population, but was not associated with a significant survival cost in any population. Survival decreased linearly with experimentally increased RE in the short-season population. In both populations, natural RE incurred growth and fecundity costs, and growth costs increased nonlinearly with diminishing costs at high RE. Fecundity costs increased linearly with RE in the long-season population, but nonlinearly with diminishing costs at high RE in the other. The results demonstrate that the shape of the cost function may be nonlinear with context-dependent intercept, slope and curvature. They are consistent with the prediction that survival costs appear only when RE exceeds natural levels, while growth and fecundity costs are evident at natural RE.Synthesis. We suggest that studies inducing multiple levels of RE are required to understand life-history trade-offs and their context dependence. This kind of information is fundamental for an understanding of the link between environmental heterogeneity, adaptive differentiation and life-history evolution.

  • 16.
    Sundberg, Sebastian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Rydin, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Habitat requirements for establishment of Sphagnum from spores2002In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 90, no 2, p. 268-278Article in journal (Refereed)
    Abstract [en]

    1 The ecological significance of the spore in perennial bryophytes has been questioned. In Sphagnum, protonemata have rarely been observed in the field and P-concentrations in natural waters are insufficient for spore establishment.

    2 We determined requirements for establishment of Sphagnum spores in growth chamber experiments. Up to 17 species were tested on peat with various natural substrates added and with different mire waters. In a field experiment, the effect of cover of nutrient depleted Eriophorum-litter was also tested.

    3 There were large differences between substrates, and establishment appeared to be limited by the amount of phosphate released. Added moose dung or litter of Betula pubescens promoted establishment well above the low level seen on peat alone, or with added litter from Pinus sylvestris.

    4 Species differed slightly in response to different mire waters and to added substrates, but these differences could not be attributed to the natural habitat of the species or their breeding system. There was a weak negative relationship between spore size and establishment success.

    5 In the field experiment, about 1% of the sown, viable spores established in the presence of moose dung or Betula litter. With moose dung there was an indication that protonemata and plants of other bryophytes had a negative effect on the establishment of Sphagnum.

    6 Nutrient release from litter and cover provided by vascular plants are needed to generate safe sites for the establishment of Sphagnum from spores, especially on wet, acidic and relatively nutrient-poor soils and peat. Recruitment from spores may therefore be important in Sphagnum, particularly following disturbance.

  • 17.
    Tye, Matthew R.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution. Univ Cent Florida, Dept Biol, Orlando, FL 32816 USA..
    Menges, Eric S.
    Plant Ecol Program, Archbold Biol Stn, Venus, FL 33960 USA..
    Weekley, Carl
    Plant Ecol Program, Archbold Biol Stn, Venus, FL 33960 USA..
    Quintana-Ascencio, Pedro F.
    Univ Cent Florida, Dept Biol, Orlando, FL 32816 USA..
    Salguero-Gomez, Roberto
    Univ Sheffield, Dept Anim & Plant Sci, Western Bank, Sheffield S10 2TN, S Yorkshire, England.;Univ Queensland, Sch Biol Sci, Ctr Biodivers & Conservat Sci, St Lucia, Qld 4072, Australia.;Max Planck Inst Demog Res, Evolutionary Demog Lab, DE-18057 Rostock, Germany..
    A demographic menage a trois: interactions between disturbances both amplify and dampen population dynamics of an endemic plant2016In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 104, no 6, p. 1778-1788Article in journal (Refereed)
    Abstract [en]

    Natural and anthropogenic disturbances co-occur in most systems, but how they interact to shape demographic outcomes remains poorly understood. Such interactions may alter dynamics of populations in non-additive ways, making demographic predictions challenging when focusing on only one disturbance. Thus, understanding the interactive effects of such disturbances is critically important to determine the population viability of most species under a diversity of stressors. We used a hierarchical integral projection model (IPM), parameterized with 13years of field data across 20 populations, encompassing 2435 individuals of an endangered herb, Liatris ohlingerae. We examined interactive effects of vertebrate herbivory, fire and anthropogenic activities (sand roads) on vital rates (e.g. survival, growth, reproduction, recruitment) and ultimately on population growth rates (), to test the hypothesis that interactions amplify or dampen differences in depending on environmental contexts. We constructed megamatrices to determine coupled dynamics in individuals damaged vs. not damaged by herbivores in roadsides and in Florida scrub with different times since fire. We identified strong interactive effects of fire with herbivory and habitat with herbivory on vital rates and on population growth rates in the IPM model. We also found different patterns of variation in between habitat and time-since-fire scenarios; population growth rates were higher in roadside populations compared to scrub populations and declined with increasing time since fire. Herbivory had interactive effects with both fire and human disturbances on . Herbivory resulted in decreased differences in due to anthropogenic disturbance and slightly increased differences in due to time since fire.Synthesis. The co-occurrence of various disturbances may both amplify and dampen the effects of other disturbances on population growth rate, thus shaping complex population dynamics that are neither linear nor additive. These realistic nonlinearities represent challenges in understanding and projecting of population dynamics. Here, we examined the effects of various sources of disturbance on the population dynamics of an endangered plant species, finding complex interactions affecting population growth rates. We argue that integration of multiple, interacting stressors in IPMs will allow more accurate estimation of the overall effects of ecological processes on species viability.

