Fig. 3

Demarcation plant distribution in Ibaraki Prefecture. a Species mentioned in documents written between 1648 and 1867 (n = 42), and b species mentioned by local farmers between 2017 and 2021 (n = 29). To avoid point overlap, the point displacement function was used to illustrate records having the same or similar longitude and latitude information. In such case, points were placed around a centroid (“ + ”)