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Project ID: 13-1-06-13


Date Started: 08/01/2013

Ending Date:  12/31/2016

Title: Using Cheatgrass Suppressive Soil Bacteria to Break the Fire Cycle and Proactively Maintain Greater Sage-Grouse Habitats

Project Proposal Abstract: Northwest rangeland fires of 2012 highlight the urgent need to break the annual grass/fire cycle in sagebrush communities. Management practices that increase understory cover as needed by nesting and brood-rearing grouse also have the potential to increase fire risk due to horizontal continuity of fuels if annual grasses are present. Techniques are needed that can interrupt continuous fine fuel loads while minimizing disturbances that would weaken or remove habitat features required by sage-grouse. Reducing cheatgrass cover reduces flame length and rate of spread and lowers fire risk. Application of the cheatgrass suppressive soil bacteria, Pseudomonas fluorescens (P.f.), to the soil of sagebrush communities can reduce the canopy cover of cheatgrass through suppression of root growth, tiller formation, and seed bank. While this technology has been field tested at scales of less than one acre, methods that are applicable for landscape-scale application are needed and newer more effective strains of the bacteria such as P.F. ACK55 should be used in these tests. The objectives of this project are to a) evaluate the efficacy of P.f. ACK55 as a fine-fuel reduction tool for Wyoming big sagebrush plant communities that are important sage-grouse habitat, b) Develop an effective bacterial delivery system that will enhance large-scale application of the bacteria and increase bacterial survival to impact altered fire regimes and sage-grouse home ranges, and c) Determine the environmental factors associated with successful establishment of the bacterium in the soil and efficacy of cheatgrass reduction. Our hypotheses are that  a) Sites successfully colonized by P.f. strain ACK55 will have reduced cover and seed germination of cheatgrass that increases with time compared to control plots, and b) A delivery method (pellets) that protects P.f. strain ACK55 from extreme temperatures and drought until fall rains will ensure bacterial survival and efficacy and allow application at landscape scales. We will apply P.f ACK55 in the fall of 2013 to one set of plots and again in the fall of 2014 on another set of plots adjacent to the first on two climatically distinct National Wildlife Refuges (Hart Mountain in Oregon (mesic), and Saddle Mountain in Washington (dry) near SageSTEP study sites. The pellets designed for use in aerial applications will be broadcast to the soil surface of 2-acre plots. Controls will consist of non-inoculated pellets and no treatment. Each site will have five replicates per treatment per year. We will evaluate cheatgrass density, cover, seedbank and fine fuel characteristics; and vegetation and soil microbial community response at the two locations for three years and beyond. Specialized techniques will be used to monitor and verify bacterial survival in the soil. The results of these experiments will provide critical information for the development of protocols that ensure successful establishment of the bacterium at landscape scales, providing land managers a tool for proactively maintaining remaining at risk Wyoming big sagebrush communities that are priority habitat for greater sage-grouse. The findings will be communicated via reports, peer-reviewed publication, webinar, and ongoing extension activities of the PI and co-PIs.

Principal Investigator: Michael A Gregg

Agency/Organization: FWS-Fish and Wildlife Service

Branch or Dept: Mid-Columbia River NWRC-Hanford Reach Nat'l Monument

Other Project Collaborators




Branch or Dept

Agreements Contact

Carla D. Quick

FWS-Fish and Wildlife Service

Mid-Columbia River NWRC-Hanford Reach Nat'l Monument

Budget Contact

Carla D. Quick

FWS-Fish and Wildlife Service

Mid-Columbia River NWRC-Hanford Reach Nat'l Monument

Co-Principal Investigator

Ann C. Kennedy

ARS-Agricultural Research Service

Land Management and Water Conservation Research

Co-Principal Investigator

David A. Pyke

USGS-Geological Survey

FRESC-Forest & Rangeland Ecosystem Science Center

Project Locations

Fire Science Exchange Network

Great Basin


Southern Rockies







Project Deliverables

There is no final report available for this project.
There are no deliverables available for this project.

Supporting Documents

There are no supporting documents available for this project.

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