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.

Please cite this article when you use this dataset.

Ikari, S., M. Tomitaka, Y. Kubota, and T. Kenta. (2026). Geospatial Data Layer of Semi-Natural Grasslands With Century-Old or Longer Temporal Continuity. Ecological Research 41, no. 4: e70108. https://doi.org/10.1111/1440-1703.70108. 

Update notes:

For version 2, we identified artificial grasslands, which were identified as semi-natural grasslands in the previous version and filtered them out. This filtering was done for grasslands larger than 10 ha ("old_grassland_japan_larger_than_10ha_filtered_v20260722.geojson"). The non-filtered one contains all grasslands identified following methods described in the peper. Thus, it contains misidentified artificial grasslands ("old_grassland_japan_non_filtered_v20260722.geojson"). The file with >10 ha grasslands filtered and ≤10 ha grasslands unfiltered is also uploaded ("old_grassland_japan_filtered_v20260722.geojson").