Invasiveness Ranking System for Non-Native Plants of Alaska

Feasibility of ControlScoreSeed banks (0–3) 0The seeds of European bird cherry are viable for less than 1 year(Granström 1987).Vegetative regeneration (0–3) 2European bird cherry readily resprouts after removal ofaboveground growth (Heiligmann 2006). New shoots arecommonly developed, especially during the early years ofestablishment (Leather 1996).Level of effort required (0–4) 3Several control techniques can be used for control of undesirableshrubs and trees such as bird cherry. Cutting, frilling, or girdlingcan be used for control of bird cherry. Combination of mechanicaltreatments with herbicide applications is generally more effective(Heiligmann 2006).Total for Feasibility of Control 5/10Total score for 4 sections 74/100§Ranunculus repens L. andRanunculus acris L.Ranking SummaryEcoregion known or expected to occur inSouth CoastalInterior BorealArctic AlpineYesYesYesPotential Max. ScoreEcological Impact 40 16Biological Characteristics and Dispersal 23 13Amplitude and Distribution 25 15Feasibility of Control 10 9Relative Maximum 54Climatic ComparisonCollected inAlaska regions?CLIMEXsimilarity?South Coastal Yes –Interior Boreal Yes –Arctic Alpine Yes –Creeping buttercup has been reported from all ecogeographicregion in Alaska (Hultén 1968). Tall buttercup has been collectedin the south coastal and interior boreal ecogeographic regions inAlaska (Hultén 1968, University of Alaska Museum 2003)The CLIMEX computer matching program indicates the climaticsimilarity between Nome and areas where Ranunculus acris isdocumented is moderately high. The species range includes Rørosand Dombås, Norway (Lid and Lid 1994), which have a 76% and63% climatic match with Nome, and 55% and 52% climatic matchwith Fairbanks, respectively. Thus establishment of Ranunculusacris in interior boreal and arctic alpine ecogeographic regionsmay be possible.Ecological ImpactScoreImpact on Ecosystem Processes (0–10) 3Both species of non-native buttercup readily occupy open areasand may hinder colonization by native species (Harper 1957,Lovett-Doust et al. 1990).Impact on Natural Community Structure (0–10) 3Buttercup establishment may increase the density of thevegetation. In Lovett-Doust’s study (1981) the density of creepingbuttercup ramets was 264 per m² and 112 per m² in woodland andgrassland, respectively. Sarukhan and Harper (1973) reportedup to 385 ramets per m² in intensly grazed grassland. In Alaskacreeping buttercup has been observed at covers near 100%(T. Heutte pers. obs.).Impact on Natural Community Composition (0–10) 3Buttercup reduces the number of individual native plants ininvaded communities (J. Heys pers. obs., C. McKee pers. obs.).common names: creeping buttercup andtall buttercupImpact on Higher Trophic Levels (0–10) 7The protoanemonin released in the sap of creeping and tallbuttercups is poisonous and can cause death to grazing animalsif consumed. Geese and other birds readily eat leaves and seedsof buttercup (Lovett-Doust et al. 1990). The flowers are visitedby honeybees, butterflies, moths, bugs, and beetles for pollenor nectar (Steinbach and Gottsberger 1994). Buttercups hostmicroorganisms and viruses, insects, and nematodes (Harper1957, Lovett-Doust et al. 1990, Royer and Dickinson 1999).Apparently Ranunculus acris and R. uncinatus hybridize in Alaska(Welsh 1974). However, no hybrids have been recorded in Britainand Canada and experimental crosses between Ranunculusspecies have been unsuccessful (Harper 1957, Lovett-Doust et al.1990).Total for Ecological Impact 16/30Biological Characteristics and Dispersal ScoreMode of Reproduction (0–3) 2Creeping and tall buttercup are capable of producing up to 80 and240 seeds per plant, respectively (Sarukhan 1974). Production ofdaughter ramets is the major mechanism of population increasefor creeping buttercup (Lovett-Doust et al. 1990).Long-distance dispersal (0–3) 2Although most seeds are dropped near the parent plant, someseeds are dispersed farther by wind, or in the dung of birds, farmanimals, and small rodents (Harper 1957, Lovett-Doust et al.1990).Spread by humans (0–3) 3The seeds can be dispersed by attachment to clothes and tires.Creeping buttercup may have been introduced as an ornamentalplant into North America (Lovett-Doust et al. 1990). Gardenvarieties have been grown and escaped from gardens in Alaska(J. Riley pers. obs.).Allelopathic (0–2)UThere is an unconfirmed hypothesis that buttercups have toxicroot secretions detrimental to neighboring plants (Lovett-Doustet al. 1990).Competitive Ability (0–3) 1Creeping buttercup is capable of withstanding competition fromtall-growing grasses (Harper 1957).Thicket-forming/Smothering growth form (0–2) 0Buttercups do not form dense thickets nor are they characterizedby climbing growth habit.B-108