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ARS Home » Plains Area » Sidney, Montana » Northern Plains Agricultural Research Laboratory » Pest Management Research » Research » Publications at this Location » Publication #335947
Title: Invasive Russian knapweed (Acroptilon repens) creates large patches almost entirely by rhizomic growth

Author
item Gaskin, John
item LITTLEFIELD, JEFFREY - Montana State University

Submitted to: Invasive Plant Science and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2016
Publication Date: 5/5/2017
Citation: Gaskin, J.F., Littlefield, J.L. 2017. Invasive Russian knapweed (Acroptilon repens) creates large patches almost entirely by rhizomic growth. Invasive Plant Science and Management. doi:10.1017/inp.2017.9.

Interpretive Summary: Russian knapweed is an invasive weed in North America that can spread by both seed and root growth leading to new shoots, but it is unclear which method is most common in local invasions. We used DNA collected from shoots in two discreet patches of Russian knapweed at each of three locations in Montana, USA. Out of the 174 shoots collected we found nine genotypes. Three out of the six patches were a single genotype, and the other three patches each had one rare genotype. No genotypes were shared between patches. The maximum diameter of a single individual was 56.5 m. These results indicate that at the local scale patch expansion is almost entirely by roots that spread and develop shoots. At the long-distance scale spread is by seed. This informs land managers that controlling seed development may be effective at stopping long distance dispersal, but may not affect expansion of existing patches.

Technical Abstract: Russian knapweed is an outcrossing perennial invasive weed in North America that can spread by both seed and horizontal rhizome growth leading to new shoots. The predominant mode of spread at the local and long-distance scales has not been quantitatively researched. We used Amplified Fragment Length Polymorphisms (AFLPs) of DNA collected from shoots in two discreet patches of Russian knapweed at each of three locations in Montana, USA. Out of the 174 shoots collected we found nine AFLP genotypes. Three out of the six patches were monotypic, and the other three patches each had one rare genotype. No genotypes were shared between patches. The maximum diameter of a genet was 56.5 m. These results indicate that at the local scale patch expansion is almost entirely by rhizomes that spread and develop shoots. At the long-distance scale spread is by seed. This informs land managers that controlling seed development may be effective at stopping long distance dispersal, but may not affect expansion of existing patches.