Invasive plants are a major land management problem in the Western U.S. Cheatgrass (Bromus tectorum) is the most prominent and problematic invader in cold deserts, with negative effects on rangeland fire patterns, wildlife habitats, and forage/vegetation. Red brome (B. madritensis) is an invader in the Mojave Desert, and can similarly introduce a new fire patterns to sensitive warm desert scrub. These invasions often cause management agencies to incur high costs for prevention, control, restoration, and fire responses. Control and prevention of invasive species is challenging because the risk of invasive plants becoming abundant depends on existing plant communities, climate and weather, land use, and fire history. Moreover, scientific [...]
Summary
Invasive plants are a major land management problem in the Western U.S. Cheatgrass (Bromus tectorum) is the most prominent and problematic invader in cold deserts, with negative effects on rangeland fire patterns, wildlife habitats, and forage/vegetation. Red brome (B. madritensis) is an invader in the Mojave Desert, and can similarly introduce a new fire patterns to sensitive warm desert scrub. These invasions often cause management agencies to incur high costs for prevention, control, restoration, and fire responses.
Control and prevention of invasive species is challenging because the risk of invasive plants becoming abundant depends on existing plant communities, climate and weather, land use, and fire history. Moreover, scientific information on invasion risk that does exist has not always been translated into maps that planners and resource managers can use in their decision making. Broad-scale information is needed to link geographic variation in climate and disturbances (e.g. fire) to decisions on the ground regarding where to apply treatments aimed at limiting the impacts of invasions and restoring native plant composition.
This project aims to use existing datasets to understand the links between the abundance of major plant invaders and climatic extremes, land use and fire history. The project team will examine how the drivers and limits of plant abundance vary among invasive species and across the Great Basin and Mojave Desert. For example, where is cheatgrass likely to be limited by drought and temperature extremes, and are those areas vulnerable to red brome invasion? Where should we be most concerned about annual grass invasion following wildfire? The project’s main objectives are to (i) describe the climatic conditions under which plant invaders occur and reach high abundance; (ii) model spatial variation in the drivers of invader abundance; and (iii) develop map products linking risk of high invasive plant cover to resource management strategies (e.g. prevention, restoration, or tolerance).
Plant invasions in the Intermountain West alter fire regimes and degrade wildlife habitat and forage values. Targeting invasion control and prevention efforts is challenging because the risk of invasive plants becoming abundant depends on existing plant communities, climate and weather, land use, and fire history. Although the general form of these interactions may be understood conceptually, the critical question of identifying ‘where’ remains: variation in invasion risk is not always translated into maps that planners and managers can use. A broad-scale, geographic perspective is needed to link geographic variation in climate and disturbance to decisions on the ground regarding where to apply treatments aimed at limiting the impacts of invasions and restoring native plant composition. The lack of a geographic perspective is particularly acute for the effects of climate and weather extremes, which are known to affect invasion risk and the grass-fire cycle but have not been linked to invasive plant abundance at broad scales.
Our work will leverage existing datasets to link the abundance of major plant invaders to climatic extremes, as well as to land use and fire history. We will ask how the drivers and limits of invader abundance vary among invasive species and across the Great Basin and Mojave Desert. For example, where is cheatgrass (Bromus tectorum) likely to be limited by drought and temperature extremes, and are those areas vulnerable to red brome (B. madritensis) invasion? Where should we be most concerned about annual grass invasion following wildfire? Our focus on invasive plant abundance will extend previous studies of species’ occurrence, because it is the abundance of invasive plants that affect their ecological and economic impacts, as well as potential control strategies. Our work will inform management by providing a nuanced spatial perspective on invasion risk for current and potential invaders.
Project Extension
parts
type
Technical Summary
value
Invasive plant abundance can be sensitive to climatic means and extremes, but the locations on the landscape where climatic processes are likely to limit or promote invasions are coarsely known. We propose to link large existing datasets on invasive plant cover, climate and weather, land use, and fire history to develop spatial maps of invasion risk for several problematic invasive species. Our objectives are to (i) describe the climatic conditions under which focal invaders occur and reach high abundance; (ii) model spatial variation in the drivers of invader abundance; and (iii) develop mapped products linking risk of high invasive plant cover to management strategies that emphasize local protection, prevention, restoration, or tolerance. Background for our work is provided by existing conceptual models of vegetative states and transitions and by empirical studies of how climate and weather affect cheatgrass (Bromus tectorum). These areas of existing research will help us select key variables and interactions to include in our models, and will guide the development of indices of climatic means and extremes. Our methodological approach is based on spatial statistical models, which allow the effects of each driver to vary over space, and an integrated and iterative communication strategy in which our methods and products will be shaped and refined based on partner feedback. Products will include a peer-reviewed publication and maps of invasion risk. These maps will depict spatial variation in the drivers of invader abundance within the Great Basin and Mojave Desert. Results will be integrated to develop a spatially-explicit guide for decision-making given climatic extremes and disturbances. Our products will be refined through a participatory science workshop and consistent communication with managers, and results will be disseminated at a management-focused conference, via websites and webinars, and via continuing outreach efforts. Our work reflects a collaboration between USGS and NatureServe scientists, and aligns with the priorities of our partners at the BLM and the Great Basin LCC.