Pacific Islander societies have long demonstrated resilience when it comes to coping with environmental changes through their vast local knowledge systems, and their context-specific management of local ecosystems. However, increasing population pressures and impacts from climate change have presented new environmental challenges for Pacific Islanders. This has sparked concerns from a number of non-government organisations, international donors, and government agencies to intervene with climate change projects. Despite their efforts, many external interventions have failed to address the long-term needs of Pacific Island communities and embed sustainable livelihood solutions. Given this challenge, innovative solutions that allow local and Indigenous communities to respond and live with changed local conditions and environments are needed. This thesis investigates Indigenous ways of knowing and managing ecosystems and how this can be utilised in future ecosystem-based management and adaptation options. Drawing on iTaukei (Indigenous Fijian) knowledge systems, this thesis focuses on human-mangrove relationships in coastal and rural Fijian villages as a case study. First, a literature review is provided to build important context for the research on mangrove ecosystems and ecosystem-based approaches to adaptation and management. The conceptual framework is then detailed to help contextualise and elucidate the research findings. The three main results chapters then provide an in-depth discussion on the major findings of this thesis and how they link back to the original aim and objectives. The first results chapter examines the local perspectives of iTaukei women and men on mangrove ecosystem services through a gender lens. This presents new insights into how gender and other intersecting factors can influence the ways people use, value, and interact with local ecosystems. The second results chapter explores the socio-ecological changes of mangrove ecosystems and the implications this has for iTaukei communities. It is concluded that when investigating ecosystem changes in subsistence-based communities, a holistic approach which considers socio-ecological systems theory should be taken to truly understand the implications for affected communities. The third results chapter investigates the traditional management techniques used by iTaukei communities to conserve, manage and replenish mangrove ecosystems. This builds on current literature pertaining to the role of local and Indigenous ways of knowing in producing ecosystem-based adaptation and management options that are equitable and sustainable. Overall, this thesis demonstrates that there is work to be done to ensure that management and adaptation interventions effectively address the needs of local and Indigenous communities. In order to truly dismantle the neo-colonialist, top-down approaches to external interventions, the iii decolonisation of research methodologies is vital. Reflecting on lessons learnt, intervening agencies need to collaborate with Indigenous ...