Valuing invasives: understanding the Merremia peltata invasion in post-colonial Samoa

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Kirkham, William Stuart

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Merremia peltata has been identified as an invasive species of environmental concern in several Pacific Island countries, and several environmental agencies are seeking means of controlling it. The species is native to this region, and very little is known about it, scientifically. This study investigates some fundamental questions about the invasion from a biogeographic perspective, such as causes of the invasion, both natural and anthropogenic, and prospects for remediation. Given that biological invasions are acknowledged to be a human driven phenomenon, the study also examines cultural and political aspects of the invasion, including perspectives on the plant across several social scales and exploring the social context in which the problem has been identified and addressed. Methods thus employ both biogeographic and ethnographic approaches. Aerial photographs and GIS and field mapping (traditional and GPS) were employed to develop a stratified random sample of vegetation plots. Vegetation cover and environmental data were gathered. Cluster Analysis and Nonmetric Multidimensional Scaling (NMS) were used to analyze the vegetation data. Cultural immersion, progressive contextualization and Q- methodology were employed in ethnographic analysis. Biogeographic results indicate that the dominance of Merremia peltata on the landscape is driven by fluctuating patterns of disturbance on the landscape. Disturbance is seen to be the driving force behind the changing character of floral biodiversity through its interaction with the reproductive and dispersal habits of the plant species. This disturbance arose from changes in patterns of land use as the regional economy shifted from colonial to post-colonial patterns contributed to M. peltata’s dominance. Village level planters and local ecologists are less concerned about this species dominance on the landscape than regional ecologists are. Lingering power inequalities from the colonial period between the core and peripheral countries in the region give more weight to the core perspectives becoming enacted, effectively intervening in these landscapes to protect their own. Recommendations for managing Merremia peltata in situ are given, including aiding successional processes.