Those who toured Antioch Dunes National Wildlife Refuge in the spring are now able to add one more species to their species list.  The vision of cows munching on grass may have startled some wildlife watchers who are familiar with the inland dune ecosystem known for its endemic rare plants and animals.

Once a large complex of riverine sand dunes, the site is now limited to 55 acres due to urban development and sand mining activities up to the establishment of the refuge in 1980.  Most of the original habitat and sand substrate are gone and the site, rather than being reminiscent of dunes, is more comparable to a flat or a pit.  Without active, moving sand dunes, invasive non-native plant species have the upper hand throughout the refuge.  These invasive non-native plants out-compete two endemic endangered plants, the Contra Costa Wallflower (Erysimum capitatum var. angustatum) and the Antioch Dunes Evening Primrose (Oenothera deltoiodes spp. Howellii). It also out-competes the naked stem buckwheat ((Eriogonum nudum var.auriculatum) which is the host plant for the endangered Lange’s Metalmark Butterfly (Apodemia mormo langei). 

Measures to eliminate the non-native plants over the past several years included hand pulling and chemical and mechanical controls.  While these practices have worked, the invasion of non-natives has out-paced control efforts.  A faster and more sustainable system of controlling invasive species was needed.  Without aggressive management actions, the extinction of the Lange’s metalmark butterfly is imminent.

Partnering with the Sonoma County Agricultural Extension Office and a local rancher, the grazing experiment is exactly that, an experiment on only ten acres of the refuge.   If successful, it will remove 30% of the non-native vegetative cover and provide an environment where buckwheat, primrose and wallflower will begin to establish or recruit naturally.  Grazing is not expected to be a “cure-all” for controlling invasive plants, but rather another tool to complement other management efforts.

Funding for this project was provided through the Central Valley Project Improvement Act, Habitat Restoration Program.

For information contact Refuge Manager, Christy Smith, 707.769.4200.