FOREST NOTES

By Charles Babbitt

This summer’s Aspen fire in the Catalina mountains near Tucson has burned 70,000 acres mostly in mixed conifer and ponderosa pine habitat. The area was probably long overdue for a major fire. It is thought that stand replacing fires occurred naturally in the mixed conifer forests of Southeastern Arizona every 20-30 years. Decades of fire suppression have disrupted the natural fire cycle leaving forest floors clogged with excess fuels ready to explode during periods of drought.

Fire and bark beetle infestation remind us that we remain in the grip of a severe drought. If these conditions persist or worsen it is reasonable to expect major fires in virtually all of Arizona’s mountain ranges in the coming years. If global warming continues, we may live to see significant shifts and changes in vegetative distribution.

Contrary to public perception, big fires like the Rodeo-Chediski and Aspen fires do not burn through the forest leaving a large swath of lifeless destruction. Photographs and visits to the Rodeo-Chediski fire and preliminary views of the Aspen fire show typical fire behavior that leaves behind an irregular mosaic of burned and unburned forest. Fires burn random holes into the forest and leave behind islands, stringers and blocks of unburned trees.

We sometimes forget that our forests evolved with fire and that they need fire to remain healthy. On a recent visit to the Pumpkin Fire (2000) and the Hochdoeffer Fire (1996) north of Flagstaff many signs of change and recovery can already be seen although those fires are less than a decade old. Young aspen trees are springing up and ground vegetation is thriving because of increased sunlight. Standing burned snags provide ideal habitat for bird and insect species. Looking down on the Leroux Fire (2001) from the San Francisco Peaks one can see holes burned into the forest by the fire.  These new mountain meadows will slowly fill in with a succession of plants and trees until a new fire cycle repeats the process.  Fires do not destroy forests, they change them.

The Bush administration and its allies in congress are using fire and the threat of fire as an excuse to gut environmental laws in order to facilitate the commercial logging of our remaining big trees and old growth forests. The Bush backed  McInnis bill dubbed the “Healthy Forest Restoration Act” recently passed the house and is now awaiting action by the senate. Among other things, the bill allows agencies to ignore environmental alternatives to their fuel reduction projects. For that matter, it does even require a “no action” alternative, something fundamental to the NEPA-EIS process. The bill reduces opportunity for public comment, eliminates the right to appeal hazardous fuel projects and imposes limitations on judicial review and injunctive relief. Because of its broad and vague definitions the bill’s provisions arguably reach most Forest Service and BLM lands. While the Bush administration pushes forward with logging projects, legitimate forest thinning and fuel reduction projects next to fire vulnerable communities go unfunded

5

IF FISH COULD FLY (OR A FISH STORY)

By Laurie Nessel

As I gaze at the stained glass window I made 15 years ago, inspired by a hike in Aravaipa Canyon, I cringe at the incongruous fish looming in the foreground. Below the flicker, Mariposa lily and other native species, I plopped a striped bass. My ignorance of native fish at the time was hardly unique. Even today, few Arizonans, anglers included, can name one native fish. These fish face an upstream battle. What had taken millennia to evolve is being wiped out in mere decades. 

Like many of you, I was attracted to birds because of their beautiful plumage, song and visibility.  Learning about their amazing behavior and survival adaptations added to the allure. Fish are largely inaccessible, making them difficult to study and enjoy. But they are no less remarkable than birds and they share some similarities. Some species acquire bright breeding colors to their already dazzling, iridescent scales. They glide gracefully and effortlessly like a hawk on the wing, school like a flock of waxwings, and turn as abruptly as do hummingbirds. Some, such as the Colorado pikeminnow, even migrate. Fish require varied habitats, in water that ranges from turbulent to placid, slightly salty or fresh, silty or clear. Some can withstand extreme variations in temperature, flow, elevation and quality. Some are voracious predators, others mostly vegetarian. They have courtship displays and build nests (depressions in pebbly river bottoms called “redds”). Males of some species aggressively defend territory and young. Some fish are diurnal and others, such as the Desert sucker, are nocturnal-possibly evolved to evade Blackhawks and Zone-tails. Different body shapes are adapted to different stream characteristics- turbulent or laminar flow, calm pools, sandy or rocky bottoms. They have superb senses of smell (like the Turkey vulture) and sight and use hearing to detect predators and to seek prey and mates.

