Keystone Species

Some river species have impacts far beyond their numbers. Pacific salmon are born in freshwater streams, migrate to the ocean, then return to spawn and die in the same stream. Their decomposing bodies deliver marine nutrients — nitrogen and phosphorus — deep into forest ecosystems.

Bears, eagles, and other predators carry salmon carcasses into the forest, where the nutrients fertilize trees up to 500 meters from the riverbank. Studies show that trees near salmon streams grow up to three times faster than those near streams without salmon. Nitrogen isotopes from the ocean have been found in tree rings miles from any river.