Setting conservation priorities in Fiji: Decision science versus additive scoring systems

There is a well-established scientific field - decision science - that can be used to rigorously set conservation priorities. Despite well-documented shortcomings, additive scoring approaches to conservation prioritization are still prevalent. This paper discusses the shortcomings and advantages of both approaches applied in Fiji to identify priorities for terrestrial protected areas. The two main shortcomings of using a scoring approach (discussed in Keppel (2014) [1]) that are resolved with decision science approaches (presented in Klein et al. (2014) [2]) in Fiji were (1) priorities did not achieve one of the most important stated conservation goals of representing ~40% of Fiji's major vegetation types and (2) the weighting of different selection criteria used was arbitrary. Both approaches considered expert knowledge and land-sea connections important to decision makers in Fiji, but only decision science can logically integrate both, in addition to other important considerations. Thus, decision makers are urged to use decision science and avoid additive scoring systems when prioritizing places for conservation. Fiji has the opportunity to be a global leader in using decision science to support integrated land-sea planning decisions

Predicting climate-sensitive water-related disease trends based on health, seasonality and weather data in Fiji

Leptospirosis, typhoid and dengue are three water-related diseases influenced by environmental factors. We examined whether seasonality and rainfall predict reported syndromes associated with leptospirosis, typhoid and dengue in Fiji. Poisson generalised linear models were fitted with s6 early warning, alert and response system (EWARS) syndromic conditions from March 2016 until December 2020, incorporating seasonality, temperature and rainfall. Watery diarrhoea, prolonged fever and suspected dengue displayed seasonal trends with peaks corresponding with the rainy season, while bloody diarrhoea, acute fever with rash and acute jaundice syndrome did not. Seasonality was the most common predictor for watery and bloody diarrhoea, prolonged fever, suspected dengue, and acute fever plus rash in those aged 5 and over, explaining between 0.4 % – 37.8 % of the variation across all conditions. Higher rainfall was the most common predictor for acute fever plus rash and acute jaundice syndrome in children under 5, explaining between 1.0 % – 7.6 % variation across all conditions. Each EWARS syndromic condition case peak was associated with a different rainfall lag, varying between 0 and 11 weeks. The relationships between EWARS, rainfall and seasonality show that it is possible to predict when outbreaks will occur by following seasonality and rainfall. Pre-positioning of diagnostic and treatment resources could then be aligned with seasonality and rainfall peaks to plan and address water-related disease outbreaks

Optimized fishing through periodically harvested closures

1. Periodically harvested closures (PHCs) are a traditional form of fisheries management that improve fishing efficiency during harvests, partly by reducing fish wariness to fishers during closed periods. However, whether PHCs also result in high yields and healthy marine ecosystems is unknown, even as PHCs are being promoted as a culturally appropriate management tool in the Indo-Pacific.2. We integrated field-derived estimates of change in fish wariness into a bioeconomic fisheries model to quantify to what degree PHCs can maximize harvest efficiency, fisheries yield and fish stock biomass.3. Our model indicated that PHCs that had a closure period of one to a few years between a single pulse harvest were able to generate equivalent fisheries yield and stock biomass levels, with greater harvest efficiency than was able to be achieved using permanent closures and other fisheries management tools.4. Fish life-history traits had little impact on the optimality of PHCs in maximizing the triple objective of harvest efficiency, fisheries yield and stock abundance, with overfishing similarly having little effect at anything under extreme levels. Under moderate overfishing, there was a trade-off between PHCs, which maximised harvest efficiency, and no-take permanent closures that maximised yield. However, the former outweighed the latter, and only at extreme levels of overfishing, where stock was reduced to < 18 % of unfished biomass, were permanent closures favoured over PHCs

