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Jakobsson, Anna
Publications (6 of 6) Show all publications
Jakobsson, A., Padrón, B. & Ågren, J. (2015). Distance-dependent effects of invasive Lupinus polyphyllus on pollination and reproductive success of two native herbs. Basic and Applied Ecology, 16(2), 120-127.
Open this publication in new window or tab >>Distance-dependent effects of invasive Lupinus polyphyllus on pollination and reproductive success of two native herbs
2015 (English)In: Basic and Applied Ecology, ISSN 1439-1791, E-ISSN 1618-0089, Vol. 16, no 2, 120-127 p.Article in journal (Refereed) Published
Abstract [en]

A comprehensive understanding of the effects of invasive plants on native species requires identification of both the mechanisms of interaction and the spatial scale over which they act. Indirect interactions involving mobile organisms such as pollinators are likely to be scale-dependent, yet most studies examining effects of invasive species on pollination of native plants have considered effects across a single distance between interacting species. We examined the effects of the invasive herb Lupinus polyphyllus on pollination of two native herbs using multiple distances between the invasive and the natives. We recorded pollinator visitation and seed production in the native herbs Lotus corniculatus and Lychnis viscaria at 0, 5 m or 200 m away from L. polyphyllus. To reduce the influence of confounding factors, we used experimentally established populations of the invasive and potted individuals of the natives. In the immediate vicinity to L. polyphyllus, visitation to L. corniculatus was higher than 200 m away, and seed production per flower was higher than 5 m and 200 m away. In L. viscaria, bumblebee visitation was higher adjacent to L. polyphyllus than 5 m and 200 m away, but total pollinator visitation and reproductive success did not vary with distance. The results indicate that L. polyphyllus facilitates pollination of the native plants, and that this occurs at a very local spatial scale as effects dropped off already at a distance of 5 m. Presence of L. polyphyllus could benefit both pollinators and pollination of native herbs, and these positive effects should be considered along with likely negative effects due to resource competition. Moreover, the results illustrate the necessity to consider scale-dependent effects when assessing the impact of invasive flowering plants on native pollination interactions.

Keyword
Fecundity, Invasion, Lotus corniculatus, Lychnis viscaria, Pollination, Spatial scale
National Category
Ecology Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-251576 (URN)10.1016/j.baae.2014.12.005 (DOI)000350858900004 ()
Available from: 2015-04-21 Created: 2015-04-21 Last updated: 2017-12-04Bibliographically approved
Ekroos, J., Jakobsson, A., Wideen, J., Herbertsson, L., Rundlof, M. & Smith, H. G. (2015). Effects of landscape composition and configuration on pollination in a native herb: a field experiment. Oecologia, 179(2), 509-518.
Open this publication in new window or tab >>Effects of landscape composition and configuration on pollination in a native herb: a field experiment
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2015 (English)In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 179, no 2, 509-518 p.Article in journal (Refereed) Published
Abstract [en]

Bumble bee abundance in agricultural landscapes is known to decrease with increasing distance from seminatural grasslands, but whether the pollination of bumble-bee-pollinated wild plants shows a similar pattern is less well known. In addition, the relative effects of landscape composition (landscape heterogeneity) and landscape configuration (distance from seminatural grassland) on wild plant pollination, and the interaction between these landscape effects, have not been studied using landscape-level replication. We performed a field experiment to disentangle these landscape effects on the pollination of a native herb, the sticky catchfly (Lychnis viscaria), while accounting for the proportion of oilseed rape across landscapes and the local abundance of bee forage flowers. We measured pollen limitation (the degree to which seed set is pollen-limited), seed set, and seed set stability using potted plants placed in landscapes that differed in heterogeneity (composition) and distance from seminatural grassland (configuration). Pollen limitation and seed set in individual plants did not respond to landscape composition, landscape configuration, or proportion of oilseed rape. Instead, seed set increased with increasing local bee forage flower cover. However, we found within-plant variability in pollen limitation and seed set to increase with increasing distance from seminatural pasture. Our results suggest that average within-plant levels of pollen limitation and seed set respond less swiftly than the within-plant variability in pollen limitation and seed set to changes in landscape configuration. Although landscape effects on pollination were less important than predicted, we conclude that landscape configuration and local habitat characteristics play larger roles than landscape composition in the pollination of L. viscaria.

Keyword
Pollen limitation, Source habitats, Landscape heterogeneity, Seed set, Sexual reproduction
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-264614 (URN)10.1007/s00442-015-3370-y (DOI)000361472300018 ()26085467 (PubMedID)
Funder
EU, FP7, Seventh Framework Programme, 244090Swedish Research Council Formas
Available from: 2015-10-27 Created: 2015-10-15 Last updated: 2017-12-01Bibliographically approved
Jakobsson, A. & Ågren, J. (2014). Distance to semi-natural grassland influences seed production of insect-pollinated herbs. Oecologia, 175(1), 199-208.
Open this publication in new window or tab >>Distance to semi-natural grassland influences seed production of insect-pollinated herbs
2014 (English)In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 175, no 1, 199-208 p.Article in journal (Refereed) Published
Abstract [en]

Marginal grassland fragments, such as road verges and field margins, may act as important supplemental habitats for grassland plants in the modern agricultural landscape. However, abundance of pollinators in such fragments has been found to decline with distance to larger natural and semi-natural habitats, and this could have corresponding effects on plant pollination. In this study, we performed a field experiment on road verges with three insect-pollinated grassland herbs to examine the relationship between distance to semi-natural grassland and plant reproductive success in two landscapes with contrasting farming intensities. In Lychnis viscaria and Lotus corniculatus, seed production tended to decrease with increasing distance to semi-natural grassland, but only in the landscape with high farming intensity. Seed production in Armeria maritima spp. maritima decreased with distance in both landscapes. Although many studies have investigated effects of natural habitat on crop pollination, little is known about the impact on pollination in native plants. The results from this study indicate that management of semi-natural grasslands improves not only biodiversity within the actual grassland but also pollination of native plants in the surrounding agricultural landscape.

