The land that runs alongside much of the Sonoma County coastline, though not directly impacted by vanishing kelp or sea creatures, is also experiencing the impact of outside intervention.
Coastal prairies, a type of grassland, are common along the coast where plants are able to receive moisture from fog. According to a resource put out by the Sonoma Marin Coastal Grasslands Working Group (part of Sonoma State University’s Center for Environmental Equity), California has lost 90% of its native coastal prairie land.
As non-native species begin to take over land that was once full of native, coast-specific plants, local organizations are trying to combat the spread of invasive species and allow for the recuperation of the land and the species.
At Salt Point State Park and Manchester State Park in Mendocino County, the California State Parks are working to cultivate the local coastal prairie to encourage the return of Behren’s silverspot butterfly.
“We’re comparing mowing and grazing to reduce our invasive grassland and create more flowering plants,” said Terra Fuller, senior specialist environmental scientist for the Sonoma-Mendocino District of the California State Parks system.
According to the U.S. Fish and Wildlife Service, the butterfly has been listed as endangered since 1997.
A final recovery plan for the species was released in 2016, and outlines the species being spotted as far south as Salt Point.
By periodically mowing and introducing grazing to the area throughout 2018-20, the state parks system is hoping to recreate the floral habitat that’s ideal for Behren’s silverspot butterfly.
“The elimination of burning, the elk population and the invasion of non-native grasses has resulted in a dense monoculture of invasive grasses,” reads a flyer put out by California State Parks.
As such, the invasive species taking over Salt Point State Park and Manchester State Park are using resources necessary for the growth of the early blue violet, the only host plant for the butterfly.
Once grazing and other forms of invasive species management reduces the level of invasive grasses in the area, propagated early blue violets will be planted in an effort to help increase the amount of Behren’s silverspot butterflies in the area.
At the Bodega Bay Marine Reserve, restoration efforts on the coast are focused on bringing back species of plants native to the area, and taking out the non-native species that have taken over.
“There’s been a real push to acknowledge the coastal prairie that we have, classify and understand that, and focus on the coastal prairie that we have and rehabilitate it and restore it,” said Suzanne Olyarnik, reserve director at the Bodega Bay Marine Reserve.
For the past 10 years, the reserve has primarily focused its rehabilitation efforts on dealing with velvet grass (Holcus lanatus), an invasive species of grass that easily reproduces, forming mats in the land that once housed an abundance of native plant life.
“Velvet grass really changes the community,” Olyarnik said. “It’s a really wicked enemy. It reproduces both sexually and asexually, it puts out an astronomical amount of seeds from each plant, but it also grows under the ground. What it tends to do is make these big mats — in doing so it really outcompetes a lot of the native species around it.”
The level to which velvet grass takes over the surrounding area has led to reduced species diversity in the area, changing land that was once full of a variety of plant life into land that’s primarily taken over by one kind.
To try and fight against the onslaught of this invasive species, the folks at the Bodega Bay Marine Reserve have worked to pull, mow and herbicide their way through the swaths of velvet grass.
In areas that are less dense, volunteers go out and help pull the plant; areas that have dense coverage of the plant are subjected to monocot-specific herbicides meant to knock the density down; and other areas are mowed over before the plant flowers and has a chance to let out seeds.
After mowing the plant over repeated years, Olyarnik said that the lack of growth will cause the plant to die off over time.
Different kinds of eradication work aside, “there isn’t a silver bullet for Hulcus,” Olyarnik said.
Every year, the reserve monitors the land and keeps track of where the velvet grass is located. Doing so allows them to keep track of what plants they need to remove, as well as enables them to make sure no large groupings of the grass are forming.
“There’s a lot of management that has to be done every year,” she said. “Every year we do our satellite searches, so new plants can’t get a foothold, and then we continue to work to knock back places where it’s gotten out of hand.”
After years of work — and more to go — the native species are coming back.
“What we expected to have to do was go in and replant a lot of the natives, but what we found is that because we have such a good seed bank, we didn’t even have to do the replanting,” Olyarnik said. “Once the Holcus was knocked back, the natives were able to fill in.”
Since the Bodega Bay Marine Reserve has been protected as a reserve for 50 years and has had limited levels of outside impact, the land has been able to build up a sizeable native seed bank.