Recipient Organization
MONTANA STATE UNIVERSITY
(N/A)
BOZEMAN,MT 59717
Performing Department
(N/A)
Non Technical Summary
Recent increases in the severity and frequency of extreme weather events (e.g., drought) are causing high-severity rangeland wildfires to occur more often than ever before. Ranchers and other rangeland managers are struggling to adapt. Past research and experience are less relevant today, and research-based information to guide post-fire management is limited because the unpredictability of wildfire makes it difficult to conduct well-designed studies that include pre-burn data. Currently, livestock grazing is commonly excluded from burned areas for 1 or 2 growing seasons post-fire. This practice is especially difficult for small and medium-sized ranches that often have few, if any, alternative areas for post-fire grazing, and increasing wildfire frequency exacerbates this problem. Fortunately, a growing body of literature indicates that rangeland plants recover from wildfire more quickly than previously thought. More research is needed to identify post-fire livestock grazing strategies that sustain rangeland vegetation. Much less is known about how rangeland soils respond to severe wildfires and post-fire livestock grazing. Given the increasing frequency of severe rangeland wildfires, there is a critical and immediate need to develop post-fire livestock grazing strategies that can sustain rangeland plant and soil health while also sustaining food and fiber production and the socioeconomic health of rural ranching communities. The research portion of our project centers around a wildfire that occurred on the USDA-ARS Livestock & Range Research Laboratory in Miles City, MT on September 20, 2022. The fire spread rapidly through areas where, fortuitously,vegetation and soil data had been collected prior to the fire during summer of 2022. Thus, we have an unparalleled opportunity to compare rangeland plant and soil health Before and After a high-intensity wildfire event. The 1,100-acre wildfire burned within a 7,563-acre rangeland pasture and yielded a gradient of fire severity across the pasture. We will apply cattle grazing at a moderate stocking rate in summer 2023 which will enable us to examine plant and soil response to the interactive effects of fire severity and cattle grazing intensity across the pasture. The Extension portion of our project includes ranchers; tribal, state and federal natural resource agency personnel;Extension educators;and research scientists collaborating together to formulate the research objectives and methods, analyze the data, and intrepet the research results. Our collaborative stakeholder group also will work together to 1) synthesize our research results into cattle grazing management guidelines, and 2) disseminate the project's findings to our target audiences.
Animal Health Component
100%
Research Effort Categories
Basic
0%
Applied
100%
Developmental
0%
Goals / Objectives
Major goals of the projectWe will investigate vegetation, soil, and cattle response during the first year after a late-summer wildfire. The major goal of the project is to determine whether cattle grazing during the first growing season after wildfire can sustain or enhance rangeland health.ResearchObjective A: Evaluate wildfire and livestock grazing effects on Northern Great Plains rangeland vegetation during the first year after a late-summer wildfire.Objective B: Evaluate wildfire and livestock grazing effects on Northern Great Plains rangeland soil during the first year after a late-summer wildfire.ExtensionObjective A: Use co-production science to integrate stakeholder knowedge and perspectives into the project's research objectives, methods, data analyses and interpretations, and educational products.Objective B: Develop and communicate new, post-wildfire cattle grazing guidelines.
Project Methods
Research MethodsAcross a gradient of wildfire severity, all sampling follows a Before-After-Control-Impact design (BACI) in which pre-fire data from within and beyond the wildfire perimeter are compared with data resampled immediately after the fire, and through the subsequent summer grazing season. Both within and beyond the wildfire perimeter, pre-fire sampling sites will be enhanced with small grazing exclosures to control for the effect of post-fire grazing, allowing assessment of wildfire, grazing, and their interactive effects. The pasture will be stocked with cattle at a moderate stocking rate from mid-May to mid-September 2023.We will measure plant response (forage nutritive quality, photosynthesis), soil response (soil nutrients, soil microbes), and livestock response (grazing distribution, weight gain).Forage Nutritive Quality and Photosynthesis: We will use Near-InfraRed Spectroscopy to evaluate clipped forage samples for forage nutritive quality (crude protein, acid detergent fiber, neutral detergent fiber, and Relative Forage Quality Index).We will use an infrared gas analyzer to measure CO2assimilation and stomatal conductance, and we will measure leaf area and leaf nitrogen concentration.Soil Nutrients and Soil Microbes: Soil samples will be collected with step-in probes to 5 cm at the beginning and end of the grazing season. Pre- and immediate post-burn samples have already been collected. We will evaluate soil nutrient availability via measurements of total carbon and total nitrogen. We also will measure plant-available phosphorus, potassium, calcium, and magnesium. We will use phospholipid fatty acid (PLFA) analysis to assess abundance of soil microbial communities (bactoeria, decomposer fungi, mycorrhizal fungi, protozoans, and actinomycetes).Grazing Distribution and Weight Gain: We will assess grazing distribution with two methods: 1) GPS collars attached to a subset of the cattle herd, and 2) mapping cattle dung density. Cattle weight gain will be determined by comparing individual cattle weights collected at the beginning and end of the grazing season.Data Analyses: We will use mixed-effects regression and multivariate approaches to compare wildfire and grazing effects, and their interactions, within our BACI experimental design.Extension MethodsWe will use co-production science to integrate stakeholder knowledge and perspectives into the research objectives, methods, and data interpretation. We also will include stakeholders (ranchers, natural resource agency personnel, research scientists, Extension educators) in the dissemination of our research results vianews releases, newsletter articles, popular press articles in ranching industry media, Extension seminars, a new Extension bulletin, field days/workshops, refereed journal articles, a scientific conference presentation, and several web postings.