I Hogle, JH Viers, JF Quinn, Perennial Pepperweed Infestation on the Cosumnes River Experimental Floodplain A Report to the California Bay-Delta Authority

Riparian floodplains present a unique challenge for restoration management, in that these are, by definition, dynamic, constantly changing ecosystems. As restoration projects are initiated and progress through time, both native and invasive species can become established. During the initial invasion and stages of establishment and colonization, management may be effective in controlling the impact of non-native invasive species in restoration areas. However, it is critical to have effective information on the location and nature of weed populations to prioritize and sustain management activities. We use a combination of field monitoring and spatial modeling to determine rates of Lepidium latifolium spread on a riparian floodplain restoration site and to determine what, if any, environmental and physical factors may limit expansion of Lepidium infestations at this site. Our research combines tracking of population dynamics with spatial analyses to assess differences in Lepidium invasion as a function of distance to potential propagule source, degree of shading, and degree of inundation resulting from microtopographic floodplain gradients.