On my recent stop at the Gila River Bird Area (see Nighttime Visitors), I was reminded again what a dynamic, ever-changing place it was. The Gila River was still receding from a significant flood just 2 weeks prior, in which up to 10 inches of rain dumped in the heart of the Gila Wilderness during a 9 day period; most of the rain fell in 48 hours. Rivers crested at near-record levels, roads were wiped out, and the famous catwalk area near Glenwood was completely destroyed. Much of this area had been impacted by recent wildfires as well (see Before the Whitewater-Baldy Fire). Ten inches of rain anywhere in the desert is a lot, but on top of damaged soil was more than the river system could bear.
The willows show the high water mark from the flood, as it stripped the leaves off the branches.
The Gila River is one of the Southwest’s great rivers. Beginning its journey high in the Gila Wilderness in western New Mexico, it’s 3 major forks drain most of the wilderness before heading west into Arizona. There it picks up the San Francisco River, which drains the northern Gila ecosystem. The Gila then continues west toward Phoenix, picking up the Salt River which drains much of Arizona’s Mogollon country (the Mogollon rim is a high volcanic escarpment that effectively separates the Sonoran Desert from the Colorado Plateau). But agriculture and development sucks the river dry here, so that it seldom completes its journey across the Sonoran Desert to the Colorado River and on to the Sea of Cortez. But for now, its headwaters are protected, but still subject to the whims of Mother Nature.
So in late-September, the rivers rose. And rose and rose. Sweeping roads, bridges, cars downstream. Picking up rocks and debris and scouring out years of vegetation that had established on the banks of the river since the last flood. Much like the fires, it was inconvenient for us, and tragic for some of the organisms in its path, but this is the way the ecosystem functions. It thrives on catastrophe.
The mountains of the southwest, including the Mogollon Rim country that comprises most of the Gila headwaters, are fire-prone, perhaps even fire-dependent ecosystems. The area is prone to drought, subject to the vagaries of Pacific ocean currents. Dry forests generate kindling for the lightning storms that accompany the summer rainy season. Although the tremendous acreage burned in recent large fires (almost 2 million acres of forest burned in Arizona and New Mexico in the last 11 years) is reportedly due to fire suppression, the fact that these fires were able to consume so many acres in spite of advances in fire fighting techniques and equipment should tell us that we are really not all that effective at suppressing fires. In addition, the Gila National Forest has been letting fires burn in the Gila Wilderness, plus setting “controlled burns.” So the Gila Wilderness is likely the best approximation we have of what a southwestern ecosystem with natural fire looks like. The results of this policy are evident in an overview of the forest. Scattered among the pine-oak-juniper covered slopes are open parklands and meadows, likely the results of past high-intensity fires.
Smoke from a wildfire blankets the wilderness, early July 2005.
On the north side of the Gila Wilderness, Bursum Road follows a long ridgeline between Willow Creek and Snow Lake. Evidence of a hot burn lines both sides of the road (or at least it did before the Whitewater-Baldy Fire). Long stretches of black tree skeletons give evidence of how hot the burn was. The fire was some 10-15 year ago and killed large patches of trees. New growth is visible where they forest once stood, as oaks, mountain mahogany, and grassy fields reclaim the burned soil. Given time, or another fire, some of these dead stands of trees will become open parkland, at least for a while.
Old burn visible from Bursum Road. September 2010.
But back on the Gila River, the side channels that had been scoured by the recent flooding created some of the best tracking substrate I’ve ever seen. Tracks of mountain lions, foxes, coyotes, coatis, skunks, raccoons, grasshoppers, pocket gophers, salamanders, toads, turkeys, deer, squirrels, birds, and javelina all decorated the muddy shores and side channels of the river.
Trail of a skunk dragging a wet tail after emerging from the river. Also tracks of a pocket gopher and raccoon.
And the singing insects, what I was actually there for, were singing like crazy, with loud choruses of cicadas backed up by grasshoppers. As evening slowly settled over the river, the crickets chimed in, and for a short period of time, they all were singing in a lovely orthopteran orchestra. If you listen closely, and your hearing is somewhat intact, you can hear the high-pitched clicking of a tree-cricket.
The river can handle the fires and floods. What really messes it up, though, are the mines, dams, roads, subdivisions, overgrazing, and over-logging.
Recording notes: Recorded with a Sony PCM-M10 with an Audio-Technica AT2022 mic with a Felmicamps SK 3.5 pre-amp.