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  • 1.
    Arnell, Matilda
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Does historical land use affect the regional distribution of fleshy-fruited woody plants?2019In: PLOS ONE, E-ISSN 1932-6203, Vol. 14, no 12, article id e0225791Article in journal (Refereed)
    Abstract [en]

    Species richness and composition of current vegetation may reflect historical land use. We develop and examine the hypothesis that regional distribution and richness of fleshy-fruited woody plants, a group sharing life-form and dispersal system, reflect historical land use in open or semi-open habitats. Historical land use was based on maps from around the year 1900 for two regions in Sweden, and field data was gathered from surveys made in these regions. Species richness was positively related to historical land use indicated as open habitat in 1900. In one of the regions, five out of nine examined species were positively related to historical land use (with historical effect R-2 ranging between 0.03 and 0.22). In the other region, we found a weaker positive relationship with historical land use in two out of nine examined species (R-2 0.01 and 0.02). We conclude that current occurrence and richness of fleshy-fruited woody species is partly a legacy of historical land use, and that regions may vary in this respect. Based on a comparison between the two regions examined here, we discuss some potential causes behind this variation.

  • 2.
    Arnell, Matilda
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Local distribution patterns of fleshy-fruited woody plants - testing the orchard hypothesis2021In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 44, no 3, p. 481-492Article in journal (Refereed)
    Abstract [en]

    Plant distribution patterns are influenced by many different factors. We examined mechanisms behind local distribution patterns of boreo-nemoral fleshy-fruited woody plants with seed dispersal mainly mediated by birds. It has been suggested that guilds of these plants develop 'orchards', i.e. locally aggregated occurrences composed of several species. We analysed spatially explicit occurrence data of different life stages of a local guild of fleshy-fruited woody plants in south-eastern Sweden, and conducted a seedling recruitment experiment for a subset of ten species. Spatial point pattern analyses showed that the guild of fleshy-fruited species was aggregated at small (< 10 m) spatial scales. Saplings were more common under canopies of heterospecific reproductive individuals than expected by chance. These results show that the local guild of fleshy-fruited species is distributed as orchards, i.e. clusters consisting of individuals of different species and life stages. We found no evidence of negative distance dependence between saplings and reproductive conspecific individuals. Results from the recruitment experiment suggest that recruitment is seed limited and generally low among the studied species. At the site-scale (circular areas with 50 m radius), there was no difference in seedling recruitment between sites with and without reproductive conspecific individuals for most species included in the recruitment experiment. This further suggests that the aggregated patterns found are not simply a result of spatial concordance in suitable habitats across life stages. Instead, we suggest that the sheer number of seeds from species in the guild deposited under the crowns of fruit bearing individuals is the main mechanism behind the build-up of orchards. Although further studies are needed to fully disentangle the processes underlying the observed patterns of local diversity, we argue that describing patterns and contrasting them to the predictions of ecologically relevant hypotheses is a useful first step.

  • 3.
    Arnell, Matilda
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Landscape-scale range filling and dispersal limitation of woody plants2022In: Journal of Biogeography, ISSN 0305-0270, E-ISSN 1365-2699, Vol. 49, no 11, p. 2028-2036Article in journal (Refereed)
    Abstract [en]

    Aim: The extent to which species fill their predicted current ranges and the underlying process of dispersal limitation have implications for species' abilities to track climate change. Range filling is intimately related to spatial scale, yet range filling estimates at high resolutions are largely lacking. In this study, we aim to estimate range filling and dispersal limitation at a high resolution for woody plants with different dispersal systems and habitat affinities.

    Location: Sweden.

    Taxon: All genera of woody plants (trees and shrubs).

    Methods: We estimated landscape-scale range filling for 64 species. Two main dispersal systems, vertebrate dispersal and abiotic dispersal, occurred among these species. Range filling was estimated as the realized range divided by the potential range, that is, the occupied proportion of a species' modelled range, at a 1 km2 resolution. We estimated potential ranges using species distribution models and realized ranges from presence records. To increase the likelihood that absences represented true absences the estimations were restricted to areas with high sampling effort. We tested the effects of dispersal system on range filling, controlling for species' habitat affinities.

    Results: Vertebrate-dispersed woody species had significantly lower landscape-scale range filling than species with abiotic dispersal. Range filling was also linked to habitat affinity. Species associated with intermediate levels of light and moisture had the highest range filling estimates.

    Main conclusions: Landscape-scale range filling of woody species is linked to their dispersal traits. When controlling for habitat affinity, our result suggests that dispersal limitation partly explains the lower occupancy in suitable habitat found for vertebrate-dispersed plants. Given that vertebrate-dispersed species fail to reach suitable habitats at this scale, they are less likely to track changes in climate than woody plants with abiotic dispersal.

  • 4.
    Arnell, Matilda
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Reproductive success, fruit removal and local distribution patterns in the early-flowering shrub Daphne mezereum2023In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, no 10, article id e03871Article in journal (Refereed)
    Abstract [en]

    In insect-pollinated, bird-dispersed plants, both investment in reproduction and reproductive success involve interactions between plants and their pollinators and dispersers. The outcome of these plant–animal interactions may be affected by the number of flowers and fruits, as well as by the plants' local environment and by spatial associations among plants. In this study we mapped the spatial distribution of individuals in a population of the early flowering, fleshy-fruited shrub Daphne mezereum, in a forest in boreo-nemoral Sweden. For all mapped individuals we collected data on numbers of flowers and fruits and fruit removal, for three consecutive years. We analysed spatial associations among individuals, and the effects on reproductive performance and fruit removal of plant height, numbers of flowers and fruits, distance to forest edge, and neighbouring flower and fruit density. Our results show that the density of D. mezereum increases with increasing proximity to forest edge. The number of flowers produced, as well as fruit set and fruit removal, show the same positive relationship with increasing proximity to forest edges. We further show that individuals are aggregated up to distances of about 10 m. The flower production of neighbouring conspecific individuals within 10 m is negatively related to fruit set whereas the fruit production of neighbours is positively related to fruit removal. Our main conclusion is that the spatial distribution of D. mezereum affects reproductive success and fruit removal, which in turn has the potential to feed back to the spatial distribution pattern. Combining studies of reproduction with spatial analyses is important to advance our understanding of the dynamics of plant populations. 

  • 5. Baeten, Lander
    et al.
    Warton, David I.
    Van Calster, Hans
    De Frenne, Pieter
    Verstraeten, Gorik
    Bonte, Dries
    Bernhardt-Roemermann, Markus
    Cornelis, Johnny
    Decocq, Guillaume
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Hedl, Radim
    Heinken, Thilo
    Hermy, Martin
    Hommel, Patrick
    Kirby, Keith
    Naaf, Tobias
    Petrik, Petr
    Walther, Gian-Reto
    Wulf, Monica
    Verheyen, Kris
    A model-based approach to studying changes in compositional heterogeneity2014In: Methods in Ecology and Evolution, E-ISSN 2041-210X, Vol. 5, no 2, p. 156-164Article in journal (Refereed)
  • 6.
    Bolmgren, Kjell
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. SLU Swedish University of Agricultural Sciences, Sweden.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Are mismatches the norm? Timing of flowering, fruiting, dispersal and germination and their fitness effects in Frangula alnus (Rhamnaceae)2015In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 124, no 5, p. 639-648Article in journal (Refereed)
    Abstract [en]

    The close morphological and temporal links between phases of plant growth and reproduction call for integrated studies incorporating several reproductive phases from flowering to recruitment, and associated plant-animal interactions. Phenological strategies, as well as plastic phenological response to climate change, incorporate complex interactions between developmental constraints, pollination and seed dispersal. Relationships between reproductive phenology and components of fitness were studied for two years in the north-temperate, self-incompatible, insect-pollinated, and bird-dispersed shrub Frangula alnus (Rhamnaceae). Fruit set, dispersal, germination and juvenile survival, as well as seed mass and juvenile size were measured in relation to flowering, fruiting and germination time. The results suggest that effects of flowering and fruiting time prevailed in subsequent phases, to some extent as far as to the juvenile phase, but effects of timing were complex and had partly opposing effects on different fitness components. Early flowers had higher fruit-set and experiments indicated that synchronous peak flowering increased fruit-set, but later flowers had higher seed mass. Peak fruiting was not associated with peak dispersal. Late fruits derived from late flowers promoted dispersal. Juvenile recruitment was enhanced by increasing seed size. We conclude that the phenology of flowering and fruiting in F. alnus comprises several features, each with different and sometimes counteracting effects on fitness components. From a general perspective, this result implies that we should not expect to find finely tuned matches in timing specifically between flowering and pollinators, and fruiting and seed dispersing birds.

