With this in mind, we examined casualties and temporal changes of coral reef ecosystem regime change over a long-time perspective in Port Resolution, Tanna Island.

We identified twenty-seven key influential factors and their corresponding causal relationships. Subsequently, we analysed the coral reef regime shift under four scenarios representing major climatic and non-climatic trajectories.

Our findings show that climatic factors, including sea-level rise, ocean warming and acidification, extreme ocean events, temperature and rainfall pattern are the most influential factors impacting the health and resilience of coral reefs which are mostly beyond the local communities and authorities' control. However, protecting Port Resolution's reef site from climate-driven regime shifts only is not sufficient to guarantee the stability of provided ecosystem servicesecosystem services Ecosystem services are the goods and services provided by nature which are experienced as or transformed into benefits for human society. They are generally classed as 'provisioning' (material things that are consumed), 'regulating' (non-material benefits derived from habitat functioning), and 'cultural' (non-material benefits obtained from an experience of nature, including tourism). including coral reef fisheries, coastal protection and tourism.

Among the major ecosystem services provided by coral reefs, subsistence and commercial coral reef fisheries are more vulnerable to shifts from coral dominance to other undesirable dominance. Among the local factors, unsupervised and uncontrolled tourism activities could dramatically accelerate the shifting process from the coral-dominant condition. Considering the future tourism development plans to enhance the tourism carrying capacity, immediate action to preserve coral reef health and resilience is needed to uphold the attractivity of reef sites to tourists as well as to protect the coral reef communities and sustain other provided ecosystem services.

Moreover, although preserving coral reefs can better support local well-being as an effective and suitable ecosystem-based climate change adaptation option, it is critical to consider other additional local interventions in the absence of any global effort to mitigate climate change impacts, such as ridge-to-reef catchment management plans, improved agricultural approaches or mangrove restoration.