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Open water habitats are characterized by the absence of emergent vegetation.

Aquatic plants which are rooted underwater, but grow above the surface of the water, are called emergent vegetation. This kind of vegetation is not present in open water habitats. Submergent vegetation, which is aquatic vegetation which grows underwater, may be present, especially along the shorelines.

Carty Lake, located in the Carty Unit, fills each winter when the Columbia River rises and backs water into the lake. Although the river levels drop in the summer months causing Carty Lake to evaporate, the lake seldom dries up completely before the next winter recharge.

Open Water Animals

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Freshwater wetland habitats are areas that have waterlogged soils, support plants adapted to wet soil, and are occasionally submerged by water.

Historically, the areas along the shores of the Columbia River flooded during periods of heavy rainfall and during May and June when mountain snows melted. This flooding created a vast mosaic of seasonal wetlands along the entire course of the river.

Most of the natural wetland areas along the Columbia River have been destroyed by dams and development. The wetlands on the refuge are a small remnant of the once vast wetland system.

Freshwater Wetland Plants and Animals

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Field habitats all lack shrubs and trees.

Although refuge fields may be composed of different types of vegetation, they all lack shrubs and trees. Some are composed of natural plants and can be found along the edges of agricultural fields or in small open patches of habitat not farmed or grazed.

Most refuge fields, however, are in agricultural production and provide winter food for wildlife. Wildlife such as coyotes, hawks, and rabbits make use of the edges of the fields for hunting or cover.

Field Plants and Animals

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Riparian woodland habitats are woodlands that grow on or near the banks of watercourses.

Riparian woodlands are forests associated with flowing bodies of water, such as streams and rivers. Riparian forests are located along the Columbia River shoreline and along Gee Creek.

Dense stands of Pacific willow grow along the sand and gravel bars of the islands and ponds that flood each year. Oregon ash and black cottonwood woodlands were established years ago when the Columbia River floodwaters inundated the area.

Riparian woodlands are especially valuable to wood ducks, hooded mergansers, great horned owls, tree and violet-green swallows, and raccoons, which nest and raise young in natural cavities.

Riparian Woodland Plants and Animals

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Upland woodland habitats are habitats containing trees, shrubs, and a ground layer of vegetation.

Two types of upland woodlands are found on the Carty Unit. The Oregon white oak and Douglas-fir woodlands represent unique examples of communities not commonly found along the lower Columbia River.

The Oregon white oak habitat occupies basalt knolls and ridges above the flood zone. The oaks are found in closed-canopy stands interspersed with open grassland, wildflowers, serviceberry, snowberry, and ocean spray.

The Oaks to Wetlands Trail passes through several Douglas-fir communities. These stands are found in the highest areas on the refuge, because, like the oaks, they do not tolerate wet soil conditions. Common understory plants include salal, vine maple, ocean spray, and Indian plum, with a ground layer of Oregon grape and sword and bracken ferns.

Upland Woodland Plants and Animals

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To provide the best wildlife habitat, both natural and agricultural habitat management philosophies and techniques are followed.

For management purposes, the refuge is divided up into five units:

• Carty
• Roth
• Bachelor Island
• River "S"
• Ridgeport Dairy

The management objective of the Carty, Roth, and Ridgeport Dairy Units is preservation of the natural Columbia River floodplain. The River "S" and Bachelor Island units are managed to maximize habitat for waterfowl and other wetland wildlife.

Wetland Management

The wetlands on the Carty and Roth Units are not actively managed, but are exposed to the natural spring flooding of the Columbia River to preserve the natural floodplain. Much of the Bachelor Island and River "S" Units are protected from flooding by dikes around their perimeters.

Some of the wetlands are managed to provide natural vegetation. The seeds from natural aquatic plants provide valuable winter food to wildlife.

Reed canarygrass has invaded many of the wetlands in the refuge. The canarygrass is mowed during late summer and early fall to provide the short, green vegetation preferred by Canada geese and wigeon ducks. Canarygrass research is being conducted on the refuge.

Field Management

Most refuge fields are in agricultural production and provide winter food for wildlife. These pastures are grazed by cattle owned by refuge "cooperators," and are clipped in the fall to provide short, succulent green browse for Canada geese and wigeon ducks.

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Try these classroom and field trip activities to learn more about refuge habitats and habitat management.

Habitat Matching Game: Can you match the bird to its refuge habitat? (requires Flash)

Habitat Crisscross: Print out this crisscross puzzle, then answer the clues. Click on the glossary button at the top of this page if you need help.

Thinking it Over: Print out this matrix to help you describe your favorite place from your trip to the refuge. You'll use all of your senses!

Habitat Bingo: Play this bingo game on your trip through the refuge.

Run for the Border: Make observations about the differences in plant communities to determine where wetland boundaries exist.

Mini-Expedition: Explore a refuge habitat in detail by studying a small section of it and recording your observations.

Sedimentation Observations: Discover how much rock, sand, and silt is deposited in the waters of the refuge.

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