Critical issues and new challenges for research and management of invasive plants in the Pacific Islands

Abstract

Invasive alien species are recognized as a major threat to island biodiversity and ecosystem functions worldwide, with well-documented, detrimental impacts on the native biota of Oceania. Despite their high number and rapid increase in the Pacific Islands, invasive alien plants (IAP) have received less attention by researchers, managers, and the general public compared to invasive animals (e.g., predatory mammals). Indeed, although lists of IAP in natural and agroecosystems have been set up in most island countries and territories, their ecological and socio-economical impacts are still not well documented and/or popularized. Very few IAP eradication successes have been reported, and postcontrol monitoring and cost-benefit analysis are often missing. Moreover, most of the published studies have been conducted in the Hawaiian and the Galápagos islands. This essay is a call for more research and management efforts on IAP in Oceania, especially in the small tropical Pacific Islands. Focal areas should not only include species bioecology, control strategies and methods and prioritization systems (including risk assessments), but also better understanding of island ecosystems functioning (e.g. forest dynamics and resilience), with the integration of past and present anthropogenic and natural disturbances. The importance of “novel” ecosystems, where natural habitats have been partially or totally modified by humans, and the potential effects of climate change on terrestrial ecosystems should be addressed, and new conservation and management strategies defined in the Pacific Islands, in order to try to halt biodiversity erosion in highly vulnerable island ecosystems.