Alsea Estuary-Alsea River – State Wildlife Action Plan

Geographic boundaries of the COAs were updated for the 2026 State Wildlife Action Plan and the associated COA profiles are intended to provide additional information. Content of each COA profile is being refined and will be updated to reflect current conditions when feasible. Please help us by submitting information on Local Conservation Actions, Plans, or Potential Partners to: OCS.revision@odfw.oregon.gov.

The Alsea Estuary-Alsea River COA (55 mi²) extends from the Alsea Estuary upstream along the Alsea River toward Trenholm Saddle. It includes the associated riparian upland habitat surrounding the river. This COA is adjacent to the Beaver Creek and Yachats River Area COAs.

Recommended Conservation Actions

Limit the placement of docks and boathouses in the estuary.
Promote creation of upland meadow habitats on USFS lands.
Protect and restore estuarine shorelines from hardening and dynamic revetment modifications (rip rap, rock, etc.).
Protect harbor seal pupping areas from disturbance during pupping season.
Protect steep, landslide prone areas from timber harvest activities.
Protect the estuary from commercial shellfish development.
Remove remaining dikes and tide gated areas to recover lost salt marsh habitats.

Local Conservation Actions and Plans

Potential Partners

Special Features

General

The Alsea Estuary is large and shallow and provides overwintering habitat for migrating waterfowl, rearing habitat for coastal salmonids, harbor seal pupping islands, great blue heron rookeries, and eagle and osprey nesting sites.

This COA has had extensive salt marsh habitat restoration.

Protected Areas

Alsea Bay Historic Interpretive Center
Bayview Oxbow Preserve
Bunker Creek
Drift Creek Wilderness
Governor Patterson Memorial State Recreation Site
Siuslaw National Forest
Starr Creek Preserve
W.B. Nelson State Recreation Site

Previous COA Association

Size Change from 2016 boundaries: +2.5 mi² (5% increase)

Specialized Local Habitats

Aquatic vegetation beds
Bays
Forest openings
Intertidal mudflats
Off-channel habitat
Sand spit

Ecoregions

Coast Range

Oregon's Coast Range, known for its dramatic scenery, is extremely diverse, with habitats ranging from open sandy dunes to lush forests and from tidepools to headwater streams. It follows the coastline and extends east through coastal forest to the border of the Willamette Valley and Klamath Mountains ecoregions

Nearshore

The Nearshore ecoregion includes a variety of habitats ranging from submerged high-relief rocky reefs to broad expanses of intertidal mudflats in estuaries and hosts a vast array of fish, invertebrates, marine mammals, birds, plants, and micro-organisms. This ecoregion encompasses the area from the outer boundary of Oregon's Territorial Sea to the supra-tidal zone, and up into the estuaries.

Key Habitats

Coastal Dunes

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.

Estuaries

Estuaries are broadly defined as partially enclosed coastal bodies of tidally influenced water with one or more inputs of freshwater, and with a free or intermittent connection to the open sea. Estuaries typically occur at locations where freshwater from rivers, streams, or creeks meets saltwater from the nearshore ocean, creating a tidal basin that experiences frequent …

Grasslands

Grasslands include a variety of upland grass-dominated habitats, such as upland prairies, coastal bluffs, and montane grasslands.

Late Successional Mixed Conifer Forests

Late successional mixed conifer forests provide a multi-layered tree canopy, including large-diameter trees, shade-tolerant tree species in the understory, and a high volume of dead wood, such as snags and logs.

Natural Lakes

Natural lakes are relatively large bodies of freshwater surrounded by land that were formed through geological processes, such as glacial scouring, tectonic movements, volcanic activity and river meander cutoffs. In Oregon, natural lakes are defined as standing water bodies larger than 20 acres, including some seasonal lakes. Depth is not a reference for characterization of …

Example of Oak Woodlands, which is a Strategy Habitat within the State Wildlife Action Plan

Oak Habitats

There are several oak habitat types in Oregon, where oaks comprise most of the canopy. These can include oak woodlands, oak forest, oak chaparral, and riparian oak. Oak savanna is covered in the Grasslands Key Habitat. Oaks may also co-dominate a canopy in oak/fir, oak pine, and oak hardwood habitats.

Flowing Water and Riparian Habitats

Flowing Water and Riparian Habitats include all naturally occurring flowing freshwater streams and rivers throughout Oregon as well as the adjacent riparian habitat.

Ducks on a wetland in Ladd Marsh Wildlife Area, Oregon

Wetlands

Wetlands are habitats that are inundated or saturated by surface water or ground water at a frequency and duration sufficient to support vegetation typically adapted for life in sodden soil conditions. While dominated by periods of inundation, the natural ecological cycle may also include dry intervals. Permanently wet habitats include backwater sloughs, oxbow lakes, peatlands, …

Nearshore Key Habitats

Nearshore Habitats encompass the coastal and marine habitats in the area from the 3 nautical mile outer limit of Oregon’s territorial sea, where water depths average 66 m (216 ft) and range from 17 m to 194 m (56 to 308 ft), to the supratidal areas of the shoreline affected by wave spray and overwash …