Chapter 15 - Coral Reef Systems and the Complexity of Hazards

Abstract

Coral reefs are unique coastal systems as they represent the balance between ecological and physical processes. Known for their high biological diversity, both the ecology and geomorphic structure of reef systems support a range of ecosystem services. This chapter explores the complexities of hazards in reef systems, underpinned by an understanding of the dynamic interplay between ecological and physical processes. Key drivers of impact in reef systems are examined, which include extreme events and slow-onset changes in the environmental boundary conditions of reefs. Natural hazards, incremental environmental change, and anthropogenic stresses can each drive significant impacts on reefs. Case studies indicate that the degree of impact is temporally and spatially variable dependent on the antecedent condition of reefs. Impacts include the catastrophic loss of living reef cover, erosion of adjacent coastlines, the formation of extensive rubble deposits on reefs, and slow deterioration in reef health, leading to structural collapse of reef systems. However, coral reef systems are resilient to natural and anthropogenic perturbations, and the recovery period of reefs to a range of impacts is highlighted. This chapter also discusses how the resilience of reefs can be compromised through the compounding effect of natural and anthropogenic stresses on reefs that can force major changes in reef health and structure over decadal timescales. A reef system model is used to highlight this complexity and allows for consideration of factors such as impact and recovery timescales in reef systems.