CogKnoSys

Knowledge you can walk. Read the idea below, then step up to the general, across to peers or down to the specific.

Physical

Lower Columbia Ecosystems and Wildlife

Lower Columbia wildlife and habitats: Columbia River Salmon Runs and the national wildlife refuges along the river.

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The idea

In the Northwest, salmon are keystone species. That means they affect other wildlife far more than their total weight would suggest. Salmon hatch in rivers or lakes and grow up in the ocean. Then they swim back upriver to spawn, usually in the very river where they were born. Most species migrate in the fall, from September through November. The runs feed bears, bald eagles and other hunters. All Pacific salmon die after spawning, and their bodies carry nutrients from the ocean to rivers, wetlands and forests.

Ridgefield National Wildlife Refuge borders the Columbia River west of Ridgefield, Washington. It is overseen by the United States Fish and Wildlife Service and is split in two by Lake River. It protects more than 5,200 acres of marsh, grassland and woods. Birds live there all year or stop to rest while migrating. Steigerwald Lake National Wildlife Refuge is a wetland on the Columbia River, 10 miles east of Vancouver, Washington. By 2019 it covered about 1,200 acres of wetlands, fields and woodlands.

Check yourself

Question 1 of 2

Which of these refuges opened a Community Nature Center for visitors in May 2026?

Pick one. The first pick counts.

Composition

what it's made of

  • Columbia River Salmon Runs — Yearly migrations of salmon from the ocean back up rivers to spawn.
  • Ridgefield National Wildlife Refuge — More than 5,200 acres of marsh, grassland and woodland beside the Columbia River.
  • Steigerwald Lake National Wildlife Refuge — A floodplain wetland on the Columbia River east of Vancouver, Washington.
  • Migrating Birds — Birds that use the refuges as a year-round home or a migration stop.
  • Salmon Predators — Bald eagles and other animals that feed on returning salmon.

Connection

how it relates

Under Lower Columbia Region

In place

  1. Columbia Riverstrength 90 of 100

    Both wildlife refuges sit on the Columbia River, and salmon runs travel up it from the ocean.

Related

  1. Habitatsstrength 70 of 100

    The refuges protect habitats such as marshes, grasslands, woodlands and floodplain wetlands.

  2. Food Chainsstrength 60 of 100

    Salmon runs are a major feeding event for predators, linking ocean food chains to river and forest ones.

  3. Biodiversitystrength 50 of 100

    As keystone species, salmon support many other kinds of wildlife in the places they reach.

Change

how and why it evolves

Past
From the 1960s until 2021, a levee cut the Steigerwald refuge off from the Columbia River. In 2021 crews removed more than 2 miles of it, and when the refuge reopened in May 2022, 965 acres of floodplain were joined to the river again.
Now
In May 2026, the Ridgefield refuge opened a Community Nature Center at its Carty Unit, built mainly as a place to teach visitors.
Next
Now that the river can again flood the Steigerwald floodplain each season, salmon and lamprey will likely keep finding new places there to feed and shelter.

Knowledge you can walk. Read the idea, then step up, across or down.

Lower Columbia Ecosystems and Wildlife

Lower Columbia wildlife and habitats: Columbia River Salmon Runs and the national wildlife refuges along the river.

Learn, discuss, create, buy or invest

The idea

In the Northwest, salmon are keystone species. That means they affect other wildlife far more than their total weight would suggest. Salmon hatch in rivers or lakes and grow up in the ocean. Then they swim back upriver to spawn, usually in the very river where they were born. Most species migrate in the fall, from September through November. The runs feed bears, bald eagles and other hunters. All Pacific salmon die after spawning, and their bodies carry nutrients from the ocean to rivers, wetlands and forests.

Ridgefield National Wildlife Refuge borders the Columbia River west of Ridgefield, Washington. It is overseen by the United States Fish and Wildlife Service and is split in two by Lake River. It protects more than 5,200 acres of marsh, grassland and woods. Birds live there all year or stop to rest while migrating. Steigerwald Lake National Wildlife Refuge is a wetland on the Columbia River, 10 miles east of Vancouver, Washington. By 2019 it covered about 1,200 acres of wetlands, fields and woodlands.

Check yourself

2 quick questions, instant feedback.