Kelp forests support diverse marine communities of sentient fish and invertebrates and are declining from urchin barrens, warming oceans, and pollution.
The collapse of kelp forests from urchin barrens eliminates the complex three-dimensional habitat that diverse communities of sentient fish and invertebrates depend on. Fish species that cannot survive in barren urchin habitats are displaced or starve as their foraging environment disappears. Sea otters whose prey disappears with kelp forest decline face nutritional stress. The welfare cascade from kelp ecosystem collapse affects thousands of species simultaneously. Restoration of sea otter populations in kelp forests provides a natural mechanism for controlling urchins and maintaining ecosystem health.