Keyword
Fecundity, Landscape, Pollination service, Self-incompatibility
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-225007 (URN)10.1007/s00442-014-2904-z (DOI)000334691600018 ()
Available from: 2014-05-26 Created: 2014-05-26 Last updated: 2017-12-05Bibliographically approved
Jakobsson, A. & Padron, B. (2014). Does the invasive Lupinus polyphyllus increase pollinator visitation to a native herb through effects on pollinator population sizes?. Oecologia, 174(1), 217-226.
Open this publication in new window or tab >>Does the invasive Lupinus polyphyllus increase pollinator visitation to a native herb through effects on pollinator population sizes?
2014 (English)In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 174, no 1, 217-226 p.Article in journal (Refereed) Published
Abstract [en]

Invasive plants may compete with native species for abiotic factors as light, space and nutrients, and have also been shown to affect native pollination interactions. Studies have mainly focused on how invasive plants affect pollinator behaviour, i.e. attraction of pollinators to or away from native flowers. However, when an invasive plant provides resources utilized by native pollinators this could increase pollinator population sizes and thereby pollination success in natives. Effects mediated through changes in pollinator population sizes have been largely ignored in previous studies, and the dominance of negative interactions suggested by meta-analyses may therefore be biased. We investigated the impact of the invasive Lupinus polyphyllus on pollination in the native Lotus corniculatus using a study design comparing invaded and uninvaded sites before and after the flowering period of the invasive. We monitored wild bee abundance in transects, and visit rate and seed production of potted Lotus plants. Bumblebee abundance increased 3.9 times in invaded sites during the study period, whereas it was unaltered in uninvaded sites. Total visit rate per Lotus plant increased 2.1 times in invaded sites and decreased 4.4 times in uninvaded sites. No corresponding change in seed production of Lotus was found. The increase in visit rate to Lotus was driven by an increase in solitary bee visitation, whereas mainly bumblebees were observed to visit the invasive Lupinus. The mechanism by which the invasive increases pollinator visit rates to Lotus could be increased availability of other flower resources for solitary bees when bumblebees forage on Lupinus.

Keyword
Pollination, Wild bees, Flower resources, Seed production, Agricultural landscape
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-218592 (URN)10.1007/s00442-013-2756-y (DOI)000329624300021 ()
Available from: 2014-02-13 Created: 2014-02-13 Last updated: 2017-12-06Bibliographically approved
Lazaro, A., Jakobsson, A. & Totland, O. (2013). How do pollinator visitation rate and seed set relate to species' floral traits and community context?. Oecologia, 173(3), 881-893.
Open this publication in new window or tab >>How do pollinator visitation rate and seed set relate to species' floral traits and community context?
2013 (English)In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 173, no 3, 881-893 p.Article in journal (Refereed) Published
Abstract [en]

Differences among plant species in visitation rate and seed set within a community may be explained both by the species' floral traits and the community context. Additionally, the importance of species' floral traits vs. community context on visitation rate and seed set may vary among communities. In communities where the pollinator-to-flower ratio is low, floral traits may be more important than community context, as pollinators may have the opportunity to be choosier when visiting plant species. In this study we investigated whether species' floral traits (flower shape, size and number, and flowering duration) and community context (conspecific and heterospecific flower density, and pollinator abundance) could explain among-species variation in visitation rate and seed set. For this, we used data on 47 plant species from two Norwegian plant communities differing in pollinator-to-flower ratio. Differences among species in visitation rate and seed set within a community could be explained by similar variables as those explaining visitation rate and seed set within species. As expected, we found floral traits to be more important than community context in the community with a lower pollinator-to-flower ratio; whereas in the community with a higher pollinator-to-flower ratio, community context played a bigger role. Our study gives significant insights into the relative importance of floral traits on species' visitation rate and seed set, and contributes to our understanding of the role of the community context on the fitness of plant species.

Keyword
Conspecific flower density, Display traits, Heterospecific flower density, Inter-specific comparison, Pollinator abundance
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-211017 (URN)10.1007/s00442-013-2652-5 (DOI)000325819700023 ()
Available from: 2013-11-20 Created: 2013-11-19 Last updated: 2017-12-06Bibliographically approved
Traveset, A. & Jakobsson, A. (2007). Ecology of plant reproduction: Mating systems and pollination. In: Functional Plant Ecology: . .
Open this publication in new window or tab >>Ecology of plant reproduction: Mating systems and pollination
2007 (English)In: Functional Plant Ecology, 2007Chapter in book (Refereed)
Identifiers
urn:nbn:se:uu:diva-14508 (URN)
Available from: 2008-01-30 Created: 2008-01-30 Last updated: 2016-04-22
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