7638

• UCREFRP Catalog Number: 7638
• Author: Stevens, L. E.
• Title: Ecological Characterization of the Wetlands of the Colorado Plateau.
• USFW Year: n.d.
• USFW - Doc Type: Flagstaff, Arizona.
• Copyright Material: NO

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including the Eagle, Blue, Crystal, Dolores, Slate, Yampa, Animas,
and Uncompahgre Rivers in Colorado. The effects of acid rain on
Colorado Plateau wetlands are also gaining recognition. Several
examples of these problems are provided below.

Acid rain. Acid precipitation has begun to have an effect on
high elevation ecosystems. Funk (1983) simulated acid
precipitation on two tundra plant species, Acomastylis rossii and
Bistorta vivipara, demonstrating significantly different effects
on growth and reproduction between these two species. He
concluded that lithe selective pressure on plant species by acid
precipitation could result in changes in communitr. structure and
successional patterns within the tundra ecosystem' (Funk 1983:iv).

Municipal pollutants. Hamann (1982) examined the persistence
of chlorine residuals from sewage in Gore Creek (a tributary of
Eagle River) and other Colorado streams. He found that chlorine
was the largest single source of toxicity in the three streams
studied, with effects ranging from elimination of fish and
invertebrates in some creeks for as much as 4 km, to a shift in
species composition in Gore Creek. Concentrations in Gore Creek
measured 0.08 mg/L, with factors contributing to persistence
including high initial concentrations, low dilution ratios, low
turbulence, low temperature and reduced sunlight penetration.
Chlorine tolerance varied between fish species, with reduced
growth of brook trout at 0.005 mg/L. Because removal of chlorine
residuals can be done cheaply, such measures could increase stream
community diversity and stability, thereby enhancing the fishery
and other recreational value of the stream.

Thermal pollution. Thermal regimes influence aquatic biota
in Colorado Plateau streams by limiting physiological activity and
reproductive behavior; however, relatively little research has
been published on thermal alterations in the Colorado River
drainage. Although thermal power plant cooling releases slightly
increased stream water temperatures in the Yampa River (Wentz and
Steele 1980), the impacts of such changes have not been
identified. Dam-induced thermal alteration of river water is
largely held responsible for the loss of native fish fauna in the
Green River below Flaming Gorge Dam, and in the Grand Canyon below
Glen Canyon Dam. Steele (1985) conducted an harmonic analysis of
daily water temperature data from major streams in the upper
Colorado River basin. He found that 80% of the annual variance in
water temperature at a given site could be accounted for by a
simple-harmonic (sine curve) function. Similarly, the Yampa
River's water temperature followed a harmonic sine function with
summer maxima and winter minima (Boyle et al. 1984). Thus, the
impacts of impoundment on downstream water temperature are often

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