Author(s): Dayne Filer , Jon Weese , Michelle Eide

Presentation: poster

The Snake River Birds of Prey National Conservation Area (NCA) has one of the highest densities of nesting raptors in North America. In recent years NCA vegetation has been changing rapidly due to a succession of invasive plant species. Bur buttercup (Ranunculus testiculata), an allelopathic plant from Central Asia, has established itself in NCA and appears to be replacing another earlier invasive species, cheatgrass (Bromus tectorum). We wished to determine if its patchy distribution in NCA could be explained by differences in soil characteristics between areas with and without bur buttercup. We collected 90 soil samples from three sites in NCA and analyzed them for texture, nitrates, electrical conductivity, pH, compaction, and cover using standard methods. Electrical conductivity and nitrate concentrations were significantly (p<0.001) higher in samples from areas with bur buttercup than areas without. Furthermore, soils were significantly (p<0.001) less compacted and had significantly (p=0.013) higher clay content in areas with bur buttercup. Other soil texture classes and pH were only marginally different. As suspected, soil characteristics vary significantly with bur buttercup distribution. Further studies will ideally elucidate if soil differences cause or result from bur buttercup distribution to better understand and possibly prevent its future spread.

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