Although natural disturbances are inherent in any ecosystem, they can be hazardous to the local residents, indicating that it is necessary to mitigate these disturbances as much as possible appropriately. There has been an increased interest in taking advantage of ecosystem functions for disaster risk reduction (Eco-DRR) as future infrastructure because of the lower introduction, maintenance costs, and the additional ecosystem services. Previous studies have suggested that intact ecosystems have a higher tolerance and/or resilience to natural disturbances. However, fully intact ecosystems have been decreasing rapidly worldwide. This study evaluates the functions of semi-natural land, namely, paddy fields, which is one of the typical agricultural land uses of monsoon Asia to reduce the societal damages of natural disasters. As semi-natural land is sometimes located close to or is similar to the original intact habitat, it could play a role in reducing flood disasters. In particular, paddy fields could be seen to be similar to intact wetland habitats, most of which have disappeared in recent decades due to development. To test this idea, the relationships between flood disasters and paddy fields with location condition in inland regions of central Japan were evaluated. We used flow accumulation value (FAV) as an index of intact wetland habitat; particularly, we considered that high FAV area might be previously natural wetland. Thus, paddy field located at high FAV values are considered similar to intact wetland habitats. Results showed that paddy fields located in high FAV areas were able to significantly reduce flood frequencies, occurrences of landslides, and debris floods. These results suggested that semi-natural land close to or on their natural habitats could function as intact ecosystems and provide Eco-DRR function as ecosystem services. These types of semi-natural land could be employed as green infrastructure to provide several extensive ecosystem services.

尽管自然干扰是任何生态系统中固有的，但它们可能对当地居民造成危害，这表明有必要尽可能适当地减轻这些干扰。由于较低的引入，维护成本和附加的生态系统服务，人们越来越有兴趣利用生态系统功能来减少灾害风险（Eco-DRR）作为未来的基础设施。先前的研究表明，完整的生态系统对自然干扰具有较高的耐受性和/或弹性。但是，全球范围内完整的生态系统正在迅速减少。这项研究评估了半自然土地的功能，即稻田，这是季风亚洲减少农业自然灾害的典型农地用途之一。由于半自然土地有时靠近或类似于原始的完整栖息地，因此它可以在减少洪水灾害中发挥作用。特别是，稻田可被视为与完整的湿地栖息地相似，由于发展，其中大多数在最近几十年中消失了。为了验证这一想法，评估了日本中部内陆地区洪水灾害与稻田之间的关系。我们使用流量累积值（FAV）作为完整湿地栖息地的指标；特别是，我们认为高FAV面积可能是以前的天然湿地。因此，位于高FAV值的稻田被认为与完整的湿地生境相似。结果表明，位于高FAV区域的稻田能够显着减少洪水发生的频率，发生滑坡，和碎片洪水。这些结果表明，接近或位于其自然栖息地的半自然土地可以作为完整的生态系统发挥作用，并提供Eco-DRR功能作为生态系统服务。这些类型的半自然土地可用作绿色基础设施，以提供多种广泛的生态系统服务。