Issue 102:6 of Journal of Ecology is online now. The latest Editor’s Choice paper was chosen by Editor Amy Austin and the paper is “Tropical rabbitfish and the deforestation of a warming temperate sea” by Vergés et al. Associate Editor Yvonne Buckley has written a commentary on the paper below.

Rock slime and Rabbitfish

A tropical herbivore moves north, invading warmer areas and devouring the diverse native vegetation. Invaded areas are denuded and barren, the native herbivores nowhere to be seen. Who would have thought the rather cutely named rabbitfish would have such a devastating impact?

Close-up of a rabbitfish juvenile (photo credit: Zafer Kizilkaya)

Soon after the Suez canal opened tropical rabbitfish species entered the Mediterranean and spread into the warmer areas. Vergés et al. not only documented and mapped the impact of tropical rabbitfish in the Mediterranean in relation to sea surface temperature but carried out some neat experiments and video-taped fish feeding behaviour to determine the mechanism of impact. Why do these range-shifting herbivores devastate the macro-algal forests – is it a greater consumption rate or a difference in the way they eat? Underwater cameras were used to catch the rabbitfish in the act.

Invasive rabbitfish in Turkey (photo credit: Zafer Kizilkaya)

There were small differences in the amount of macroalgal biomass removed by the native and non-native species, but the big difference in eating patterns was that one particular species of rabbitfish consumed the “rock slime” or Epilithic Algal Matrix at a very high rate. Rock slime is a nursery for macroalgae, so the rabbitfish were eating the baby algae, preventing recruitment.

Dr Fiona Tomas and Dr Adriana Vergés setting up feeding preference experiments in barren Adrasan (Turkey), where algal forests are nowhere to be found. (photo credit: Murat Draman).

When invaders find an unexploited niche they can have a very large impact. As species move around in response to climate change, we may expect more unexpectedly large impacts, particularly as species which have evolved in more diverse communities move into less diverse temperate ecosystems where not all of the potential niches are filled.

Yvonne Buckley
Associate Editor, Journal of Ecology