Butterfly Restoration Project
Since 2009 we have been working at the north end of Swan Lake to remove noxious weeds and restore maritime prairie habitat to bring back the endangered Taylor’s Checkerspot Butterfly and, we hope, other critically threatened butterfly species. We are planting micro-habitat plots, experimenting with various larval and nectaring host plants favored by the butterfly, and monitoring to see whether our plantings can survive the foraging of Eastern Cottontail Rabbits.
The Taylor’s Checkerspot once was widespread in the San Juan Islands, southern Vancouver Island and the surrounding islands of British Columbia, as well as on coastal and inland grasslands, open prairies and gravelly outwash areas of Puget Sound, Washington and Oregon. With a wingspan of less than 2-1/2 inches, it is an orange, black and white butterfly that flies in the spring in the Puget Sound lowlands.
The native grasslands it favors are particularly vulnerable to agricultural use, urban development and the encroachment of trees and invasive plants. Such grasslands once were estimated at 250,000 acres in Western Washington. Today only a few acres remain. Butterflies are susceptible to pesticides, recreation and farm grazing. According to one recent study, only 14 sites remain in the Pacific Northwest where Checkerspot populations exceed 50 individuals. Because of the Checkerspot’s sensitivity to changes in its habitat, it is considered a keystone species, an environmental indicator for the health of entire ecosystems.
As of summer 2010, it appears the rabbits will not eat Plectritis congesta, commonly called Seablush. This is a pretty, pink annual that grows with ease in our watershed. We are encouraging our neighbors to plant Seablush in their gardens to help the Checkerspot Butterfly recover. We typically order seeds in the fall for the following gardening season. Seeds are not commercially available because the plants are rare. Please contact us if you wish to wish to order these seeds for yourself.
In the winter of 2012 four additional micro-habitat plots were burned and planted with Camas, Sea blush and Indian paintbrush in addition to numerous native prairie species for a total of five intentionally planted micro-habitat plots.
We annually mow the microhabitat plots plus the border of the restoration area to prevent encroachment into the maritime prairie by the native Rosa nutkana, a wild-rose shrub that grows as a hedge protecting the site from the road at eastern border of the acreage. And we seasonally work at diminishing the number of Himalayan black berry and poison hemlock plants by mowing, snipping seed heads (which are hauled offsite) and manually digging up plants. Following any digging, the areas are replanted with native seed mixes that include a high percentage of native grass seed from the site.
The results of our efforts as of the summer of 2013 have been surprising and delightful. Towards maritime prairie restoration we have discovered native red fescue, California oat grass and Pacific sanicle in addition to Plantago lanceolota, a novel larval host plant for the Taylor’s checkerspot (“TC”) and native trailing blackberry, a novel nectaring host plant for the TC. We have also found a small patch of native strawberry plants that are also used as a nectaring host plant for the TC.
Surveys in 2013 yielded no evidence of the TC but we are hopeful that our efforts will be rewarded in coming years. The site is rich with ecological diversity and although we have not yet found evidence of the TC returning to the site, we have found abundant wildlife including the following butterfly species: Spring Azure, Woodland Skipper, Cabbage White and Mylitta Crescent.