Strengthening rural community water safety planning in Pacific Island countries: evidence and lessons from Solomon Islands, Vanuatu, and Fiji.

Pacific Island Countries (PICs) collectively have the lowest rates of access to safely managed or basic drinking water and sanitation globally. They are also the least urbanised, have dynamic socioeconomic and increasing climate-linked challenges. Community-based water managers need to respond to variability in water availability and quality caused by a range of hazards. Water Safety Planning (WSP), a widely adopted approach to assessing water supply, offers a risk-based approach to mitigating both existing and future hazards. WSP is adaptable, and making modifications to prescribed WSP to adapt it to the local context is common practice. Within the Pacific Community Water Management Plus research project, we used formative research and co-development processes to understand existing local modifications, whether further modifications are required, and, to develop additional modifications to WSP in Fiji, Vanuatu and Solomon Islands. The types of additional local modifications we recommend reflect the unique context of PICs, including adjusting for community management of water supplies and required collective action, community governance systems, levels of social cohesion in communities, and preferred adult-learning pedagogies. Incorporating modifications that address these factors into future WSP will improve the likelihood of sustained and safe community water services in Pacific and similar contexts.

Stomata Are Driving the Direction of CO2-Induced Water-Use Efficiency Gain in Selected Tropical Trees in Fiji.

Understanding plant physiological response to a rising atmospheric CO2 concentration (ca) is key in predicting Earth system plant-climate feedbacks; however, the effects of long-term rising ca on plant gas-exchange characteristics in the tropics are largely unknown. Studying this long-term trend using herbarium records is challenging due to specimen trait variation. We assessed the impact of a ca rise of ~95 ppm (1927-2015) on the intrinsic water-use efficiency (iWUE) and maximum stomatal conductance (gsmax) of five tropical tree species in Fiji using the isotopic composition and stomatal traits of herbarium leaves. Empirical results were compared with simulated values using models that uniquely incorporated the variation in the empirical gsmax responses and species-specific parameterisation. The magnitude of the empirical iWUE and gsmax response was species-specific, ranging from strong to negligible. Stomatal density was more influential than the pore size in determining the gsmax response to ca. While our simulation results indicated that photosynthesis is the main factor contributing to the iWUE gain, stomata were driving the iWUE trend across the tree species. Generally, a stronger increase in the iWUE was accompanied by a stronger decline in stomatal response. This study demonstrates that the incorporation of variation in the gsmax in simulations is necessary for assessing an individual species' iWUE response to changing ca.