WSP04463

• File Number: 8460.500
• Description: Platte River Recovery Plan
• Basin: South Platte
• Date: 6/1/1997
• Author: Colo Div of Wildlife
• Title: Inventory and Status of South Platte River Native Fishes in Colorado
• Water Supply Pro - Doc Type: Publication

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There was no statistical reason to assume one method was superior to another. The choice of a
particular cluster analysis technique over another was purely a subjective decision based on the
biological knowledge of each species and whether the groupings made sense from a biological and
management standpoint. We further assumed that this methodology would be used as a starting
point only and that we would revise the groupings based on new species-habitat information.

A number of physical habitat parameters (Table I) were then regressed against species
occurrence to determine which appeared to influence presence the most. The procedure used was
forward selection step-wise logistic regression at the 0.15 significance level. Only species which
were found at 30 or more sites were considered in the logistic regression analyses.

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Table I. Water aua It v an I phvslca abltat parameters measure at eac sample sIte.
Chloride Backwater %
pH Riparian-tree cover %
Sulfate Riparian-grass %
Hardness Riparian-shrub %
Dissolved oxygen Silt %
Ammonia Sand %
PHTH alkalinity Gravel %
Total alkalinity Cobble %
Temperature Boulder %
Width (average) Total streambed veg. cover %
Depth (average) Total veg.- % algae
Velocity (ft/sec) Total veg.- % rooted material
Riffle % Riffle/pool ratio
Run % Undercut banks %
Pool % Gradient

RESULTS AND DISCUSSION

There are 18 hydrographic units (hydrounits) contained wholly or partially within the
South Platte River Basin in Colorado (Figure I). Fish sampling results are reported for each

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