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Fire effects on herbaceous regeneration across an invasion gradient in grasslands and shrublands

September, 2017 to May, 2021

Fire crews light a burn box on a grassy plain in South Dakota
Buffalo Gap National Grassland Fire Crew lights a burn box in the fall in western South Dakota. The fire is controlled using the burn box and a wet line. (credit Lily Huffman)
Grazing, fire, and climate are the primary drivers that have historically shaped and continue to shape our grasslands. In perennial grasslands, most grass and forb stems you see come from below-ground buds and not from seed. Fire effects on the regeneration potential (i.e. buds and meristems) of the native herbaceous plant community in northern mixed-grass prairie and eastern sagebrush steppe are poorly understood but critical for appropriate management and the conservation of biodiversity and ecosystem function. Our primary objectives are to:

  1. Determine the regeneration potential of important/desirable forbs and grasses from belowground buds following fire,
  2. Determine how pre-fire community composition affects post-fire regeneration, especially focusing on the effect of exotic annual brome abundance,
  3. Investigate the effect of fuel loading on the regeneration resiliency of grasslands and shrublands,
  4. Examine how post-fire drought impacts grassland resiliency,
  5. Determine the response of big sagebrush (Artemisia tridentata) to low intensity fire.

Our combined laboratory and field approach will provide basic and applied understanding of plant responses to fire that can be used to make management decisions regarding the role of prescribed fire in maintaining adequate forage for livestock and appropriate habitat for Greater Sage-grouse (Centrocercus urophasianus)

Dr. Jacqueline Ott places thermocouples and flux meters in the plot to measure soil and litter temperatures during the fire.
Dr. Jacqueline Ott places thermocouples and flux meters in the plot to measure soil and litter temperatures during the fire. (credit Lily Huffman)
A fire crew creates a wetline around a burn box to help keep a fire controlled.
Buffalo Gap National Grassland Fire Crew places a wetline around the burn box before lighting it. (credit Lily Huffman)
while also preventing invasion by non-native plant species. This research will provide needed information on the post-fire regenerative ability of key forb species and their genera that are important for wildlife, especially pollinators and the Greater Sage-grouse. We will also deliver needed results on how annual brome invasion impacts the resiliency and regeneration of grasslands and shrublands in the northern Great Plains before brome invasion reaches levels comparable to those of the Intermountain West.

Most studies look at the aboveground response to fire and document production changes or species changes. This research aims to gain a better understanding of the underlying mechanisms driving those changes, such as the role of the bud bank, changes in nutrient availability, and changes in response to post-fire drought. By linking pattern (what happened) with process (why it happened), researchers and managers will be able to better predict what will happen in future scenarios.

For additional information, please see Fire and bud sprouts: New study looks at how fire affects plants on our national grasslands



A completed plot burn shows a small burned area in the shape of burn box.
Completed plot fall burn on Buffalo Gap National Grassland. (credit Lily Huffman)
This research is divided into two parts.

Part A focuses on the impact of fire fuel loads on 8 key forb species and their neighboring dominant grass species. Cores (12-inch diameter) will be harvested from mixed-grass prairie and shortgrass steppe locations. A focal species will be located at the center of each core. Using a fire table, cores will be burned off at various fuel loads and soil temperatures will be monitored during fire. Post-fire regeneration of the focal and associated species under well-watered and drought conditions will be evaluated. Cores will be harvested and burned during a variety of seasons. This methodology enables us to examine fire effects on species that are common but not abundant enough in the field to capture in small-scale field fires.

Part B focuses on the impact of fire on survival, vegetative reproduction, and seedling recruitment of grassland and shrubland plant populations and communities across an invasion gradient of annual bromes. Fire effects on shrubs, and specifically Artemisia tridentata, will also be examined. Using burn

An example of a fire table that is used to burn cores is shown along with an unburned core.
Fire table used to burn cores. The core is placed in the hole at the end of the fire table. The fire is lit from one end of the fire table and then runs into the core. (credit Brian Dickerson)
Dr. Jacqueline Ott places thermocouples to measure bud and soil temperatures on the core during a fire table experiment.
Dr. Jacqueline Ott places thermocouples to measure bud and soil temperatures on the core during a fire table experiment. (credit Brian Dickerson)
boxes, multiple 2m x 4m plots will be burned in mixed-grass and shortgrass steppe in either the fall or spring. These plots will occur across a range of annual brome abundance. Some plots will have a rainout shelter placed over them following fire to simulate post-fire drought. Forage quality, production, species composition, nutrient availability, and bud bank density are some of the variables that will be measured. Part B research will enable us to understand the role of regeneration at the community level and provide context for the post-fire regeneration of key species examined in Part A.


Expected deliverables:

  • Conference presentations
  • Field Days in 2020 in South Dakota and Wyoming after results are analyzed
  • Webinar at the end of the study
  • Refereed publications

Project Contact: 

Principal Investigators:
Troy Ocheltree - Colorado State University
Lauren Porensky - USDA Agricultural Research Service
Derek Scasta - University of Wyoming
Amy Symstad - USGS Northern Prairie Wildlife Research Center

Buffalo Gap National Grassland
Thunder Basin National Grassland
Thunder Basin Grassland Prairie Ecosystem Association

Research Staff:
Funding Contributors:
Joint Fire Science Program