Satellite-based mapping of Mikania micrantha presence to support evidence-based management of Terai grasslands, Nepal

Invasive non-native species are one of the top drivers of biodiversity loss, yet our understanding of the extent and mechanisms of invasive spread is often deficient, as is our knowledge of the effectiveness of various interventions and approaches to manage invasion. To help address this knowledge gap, we combined grassland management information with satellite-derived information on the presence of an invasive plant (Mikania micrantha) in a globally significant grassland ecosystem, the Chitwan-Parsa complex in the Terai Arc landscape, and compared the effectiveness of interventions used to control invasion. Mikania micrantha prevalence, which can be reliably mapped using 30cm Pleiades Neo imagery (82.7% overall accuracy), was found to vary substantially depending on the location and management regime, being particularly high in sites that are mowed, or mowed and uprooted (as opposed to unmanaged sites, and sites where burning was used). However, the importance of grassland patch identity in our models had an overall larger impact on Mikania micrantha presence than broader location or management, suggesting that other drivers of Mikania micrantha presence may be more important. Altogether, these findings are highly relevant to the management of other wildlife rich areas across sub-Himalayan grasslands, where many invasive plants are present. Our approach moreover demonstrates the potential for satellite remote sensing to improve our understanding of the impacts of management on invasive species distribution; such insights are critical for informing and justifying appropriate management decisions to conserve species and ecosystems threatened by plant invasions.