  • 7.
    Bolmgren, Kjell
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Eriksson, Ove
    Seed mass and the evolution of fleshy fruits in angiosperms2010In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 119, no 4, p. 707-718Article, review/survey (Refereed)
    Abstract [en]

    Fleshy fruits, like drupes and berries, have evolved many times through angiosperm history. Two hypotheses suggest that fleshy fruit evolution is related to changes in the seed mass fitness landscape. The reduced dispersal capability following from an increase in seed mass may be counterbalanced by evolution of traits mediating seed dispersal by animals, such as fleshy fruits. Alternatively, increasing availability and capabilities of frugivores promote evolution of fleshy fruits and allow an increase in seed size. Both these hypotheses predict an association between evolution of fleshy fruits and increasing seed size. We investigated patterns of fruit and seed evolution by contrasting seed mass between fleshy and non-fleshy fruited sister clades. We found a consistent association between possession of fleshy fruits and heavier seeds. The direction of fruit type change did not alter this pattern; seed mass was higher in clades where fleshy fruits evolved and lower in clades where non-fleshy fruits evolved, as compared to their sister clades. These patterns are congruent with the predictions from the two hypotheses, but other evidence is needed to distinguish between them. We emphasize the need to integrate studies of seed disperser effectiveness, seed morphology, and plant recruitment success to better understand the frugivores' role in fleshy fruit evolution.

  • 8.
    Bolmgren, Kjell
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Ove, Eriksson
    Stockholm University, Faculty of Science, Department of Botany.
    Fleshy fruits – origins, niche shifts, and diversification.2005In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 109, no 2, p. 255-272Article in journal (Refereed)
    Abstract [en]

    We examined shifts in fruit type, fleshy vs non-fleshy, in relation to habitat-related niche shifts, species richness, and historical distribution, in 50 phylogenetically independent plant lineages. Each lineage consisted of a sister-group pair of fleshy vs non-fleshy taxa and their outgroup. Niche shifts were assessed based on plant community characteristics. Two niche dimensions assumed to reflect community dynamics were derived: spatial predictability of disturbances and canopy closure. Phylogenetically independent origins of fleshy fruit types (1) were correlated with changes to habitats characterized by more shaded and spatially more unpredictable disturbances, (2) had an opposite effect on species richness in woody and herbaceous clades, enhancing species richness in woody clades, and (3) were continuously distributed over a period covering the last 70 million years. These results support the hypothesis that fleshy fruit evolution is driven by vegetation dynamics, and suggest that the strength of frugivore mediated selection on fleshy fruits increases when recruitment sites are spatially unpredictable and/or characterized by low light conditions.

  • 9.
    Cousins, Sara A. O.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    The influence of management history and habitat on plant species richness in a rural hemiboreal landscape, Sweden2002In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 17, no 6, p. 517-529Article in journal (Refereed)
    Abstract [en]

    We explored patterns of plant species richness at different spatial scales in 14 habitats in a Swedish rural landscape. Effects of physical conditions, and relationships between species richness and management history reaching back to the 17 (th) century were examined, using old cadastral maps and aerial photographs. The most species-rich habitats were dry open semi- natural grasslands, midfield islets and road verges. Alpha diversity (species richness within sites) was highest in habitats on dry substrates (excluding bedrock with sparse pines) and beta diversity (species richness among sites) was highest in moist to wet habitats. Alpha and beta components of species richness tended to be inversely related among habitats with similar species richness. Management history influenced diversity patterns. Areas managed as grasslands in the 17 th and 18 th century harboured more species than areas outside the villages. We also found significant relationships between species richness and soil type. Silt proved to be the most species- rich topsoil (10- 20 cm) in addition to thin soils top of on green- or limestone bedrock. The variation in species richness due to local relief or form of the site also showed significant relationships, where flat surfaces had the highest number of species. In contrast, no significant relationship was found between species richness and aspect. Our study suggests that present- day diversity patterns are much influenced by management history, and that small habitat, e. g., road verges and midfield islets, are important for maintaining species richness.

  • 10. Dahlström, Anna
    et al.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    The History (1620-2003) of Land Use, People and Livestock, and the Relationship to Present Plant Species Diversity in a Rural Landscape in Sweden2006In: Environment and History, ISSN 0967-3407, E-ISSN 1752-7023, Vol. 12, p. 191-212Article in journal (Refereed)
    Abstract [en]

    The traditional agriculture in Europe favoured numerous plant and animal species that are presently declining. Integrated studies based on various sources are needed in order to unravel the complex relationships between changing landscapes and biological diversity. The objectives of this study were to describe changes in land use during c. 350 years in a Swedish agricultural landscape in relation to changes in human population and livestock, and to analyse relationships between historical land use and present-day plant species diversity. There were only minor long-term changes in land use, population and livestock between 1640 and 1854 in the two studied hamlets, but detailed data 1620-41 showed a large short-term fluctuation in livestock numbers. After 1854 larger changes took place. Grasslands were cultivated and livestock composition changed. After 1932, livestock number decreased and most of the former grazed outland (areas located outside the fenced infields) turned into forest by natural succession. 7 per cent of the study area is still grazed semi-natural grassland. The highest plant species richness is today found on semi-natural grassland with a long continuity of grazing. The distribution of five target species suggests that previous land use still has an important effect today. The majority of their occurrences are remnant populations located in previous outland pastures which are today forests.

  • 11. De Frenne, Pieter
    et al.
    Graae, Bente J.
    Rodriguez-Sanchez, Francisco
    Kolb, Annette
    Chabrerie, Olivier
    Decocq, Guillaume
    De Kort, Hanne
    De Schrijver, An
    Diekmann, Martin
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gruwez, Robert
    Hermy, Martin
    Lenoir, Jonathan
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Coomes, David A.
    Verheyen, Kris
    Latitudinal gradients as natural laboratories to infer species' responses to temperature2013In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 101, no 3, p. 784-795Article, review/survey (Refereed)
    Abstract [en]

    Macroclimatic variation along latitudinal gradients provides an excellent natural laboratory to investigate the role of temperature and the potential impacts of climate warming on terrestrial organisms. Here, we review the use of latitudinal gradients for ecological climate change research, in comparison with altitudinal gradients and experimental warming, and illustrate their use and caveats with a meta-analysis of latitudinal intraspecific variation in important life-history traits of vascular plants. We first provide an overview of latitudinal patterns in temperature and other abiotic and biotic environmental variables in terrestrial ecosystems. We then assess the latitudinal intraspecific variation present in five key life-history traits [plant height, specific leaf area (SLA), foliar nitrogen:phosphorus (N:P) stoichiometry, seed mass and root:shoot (R:S) ratio] in natural populations or common garden experiments across a total of 98 plant species. Intraspecific leaf N:P ratio and seed mass significantly decreased with latitude in natural populations. Conversely, the plant height decreased and SLA increased significantly with latitude of population origin in common garden experiments. However, less than a third of the investigated latitudinal transect studies also formally disentangled the effects of temperature from other environmental drivers which potentially hampers the translation from latitudinal effects into a temperature signal. Synthesis. Latitudinal gradients provide a methodological set-up to overcome the drawbacks of other observational and experimental warming methods. Our synthesis indicates that many life-history traits of plants vary with latitude but the translation of latitudinal clines into responses to temperature is a crucial step. Therefore, especially adaptive differentiation of populations and confounding environmental factors other than temperature need to be considered. More generally, integrated approaches of observational studies along temperature gradients, experimental methods and common garden experiments increasingly emerge as the way forward to further our understanding of species and community responses to climate warming.

  • 12. De Frenne, Pieter
    et al.
    Rodriguez-Sanchez, Francisco
    Coomes, David Anthony
    Baeten, Lander
    Verstraeten, Gorik
    Vellend, Mark
    Bernhardt-Roemermann, Markus
    Brown, Carissa D.
    Brunet, Jorg
    Cornelis, Johnny
    Decocq, Guillaume M.
    Dierschke, Hartmut
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gilliam, Frank S.
    Hedl, Radim
    Heinken, Thilo
    Hermy, Martin
    Hommel, Patrick
    Jenkins, Michael A.
    Kelly, Daniel L.
    Kirby, Keith J.
    Mitchell, Fraser J. G.
    Naaf, Tobias
    Newman, Miles
    Peterken, George
    Petrik, Petr
    Schultz, Jan
    Sonnier, Gregory
    Van Calster, Hans
    Waller, Donald M.
    Walther, Gian-Reto
    White, Peter S.
    Woods, Kerry D.
    Wulf, Monika
    Graae, Bente Jessen
    Verheyen, Kris
    Microclimate moderates plant responses to macroclimate warming2013In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 110, no 46, p. 18561-18565Article in journal (Refereed)
    Abstract [en]

    Recent global warming is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., thermophilization of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that climatic lags may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate warming, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of 12-67 y, we document significant thermophilization of ground-layer plant communities. These changes reflect concurrent declines in species adapted to cooler conditions and increases in species adapted to warmer conditions. However, thermophilization, particularly the increase of warm-adapted species, is attenuated in forests whose canopies have become denser, probably reflecting cooler growing-season ground temperatures via increased shading. As standing stocks of trees have increased in many temperate forests in recent decades, local microclimatic effects may commonly be moderating the impacts of macroclimate warming on forest understories. Conversely, increases in harvesting woody biomass-e.g., for bioenergy-may open forest canopies and accelerate thermophilization of temperate forest biodiversity.

