Skip to main content
    • Aa
    • Aa

Passive Reestablishment of Riparian Vegetation Following Removal of Invasive Knotweed (Polygonum)

  • Shannon M. Claeson (a1) and Peter A. Bisson (a1)

Japanese knotweed and congeners are invasive to North America and Europe and spread aggressively along rivers establishing dense monotypic stands, thereby reducing native riparian plant diversity, structure, and function. Noxious weed control programs attempt to eradicate the knotweed with repeated herbicide applications under the assumption that the system will recover to a native assemblage which will inhibit future invasions. However, eradication efficacy studies typically only measure the amount of knotweed reduced, not the reestablished species diversity or plant origins. For a community scale efficacy study, we measured vascular plant species diversity and cover in riparian areas along five rivers in Washington State, 3 to 6 years after Bohemian knotweed was initially treated with herbicide. Plant species composition was compared between riparian sites treated to remove knotweed and reference sites where knotweed was absent. Sites where knotweed had been removed had significantly more exotic species and vegetative cover than reference sites; however, native species richness and cover were greater in reference sites and areas with more overstory vegetation. The native plants observed were primarily shade tolerant and perennial, as opposed to many of the exotics, which were shade-intolerant annuals. In general, reestablishment of native and exotic vegetation was not related to pretreatment knotweed stem count, size of the invaded area, or timing of herbicide application. However, residual native tree cover was negatively correlated with initial knotweed stem count. Monitoring the success of restoration objectives (e.g., native plant reestablishment or increased species diversity) and characterizing associated habitat features following knotweed eradication will help in the development of site-specific protocols for successful plant community scale restoration.

Corresponding author
Corresponding author's E-mail:
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

U. B. Bashtanova , K. P. Beckett , and T. J. Flowers 2009. Review: Physiological approaches to the improvement of chemical control of Japanese knotweed (Fallopia japonica). Weed Sci. 57:584592.

J. L. Butler and S. D. Wacker 2010. Lack of native vegetation recovery following biological control of leafy spurge. Rangeland Ecol. Manage. 63:553563.

Y. A. Cuevas and S. M. Zalba 2010. Recovery of native grasslands after removing invasive pines. Restor. Ecol. 18:711719.

N. Dassonville , N. Guillaumaud , F. Piola , P. Meerts , and F. Poly 2011. Niche construction by the invasive Asian knotweeds (species complex Fallopia): impact on activity, abundance and community structure of denitrifiers and nitrifiers. Biol. Invasions 13:11151133.

M. A. Davis , J. P. Grime , and K. Thompson 2000. Fluctuating resources in plant communities: a general theory of invasibility. J. Ecol. 88:528534.

M. Dufrene and P. Legendre 1997. Species assemblages and indicator species: the need for a flexible asymmetrical approach. Ecol. Monogr. 67:345366.

J. L. Funk and S. McDaniel 2010. Altering light availability to restore invaded forest: the predictive role of plant traits. Restor. Ecol. 18:865872.

E. Gerber , C. Krebs , C. Murrell , M. Moretti , R. Rocklin , and U. Schaffner 2008. Exotic invasive knotweeds (Fallopia spp.) negatively affect native plant and invertebrate assemblages in European riparian habitats. Biol. Conserv. 141:646654.

S. V. Gregory , F. J. Swanson , W. A. McKee , and K. W. Cummins 1991. An ecosystem perspective of riparian zones. Bioscience 41:540551.

W. G. Hood and R. J. Naiman 2000. Vulnerability of riparian zones to invasion by exotic vascular plants. Plant Ecol. 148:105114.

C. R. Hupp and W. R. Osterkamp 1996. Riparian vegetation and fluvial geomorphic processes. Geomorphology 14:277295.

A. Lecerf , D. Patfield , A. Boiche , M. P. Riipinen , E. Chauvet , and M. Dobson 2007. Stream ecosystems respond to riparian invasion by Japanese knotweed (Fallopia japonica). Can. J. Fish. Aquat. Sci. 64:12731283.

T. K. Magee , P. L. Ringold , and M. A. Bollman 2008. Alien species importance in native vegetation along wadeable streams, John Day River basin, Oregon, USA. Plant Ecol. 195:287307.

C. D. McClain , K. D. Holl , and D. M. Wood 2011. Successional models as guides for restoration of riparian forest understory. Restor. Ecol. 19:280289.

R. J. Naiman , R. E. Bilby , and P. A. Bisson 2000. Riparian ecology and management in the Pacific coastal rain forest. Bioscience 50:9961011.

A.-M. Planty-Tabacchi , E. Tabacchi , R. J. Naiman , C. M. DeFarrari , and H. Decamps 1996. Invasibility of species-rich communities in riparian zones. Conserv. Biol. 10:598607.

D. M. Richardson , P. M. Holmes , K. J. Esler , S. M. Galatowitsch , J. C. Stromberg , S. P. Kirkman , P. Pysek , and R. J. Hobbs 2007. Riparian vegetation: Degradation, alien plant invasions, and restoration prospects. Divers. Distrib. 13:575592.

E. W. Seabloom , E. T. Borer , V. L. Boucher , R. S. Burton , K. L. Cottingham , L. Goldwasser , W. K. Gram , B. E. Kendall , and F. Micheli 2003. Competition, seed limitation, disturbance, and reestablishment, of California native annual forbs. Ecol. Appl. 13:575592.

K. Shea and P. Chesson 2002. Community ecology theory as a framework for biological invasions. Trends Ecol. Evol. 17:170176.

J. M. Stevens and J. S. Fehmi 2011. Early establishment of a native grass reduces the competitive effect of a non-native grass. Restor. Ecol. 19:399406.

B. W. Sweeney , S. J. Czapka , and T. Yerkes 2002. Riparian forest restoration: Increasing success by reducing plant competition and herbivory. Restor. Ecol. 10:392400.

L. S. Urgenson , S. H. Reichard , and C. B. Halpern 2009. Community and ecosystem consequences of giant knotweed (Polygonum sachalinense) invasion into riparian forests of western Washington, USA. Biol. Conserv. 142:15361541.

L. S. Urgenson , S. H. Reichard , and C. B. Halpern 2012. Multiple competitive mechanisms underlie the effects of a strong invader on early- to late-seral tree seedlings. J. Ecol. DOI: 10.1111/j.1365-2745.2012.01995.x.

S. Vanderhoeven , N. Dassonville , and P. Meerts 2005. Increased topsoil mineral nutrient concentrations under exotic invasive plants in Belgium. Plant Soil 275:169179.

D. I. Warton and F. K. C. Hui 2011. The arcsine is asinine: the analysis of proportions in ecology. Ecology 92:310.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Invasive Plant Science and Management
  • ISSN: 1939-7291
  • EISSN: 1939-747X
  • URL: /core/journals/invasive-plant-science-and-management
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 0
Total number of PDF views: 5 *
Loading metrics...

Abstract views

Total abstract views: 21 *
Loading metrics...

* Views captured on Cambridge Core between 20th January 2017 - 28th June 2017. This data will be updated every 24 hours.