An examination of the soils supporting Hackelia venusta, Washington State's most endangered species

Abstract

<italic>Hackelia venusta </italic> (Showy stickseed) is an endemic, endangered species restricted to a small forested area in the eastern footslopes of the Cascade Mountains in Washington State. The purpose of this study was to characterize the soils supporting H. venusta according to their chemical and physical properties. The soils are shallow, well-drained and coarse-textured with low organic matter content. Percent base saturation is high although cation exchange capacity is low. Total and extractable N are low but similar to forest soils of other locations with similar site characteristics. Bray extractable P is high and may be somewhat attributed in part to small amounts of volcanic ash in the soil. However, given the history of fire in the study area it is most likely attributed to increased mineralization of P as a result of burning. A single, excavated <italic>H. venusta </italic>specimen revealed a shallow root system that demonstrated obvious strain against continuous erosion of surface materials. DNA extraction of several root and rhizosphere soil samples indicated that arbuscular mycorrhizal fungi may be associated with the species.