  • 13. De Schuyter, Wim
    et al.
    De Lombaerde, Emiel
    Depauw, Leen
    De Smedt, Pallieter
    Stachurska-Swakon, Alina
    Orczewska, Anna
    Teleki, Balázs
    Jaroszewicz, Bogdan
    Closset, Déborah
    Máliš, František
    Mitchell, Fraser
    Schei, Fride Høistad
    Peterken, George
    Decocq, Guillaume
    Van Calster, Hans
    Šebesta, Jan
    Lenoir, Jonathan
    Brunet, Jörg
    Reczyńska, Kamila
    Świerkosz, Krzysztof
    Diekmann, Martin
    Kopecký, Martin
    Chudomelová, Markéta
    Hermy, Martin
    Macek, Martin
    Newman, Miles
    Wulf, Monika
    Vild, Ondřej
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Horchler, Peter
    Petrik, Petr
    Pielech, Remigiusz
    Heinken, Thilo
    Dirnböck, Thomas
    Nagel, Thomas A.
    Durak, Tomasz
    Standovár, Tibor
    Naaf, Tobias
    Schmidt, Wolfgang
    Baeten, Lander
    De Frenne, Pieter
    Bernhardt-Römermann, Markus
    Hédl, Radim
    Waller, Don
    Verheyen, Kris
    Declining potential nectar production of the herb layer in temperate forests under global change2024In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 112, no 4, p. 832-847Article in journal (Refereed)
    Abstract [en]
    1. Wild pollinators are crucial for ecosystem functioning and human food production and often rely on floral resources provided by different (semi-) natural ecosystems for survival. Yet, the role of European forests, and especially the European forest herb layer, as a potential provider of floral resources for pollinators has scarcely been quantified.
    2. In this study, we measured the potential nectar production (PNP) of the forest herb layer using resurvey data across 3326 plots in temperate forests in Europe, with an average time interval of 41 years between both surveys in order to assess (i) the importance of the forest herb layer in providing nectar for wild pollinators, (ii) the intra-annual variation of PNP, (iii) the overall change in PNP between survey periods and (iv) the change in intra-annual variation of PNP between survey periods. The PNP estimates nectar availability based on the relative cover of different plant species in the forest herb layer. Although PNP overestimates actual nectar production, relative differences amongst plots provide a valid and informative way to analyse differences across time and space.
    3. Our results show that the forest herb layer has a large potential for providing nectar for wild pollinator communities, which is greatest in spring, with an average PNP of almost 16 g sugar/m2/year. However, this potential has drastically declined (mean plot-level decline >24%).
    4. Change in light availability, associated with shifts in canopy structure and canopy composition, is the key driver of temporal PNP changes.
    5. Synthesis. Our study shows that if management activities are carefully planned to sustain nectar-producing plant species for wild pollinators, European forest herb layers and European forests as a whole can play key roles in sustaining wild pollinator populations.
  • 14.
    Elmhagen, Bodil
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Implications of climate and land-use change for landscape processes, biodiversity, ecosystem services, and governance2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, p. s1-S5Article in journal (Refereed)
    Abstract [en]

    This introduction to the Special Issue summarizes the results of 14 scientific articles from the interdisciplinary research program Ekoklim at Stockholm University, Sweden. In this program, we investigate effects of changing climate and land use on landscape processes, biodiversity, and ecosystem services, and analyze issues related to adaptive governance in the face of climate and land-use change. We not only have a research focus on the 22 650 km(2) Norrstrom catchment surrounding lake Malaren in south-central Sweden, but we also conduct research in other Swedish regions. The articles presented here show complex interactions between multiple drivers of change, as well as feedback processes at different spatiotemporal scales. Thus, the Ekoklim program highlights and deals with issues relevant for the future challenges society will face when land-use change interacts with climate change.

  • 15.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    A closer look at the species behind abundance-occupancy relationships2013In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 24, no 4, p. 589-590Article in journal (Other academic)
    Abstract [en]

    Guedo & Lamb (), in this issue of the Journal of Vegetation Science, used a 35-yr data series from two prairie communities to show that abundance-occupancy relationships change over time. Scrutinizing the details behind this finding, they show that species groups follow different trajectories during succession after disturbance. These results will inspire further species-level studies unraveling mechanisms behind abundance-occupancy relationships.

  • 16.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Coproduction of Food, Cultural Heritage and Biodiversity by Livestock Grazing in Swedish Semi-natural Grasslands2022In: Frontiers in Sustainable Food Systems, E-ISSN 2571-581X, Vol. 6, article id 801327Article in journal (Refereed)
    Abstract [en]

    Livestock has been a backbone of people's livelihood as long as agriculture has existed in Scandinavia, c. 6,000 years. In the early Iron Age, c. 2,000 years ago, a land management system began to form, composed of infields (enclosed hay-meadows and crop fields) and outlying land used for livestock grazing. Despite many later innovations and societal changes affecting agricultural technology and practices, this way of organizing land use was a template for how landscapes were managed and structured until the modernization of agriculture and forestry during the last centuries. There are legacies of this historic land-use, mainly as semi-natural grasslands managed by livestock grazing (open or semi-open; long continuity of management; not much influenced by commercial fertilizers, plowing etc.). These semi-natural grasslands harbor an exceptional small-scale biodiversity, particularly plants and insects. Landscapes with semi-natural grasslands represent cultural heritage, and are appreciated for their beauty. The total area of semi-natural grasslands has declined considerably during the past 100 years, and the current trend suggest that further declines are expected. A large fraction of threatened biodiversity in Sweden thrives in these grasslands. Livestock grazing in semi-natural grasslands makes an important contribution to food production, and there is an increasing interest in consumption of products, mainly meat, from these grasslands. This implies that there is a positive feedback between food production, maintenance of biological diversity, and cultural heritage. This paper gives an overview of semi-natural grasslands, focusing on Sweden, from a historic, cultural and ecological perspective, and aims at discussing challenges and prospects for developing and maintaining positive associations between producing food, biodiversity, and cultural heritage, in the future.

  • 17.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Domesticated Forest Landscapes in Central Scandinavia during the Iron Age: Resource Colonization for Iron and Subsistence Strategies based on Livestock2023In: Journal of field archaeology, ISSN 0093-4690, E-ISSN 2042-4582, Vol. 48, no 4, p. 315-326Article in journal (Refereed)
    Abstract [en]

    This study explores how resource colonization for iron in central Sweden during the early Iron Age may have affected the use of forest landscapes. Slag heap volume at iron production sites was used to estimate the amount of forest resources required for charcoal production. Forest resources required for livestock grazing and fodder were estimated from literature sources. To produce charcoal at iron production sites, forests were harvested, creating conditions suitable for grazing. Production of livestock winter fodder, leaf-hay, became a constraint due to the conflict between grazing grounds and fodder producing areas near main settlements. Although availability of forest was not limiting, a combination of opportunities and constraints is suggested to have promoted a new spatial ordering of land use. This included land closest to the main settlements allocated to fodder production and development of secondary seasonal settlements (shielings) at iron production sites, which could be exploited for livestock grazing. 

