Title

State of Corals and Coral Reefs of the Galapagos Islands (Ecuador): Past, Present, and Future

Document Type

Article

Publication Date

8-2018

Publication Title

Marine Pollution Bulletin

Keywords

El Nino-Southern Oscillation, Echinoid bioerosion, Coral recovery, Coral loss, Caulerpa, Overfishing, Galapagos National Park

ISSN

0025-326X

Volume

133

First Page

717

Last Page

733

Abstract

Coral populations and structural coral reefs have undergone severe reductions and losses respectively over large parts of the Galápagos Islands during and following the 1982–83 El Niño event. Coral tissue loss amounted to 95% across the Archipelago. Also at that time, all coral reefs in the central and southern islands disappeared following severe degradation and eventual collapse due primarily to intense bioerosion and low recruitment. Six sites in the southern islands have demonstrated low to moderate coral community (scattered colonies, but no carbonate framework) recovery. The iconic pocilloporid reef at Devil's Crown (Floreana Island) experienced recovery to 2007, then severe mortality during a La Niña cooling event, and is again (as of 2017) undergoing rapid recovery. Notable recovery has occurred at the central (Marchena) and northern islands (Darwin and Wolf). Of the 17 structural reefs first observed in the mid-1970s, the single surviving reef (Wellington Reef) at Darwin Island remains in a positive growth mode. The remainder either degraded to a coral community or was lost. Retrospective analyses of the age structure of corals killed in 1983, and isotopic signatures of the skeletal growth record of massive corals suggest the occurrence of robust coral populations during at least a 500-year period before 1983. The greatest potential threats to the recovery and persistence of coral reefs include: ocean warming and acidification, bioerosion, coral diseases, human population growth (increasing numbers of residents and tourists), overfishing, invasive species, pollution, and habitat destruction. Such a diverse spectrum of disturbances, acting alone or in combination, are expected to continue to cause local and archipelago-wide mortality and degradation of the coral reef ecosystem.

Comments

Research funding was provided to PF, AB, TS, DM and PWG by the U.S. National Geographic Society grant #9738-15, and U.S. National Science Foundation grants OCE-1447306, OCE-9314798 and earlier awards. We acknowledge support of NSF RAPIDgrant OCE-1447306 to continue research through the 2014-16 ENSO.

Additional Comments

A Salute: This article acknowledges the pioneering work of Jerry (Gerard) M. Wellington who was the first to document systematically the occurrence and nature of coral communities and coral reefs in the Galápagos Islands, a biologically diverse and highly valued ecosystem in the Galápagos Marine Reserve.

ORCID ID

0000-0002-6003-9324

DOI

10.1016/j.marpolbul.2018.06.002

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