Kelp Forests versus Urchin Barrens: Alternate Stable States and Their Effect on Sea Otter Prey Quality in the Aleutian Islands

Figure 4

Sea urchin potential energy density per unit area and potential energy density per individual urchin from remnant kelp forest and urchin barren communities throughout the central and western Aleutian Islands. Significant differences at 𝑃≤0.05 level are indicated by (*).