  • 18.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Evolution of angiosperm seed disperser mutualisms: the timing of origins and their consequences for coevolutionary interactions between angiosperms and frugivores2016In: Biological Reviews, ISSN 1464-7931, E-ISSN 1469-185X, Vol. 91, no 1, p. 168-186Article in journal (Refereed)
    Abstract [en]

    The origins of interactions between angiosperms and fruit-eating seed dispersers have attracted much attention following a seminal paper on this topic by Tiffney (1984). This review synthesizes evidence pertaining to key events during the evolution of angiosperm-frugivore interactions and suggests some implications of this evidence for interpretations of angiosperm-frugivore coevolution. The most important conclusions are: (i) the diversification of angiosperm seed size and fleshy fruits commenced around 80million years ago (Mya). The diversity of seed sizes, fruit sizes and fruit types peaked in the Eocene around 55 to 50Mya. During this first phase of the interaction, angiosperms and animals evolving frugivory expanded into niche space not previously utilized by these groups, as frugivores and previously not existing fruit traits appeared. From the Eocene until the present, angiosperm-frugivore interactions have occurred within a broad frame of existing niche space, as defined by fruit traits and frugivory, motivating a separation of the angiosperm-frugivore interactions into two phases, before and after the peak in the early Eocene. (ii) The extinct multituberculates were probably the most important frugivores during the early radiation phase of angiosperm seeds and fleshy fruits. Primates and rodents are likely to have been important in the latter part of this first phase. (iii) Flying frugivores, birds and bats, evolved during the second phase, mainly during the Oligocene and Miocene, thus exploiting an existing diversity of fleshy fruits. (iv) A drastic climate shift around the Eocene-Oligocene boundary (around 34Mya) resulted in more semi-open woodland vegetation, creating patchily occurring food resources for frugivores. This promoted evolution of a flying frugivore niche' exploited by birds and bats. In particular, passerines became a dominant frugivore group worldwide. (v) Fleshy fruits evolved at numerous occasions in many angiosperm families, and many of the originations of fleshy fruits occurred well after the peak in the early Eocene. (vi) During periods associated with environmental change altering coevolutionary networks and opening of niche space, reciprocal coevolution may result in strong directional selection formative for both fruit and frugivore evolution. Further evidence is needed to test this hypothesis. Based on the abundance of plant lineages with various forms of fleshy fruits, and the diversity of frugivores, it is suggested that periods of rapid coevolution in angiosperms and frugivores occurred numerous times during the 80million years of angiosperm-frugivore evolution.

  • 19.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Evolution of seed size and biotic seed dispersal in angiosperms: paleoecological and neoecological evidence2008In: International Journal of Plant Sciences, Vol. 169, p. 863-870Article in journal (Refereed)
  • 20.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Evolution of the seed habit: Is niche construction a missing component?2018In: Ideas in ecology and evolution, ISSN 1918-3178, Vol. 11, no 1, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Evolution of land plants is one of the major transitions in the history of life on Earth. In this process, evolution of seeds constitutes one of the key events, liberating plants from dependence of free external water for fertilization, thus promoting colonization of dry environments and the build-up of terrestrial ecosystems. Previous explanations of evolution of seeds from heterosporous predecessors have been based on a framework of kin and sexual selection theory. Here I suggest that that niche construction is a missing component in these explanations. During colonization of increasingly drier habitats, the heterosporous life cycle was subjected to strong spatial and temporal gradients in water availability. The ancestral condition of separate niches of the sporophyte and female gametophyte generations changed into a situation where the sporophyte generation provided the means by which female gametophytes could develop, in effect 'constructing' the recruitment niche for the female gametophyte, attached to the sporophyte. Selection favored modifications in the developmental program, altering the relative timing of fertilization and dispersal. Kin and sexual selection processes could then play out in the context of a plant life cycle where fertilization preceded dispersal, eventually forming the seed habit. Niche construction by the sporophyte removed the ecological independence of the two generations; the sporophyte provided the female gametophyte with a recruitment niche, transforming the biphasic life cycle into a unitary life cycle, and promoted an expansion of the ecological niche zone for land plants, eventually leading to a vegetation covering most parts of the land mass.

  • 21.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Floristic Legacies of Historical Land Use in Swedish Boreo-Nemoral Forests: A Review of Evidence and a Case Study on Chimaphila umbellata and Moneses uniflora2022In: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 13, no 10, article id 1715Article, review/survey (Refereed)
    Abstract [en]

    Many forests throughout the world contain legacies of former human impacts and management. This study reviews evidence of floristic legacies in the understory of Swedish boreo-nemoral forests, and presents a case study on two currently declining forest plants, suggested to have been favored by historical use of forests. The review provides evidence of forest remnant populations of 34 grassland species. Thus, many floristic legacies have their main occurrence in semi-natural grasslands, but maintain remnant populations in forests, in some cases more than 100 years after grazing and mowing management have ceased. Despite less information on true forest understory plants appearing as legacies of historical human use of boreo-nemoral forests, a putative guild of such species is suggested. The case study on two species, Chimaphila umbellata and Moneses uniflora (Pyroleae, Ericaceae) suggests that both species are currently declining, mainly due to modern forestry and ceased livestock grazing in forests. Chimaphila maintains remnant populations during decades, due to its extensive clonal capacity and its long-lived ramets. Moneses is more sensitive, due to a lower stature, weaker clonal capacity and short-lived ramets, flowering only once during their lifetime. Thus, Moneses have more transient occurrences, and will decline rapidly under deteriorating conditions.

  • 22.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Historical and Current Niche Construction in an Anthropogenic Biome: Old Cultural Landscapes in Southern Scandinavia2016In: Land, E-ISSN 2073-445X, Vol. 5, no 4, article id 42Article in journal (Refereed)
    Abstract [en]

    Conceptual advances in niche construction theory provide new perspectives and a tool-box for studies of human-environment interactions mediating what is termed anthropogenic biomes. This theory is useful also for studies on how anthropogenic biomes are perceived and valued. This paper addresses these topics using an example: old cultural landscapes in Scandinavia, i.e., landscapes formed by a long, dynamic and continuously changing history of management. Today, remnant habitats of this management history, such as wooded pastures and meadows, are the focus of conservation programs, due to their rich biodiversity and cultural and aesthetic values. After a review of historical niche construction processes, the paper examines current niche construction affecting these old cultural landscapes. Features produced by historical niche construction, e.g., landscape composition and species richness, are in the modern society reinterpreted to become values associated with beauty and heritage and species' intrinsic values. These non-utilitarian motivators now become drivers of new niche construction dynamics, manifested as conservation programs. The paper also examines the possibility to maintain and create new habitats, potentially associated with values emanating from historical landscapes, but in transformed and urbanized landscapes.

  • 23.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Naturbetesmarkernas växter: Ekologi, artrikedom och bevarandebiologi2007Report (Other (popular science, discussion, etc.))
  • 24.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Niche shifts and seed limitation as mechanisms determining seedling recruitment in clonal plants2011In: Preslia, ISSN 0032-7786, E-ISSN 2570-950X, Vol. 83, no 3, p. 301-314Article in journal (Refereed)
    Abstract [en]

    This is a review of the evidence on seedling recruitment patterns in clonal forest plants, based on a previously used typology in which the occurrence of seedling recruitment is related to the performance of adult genets: repeated seedling recruitment (RSR), initial seedling recruitment (ISR), recruitment at windows of opportunity (RWO) and systematic spatial variation in seedling dynamics among local populations (RSR/ISR). Generally, seedling recruitment in clonal populations is common and the majority of species have the capacity to recruit within established adult populations. All four recruitment patterns are documented in studies, which include both genetic and demographic evidence that support the existence of a range of variation in seedling recruitment among clonal plants. However, it is suggested that this four-category typology should be replaced by a framework based on two continuously varying factors: the degree of niche overlap between juvenile and adult life cycle stages (uncoupling of juvenile and adult niches implies niche shifts) and of seed limitation during recruitment. This creates a hypothetical continuous space within which all recruitment patterns are placed and stimulates research to focus on identifying mechanisms determining the variation in the recruitment of clonal plants. Some further implications of this framework are briefly discussed.

  • 25.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Origin and development of managed meadows in Sweden: a review2020In: Rural Landscapes: Society, Environment, History, E-ISSN 2002-0104, Vol. 7, no 1, p. 1-23Article in journal (Refereed)
    Abstract [en]

    This review concerns when and why infield meadows developed, i.e. enclosed land, constructed and managed for production of livestock fodder. Meadows have been associated with ‘stalling’ of livestock, in turn associated with, for example, protection from adverse weather conditions, increasing efficiency of milk and manure production, or changing human-animal relationships. The suggested timing for origin of meadows ranges from the Neolithic to the Iron Age. Meadows are embedded in a complex of interactions, including aspects of culture, material conditions and the environment, and these were treated as different components, unfolding over time: harvesting fodder, stalling livestock, milk production, use of manure, crops and permanent fields, fencing systems, tools, and settlements and land ownership. The interpretation is based on Hodder’s entanglement theory. It is concluded that these component’s appearance is distributed over a very long time, from the Neolithic to the first centuries AD, when meadows, viewed as a ‘complete’ system, appeared. People most likely for long knew the advantages of feeding livestock, and the means to achieve this: collecting additional fodder, keep livestock in close quarters, eventually indoors, and collect and distribute manure on crop fields, but the introduction of iron tools during the centuries around AD was the key to develop meadows. Stalling livestock and construction of infield meadows may have been partly decoupled. Although climate change was not a driver behind development of meadows, the agricultural system with meadows and livestock stalling was adaptive during later periods of climate deterioration, and for colonization of northern forests in Sweden.

