WSP12135

• File Number: 8210.766
• Description: Gunnison River General Publications - Correspondence - Reports - Etc
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 1/1/1996
• Title: Key Documents - Regulated Rivers - Research and Management - Volume 12 - 391-413 - A General Protocol for Restoration of Regulated Rivers
• Water Supply Pro - Doc Type: Report/Study

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RESTORATION OF REGULATED RIVERS

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economically important, non-native salmonid and other fisheries have been established from cultured stocks
in river segments world-wide, in almost every case this practice has failed miserably to meet its objective of
replacing lost fisheries (Lichatowich, in press), Stocking of native and non-native fish has irresponsibly
compromised native food-webs around the world and is rightfully called the Frankenstein Effect (Moyle
er al., 1986), A large body of literature debates this problem; the bottom line is that culture operations should
be avoided unless native biota are clearly headed for extinction as a consequence of habitat loss (Minckley
and Deacon, /991; Hilborn, 1992). Even then, cultured stocks cannot be expected to re-establish if they are
simply released back into the same degraded habitats. Ecological bottlenecks that compromised endangered
species in the first place have to be rectified, and the only way to do that in large river systems is to restore
habitat in a continuum context.

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Be wary of maPlagement actions chac atrempc Co control riverine fDod webs
Perhaps the greatest uncertainty in reregulating river systems to restore hot spot connectivity (Figure 2) is
the unexpected consequence of the inexorable proliferation of non-native biota, Wendell Minckley and
James Deacon, the sages of fish ecology in the species-rich American Southwest often rightly noted that
locally adapted fish of the desert are clearly able to deal with extreme environmental variation, but natives
are quickly depressed or driven to extinction by food-web change associated with invasions of non-native
species (e,g. Minckley and Douglas, 1991), However, restoration of natural lIow and temperature
dynamics compromises the ability of non-native species to sustain viable populations and promotes
native species (Li er ai" 1987; Meffe and Minckley, 1987; Bain er ai" 1988), Even with restoration of
the full range of natura I II ow variation, interactions with non-native plants and animals will most likely
continue to be a problem for native biodiversity management and conservation.
One alternative is to control non-native populations by aggressive harvest. However, it is very difficult to
do this without also affecting natives, and prediction of the inlluence of the food-web structure is tenuous at
besL Moreover, in some cases one or a few native species have become very abundant in regulated rivers
along with non-natives, For example, native squawfish (Prychocheilus oregonensis) in the Columbia River,
USA, are thought to be a major source of predation mortality for juvenile salmon, which exist in very depressed
populations (Poe er al., \99\; Rieman er ai" \99\) and a very aggressive control programme has been initiated
by paying fishermen a bounty for each squawfish caught. However, food-web structure in the lower Columbia
River is poorly known, a wide variety of non-native predators are present and predicting food-web responses as
well as influences on salmon mortality is tenuous, A congener (P,lucius) in the Colorado River is listed as endan-
gered and a very expensive recovery program has been initiated, For many people these strategies seem at cross-
purposes, even though the ecology of the two species is very different.
In general, the effectiveness of predator control programmes is minimal or poorly demonstrated even
. though it is a very popular management strategy. We agree with Goodrich and Buskirk (1995) that popula-
tion control of abundant native vertebrates should be a strategy of last resort for conservation of rare
natives, Columbia River salmon evolved with squawfish predation and restoration of proper habitats for
salmon smolts clearly should reduce smolt mortality. However, constraining proliferation of non-native
plants and animals is an obvious need for conservation of native biodiversity,
Again, the preferred approach may be to implement reregulation to restore lost habitat and allow the
food-web to adjust as it will. The available body of information suggests that natives will fare better than
non-natives, Clearly, it is advisable to document and monitor food-web dynamics carefully from a commu-
nity ecology perspective.

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Use adaptive ecosystem management

Any strategy to remediate the effects of large river regulation will require an adaptive approach, Scientists
can be relied upon to document ecological problems by research and synthesis of empirical information on
cause and effect, but the solution of problems must involve knowledge of human perceptions and desires,
which are often different from that inferred by the strict interpretation of the science (Ludwig el aI.,
1993), In most cases, inefficient information transfer between science, management, policy makers (govern-
ment) and the general public hinders the attainment of common ground.

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