Controlling an invasive plant at the edge of its range: towards a broader understanding of management feasibility

Abstract

Invasion biologists often think about feasibility of weed control in purely ecological terms, while land managers’ feasibility definitions are further informed by social, policy, and institutional considerations. We use the case of cheatgrass (Bromus tectorum) in the Eastern Sierra Nevada in California to examine the origins and practical significance of differences between scientific and managerial definitions of feasibility. A serious invasive weed and a major ecological threat to the region, cheatgrass in the Eastern Sierra still exists in the kinds of low-density patches that are technically amenable to containment through active management. Yet land managers in this region dominated by public land are not using active management. We conducted a study of the reasons for the apparent disconnect between management potential and management realities, combining semi-structured interviews of public land managers in the region with analysis of the policy and institutional landscape in which land managers operate. We found that managers are concerned about cheatgrass impacts on the region but face a number of barriers to the deployment of useful spread prevention techniques. The de-prioritization of cheatgrass, which is not listed as a noxious weed under either California or federal law, along with resource constraints exacerbated by such policy de-prioritization form one important set of barriers. Certain substantive and procedural requirements of federal and state environmental law form another barrier: they can limit swiftness and flexibility of managerial action and make managers more hesitant to launch such action; they also provide a venue for public opposition to herbicide-based management or directly restrict managers’ access to useful herbicide treatments. We end with some thoughts on increasing the feasibility of cheatgrass control in eastern California. Many of these are broadly relevant to improving invasion management on public lands.