Invasiveness Ranking System for Non-Native Plants of Alaska

Role of anthropogenic and natural disturbance in1establishment (0–5)Soil disturbances by animals, vehicles, and natural erosionprovide suitable open areas for germination and establishment ofthis species (Densmore et al. 2000, Sagar and Harper 1964). Thisplant usually does not persist without redisturbance. In Alaskait is found primarily on sites disturbed within the last 10 years(Densmore et al. 2001, AKEPIC 2004).Current global distribution (0–5) 5This taxon is generally believed to originate in Europe, but it isnow cosmopolitan in distribution. Range of distribution includesarctic regions. (Dempster 1993, Hultén 1968, Sagar and Harper1964, Whitson et al. 2000).Extent of the species U.S. range and/or occurrence of5formal state or provincial listing (0–5)Common plantain has been recorded from all states of theUnited States. It is listed as an invasive weed in Connecticut,Washington, Manitoba, and Quebec (USDA 2002). Plantagospecies are restricted noxious weeds in Alaska (AlaskaAdministrative Code 1987).Total for Ecological Amplitude and Distribution 16/25Feasibility of ControlScoreSeed banks (0–3) 3Seeds buried in the soil remained viable for 3.5 years in Michigan(Duvel 1904). Chippendale and Milton’s (1934) results suggestthat viability is maintained for 50–60 years.Vegetative regeneration (0–3) 2Common plantain has the ability to resprout from the crown,roots, or root fragments (Densmore et al. 2001, Rutledge andMcLendon 1996).Level of effort required (0–4) 2This species does not persist without repeated anthropogenicdisturbance. However, multiple weeding treatments may benecessary to eliminate plants germinating from buried seeds androot fragments. It is easily controlled by herbicides (Densmore etal. 2001, Rutledge and McLendon 1996).Total for Feasibility of Control 7/10Total score for 4 sections 44/100§Poa annua L.Ranking SummaryEcoregion known or expected to occur inSouth CoastalInterior BorealArctic AlpineYesYesYesPotential Max. ScoreEcological Impact 40 8Biological Characteristics and Dispersal 25 13Amplitude and Distribution 25 18Feasibility of Control 10 7Relative Maximum 46Climatic ComparisonCollected inAlaska regions?CLIMEXsimilarity?South Coastal Yes –Interior Boreal Yes –Arctic Alpine Yes –Poa annua has been collected from all ecogiographic regions inAlaska (Hultén 1968).Ecological ImpactScoreImpact on Ecosystem Processes (0–10) 1Annual bluegrass is a pioneer species that is often dominant andmay hinder colonization by native species by reducing availablenutrients in the soil surface (Bergelson 1990).Impact on Natural Community Structure (0–10) 3Annual bluegrass may form dense mats and dominate, reducingthe vigor of other plants (Hutchinson and Seymour 1982). Fieldexperiments suggested that native seed germination and seedlingsurvival is reduced in the presence of annual bluegrass litterImpact on Natural Community Composition (0–10) 1Litter of annual bluegrass may inhibit other species germinationreducing the number of individuals in the community (Bergelson1990).common names: annual bluegrassImpact on Higher Trophic Levels (0–10) 3The seeds of annual bluegrass are eaten by various species ofbird. The plants are probably eaten by deer. A wide range ofinvertebrates feed on annual bluegrass. It forms hybrids withP. glauca and P. pratensis in Britain. (Hutchinson and Seymour1982). Annual bluegrass is an alternate host for number of viruses(Royer and Dickinson 1999).Total for Ecological Impact 8/40Biological Characteristics and Dispersal ScoreMode of Reproduction (0–3) 3Annual bluegrass reproduces primarily by seed, which isproduced rapidly in the season. Seed production rate may exceed20,000 in a season under ideal conditions (Hutchinson andSeymour 1982, Rutledge and McLendon 1996).Long-distance dispersal (0–3) 2The seeds have no special adaptation for long-distance dispersal,but are likely dispersed by rain, wind, and birds. Seeds remainviable after passing through the digestive tracts of some animalssuch as cows, horses, and deer (Hutchinson and Seymour 1982,Rutledge and McLendon 1996).Spread by humans (0–3) 3Seeds can be carried in mud on boots and vehicles. It iscommonly transported as an impurity of lawn grass seed(Hodkinson and Thompson 1997, Hutchinson and Seymour1982, Rutledge and McLendon 1996, Whitson et al. 2000).Allelopathic (0–2) 0Annual bluegrass is not allelophathic (USDA 2002).B-95