WRRC Seminar

Managing for Island Resilience through Scenario Planning with Linked Land-Sea Models

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Declining natural resources have led to a cultural renaissance across the Pacific that seeks to revive customary ridge-to-reef management approaches to promote social and ecological resilience in the face of climate change. Effective ridge-to-reef management requires decision-support tools to evaluate the combined effects of terrestrial, marine, and human drivers on coral reef ecosystems. Although a few applications have linked the effects of land uses to coral reef ecosystems, the spatial resolution of these remains too coarse to inform ridge-to-reef management at a watershed-scale for small Pacific Islands. To address this gap, we developed a novel land-sea modeling framework based on local data, and coupled groundwater models with coral reef predictive models at fine spatial resolution. We applied the framework to two ahupua‘a in Hawaii with community-based management (Hā‘ena and Ka‘ūpūlehu), but subject to different rainfall and wave disturbance regimes. Specifically, we assessed the effects of terrestrial drivers (freshwater and nutrients), marine drivers (waves, local geography and habitat), and human drivers (coastal development) on these two representative coral reef communities. Our results indicated that coral reef communities subject to low rainfall and wave power are founded primarily on corals and habitat topography, while communities driven by high rainfall and wave power are dominated by crustose coralline algae. As a result of limited dilution and mixing from low rainfall and wave power, places like Ka‘ūpūlehu, may be more vulnerable to increases in land-based nutrients from coastal development. Although Hā‘ena benefits from mixing and dilution due to high freshwater and wave power, the sheltered back-reef areas, which represent important nursery habitat for fishes, may also be vulnerable to increases in land-based nutrients. This study shows how terrestrial and marine drivers can shape diverse ridge-to-reef systems under different natural disturbance regimes, thereby highlighting the importance of place-based management.

Event Sponsor
Water Resources Research Center, Mānoa Campus

More Information
(808) 956-3097, morav@hawaii.edu

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