Common Ground for Managing Invasive Annual Grasses

Authors: Monaco, Thomas

Submitted to: Electronic Publication
Publication Type: Other
Publication Acceptance Date: 9/30/2009
Publication Date: 9/30/2009
Citation: Monaco, T.A. 2009. Common Ground for Managing Invasive Annual Grasses. Electronic Publication.

Interpretive Summary:

Technical Abstract: Invasive annual grasses often reach their full biological potential in ecosystems of the western United States. This suggests that crucial ecosystem "checks and balances" are not functioning. In other words, invasion occurs because ecosystems have lost resistance to invasion, and invasive plants are free to dominate and further alter ecosystem processes (Figure 1). Naturally, resource managers need to know 1) Why ecosystems have lost resistance to invasion and 2) What can be done to reduce invasive grass dominance, repair ecosystem processes and prevent reinvasion? Our goal here is to briefly illustrate how both questions can be addressed within the framework of Ecologically Based Invasive Plant Management (EBIPM). The EBIPM framework advocates developing strategies to manage ecosystem succession using knowledge of site availability, species availability, and species performance. Disturbance (size and severity) is the primary process that creates or eliminates site availability through its influence on physical space and resources for invasive species. Fire is one example of how disturbance influences both site availability and species availability (Figure 2). Dispersal, propagation, and establishment characteristics are the primary processes that control colonization and species availability. Modifying factors for species availability include species life history, disturbance regime, and soil surface features. Modifying soil surface features with soil cultivation illustrates how processes driving colonization differentially influence species availability (Figure 3). Finally, understanding how resources, ecophysiology, species life history, stress, and interference regulate species performance will help identify ways to influence successional pathways. Although many factors influence species performance, management activities should strive to reduce the performance of invasive annuals species while fostering the performance of desirable native and introduced plant species. For example, rapid establishment, stress tolerance, and the capacity to compete with invasive annual grasses are important factors that modify species performance (Figure 4). Adopting the EBIPM framework challenges resource managers to identify the underlying causes of plant invasions and develop management strategies that modify key processes, repair ecosystem function, and promote invasion resistance. In addition, the underlying principles of EBIPM provide a scientific 'common ground' that can be adapted to any invasive plant problem. To learn more about how EBIPM is being adopted in the Great Basin as a multi-state cooperative effort to combat invasive annual grasses, please visit www.EBIPM.org.