Forest conservation delivers highly variable coral reef conservation outcomes

Coral reefs are threatened by human activities on both the land (e.g., deforestation) and the sea (e.g., overfishing). Most conservation planning for coral reefs focuses on removing threats in the sea, neglecting management actions on the land. A more integrated approach to coral reef conservation, inclusive of land–sea connections, requires an understanding of how and where terrestrial conservation actions influence reefs. We address this by developing a land–sea planning approach to inform fine-scale spatial management decisions and test it in Fiji. Our aim is to determine where the protection of forest can deliver the greatest return on investment for coral reef ecosystems. To assess the benefits of conservation to coral reefs, we estimate their relative condition as influenced by watershed-based pollution and fishing. We calculate the cost-effectiveness of protecting forest and find that investments deliver rapidly diminishing returns for improvements to relative reef condition. For example, protecting 2% of forest in one area is almost 500 times more beneficial than protecting 2% in another area, making prioritization essential. For the scenarios evaluated, relative coral reef condition could be improved by 8–58% if all remnant forest in Fiji were protected rather than deforested. Finally, we determine the priority of each coral reef for implementing a marine protected area when all remnant forest is protected for conservation. The general results will support decisions made by the Fiji Protected Area Committee as they establish a national protected area network that aims to protect 20% of the land and 30% of the inshore waters by 2020. Although challenges remain, we can inform conservation decisions around the globe by tackling the complex issues relevant to integrated land–sea planning

Trade-offs between data resolution, accuracy, and cost when choosing information to plan reserves for coral reef ecosystems

Conservation planners must reconcile trade-offs associated with using biodiversity data of differing qualities to make decisions. Coarse habitat classifications are commonly used as surrogates to design marine reserve networks when fine-scale biodiversity data are incomplete or unavailable. Although finely-classified habitat maps provide more detail, they may have more misclassification errors, a common problem when remotely-sensed imagery is used. Despite these issues, planners rarely consider the effects of errors when choosing data for spatially explicit conservation prioritizations. Here we evaluate trade-offs between accuracy and resolution of hierarchical coral reef habitat data (geomorphology and benthic substrate) derived from remote sensing, in spatial planning for Kubulau District, Fiji. For both, we use accuracy information describing the probability that a mapped habitat classification is correct to design marine reserve networks that achieve habitat conservation targets, and demonstrate inadequacies of using habitat maps without accuracy data. We show that using more detailed habitat information ensures better representation of biogenic habitats (i.e. coral and seagrass), but leads to larger and more costly reserves, because these data have more misclassification errors, and are also more expensive to obtain. Reduced impacts on fishers are possible using coarsely-classified data, which are also more cost-effective for planning reserves if we account for data collection costs, but using these data may under-represent reef habitats that are important for fisheries and biodiversity, due to the maps low thematic resolution. Finally, we show that explicitly accounting for accuracy information in decisions maximizes the chance of successful conservation outcomes by reducing the risk of missing conservation representation targets, particularly when using finely classified data

Habitat change mediates the response of coral reef fish populations to terrestrial run-off

Coastal fish populations are typically threatened by multiple human activities, including fishing pressure and run-off of terrestrial pollution. Linking multiple threats to their impacts on fish populations is challenging because the threats may influence a species directly, or indirectly, via its habitats and its interactions with other species. Here we examine spatial variation in abundance of coral reef fish across gradients of fishing pressure and turbidity in Fiji. We explicitly account for multiple pathways of influence to test the alternative hypotheses that (1) habitat moderates predation by providing shelter, so habitat loss only affects prey fish populations if there are abundant predators, (2) habitat change co-drives biomass of both prey and predator functional groups. We examined responses of 7 fish functional groups and found that habitat change co-drives both predator and prey responses to turbidity. Abundances of all functional groups were associated with changes in habitat cover; however, the responses of their habitats to turbidity were mixed. Planktivore and piscivore abundance were lower in areas of high turbidity, because cover of their preferred habitats was lower. Invertivore, browser and grazer abundance did not change strongly over the turbidity gradient, because different components of their habitats exhibited both increases and decreases with turbidity. The effects of turbidity on fish populations were minor in areas where fish populations were already depleted by fishing. These findings suggest that terrestrial run-off modifies the composition of reef fish communities indirectly by affecting the benthic habitats that reef fish use

