Nationwide diversity of symbolic “city flowers” in Japan is increasing

Recognizing and maintaining locally rooted human–nature interactions is essential for utilizing ecosystem services. Although the general public's awareness of biodiversity and ecosystem services has been examined using various proxies, it remains unclear how local governments—key sectors in creating conservation policies—appreciate them within a solid local context. Here, we focused on the “city flower,” an official symbolic species of Japanese cities, as a new proxy for measuring governmental attitudes toward biota and its services. We aimed to capture temporal changes in the awareness of species with locally relevant value at the city government level by examining the changes in city flowers over more than half a century. Data from the official websites of municipalities, including the names, the adoption years, and the reasons for adoption, revealed two major periods of adoption, with a notable increase in species diversity in and after 1993. This increase could be attributed to a recent reduction in bias toward popular flowers and growing interest in alternative, less popular flowers. Analysis of the reasons for adoption suggested that the temporal change in adopted flower species was related to the increasing emphasis on species with an explicit local context, especially those with instrumental value to the city. Our findings indicate the tendency for local governments to increasingly recognize their biocultural backgrounds and the ecosystem services of plants within their regions. The growing awareness of the local governments regarding their biocultural background is a positive sign for the conservation of biodiversity and ecosystem services.