Their lifespans range from several years for the desert pupfish, to over 40 years for the Bonytail. The desert pupfish is among the smallest at 1 ½” while the Colorado pikeminnow, the largest N. American minnow, reaches nearly 6 feet in length and can weigh 100 pounds. Fish change morphology in response to environment, like the Willow ptarmigan. Adult Roundtail chubs vary from 6”-25.5”. The speckled dace are rounded, speckled, with large scales in still pools of Aravaipa Creek but elongated, depigmented with small scales and long fins in turbid Paria River. 

The Longfin dace, the most widely distributed native species, know and seek out the deepest section of a stream and survive in isolated pools when water levels drop. They disperse throughout a drainage when flow recurs. They have been known to survive in minimal water beneath algal mats. Year round spawning increase their chance of survival. The desert pupfish survives from below sea level to 4900’elevation in the upper San Pedro. Pupfish mature rapidly and spring fry can reproduce mid-summer. Topminnows deliver live young!

Arizona’s native fish evolved over 5-10 million years to thrive in the harsh, arid desert. They are remarkably adapted to extreme changes in environment, but were not prepared for the drastic events that have occurred over the past century.  They are one of the world’s most imperiled taxa. Of 36 species, 19 are threatened or endangered. Eight are extirpated. Some of these fish weren’t described 

until the 1980’s very little are known of others, and still others became extinct before being described.

Native fish have been pushed toward extinction by water diversion, river channelization,  dewatering, habitat degradation, exotic species and other human caused factors. Water diversions have removed over 90% of the river system from Arizona in the last 100 years. Dams interfere with migration and trap sediment that protect banks. Water in desert streams seep into the porous valley floors and is stored near the surface. During dry spells, this water seeps back into the channel creating perennial streams or isolated pools where fish survive. Extensive water pumping drops water tables, strand fish and desiccate eggs and vegetation.

Hundreds of fish, including the endangered Rio Grande silvery minnow, were killed within the Bosque del Apache National Wildlife Refuge in New Mexico as water is diverted for agricultural and municipal uses. 

Even where natural streams survive, natives are threatened. Aquatic and streamside plants that stabilize banks and provide nutrients and oxygen are trampled by livestock that congregate in streams. They forage on cottonwood and willow saplings, preventing succession (and destroying willow flycatcher habitat).  Loss of vegetation minimizes cover for lurking fish and exposes water to sun. This, in turn, creates higher temperatures, more evaporation, greater salinity and concentrated pollution. Streams flow wider, shallower and warmer. Excess nutrients from livestock waste or agricultural runoff combined with warm temperatures cause algae blooms that suffocate fish. Hoof ruts fill with stagnant water forming vector habitat. Trampling also damages the subsurface zoological community, an important food source for fish. Displacement of rocks alters shelter for macroinvertibrates. Stock tanks can drain desert springs. 

Logging, road building and intense forest fires inhibit water absorption causing sediment and ash to fill rivers and suffocate fish. 949 Gila chub were removed for their safety from Sabino Creek during the Aspen fire in July.

There are more than twice as many introduced fish species than native in Arizona. Non-native species stocked for game, insect control or as forage, predate, hybridize or outcompete the natives. Bonytail and razorbacks haven’t recruited young for 20-30 years due to predation by introduced exotics. The Monkey Spring pupfish and Gila chub, desert springs species, were extirpated within months when largemouth bass were introduced. There being no other known location of  Monkey Springs pupfish,  this species is our first casualty. Other devastating exotics include Giant salvinia, a water fern, New Zealand mudsnails, crayfish and Whirling disease, a parasite that attacks native trout. 

What can be done? We can advocate for the protection and restoration of habitat. Refugium habitats can protect populations of native fish and provide stock for reintroductions. Check out the refugia at The Phoenix Zoo, Desert Botanical Gardens and Boyce Thompson Arboretum.

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