Fossil Creek: A Fragile Ark

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Fossil Creek has become a world-class refuge for wildlife — a veritable Noah’s ark for rare and endangered species both above and below the turquoise-blue waters of the travertine-laden creek.

The Forest Service hearings in Rim Country focused on management plans drew lots of people upset with the threat to permanently shut down access to the creek from Strawberry. Most of those protesters either wanted to have access to the spring-fed creek with its miles of waterfalls and deep pools — or make money from the roughly 90,000 people annually who descend on the creek on the weekends.

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Fossil Creek

But the Fossil Creek Wild and Scenic River Resource Assessment makes it clear just what an extraordinary refuge for fish, reptiles, birds, mammals and amphibians that creek has become in the seven years since Arizona Public Service shut down a historic hydroelectric generating plant and returned the flow of water to the creek bed.

The creek’s role as an unparalleled wildlife refuge stems from the extraordinary properties of the water that gushes from a series of springs at the head of the canyon and the pristine qualities of a riparian area that seems uniquely reinvented.

Start with the water itself, which emerges from 60 springs in a 100-foot-long section of the creek bed. The flow of these springs totals about 50 cubic feet per second, an astonishing, utterly consistent gush of water in an arid region. The flow is only a little less than the 65 cubic foot per second gush of Havasu Spring, which spawns a world-famous travertine stream in the heart of the Grand Canyon.

Sometimes, the creek also carries great floods of runoff, with a peak recorded flow of nearly 900 cubic feet. But mostly, it just carries the crystal clear, blue-tinted, travertine-saturated springwater.

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Photo courtesy U.S. Fish & Wildlife Service

Northern Mexican gartersnake

No one knows for sure how long ago the water that gushes from those springs fell as rain and snow. The water has seeped through more than 1,000 feet of fractured limestone and may have spent thousands of years on that journey. In the process, the water dissolved great quantities of calcium carbonate, the remains of ancient sea creatures that accounts for most of the mass of the limestone. Buried deep beneath the rock, the mineral-rich water warms to a constant 72 degrees and holds dissolved limestone in solution at pressures 150 times greater than the atmosphere. As a result, the calcium carbonate in solution readily precipitates out as the mineral-laden water tumbles over roots and stones and waterfalls.

Only a handful of streams have the chemistry necessary to build the travertine formations that have grown rapidly since the water returned to the stream bed. An estimated 13 tons of travertine precipitate out along the stream every day, constantly building natural check dams and formations.

Riparian areas comprise less than 1 percent of the land in the western United States, but more than 80 percent of the wildlife depends on riparian areas for some critical portion of their life cycle. Deep in a remote canyon, a riot of native trees crowds the creekside, including Arizona sycamore, Fremont cottonwood, willows, Arizona alder, mesquite, velvet ash, Arizona walnut and others — at least 166 species of permanent plants and 314 species of flowering plants and ferns. The creek harbors at least eight “sensitive and rare” plants.

The fish

The waters of this remarkable stream now provide one of the last refuges for a host of native fish. The U.S. Fish and Wildlife Service and the Arizona Game and Fish Department teamed up to rid the stream of non-native fish before returning the main flow of the springs to the stream bed.

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Contributed photo

Colorado Pikeminnow

As a result, Fossil Creek remains a refuge for native fish matched only by the spring-fed stretch of the Little Colorado River deep in the safety of the Grand Canyon.

The Resource Assessment concluded, “Seven species are federally listed as endangered, threatened or candidate for listing. Fossil Creek is presently home to the largest number of native fish species in Arizona.”

The creek offers the perfect diversity of habitats for the crowd of native fish driven out of most other streams in the Southwest by water diversions and non-native competitors like trout, bass, catfish and carp. For instance, from only a handful seven years ago, the number of chub — also called Verde trout — has rebounded to more than 20,000.

Other wildlife

The spring water that harbors the state’s richest array of endangered fish also shelters a great variety of birds, reptiles, mammals and amphibians.

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Photo courtesy U.S. Fish & Wildlife Service

Bald Eagle

Fossil Creek has already become a birder’s paradise, as rich as the birding Meccas in southeastern Arizona where eco-tourism has become an economic mainstay.

Biologists have recorded 200 different species of birds, mammals, reptiles and amphibians, but the habitat has the potential to support 300 additional species — including endangered species like the willow flycatcher, the desert bald eagle, the Mexican spotted owl, the Yuma clapper rail and the yellow-billed cuckoo.

In fact, the stream abounds in endangered and threatened species. “Eighty-three special status species are present or potentially present within the Fossil Creek drainage,” the report concluded.

The creek also unrolls a welcome mat for an array of mammals, mile after mile. River otters and beavers both occur in the Fossil corridor. So potentially do rare mammals like red bats, Allen’s lappet-browed bat, spotted bats, greater Western mastiff bats and pale Townsend’s big-eared bats.

The challenge lies in balancing the economic benefits of drawing people to Fossil Creek against the unique refuge it has become for fish and wildlife, with an estimated 90,000 people visiting the creek annually.

But advocates for wildlife say that people have lots of places to swim and enjoy the outdoors, but Fossil Creek has become a species-saving ark for many southwestern fish, birds, mammals, reptiles, insects and amphibians.

“Fossil Creek is the only intact perennial system with continuous flow without any water diversions anywhere in Arizona,” the assessment report concluded. “Fossil Creek provides the only uninterrupted system between the Verde and the Mogollon Rim.”

RARE AQUATIC SPECIES

Headwater chub

Roundtail chub

Speckled dace

Longfin dace

Sonora sucker

Desert sucker

Spikedace

Loach minnow

Gila topminnow

Razorback sucker

Colorado pikeminnow

Fossil springsnail

Mayfly

California floater

OTHER RARE SPECIES

Merriam’s shrew

Western red bat

Spotted bat

Allen’s lappet-browed bat

Pale Townsend’s big-eared bat

Greater western mastiff bat

Plains harvest mouse

Bald eagle

American peregrine falcon

Common black-hawk

Northern goshawk

Abert’s towhee

Narrow-headed garter-snake

Lowland leopard frog

Northern leopard frog

Arizona toad

Reticulated Gila monster

Nikomis fritillary butterfly

Nitocris fritillary

Four spotted skipperling

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