Threats to cycad biocultural heritage in the Amami Islands, Japan

We are pleased to introduce this paper, which has been selected as an Editor’s Choice.

Species are products of evolution, and once they are lost due to extinction, they can’t be recovered. Unfortunately, the actions of humans have threatened species worldwide in various ways, and one indirect method has been the unintentional introduction of invasive species. A species is “invasive” when it enters a habitat that is not where it evolved. In the absence of natural predators, ecological pressures, or competitors, invasive species may proliferate without control, directly harming native species or indirectly consuming resources necessary for their survival. A case of biological invasion in Japan occurred recently in 2021, when the cycad aulacaspis scale (CAS) insect was detected on the Amami-Oshima and Okinawa-jima, in the Ryukyus. As its name suggests, CAS feeds on cycad plants —and is voracious—, consuming cycads until causing their death. Many places in the islands, historically abundantly populated by the native cycad Cycas revoluta, are now being devastated by this invasion. Many cycad populations are threatened and at risk of extirpation if the invasion is not controlled. But what does it mean when a species is threatened? Of course, losing a species due to the action of humans is a disgraceful event; a part of evolution is lost, and species removal may cause the extinction of other ecologically associated species (pollinators, for example). However, it is also important to consider cases where the threatened species is a significant symbol and a cornerstone of a culture's identity. This is the case of the cycads in the Ryukyus. Cycads have a strong historical significance for the culture of this region: people use them as a source of food, as materials to craft tools, and as a symbol of their local identity. The cycad culture in Japan is already in decline due to an aging demography, migration from rural to urban areas, and modernity in general. With the CAS invasion, the cycads and the culture around them are more threatened than ever, and conservation actions are necessary. In this article, we discuss that biological conservation is not only concerned with our responsibility to take care of nature, but also to take care of cultural identities. Cultures are entangled with their local biodiversity, and joining efforts from scientists in the natural and humanities sciences can help us see the whole picture. Interdisciplinarity is crucial in conservation.