Invasiveness Ranking System for Non-Native Plants of Alaska

Extent of the species U.S. range and/or occurrence of5formal state or provincial listing (0–5)It occurs in nearly all states of the United States (USDA 2002).It is listed as noxious in 15 American states and in 4 Canadianprovinces (Invaders Database System 2003, USDA 2002).Total for Ecological Amplitude and Distribution 21/25Feasibility of ControlScoreSeed banks (0–3) 3Seeds remain viable in the soil up to 5 years (Lym and Zollinger1992). After 8 years about 30% of seeds may be viable (Mauer etal. 1987).Vegetative regeneration (0–3) 2Lateral root-sprouting is possible for Centaurea biebersteinii(Carpinelli 2003, M. Shephard pers. com.).Level of effort required (0–4) 4Long-term control requires a combination of managementtechniques. Several years of monitoring are required to exhaustthe seed bank. Most knapweed control has been conducted inagricultural settings and little information is available for the useof herbicides in native communities (Lym and Zollinger 1992,Rice et al. 1997). A number of biological control agents have beenmoderately successful in Montana and other western states (Storyet al. 1989, Story et al. 1991).Total for Feasibility of Control 9/10Total score for 4 sections 86/100§Cerastium fontanum common names: common mouse-ear chickweed,ssp. vulgare (Hartman) Greuter & Burdetbig chickweedCerastium glomeratum Thuill.,sticky chickweedRanking SummaryEcoregion known or expected to occur inSouth CoastalInterior BorealArctic AlpineYesYesYesPotential Max. ScoreEcological Impact 40 6Biological Characteristics and Dispersal 25 8Amplitude and Distribution 19 15Feasibility of Control 10 5Relative Maximum 36Climatic ComparisonCollected inAlaska regions?CLIMEXsimilarity?South Coastal Yes –Interior Boreal Yes YesArctic Alpine No YesCerastium fontanum ssp. vulgare has been documented ininterior boreal and south coastal ecogeographic regions ofAlaska (AKEPIC 2005, Hultén 1968, UAM 2004, Welsh 1974).Cerastium glomeratum is known from many disjunct localitiesin south coastal, interior boreal and arctic alpine ecogeographicregions in Alaska and Yukon (Hultén 1968, UAM 2004, Welsh1974). Cerastium fontanum ssp. vulgare has a cosmopolitandistribution with introduction into a variety of climatic zonesincluding arctic and subarctic (Hultén 1968). Using the CLIMEXmatching program, the climatic similarity between Nome andother areas where the species is documented is fairly high. Therange of the species includes Chirka-Kem’, Arkhangel’sk, andZlatoust, Russia (Gubanov et al. 2003, Hultén 1968), which havea 77%, 76%, and 71% of climatic match with Nome respectively.This suggests that establishment of common mouse-earchickweed in Alaska arctic and alpine ecoregions may be possible.Ecological ImpactScoreImpact on Ecosystem Processes (0–10) 1Common mouse-ear chickweed and sticky chickweed do notappear to occur in high densities in natural areas in Alaska.The impact of these species on ecosystem processes is nearlynegligible (J. Conn pers. obs., M. Carlson pers. obs.).Impact on Natural Community Structure (0–10) 3Common mouse-ear chickweed and sticky chickweed likely alterthe density of the layer of vegetation (Ohio perennial and biennialweed guide 2006).Impact on Natural Community Composition (0–10) 1On disturbed ground common mouse-ear chickweed and stickychickweed can form a mat that excludes other plants (Ohioperennial and biennial weed guide 2006). However, these specieshave not been observed in undisturbed plant communitiesin Alaska (M. Carslon pers. obs.) and its impact on nativecommunity composition is not documented.Impact on Higher Trophic Levels (0–10) 1Flowers of common mouse-ear chickweed are self-pollinated andrarely visited by insects (Mulligan 1972). Both species are host forsome nematodes (Townshend and Davidson 1962).Total for Ecological Impact 6/40Biological Characteristics and Dispersal ScoreMode of Reproduction (0–3) 3Common mouse-ear chickweed and sticky chickweed reproduceby seeds and stems rooting at the nodes (Ohio perennial andbiennial weed guide 2006).Long-distance dispersal (0–3) 2Seabirds probably have some role in transport of seeds. Viableseeds of Cerastium species were found in pellets of sea gulls(Gillham 1956).Spread by humans (0–3) 2Common mouse-ear chickweed and sticky chickweed are weedsof gardens and lawns. Seeds can be transported with horticulturalstock (Hodkinson and Thompson 1997).Allelopathic (0–2) 0Common mouse-ear chickweed and sticky chickweed are notknown to be allelopathic.B-18