Coastal Dunes – State Wildlife Action Plan

Oregon Coastal Dunes Strategy Habitat Photo Credit: Rebecca Kennison, Creative Commons

Occurring along the Oregon coastline, coastal dunes provide habitat for species that prefer open, sandy habitats with a high degree of disturbance from winds and tides.

Ecoregions

Coastal dunes are a Key Habitat in the Coast Range ecoregion.

Characteristics

The Coastal Dunes Key Habitat includes beaches, foredunes, sand spits, deflation plains, and active dunes to stabilizing back dunes. The vegetation varies from sparse to forested, as influenced by sand scour, deposition, movement, and erosion. Species composition is also influenced by salt spray, storm tidal surges, wind abrasion, and substrate stability. Beaches and sandspits are directly impacted by tidal action and are unvegetated. Foredunes generally have unstable sand and sparse to moderate vegetative cover, including native beachgrass, seashore bluegrass, gray beach peavine, largehead sedge, beach morning glory, yellow sand verbena, and silver beachweed. In dunes with greater sand stability, red fescue, seashore lupine, beach pea, coastal strawberry, dune tansy, beach knotweed, and pearly everlasting are dominant. Over time, with plant succession, dunes convert to coastal prairies and grasslands, then to shrublands dominated by salal and evergreen huckleberry, and eventually to forests dominated by shore pine, Sitka spruce, western hemlock, and Douglas-fir.

HABITAT CHANGE TRENDS ANALYSIS

Loss of Coastal Dunes

To investigate loss of coastal dune habitat, the Institute of Natural Resources (INR) compared the total area and spatial overlap of vegetation classes in two baseline maps (1855-1910 and 2016). The analysis showed loss of coastal dune habitat over time. By 2016, the total area of coastal dunes had declined by 24% when compared to historical data. There was also evidence of significant shifts in where open dune habitat is located, with some previously open dunes becoming vegetated and stabilized, and new open sand dunes established where dunes were previously stabilized.

Conservation Overview

Coastal dune communities have been altered dramatically through the introduction and spread of non-native European beachgrasses, which outcompete native vegetation and stabilize foredunes. The stabilized foredunes block movement of sand inland and artificially accelerate plant succession toward shrubland and forest. Dunes artificially stabilized by non-native beachgrasses have contributed to commercial and residential development of sandy habitats that were once naturally active, shifting shoreline ecosystems. In Oregon, almost all coastal dunes have been altered from their natural state since 1850.

Species that live in coastal dune habitats generally prefer open, sandy environments with a high degree of disturbance from winds and tides. Species of Greatest Conservation Need associated with coastal dunes include the Western Snowy Plover, Pacific marten, pink sand verbena, Wolf’s evening primrose, silvery phacelia, and seaside gilia.

Photo Credit: USFWS. Western Snowy Plovers nest on the beach, making their eggs and young susceptible to disturbance from recreational activities.

Limiting Factors and Recommended Approaches

Limiting Factor: European Beachgrass and other Invasive Plants

European beachgrass stabilizes dunes, resulting in changes in vegetative communities and loss of open sandy habitats that are vital to native species. Stabilized dunes are vulnerable to other invasive non-native species, such as hybrid beachgrasses, Scotch broom, and gorse, which displace native plants and animals and accelerate succession. Encroachment by shore pine and other woody species is also an issue.

Recommended Approach

Use mechanical and chemical treatment to control European beachgrass in priority areas, such as Western Snowy Plover nesting areas and near pink sand verbena populations. Build on existing restoration efforts to control beachgrass. Control key invasive non-native plants using site-appropriate tools, such as mechanical (e.g., mowing, girdling, hand-pulling), chemical, and biological control (for gorse) treatments.

Limiting Factor: Development

Stabilized dunes are targeted for development for residential housing, which leads to habitat loss and increased direct/indirect impacts to wildlife through disturbance.

Recommended Approach

Use voluntary cooperative approaches, such as financial incentives, Candidate Conservation Agreements with Assurances, and conservations easements with private landowners to maintain dune habitats. Work with agency partners to support and implement Statewide Land Use Goal 18, “Beaches and Dunes”.

Limiting Factor: Recreational Impacts

In some areas, recreational use can disturb wildlife habitat (e.g., Western Snowy Plover nesting areas). Off-leash dogs may also disturb habitat and chase or harass wildlife. Off-highway vehicles can also impact vegetation and disturb wildlife.

Recommended Approach

Work with land managers to direct recreational use away from sensitive areas. Close areas to access during sensitive or vulnerable periods. Provide recreational users with information on coastal dune conservation issues and low impact uses.

Resources for more information

Oregon Coastal Management Program

Oregon Dunes Cooperative Weed Management Area: Management Plan

An analysis of coastal sand dune management in Oregon (United States) from the 19^th to the 21^st century.

Oregon Dunes Restoration Collaborative

REFERENCES

Brunner, R. and E. Gaines. 2025. Oregon Vegetation Change 1851-2023. Trends analysis conducted for Oregon Department of Fish and Wildlife. Institute for Natural Resources, Portland State University, Portland, OR, USA.

Weidemann, A.M., L.J. Dennis, and F.H. Smith. 1999. Plants of Oregon Coastal Dunes. Oregon State University Press, 120 p.

OPRD‘s Ocean Shores Management Plan: https://www.oregon.gov/oprd/PRP/Documents/PRP_PLA_OS_FinalOceanShoresMP052305.pdf

Snowy Plover Habitat Conservation Plan: https://www.oregon.gov/oprd/PCB/Documents/WSP-HCP_08182010-web.pdf