Citation
Sea otters: Their role in structuring nearshore communities
TL;DR
Sea otters control sea urchin populations through predation
This paper established sea otters as keystone species in kelp forest ecosystems by comparing Aleutian islands with and without otter populations. The research demonstrated that sea otters, representing less than 0.1% of ecosystem biomass, determine whether kelp forests flourish or collapse into urchin barrens.
The sea otter case became the canonical example of keystone predation, showing how selective predation on sea urchins enables the existence of diverse kelp forest ecosystems supporting hundreds of species.
Key Findings from Estes & Palmisano (1974)
- Sea otters control sea urchin populations through predation
- Without otters, urchins overgraze kelp creating 'urchin barrens'
- Otter presence enables kelp forest ecosystems supporting hundreds of species
- Impact vastly disproportionate to otter biomass (< 0.1% of ecosystem)