Invasiveness Ranking System for Non-Native Plants of Alaska

Biological Characteristics and Dispersal ScoreMode of Reproduction (0–3) 1Yellow salsify reproduces by seed only. Plants may produce asmany as 500 seeds (Royer and Dickinson 1999).Long-distance dispersal (0–3) 3The seeds are wind dispersed with a pappus of hairs that promotelong-distance dispersal (Royer and Dickinson 1999).Spread by humans (0–3) 2Yellow salsify is a potential seed contaminant (USDA, ARS2004).Allelopathic (0–2) 0It is not listed as allelophathic (USDA 2002).Competitive Ability (0–3) 1Yellow salsify is not an aggressive weed (Rutledge and McLendon1996); however, it likely competes moderately with native speciesfor moisture and nutrient.Thicket-forming/Smothering growth form (0–2) 0Although yellow salsify can grow to 3 feet tall (Royer andDickinson 1999, Whitson et al. 2000), it does not form densestands or thickets (I. Lapina pers. obs.).Germination requirements (0–3) 3Seedlings of yellow salsify emerge and survive in different typesof vegetative cover, including thick stands (Gross and Werner1982).Other invasive species in the genus (0–3) 1A number of Tragopogon species has been introduced to NorthAmerica. Tragopogon porrifolius and T. pratensis are consideredto be weedy (Stebbins 1993). T. pratensis hybridizes with otherspecies creating aggressive weedy hybrids T. ×crantzii Dichlt.[dubius × pratensis] and T. ×neohybridus Farw. [porrifolius ×pratensis] (USDA, NRCS 2006, Owenby 1950).Aquatic, wetland or riparian species (0–3) 0Yellow salsify is a common weed of cultivated crops, roadsides,and waste areas (Royer and Dickinson 1999, Rutledge andMcLendon 1996) and not of riparian areas or wetlands.Total for Biological Characteristics and Dispersal 11/25Ecological Amplitude and Distribution ScoreHighly domesticated or a weed of agriculture (0–4) 2Yellow salsify is a weed of cultivated crop (Rutledge andMcLendon 1999).Known level of impact in natural areas (0–6) 3Yellow salsify has been found in areas disturbed in the lastdecade. It does not appear to have a perceivable impact onnatural plant communities (Rutledge and McLendon 1996). Itcan establish in relatively high population densities in intact tomoderately grazed prairies in Oregon (M.L. Carlson pers. obs.).Role of anthropogenic and natural disturbance in3establishment (0–5)Yellow salsify generally occurs on disturbed sites (Rutledge andMcLendon 1996). It readily established in grazed prairies. Steepslopes and slides are also susceptible to invasion (M.L. Carlsonpers. obs.).Current global distribution (0–5) 3Native range of yellow saslify includes mid and southern Europeand temperate Asia. It is now established over much of temperateNorth America (USDA, ARS 2004).Extent of the species U.S. range and/or occurrence of5formal state or provincial listing (0–5)Yellow salsify occurs in nearly all states of the United States(USDA 2002). This species is considered an invasive weed inTennessee, Manitoba, and Ontario (Royer and Dickinson 1999).Total for Ecological Amplitude and Distribution 16/25Feasibility of ControlScoreSeed banks (0–3) 0Seed longevity for yellow salsify is very short. Generally seedsgerminate the next year after dispersal (Chepil 1946).Vegetative regeneration (0–3) 0Yellow salsify does not resprout after removal of abovegroundgrowth (USDA 2002).Level of effort required (0–4) 3Multiple years of management (hand pulling) of infestation alongTurnagain Arm have been unsuccessful (M. Shephard pers. obs.,J. Snyder pers. obs.).Total for Feasibility of Control 3/10Total score for 4 sections 50/100§B-131