Ocean warming over time linked to more tropical fish, increased plant-eating, and kelp loss

Kelp forests have recently disappeared from a warming tropical-temperate transition zone in eastern Australia.

• Herbivory increased as kelp gradually declined and disappeared over a 10-year period of 0.6 °C warming.
• Fish communities in areas where kelp was once abundant became increasingly dominated by tropical herbivores after kelp loss.
• Two key tropical/subtropical herbivores consumed transplanted kelp within hours, indicating their rapid impact on kelp populations.
• There was a notable rise in the abundance of fish that eat algae, along with much higher bite rates at sites lacking kelp.
• Changes in kelp abundance were not directly related to seawater temperatures or other measured environmental factors.

Simplified