Impacts of environmental changes on the global distribution of coral reefs

Abstract

Coral reefs support high biological diversity of marine life, and are highly productive ecosystems. Environmental perturbations exert profound influence on coral reefs. Elucidating environmental limits for coral growth and understanding the response of reef habitat suitability to environmental change are central to projecting future impacts of climate change on coral reef ecosystems and their biogeography under changing environmental conditions. I use the diagnostic model ReefHab in combination with most recent environmental variables to define the coral reef tolerance limits. By using the global data of coral reef occurrence as a proxy for their long-term adaptation to contextual environmental conditions, I calculate the reef habitat suitability functions. Then I explore the impact of global warming and ocean acidification on the potential reef habitat and habitat suitability in combination with ensemble data of IPCC AR5 climate models. I also explore the combined effects of pairwise combinations of environmental factors on coral reefs. This thesis contributes to knowledge on the tolerance limits for coral reefs and the parametric function of reef habitat suitability.