National Institute for Agro-Environmental Sciences, Tsukuba, Japan.
The Museum of Nature and Human Activities, Hyogo, Japan.
Sci Total Environ. 2016 Jan 15;542(Pt A):478-83. doi: 10.1016/j.scitotenv.2015.10.067. Epub 2015 Nov 3.
An understanding of land-use change and its drivers in agroecosystems is important when developing adaptations to future environmental and socioeconomic pressures. Agricultural abandonment occurs worldwide with multiple potentially positive and negative consequences; however, the main factors causing agricultural abandonment in a country i.e., at the macro scale, have not been identified. We hypothesized that socio-environmental factors driving agricultural abandonment could be summarized comprehensively into two, namely "natural" and "social", and the relative importance of these differs among regions. To test this postulate, we analyzed the factors currently leading to agricultural abandonment considering ten natural environment variables (e.g., temperature) and five social variables (e.g., number of farmers) using the random forest machine learning method after dividing Japan into eight regions. Our results showed that agricultural abandonment was driven by various socio-environmental factors, and the main factors leading to agricultural abandonment differed among regions, especially in Hokkaido in northern Japan. Hokkaido has a relatively large area of concentrated farmland, and abandonment might have resulted from the effectiveness of cultivation under specific climate factors, whereas the other regions have relatively small areas of farmland with many elderly part-time farmers. In such regions, abandonment might have been caused by the decreasing numbers of potential farmers. Thus, two different drivers of agricultural abandonment were found: inefficient cultivation and decreasing numbers of farmers. Therefore, agricultural abandonment cannot be prevented by adopting a single method or policy. Agricultural abandonment is a significant problem not only for food production but also for several ecosystem services. Governments and decision-makers should develop effective strategies to prevent further abandonment to ensure sustainable future management of agro-ecosystems.
了解农业生态系统中的土地利用变化及其驱动因素对于应对未来环境和社会经济压力的适应措施至关重要。农业弃耕现象在全球范围内普遍存在，其带来的后果可能是多方面的，既有积极的，也有消极的；然而，导致一个国家（即宏观层面）农业弃耕的主要因素尚未确定。我们假设，导致农业弃耕的社会环境因素可以概括为两类，即“自然”和“社会”，而这两类因素在不同地区的相对重要性也有所不同。为了验证这一假设，我们使用随机森林机器学习方法，在将日本分为八个区域后，分析了目前导致农业弃耕的因素，这些因素考虑了十个自然环境变量（如温度）和五个社会变量（如农民数量）。结果表明，农业弃耕是由各种社会环境因素驱动的，导致农业弃耕的主要因素在不同地区存在差异，尤其是在日本北部的北海道。北海道拥有相对集中的大面积农田，弃耕可能是由于特定气候因素下的耕作效率提高所致，而其他地区的农田面积相对较小，且有许多兼职的老年农民。在这些地区，弃耕可能是由于潜在农民数量的减少所致。因此，我们发现了两种不同的农业弃耕驱动因素：耕作效率低下和农民数量减少。因此，不能通过采用单一方法或政策来防止农业弃耕。农业弃耕不仅对粮食生产，而且对许多生态系统服务都是一个重大问题。政府和决策者应制定有效的战略来防止进一步的弃耕，以确保未来农业生态系统的可持续管理。