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  • 26.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Species pools in cultural landscapes - niche construction, ecological opportunity and niche shifts2013In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 36, no 4, p. 403-413Article, review/survey (Refereed)
    Abstract [en]

    This paper discusses the ecology of species that were favoured by the development of the cultural landscape in central and NW Europe beginning in the Neolithic and the Bronze Age, with a focus on mechanisms behind species responses to this landscape transformation. A fraction of species may have maintained their realized niches from the pre- agricultural landscape and utilized similar niches created by the landscape transformation. However, I suggest that many species responded by altering their niche relationships, and a conceptual model is proposed for this response, based on niche construction, ecological opportunity and niche shifts. Human-mediated niche construction, associated with clearing of forests and creation of pastures and fields promoted niche shifts towards open habitats, and species exploited the ecological opportunity provided by these created environments. This process was initially purely ecological, i.e. the new habitats must have been included in the original fundamental niche of the species. Two other features of human-mediated niche construction, increased interconnectivity and increased spatial stability of open habitats, resulted in species accumulating in the habitats of the constructed landscape. As a consequence, selection processes were initiated favouring traits promoting fitness in the constructed landscape. This process implied a feed-back to niche shifts, but now also including evolutionary changes in fundamental niches. I briefly discuss whether this model can be applied also to present-day anthropogenic impact on landscapes. A general conclusion is that ecological and evolutionary changes in species niches should be more explicitly considered in modeling and predictions of species response to present-day landscape and land-use changes.

  • 27.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    The importance of traditional agricultural landscapes for preventing species extinctions2021In: Biodiversity and Conservation, ISSN 0960-3115, E-ISSN 1572-9710, Vol. 30, no 5, p. 1341-1357Article in journal (Refereed)
    Abstract [en]

    The main paradigm for protection of biodiversity, focusing on maintaining or restoring conditions where humans leave no or little impact, risks overlooking anthropogenic landscapes harboring a rich native biodiversity. An example is northern European agricultural landscapes with traditionally managed semi-natural grasslands harboring an exceptional local richness of many taxa, such as plants, fungi and insects. During the last century these grasslands have declined by more than 95%, i.e. in the same magnitude as other, internationally more recognized declines of natural habitats. In this study, data from the Swedish Red List was used to calculate tentative extinction rates for vascular plants, insects (Lepidoptera, Coleoptera, Hymenoptera) and fungi, given a scenario where such landscapes would vanish. Conservative estimates suggest that abandonment of traditional management in these landscapes would result in elevated extinction rates in all these taxa, between two and three orders of magnitude higher than global background extinction rates. It is suggested that the species richness in these landscapes reflects a species pool from Pleistocene herbivore-structured environments, which, after the extinction of the Pleistocene megafauna, was rescued by the introduction of pre-historic agriculture. Maintaining traditionally managed agricultural landscapes is of paramount importance to prevent species loss. There is no inherent conflict between preservation of anthropogenic landscapes and remaining 'wild' areas, but valuating also anthropogenic landscapes is essential for biodiversity conservation.

  • 28.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Vegetation change and eco-evolutionary dynamics2014In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 25, no 5, p. 1141-1147Article in journal (Refereed)
    Abstract [en]

    Question: Eco-evolutionary dynamics is a concept encapsulating a feedback between ecology and evolution, acting on short ecological time-scales. Recent studies suggest that such dynamics have been generally over-looked. The objective of this paper is to examine how eco-evolutionary dynamics may contribute to vegetation science. Location: Global. Methods: In this paper I discuss eco-evolutionary dynamics in the context of vegetation science, with a focus on effects derived from human-mediated niche construction, manifested as new habitats, non-native species, and changing connectivity and spatial configuration of habitats. Results and Conclusions: I suggest that eco-evolutionary dynamics have the potential to influence plant community composition and assembly, and thus that eco-evolutionary dynamics should become focus of studies in vegetation science.

  • 29.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    What is biological cultural heritage and why should we care about it? An example from Swedish rural landscapes and forests2018In: Nature Conservation, ISSN 1314-6947, E-ISSN 1314-3301, no 28, p. 1-32Article, review/survey (Refereed)
    Abstract [en]

    There is currently a growing concern that biocultural heritage is threatened in many landscapes. This paper focuses on biological cultural heritage, broadly meaning biological cultural traces that are considered as heritage, but leaving out other aspects of the biocultural heritage concept. An operational definition of biological cultural heritage (BCH) is suggested, based on niche construction theory: biological manifestations of culture, reflecting indirect or intentional effects, or domesticated landscapes, resulting from historical human niche construction. Some factors that influence recognition of BCH are discussed, using a comparison between Swedish open to semi-open vs. forested landscapes. While the former landscapes are generally associated with biological cultural values, BCH is generally over-looked in forests. Two main reasons for this are suggested: loss of cultural memory and a perception of forests as wilderness. A conclusion is that recognition of BCH is essential for guiding development of biological conservation programmes in forests, irrespective of whether the conservation goal is to focus on culturally impacted forests or to conserve what is considered as close to pristine forests. Furthermore, recognising BCH in forests will promote interest and learning of the history of forests and their values and will be informative for developing conservation programmes for all biota in forests, not only those that historically were favoured by culture. Hence, there is no inherent conflict between preserving relatively untouched forests and those with remaining traces of pre-industrial forest management. The recognition of BCH in forests will inspire and promote further integration of cultural and natural heritage research.

  • 30.
    Eriksson, Ove
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Arnell, Matilda
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Niche construction, entanglement and landscape domestication in Scandinavian infield systems2017In: Landscape research, ISSN 0142-6397, E-ISSN 1469-9710, Vol. 42, no 1, p. 78-88Article in journal (Refereed)
    Abstract [en]

    Domesticated landscapes are formed by complex social and ecological interactions. We study present-day remnants of species-rich hay meadows and pastures in Scandinavia, with historical roots in former infield systems', initially developed during the first centuries AD and maintained until the modernisation of agriculture during the nineteenth and twentieth centuries. Infield systems include infields, enclosed areas near farms incorporating hay meadows and crop fields, and surrounding outlying land used mainly for grazing. We interpret the development of Scandinavian infield systems and their relationship to vegetation and human culture using concepts of niche construction and entanglement. A key issue revolves around spatio-temporal stabilisation of managed grasslands, in turn related to a complex of interactions between cultural development (e.g. perceptions of land ownership and management practices) and ecological patterns (e.g. species richness). We propose that niche construction and entanglement are useful concepts bridging studies in social history and ecology, and for developing conservation programmes in cultural landscapes.

  • 31.
    Eriksson, Ove
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Arnell, Matilda
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Lindholm, Karl-Johan
    Historical Ecology of Scandinavian Infield Systems2021In: Sustainability, E-ISSN 2071-1050, Vol. 13, no 2, article id 817Article in journal (Refereed)
    Abstract [en]

    Infield systems originated during the early Iron Age and existed until the 19th century, although passing many transitions and changes. The core features of infield systems were enclosed infields with hay-meadows and crop fields, and unenclosed outland mainly used for livestock grazing. We examine the transitions and changes of domesticated landscapes with infield systems using the framework of human niche construction, focusing on reciprocal causation affecting change in both culture and environment. A first major transition occurred during the early Middle Ages, as a combined effect of a growing elite society and an increased availability of iron promoted expansion of villages with partly communal infields. A second major transition occurred during the 18th and 19th centuries, due to a then recognized inefficiency of agricultural production, leading to land reforms. In outlands, there was a continuous expansion of management throughout the whole period. Even though external factors had significant impacts as well, human niche construction affected a range of cultural and environmental features regarding the management and structure of domesticated landscapes with infield systems. Thus, niche construction theory is a useful framework for understanding the historical ecology of infield systems.

