Cultural keystone species as a tool for biocultural stewardship. A global review

The cultural keystone species (CKS) concept (i.e. ‘species that shape in a major way the cultural identity of a people’ as defined by Garibaldi and Turner in 2004) has been proposed as part of a common framing for the multiple entangled relationships between species and the socioecological systems in which they exist. However, the blurred and prolific definitions of CKS hamper its univocal application. This work examines the current use of the term CKS to reconcile a definition and explore its practical applications for biocultural stewardship. We ran a search for the words ‘cultural’ AND ‘keystone’ AND ‘species’. Our search was limited to peer‐reviewed articles published in English between 1994 and 2022 (inclusive) and was conducted using Google Scholar, PubMed, Scopus and Web of Science. We extracted and analysed bibliometric information as well as information on (i) the CKS components, (ii) humans' support for CKS and (iii) the definitions of CKS. From the 313 selected documents, the CKS concept appears to be increasingly accepted, as evidenced by a growing corpus of literature. However, the absence of a systematic and precise way of documenting CKS precludes global cross‐cultural comparisons. The geographical distribution of authors using the concept is biased. We found that 47% of all the CKS reported and 38% of the works identified in our review were located in North America. Beyond ‘supporting identity’, several other of nature's contributions to people are associated with the CKS definitions. However, the contributions of the sociocultural group to the survival and conservation of the CKS (i.e. stewardship) are made explicit only in one‐third of the documents reviewed. To advance biocultural stewardship as a conservation paradigm, we suggest (a) defining CKS as an indissoluble combination of a non‐human species and one or more sociocultural groups; (b) acknowledging that species and sociocultural group relations should be classified in a continuum, according to gradients of relationship intensity; and (c) explicitly acknowledging the reciprocal relationships between sociocultural groups and species. Read the free Plain Language Summary for this article on the Journal blog.