No evidence for food limitation of Caribbean reef sponges: Reply to Slattery & Lesser (2015)

Slattery & Lesser (2015; Mar Ecol Prog Ser 527: 275-279) offer a Comment on our review of the literature for evidence of bottom-up control of sponge communities on Caribbean reefs. We briefly address the criticisms presented in the Comment and reiterate the lack of evidence for food limitation, including inter-oceanic comparisons of Caribbean reefs with Indo-Pacific oligotrophic reefs, where sponge communities show strong evidence of food limitation, and past and recent evidence for the importance of dissolved organic carbon (DOC) in sponge nutrition. We did not claim that 'predation is the primary process that determines the growth, biomass and biodiversity of sponges on Caribbean coral reefs,' but we identified 3 depth-related factors that influence sponge community structure on Caribbean reefs: turbulence, spatial competition and predation. We agree that multifactorial manipulative experiments are the best way to address the interaction between top-down and bottom-up processes in this system; indeed, one such experiment has been performed, with an outcome that does not support bottom-up effects.