California Sea Grant College Program

In this project, the Delta Science Fellow compiled several years of airborne hyperspectral imaging data to produce detailed maps of the distribution of the invasive perennial pepperweed (Lepidium latifolium) at sites in the Sacramento San Francisco Bay-Delta.

From the maps, inferences were made about the habitats that attract this noxious invasive plant, facilitate its spread and are vulnerable to future infestation. The Solano Land Trust, a nonprofit that purchases land for preservation, is using the maps to

more strategically and cost-effectively contain existing infestations and prevent colonization of presently weed-free places.

Perennial pepperweed is a long-lived herbaceous member of the mustard family, native to southeastern Europe and Asia and now common in the western United States. It forms large, dense stands with extensive root systems, displacing native vegetation, reducing native habitat for wildlife. Established populations are difficult to control and easily spread along entire stream corridors and irrigation structures. Floods often wash away roots growing along stream banks, spreading infestations progressively downstream.