Fig. 2.

Regional distribution of study classifications linked to cultural keystone species theory (n = 238). Study classifications include (1) studies that solely mention the cultural keystone species concept, (2) studies that mention a given species as a cultural keystone species without a direct test or measure of species cultural keystone status, (3) studies that cite a paper on or that discusses the cultural keystone concept, (4) studies that review the cultural keystone species concept, and (5) studies that provide a direct test or measure of species cultural keystone status