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

Table 1

Kelp density and sea otter prey abundance (individuals per 0.25 m²) in kelp forest and urchin barren communities in the central and western Aleutian Islands, Alaska. N is the mean of prey species counted within 0.25 m² quadrats in each community (𝑛=8 islands with 20 quadrats per community per island). Prey species include Strongylocentrotus polyacanthus (Strongylo.), Pododesmus machrochisma (Pododes.), Mytilus trossulus (Mytilus), Musculus discors (Muscul.), and Fusitriton oregonensis (Fusitrit.). Significant differences from Tukey post hoc comparisons 𝑃≤0.05 level are indicated by (*). NP: Not present.

	Kelp density	N	Abundance (inds.·0.25 m^−2)
	(inds.·0.25 m^−2)		Strongylo.	Pododes.	Mytilus	Muscul.	Fusitrit.
Kelp	5.89±1.14	1.6±1.1	3.8±1.9 *	2.3±1.2	0.9±0.7	0.8±1.1	0.2±0.1
Barren	NP	6.5±2.3	28.6±5.8	2.5±1.5	1.1±0.6	NP	0.3±0.1