“As salmon go, so go we. Salmon is connected to everything in our lives. We are committed today to do everything we can to the preservation of this incredible blessing. I was going to say ‘resource,’ but I think blessing is the right way to think of salmon in this state. I am committed to working with everyone … on this divine mission we are on.”
Washington Gov. Jay Inslee
2021 State Salmon Recovery Conference
Riparian, or streamside, habitat is essential to both our region’s salmon recovery efforts and climate change resiliency. Salmon continue to decline in western Washington because their habitat is being lost and damaged faster than we can restore and protect it, as a result of development, farming and past logging practices.
What Does Healthy Riparian Habitat Look Like?
Treed riparian areas provide shade to help maintain cold stream temperatures. Water temperatures nearing 70 degrees can be fatal to salmon. About 1,800 miles of streams in western Washington do not meet state standards for water temperatures.
Large Woody Debris and Instream Habitat
Large trees in riparian areas are a major source of instream large woody debris that captures gravel, creates spawning beds, builds cold water pools for salmon to rest, and provides protection from predators. Large woody debris also helps form side channels and islands that provide refuge for salmon from high stream flows.
Roots prevent banks from eroding during floods and large storms while keeping sediment out of streams and protecting incubating salmon eggs.
Leaves and stems from riparian vegetation fall into streams and provide nutrients that support aquatic food webs.
Treed riparian areas capture and filter sediment, concentrated nutrients, toxic chemicals, and other pollutants from sources like farms, lawns and roads.
Streamside Buffers Have a Formula
A scientific standard for forested riparian buffers is called site potential tree height (SPTH). It is calculated using the maximum height of the tallest dominant species of trees – usually 200 years or older – in a streamside location. When converted to buffer widths, the distance ranges from about 100 to 300 feet depending on soil conditions, rainfall and other factors.
How Does Site Potential Tree Height Help Habitat?
Mitigates human disturbances
In degraded ecosystems, every established and newly planted tree contributes to protecting and restoring riparian and aquatic ecosystems.
Increases buffer resiliency
Riparian ecosystems are dynamic, and catastrophic events are unpredictable. Narrow buffers are at higher risk of being destroyed than large buffers from flood, fire and windstorm disturbances. A single event can destroy a stand of riparian trees that require hundreds of years to grow back. Anything less than full riparian protection adds uncertainty and risk to restoring salmon and other resources.
Increases climate change resiliency
Climate change is increasing pressure on stressed aquatic ecosystems. Floods are more frequent and intense, droughts are longer and drier, and stream temperatures are rising. Forested riparian areas provide cooler microclimates instream and for the surrounding environment. For fisheries already on the brink of disappearing, establishing and protecting fully functioning riparian ecosystems is absolutely necessary for their continued survival.
Increases opportunities for carbon sequestration
Riparian areas capture and store carbon in their vegetation and soil, such as carbon dioxide, the most common greenhouse gas contributing to climate change.
The key to recovering salmon is to restore lost riparian forests and protect existing habitat. Still, every single report over the past few decades says the same thing: Our ecological health is getting worse. Our salmon populations continue to decline because their habitat is being lost faster than it can be restored.
Our current approach to salmon recovery simply isn’t working. We know what needs to be done to protect and restore salmon habitat, but it isn’t reflected in land-use laws such as the Shoreline Management Act and Growth Management Act. At best, these laws attempt to balance development with conservation by trading environmental impacts in one place with improvements elsewhere, not necessarily in the same watershed.
These management laws are supposed to require “no net loss” of ecological function. But there is no agreed-upon legal definition for “no net loss” and no way to evaluate conditions or changes over time.
As a result, the status quo of habitat loss continues unabated, in part through variances and exemptions to these acts.
We need to take a hard look at how we live here, so that we can all continue to thrive in a way that respects the environment.
Protecting existing habitat and restoring degraded riparian areas with uniform, science-based riparian management to protect salmon and their habitat offers the best chance of achieving our goal. History teaches us that our salmon recovery mission will not be successful without the deployment of new tools and advanced strategies.
Let this hard work continue in earnest.
Learn more at riparianhabitat.org.