# River-Wide Habitat Availability for Fish Habitat Guilds: Implications for In-Stream Flow Protection
## 3 Results  
We deployed 214 PAE grids to sample the Niobrara River fish community. The number of PAE grids used per study site (i.e., the number of HMUs sampled) ranged from 13 to 24 with an average of 17 PAE grids per study site. We collected 3345 fish representing 30 species and eight families. The results of multiple logistic regression calculations are presented in Table 2. Area under ROC curve values ranged from 54% to 86%. The habitat suitability model for the lobate margin guild used fish and habitat data from 24 PAE grids where lobate margin species were captured and nine PAE grids with high abundance of these species. The presence model for the lobate margin guild consisted of a number of habitat attributes that described HMUs with moderate velocities (15-30 cm s\({}^{-1}\)) and depths >125 cm. The abundance model for the lobate margin guild suggested an affinity for slightly greater water velocities (75-90 cm s\({}^{-1}\)). The habitat suitability model for the run guild used fish and habitat data from 69 PAE grids where run species were captured and 27 PAE grids with high abundance of these species. The presence model for the run guild consisted of a number of habitat attributes that described shallow HMUs with eroded banks and woody debris. The abundance model for the run guild suggested an affinity to higher velocities up to 90 cm s\({}^{-1}\) and gigalithal (i.e., bedrock) substrates. The habitat suitability model for the riffle guild used fish and habitat data from 124 PAE grids where riffle species were captured and 51 PAE grids with high abundance of these species. The presence model for the riffle guild consisted of a number of habitat attributes that described rocky substrates and moderately deep (50-75 cm) HMUs, but a negative response to main lobes. The abundance model for the riffle guild suggested an affinity to moderate velocities (30-45 cm s\({}^{-1}\)). The habitat suitability model for the slackwater guild used fish and habitat data from 85 PAE grids where slackwater species were captured and 34 PAE grids with high abundance of these species. The presence model for the slackwater guild suggested gravel substrates and a range of depths were important characteristics for the slackwater guild to be present at a HMU. The abundance model for the slackwater guild suggested an affinity for shallow depths and an aversion for run HMUs. The habitat suitability models for the habitat generalist guild used fish and habitat data from 13 PAE grids where habitat generalist species were captured and six PAE grids with high abundance of this species. The presence model for the habitat generalist guild consisted of a number of habitat attributes that described an aversion for deep (>125 cm) areas with moderately high velocities (45-60 cm s\({}^{-1}\)). The abundance model for the habitat generalist guild suggested an affinity to moderately deep areas and avoidance of moderately high velocities. The frequency of HMUs considered non-suitable, suitable, suitable, or optimal varied for fish guilds among river segments (Figure 2). The habitat rating curves suggested suitable habitat generally increased with increasing discharges across all fish habitat guilds and segments during the rearing and growth bioperiod (Figure 3). The lobate margin guild had the greatest amount of available habitat in segment 1 (Figure 3). Suitable habitat for the lobate margin guild was at 14% channel area (CA) for 0.1 cfsm, 28% CA at 0.2 cfsm, and 38% CA at 0.45 cfsm in segment 1. The riffle guild had the least amount of suitable CA in segment 1 never exceeding 5% CA. The lobate margin guild had the greatest amount of suitable channel area (49%) of any guild at the highest discharge in segment 2. The riffle guild had the least amount of suitable habitat available of any guild within segment 2 with a high of 7% CA at 0.37 cfsm. The lobate margin guild had the greatest amount of suitable CA at 0.16 cfsm (43%) in segment 3.