Urchin barren

An urchin barren is an area of the subtidal where the population growth of sea urchins has gone unchecked, causing destructive grazing of kelp beds or kelp forests (specifically the giant brown bladder kelp, Macrocystis).

Sea urchins eat kelp holdfasts.^[1] This can be caused by a lack of sea otters or other predators in the area,^[2] which makes it extremely important to protect the ecological balance in a kelp forest.

Despite their name, urchin barrens are usually abundant with marine invertebrate life, echinoderms in particular.^[3] Species such as the sunflower starfishes, brittle stars, and the purple sea urchin are common.