Habitat Complexity and Stream Fishes Multi-Scale Assessment in Goose Creek (ID, UT, NV)

Dan Dauwalter and Kurt Fesenmyer, Trout Unlimited - Science

A collaborative project between Trout Unlimited and Idaho BLM

The Goose Creek subbasin in the Upper Snake River Basin has a diverse native fish assemblage that reflects the presence of rare non-game species and peripheral populations of Yellowstone Cutthroat Trout.

Rankings of Upper Snake River Basin subwatersheds based on native trout and non-game fish known or predicted distributions and watershed connectivity. See Goose Creek at bottom center.

This assessment examined linkages between native fishes and their habitat in the Goose Creek subbasin with several key findings: 1) fish diversity is linked to habitat diversity, and habitat diversity is linked to stream condition;2) various elements of habitat complexity are important to several native fishes at different spatial scales; and 3) land management focused on riparian and stream health is important in maintaining the habitat complexity important to fish community diversity and sensitive fish species that are rare in the Upper Snake River Basin.

Bluehead Sucker, Catostomus discobolus

Redside Shiner, Richardsonius balteatus

Northern Leatherside Chub, Lepidomeda copei

Yellowstone Cutthroat Trout, Oncorhynchus clarkii bouvieri

Using data from fish and habitat surveys throughout the Goose Creek watershed, we found that diversity in cover (e.g., large wood, undercut bank), substrates (e.g., boulders, gravel), water velocity, and water depths were all important in explaining diversity in the fish community across sample sites

Fish and habitat survey sites in the Goose Creek watershed. Catch-per-effort of Northern Leatherside Chub shown at sites where the species was collected
Electrofishing in Goose Creek (left) and measuring habitat in Goose Creek (right)
Partial regression plots showing a positive relation between four dimensions of habitat diversity (cover, substrate, flow, depth) and fish diversity across 41 sites in the Goose Creek watershed. There was a significant, positive influence each factor (P < 0.09)

The distribution of Northern Leatherside Chub in Goose Creek is influenced by streamflow complexity, and that streamflow complexity is typically higher when active or abandoned beaver dams are present. This suggests beaver reintroductions or beaver dam analogs should be evaluated as a stream restoration practice for Northern Leatherside Chub conservation in an adaptive management framework.

Northern Leatherside Chub often reside in sections of stream with complex streamflows, and complex streamflows are often associated with beaver dams
Path analysis was used to test linkages between different measures of streams habitat based on a conceptual model, and then show that Northern Leatherside Chub distribution was influence by streamflow complexity that was influence by beaver dams and stream pools. Chub were also found in streams with warmer temperatures.
Northern Leatherside Chub were collected below this old beaver dam in Trapper Creek

Northern Leatherside Chub also select microhabitats with overhead cover from mature woody and herbaceous riparian vegetation and streamflow complexity influenced by riffle-pool morphology, overhanging bank vegetation, and beaver dams. Maintaining riparian health standards should create Northern Leatherside Chub habitats used at small spatial scales to presumably benefit population dynamics that facilitate persistence

Pre-positioned areal electrofishing setup with a stainless steel braided wire loop anode and a Smith-Root LR-24 backpack electrofisher. Anodes were placed into the stream 15-20 minutes prior to fish sampling
Habitat selection probabilities of Northern Leatherside Chub for different microhabitat variables in Trapper Creek, Idaho. Top panels show use of overhead cover but only when water is deep (in pools). That is, there is an 'interacting' effect of overhead cover and water depth. Flow complexity (CV in velocity) also had a positive influence on habitat use
Biplot of PCA axes 1 versus 2. Left panel shows arrows for continuous habitat variables (scores multiplied by 4), centroids for wood and boulder cover (black) and beaver dams and woody shrubs (white). Right panel shows site scores with symbol size scaled by number of Northern Leatherside Chub collected (Gray =1 to 9 individuals; white = absent)

Yellowstone Cutthroat Trout abundance is limited by both Brook Trout and habitat complexity at the subspecies’ range periphery, and that Brook Trout negatively influences and instream cover diversity positively influences body condition of age-0 Cutthroat Trout. The negative interaction between Brook Trout and Cutthroat Trout early in life has been shown previously and emphasizes removal of Brook Trout as a cutthroat trout conservation action. However, this study also suggests that conserving or restoring habitat complexity should be more widely considered and evaluated as a complementary action that could promote coexistence of the two species

Yellowstone Cutthroat Trout sampled from Goose Creek on the Sawtooth National Forest
Sampling Goose Creek on the Sawtooth National Forest where Brook Trout and Cutthroat Trout occur in sympatry
Plots showing the density of Yellowstone Cutthroat Trout versus the density of Brook Trout less than 100 mm TL, greater than 100 mm TL, and all size classes. Yellowstone Cutthroat Trout were never abundant when sympatric with Brook Trout
Boxplots of relative condition (Kn) of Yellowstone Cutthroat Trout at sites with Brook Trout present versus Brook Trout absent. Age-0 Cutthroat Trout are in poorer condition when Brook Trout are present
Model selection statistics for plausible (∆AICc < 4) candidate linear regression models predicting relative condition (Kn) of age-0 Cutthroat Trout as a function of physical habitat variables and age-0 Brook Trout density (log(#/100 m2 )). Cover diversity is in a majority of plausible models, which shows its positive influence on age-0 Cutthroat Trout and that habitat diversity may facilitate co-existence between the two species

Land management is important in maintaining stream habitat diversity that plays a key role in maintaining fish diversity and and species of concern, the Northern Leatherside Chub and the Yellowstone Cutthroat Trout

Managed livestock grazing can help maintain stream habitat complexity and diversity. Bottom photo shows water gap in riparian exclosure on Little Birch Creek, a tributary to Goose Creek in Idaho
Little Birch Creek, Cassia County, Idaho
Lower Trout Creek, Elko County, Nevada