June is national pollinator month and a great time to recognize the importance of pollinators. NRCS has numerous programs and conservation practices to benefit habitat for many pollinators, including honeybees, native bees, butterflies and other pollinators. To best support the creation and management of butterfly habitat, it’s important to understand the special needs of butterflies. Plant Materials Centers (PMCs) in western states are actively studying butterfly habitat development practices and producing useful tools for NRCS field offices regarding butterfly conservation.
Instead of having bee mouth parts, adult butterflies feed on nectar using a long straw-like tube called a proboscis. For this reason, any pollinator habitat created with butterflies in mind, needs to include a suite of flowers known to produce nectar and not just pollen. Western PMCs have developed a number of resources to help guide field offices in butterfly habitat design such as Idaho Plant Materials Technical Note 71: Monarch Butterfly Habitat: Development and Maintenance and Idaho Plant Materials Technical Note 73: Creation and Management of Utah Butterfly Habitat.
Numerous butterfly species may soon warrant listing as a threatened or endangered species not only because plants for adults are less available, but also because host plant populations for larvae (caterpillars) are diminishing. NRCS PMCs are directing their expertise to better understanding the production, establishment, and promotion of those plants critical to all stages in the life cycles of western butterflies.
Monarch butterflies, for example, are perhaps the most iconic insect in North America; however, this species faces severe challenges. Experts predict that Western monarch numbers have been steadily and dramatically decreasing since the 1980’s. One of the factors linked to monarch declines is the reduction of available milkweed (Asclepias spp.) populations. Adult monarchs will only lay eggs on milkweed plants, which comprise the sole food source for the developing larva.
PMCs in California, Oregon, Montana and Idaho have been studying milkweed to determine best practices for habitat restoration and management. The Aberdeen PMC in Idaho is investigating the propagation of milkweed via root or rhizome cuttings. They have found that root cuttings of showy milkweed (A. speciosa) as small as 1/8” diameter can produce new plants. This technique may provide an effective method to establish milkweed in native habitats as well as, home flower gardens. Aberdeen PMC staff are conducting field burning treatments as part of a study investigating milkweed management for monarch butterfly habitat. Likewise, the Corvallis, Oregon and Lockeford, California PMCs are studying practices to establish and manage milkweed species in seed mixtures to produce optimum monarch habitat. In Montana, the Bridger PMC worked collaboratively with the Teller Wildlife Refuge, Pheasants Forever, NRCS Hamilton Field Office, and the Montana State University Ag Experimental Station to establish a milkweed and pollinator planting to evaluate different milkweed planting methods.
A further group of western butterflies that are threatened due to host plant population losses are the silverspots or fritillaries. These beautiful checkered butterflies rely on violets (Viola spp.) to produce their offspring. The Corvallis and Aberdeen PMCs are studying methods of violet seed and plant production to aid conservation efforts in critical habitats. In Corvallis, they published findings on practical solutions for seed production of early blue violet (V. adunca), while scientists at Aberdeen have begun investigating propagation and seed production of northern bog violet (V. nephrophylla).
In addition to these specific activities, PMCs have developed several publications outlining management practices and species appropriate for butterfly habitat in the many ecoregions of the western states. For more information, visit the website of the PMC in your area.