Date of Award
Robert Van Kirk
Determining habitat selection for an organism across a geographic distribution is a primary challenge in modern behavioral ecology. Quantifying habitat use becomes increasingly difficult for species that exhibit complex life histories and complementary habitat requirements. Rainbow trout are an archetypal example due to their tendency to form local populations across a diversity of environments. The Henry’s Fork of the Snake River provides an opportunity to utilize microhabitat selection models to quantify stream features that may drive adult rainbow trout behavior at the local scale. In particular, within an 8.5 km, low gradient, groundwater-dominated reach that exhibits a general lack of geomorphic features commonly associated with stream salmonids. During the summers of 2013 and 2014, available habitat was quantified and trout location was linked to environmental variables. Detailed habitat surveys indicate that macrophyte growth throughout the summer is a strong determinant of in-stream habitat at the reach and local scale and adds channel complexity. Microhabitat selection modeling showed adult rainbow trout prefer greater depths. Results also suggest that location response by trout is influenced by the amount of available macrophyte cover. Further research is needed to determine factors influencing aquatic plant growth in this system. Management strategies aimed at conservation of the study reach’s adult rainbow trout population should consider the influence of macrophyte abundance and species composition on habitat suitability.
Kuzniar, Zachary, "Adult Rainbow Trout Habitat Selection in the Henry’s Fork of the Snake River, Idaho" (2015). Masters Theses. 790.