Effective Long-Distance Pollen Dispersal in Centaurea jacea
Open Access
- 25 August 2009
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 4 (8), e6751
- https://doi.org/10.1371/journal.pone.0006751
Abstract
Agri-environment schemes play an increasingly important role for the conservation of rare plants in intensively managed agricultural landscapes. However, little is known about their effects on gene flow via pollen dispersal between populations of these species. In a 2-year experiment, we observed effective pollen dispersal from source populations of Centaurea jacea in restored meadows, the most widespread Swiss agri-environment scheme, to potted plants in adjacent intensively managed meadows without other individuals of this species. Potted plants were put in replicated source populations at 25, 50, 100 m and where possible 200 m distance from these source populations. Pollen transfer among isolated plants was prevented by temporary bagging, such that only one isolated plant was accessible for flower visitors at any one time. Because C. jacea is self-incompatible, seed set in single-plant isolates indicated insect mediated effective pollen dispersal from the source population. Seed set was higher in source populations (35.7±4.4) than in isolates (4.8±1.0). Seed set declined from 18.9% of that in source populations at a distance of 25 m to 7.4% at 200 m. At a distance of 200 m seed set was still significantly higher in selfed plants, indicating long-distance effective pollen dispersal up to 200 m. Analyses of covariance suggested that bees contributed more than flies to this long-distance pollen dispersal. We found evidence that pollen dispersal to single-plant isolates was positively affected by the diversity and flower abundance of neighboring plant species in the intensively managed meadow. Furthermore, the decline of the dispersal was less steep when the source population of C. jacea was large. We conclude that insect pollinators can effectively transfer pollen from source populations of C. jacea over at least 200 m, even when “recipient populations” consisted of single-plant isolates, suggesting that gene flow by pollen over this distance is very likely. Source population size and flowering environment surrounding recipient plants appear to be important factors affecting pollen dispersal in C. jacea. It is conceivable that most insect-pollinated plants in a network of restored sites within intensively managed grassland can form metapopulations, if distances between sites are of similar magnitude as tested here.This publication has 49 references indexed in Scilit:
- Long‐term observation of a pollination network: fluctuation in species and interactions, relative invariance of network structure and implications for estimates of specializationEcology Letters, 2008
- Quantifying the impact of environmental factors on arthropod communities in agricultural landscapes across organizational levels and spatial scalesJournal of Applied Ecology, 2005
- Genetic Effects of Habitat Fragmentation on Common Species of Swiss Fen MeadowsConservation Biology, 2004
- Effects of habitat fragmentation on population structure and fitness components of the wetland specialist Swertia perennis L. (Gentianaceae)Basic and Applied Ecology, 2002
- Effects of population size and pollen diversity on reproductive success and offspring size in the narrow endemic Cochlearia bavarica (Brassicaceae)American Journal of Botany, 2002
- Long-distance pollinator flights and pollen dispersal between populations of Delphinium nuttallianumOecologia, 2001
- Effects of elevated CO 2 on flowering phenology and nectar production of nectar plants important for butterflies of calcareous grasslandsOecologia, 1998
- Gene Flow in Chamaecrista fasciculata (Leguminosae) I. Gene DispersalEvolution, 1991
- Pollen and Gene Dispersal: The Influences of Competition for PollinationEvolution, 1985
- Recherches biosystématiques sur la Section Jacea Cass. et quelques sections voisines du genre Centaurea L. en France et dans les régions limitrophesFeddes Repertorium, 1972