Comparing environments in Japanese cities and rural areas using honey DNA analysis and GIS analysis

Beekeeping plays a crucial role in pollination processes and is now acknowledged for its efficiency in assessing the biodiversity of the surrounding environment. This study evaluated vegetation diversity in urban and rural environments using honey DNA metabarcoding and Geographic Information System (GIS) analysis. Honey samples were collected from beehives in Setagaya, Tokyo, and Kimitsu, Chiba, Japan, between March and September 2024. Flower species present in honey were identified through DNA metabarcoding using Next-Generation Sequencing (NGS) and Polymerase Chain Reaction (PCR) techniques, providing information on nectar sources and surrounding vegetation. The results revealed diverse plant communities in both locations and demonstrated that urban Setagaya, despite its developed landscape, supported nectar resources for honeybees. Comparative analysis of samples collected from June to August 2024 highlighted differences in vegetation composition between urban and rural environments. To complement the DNA analysis, GIS-based vegetation assessment was conducted within an approximately 3 km honeybee foraging radius using Ministry of the Environment vegetation survey data. Vegetation coverage was evaluated using the Normalized Difference Vegetation Index (NDVI) and Green Normalized Difference Vegetation Index (GNDVI). The combined approach demonstrated the usefulness of honey DNA analysis and GIS techniques for evaluating environmental diversity and comparing ecological characteristics across different landscapes.