This APN project investigated land-to-sea nutrient pathways affecting freshwater, coastal, and coral reef ecosystems in Ra Province, Fiji, with a focus on Navolau District. The project was developed in response to growing concerns in island settings that land-based pollution, in the form of agricultural runoff via groundwater discharge, may be contributing to nutrient enrichment in coastal waters and coral reef environments. In Pacific Island communities, coral reefs provide essential ecosystem services, including fisheries, coastal protection, cultural value and livelihood support. However, these reef systems are increasingly threatened by climate change, land-use change and local pollution pressures.
The project adopted a ridge-to-reef approach, connecting land-based activities in villages, farms, rivers, groundwater systems, coastal zones, fringing reefs and barrier reefs. Field activities included community engagement, land-use observations, river and groundwater surveys, coastal water sampling and reef-related nutrient assessments. Surveys were conducted across land-based sites, river systems, fringing reef environments and barrier reef areas. The project also incorporated local knowledge from village communities, including observations of river conditions, flooding, waste movement, coastal changes and reef-related concerns. This helped link scientific measurements with lived community experience.
Preliminary findings indicate that land-based nutrient inputs are a significant concern in the study area. Excess nutrient concentrations were detected at barrier reef sites at levels that may threaten juvenile coral survival and reduce reef recovery potential. Fringing reef environments were found to be severely degraded and, in some areas, almost absent, potentially due to substantial sediment accumulation that may smother juvenile corals and inhibit reef regeneration. These findings highlight the urgent need for improved land-management practices and targeted interventions to reduce nutrient and sediment inputs from land to the coastal environment.
The project also identified several visible land-based pollution pathways. Rubbish dump sites were observed near rivers, and waste was found caught in trees and vegetation along higher downstream riverbanks. This suggests that flood events transport waste from riverbank dumping areas downstream toward coastal environments. Agricultural areas, particularly sugarcane farms, may also contribute nutrients through runoff, erosion and fertiliser loss. Groundwater and submarine groundwater discharge remain important hidden pathways because they can transport dissolved nutrients from land to coastal waters even outside major rainfall or flood events. However, the results indicate that rivers are the dominant pathway delivering nutrients and pollutants to the reefs in this study area, rather than SGD. Therefore, future management efforts should place greater emphasis on adaptation and resilience measures for surface-water pathways, including riverbank restoration, riparian buffer zones, improved waste management and flood-sensitive land-use planning.
The community component revealed an important management dilemma: communities generally understood which activities and substances contributed to coral reef degradation, yet many continued to rely on the same practices because they remained central to household livelihoods and agricultural production. In particular, chemical-based farming practices were recognized as environmentally harmful but continued to be widely used because they provide economic security and reliable income.
This highlights the limitation of awareness-based interventions alone. While communities expressed willingness to change, alternative practices must also be economically viable. The findings therefore point to the need for economic incentive-based nature-based solutions, where environmental restoration is linked with supplementary or alternative livelihood opportunities like filter feeder aquaculture and mariculture projects. Examples could include seaweed, sea-grape cultivation, oyster or giant-clam farming, mangrove-related livelihoods or other locally appropriate activities that reduce pressure on land and reef systems while providing tangible economic benefits to communities.
Overall, this project provides an important baseline for understanding nutrient pollution and reef vulnerability in Navolau District. It demonstrates that coral reef protection in Fiji requires integrated ridge-to-reef management that addresses both visible river-based pollution and hidden groundwater nutrient pathways, while strengthening collaboration among communities, researchers and government stakeholders in Ra Province and the wider Pacific region.
