Geomorphic Influences on the Distribution of Yellowstone Cutthroat Trout in the Absaroka Mountains, Wyoming

Abstract

Influences of large-scale abiotic, geomorphic characteristics on distributions of Yellowstone cutthroat trout Oncorhynchus clarki bouvieri arc poorly understood. We sampled 151 sites on 56 perennial streams in the Greybull-Wood river drainage in northwestern Wyoming to determine the effects of geomorphic variables on Yellowslone cutthroat trout distributions. Channel slope, elevation, stream size, and barriers to upstream movement significantly influenced the presence and absence of Yellowstone cutthroat trout. Wild populations of Yellowstone cutthroat trout were not found upstream of barriers to fish migration, at sites with channel slopes of 10% or greater, or at elevations above 3,182 m. Based on channel slope alone, logistic regression models correctly classified presence or absence of Yellowstone cutthroat trout in 83% of study sites. The addition of elevation and stream size in the models increased classification to 87%. Logistic models tested on an independent data set had agreement rates as high as 91% between actual and predicted fish presence. Large-scale geomorphic variables influence Yellowstone cutthroat trout distributions, and logistic functions can predict these distributions with a high degree of accuracy.

Influence of riffle characteristics, surficial geology, and natural barriers on the distribution of the channel darter, Percina copelandi, in the Lake Ontario basin

“…The upstream distribution limits of P. copelandi within the four rivers corresponded with impassable waterfalls. Natural barriers have a strong influence on the upstream distributions of fish species (Kruse et al 1997, Hicks 2003. At a larger scale, limited postglacial dispersal by North American fish species from glacial refugia has been linked to the presence of impassable waterfalls along Canadian rivers and Great Lakes tributaries (Bailey & Smith 1981, Rempel & Smith 1998.…”

Local‐Habitat, Watershed, and Biotic Features Associated with Bull Trout Occurrence in Montana Streams

“…All three of these habitat features have been identified as important predictor variables for the occurrence of bull trout (Rieman and McIntyre 1995;Watson and Hillman 1997;) and other salmonids (Bozek and Hubert 1992;Kruse et al 1997;Harig and Fausch 2002). The mechanisms underlying these patterns are uncertain, although differences in habitat composition, disturbance regime, and patch size may be involved (Bozek and Hubert 1992;Rieman and McIntyre 1995;Harig and Fausch 2002).…”

“…Watershed-scale habitat features.-Watershedscale features such as basin area, indices of disturbance, elevation, stream size, and channel slope have been used to predict the distribution of salmonids (Bozek and Hubert 1992;Rieman and McIntyre 1995;Kruse et al 1997;Paul and Post 2001;Pess et al 2002). We selected watershed variables that described some of the main influences on stream ecology that were readily measured from topographic maps.…”

Effects of riffle length on the short-term movement of fishes among stream pools

“…Additionally, knowledge of fish movement patterns can be useful in predicting the effects of physical barriers, which in streams exist in many forms. For example, persis-tent barriers such as waterfalls and debris dams can block migratory movements of fish, limiting access to stream reaches (e.g., Kruse et al 1997) or restricting gene flow between populations (e.g., Congdon 1995;Fausch and Young 1995). In intermittent streams, dry riffle habitats create temporary barriers to interhabitat movement that can affect species richness and incidence patterns within isolated pool habitats (e.g., Taylor 1997).…”