Presenter Information

Cody Bish, University of Wyoming

Department

Wyoming Natural Diversity Database

First Advisor

Lusha Tronstad

Description

Wildfire severity is predicted to increase with global climate change. Wildfire may affect stream fisheries by altering their main food source, aquatic invertebrates. We were able to investigate how the density and diversity of aquatic invertebrates changed after wildfire, because a wildfire unexpectedly started after collecting samples for 1 year. Therefore, we collected invertebrates one summer before the wildfire, and two summers after the wildfire. We used a Hess sampler to collect invertebrates every 2 to 4 weeks in Cub Creek, Yellowstone National Park. The samples were sorted, counted, measured, and identified under a dissecting microscope. The summer after the wildfire, invertebrate density (1150 ind/m2) was similar to pre fire density (900 ind/m2), but the second summer after the wildfire density increased 2.5x (2600 ind/m2). Invertebrate density may have been similar immediately after the fire due to flooding that occurred, because the lack of primary producers decreased water storage in the watershed. The second summer after the wildfire Plecoptera (2x), Diptera (4x) and Ephemeroptera (2.5x) densities increased. Despite an increase in density, invertebrate diversity was similar among years. More invertebrates may be available to fish to consume after wildfire.

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How wildfire affected aquatic invertebrates in Yellowstone National Park, Wyoming

Wildfire severity is predicted to increase with global climate change. Wildfire may affect stream fisheries by altering their main food source, aquatic invertebrates. We were able to investigate how the density and diversity of aquatic invertebrates changed after wildfire, because a wildfire unexpectedly started after collecting samples for 1 year. Therefore, we collected invertebrates one summer before the wildfire, and two summers after the wildfire. We used a Hess sampler to collect invertebrates every 2 to 4 weeks in Cub Creek, Yellowstone National Park. The samples were sorted, counted, measured, and identified under a dissecting microscope. The summer after the wildfire, invertebrate density (1150 ind/m2) was similar to pre fire density (900 ind/m2), but the second summer after the wildfire density increased 2.5x (2600 ind/m2). Invertebrate density may have been similar immediately after the fire due to flooding that occurred, because the lack of primary producers decreased water storage in the watershed. The second summer after the wildfire Plecoptera (2x), Diptera (4x) and Ephemeroptera (2.5x) densities increased. Despite an increase in density, invertebrate diversity was similar among years. More invertebrates may be available to fish to consume after wildfire.