  • 32.
    Eriksson, Ove
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bolmgren, Kjell
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Swedish University of Agricultural Sciences, Sweden.
    Westin, Anna
    Lennartsson, Tommy
    Historic hay cutting dates from Sweden 1873-1951 and their implications for conservation management of species-rich meadows2015In: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 184, p. 100-107Article in journal (Refereed)
    Abstract [en]

    Semi-natural hay meadows are species rich habitats, formed by a long history of management and they have experienced a drastic decline all over Europe. There is a vast literature on conservation and species diversity of semi-natural hay-meadows, but very limited information on historic timing of hay cutting. We analyzed data collected between 1873 and 1951 on hay cutting dates and phenology of six plant species from farms distributed across Sweden. The data set comprised 16,015 observations from 175 sites. Results show that date of start and end of hay cutting varied across Sweden. The start of hay cutting was generally delayed by 2.2 days per latitudinal degree and 1.5 days per 100 m altitude, while the end of hay cutting was generally delayed by 2.9 days per latitudinal degree and 2.5 days per 100 m altitude. The average hay cutting period was 18.5 +/- 6.6 days, and became slightly shorter northwards. Site-specific factors had a great impact on when hay cutting was performed, as indicated by a significant correlation between flowering (and leafing) phenology in other species and start date of hay cutting. Today, management for conservation is usually related to a calendar date (e.g. regulated in eligibility criteria and requirements for payment in agri-environment programs in EU). In order to mimic historic management that formed this habitat, management should instead account for latitude and altitude, between-year variation in timing of hay cutting, variation in both start and end dates of hay cutting and if possible local phenological conditions.

  • 33.
    Eriksson, Ove
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Bruun, Hans Henrik
    Stockholm University, Faculty of Science, Department of Botany.
    Land-use history and fragmentation of traditionally managed grasslands in Scandinavia2002In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 13, no 5, p. 743-748Article in journal (Refereed)
    Abstract [en]

    Plants associated with traditional agricultural landscapes in northern Europe and Scandinavia are subjected to drastic habitat fragmentation. In this paper we discuss species response to fragmentation, against a background of vegetation and land-use history. Recent evidence suggests that grassland-forest mosaics have been prevalent long before the onset of human agriculture. We suggest that the creation of infield meadows and outland grazing (during the Iron Age) increased the amount and spatial predictability of grasslands, resulting in plant communities with exceptionally high species densities. Thus, distribution of plant species in the present-day landscape reflects historical land-use. This holds also when traditional management has ceased, due to a slow response by many species to abandonment and fragmentation. The distribution patterns are thus not in equilibrium with the present habitat distribution. Fragmentation influences remaining semi-natural grasslands such that species density is likely to decline as a result of local extinctions and invasion by habitat generalists. However, species that for a long time have been subjected to changing mosaic landscapes may be more resistant to fragmentation than is usually believed. Conservation should focus not only on 'hot-spots' with high species richness, but also consider species dynamics in a landscape context.

  • 34.
    Eriksson, Ove
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Seedling recruitment and population ecology2008In: Seedling Ecology and Evolution, Cambridge University Press, Cambridge , 2008, p. 239-254Chapter in book (Refereed)
  • 35.
    Eriksson, Ove
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Glav Lundin, Linnea
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    'Gooseberry is the only thing left' - a study of declining biological cultural heritage at abandoned crofts in the province of Sodermanland, Sweden2020In: International Journal of Heritage Studies (IJHS), ISSN 1352-7258, E-ISSN 1470-3610, Vol. 26, no 11, p. 1061-1076Article in journal (Refereed)
    Abstract [en]

    This is a study about cultivated and 'wild' plants as components of the material heritage of crofters, an overlooked group of people in former agrarian landscapes. Despite abundant remains of crofts in Sweden, inhabited during the period from the eighteenth century until the 1940s, crofters have been subject to few studies. We used a survey conducted 1967 of botanical remains at abandoned croft as a basis for a re-survey in 2019. As with all biological traces of former human activities, cultivated plants and wild species favoured by former management ultimately disappear, but with long delays. We describe the patterns of this decline. In general, about a third of the species were gone after 52 years. The rate of disappearance of single species occurrences was about 1% annually. We discuss the interpretation of botanical remains from since long abandoned crofts in the context of heritage. In some cases, the botanical remains were the only material evidence left. We conclude that the material heritage of crofters deserves further studies and that botanical remains at abandoned crofts should be documented and at least at some sites protected.

  • 36.
    Eriksson, Ove
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Glav Lundin, Linnea
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Legacies of historic charcoal production affect the forest flora in a Swedish mining district2021In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 39, no 11, article id e03312Article in journal (Refereed)
    Abstract [en]

    Iron production was historically associated with major impacts on forests worldwide, as vast amounts of wood were harvested to produce the charcoal needed for heating the furnaces and reducing iron oxides in the ore to iron. This impact has left abundant legacies which potentially may remain in the present-day vegetation. We investigated how remains of historic charcoal production, mainly from the 18th to the early 20th century, at still remaining charcoal kiln platforms (CKPs), affect the current species richness, species occurrences and cover of vascular plants in the ground vegetation in a Swedish mining district located in the boreo-nemoral forest zone. CKPs have a significantly higher species richness than the surrounding forest, and they also affect cover (negatively) for ericaceous species typically dominating the forest ground vegetation. Several forest species are more frequent at CKPs, and these also harbor significantly more uncommon species, of which many are typical for traditionally managed grasslands. These latter species are likely to represent remnants in present-day forests reflecting former land-use such as livestock grazing. The soil chemistry at CKPs is strongly deviating from the surrounding forest, and this, together with a lower cover of ericaceous shrubs, are the most likely mechanisms behind the higher species richness. CKPs represent conspicuous and abundant historic anthropogenic habitats in the forest vegetation. As far as we are aware, the flora at CKPs in boreal and boreo-nemoral forests has not previously been investigated in detail, and they deserve more attention, both from a biological and a cultural–historical perspective. 

  • 37.
    Eriksson, Ove
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Kainulainen, Kent
    Stockholm University, Faculty of Science, Department of Botany.
    The evolutionary ecology of dust seeds2011In: Perspectives in plant ecology, evolution and systematics, ISSN 1433-8319, E-ISSN 1618-0437, Vol. 13, no 2, p. 73-87Article, review/survey (Refereed)
    Abstract [en]

    Dust seeds are the smallest existing seeds in angiosperms. This paper summarizes taxonomic distribution, phylogeny, ontogeny, morphology, and recruitment behavior of dust seeds, concluding with a general hypothesis on the evolution of dust seeds. Plants with dust seeds depend on external sources of organic carbon for seedling development and are thus parasitic during recruitment. Species with dust seeds are either mycoheterotrophic (fully or partially) or parasitic on plants. Dust seeds are a derived feature which has evolved independently in at least 12 families (Burmanniaceae, Corsiaceae, Orchidaceae, Triuridaceae, Petrosaviaceae, Ericaceae, Gentianaceae, Polygalaceae, Orobanchaceae, Rubiaceae, Buddlejaceae and Gesneriaceae). For the three latter families parasitic behavior during recruitment has not yet been described, and should be considered as a hypothesis. Many, but not all, dust seeds possess features that are likely to have been selected for increasing buoyancy in air or water. Selection for maximal fecundity at the expense of reducing maternal resources per seed is the probable driver of dust seed evolution. As endosperm was reduced, undifferentiated embryo evolved as a by-product due to endosperm mediated control of embryo development. Ultimately, seed size reduction passed a threshold where resource acquisition became dependent on external hosts. In order to embark on an evolutionary trajectory towards host dependence, facultative parasitism must have been established in ancestral lineages. Mycoheterotrophic and mixotrophic plants probably evolved along with the rise of angiosperm dominated tropical forests beginning in the Late Cretaceous. It is suggested that selection for increasing seed size associated with the expansion of modern type tropical forests spurred a competition/colonization trade-off initiating a reversed evolutionary trajectory towards smaller seeds. A different process is suggested for true parasites with dust seeds (Orobanchaceae), where the driver may have been the Mid-Tertiary expansion of grasslands, creating opportunities to exploit grasses and herbs. It is suggested that inequality and asymmetry in resource monopolization in ecosystems promote evolution of subordinate life strategies, and possession of dust seeds is considered as a subordinate strategy in plant communities dominated by other plant strategies. This escape route for ecological losers eventually promoted evolution of one of the most diverse groups of plants, the orchids.

