Performing Department
Plant Sciences
Non Technical Summary
Cheatgrass (or downy brome) is one of the most widespread and problematic invasive weeds in the western United States affecting wildlife habitat, livestock production and ecosystem processes. Although it has been present in Wyoming since the early 1900s, a recent emphasis has been placed on managing cheatgrass in the state. Although individual projects have been accomplished with varying success, a state-level strategy has not been articulated. Given limited budgetary and human resources, a strategic approach to effectively deploy limited resources to areas with high recovery potential is needed. This project will combine local expert knowledge, existing ecological data, and field studies with ecological and spatial modeling to categorize areas of Wyoming into several categories: cheatgrass free, minor cheatgrass, high cheatgrass with persistent perennial plants, apparent cheatgrass monoculture. These categories will be overlain with important wildlife, conservation and agricultural information to determine areas of high leverage for cheatgrass management. In addition to this prioritization, a replicated experiment will compare multi-species targeted livestock grazing to herbicide control to evaluate its use as a cheatgrass management tool in Wyoming.
Animal Health Component
0%
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
The primary research goals of this study are to develop a statewide prioritization plan for management and restoration of cheatgrass-invaded rangelands and to investigate the utility of targeted livestock grazing as a tool to reduce cheatgrass in rangeland systems. A targeted grazing study will complement the statewide prioritization project by providing Wyoming-specific information on the use of targeted grazing as a management practice. Information will be used to develop guidelines for landowners, local, state and federal agencies working on the restoration of cheatgrass infested communities in Wyoming. The outreach and extension potential of this project is equally, if not more, important than the research goals. The use of grazing as a tool to reduce cheatgrass infestations is a concept that is discussed frequently at many producer meetings in Wyoming, yet very little quantitative information has been produced to support or refute the approach. Specifically, the proposed research will address the following questions: 1. Which areas of Wyoming present the highest leverage opportunities to manage cheatgrass through prevention, control or restoration We will combine local expert knowledge, existing data, field surveys and ecological/spatial modeling to develop a statewide cheatgrass prioritization approach. 2. What are the effects of intensive grazing on cheatgrass survival and reproduction We will use replicated grazing cells to concentrate livestock in a cheatgrass-dominated area to evaluate the impacts of intensive grazing on cheatgrass and associated vegetation. 3. Do different types of livestock impact cheatgrass populations differently We will compare cattle grazing, sheep grazing, and multi-species grazing impacts directly within the experiment. 4. How does targeted grazing compare to herbicide treatment for reducing cheatgrass populations We will include two standard herbicide treatments widely accepted to manage cheatgrass within the experimental design for a direct comparison of targeted grazing to herbicide. 5. What impacts have our extension programming had at the local and state level We will disseminate research findings through face-to-face meetings, state and regional conferences, publications and other media outlets. We will evaluate programmatic effectiveness through traditional extension approaches.
Project Methods
The statewide cheatgrass prioritization project will be a statewide effort incorporating field sampling, local expert knowledge and ecological modeling to classify areas into different states of cheatgrass infestation with accompanying estimates of recovery potential. The project will include multiple steps to provide a more accurate picture of the cheatgrass challenge in Wyoming. Ideally, we will be able to develop a state-level strategy, but the initial phase may need to be focused on a smaller scale (two regions). To develop a spatially-explicit prioritization at the landscape scale, we will: 1) Integrate local expert knowledge, existing cheatgrass data and other ecological data to develop a draft map showing four states of invasion and accompanying management approaches. 2) Field data collection to evaluate draft prioritization. 3) Use data from field sampling, remote sensing, and previous projects to develop a predictive model, stratified by region, of the four invasion states in Wyoming. This model will be used to identify areas of high risk for cheatgrass dominance, and to prioritize areas for management action and increased field data collection in the future. These data will be used in conjunction with habitat indicators to develop further prioritization for management. The targeted grazing study will be established in a degraded pasture dominated by cheatgrass at SAREC in Lingle, WY. The experiment will be established as a randomized complete block design with cheatgrass control methods as the experimental treatments with three replicates. Grazing treatments will be comprised of a combined livestock x timing treatment, whereas herbicide treatments will consist of one preemergent application of two selected herbicides in the fall of 2013. Grazing treatments will be implemented to achieve heavy utilization of cheatgrass each fall, spring or both fall and spring for at least a two year period within each treatment. Given the small size of each treatment plot, we plan to implement grazing treatments within a one-week time frame for each grazing bout. Initial vegetation evaluation will be conducted prior to implementation of any treatments. We will install a permanent transect in the center of each experimental plot and record canopy and basal cover by species at 100 points along each transect. We will clip, dry and weigh biomass production by functional group (cheatgrass, perennial grasses, forbs and shrubs) in four 0.25-m2 quadrats within each experimental plot. We will also count cheatgrass density in four 0.1-m2 quadrats within each experimental plot and collect cheatgrass seeds at the time of seed maturation to determine the effects of each treatment on seed production. Since cheatgrass is an annual species, population persistence is dictated by seed production from year to year.