Yellow mustard

Invasive yellow mustard in our foothills has displaced the coastal sage scrub plant community, including this native California buckwheat (Eriogonum fasciculatum) which blooms almost year-round and is an important food source for native insects and pollinators. 

Carpinteria’s beauty lies in the natural world that surrounds us: steep bluffs crumbling into the ocean, the sprawling, tidal world of the Carpinteria Salt Marsh and the rugged peaks of the Santa Ynez Mountains behind town. These wild spaces, which community members and local government work to preserve and protect, are vital resources for the other-than-human world pushed out by urban and suburban development.

Large areas of protected wild lands close to cities and towns are refuges for the many native plants, animals and insects upon which our own well-being depends. Protected wildlands are a source of biodiversity; a safeguard for ocean health via erosion control, and a sink for carbon storage. These are increasingly important values in the face of human-caused climate change.

Many wildlands, despite their rugged beauty, are affected by human development in the form of invasive plants. Invasive species are those introduced from other parts of the world which dominate and outcompete local flora. Scientists make a distinction between non-native, naturalized species (those that were not originally “native,” but have found a balanced niche in an ecosystem) and invasive species, which out-compete native species, often to the point of endangerment or extinction.

Plants have always found ways to move around the globe, via wind and water currents, and intentional cultivation and dispersal by earlier humans. In the Carpinteria Valley, the Chumash introduced or encouraged the growth of several plant species that were less common without human intervention. The idea of a pristine or original wilderness is complicated, since ideas of a mythical “wild” past often erase the human agency and skilled environmental management of indigenous people.  

However, the worldwide impact of invasive species is a growing problem, greatly exacerbated by the speed and ubiquity of international travel and trade, as well as by poor land management. Invasive species are contributing dramatically to the declining health of many wild systems. Invasive species, unchecked by the balance of thousands of years of co-evolution between predator and prey, insect pest and plant defense, run riot in new ecosystems.

Invasive plants can take over a landscape, making the ecosystem much less complex and healthy and leading to a chain reaction of decline. Introduced plants find ecological niches free from the predatory herbivores and insect pests or diseases keeping them in check in their native habitat. These plants displace reliable food and shelter sources for native birds, insects and animals.

The folded topography and diverse microclimates of California lead to greater specialization in ecosystems: birds that nest in only one kind of tree, insects that thrive on only one species of plant, plants that are pollinated by only one insect or animal. Thousands of years of co-evolution can be destroyed almost overnight in geological terms: invasive plants displace native plants, and their dependents are unable to recover.     

One local example is the mustard that coats our foothills in pure yellow in early spring.  Mustard has taken over large sections of our coastal mountains, turning a lively and humming community of coastal sage scrub, insects and animals into a monoculture of only one plant. Yellow mustard is also a much greater fire hazard than our native vegetation. Yellow mustard turns dry and brittle in the summer, whereas our mountain’s native plants stay green and alive (though dormant) in the summer.  Mustard is tinder, a more likely source of ignition that burns hot and fast.

Another example of the impacts of invasive plants on local communities is ice plant along our coastal bluffs. Relentless vegetative propagation covers everything in its path with such a dense mat that native seedlings do not have the room or sunlight to germinate. Ice plant increases coastal erosion: its rapid growth, dense mass and shallow root system literally pull down the bluffs. Native plants such as aromatic sages and wild sunflowers have deeper roots, preventing erosion.

There is much we can do to prioritize the health and wealth of local ecosystems.  Landscape with native plants in whatever space you’ve got, providing food and shelter for local fauna. Avoid invasive plants that may escape cultivation. Check out the California Invasive Plant Council (Cal-IPC) for a “no grow” list: cal-ipc.org/solutions/prevention/landscaping/dpp/?region=centcoast.

Andrea Adams-Morden runs monthly invasive plant removals in the Carpinteria Salt Marsh. Check CVN’s calendar: the next marsh weeding day is Aug. 3. Local restoration organization Channel Islands Restoration (CIR) hosts many volunteer opportunities for invasive species removal, including work during the winter in the Carpinteria Salt Marsh. Find out more at cirweb.org.  

Alena Steen is coordinator of the Carpinteria Garden Park, an organic community garden located at 4855 Fifth St., developed by the City’s Parks and Recreation Department.  Community members rent a plot to grow their own fresh produce. The garden is also a center for public education, with classes on organic gardening, nutrition and sustainability. For a complete schedule or more information visit carp-garden.com or follow the garden on Instagram @carp_garden.

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