Effects of warming and drying on the survival and performance of giant salmonfly nymphs (Pteronarcys californica)

Author

Kailie Todd, University of Montana, MissoulaFollow

Graduation Year

2023

Graduation Month

May

Document Type

Thesis

Degree Name

Bachelor of Science

School or Department

Forestry and Conservation

Major

Wildlife Biology – Terrestrial

Faculty Mentor Department

Biological Sciences, Division of

Faculty Mentor

Art Wodds

Keywords

Madison River, Flow, Aquatic invertebrates

Subject Categories

Other Animal Sciences

Abstract

Rising temperatures and anthropogenic influences threaten to alter aquatic ecosystems as oxygen supply and demand is altered depending on temperature, flow, and water presence. In late November of 2021, a dam malfunction occurred on the Madison River in Montana that caused the river to dry rapidly downstream of the dam and reduced flow by 70% for 50 hours. My experiments were designed to determine the effects of this event by assessing how long giant salmonfly nymphs (Pteronarcys californica) can survive in still water and in air depending on temperature and relative humidity. In the laboratory, we exposed salmonfly nymphs to four temperatures (5, 12.5, 20, and 25 ℃) in still water. We measured survival, feeding, and growth, as well as time spent performing ‘push-ups’ – a common respiratory movement that ventilates gills and increases oxygen supply rates. My study demonstrates that increases in temperature significantly increase the rate of pushups performed and decrease the survival of salmonfly nymphs. Next, we exposed nymphs to air – representing extreme dewatering – at five temperatures (5, 12.5, 20, 25, and 35 ℃) and two relative humidities (75% and 100%) to measure their survival. Survival times declined at higher temperatures, particularly in lower humidity, with an average survival of less than a day. Notably, the most significant factor influencing salmonfly survival was the type of medium they were in, as most of the nymphs in still water were able to survive the duration of the two weeks, while all the nymphs in air died.

Honors College Research Project

No

GLI Capstone Project

no

Recommended Citation

Todd, Kailie, "Effects of warming and drying on the survival and performance of giant salmonfly nymphs (Pteronarcys californica)" (2023). Undergraduate Theses, Professional Papers, and Capstone Artifacts. 449.
https://scholarworks.umt.edu/utpp/449