Geospatial data layer of seminatural grasslands with century-old or longer temporal continuity

This study introduces the first nationwide geospatial dataset of century-old seminatural grasslands in Japan, created by integrating historical land-use maps, contemporary high-resolution spatial data, and expert knowledge. By tracing grassland persistence over more than 100 years, the dataset identifies seminatural grasslands maintained through continuous human management. Comprising 2,654 polygons, the dataset supports grassland conservation prioritization, biodiversity monitoring, and landscape-scale restoration, and is available in GIS-compatible formats for research and policy use under a non-commercial license.The data creation is supported by the Environment Research and Technology Development Fund (JPMEERF20234005) of the Environmental Restoration and Conservation Agency provided by Ministry of the Environment of Japan.The methods are currently available as a preprint.