Sensitivities of coral reefs in the Verde Island passage to climate change

Abstract

The Verde Island Passage (VIP) is located at the center of marine shorefish biodiversity in the Philippines. It is under tremendous amount of stress from natural and anthropogenic impacts. A vulnerability assessment of the VIP’s coral reef areas to climate change, particularly elevated sea-surface temperatures (SST), increased storminess and sea-level rise (SLR) is presented. Potential impacts on live hard coral cover due to increasing SST ranged from 3% to 22% loss. These projections were based on the high percentage covers of thermally sensitive coral families such as acroporids and pocilloporids. Potential impacts on diversity attributed to high SST ranged from 0.8% to 1.6% based on species-area curves and 10% to 49% based on sensitivities of coral genera from available literature. Estimated live hard coral cover and diversity loss due to the impact of storms ranged from 12.5% to 37.5% and 7% to 22%, respectively. Sea-level rise had the lowest impact on reef cover and diversity, resulting to an estimated loss of 4% to 7% in coral cover and 0.60% to 0.80% in coral diversity. Impact on reef fishes was measured based on their dependence and association with corals. Percentage loss of reef fish species richness and abundance ranged from 9% to 16% and 12% to 54%. These projected impacts on the health and biodiversity of the coral reefs of the VIP are conservative but still significant. The towns and communities surrounding the passage should not be complacent and should increase their efforts to protect and manage their coral reef areas.