Invasiveness Ranking System for Non-Native Plants of Alaska

Feasibility of ControlScoreSeed banks (0–3) 3Ninety-nine percent of viable seeds will germinate in the first2-years. The rest of the seeds may be viable in the soil for up to8 years. However, viability deceases by about 13% each year(Butterfield et al. 1996, Whitson et al. 2000). Selleck et al. (1962)reported seeds remain viable no longer than 5 years.Vegetative regeneration (0–3) 2Root buds give rise to new shoots after removal of abovegroundparts. Root fragments buried 9 feet deep can produce new plants(Royer and Dickinson 1999). An experiment showed that tillingincreased the density of leafy spurge from 134 shoots/m² inuntilled area to 316 shoots/m² (Selleck et al. 1962).Level of effort required (0–4) 4Leafy spurge is extremely difficult to control, and the bestapproach is the early detection and elimination of new infestation.Mechanical, chemical, cultural, and biological control methodshave all been used on leafy spurge with varying levels of success.Most control methods have a detrimental effect on other plantspecies, and they all constitute a disturbance that will promotethe establishment of leafy spurge or other exotic species (Mastersand Kappler 2002, Biesboer 1996, Lym 1998, Selleck et al. 1962).Treated sites require monitoring for 10 years after treatment.Total for Feasibility of Control 9/10Total score for 4 sections 84/100§Fallopia convolvulus (Linnaeus) Á. Löve(Polygonum convolvulus L.)Ranking SummaryEcoregion known or expected to occur inSouth CoastalInterior BorealArctic AlpineYesYesYesPotential Max. ScoreEcological Impact 40 12Biological Characteristics and Dispersal 25 16Amplitude and Distribution 25 17Feasibility of Control 10 5Relative Maximum 50Climatic ComparisonCollected inAlaska regions?CLIMEXsimilarity?South Coastal Yes –Interior Boreal Yes –Arctic Alpine Yes –Polygonum convolvulus has been documented in all ecogeographicregions of Alaska (Hultén 1968, Welsh 1974, UAM 2004,AKEPIC 2005).Ecological ImpactScoreImpact on Ecosystem Processes (0–10) 3Black bindweed quickly covers bare soil (Hume et al. 1983,Rutledge and McLendon 1996). It may prevent native speciesfrom establishing.Impact on Natural Community Structure (0–10) 3Black bindweed is able to create a dense canopy, coveringherbaceous plants (Friesen and Shebeski 1960, Royer andDickinson 1999). However, dense stands of black bindweed havenot been observed in native communities in Alaska (J. Conn pers.obs.).Impact on Natural Community Composition (0–10) 3Black bindweed is a strong competitor (Fabricius and Nalewaja1968, Friesen and Shebeski 1960, Pavlychenko and Harrington1934, Welbank 1963) and it likely reduces the number ofindividuals in the native species community.common names: black bindweedImpact on Higher Trophic Levels (0–10) 3The seeds and leaves of black bindweed are an important foods forgranivorous birds (Wilson et al. 1999). It also is an alternate hostfor a number of fungi, viruses, and nematode species (Cooperand Harrison 1973, Royer and Dickinson 1999, Townshend andDavidson 1962)Total for Ecological Impact 12/40Biological Characteristics and Dispersal ScoreMode of Reproduction (0–3) 3Black bindweed reproduces by seed only. A single plant is capableof producing up to 11,900 to even 30,000 seeds (Stevens 1932,Forsberg and Best 1964).Long-distance dispersal (0–3) 1The seeds have no adaptation for long-distance dispersal, butapparently they can be transported by water (Hume et al. 1983,Rutledge and McLendon 1996).Spread by humans (0–3) 2The seeds of black bindweed are commonly dispersed by farmmachinery. This plant is also a frequent cereal crop contaminant(Gooch 1963, Rutledge and McLendon 1996, J. Conn pers. obs.).Black bindweed seeds remain viable after digestion by ruminants,therefore, it may be transported by animals (Blackshaw and Rode1991).Allelopathic (0–2) 0Black bindweed is not known to be allelopathic.Competitive Ability (0–3) 2Black bindweed is able to compete with cultivated crops and otherweeds for moisture, nutrients, and light (Friesen and Shebeski1960, Welbank 1963, Fabricius and Nalewaja 1968, Royer andDickinson 1999). In experimental studies black bindweed appearsto be a stronger competitor than Chenopodium album, Polygonumaviculare, P. persicaria, Stellaria media, and Capsella bursa-pastoris(Pavlychenko and Harrington 1934, Welbank 1963).Thicket-forming/Smothering growth form (0–2) 2Black bindweed climbs and smothers other plants and can formdense thickets (Rutledge and McLendon 1996). A density of56 to 215 plants per m² has been observed in number of studies(Friesen and Shebeski 1960)B-38