09 Apr Salmon Habitat Restoration Projects Enhance Habitat for Pollinators
This was originally submitted for publication in Forest and River News, Spring 2022 edition.
The Salmon Protection and Watershed Network (SPAWN) focuses on protecting and improving habitat for central coast coho salmon and the forests and watersheds they need to survive in the Lagunitas creek watershed of Marin County, CA. We have restored more than 15 acres of riparian habitat over the past 5 years and continue to implement new habitat restoration projects each year using plants grown in our Native Plant Nursery. This nursery was initially very small, located in the back yard of a volunteer, with the purpose of growing plants to be used for restoration. Although we’ve grown and even have full-time staff now, the nursery is still powered by volunteers. Our nursery, currently located on National Park Service land, contains about 8,000 plants. We currently grow about 100 different species of native plants with seeds and propagules sourced from the Lagunitas Creek watershed.
Along with plants, insects are at the base of the food web. We are becoming increasingly aware of the decline of insects, which greatly effects the food supply for native salmonids. Young coho and steelhead, as well as other fish and birds, rely on insects as their source of food. Insect populations have dropped dramatically over the past hundred years. Insect populations are in decline due to a variety of factors including habitat loss, pesticide use, climate change, and disease. This crisis is known as the “insect apocalypse”.
According to The Xerces Society, although fewer than 1 percent of described invertebrate species have been assessed for threats by the International Union for Conservation of Nature, approximately 40 percent of all those that have been assessed are considered threatened. The decline of insect biomass over the past decades is visible. The observation that over the past hundred years fewer insects have been found on car windshields has been described as “the windshield phenomenon”.
Many pollinator species are experiencing a rapid population decline, including the iconic Western monarch butterfly. In the annual Thanksgiving count of 2020, which is organized by The Xerces Society, less than 2,000 monarchs were counted in the overwintering grounds along the coast of California. There were nearly 4.5 million monarchs in California just 30 years ago. Many factors have contributed to the decline of monarchs, including use of pesticides and herbicides, increased wildfires, loss of habitat and habitat fragmentation, and loss of milkweed (Asclepias species), which is necessary to monarchs for reproduction.
In an effort to protect the Western monarch and other pollinators, SPAWN has started adding native nectar plants, especially those that bloom in the fall and spring when monarchs are migrating to and from the coast, to our riparian restoration sites. Some of the fall and spring-blooming nectar-rich plants which support monarchs that we commonly include at our riparian sites are California lilac, pink-flowering currant, canyon gooseberry, California aster, and grass-leaf goldenrod. Additionally, monarchs are known to frequently use riparian channels as flyways along their migratory route to the coast.
At our newest project site, known as Roy’s Riffles located in San Geronimo, CA, we have planted hundreds of plugs of perennial nectar plants. Riparian restoration sites provide ideal conditions to enhance habitat for pollinators and other insect species, especially those located in open, sunny wild areas, since the land is already going through the process of restoration. The Xerces Foundation offers habitat kits for areas in California that have been created specifically for riparian zones. SPAWN has used the Xerces habitat kits in our restoration projects.
Milkweed in commonly associated with monarchs since they are the exclusive host plant to their caterpillars. A common misconception is that milkweed can be planted anywhere and will benefit monarchs. That is not the case. Milkweed should not be planted in coastal areas. When planted too close to the coast, within about 5 miles, milkweed can be disruptive to the migratory cycle of monarch butterflies and cause adults to breed instead of going to overwintering grounds in the fall or to lay eggs too early while they are overwintering on the coast. However, it is appropriate to add milkweed to sites that are located further inland where adults migrate in the spring and summer to lay eggs. Milkweed grows best in sunny areas which contain groundwater, such as a seep area or a swale.