  • 18.
    Wheeler, Julia A.
    et al.
    WSL Inst Snow & Avalanche Res SLF, CH-7260 Davos, Switzerland.;Univ Basel, Inst Bot, CH-4056 Basel, Switzerland..
    Cortes, Andres J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Sedlacek, Janosch
    Univ Konstanz, Dept Biol, D-78457 Constance, Germany..
    Karrenberg, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    van Kleunen, Mark
    Univ Konstanz, Dept Biol, D-78457 Constance, Germany..
    Wipf, Sonja
    WSL Inst Snow & Avalanche Res SLF, CH-7260 Davos, Switzerland..
    Hoch, Guenter
    Univ Basel, Inst Bot, CH-4056 Basel, Switzerland..
    Bossdorf, Oliver
    Univ Tubingen, Inst Evolut Ecol, D-72076 Tubingen, Germany..
    Rixen, Christian
    WSL Inst Snow & Avalanche Res SLF, CH-7260 Davos, Switzerland..
    The snow and the willows: earlier spring snowmelt reduces performance in the low-lying alpine shrub Salix herbacea2016In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 104, no 4, p. 1041-1050Article in journal (Refereed)
    Abstract [en]

    Current changes in shrub abundance in alpine and arctic tundra ecosystems are primarily driven by climate change. However, while taller shrub communities are expanding, dwarf shrub communities show reductions under climate warming, and the mechanisms driving the latter (such as warming temperatures or accelerated spring snowmelt) may be complex. To determine and disentangle the response of a widespread arctic-alpine prostrate dwarf shrub to both climate warming and changes in snowmelt time, we investigated phenology, clonal and sexual reproduction, leaf size, wood tissue carbon balance and leaf damage in 480 patches of Salix herbacea, along its elevational and snowmelt microhabitat range over 3years in a space-for-time substitution. Earlier snowmelt was associated with longer phenological development periods, an increased likelihood of herbivory and fungal damage, lower stem density, smaller leaves and lower end-of-season wood reserve carbohydrates. Furthermore, while early snowmelt was associated with an increased proportion of flowering stems, the proportion of fruiting stems was not, as fruit set decreased significantly with earlier snowmelt. Warmer temperatures at lower elevations were associated with lower stem numbers and larger leaves.Synthesis. Our study indicates that phenology, fitness proxies and fungal/insect damage of the dwarf shrub S.herbacea are strongly influenced by snowmelt timing, and that earlier spring snowmelt reduced performance in S.herbacea. The likely mechanisms for many of the observed patterns are related to adverse temperature conditions in the early growing season. Reductions in clonal (stem number) and sexual reproduction (reduced fruit set) under earlier snowmelt, in addition to increasing damage probability, will likely lead to lower fitness and poorer performance, particularly in shrubs growing in early-exposure microhabitats. Further, we saw few concurrent benefits of higher temperatures for S.herbacea, particularly as warming was associated with lower clonal growth. As growing seasons become warmer and longer in arctic and alpine tundra ecosystems, early snowmelt is a critical mechanism reducing fitness and performance in a widespread dwarf shrub and may ultimately reduce dwarf shrub communities in tundra biomes.

  • 19.
    Ågren, Jon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ehrlén, Johan
    Solbreck, Christer
    Spatio-temporal variation in fruit production and seed predation in a perennial herb influenced by habitat quality and population size2008In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 96, no 2, p. 334-345Article in journal (Refereed)
    Abstract [en]

    1.  In patchily distributed plant species, seed production is likely to be influenced both by local abiotic factors affecting plant size and conditions for fruit maturation, and by population characteristics affecting the intensity of interactions with mutualists and antagonists. However, the relative importance of these effects is poorly known.

    2. We used multiple regression and path models to examine the importance of abiotic factors (sun exposure, soil depth) and population characteristics (size, density and connectivity) for variation in flower and fruit production and intensity of seed predation among 39 populations of the long-lived herb Vincetoxicum hirundinaria in three consecutive years. In addition, we manipulated water availability in a field experiment and recorded short-term and long-term effects on fruit output, and conducted a supplemental hand-pollination experiment.

    3.  Flower production varied little, while fruit initiation, fruit abortion and fruit predation varied considerably among years. Sun exposure and soil depth affected fruit production per plant indirectly and positively through their effects on flower number. Population density affected fruit production negatively through its effect on flower number. Both fruit initiation and the proportion of fruits attacked by the tephritid fly Euphranta connexa were related positively to population size.

    4.  The number of full-size fruits per plant was related positively to sun exposure and population size in two years each, and related negatively to population density in one year. However, because of seed predation, the number of intact mature fruits was related significantly to population characteristics in only one of three years.

    5.  The field experiments showed that both shortage of water and insufficient pollination may limit fruit set in V. hirundinaria.

    6.  Synthesis. These results demonstrate that the relative importance of local abiotic conditions and population characteristics may vary considerably along the chain of events from flower formation to intact fruit, and also among years. They further show that, at least in species with a naturally patchy distribution, connectivity may be relatively unimportant for variation in reproductive output compared to effects of habitat quality, population size and density.

     

1 - 19 of 19
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf