Climate change: underwater forest decline

Vergés A., Tomas F., Cebrian E., Ballesteros E., Kizilkaya Z., Dendrinos P., Karamanlidis A. A., Spiegel D. & Sala E. (2014) Tropical rabbitfish and the deforestation of a warming temperate sea. J Ecol 102, 1518-27.

Aim: 
To determine how tropical rabbitfish abundance is related to sea surface temperature. To relate changes in rabbitfish abundance to benthic community composition and to quantify feeding patterns and preferences of native temperate herbivorous fish vs. invasive tropical rabbitfish.
Type of Study: 
Surveys and manipulative experiment
Key Results: 
Identification of two clearly distinct ares: a warmer group of regions with abundant tropical rabbitfish and a colder group of regions where these consumers were absent/ extremely rare. In regions with abundant rabbitfish, canopy algae were 65% less abundant, and there was a 60% reduction of overall benthic biomass (algae and invertebrates) and a 40% decrease in total species richness. Video-recorded feeding experiments showed that temperate native herbivores exhibited greater grazing rates, but tropical rabbitfish fed complementarily on both established macroalgae and on epilithic algae containing macroalgal recruits
Treatments: 
Cold, algal-dominated unimpacted region vs. warm, barren, 'tropicalized' region
Response: 
Authors highlight importance of assessing the functional traits of range-shifting species to determine potential mechanisms of impact on ecological communities
Models: 
ANOVA, Hotelling's T2 test
Reviewer: 
Adriana Vergés
Locations: 
Eastern Mediterranean (Turkey & Greece)
Response variable : 
Fish species (identity, size category, abundance, biomass), benthic biomass, community metrics (richness, trophic level), grazing rates, SST
Replication: 
3 replicates fish surveys, 4 replicates benthic quadrats, 29 -32 filmed feeding preference assays
Ecosystem: 
Temperate reef
Full Reference: 
Vergés A., Tomas F., Cebrian E., Ballesteros E., Kizilkaya Z., Dendrinos P., Karamanlidis A. A., Spiegel D. & Sala E. (2014) Tropical rabbitfish and the deforestation of a warming temperate sea. J Ecol 102, 1518-27.