Wildfire and sedimentation could help Gila trout make a comeback

 

After the nearly 300,000-acre Whitewater-Baldy fire tore through the Gila Wilderness last summer, biologists from the U.S. Fish and Wildlife Service and the U.S. Forest Service . The team traveled to remote tributaries of the Gila River to collect any Gila trout, one of New Mexico’s threatened fish species, that had survived the initial blaze. The approaching monsoon season would likely mean death for any remaining fish, as rain would erode the fire-scarred land, flooding the streams with suffocating ash and soil. The rescued fish were flown by helicopter to a hatchery in northern New Mexico where they will stay until the streams can support them again.

This all may sound like bad news, but for the Gila trout, there is a silver lining. A flood of sedimentation following the fire cleared the streams of the non-native rainbow and brown trout that are serious obstacles to improving Gila trout populations.

Jill Wick, Gila trout biologist with the New Mexico Department of Game and Fish, is part of the team assessing the impact of last summer’s fire. She says the fish die-off is a double-edged sword.  Previous work the team had done was lost, with the fire wiping out entire populations of Gila trout. On the other hand, with the rainbow and brown trout removed from the streams, biologists will be able to reintroduce captive-bred Gila trout and expect a better survival rate.


The plight of the Gila trout sounds like that of so many other protected species: human activity on the landscape, habitat degradation, and introduction of exotic, competitive species like rainbow and brown trout have all contributed to its decline. Wick has been working closely with the scientists within the U.S. Fish and Wildlife Service, the Gila National Forest, and from the University of New Mexico -- a group she calls the recovery team -- to understand the Gila trout’s habitat needs and maintain captive breeding populations for reintroduction.

The Whitewater-Baldy fire was one of the most recent incidents in a decades-long story of Gila trout recovery work. In 1966, populations were small and precarious enough to be considered federally endangered. Under a management plan, the fish rebounded enough that in 1996, the species was down-listed to threatened.  Some members of the recovery team have been working on the project for more than 20 years, conducting captive breeding programs in northern New Mexico and building physical barriers along portions of streams to isolate wild populations from predation and hybridization with non-native rainbow trout.

The Gila trout isn’t the only species to benefit from a wildfire silver lining. Though wildfires consume many Westerners’ thoughts and government resources each summer, many Western ecosystems have actually evolved with fire, with certain tree species like lodgepole pine and aspen benefiting from heat and thinning from moderate fires. Some vertebrate species, like the black-backed woodpecker, thrive in the unique habitat created by burn areas. Still, the trend toward bigger, hotter fires poses challenges.

Year after hot, dry year, new fires across the West steal previous years’ titles as the biggest or the most destructive. In 2011, the in New Mexico’s Jemez Mountains became the state’s largest fire at 156,593 acres. The following summer, the Gila’s nearly doubled the number, burning out at 297,845 acres. Meanwhile, the destroyed 254 buildings across the state near Ruidoso, N.M., also last summer, earning the label “most destructive.”

As the Gila trout recovery team makes key decisions later this summer, the potential for future fires may enter the discussion, Wick says. The first management plans were written “before anyone anticipated that you could have a 300,000 acre fire,” she says. Other ecologists are anticipating significant changes to forest structure due to climate change as well and are needing to make management plans with those predictions in mind. Wick and her team are still trying to figure out what a changing climate might mean for their project.

Another challenge for the recovery team is access to habitat. It’s harder for them to manage rainbow and brown trout on streams that pass through private land and towns, as access and management techniques are restricted. Whitewater Creek, which flows through the town of Glenwood, N.M., is one such area. The creek begins on land that experienced some of the hottest burn. Closer to the Catwalk National Recreation Area, where the fire was less severe, Wick says the entire fish population was lost. And in a way, this is good news. The creek is attractive to the recovery team, with 14.5 kilometers of potential Gila trout habitat. However, it wasn’t feasible to remove the non-native trout because of its location near human populations. The die-off from the fire has done that for them, says Wick. “It couldn’t have been done any other way.”

Katie Mast is an editorial intern at NewTowncarShare News.