  • 38.
    Eriksson, Ove
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Persson, Lennart
    Umeå university.
    A spatial dimension of ecology: Ilkka Hanski Crafoord Laureate2011In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, ISSN 0044-7447, Vol. 40, no 3, p. 247-247Article in journal (Refereed)
  • 39. Flores, Olivier
    et al.
    Garnier, Eric
    Wright, Ian J.
    Reich, Peter B.
    Pierce, Simon
    Diaz, Sandra
    Pakeman, Robin J.
    Rusch, Graciela M.
    Bernard-Verdier, Maud
    Testi, Baptiste
    Bakker, Jan P.
    Bekker, Renee M.
    Cerabolini, Bruno E. L.
    Ceriani, Roberta M.
    Cornu, Guillaume
    Cruz, Pablo
    Delcamp, Matthieu
    Dolezal, Jiri
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Fayolle, Adeline
    Freitas, Helena
    Golodets, Carly
    Gourlet-Fleury, Sylvie
    Hodgson, John G.
    Brusa, Guido
    Kleyer, Michael
    Kunzmann, Dieter
    Lavorel, Sandra
    Papanastasis, Vasilios P.
    Perez-Harguindeguy, Natalia
    Vendramini, Fernanda
    Weiher, Evan
    An evolutionary perspective on leaf economics: phylogenetics of leaf mass per area in vascular plants2014In: Ecology and Evolution, E-ISSN 2045-7758, Vol. 4, no 14, p. 2799-2811Article in journal (Refereed)
    Abstract [en]

    In plant leaves, resource use follows a trade-off between rapid resource capture and conservative storage. This worldwide leaf economics spectrum consists of a suite of intercorrelated leaf traits, among which leaf mass per area, LMA, is one of the most fundamental as it indicates the cost of leaf construction and light-interception borne by plants. We conducted a broad-scale analysis of the evolutionary history of LMA across a large dataset of 5401 vascular plant species. The phylogenetic signal in LMA displayed low but significant conservatism, that is, leaf economics tended to be more similar among close relatives than expected by chance alone. Models of trait evolution indicated that LMA evolved under weak stabilizing selection. Moreover, results suggest that different optimal phenotypes evolved among large clades within which extremes tended to be selected against. Conservatism in LMA was strongly related to growth form, as were selection intensity and phenotypic evolutionary rates: woody plants showed higher conservatism in relation to stronger stabilizing selection and lower evolutionary rates compared to herbaceous taxa. The evolutionary history of LMA thus paints different evolutionary trajectories of vascular plant species across clades, revealing the coordination of leaf trait evolution with growth forms in response to varying selection regimes.

  • 40.
    Forslund, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Grazing and geographic range of the Baltic seaweed Fucus radicans (Phaeophyceae)2012In: Marine Biology Research, ISSN 1745-1000, E-ISSN 1745-1019, Vol. 8, no 4, p. 322-330Article in journal (Refereed)
    Abstract [en]

    The range of the recently described seaweed Fucus radicans is limited to the Bothnian Sea and the northern Baltic Sea while the range of the sympatric Fucus vesiculosus extends outside the Baltic Sea. Here we present results from a survey of the distribution and relative abundance of F. radicans and F. vesiculosus and abundance of associated herbivores along the range of F. radicans in Sweden. Both Fucus species were equally common. Herbivores were found in significantly higher numbers on F. radicans. The range of the herbivore Idotea balthica overlaps the southern range of F. radicans and is known to decrease the abundance of fucoids through grazing. We therefore hypothesized that if I. balthica has a preference for F. radicans it could affect the range of F. radicans. To test the preference of I. balthica we performed a bioassay where it had a choice between F. radicans and F. vesiculosus. Another bioassay was performed with the most common herbivore in our survey, Gammarus spp. Both herbivores consumed significantly more F. radicans than F. vesiculosus. Our results indicate that grazing may be an important factor in limiting the southern range of F. radicans along the Swedish coast.

  • 41. Garnier, Eric
    et al.
    Lavorel, Sandra
    Ansquer, P
    Castro, H
    Cruz, P
    Dolezal, J
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Fortunel, C
    Freitas, H
    Golodets, C
    Grigulis, K
    Jouany, C
    Kazakou, E
    Kigel, J
    Kleyer, M
    Lehsten, V
    Leps, J
    Meier, T
    Pakeman, R
    Papadimitriou, M
    Papanastasis, V
    Quested, Helen
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Quetier, F
    Robson, M
    Roumet, C
    Rusch, G
    Skarpe, C
    Sternberg, M
    Theau, J-P
    Thebault, A
    Vile, D
    Zarovali, M
    Assessing the effects of land use change on plant traits, communities and ecosystem functioning in grasslands: A standardized methodology and lessons from an application to 11 European sites2007In: Annals of Botany, Vol. 99, p. 967-985Article in journal (Refereed)
  • 42.
    Glav Lundin, Linnea
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm Univ, Dept Ecol Environm & Plant Sci, Stockholm, Sweden.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    The decline of Gentianella campestris: three decades of population development of an endangered grassland plant in Sweden2021In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 39, no 3, article id e03007Article in journal (Refereed)
    Abstract [en]

    Species-rich semi-natural grasslands are declining all over northern Europe, and many plant species confined to such grasslands are currently under threat. We studied the development of populations of one such species, the field gentian Gentianella campestris, during three decades in the County of Södermanland, south of Stockholm, Sweden. Gentianella campestris is Red Listed as Endangered in Sweden. It is a strict biennial, and as far as known with only a transient seed bank. Large population fluctuations are a characteristic of this species, and its life history makes the species inherently sensitive to factors causing population reductions. We found that the number of sites with G. campestris has declined with over 60% in the last three decades. The total number of flowering individuals also show a strong decreasing trend, although there was an increase the last year (2020) at a few remaining sites. Cessation of grazing management is a major cause of the decline, but populations also disappeared from managed sites. It is possible that the management has been inappropriate, and circumstantial evidence suggests that summer drought might be an additional cause of population decline. Data from 2018, a year with an exceptional summer drought, supports this explanation. A sowing experiment indicated that recruitment of new populations is unlikely in the present-day landscape where most vegetation is unsuitable for G. campestris. Due to the poor prospects for long-term maintenance of grazing management in still remaining semi-natural grasslands, and the decline even at sites with current management, G. campestris faces a risk of becoming regionally extinct within the coming decades.

  • 43. Herben, T
    et al.
    Münzbergová, Z
    Mildén, Mikael
    Stockholm University, Faculty of Science, Department of Botany.
    Ehrlén, Johan
    Cousins, Sara A O
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Longterm spatial dynamics of Succisa pratensis in a changing rural landscape: linking dynamical modelling with historical maps2006In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 94, no 1, p. 131-143Article in journal (Refereed)
    Abstract [en]

    We attempt to explain the current distribution of a long-lived perennial plant, Succisa pratensis, in a rural landscape in southern Sweden by linking its population biology with documented changes in the landscape, using a dynamical, spatially explicit model incorporating population dynamics and spatial spreading of the plant. Changes in the landscape were inferred from historical maps (1850 and 1900) and aerial photographs (1945 and 2001).

     

    We tested whether predictions for the current species distribution are affected by assumptions about its early 19th century distribution, to determine whether recent history and current processes are dominant, and how past landscape changes determine current distributions.

     

    Initial conditions influence predictions of current distribution, suggesting that the current distribution still partly reflects the distribution of the species in the early 19th century. A period of 150 years is too short for Succisa to have spread extensively if dispersal parameters are given realistic values.

     

    Simulations in which present-day land-use patterns were imposed at earlier dates showed that changes in landscape structure over the past 175 years also had a strong effect on the present-day habitat occupancy and population sizes of Succisa.

     

    The dominant process for Succisanow is extinction from marginal habitats. It is therefore likely that the (relatively) high present-day occupation patterns are still due to much larger areas having been available in the past rather than to successful dispersal. Although the species has responded to landscape changes, there is little evidence of population sizes reaching equilibrium.

     

    Our approach shows that the wealth of landscape information available from historical maps can be linked with data on population biology by means of dynamical models that can make predictions about species dynamics.

  • 44. Herzon, Irina
    et al.
    Raatikainen, Kaisa J.
    Helm, Aveliina
    Rūsiņa, Solvita
    Wehn, Solvi
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Semi-natural habitats in the European boreal region: Caught in the socio-ecological extinction vortex?2022In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 51, no 8, p. 1753-1763Article in journal (Refereed)
    Abstract [en]

    We propose to consider semi-natural habitats—hotspots for biodiversity—being caught in a socio-ecological extinction vortex, similar to the phenomenon described for species threatened with extinction. These habitats are essentially socioecological systems, in which socioeconomic drivers are interlinked with ecological processes. We identify four highly interlinked and mutually reinforcing socio-economic processes, pertaining to the importance of semi-natural habitats for (i) agricultural production, (ii) policy, research and development; (iii) vocational education in the fields of agricultural sciences and (iv) public’s experiences with semi-natural habitats. Evidence from six countries in the boreal region demonstrates that recent slowing down or even reversal of two processes are insufficient to stop the extinction vortex phenomenon. We suggest research directions to ascertain the phenomenon, monitor its development and develop proactive actions to weaken the vortex. It is highly plausible that interventions directed at most, if not all, of the key vortex processes are needed to reverse the overall deteriorating trends of a socio-ecological system. 

