ABSTRACT
Viewing parrotfish through the lens of geological and morphological reef development, this chapter discusses the critical role that parrotfishes play in the development of the physical, calcium carbonate, structure of coral reef ecosystems. It shows how, as ecosystem engineers, parrotfish feeding and carbonate recycling activities impact on reef growth exploring the relative contributions of parrotfishes to both coral reef destruction (via bioerosion) and construction (sediment production and reworking). These processes are then considered within a "carbonate budget" framework, to illustrate how parrotfish bioerosion and sediment production roles sit within the overall battle of constructive and destructive forces that determine the outcome for coral reef development. The reader is then shown how factors associated with global change are likely to impact on reef carbonate budgets, with a view to understanding how the contribution of parrotfishes to reef construction and destruction might influence the dynamic balance of reef development in a changing world. Finally, the chapter sets out the overall prognosis for reef development under future climate projections and the roles that parrotfish bioerosion and sediment production are likely to play under such conditions.
