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Project ID:

08-1-5-19

Year:

2008

Date Started:

05/01/2008

Date Completed:

07/02/2012

Title:

Cumulative Effects of Fire and Fuels Management on Stream Water Quality and Ecosystem Dynamics

Project Proposal Abstract:

Prescribed fires and wildland fire-use are increasingly important management tools used to reduce fuel loads and restore the ecological integrity of western forests. Although a basic understanding of the effects of fire on aquatic ecosystems exists, the cumulative and possibly synergistic effects of wildfire following prescribed fire are unknown. Wildfires following prescribed fire will likely produce different burn severities and effects on riparian and stream ecosystems than wildfires in fire suppressed forests (e.g., fires absent >70 yrs) or prescribed fires alone. Given the potential for these various burn scenarios to affect water quality, habitat conditions for sensitive species, and costs associated with post-fire rehabilitation, information that can help characterize the effects of different burn scenarios are critically needed. The goal of this study is to quantify and compare the effects of wildland fire on stream ecosystem responses under three fire management practices: (1) wildfire following prescribed fire, (2) wildfire in fire suppressed forests, and (3) wildfire occurring at historic fire return intervals. We are in a unique position to make these comparisons because of seven years of existing pre-fire data (2001-2007) on stream biota and habitat on tributaries of the South Fork Salmon River and Big Creek watersheds in central Idaho. In August and September 2007, two large wildland fires (Cascade Complex and East-Zone Complex) burned across 10 of our study streams. This created a rare opportunity to examine post-fire water quality, stream community, and riparian forest responses to wildfire in streams flowing through watersheds that had been previously burned in a prescribed fire (5 streams) and streams flowing through fire suppressed forests (8 streams). Abiotic and biotic trends in these 13 streams will be compared to 7 streams flowing through an adjacent wilderness area that burned one or more times in the last 20 years under a fairly natural fire regime and which we have sampled annually since 2001. Because stream and riparian communities are inherently dynamic, availability of pre-fire data allows for robust analyses capable of differentiating fire effects from natural variability. In all watersheds, we will resample the same metrics as previously (2001-2007) sampled: riparian- and watershed-level burn severity patterns, riparian forest structure, hydrology, amphibians, aquatic macroinvertebrates, periphyton, and instream habitat (temperature, chemistry, substrate, sedimentation, and large woody debris). The proposed three years of post-fire sampling will allow us to conduct a before-after-control-impact (BACI) analysis providing greater statistical power and inference for possible cause-effect relationships.
The proposed research directly addresses RFA Task 5; the re-measurement of recently burned-over experimental sites where extensive pre-fire data are available on fuel treatments, pre-fire riparian stand structure, and stream habitat and biota. Since fire behavior observations exist and we plan to use satellite imagery to quantify dNBR, we will evaluate the effects of pre-fire conditions on fire severity and resource impacts. The results of this study will provide critical information necessary for managers to (1) evaluate the immediate and long-term effects of alternative fire management activities on stream ecosystems, (2) assess how fire management affects the ecological integrity of aquatic communities, and (3) identify potential opportunities to better manage habitats and food webs supporting Threatened and Endangered aquatic species.

Principal Investigator:

David S. Pilliod

Agency/Organization:

USGS-Geological Survey

Branch or Dept:

BRD-Snake River Field Station

Other Project Collaborators

Type	Name	Agency/Organization	Branch or Dept
Co-Principal Investigator	Clifford R. Bossong	USGS-Geological Survey	BRD-Water Science Center-CO
Co-Principal Investigator	Robert S. Arkle	USGS-Geological Survey	BRD-Snake River Field Station
Federal Cooperator	David S. Pilliod	USGS-Geological Survey	BRD-Snake River Field Station

Project Locations

Fire Science Exchange Network

Northern Rockies

Northwest

Level	State	Agency	Unit
STATE	ID	BLM	Challis Field Office
STATE	ID	BLM	Salmon Field Office
STATE	ID	FS	Challis National Forest
STATE	ID	FS	Salmon National Forest