Wildfire webs link structure and function in Pacific Northwest forested watersheds
On this page:
Aquatic ecosystem resilience to wildfire can vary widely depending on the characteristics of fire and the spatial context of where a fire takes place. Researchers at EPA’s Office of Research and Development are collaborating with the US Forest Service, and Oregon State University to understand the drivers of aquatic ecosystem resilience to wildfires. In this presentation, we present an overview of four research projects addressing this theme and take a deeper look at one of them - a food web simulation model. In the model we varied riparian forest and instream physical channel dimensions to represent different spatial contexts that may contribute spatial heterogeneity to aquatic ecosystem responses to fire including different positions along a river continuum (headwater vs. floodplain), and the unique thermal and flow regimes associated with different ecoregions within the Pacific Northwest (westside vs. eastside forests). Model simulations compared unburned conditions to burned conditions across multiple fire severities (low, moderate, and high), and were run for 40 years to capture initial post-fire effects as well as longer-term responses to fire. Collectively these model simulations illustrate that fire effects on aquatic ecosystems are likely to vary widely according to sources of spatial heterogeneity associated with both exposure (fire characteristics) and inherent vulnerability (e.g., geomorphology, hydrologic and thermal regime). These results highlight the importance of taking spatial context into account when considering the potential implications of wildfire for fish. Such insights can inform broader regional spatial assessments of wildfire effects on fish and aquatic ecosystems.