Our office is conducting an investigation entitled, Designing Herbicide-Based Management Strategies for Use in Endangered Butterfly Habitats.  The Endangered Species Program and the Environmental Contaminants Program within our office are working collaboratively with the Baskett Slough National Wildlife Refuge and Washington State University in Vancouver on this study.

The primary objective is to determine if the risks to endangered butterflies from direct spraying of herbicides in their habitat outweighs the usefulness of herbicides for controlling the non-native invasive plants that compete with the butterfly’s host plants.  A combination of field, laboratory and modeling approaches will be used. 

If risk from herbicides is judged acceptable, the results of this study will help guide managers in herbicide selection and application timing geared to minimize effects to at-risk butterfly species.  This information is needed to help recover endangered butterflies.