From planning to implementation: a multi-stakeholder partnership for managing plant invasions in tropical island ecosystems

Effective management of invasive species within protected areas requires innovative solutions. In the Mascarene's archipelago, the national park of Reunion contains the largest area of intact vegetation, which faces alarming threats from invasive alien plant species. In response, the local government initiated an inclusive partnership in 2018 involving decision-makers, managers, and scientists to address the management of invasive alien plant species. An operational framework from planning to implementation has been established encompassing five key steps: (1) conduct a comprehensive site assessment, (2) model future threats, (3) prioritise interventions, (4) implement actions through a multi-stakeholder programme spanning multiple years, and (5) evaluate the effectiveness of implemented interventions. This study provides an in-depth examination of the research-action partnership and the operational framework, illustrating outputs for key priority sites. Our survey covered over 2500 ha, quantifying invasion degree in three vegetation strata at a fine-scale, and revealed significant areas within subalpine vegetation which remain remarkably pristine. By adapting participatory conservation planning approaches, we developed implementation-level outputs at a scale useful for managers which guided interventions on the ground. The partnership exemplifies a transdisciplinary approach with a broad array of stakeholders. Drawing from a checklist of essential components for successful partnerships, we highlight key insights from this initiative, providing valuable lessons for managing invasions in other regions. This framework holds promise for addressing several Global Biodiversity Framework Targets concerning plant invasions in island ecosystems or within landscapes characterised by multi-layered governance.