Trophodynamics of Eastern Pacific Coral Reefs

Abstract

Trophic interactions on eastern Pacific coral reefs are complex and highly dynamic, ever changing due to numerous biological and physical factors. In this chapter, we first address the sources of energy at the base of food webs, i.e. photosynthetic carbon fixation by benthic algae and endosymbiotic zooxanthellae, secondarily derived organic deposits, detritus, and fecal matter, as well as demersal (within reef) and allochthonous plankton food sources. Next we consider consumers, covering the major reef trophic guilds in the eastern Pacific---suspension feeders, deposit and detritus feeders, herbivores, carnivores (predators and carnivorous grazers), as well as scavengers. The diversity and relative abundance of consumer taxa are described and considered in terms of their ecological roles in community processes. The complex interplay of these guilds is examined through food webs constructed for Panama, Cabo Pulmo reef in the Gulf of California, Mexico, and the Floreana Island rocky reef in the Galápagos Islands. Finally, the effects of physical and biotic perturbations on food webs, interactions, indirect effects, and trophic cascades conclude this review.