UW Aquatic & Fishery Sciences Quantitative Seminar

Elliot Koontz

Quantitative Ecology and Resource Management, UW

Effect of wildfires on stream thermal regimes and implications for freshwater fish across the Pacific Northwest

Abstract

As climate change and a history of fire suppression continue to spur more frequent and severe wildfires in the Pacific Northwest, we face an increased need to understand the ecological ramifications of these disturbance events in freshwater ecosystems. The thermal regimes of streams and resident fish communities are believed to be sensitive to such disturbances, yet our current understanding of their impacts are limited to individual watersheds or burn events, and the environmental conditions driving variation in thermal response to wildfires have not been identified. In this talk, I will discuss the results of my first chapter quantifying the impact of wildfires on stream thermal regimes in the Pacific Northwest, and the implications for freshwater fish of varying thermal guilds and management concern. I will explain the spatial and temporal structure of my data, and present results illustrating the response in various thermal regime metrics following wildfires using a descriptive effect size analysis. Additionally, I will present the preliminary results of a redundancy analysis (RDA) describing the variation within a suite of thermal regime metrics to environmental conditions such as hydrology, fire severity and elevation. I will conclude with discussing the application of this research to inform wildfire and stream management, and further directions of research in analyzing the influence of wildfires in freshwater systems.