The Role of Climate in Shaping Invasive Plant Abundance across Different Spatial Locations
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).