Ecosystem structure and processes at Kaloko Honokohau, focusing on the role of herbivores, including the green sea turtle Chelonia mydas, in reef resilience

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 420:27-44 (2010) - DOI: https://doi.org/10.3354/meps08846 Ecosystem structure and processes at Kaloko Honokōhau, focusing on the role of herbivores, including the green sea turtle Chelonia mydas, in reef resilience Colette C. C. Wabnitz1,*, George Balazs2, Sallie Beavers3, Karen A. Bjorndal4, Alan B. Bolten4, Villy Christensen1, Stacy Hargrove2, Daniel Pauly1 1Fisheries Centre, AERL, University of British Columbia, 2202 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada 2Marine Turtle Research Program, NOAA, National Marine Fisheries Service, Pacific Islands Fisheries Science Center, 2570 Dole Street, Honolulu, Hawai’i 96822-2396, USA 3National Park Service, Kaloko-Honok–ohau National Historical Park, 73-4786 Kanalani St., #14, Kailua Kona, Hawai’i 96740, USA 4Archie Carr Center for Sea Turtle Research, and Department of Biology, PO Box 118525, University of Florida, Gainesville, Florida 32611, USA *Email: colette.wabnitz@gmail.com ABSTRACT: The formal protection of the Hawaiian green turtle Chelonia mydas in the 1970s has led to significant increases in the number of individuals recorded throughout the archipelago. Reduced growth rates and poor body condition of individuals at a number of foraging sites, including Kaloko-Honokoōhau National Historical Park (Kaloko), suggest that some aggregations have reached carrying capacity. To better understand the ecological structure and processes of the reef system at the park, we developed an ecosystem model that synthesized available data on Kaloko for the year 2005 and included 26 groups, spanning the entire trophic web. Model results showed that the combined grazing pressure of the different herbivore functional groups (i.e. reef fish, sea urchins, and green turtles) in Kaloko matched total algal production. Sea urchins exerted the strongest control over algal resources, partly because of their large biomass in park waters. Results confirmed that the Kaloko green turtle aggregation has reached carrying capacity. Green turtles help maintain low algal cover, and thus resilience of reefs in the face of disturbance, and should be explicitly included in studies of ecosystem dynamics on reefs. Our work also provides a ‘current-condition’ baseline for Kaloko, and a valuable tool for the assessment of the future marine ecosystem impacts of projected urban expansion plans around the park. KEY WORDS: Marine turtles · Ecosystem-based management · Ecopath · Coral reef · Herbivory · Phase shift · Nutrient enrichment · Kona coast · Hawaii Full text in pdf format Supplementary material PreviousNextCite this article as: Wabnitz CCC, Balazs G, Beavers S, Bjorndal KA and others (2010) Ecosystem structure and processes at Kaloko Honokōhau, focusing on the role of herbivores, including the green sea turtle Chelonia mydas, in reef resilience. Mar Ecol Prog Ser 420:27-44. https://doi.org/10.3354/meps08846Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 420. Online publication date: December 16, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.