Arizona’s Largest Wildfire Poses Challenges and Opportunities for Rare Aquatic Species

by Jeremy Voeltz

On May 29, 2011, the Wallow Fire ignited in the Apache-Sitgreaves National Forest in the rugged Bear Wallow Wilderness Area of eastern Arizona. Fueled by high winds, high temperatures, low humidity, and extremely dry forest conditions, the raging wildfire charred over 100,000 acres (40,468 hectares) within days. When it was finally contained over six weeks later, the fire had consumed over 538,000 acres (217,720 ha)—making it the largest wildfire in Arizona history.

While more than 6,000 firefighters worked to save structures and build fire lines to control the massive fire, several agencies involved in the Apache trout recovery program worked behind the scenes to identify potential impacts to the federally threatened Apache trout (Oncorhynchus apache) and prioritize possible actions for salvage operations (the removal of trout from streams where it is expected they will die) and artificial fish barrier modification.

Fearing significant fish kills as a result of ash and sediment flows caused by summer monsoons, the U.S. Fish and Wildlife Service, in partnership with the U.S. Forest Service, Arizona Game and Fish Department, and White Mountain Apache Tribe, began monitoring priority Apache trout populations, specifically the natural population in Soldier Springs Creek, the reestablished populations in Fish Creek; the South Fork, West Fork, and East Fork of the Little Colorado River; and the proposed recovery streams of Bear Wallow Creek and Conklin Creek—all located either completely or partially within the burn area.

Initial reports feared that Apache trout recovery would be significantly stalled, or even reversed, as a result of the Wallow Fire. While the short- and long-term effects on the recovery streams within the burned area are still not fully understood, field crews expect to have a better idea later this fall. Once the severity of the damage is assessed, discussions regarding the next steps for the Apache trout recovery populations affected by the fire will begin.

The fire burned east of the stronghold of Apache trout populations found on the Fort Apache Indian Reservation, and the recovery streams that do occur within the burn area do not represent any significant genetic material that is not represented in non-burned populations. Even with the possible short-term loss of a couple recovery streams, there is hope for the species.

The forested areas surrounding Apache trout streams had a historical fire cycle. A number of factors, including fire suppression for fear of uncontrollable and destructive conflagrations, have interrupted this cycle for over 100 years. Several areas within the burn zone had become extremely overgrown and contained an agglomeration of dead and downed trees and other debris – ideal fuel for wildfires.

"We knew these areas would burn eventually," said Mike Oetker, Assistant Director for Fisheries in the Service’s Southwest Regional Office. "We didn’t plan for it all to burn at once. Even with that happening, the fact that we did not have to take drastic efforts to save Apache trout shows that our recovery plan is working."

In addition to fuels reduction, which will help prevent or lessen the intensity of future wildfires in the area, the Wallow Fire may also benefit Apache trout recovery by reducing a number of other threats to the species. It is expected that nonnative fishes that compete with Apache trout, specifically brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss), will be reduced in areas due to fish kills from the ash-laden run-off. At the same time, some artificial barriers may benefit from a short-term increase in higher sediment flows, which can seal crevices in the gabion basket and rock structures and make them more secure at preventing upstream movement of nonnative fishes. Finally, habitat-based funding sources such as the National Fish Habitat Action Plan’s Western Native Trout Initiative and the National Fish and Wildlife Foundation’s (NFWF) Apache Trout Keystone Initiative will provide significant funding for future habitat restoration projects within the burned areas.

While fire is a natural part of these ecosystems, extremely large fires that have occurred in the Southwest over the last 20 years were historically rare. With a fire this immense, the number of terrestrial and aquatic species affected is large. In addition to analyzing and responding to threats to Apache trout, partnering agencies completed salvage efforts for the federally threatened Little Colorado spinedace (Lepidomeda vittata) and loach minnow (Tiaroga cobitis); the roundtail chub (Gila robusta), a candidate for Endangered Species Act protection; as well as a number of other rare aquatic species. Fisheries managers across the partnering agencies, and other organizations including Trout Unlimited and NFWF, have shown unwavering cooperation and strong partnerships in dealing with the threat of wildfire and the impacts on native aquatic species.

Jeremy Voeltz, a fishery biologist in the Arizona Fish and Wildlife Conservation Office, can be reached at jeremy_voeltz@fws.gov or 928-338-4288, ext. 23.