SPAWN also is planting to help native bees. Buckeye trees are an important source of spring nectar to native bees, and although they are mildly toxic to European honeybees, the honeybees will avoid buckeye flowers if other options are available. Toyon provides a good source of nectar for bees, butterflies, and other pollinators in late spring. Some of the nectar-rich shrubs and perennials we include at our project sites which attract and benefit native bees include willows, creek dogwood, coffeeberry, coyote mint, wooly sunflower, marsh gumplant, and yarrow. In addition to planting nectar plants, we improve habitat for insects by providing the ground covers that they need for protection from sun, wind, and predators by sowing native grass seed and planting rushes and sedges.
In addition to supporting insects through restoration we have planted demonstration pollinator gardens around the SPAWN Nursery and at local schools and public buildings. These act as “waystations” to help pollinators migrate to-and-from the coast, and to educate the public about how to garden for the benefit of pollinators. The nectar-rich gardens, which all contain locally native plants, also attract ladybugs and other beneficial insects. A monarch nectar plant demonstration garden at SPAWN Nursery contains fall and spring-blooming nectar plants such as California goldenrod, Western vervain, California aster, and Pacific gumplant. The garden also includes groundcovers such as purple needlegrass, miniature lupine and tomcat clover.
In fall 2019 SPAWN partnered with another organization called Home Ground Habitats to create a program called Bringing Nature to School. This program creates habitat gardens in schoolyards; the objectives are to provide students with opportunities for hands-on learning in nature and to improve habitat for wildlife. Over the past two years the program has built six new monarch waystations at local schools. Each garden is adapted to the fit the local conditions of each school to maximize benefits to wildlife. The Bolinas-Stinson school, located on the coast, has created a 2,300 square foot mounded pollinator garden which does not contain milkweed and instead focuses on providing late fall, winter, and early spring-blooming nectar plants. Another school garden, located at the Lagunitas school and San Geronimo Community Center, was created in combination with a salmon habitat restoration project. As part of the project scope, an old storage shed and sandbox was removed from a former playground area on the banks of Larsen Creek. These were removed to reduce sand from escaping and pouring into the creek. The site was transformed into a habitat oasis for pollinators, birds, and other wildlife and can also be used as a teaching space and a place that community members and students can relax and enjoy nature. Another program partner, Glenwood Elementary in San Rafael, has transformed an unused strip of land in front of the school into a monarch waystation which is so rich in species diversity that it contains the host plants for more than 20 species of butterflies.
Several schools have also partnered with SPAWN to grow narrowleaf milkweed (Asclepias fascicularis) at their schools. The students sow the seeds and care for the seedlings and then donate the plants to SPAWN Nursery at the end of the school year. SPAWN has organized annual narrowleaf milkweed give-away and tropical milkweed trade-out programs to provide native milkweed to gardeners who want to add the appropriate milkweed species to their garden. The milkweed plants propagated by students at partner schools, along with information about how to care for narrow-leaf milkweed and how to garden for monarchs in Marin County, are given away to any interested gardener. The milkweed is available to individuals, schools, and businesses. More than 200 milkweed plants were given away in fall 2021. Many new waystations were created as a result of this initiative.
The SPAWN Nursery has informational handouts available to help people plant natives that will benefit monarchs, native bees, and other insects. This information can be useful to property owners, land managers, gardeners, landscapers, etc. These handouts are available on the SPAWN Nursery webpage.
The Western monarch population declined to less than 2,000 individual butterflies in 2020 and within one year increased to 247,237 butterflies, as counted during the 2021 Thanksgiving count. This incredible population rebound shows that it is possible for the Western monarch to recover and that taking direct action to help the monarch recovery is critical. Moreover, by placing an emphasis on building habitat for insects in restoration projects we are helping to create healthy ecosystems from the base level up and we are working to avert the “insect apocalypse”.
SPAWN’s work aims to link the connections between instream and riparian habitat, and placing an emphasis on enhancing habitat for insects is an example of this connection. Our work to save endangered coho salmon and monarch butterflies reflects the need to plan restoration efforts around a wholistic, multi-species approach. Working to restore habitat for both coho and Western monarchs has even more overlap than we thought, and our aim is to make these connections better known among the environmental restoration community through projects that demonstrate success.