By Martha Berthelsen
Children’s drawings decorate our office wall. The drawings feature bright orange birds, trees with spring green leaves and burnt sienna trunks, and turquoise fish surrounded by squiggly blue lines for a creek. These urban students were given the opportunity to sit quietly by a restored creek and sketch what they saw, heard, and imagined. In this brief excursion away from classrooms and asphalt playgrounds, they clearly appreciated the quiet beauty of the creek.
Restoring small patches of nature in our cities has multiple benefits, for people and plants as well as for the birds and the bees. Volunteers in our restoration projects can learn about the incredible diversity of native plants in the Bay Area, and the myriad ways these plants provide food and shelter for animal species. Visitors to the sites can study ethnobotany and the ecological history of California, or just enjoy the view.
Meanwhile the chickadees and warblers go about their business of cleaning insects off the willow leaves, and the tiny native bees collect pollen and nectar from elderberries to provision their nests. The pollinators help make berries for migrating birds, which carry the seeds to an open space for a new seedling to grow. Plants and birds and innumerable insects are all linked in a complex set of interdependent relationships that have evolved together for over 10,000 years. Underneath them all is the soil and the water underground or flowing in the creek.
How do we go about protecting this intricate system? We lay a foundation of local native plants, then let nature do the rest. Choosing plants for a restoration site is part science, part art. We rely on published studies as well as our own observations of what grows well in our watersheds. A useful framework is the concept of plant communities, groups of species found together because they have similar environmental requirements.
Riparian (creekside) plants need moisture in the soil most of the year, so are installed close to the creek. Sedges and rushes do well adjacent to water, where their fibrous roots anchor the bank and their grass-like tops flex and bend in high winter flows. Buckeyes and big leaf maples lean over to shade and cool the water. Forest or woodland understory plants such as pink-flowering current and wild strawberry benefit from shade, which lowers water stress in our dry summers.
The top of the banks and upland slopes can be dry and sunny, and a good place for coastal scrub community species. Sticky monkey flower with bright yellow blooms and gray-leaved California sagebrush thrive here. Grasslands, once the most common community in much of the bay area, flourish in clay soils. Numerous wildflowers, from annual clarkias to perennial fall blooming California asters grow in between clumps of long-lived bunch grasses.
Each species is specially adapted to a given set of conditions defined by water, sun and soil type. Together, the diversity of plants and animals form a mosaic of life. Humans have the ability to protect or destroy these important natural systems. For the sake of the plants, animals, and our own enjoyment, now is the time to support watershed restoration efforts.
Clarkia photo by Gudrun Kleist.