Climate change: underwater forest decline

Wernberg T., Smale D. A., Tuya F., Thomsen M. S., Langlois T. J., de Bettignies T., Bennett S. & Rousseaux C. S. (2013) An extreme climatic event alters marine ecosystem structure in a global biodiversity hotspot. Nature Clim. Change 3, 78-82.

Aim: 
To test the impacts of an extreme marine heat wave on benthic and fish communities in a cool and a warm location.
Type of Study: 
Natural experiment (before-after comparison)
Key Results: 
The marine heat wave had substantial effects on benthic and fish communities at the northern (warm) location but not at the southern (cool) location. Forest-forming seaweeds declined (~50% loss) in abundance whereas turf seaweeds increased (~100% increase). There was an increase (~100% incraese in 'tropicalisation index') in the proportion of warm-affinity fishes.
Treatments: 
Surveys before an after the marine heat wave at different geographical locations
Response: 
n/a
Models: 
n/a
Reviewer: 
Thomas Wernberg
Locations: 
Southwestern Australia, Jurien Bay & Hamelin Bay
Response variable : 
Percent cover of benthos (functional groups), counts of fish (species)
Replication: 
2 regions ~600km apart, 3 sites kilometres apart in each region. Benthos: 6 x 0.5m2 quadrats per site fish: 3 x 25m transecs per site
Ecosystem: 
Temperate reef
Full Reference: 
Wernberg T., Smale D. A., Tuya F., Thomsen M. S., Langlois T. J., de Bettignies T., Bennett S. & Rousseaux C. S. (2013) An extreme climatic event alters marine ecosystem structure in a global biodiversity hotspot. Nature Clim. Change 3, 78-82.