This study examined the feasibility of introducing a small‑scale anaerobic digestion system using food waste in a fishing village in Ehime Prefecture that is transitioning toward becoming a marginal settlement. The evaluation was conducted from both environmental (GHG emissions) and economic perspectives. Two scenarios were proposed in which all digestate is utilized within the community as fertilizer for home gardens and citrus cultivation. Continuous anaerobic digestion experiments using artificial food waste demonstrated stable methane production; however, the results also indicated a potential deficiency of potassium among the fertilizer components of the digestate. From an environmental standpoint, greenhouse gas emissions were found to increase by 15–18% compared with incineration, due to emissions associated with the electricity required to heat the digester. However, the analysis also indicated that if 55% of the heating energy for the digester were supplied by solar power, or if methane production increased by approximately 1.3 times, GHG emissions could be reduced below those of incineration. From an economic perspective, the use of generated methane as an energy source and the reduction of waste‑incineration outsourcing costs are expected to yield savings that exceed operating expenses. Future work should focus on developing scenarios for anaerobic digestion systems that better reflect local conditions, including mechanisms for generating revenue and establishing an operational framework centered on local residents.

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To conserve the habitat of the harvest mouse, Micromys minutus, we conducted a restoration project of Amur silver-grass, Miscanthus sacchariflorus grasslands from 2022 to 2024 at Kizugawa Sports Park in Joyo City, Kyoto Prefecture. Using seeds collected from Amur silver-grass within the park, we created vegetation mats and potted seedlings for transplantation. Jute cloth was used for vegetation mats in 2022, and coir mats were used from 2023 to 2024. Collected seeds were moistened with water while still attached to the ears, stored at 5°C, and after sowing they were grown in a moist condition. Vegetation mats were transplanted in August to September to two conservation areas (Area 1 and Area 2). In 2022, 12 of 14 mats survived (Area 1: 7/7, Area 2: 5/7). All mats transplanted in 2023 died, but in 2024, 2 of 8 mats survived (Area 1: 2/4, Area 2: 0/4). Potted seedlings, transplanted in 2024 to Area 2, had a 30/36 survival rate. In October 2024, a ball-nest of the harvest mouse was built on Amur silver-grass grown from a second-year vegetation mat. The average height of Amur silver-grass from the mats was 161.8 cm, compared to naturally occurring Amur silver-grass. Harvest mice prefer Amur silver-grass over 120 cm for nesting, confirming that second-year transplanted mats achieved sufficient height for nesting.

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