Open AccessA linked land-sea modeling framework to inform ridge-to-reef management in high oceanic islands
Author(s) -
Jade Delevaux,
Robert Whittier,
Kostantinos A. Stamoulis,
Leah L. Bremer,
Stacy D. Jupiter,
Alan M. Friedlander,
Matthew Poti,
Greg Guannel,
Natalie Kurashima,
Kāwika B. Winter,
Robert J. Toonen,
Eric Conklin,
Chad C. Wiggins,
Anders Knudby,
Whitney Goodell,
Kimberly Burnett,
Susan H. Yee,
Hla Htun,
Kirsten L.L. Oleson,
Tracy N. Wiegner,
Tamara Ticktin
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0193230
Subject(s) - reef , coral reef , environmental issues with coral reefs , resilience of coral reefs , oceanography , fringing reef , coral reef protection , environmental science , coral reef organizations , coralline algae , aquaculture of coral , fishery , ecology , geography , geology , biology
Declining natural resources have led to a cultural renaissance across the Pacific that seeks to revive customary ridge-to-reef management approaches to protect freshwater and restore abundant coral reef fisheries. Effective ridge-to-reef management requires improved understanding of land-sea linkages and decision-support tools to simultaneously evaluate the effects of terrestrial and marine drivers on coral reefs, mediated by anthropogenic activities. Although a few applications have linked the effects of land cover to coral reefs, these are too coarse in resolution to inform watershed-scale management for Pacific Islands. To address this gap, we developed a novel linked land-sea modeling framework based on local data, which coupled groundwater and coral reef models at fine spatial resolution, to determine the effects of terrestrial drivers (groundwater and nutrients), mediated by human activities (land cover/use), and marine drivers (waves, geography, and habitat) on coral reefs. We applied this framework in two ‘ridge-to-reef’ systems (Hā‘ena and Ka‘ūpūlehu) subject to different natural disturbance regimes, located in the Hawaiian Archipelago. Our results indicated that coral reefs in Ka‘ūpūlehu are coral-dominated with many grazers and scrapers due to low rainfall and wave power. While coral reefs in Hā‘ena are dominated by crustose coralline algae with many grazers and less scrapers due to high rainfall and wave power. In general, Ka‘ūpūlehu is more vulnerable to land-based nutrients and coral bleaching than Hā‘ena due to high coral cover and limited dilution and mixing from low rainfall and wave power. However, the shallow and wave sheltered back-reef areas of Hā‘ena, which support high coral cover and act as nursery habitat for fishes, are also vulnerable to land-based nutrients and coral bleaching. Anthropogenic sources of nutrients located upstream from these vulnerable areas are relevant locations for nutrient mitigation, such as cesspool upgrades. In this study, we located coral reefs vulnerable to land-based nutrients and linked them to priority areas to manage sources of human-derived nutrients, thereby demonstrating how this framework can inform place-based ridge-to-reef management.