How do piscivorous fish assemblage, species richness, and density impact indirectly invertebrate prey consumption by invertivores in coral reef environment?

While numerous studies have noted the potential for cascading impacts resulting from piscivorous fish depletion from coral reef food webs (Jackson 2001, Jackson et al. 2001, Bascompte et al. 2005), few have been able to detect the hypothesized cascading impacts of piscivore depletion (Jennings and Polunin 1997). I hypothesize that this lack of evidence can be the cumulative result of the emergent properties of diverse predator and prey assemblages in these habitats, which has been shown to weaken trophic cascades in some occasions (Finke and Denno 2004, Duffy et al. 2005) or that inappropriate scale (Levin 1992) or metrics used in previous studies may have biased the results. Combining traditional community ecology metrics and experimental measurements of foraging efficiency, I evaluate the direct impacts piscivore richness and density on the composition and relative abundances on midlevel consumers and indirectly on the survival of their potential invertebrate prey. This approach conducted on a previously untested fore-back reef scale, as well as combining traditional community measures to a process, may be more suitable for studying top-down impacts in diverse communities with numerous trophic linkages, such as coral reefs.