New Research Highlights Seasonal Changes in the Bighorn River's Food Web
- 3 hours ago
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Recently, a graduate student with Montana State University completed a research project analyzing five years of Bighorn River Alliance macroinvertebrate data collected from 2020–2024 in search of insights into how seasons and flow conditions impact the river's aquatic food web. Macroinvertebrates—aquatic insects, crustaceans, worms, and other small organisms that live on the river bottom, are an important food source for trout and are widely used as indicators of river health as they vary in their sensitivity and response to differing conditions.
The study found that the Bighorn's macroinvertebrate community follows consistent seasonal patterns, with a greater number of species detected in fall than in the spring and different species dominating each season. The research also documented a significant shift in the river's insect community following the unusually high flows of 2023, when the Bighorn experienced one of the largest runoff events in recent history.
While the overall macroinvertebrate community remained diverse, the composition of species changed noticeably after the 2023 high-water event, with the upper river marked by an increase in aquatic sowbugs. These findings suggest that large flow events can influence the river's food web and habitat conditions for several years following a flood.
Most importantly, the study demonstrates the value of BHRA's long-term monitoring program. Without consistent data collection over multiple years, these changes would have gone undocumented. As we continue to build one of the most comprehensive long-term datasets on the Bighorn River, this information will help improve our understanding of how flow conditions, habitat, and river management influence the health and resilience of the fishery.
We congratulate Katie Jeno on completing this important research and thank her for helping advance our understanding of the Bighorn River.
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