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Joshin’etsukogen NP, Gunma
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At 2,150 m, Yoshigadaira is the world’s highest recorded breeding site for the Japanese forest green tree frog. Here, it lays its foamy eggs on waterside grasses, not the overhanging branches it usually chooses.
At the wetland group’s Chatsubomigoke area, the liverwort and iron bacteria help generate iron ore. Carbon in the ore dates back more than 10,000 years, and fossils and bacterial traces suggest this process has persisted for millennia.
The wetland group’s lower Chatsubomigoke area was once a bustling mining community: more than 2,000 people lived there, including about 300 children. The mine town had a theater, shop, movie screenings and sports events.
At Anajigoku, water with a pH of 2.6–2.8 stays warm even in winter, nurturing East Asia’s largest known colony of the acid-loving aquatic liverwort Jungermannia vulcanicola.
Yugama, the emerald crater lake within the wetland group, has a pH of just 1.0–1.2. Its extreme acidity leaves little vegetation around the lake—a striking contrast with the lively wetlands lower down.
Yoshigadaira is a 887-hectare chain, not one single bog: its volcanic landscape steps from about 2,160 m down to 1,200 m, linking moors, ponds, a crater lake and streams.
Below the open moors, the forest hides 3 natural ponds—Heibee-ike, O-ike and Mizu-ike. Aquatic plants, including Isoetes asiatica and Potamogeton fryeri, grow in these tucked-away waters.
