Concerned about the rapid rates of extinction of biological species and human languages throughout the world, environmental scientists, activists and policymakers have recently become interested in understanding the links between biodiversity and cultural diversity. Some scholars maintain that the two kinds of diversity are interactive, interdependent and possibly coevolved, a viewpoint expressed in the emerging concept of biocultural diversity. The implications of this insight for conservation policy are obvious: protection of organic nature and human culture should proceed hand in hand. The hypothesis of biocultural diversity draws support mainly from macro-geographical studies showing a strong spatial correlation between species richness and number of endemic languages when tabulated by country or when plotted on a world map. Despite this intriguing evidence, the nature and extent of the linkage between diversity in the natural and the cultural realms at smaller spatial scales are still not well understood. Correlation does not necessarily indicate causation and we do not know whether the observed overlaps really refect mutual determination (e.g. coevolution of ecological communities and human societies over time), asymmetrical causation from one side to the other (e.g. unique cultural adaptations to biogeographical characteristics versus anthropogenically modified landscapes), analogous but independent phenomena caused by third factors (e.g. fragmentation of habitat types and socioethnic territories caused by mountains, islands or climatic conditions), or some combination of these.