Introduction to Wildfire and Aquatic Ecosytems

Why is it important to understand the effects of wildfire on our aquatic ecosystems?

Role of Wildfire

Wildfire disturbance plays an overriding natural role in the spatial and temporal structuring of vegetation and aquatic habits in Western North America.

Adaptation

Our ecosystems, both terrestrial and aquatic have evolved with wildfire and have adapted resilience to wildfire.

Suppression and Climate Change

A century of wildfire suppression combined with climate change have resulted in the increased frequency and severity of fires across the intermountain west.

Human Influence

Human occupation across the landscape especially in the wildland urban interface (WUI) has limited the potential for humans to allow fire to play its natural role.  Moreover, fire suppression activities themselves may introduce invasive species that may become established in terrestrial and aquatic ecosystems disturbed by wildfire.

Land Management

Forest Service land managers work together to take advantage of opportunities to let fire play its natural role on the landscape while protecting critical values at risk including life and property.  By understanding the short and long-term effects of wildfire on aquatic ecosystems, fisheries biologists are working with fuels and wildfire managers to make informed decisions when developing fuels reduction projects or managing wildfire incidents.  Forest Service scientists including fisheries biologists and hydrologists work as resource advisors to minimize the effect of fire suppression actions on aquatic resources.  These include but are not limited to hand and mechanized fire line construction and water conveyance and application activities.  Scientists also work on Burned Area Emergency Response teams to assess potential for indirect post-fire runoff effects to critical values at risk.  BAER Teams then direct resources to protect these values at risk.  Values at risk may include rare or threatened species or habitats, municipal drinking watersheds, critical infrastructure such as roads, bridges, or utility lines, or even private dwellings.  Forest Service scientists also work on interdisciplinary teams to help develop fuels reduction projects focused on reducing severity of future wildfires.  These specialists develop design criteria that protect aquatic resources such as lakes, rivers, and streams while meeting fuels management objectives.

Burned Stream Student Activity

Burned Stream Activity Videos

  • Burned Soil Simulated Rain Event

Video description: Results. Does not absorb any water. Water flows quickly over the top removing top soil as it goes. 

  • Seed and Mulch Demo

Video description: Post-fire rehabilitation. Grass seed and straw mulch effectiveness demonstration. Showing two different dirt sources on a waterflow table. Sources from left to right are Emigrant Peak Fire hydrophobic soil (high burn severity) and unburned soil. Results. Burned soil sheds the water and topsoil, whereas unburned soil absorbs most of the water. Another example is Bridger Foothills Fire soil (moderate-high burn severity). Adding seed and mulch to top of soil decreases soil run off.

  • Stream Model Full Simulation

Video description: Stop motion video of burned stream model simulation.

  • Stream Shading (No Sound)

Video description: Direct fire effects of stream shading. Here we are simulating stream shading on a stream channel between a burned watershed and an unburned watershed. You will see that we have some good shadows of these trees on the stream channel in order to provide shading of the stream. Now once the sun moves to the burned side of the drainage, you can see that there is not very much shading over the stream channel. These burned trees have lost their foliage so they really don’t provide much in the way of stream shading.

  • Stream Shading

Video description: Direct fire effects of stream shading. Here we are simulating stream shading on a stream channel between a burned watershed and an unburned watershed. You will see that we have some good shadows of these trees on the stream channel in order to provide shading of the stream. Now once the sun moves to the burned side of the drainage, you can see that there is not very much shading over the stream channel. These burned trees have lost their foliage so they really don’t provide much in the way of stream shading.

  • Unburned Soil (Background Music Only)

Video description: Unburned soil simulated rain event. Results. Water is absorved by soil, very little runoff. 

Additional Resources

Articles, Readings, and Presentations

Media