Hibuna and Artificial Water Plants in Lake Harukata - Crisis and Restoration of Lake Harukata in Kushiro City (1980s-2000s)

Hibuna and Artificial Water Plants in Lake Harukata - Crisis and Restoration of Lake Harukata in Kushiro City (1980s-2000s)
Lake Harumikari, located adjacent to the urban area of Kushiro City, was once called the "Pearl of the Plateau," and was designated as a national natural monument in 1937 as a habitat for hibuna (Hypsipetes hibensis). In 1937, it was designated as a national natural monument as a habitat for hibuna. However, the water quality rapidly deteriorated due to the inflow of domestic wastewater caused by urbanization since the 1980s. In addition, the waterweed community was almost completely destroyed in less than 20 years by the invasive alien species, Uchida crayfish, which began feeding on the waterweeds around 2000.
In response to this crisis, Kushiro City Museum started an effort to artificially restore spawning cradles by installing artificial waterweeds at the bottom of the lake. Artificial plants were introduced on an experimental basis in the mid-2000s, and many eggs were laid, confirming the success of the project. This was a practical emergency measure to restore the ecosystem in parallel with the extermination of non-native species.
In recent years, it has been reported that the waterweed community has begun to recover slightly and the spawning grounds are returning to their natural state, thanks to years of extermination efforts. The fact that eggs are now attached to artificial waterweeds is an important sign that the local population, which was on the brink of extinction, has begun to regenerate, and indicates that this small lake left in Kushiro is regaining its vitality.