Question

Ecologists from the Woods Hole Marine Oceanographic Institute conducted a study looking at the cleaning mutualism between cleaner fish and reef fish in Jamaica. In their study, they found the surprising result below between the presence of cleaner fish at reefs and reef fish diversity (H’). What ecological concept do these data support?

Reef fish species diversity (H') present Cleaner fish absent Cleaner fish

Habitat heterogeneity causes a reduction in species diversity

Cleaner fish are keystone species

Reef fish are foundation species

Reef fish community structure is not influenced by mutualistic interactions

Answer 1

Reef fish are foundation species. This means that the reef fishes help in establishing a survival foundation to the coral reef areas in the oceans. The keystone cleaner fish species, irrespective of their abundant nature, as a disproportionate effect on the marine ecosystem. Normally removal of a keystone species decreases overall density of the prey population. Now according to the graph, in presence of a cleaner fish, the species diversity of reef fishes are more than during the ansence of cleaner fish.

This is an example of apparent competition. In this kind of relationship, increase in the diversity of one species causes decrease in the diversity of other species due to enhanced predation by a shared predator.