Gold Bluffs Beach Dune Restoration

Redwood National and State Parks staff, as well as CCC volunteers have been successful in removing invasive European Beach Grass from hundreds of acres of important dune habitats. This invasive species is meeting its match. Michelle Forys. California State Park Environmental Scientist

NPS: G Litten

European beachgrass (Ammophila arenaria) is known to alter dune morphology, sand movement and native plant community composition, decrease invertebrate abundance and diversity, and negatively impact native pollinators. Beachgrass has steadily displaced the native plant communities at Gold Bluffs Beach, contributing to the loss and degradation of the dune habitats found there. The dunes provide habitat for multiple sensitive native dune plants such as pink sand verbena (Abronia umbellata spp. breviflora), dune pea (Lathyrus japonicas), and American glehnia (Glehnia littoralis subsp. Leiocarpa). These species often occur in the Abronia latifolia-Ambrosia chamissonis (dune mat) Alliance and Elymus mollis ssp. mollis (sea lyme grass) Alliance, vegetation types considered rare and worthy of special consideration by the California Department of Fish and Wildlife. In addition, there is potential habitat for two rare plant species; beach layia (Layia carnosa) (federally endangered) and dark-eyed gilia (Gilia millefoliata).

Beachgrass also threatens the Pacific Coast population of western snowy plovers (Charadrius nivosus nivosus), a federally listed shorebird. Loss and modification of habitat resulting from beachgrass invasion, urban development, recreation activities, and predation exacerbated by human disturbance were found to be largely responsible for the decline of this species. Removal of beachgrass from the project area is anticipated to result in the enhancement of breeding habitat for snowy plovers.

Between 2004 and 2008, 32 acres of beachgrass within a 105 acre project area located between Ossagon Trailhead and Carruthers Cover were treated successfully using heavy equipment (28 acres) and hand removal (4 acres) techniques. Guided by the principals of adaptive management, this project area was encompassed in the larger North Gold Bluffs Beach Coastal Dune Restoration Plan in 2012. The plan employs Integrated Weed Management to restore 550 acres of coastal dune habitats. Implementation of this new project began in fall 2012, with the hand removal of beachgrass around sensitive plants and habitats. The majority of the nearshore habitat under plan was treated using heavy equipment in fall 2013 (100 acres) and fall 2015 (100 acres). Since 2004 approximately 280 acres of beachgrass have been treated using heavy equipment (228 acres) and manual removal (52 acres) techniques.

The project area will be retreated 3 times a year until the beachgrass infestations are at a maintenance level (one retreatment a year).
Although the majority of the project area was covered in beachgrass patches of native dune vegetation persisted, and beachgrass in those areas were treated by hand to preserve the native vegetation. Seeds from the native vegetation have begun to disperse into the mechanically treated areas. To enhance the native plant recruitment additional seeding with native dune plants was conducted in 2013 and 2015. Species that were collected on site and used for seeding the treatment area included yellow sand verbena (Abronia latifolia), pink sand verbena, and American glehnia. In addition, several dozen beach strawberry (Fragaria chiloensis) and beach evening primrose (Camissoniopsis cheiranthifolia) were transplanted into the treatment area.

After only a few years the dunes system in the treatment area has begun to rebound. Prior to initial treatment there was one occurrence of pink sand verbena consisting of 5 individual plants scattered over a 3.7-acre area. In 2016, there were 165 occurrences of pink sand verbena consisting of approximately 2,160 individuals spread throughout the project area. Since implementation began in 2012 snowy plovers have consistently been observed within and adjacent to the treatment area at Gold Bluffs Beach. Park managers plan to continue restoration efforts as funding becomes available.

Before and After Beachgrass Removal at Gold Bluffs Beach

Left image
Before removal of beachgrass

Right image
After removal of beachgrass