NCCSP

As wildland fires increasinly grab national attention, the call to "do something" gains almost inexorable momentum.  To reduce interface home loss, the obvious thing "to do" is increase the prevalence with which homeowners follow defensible space rules - after all, 90% of homes with nonflammable roofs and a defensible space survive even hot burning, high-intensity fires.

But, what about our forests, rivers and streams?  Are they, too, threatened by changes in fire behavior or are they more threatened by the actions taken to address fire threats?  Our two cover features address these ecological questions, one from a terrestrial and the other from an aquatic perspective.

FEATURE ARTICLE

RESTORING THE RESILIENCY OF AQUATIC SYSTEMS TO FIRE

by Cindy Deacon Williams, NCCSP Director of Aquatic Science

When thinking about fire and conservation of rivers, streams, and the fish and other species that call the forest’s wet spots home, riparian areas are of central concern.  Throughout the West, these important transitional zones linking terrestrial and aquatic systems have suffered declines of 50% and many of the remaining riparian areas are seriously degraded.   Past logging, grazing and other management practices have led to loss of riparian trees and shrubs that provide habitat and other resources to a disproportionate number of wildlife species, and dramatically affected native fishes, amphibians, and invertebrates by causing increased siltation, elevated temperatures, and decreased nutrient and large wood inputs to streams.

Some claim similar impacts occur when fire burns up a canyon and devastates streamside riparian areas.  However, natural systems are adapted to short but intense disturbances, like wildfire, but not to chronic inputs of sediment and other continuous disturbances associated with road construction, felling trees, and decking and transporting logs. 

Furthermore, research indicates fire frequency generally has been lower and severity more moderate in riparian areas when compared to adjacent uplands.  Clearly, under some conditions (e.g., extended drought, high winds and temperatures) fires can have substantial direct effects on streams and riparian systems and even may threaten the persistence of local fish populations, particularly those that are small and isolated.  However, even in such extreme circumstances, major new efforts to actively manage fires and fuels may turn out to be a threat rather than a benefit to native fish and aquatic habitat conservation; especially when treatments focus on addressing symptoms (e.g., high fuel loads) rather than restoring natural processes. 

So, what should be done?  First, we need to undertake restoration projects that create aquatic conditions that are more resilient to fire.  The most effective approach is likely to be pre-fire restoration efforts that promote persistence of fishes by addressing habitat loss and fragmentation, channelization, chronic sediment input, accelerated erosion, and changes in natural flow regimes.  Activities should include fish passage barrier removal, habitat recovery, and road decommissioning, restoration, and improvement.  Fish do remarkably well when facing fires if the watershed and their in-stream habitat are in reasonable shape to begin with and they don’t face significant barriers to up- and downstream movement.

Second, we must ensure that restoration thinning projects don’t create new problems for river and stream function.  No treatments should utilize heavy equipment on steep landslide-prone slopes, occur on skeletal soils or soils where natural forest regeneration is limited, or encroach into unroaded portions of the landscape.  All big, old trees should be retained where thinning does occur, and all operations should be conducted from existing roads and landings.  As a reasonable precaution, thinning generally should not treat riparian and wetland areas.  If past riparian grazing, logging or other management has impaired hydrologic function or degraded aquatic or riparian habitat, ecologically based treatment to restore aquatic function may be appropriate.  But such treatments must be targeted at restoring aquatic function and be designed in accordance with standards, guidelines and objectives of the Aquatic Conservation Strategy of the Northwest Forest Plan, and PacFish and InFish in the Eastside Scientific Panel Study. 

At the most fundamental level, recovering riparian and in-stream habitats, restoring natural flow regimes, and re-establishing connectivity are critical to increasing the ability of aquatic systems to recover from disturbances.  This is true not only for fire, but also as preparation for the climate change-induced likelihood that our rivers and streams will face more frequent, higher-intensity run-off events.  The challenge is to deal with the stresses and risks associated with fire without creating new or exacerbating existing problems in the aquatic environment, and without making it more difficult for our rivers and streams to handle the other stresses that confront them.

When watershes and in-stream habitat are in reasonable shape to begin with, fire generally is not a problem for aquatic ecosystems.  Photo credit (top photo): Cindy Deacon Williams