Patterns in Fish Assemblage Structure in a Small Western Stream
Knowledge of how patterns in fish assemblages are spatially structured is important for guiding management and conservation actions. However, most studies have taken place in the eastern and midwestern U.S., resulting in a poor understanding of factors influencing western stream fishes. The objectives of this study were to evaluate habitat and species associations of fishes in Deep Creek, a small tributary of the Kootenai River in Idaho. Fishes and habitat were sampled from 58 reaches in Deep Creek. In total, 7,129 individual fishes representing 18 species were sampled. Patterns in species richness were largely a function of channel gradient and associated habitat characteristics. Species richness decreased with increased channel gradient. Species-specific habitat relationships for native and nonnative fishes in Deep Creek provided specific insights into the ecology of each species. Predicted probability of occurrence and relative abundance varied by species and were related to a broad suite of environmental characteristics. This study provides insight on patterns of fish assemblage structure, as well as important information on the ecology of native and nonnative fishes in a western stream system.
Deep Creek watershed showing the main channel of Deep Creek, Deep Creek's five major tributaries (i.e., Trail, Fall, Ruby, Brown, and Snow creeks), and the Idaho portion of the Kootenai River. Circles represent the 58 stream reaches sampled on Deep Creek. Upper, middle, and lower sections of Deep Creek are also shown.
Total number of individuals of each species sampled from Deep Creek and each individual section (i.e., upper, middle, and lower) during the summers of 2014 and 2015. Taxa include Brown Bullhead (BBH), Burbot (BBT), Brook Trout (BKT), Black Crappie (BLC), Bluegill (BLG), Lake Chub (LKC), Largemouth Bass (LMB), Longnose Dace (LND), Largescale Sucker (LSS), Mountain Whitefish (MWF), Northern Pikeminnow (NPM), Peamouth (PEA), Pumpkinseed (PKS), Rainbow Trout (RBT), Redside Shiner (RSS), Tench (TEN), Torrent Sculpin (TSC), and Yellow Perch (YEP).
A stream elevation (m) profile of Deep Creek from the McArthur Lake impoundment to its confluence with the Kootenai River (river kilometer 0). Vertical bars represent the breaks between the lower, middle, and upper sections of Deep Creek. Circles represent the species richness value for each of the 58 sampled reaches in Deep Creek.
Non-metric multidimensional scaling ordination (stress = 13.8) of reach-specific (n = 58) fish assemblage presence-absence data from Deep Creek organized by section (upper, middle, lower). Species scores are displayed in the middle figure, and taxa include Brown Bullhead (BBH), Burbot (BBT), Brook Trout (BKT), Black Crappie (BLC), Bluegill (BLG), Lake Chub (LKC), Largemouth Bass (LMB), Longnose Dace (LND), Largescale Sucker (LSS), Mountain Whitefish (MWF), Northern Pikeminnow (NPM), Peamouth (PEA), Pumpkinseed (PKS), Rainbow Trout (RBT), Redside Shiner (RSS), Tench (TEN), Torrent Sculpin (TSC), and Yellow Perch (YEP). Significant (P < 0.002) habitat vectors were fit to the ordination and include the proportion of coarse substrate, mean depth, the proportion of instream woody cover, and the proportion of instream vegetative cover. The closer species or reach scores are located to one another on the ordination, the more closely the presence of those species and (or) reaches are associated with one another. Habitat vectors are in the direction of the increasing values of the habitat variable.
Non-metric multidimensional scaling ordination (stress = 13.8) of reach-specific (n = 58) fish assemblage relative abundance data from Deep Creek organized by section (upper, middle, lower). Species scores are displayed in the middle figure, and taxa include Brown Bullhead (BBH), Burbot (BBT), Brook Trout (BKT), Black Crappie (BLC), Bluegill (BLG), Lake Chub (LKC), Largemouth Bass (LMB), Longnose Dace (LND), Largescale Sucker (LSS), Mountain Whitefish (MWF), Northern Pikeminnow (NPM), Peamouth (PEA), Pumpkinseed (PKS), Rainbow Trout (RBT), Redside Shiner (RSS), Tench (TEN), Torrent Sculpin (TSC), and Yellow Perch (YEP). Significant (P < 0.002) habitat vectors were fit to the ordination and include the proportion of coarse substrate, mean current velocity, mean depth, and the proportion of instream vegetative cover. The closer species or reach scores are located to one another on the ordination, the more closely the relative abundance of those species and (or) reaches are associated with one another. Habitat vectors point in the direction of the increasing gradient of the habitat variable (e.g., increasing mean water velocity) on the ordination.
Contributor Notes
Associate Editor: M. P. Davis.