Doctoral Dissertation Research: Contesting Weeds: Conservation and Indigenous Knowledge and Use of the Environment in Samoa

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Mikania micrantha is a rapid growing vine that is native to Central and South America but which has spread throughout the tropics. This species has had a major impact on the economies and environments of several regions of the world, especially in South Asia, Southeast Asia and throughout the Pacific islands. In South Asia especially, the plant is a major threat to silviculture, and researchers in many parts of the world are searching for biotic controls. In Samoa, this species appeared during the 1920s and is now the most common weed in the archipelago. Farmers here, however, have incorporated M. micrantha into the shifting cultivation system, where it is used as cover, mulch and cattle forage. Additionally, people use this species medicinally. Implementation of biotic controls risks depriving the rural population of a valuable natural resource. With the goals of conservation and indigenous use at odds, this study will engage the theory and methods from cultural, political and landscape ecology to answer several questions. First, the project will assess whether M. micrantha poses a risk to Samoa's various habitat types in general or whether it is restricted mainly to areas of human disturbance. This will be assessed through stratified random sampling in each vegetation type. Aerial photographs, field mapping and GIS will also be used to construct the mosaic of habitat patches and corridors and, in conjunction with the sampling, will be used to construct a testable model of the distribution of M. micrantha. Second, the study will assess the dimensions of human use of this species. The investigation here will gather both biophysical and ethnographic data. Each field in the study village will be mapped and vegetation and soil samples will be taken, to assess the feedbacks between plant communities and soil. Interviews with each of the farmers will be conducted to assess how they manage the plant communities in their fields, especially regarding whether M. micrantha is actively managed for its specific advantages, actively managed against as an undesirable weed, or simply adapted to as a means of making the best of a bad situation. Finally, the study will utilize ethnographic techniques to investigate how each farmer is situated in power laden social networks and how this feeds into the farmers' decision-making. The study will examine the networks for accessing land (form of land tenure), acquiring inputs, disposing of agricultural outputs (through subsistence and/or marketing), and knowledge (whether traditional, educational or government extension). The study crosses several biophysical and social scales, from the microscale (field, patch, household) to mesoscale (village, landscape mosaic) and macroscale (biological invasions, national and international environmental policy and discourse). This analysis links social, political and economic forces to the individual decision-makers that shape the landscape mosaic.Mikania micrantha is a species that is impacting the environment and economies of several tropical countries, but little is known about it. This study in Samoa serves as a unique opportunity to investigate this species such that it will inform a variety of disciplines from diverse perspectives. This investigation will inform the broader research into invasive species, especially in terms of studying this biological invasion in the context of human dominated ecosystems and the social dimensions of this domination across several scales of interaction. Furthermore, this study will elucidate factors that can be used to determine whether an invasive species is a threat that must be dealt with or whether it is benign or even beneficial; implementing control of invasive species simply because they are invasive species may impose a greater cost on society than is necessary. Finally, the study will bring to light the local knowledge and practices surrounding this species that can inform more equitable environmental policy. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.