Forest Invasive Plant Management: Understanding And Explaining Management Effects

Abstract

Invasive plant management aims to protect native communities through reducing the negative ecological impacts of invaders. However, reduced invasive plant populations do not necessarily translate into stronger native communities; management can even negatively impact native plants. Unfortunately, management outcomes are rarely documented, limiting our ability to link management practices with effects. My study of Northeastern U.S. forest invasive plant management organizations used manager's experiential knowledge to discover what management practices most influence success as defined by three distinct outcomes: prevention of new species establishment, reduction of invasive species populations and protection of native species. During the survey managers also described their program resources and competencies. Surprisingly, supportive management actions, those occurring before and after the main invasive species removal, not treatment actions, most influenced success. For preventing establishment, targeting multiple invasive species, frequently mapping invasive species, and starting management in isolated areas increased success. For reducing invasive populations and for protecting native species, the most important action was frequent and continued post-project management. This suggests that attempts to improve treatment actions are unlikely to result in better management outcomes. Instead, management needs to be conceptualized as a long-term program where all aspects of management are important; including mapping, monitoring and continued management. This requires a large shift in behavior which will be difficult because the current organizational structure and funding system evaluate manager performance based on quantity of invasive plants removed not long-term management effects. Change will only be possible if organizational and funding structures incorporate measures of management effectiveness, ecosystem impacts, and learning into their standards of performance.