  • 45.
    Johansson, Veronika A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bahram, M.
    Tedersoo, L.
    Koljalg, U.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Specificity of fungal associations of Pyroleae and Monotropa hypopitys during germination and seedling development2017In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 26, no 9, p. 2591-2604Article in journal (Refereed)
    Abstract [en]

    Mycoheterotrophic plants obtain organic carbon from associated mycorrhizal fungi, fully or partially. Angiosperms with this form of nutrition possess exceptionally small 'dust seeds' which after germination develop 'seedlings' that remain subterranean for several years, fully dependent on fungi for supply of carbon. Mycoheterotrophs which as adults have photosynthesis thus develop from full to partial mycoheterotrophy, or autotrophy, during ontogeny. Mycoheterotrophic plants may represent a gradient of variation in a parasitism-mutualism continuum, both among and within species. Previous studies on plant-fungal associations in mycoheterotrophs have focused on either germination or the adult life stages of the plant. Much less is known about the fungal associations during development of the subterranean seedlings. We investigated germination and seedling development and the diversity of fungi associated with germinating seeds and subterranean seedlings (juveniles) in five Monotropoideae (Ericaceae) species, the full mycoheterotroph Monotropa hypopitys and the putatively partial mycoheterotrophs Pyrola chlorantha, P. rotundifolia, Moneses uniflora and Chimaphila umbellata. Seedlings retrieved from seed sowing experiments in the field were used to examine diversity of fungal associates, using pyrosequencing analysis of ITS2 region for fungal identification. The investigated species varied with regard to germination, seedling development and diversity of associated fungi during juvenile ontogeny. Results suggest that fungal host specificity increases during juvenile ontogeny, most pronounced in the fully mycoheterotrophic species, but a narrowing of fungal associates was found also in two partially mycoheterotrophic species. We suggest that variation in specificity of associated fungi during seedling ontogeny in mycoheterotrophs represents ongoing evolution along a parasitism-mutualism continuum.

  • 46.
    Johansson, Veronika A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bahram, Mohammad
    Tedersoo, Leho
    Kõljalg, Urmas
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Diversity of ectomycorrhizal fungi associated with Pyroleae and  Monotropa hypopitys during germination and seedling developmentManuscript (preprint) (Other academic)
  • 47.
    Johansson, Veronika A.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Remnant Populations and Plant Functional Traits in Abandoned Semi-Natural Grasslands2011In: Folia Geobotanica, ISSN 1211-9520, E-ISSN 1874-9348, Vol. 46, no 2-3, p. 165-179Article in journal (Refereed)
    Abstract [en]

    Although semi-natural grasslands in Europe are declining there is often a time delay in the local extinction of grassland species due to development of remnant populations, i.e., populations with an extended persistence despite a negative growth rate. The objectives of this study were to examine the occurrence of remnant populations after abandonment of semi-natural grasslands and to examine functional traits of plants associated with the development of remnant populations. We surveyed six managed semi-natural grasslands and 20 former semi-natural grasslands where management ceased 60-100 years ago, and assessed species response to abandonment, assuming a space-for-time substitution. The response of species was related to nine traits representing life cycle, clonality, leaf traits, seed dispersal and seed mass. Of the 67 species for which data allowed analysis, 44 species declined after grassland abandonment but still occurred at the sites, probably as remnant populations. Five traits were associated with the response to abandonment. The declining but still occurring species were characterized by high plant height, a perennial life form, possession of a perennial bud bank, high clonal ability, and lack of dispersal attributes promoting long-distance dispersal. Traits allowing plants to maintain populations by utilizing only a part of their life cycle, such as clonal propagation, are most important for the capacity to develop remnant populations and delay local extinction. A considerable fraction of the species inhabiting semi-natural grasslands maintain what is most likely remnant populations after more than 60 years of spontaneous succession from managed semi-natural grasslands to forest.

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  • 48.
    Johansson, Veronika A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Recruitment limitation, germination of dust seeds, and early development of underground seedlings in six Pyroleae species2013In: Botany, ISSN 1916-2790, E-ISSN 1916-2804, Vol. 91, no 1, p. 17-24Article in journal (Refereed)
    Abstract [en]

    We investigated recruitment of six mixotrophic Pyroleae species in relation to soil and adult presence. Pyroleae have dust seeds containing minimal nutrient reserves, and subterranean seedlings are mycoheterotrophic needing fungal hosts for germination and development. Germination and seedling development were studied by retrieving seed bags that had been placed within plots with adults present and at unoccupied control plots. There are two main alternatives to what limits recruitment of plants, seed limitation or microsite limitation. Results suggested that a combination of microsite and seed limitation was important for all investigated species. Microsite availability was the main limiting factor for Chimaphila umbellata (L.) W. P. C. Barton, Orthilia secunda (L.) House, and Pyrola chlorantha Sw., whereas seed availability was the main limiting factor for Pyrola minor L. For Moneses uniflora L. A. Gray and Pyrola rotundifolia L., it was not clear whether microsite or seed limitation dominated. Growth of seedlings responded positively to adult presence (O. secunda and P. minor), whereas others were negatively affected (M. uniflora and P. chlorantha). Increased levels of soil nutrients (N and P) had a negative effect on seedling growth in C. umbellata and P. chlorantha. These results provide the first evidence of the importance of microsite and seed limitation for germination and development of seedlings of Pyroleae species.

  • 49.
    Johansson, Veronika A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Mikusinska, Anna
    Ekblad, Alf
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Partial mycoheterotrophy in Pyroleae: nitrogen and carbon stable isotope signatures during development from seedling to adult2015In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 177, no 1, p. 203-211Article in journal (Refereed)
    Abstract [en]

    Mycoheterotrophic plants (MHP) are divided into non-photosynthesizing full MHP and green-leaved partial or initial MHP. We investigated 13C and 15N isotope enrichment in five putatively partial MHP species in the tribe Pyroleae (Ericaceae): Chimaphila umbellata, Moneses uniflora, Orthilia secunda, Pyrola chlorantha and Pyrola minor, sampled from forest sites on Öland, Sweden. For M. uniflora and P. chlorantha, we investigated isotope signatures of subterranean seedlings (which are mycoheterotrophic), to examine how the use of seedlings instead of full MHP species (Hypopitys monotropa) as reference species affects the assessment of partial mycoheterotrophy. Our main findings were as follows: (1) All investigated Pyroleae species were enriched in 15N compared to autotrophic reference plants. (2) significant fungal-derived C among the Pyroleae species was found for O. secunda and P. chlorantha. For the remaining species of C. umbellata, M. uniflora and P. minor, isotope signatures suggested adult autotrophy. (3) C and N gains, calculated using seedlings as a full MHP reference, yielded qualitatively similar results as when using H. monotropa as a reference. However, the estimated differences in C and N gains became larger when using seedlings as an MHP reference. (4) A previously unknown interspecific variation in isotope signature occurs during early ontogeny, from seed production to developing seedlings. Our findings suggest that there is a variation among Pyroleae species concerning partial mycoheterotrophy in adults. Adult autotrophy may be most common in Pyroleae species, and these species may not be as dependent on fungal-derived nutrients as some green orchids.

  • 50.
    Johansson, Veronika A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Mueller, Gregor
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Dust seed production and dispersal in Swedish Pyroleae species2014In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 32, no 2, p. 209-214Article in journal (Refereed)
    Abstract [en]

    Dust seeds are the smallest seeds in angiosperms weighing just about a few micrograms. These seeds are characteristic of most orchids, and several studies have been performed on seed features, fecundity and dispersal of orchid dust seeds. In this study we examine seed features, seed production and seed dispersal in another plant group with dust seeds, the Pyroleae (Monotropoideae, Ericaceae), focusing on six species: Pyrola chlorantha, P. minor, P. rotundifolia, Chimaphila umbellata, Moneses uniflora and Orthilia secunda. Seed production per capsule among these species was in the range between ca 1000 and 7800, and seed production per capsule bearing shoot was in the range between ca 7000 and 60 000. Combining our results with published information on pollen-ovule ratios suggests that these Pyroleae species have a generally efficient pollination system. The most fecund species was P. minor, the only species among the investigated that is probably largely self-pollinating. The investigated Pyroleae species have a seed production comparable to the less fecund orchid species. We studied seed dispersal in the field in one of the species, P. chlorantha. Despite the extremely small and potentially buoyant seeds, the vast majority of seeds are deposited close to the seed source, within a few meters. Further studies on the recruitment ecology of the investigated Pyroleae species are currently under way.

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