The Osprey: Rewilding the White Salmon River
Sometimes it seemed as if the entire West Coast was on fire this summer. As of late September, about 4 million acres had burned in California, more than a million in Oregon and 626,000 in Washington. As of this writing, California wildfires have destroyed more than 8,000 structures and killed at least 26 people. In Oregon, those numbers are 3,000 and 10, respectively. Washington State has fared a little better with just under 400 buildings destroyed and one reported death.
Driven by a combination of excess fuel in the forests, high winds, and most importantly, increasingly drier environmental conditions resulting from climate change, these fires erupted into conflagrations that in many cases were unstoppable by humans. Here in Oregon, major fires raced down Cascade Mountains canyons including the North Santiam, McKenzie and North Umpqua — all important salmon, steelhead and trout watersheds.
When the smoke clears — literally and figuratively —thorough damage assessments will need to be made to fish and wildlife habitat along with human structures and property.
While wildfire’s destructive properties are emphasized in news reports, surprisingly these fires can be a mixed bag for fish, with both negative and positives impacts. The traditional view has been that wildfires destroy fish habitat and kill fish, yet wildfires are a natural-occurring phenomenon and fish have been persisting in spite of fires for millenia.
ALSO IN THIS ISSUE
• CANADA’S BROKEN FISHERIES AGENCY
• MELTING GLACIERS, CHANGING FISH HABITAT
• REFLECTIONS ON COLD WATER REFUGIA
• KEEPING POLITICS OUT OF SALMON AND STEELHEAD RECOVERY
Wildfires certainly do damage habitat, including destroying riparian trees that provide shade and denuding slopes resulting in landslides and siltation of streambeds.
But those landslides will also dump rocks, logs, stumps and other natural debris into streams to begin the proces habitat rebirth. Warmer water temperatures in the aftermath of fires can cause trout, salmon and steelhead to grow faster and mature earlier, although population densities may be lower.
Interestingly, recent research comparing riparian areas that experienced high severity fires over more moderate fires have found that the former sites show an increase in the emergence of adult aquatic insects, suggesting there may be a kind of “fire pulse” that boosts insect productivity.
A critical aspect for fish to survive wildfire is the need to have options when fires erupt, such as the availability of coldwater refugia and other high quality habitat.
Researchers are only beginning to study and understand the relationship between fish and fire. But as fires increase in numbers and severity, as they are expected to do, especially in salmon and steelhead country, wild fish managers and conservationists are going to need a full understanding of these dynamics if fish are able to continue to survive this natural processes that humans are making much worse.