The ecology of this park can be roughly classified into three types: wilderness with volcanic gas fumes; forests covering the mountain base; and grassland maintained by controlled burning and mowing. Plants such as Rhododendron kiusianum and cowberry grow in clusters around the volcano. Many endangered plants grow in the grasslands, such as Echinops setifer and Viola orientalis.
Endangered butterflies such as the Shijimi large blue (Shijimiaeoides divinus), and insects such as the Kyushu-ezozemi cicada and Daikoku-kogane scarab beetle live in the park's forests and on its grasslands. Birds here include the meadow bunting, chestnut-eared bunting, Japanese reed bunting and black-browed reed warbler.