The Kaga Coast (Japan): A Natural Ecosystem and Cultural Landscape Ensuring Biodiversity

Abstract

The Kaga Coast, along the Sea of Japan, has highly diverse ecosystems involving natural and anthropogenic landscapes. The most natural area is old Kashima island, with a Shintō shrine; it is connected to the main island and is a National Natural Monument of Japan. Persea thunbergii forest remains under protection and is the habitat of a terrestrial crab (akate-gani: Chiromantes haematocheir). The crabs live in the forest, eat evergreen leaves, and hibernate in burrows. The scene of akate-gani egg-laying is a good example of a food chain, and the Persea forest seems like a terrestrial mangrove forest holding the habitat of crabs. The long (16.4 km), high (46 m) sand dune along the Kaga Coast has been managed since 1766, by plantation of black pine (Pinus thunbergii) on the back dune and Vitex rotundifolia on the foredune. Nowadays the planted Pinus thunbergii forests and sand-dune vegetation protect human lives and also restore and support biodiversity. Even though people planted Pinus thunbergii, it still continues nowadays and creates a unique landscape. First, as a planting for defense against mobile sand, the local people combined traditional Japanese technology with European (e.g. French) technology to make the planting succeed. Actually, the method of making artificial foredunes and planting coastal plants was invented independently in Edo-era Japan and in Europe. In Japan, they used dune herbs like Carex kobomugi, Calystegia soldanella etc. and shrubs like Vitex rotundifolia. On the back dune they planted mainly black-pine trees to protect farms and villages from being buried by sand blown by winter winds. They gained partial, temporary results, but could not get a final solution. On the Kaga Coast, it is confirmed that there are 17 kinds of animals and over 290 kinds of birds (including Nipponia nippon). There are 18 kinds of “important species,” as designated in the Red Data Book of Japan and of Ishikawa prefecture. Insects utilize both shrubs and herbs, which also represented technological progress in the planting project. This technology and experience was highly significant for sand-defense forests in Japan. The Kaga Coast can thus be described as an area where the human landscape and biodiversity are in harmony.