Invasiveness Ranking System for Non-Native Plants of Alaska

Spread by humans (0–3) 3Bird vetch was first planted in Alaska in 1909. Later it was plantedat the Fairbanks and Matanuska experiment stations where itwas evaluated for forage (Klebesadel 1980). It can be introducedwith topsoil (Densmore et al. 2001). Additionally, it can spreadalong roads on cars and heavy equipment (J. Conn pers. obs.,M. Shephard pers. obs.).Allelopathic (0–2) 0This species is not allelopathic (USDA 2002).Competitive Ability (0–3) 2Bird vetch has the ability to fix nitrogen (USDA 2002) andcompetes for resources with other species.Thicket-forming/Smothering growth form (0–2) 2Bird vetch overgrows herbaceous vegetation and climbs “kudzustyle”up and over shrubs such as alder and willow as well as smallspruce trees (Densmore et al. 2001).Germination requirements (0–3) 2Vicia cracca usually establishes in disturbed areas, includingthose with well-developed vegetation (Densmore et al. 2001).The seeds can easy germinate in wide range of conditions withoutscarification (J. Snyder unpubl. data).Other invasive species in the genus (0–3) 3Vicia benghalensis L. V. disperma DC., V. hirsuta (l.) S.F. Gray,V. lathyroides L., V. pannonica Crantz, V. sativa L., V. tetrasperma(L.) Schreber, and V. villosa Roth.Aquatic, wetland or riparian species (0–3) 0Bird vetch is a weed of roadsides and disturbed areas.Total for Biological Characteristics and Dispersal 16/25Ecological Amplitude and Distribution ScoreHighly domesticated or a weed of agriculture (0–4) 4In Alaska, Vicia cracca was introduced as a forage crop inFairbanks and Palmer (Densmore et al. 2001, Klebesadel 1980).Known level of impact in natural areas (0–6) 4Bird vetch has ability to invade natural areas. The species hasbeen observed growing in open mature deciduous forest nearFairbanks (Densmore et al. 2001), and it penetrates well beyondboreal forest edges in the Susitna Valley (I. Lapina, M.L. Carlsonpers. obs.). It is a significant component of grassland in northernOntario and Quebec (Aarssen et al. 1986).Role of anthropogenic and natural disturbance in3establishment (0–5)It establishes in disturbed grassy areas and along roadsides(Nolen 2002). From these areas of disturbance bird vetch caninvade habitats with moderate amounts of light penetration(M.L. Carlson pers. obs.).Current global distribution (0–5) 5Originally native to Europe, it now occurs in North America,South Africa, temperate Asia, and New Zealand (Hultén 1968).Extent of the species U.S. range and/or occurrence of5formal state or provincial listing (0–5)Bird vetch now ranges from Alaska and British Columbia southand east across Canada to Newfoundland, south to Georgia andAlabama; a total of 36 states (USDA 2002). Vicia cracca listed asa noxious weed seed in Alaska (Group B) (Alaska AdministrativeCode).Total for Ecological Amplitude and Distribution 21/25Feasibility of ControlScoreSeed banks (0–3) 3The seeds do not germinate until the seed coat is sufficientlybroken down (by decay or abrasion) to admit water (Densmore etal. 2001). Most hard-seeded legumes have seed dormancy lasting5 years or more (M.L. Carlson pers. obs.). J. Snyder (unpubl. data)observed vetch seeds germinating without period of dormancy.Vegetative regeneration (0–3) 2There is strong vegetative growth from dormant buds ofbelowground roots (Aarssen et al. 1986).Level of effort required (0–4) 4This species is very difficult to eradicate once establishedTotal for Feasibility of Control 9/10Total score for 4 sections 73/100§B-139