Tropical rabbitfish and the deforestation of a warming temperate sea

A striking example of climate-mediated range shifts in marine systems is the intrusion of tropical species into temperate areas worldwide, but we know very little about the ecological consequences of these range expansions. In the Mediterranean Sea, the range expansion of tropical rabbitfishes that first entered the basin via the Suez Canal provides a good example of how tropical herbivorous fish can impact the structure of rocky bottoms in temperate seas. Two species of rabbitfishes have now become a dominant component of total fish biomass in the southernmost part of the eastern Mediterranean. Experimental evidence shows these species can profoundly transform benthic communities, turning algal forests into ‘barrens’, but the specific mechanisms that facilitate this shift have not been established. We surveyed ~1000 km of coastline in the eastern Mediterranean and identified two clearly distinct areas, a warmer group of regions with abundant tropical rabbitfish and a colder group of re...