Invasiveness Ranking System for Non-Native Plants of Alaska

Role of anthropogenic and natural disturbance in0establishment (0–5)European stickseed typically establishes in disturbed areasand may become abundant in overgrazed pastures (Royer andDickinson 1999). In Denali National Park it was found only onsites disturbed within the last 3 years or sites regularly disturbed(Densmore et al. 2001).Current global distribution (0–5) 5European stickseed is native to the eastern Mediterranean region.Its modern-day distribution extends from Europe (includingthe North Pacific islands of Spitsbergen and Iceland) to NorthAmerica, Asia and Japan between approximately 30° and 70°Nlatitude. European stickseed occurs in comparable southernhemisphere regions in South Africa and Australia (Frick 1984). Itis known from arctic Norway (Lid and Lid 1994).Extent of the species U.S. range and/or occurrence of5formal state or provincial listing (0–5)European stickseed has been reported from every Canadianprovince and nearly all American states (Royer and Dickinson1999, USDA 2002). It is declared a federal noxious weed inCanada. This species is a restricted noxious weed in Alaska(Alaska Administrative Code 1987, Royer and Dickinson 1999).Total for Ecological Amplitude and Distribution 17/25Feasibility of ControlScoreSeed banks (0–3) 2Although 95% of European stickseed seedlings emerge in the firstyear, seedling emergence may continue for 4 years (Chepil 1946).Vegetative regeneration (0–3) 1Mowing or grazing frequently results in forming numerousaxillary inflorescences produced below the injury, which canincrease seed production (Frick 1984).Level of effort required (0–4) 2European stickseed is easily pulled up by hand, although severalweedings may be necessary to eliminate population (Densmore etal. 2001). In cultivated crops it may be controlled by a wide rangeof commonly used herbicides. Mowing or grazing is usually noteffective (Frick 1984).Total for Feasibility of Control 5/10Total score for 4 sections 44/100§B-60