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Fallopia x bohemica - Hybrid knotweed

French name:  Renouée de bohème
Family: Polygonaceae
Group: Vascular plants
Origin: Asia
Habitat: terrestrial
Introduction:  agri- and horticulture
ISEIA Score : 12
Naturalization in Belgium
First observation in the wild: 1924
Invasion stage: spread
Spatial distribution: restricted
Reproduction in the wild: yes
Dispersion potential: high
Natural habitats: high
More on invasiveness: As other Asiatic knotweeds, Fallopia x bohemica colonises a wide range of environments, with a predilection for moist and nitrogen-rich soils. It prefers sunny places or semi-shaded habitats. This pioneer plant proliferates both in ruderal and semi-natural habitats, including riparian areas and open forests. Stem and rhizomes may easily split in small pieces; fragments are able to regenerate a plant, provided a node is present. Hybrid knotweed may produce seeds but seedling establishment is usually inefficient due to frost sensitivity. Transport of garden waste and soil contaminated with rhizomes are the major dispersal modes. Where the plant is widely consolidated on river banks it is also spread by floods and can easily colonise downstream.
Distribution in Belgium
Established populations
absent from district
isolated populations (1-5 localities per district)
widespread (>5 localities per district)
Endangered areas
low risk
medium risk
high risk

Endangered Natura 2000 habitats ():
grasslands: 64306510
forest habitats: 91E0*91F0
Impacts on Species
Predation / Herbivory: low
Competition: high
Disease transmission: low
Genetic effects: low
Impacts on Ecosystems
Nutrient cycling: likely
Physical alteration: high
Natural successions: high
Food web alteration: low
More on impacts: Fallopia x bohemica exhibits hybrid vigour and is reputed to be more invasive than the 2 parents, F. japonica and F. sachalinensis. It typically form very dense stands, excluding native vegetation and prohibiting regeneration. It reduces plant and invertebrate species diversity, alters habitat for wildlife and change ligth and energy conditions of the ecosystem. Once stands become established, they are extremely persistent and difficult to remove. Its development can favour river bank erosion during the winter.
Data Source & References
Authors: Branquart Etienne, Vanderhoeven Sonia, Van Landuyt Wouter, Van Rossum Fabienne, Verloove Filip
Published on:  16 December 2010
Last update:  16 December 2010
Alberternst, B. & Böhmer, H.J. (2006)
Invasive alien species fact sheet, Fallopia japonica.
From online database of the North European and Baltic network on invasive alien species (NOBANIS).
Bimova, K., Mandak, B. & Kasparova, I. (2004)
How does Reynoutria invasion fit the various theories of invasibility?
Journal of Vegetation Science 15(4): 495–504.
Bímová, K., Mandák, B. & Kašparová, I. (2004)
How does Reynoutria invasion fit the various theories of invasibility?
Journal of Vegetation Science 15(4): 495–504.
Gammon, M. & Kessili, R. (2009)
Hybrids spreading faster than parents. A comparison of vegetative and reproductive success of the invasive species Fallopia japonica, F. sachalinensis and F. x bohemica (Polygonaceae) in a common garden experiment.
Preslia 76: 15 - 64.
Gerber, E., Krebs, C., Murrell, C., Moretti, M., Rocklin, R. & Schaffner, U. (2008)
Exotic invasive knotweeds (Fallopia spp.) negatively affect native plant and invertebrate assemblages in European riparian habitats.
Biological Conservation 141: 646-654.
Hart, M.L., Bailey, J.P., Hollingsworth,P.M. & Watson, K.J. (1997)
Sterile species and fertile hybrids of Japanese Knotweeds along the River Kelvin.
Glasgow Naturalist 23: 18 – 22.
Hejda, M., Pysek, P. & Jarosik, V. (2009)
Impact of invasive plants on the species richness, diversity and composition of invaded communities.
Journal of Ecology 97: 393–403.
Kappes, H., Lay, R. & Topp, W. (2007)
Changes in different trophic levels of litter-dwelling macrofauna associated with giant knotweed invasion.
Ecosystems 10: 737-744.
Krebs, C., Mahy, G., Matthies, D., Schaffner, U.,Tiébré, M.-S. & Bizoux, J.-P. (2009)
Taxa distribution and RAPD markers indicate different origin and regional differentiation of hybrids in the invasive Fallopia complex in central-western Europe.
Plant Biology
Lambinon, J., Delvosalle, L. & Duvigneaud, J. (2004)
Nouvelle fore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des régions voisines.
Editions du Patrimoine du Jardin botanique national de Belgique, Meise.
Muller, S. (2004)
Plantes invasives en France : état des connaissances et propositions d'actions.
Publication scientifique du Museum d'Histoire naturelle, Patrimoines naturels n°62.
Murrell, C., Gerber, E., Krebs, C., Parepa, M., Schaffner, U. & Bossdorf, O. (2011)
Invasive knotweed affects native plants through allelopathy.
American Journal of Botany 98(1): 38–43.
Siemens, T.J. & Blossey, B. (2007)
An evaluation of mechanisms preventing growth and survival of two native species in invasive Bohemian knotweed (Fallopia xbohemica, Polygonaceae).
American Journal of Botany 94: 776-783.
Tiébré, M.-S., Bizoux, J.-P., Hardy, O.J., Bailey, J.P. & Mahy, G. (2007)
Hybridization and morphogenetic variation in the invasive alien Fallopia (Polygonaceae) complex in Belgium.
American Journal of Botany 94: 1900–1910.
Tiébré, M.-S., Vanderhoeven, S., Saad, L. & Mahy, G. (2007)
Hybridization and sexual reproduction in the invasive alien Fallopia (Polygonaceae) complex in Belgium.
Annals of Botany 99: 193–203.
Van Landuyt, W., Hoste, I., Vanhecke, L., Van den Bremt, P. Vercruysse, W. & De Beer, D. (2006)
Atlas van de Flora van Vlaanderen en het Brussels gewest.
Nationale Plantentuin en het Instituut voor Natuur- en Bosonderzoek i.s.m. Flo.Wer vzw.
Verloove, F. (2006)
Catalogue of the Neophytes in Belgium (1800-2005).
Scripta Botanica Belgica 39, 89 pp.
Weber, E. & Gut, D. (2004)
Assessing the risk of potentially invasive plant species in central Europe.
Journal for Nature Conservation12: 171-179.
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