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Pollinators: Probably varied rather than specific. In Washington, observed insect visitors <br /> include several bee species, and a butterfly Coenonympha ampelos. No pollinator <br /> observations have been reported from Oregon. <br /> Seed /fruit dispersal and establishment mechanisms: Seeds are adapted to wind dispersal <br /> due to the bristly pappus. Dispersal by animals such birds and rodents may also occur. <br /> In greenhouse competition experiments, seedlings fared poorly under competition with other <br /> plants, and seedling recruitment is probably rare nature (Clampitt 1987). <br /> Potential habitat modifications: Though possibly tolerant of some grazing, persistent and <br /> high levels of grazing by domestic livestock may be detrimental and lead to extirpation of A. <br /> curtus. Even if A. curtus survives grazing, grazing may promote an increase in non - native <br /> grasses and forbs, which may have competitive advantages over native species such as A. <br /> curtus. Many A. curtus sites have been subject to invasion by woody vegetation. Prescribed <br /> fire may be beneficial in preventing invasion of woody species such as Douglas fir, Oregon <br /> white oak, Oregon ash, snowberry (Symphoricarpos albus) and Scot's broom (Cytisus <br /> scoparius) . Aster curtus appears to survive low intensity grassland fires, but the most <br /> appropriate fire return interval is not known. Since this species flowers and sets seed during <br /> the primary fire season in its prairie habitats, frequent fires (such as annually) might be <br /> detrimental over the long term, but the effects of fire on plant vigor and abundance has not <br /> been addressed with research or monitoring. <br /> Herbivory, seed predation and disease: A. curtus appears to be palatable to cattle, sheep <br /> and horses. Clampitt (1987) reported that seed predators had infested one or two heads on <br /> ramets that he analyzed for his pollinator exclusion experiment. Aster curtus (along with <br /> other species of Aster) may be a food plant for the field crescent butterfly (Phyciodes <br /> campestris), a butterfly that is rare in the Willamette Valley, though more common <br /> elsewhere, which is apparently limited to native prairie remnants. <br /> Impacts of exotic plants: Sod - forming grass species such as Agrostis tenuis appear to inhibit <br /> seedling growth (Clampitt 1987). Other non - native herbaceous species, such as <br /> Anthoxanthum odoratum, Festuca arundinacea, Chrysanthemum leucanthemum, Daucus <br /> carota, Hypochaeris radicata, and Plantago lanceolata are probably equally problematic. <br /> Cytisus scoparius produces heavy shade which may lead to a decline in abundance and vigor <br /> of A. curtus and its leaf litter may promote colonization of weedy species which can out - <br /> compete A. curtus. <br /> 2) Scientific Name: Erigeron decumbens Nutt. var. decumbens <br /> Common Name: Willamette daisy <br /> Family: Asteraceae (Compositae) <br /> 5 <br />