OUR GEM: Ecosystem services that wetlands provide

Wetlands refer to the watery transition zones between surface water and dry land. They can be wet year-round or only during certain parts of the year, such as following spring runoff. Essential parts of a wetland include aquatic plants specifically adapted to live in fully saturated environments. In the Inland Northwest, non-tidal wetlands are prevalent, unlike coastal regions that support tidal wetlands. 

Nature’s water filters 

Wetlands act as natural water filtration systems that trap and prevent pollutants, sediments and nutrients from entering waterways. Often, wetlands are found at the confluence (the meeting point) of faster-moving water from streams, rivers, or stormwater runoff before the water continues to the main body of a lake or pond.

These wetlands provide what are known as ecosystem services, where the ecosystem, in this case, the wetland, provides a service such as water filtration at no cost to humans.

When faster-flowing water meets a wetland, the pace at which the water flows slows down, allowing sediments and particles to settle to the bottom of the wetland. Nutrients from fertilizer application, manure, leaking septic tanks and municipal sewage that are dissolved in the water are often absorbed by plant roots and microorganisms in the soil. Other pollutants stick to soil particles.

Some types of wetlands are so effective at this filtration function that environmental managers construct similar artificial wetlands to treat stormwater and wastewater. When nutrient-laden water and sediments meet wetlands, the slow-moving water allows these particles to settle out and allows water-loving, nutrient-needing plants to flourish. This feeds the diverse array of aquatic life that thrives in wetland environments and allows the filtered, fresh water to pass through either directly to lakes, streams and rivers, or even directly into the ground, refilling the aquifer. 

Economic benefits of wetlands 

Wetlands provide excellent stormwater infrastructure. When water runs off paved surfaces, it often flows fast and is filled with particles. Wetlands act as stormwater buffers for many streams in the Panhandle region.

Have you ever noticed man-made depressions in the earth filled with reeds and tall grasses? These are likely stormwater infrastructures built to replicate a natural wetland and pre-treat stormwater before it enters streams. Natural stormwater infrastructure keeps water discharging into streams and rivers clean.

Riparian wetlands, found along the floodplains of streams, also have the ability to substantially mitigate flood damage. Wetland soils and vegetation act like a sponge, storing excess run-off and attenuating the amount that is delivered to waterbodies. This allows wetlands to act as one of Earth’s natural “flood insurance policies,” preventing millions of dollars in flood damage annually. 

Wildlife habitat oasis 

Although less than 1% of Idaho’s land is considered wetland, more than 75% of Idaho’s species rely on a wetland habitat at some point in their life.

Wetlands are safe places for fish to spawn in relatively slow-moving or stationary waters. They provide excellent food sources for larger wildlife, like moose and deer, and offer pristine birding habitats.

Water lilies, pondweeds and horsetail are some of a moose’s favorite foods. Red-winged blackbirds build their nests in wetlands, relying on the tall reeds as perches to hunt for insects. Great blue herons can be found waiting patiently on wetland edges for fish to pass by.

Amphibians such as the Columbia spotted frog lay thousands of eggs in wetlands, which develop into tadpoles. Reptiles such as the northern painted turtle can be found sunning on floating logs in many wetlands on a hot summer day. Macroinvertebrates and microorganisms thrive in wetland ecosystems and form the base of the aquatic and terrestrial food chains. 

Wetlands prevent excess pollutants from entering waterways, provide excellent habitat for wildlife, and are aesthetic features of our natural landscape.

As with many waterways in Idaho, agencies, municipalities and individuals recognize the importance of wetlands as water bodies, and maintaining their importance for protection is essential for preserving wetlands ecosystem services in the future.

The next time you see a wetland, consider for a moment what ecological service that wetland is providing, likely at very little cost to you. 

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The Our Gem Coeur d’Alene Lake Collaborative is a team of committed and passionate professionals working to preserve lake health and protect water quality by promoting community awareness of local water resources through education, outreach, and stewardship. Our Gem includes local experts from the University of Idaho — Idaho Water Resources Research Institute, Coeur d’Alene Tribe, Idaho Department of Environmental Quality, the Basin Environmental Improvement Project Commission, Kootenai Environmental Alliance.

Meg Wolf is the Interim Assistant Director/Idaho Water Resources Research Institute, University of Idaho.