The Probability of an Unrecoverable Coral Community in Dongsha Atoll Marine National Park Due to Recurrent Disturbances

Yu-Rong Cheng,Chi-Hsiang Chin,Chao-Kang Wang,Ding-Fa Lin

doi:10.3390/su12219052

Abstract

In recent decades, coral reefs worldwide have been impacted annually by climate change and anthropogenic impacts. Marine parks are utilized to protect coral reef ecosystems and to ensure it is in sustainable use. In the present study, a 15-year change in coverage and composition of a hard coral community at Dongsha Atoll Marine National Park (DAMNP) was examined from 2005 to 2019. The reef has experienced several disturbances, including 11 typhoons and six coral bleaching events. A 34.39% decline in coral coverage had been recorded over the past 15 years in response to multiple and recurrent natural disturbances. The coral communities and functional ecology of the Dongsha Atoll changed during this period. The average dissimilarities in coral communities ranged from 55.38 to 59.02%. The dramatic decrease in the abundance of branching corals in addition to a slight increase in massive and encrusting corals suggest the habitat has simplified. The degraded coral reef communities represent a low resilience ecosystem, even though the DAMNP has been established. Without effective management, the coral reef ecosystem of the Dongsha Atoll may not persist due to repeated impacts from recurrent disturbances.

Highlights

Coral reefs, the tropical rainforests of the sea, are one of the most productive ecosystems on Earth, providing important services to fisheries, coastal protection, medicines, and tourism [1]
It was predicted that most coral reef ecosystems will suffer from severe bleaching events every year, and the impact level will exceed the extent of the 1998 bleaching event by the year 2040 [2]
It appears these degraded coral reef ecosystems suffered from escalating pressures at a global scale, which have led to an intense discussion on the strategies to conserve the biodiversity, enhance the resilience, and maintain the ecosystem processes in these habitats [3,4,6,7]

Summary

Introduction

The tropical rainforests of the sea, are one of the most productive ecosystems on Earth, providing important services to fisheries, coastal protection, medicines, and tourism [1]. Despite having established the DAMNP, the Dongsha reef has suffered from natural and anthropogenic disturbances, including typhoons [21], coral bleaching events [22,23,24], illegal fishing (poisons and explosives) and overfishing [25,26,27], the proliferation of macroalgae [28], outbreaks of the coral predator Acanthaster planci Linnaeus 1758 (crown-of-thorns starfish) [29], and coral diseases or parasites [30]. These disturbances have continued to degrade the coral-dominated assemblages in the DAMNP waters. We were interested in whether recurrent disturbances played a major role in the state of coral communities (coral coverage, biodiversity, species composition, and ecological functions), especially in three different periods: before DAMNP establishment (in 2006), the period of the following five years (2006 to 2012), and the period of the following twelve years (2006 to 2019)

Study Site

Species Diversity of the Corals

Coral Communities from 1998–2007

Coral Communities from 2007–2012

Findings

Statistical Analysis