• Energy Research

Coral reefs are vulnerable to the impacts of global climate change (e.g rising sea temperature) as well as to numerous local disturbances (e.g overfishing). In combination, these impacts are known to degrade coral reefs, compromising critical ecosystem functions and leading to the potential loss of biodiversity and associated ecosystem services. Management aims to minimise these negative effects but is challenged by substantial uncertainty about the relative contribution and interactions among the various types of stressors on coral reefs. One of the most widely applied management tools on coral reefs are Marine Protected Areas (MPAs). MPAs restrict certain or all types of human activities within their boundaries and are aimed at rebuilding degraded habitats, maintaining ecosystem functions, and protecting healthy reefs to ensure the continued provision of ecosystem services. However, using MPAs effectively requires an understanding of their optimal placement to ensure the conservation of biodiversity and ecological functions in support of local communities and stakeholders. My thesis addresses this topic by developing a novel marine spatial planning approach that integrates reef ecosystem services explicitly into the decision-making process.The first chapter of my thesis is a general introduction that provides an overview of current scientific knowledge about the vulnerability of coral reefs and how these ecosystems are likely to respond to various impacts from global and local stressors. Chapter 2 is focused on investigating the response of coral communities to global and local disturbances more explicitly by using an ecological model to examine the impacts of sea surface temperature, local thermal stress, cyclone, fishing pressure, nutrient enrichment and crown of thorns starfish (CoTS) outbreaks on reefs under alternative climate scenarios by examining applied to Indonesian coral reefs. We used three greenhouse gas emissions (Representative concentration pathway - RCP8.5, RCP4.5, and RCP2.6) for the scenarios of climate change. Reefs are likely to experience further declines in coral cover under all alternative scenarios of climate change and local thermal regimes, but with varied rates of decline in different geographic locations. Management benefits were greater under the more pessimistic greenhouse gas emission scenario RCP8.5 and management of two local stressors with complementary ecological targets (i.e., coral recruitment and adult mortality) provided greater benefits than utilizing tools with similar modes of action. For example, combining approaches that targeted CoTS and either fishing or nutrients, that affect adult mortality and recruitment (respectively), had far greater efficacy than targeting the duality of fishing and nutrients, which both influence recruitment only. The results provide new insight into the importance of applying management tools that address different ecological processes.In Chapter 3, I establish a generally applicable MPA design approach to reconcile multiple reef ecosystem services under explicit consideration of local community needs. Using Selayar Island, South Sulawesi (Indonesia) as a case study, I found that the design of MPAs to address all three ecosystem services – biodiversity, fisheries productivity, and coastal protection – proved challenging. Relatively few reefs exhibit high values of all three services and optimization software is needed to seek network locations that achieve reasonable trade-offs between services. Local fishers valued fisheries benefits over biodiversity and coastal protection. Finding MPA networks that deliver fishers’ preferences was particularly difficult if attempting to include the highest levels of fisheries benefit. Compromising on the magnitude of fishery benefits provided much greater flexibility in the choice of MPA networks that delivered moderately high benefits across all services. Moreover, it becomes more challenging to find good solutions as the target level of MPA coverage increases from 10% to 30%, implying that fewer good solutions occur.In Chapter 4, I examine the extent to which governance factors and management processes, such as involvement of the local community in conservation planning and prior experience with MPAs, influence the perceived benefits of MPAs for fisheries. I incorporate governance factors and preferred MPA distribution based on interviews of local fisher communities. The results reveal that the better engagement of the community into the MPA planning process and governance of MPAs lead to a more positive perception of MPA benefits by fishers. Yet fishers’ perceptions of MPAs were more nuanced. Generally, the perceptions were less positive (1) in fishers that fish more frequently, and (2) fishers operating larger boats that include pelagic fishing (cf. fishers using small-scale artisanal methods). It is hypothesized that pelagic fishers are less invested in the benefits of MPAs and that fishers operating more frequently might be less likely to notice modest changes in productivity should it occur.I also asked whether fishers with a more positive perception of MPA benefits would be more likely to locate future MPAs closer to their fishing grounds. However, this simple hypothesis was not supported. Fishers in Selayar recommend a minimum average distance of ~5 km of MPAs from fishing grounds while people involved in MPA planning tended to suggest distances about 8 km farther from fishing grounds. The absence of a simple relationship between fisher perceptions and the separation of MPA-fishing grounds implies that other – unmeasured – factors are responsible. In general, our findings emphasize the importance of incorporating governance processes and social factors into MPA designation.In Chapter 5, I review my conclusions and consider their broader implications and needs for further work. Prioritising multiple reefs for multiple ecosystem services is challenging and therefore the use of optimisation software is necessary to find suites of MPAs that can meet such diverse objectives. A willingness to compromise on the absolute magnitude of fisheries benefits – the ecosystem service of the greatest value to the community – led to far greater flexibility in finding MPA solutions. Overall, tackling more complex sets of objectives is feasible but requires the use of standard optimisation software to select reasonable solutions. Yet management implementation, such as MPA design, requires good governance and an increasing reliance on sophisticated tools has the potential to undermine the transparency and inclusivity of the implementation process. Future studies will need to consider the communication of tools usage as well as the development of frameworks to apply the tools effectively.