Pollinators are critically important for food production and healthy ecosystems. Pollinators (bees, flies, butterflies and other invertebrates) have declined to various degrees across North America, prompting concern. The Washington State Department of Transportation (WSDOT) has implemented a multi-faceted approach to protect and enhance pollinator habitat along roadsides under its jurisdiction: 1) development of three geographic information system (GIS) models to identify and rank roadsides and urban gateway areas with high-value habitat for monarchs and other pollinators; 2) preservation or enhancement of pollinator habitat in WSDOT’s right of way through the application of ecological design principals to support pollinator habitat in high-value areas; 3) implementation of best management practices (BMPs) for roadside maintenance, 4) completion of a study of seed mixes and seeding methods to identify best methods for enhancing roadside pollinator habitat, and 5) development of a study to identify effective milkweed relocation methodologies. WSDOT landscape architects will identify and preserve native habitat along roadsides where feasible, and revegetate using native plant species that includes shrubs and pollinator-friendly seed mixes providing sequentially available nectar throughout the growing season. Maintenance activities will follow BMPs that prescriptively manage mowing and herbicide applications in high-value pollinator habitat. In 2022, WSDOT finished a multi-year study to evaluate the effects of different seed mixes and site preparation methods on pollinator abundance and diversity. WSDOT is currently developing a study to investigate BMPs for milkweed relocation along roadsides in eastern Washington. The data will be used to implement monarch host plant management and habitat enhancement efforts. Based on habitat modeling, landscape design, maintenance BMPs, and ongoing research, WSDOT can implement statewide restoration, creation, or enhancement of pollinator habitat in the right of way in all facets of operations, maintenance and construction.
seed mix treatment