Diversification of refugia types needed to secure the future of coral reefs subject to climate change

Identifying locations of refugia from the thermal stresses of climate change for coral reefs and better managing them is one of the key recommendations for climate change adaptation. We review and summarize approximately 30 years of applied research focused on identifying climate refugia to prioritize the conservation actions for coral reefs under rapid climate change. We found that currently proposed climate refugia and the locations predicted to avoid future coral losses are highly reliant on excess heat metrics, such as degree heating weeks. However, many existing alternative environmental, ecological, and life-history variables could be used to identify other types of refugia that lead to the desired diversified portfolio for coral reef conservation. To improve conservation priorities for coral reefs, there is a need to evaluate and validate the predictions of climate refugia with long-term field data on coral abundance, diversity, and functioning. There is also the need to identify and safeguard locations displaying resistance toprolonged exposure to heat waves and the ability to recover quickly after thermal exposure. We recommend using more metrics to identify a portfolio of potential refugia sites for coral reefs that can avoid, resist, and recover from exposure to high ocean temperatures and the consequences of climate change, thereby shifting past efforts focused on avoidance to a diversified risk-spreading portfolio that can be used to improve strategic coral reef conservation in a rapidly warming climate

Opportunities and constraints for implementing integrated land–sea management on islands

Despite a growing body of literature on integrated land-sea management (ILSM), very little critical assessment has been conducted in order to evaluate ILSM in practice on island systems. Here we develop indicators for assessing 10 integrated island management principles and evaluate the performance of planning and implementation in four island ILSM projects from the tropical Pacific across different governance structures. We find that where customary governance is still strongly respected and enabled through national legislation, ILSM in practice can be very effective at restricting access and use according to fluctuations in resource availability. However, decision-making under customary governance systems may be vulnerable to mismanagement. Government-led ILSM processes have the potential to design management actions that address the spatial scale of ecosystem processes and threats within the context of national policy and legislation, but may not fully capture broad stakeholder interests, and implementation may be poorly coordinated across highly dispersed island archipelagos. Private sector partnerships offer unique opportunities for resourcing island ILSM, although these are highly likely to be geared towards private sector interests that may change in the future and no longer align with community and/or national objectives. We identify consistent challenges that arise during island ILSM planning and implementation and offer recommendations for improvement

Highly Variable Taxa-specific Coral Bleaching Responses to Thermal Stresses

Complex histories of chronic and acute sea surface temperature (SST) stresses are expected to trigger taxon- and location-specific responses that will ultimately lead to novel coral communities. The 2016 El Niño-Southern Oscillation provided an opportunity to examine large- scale and recent environmental histories on emerging patterns in 226 coral communities distrib- uted across 12 countries from East Africa to Fiji. Six main coral communities were identified that largely varied across a gradient of Acropora to massive Porites dominance. Bleaching intensity was taxon-specific and was associated with complex interactions among the 20 environmental variables that we examined. Coral community structure was better aligned with the historical temperature patterns between 1985 and 2015 than the 2016 extreme temperature event. Addi- tionally, bleaching responses observed during 2016 differed from historical reports during past warm years. Consequently, coral communities present in 2016 are likely to have been reorganized by both long-term community change and acclimation mechanisms. For example, less disturbed sites with cooler baseline temperatures, higher mean historical SST background variability, and infrequent extreme warm temperature stresses were associated with Acropora-dominated communities, while more disturbed sites with lower historical SST background variability and frequent acute warm stress were dominated by stress-resistant massive Porites corals. Overall, the combination of taxon-specific responses, community-level reorganization over time, geographic variation, and multiple environmental stressors suggest complex responses and a diversity of future coral communities that can help contextualize management priorities and activities