2022 Volume 28 Pages 41-56
The concept of green infrastructure in Japan entails the utilization of diverse functions of the natural environment for creating sustainable and attractive national land. However, despite the increasing pressures of an aging population and population decline, the means to accomplish these goals with respect to the above challenges are not entirely clear. The Aso region of Japan, located in the center of Kyushu Island, is known for its vast area of semi-natural grasslands, which has been decreasing rapidly in the past decades due to agricultural modernization and lifestyle changes. The aging workforce and the lack of new entrants into the labor pool have given rise to additional pressures, making it difficult for local communities to continue to conduct annual grassland management such as controlled burning and fire-belt making. This research paper aims to identify thresholds of grassland management in terms of the labor force using responses from a community survey conducted in 2016, on the understanding that the existence of grasslands and their functions is dependent on the continuation of human activities. With regard to fire-belt making, the average age of local participants and the length of mowing per person were the factors that contributed to making the situation difficult. Sixty meters per person has been identified as the threshold or the maximum durable length of mowing. For controlled burning, the number of local participants and their age structure were the main determinants. There was no obvious threshold found for the area of burning per person, but it may be wise to use two hectors per person as a rule of thumb. Volunteers contributed substantially to lowering the amount of work necessary for controlled burning and fire-belt making. This paper is one of the few to address the importance of underlying communities in maintaining the semi-natural grassland ecosystem and to make suggestions for management support and/or measures based on the identified thresholds.
