The Yolo County Resource Conservation District is working with the Xerces Society and landowners to increase breeding and foraging habitat for western monarch butterflies across the county.
In an announcement made Wednesday, Amy Williams, project manager for the district, reported this fall district staff will work with landowners, land managers, and volunteers to plant 6,400 monarch habitat plants provided by the Xerces Society and grown by Hedgerow Farms to six sites countywide.
“The majority of the plants being installed are narrow-leaf milkweed, and showy milkweed, larval host plants for western monarch caterpillars,” Williams stated. “Native wildflowers will be planted alongside the milkweed to provide nectar sources for monarch butterflies and many other pollinators.”
She noted the wildflowers were chosen for their bloom times with the goal of providing a food source throughout the monarch breeding and migration season.
“Together, the milkweed and nectar plants should provide food and habitat that will help the western monarch butterfly population to recover,” she added.
As monarch butterflies migrate, they must have the right plants in bloom along their migration route to fuel their flight. Producers — especially those along California’s coast and in the Central Valley and Sierra foothills — can play an important role in helping the species.
Western monarch populations have decreased by 99% since the 1980s, in part due to habitat loss in breeding grounds and overwintering sites. In 2018, the western monarch population declined to the lowest level ever observed — less than 30,000 individuals were counted, down from 192,000 counted in 2017, an 86% decrease in a single year.
Restoring breeding ground and nectar sources has been seen as a possible solution to rejuvenate the monarch butterfly population.
In February, the U.S. Department of Agriculture asked farmers to implement a number of conservation practices to help the monarch butterfly population.
“With the monarch butterfly’s western population in peril, we’re encouraging California producers to make simple tweaks on their farms that can go a long way for this iconic species,” said Carlos Suarez, state conservationist with USDA’s Natural Resources Conservation Service in California. “NRCS offers more than three dozen conservation practices that enable producers to help monarchs and other pollinators as well as benefit their agricultural operations.”
Through a variety of conservation practices, NRCS helps producers to plant healthy stands of milkweed and high-value nectar plants and protect these stands from exposure to pesticides.
Planting native milkweeds is important to rebuild the western monarch population, but scientists at the Xerces Society recommend that milkweed not be planted within five miles of overwintering sites near the coast. It did not typically occur there and may prevent returning monarchs from going into their winter clusters.
NRCS also recommends California producers to establish plants that bloom in the fall, as monarchs head to coastal overwintering sites, and in the late winter and very early spring, as the winter clusters of monarchs break up. These fall-blooming species include goldenrod and asters, and late-winter species include coyote brush, manzanitas, and native California lilac and other Ceanothus species.
