Establishment of a No-take area (NTA) could not guarantee the preservation of coral communities in Chinwan Inner Bay, Penghu, Taiwan

Abstract

No-take areas (NTAs) are an increasingly prevalent approach to conserve coral reefs, but are not always a guarantee of preserving pristine conditions if the area lacks ecological resilience, proper management, or both. In this study, the NTA of a subtropical coral community at Chinwan Inner Bay (CIB), Penghu, Taiwan, established in 2005, showed a 5-fold decline in living coral cover from 80.9% ± 10.8% in 2001 to 16.3% ± 8.4% by 2008 with the dominant coral functional group shifting from branching species to columnar and massive species. Analyses of fish functional groups and macroinvertebrates showed strong signs of overharvesting. In addition, an outbreak of and nearly 4-fold increase in the corallivorous gastropod, Drupella spp., from 5.5 individuals (ind.)/m2 in 2003 to 22.7 ind./m2 in 2009, was believed to be responsible for the disappearance of major coral functional groups at CIB. Depletion of fish and invertebrate functional groups, the outbreak of a corallivorous gastropod, and previously existing and continuing anthropogenic-induced degradation of the marine environment suggest that the overall loss of ecological resilience provided little chance for the coral community to bounce back to the pristine status described in 2001, even after the CIB NTA was formally established in 2005.