TORO Nature Center

Introducing Kushiro Marsh Land

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Throughout the four seasons, the unique wetland setting offers a variety of scenes to be experienced.
This natural preserve allows visitors to hear wild songs of birds, see beautiful marsh flowers, and feel the fresh wetland wind.
Let your mind to escape to nature!
Kushiro Marsh Land is the largest marsh in Japan.
This area contains meandering rivers and lakes with a variety of wetland plants such as reeds, sedges, sphagnum, and alders.
The wetland is the habitat for rare species such as Japanese Crane, and Huchen Perri, Siberlan salamander.

Kushiro Marsh Land is designated as Japan’s twenty eighth national park in 1987.
The park has an area of 26,861ha.
About one fourth of the park is specially protected by law, as a specially protected zone making up the core of the wetland.

The climate of the KUSHIRO area has two characteristic features: the low annual average temperature of 5.6C, which causes plants to decompose slowly and form peat; and the annual average of 113 foggy days, 60% of which occur in June, July and August. During this period, only 30% of the potential insulation reaches the earth. Another feature of the climate is the numerous sunny days in early spring, autumn, and winter, and the consequent low annual snowfall.

The most common tree species is
Mizunara (Quercus crispula), and other species include Itaya-kaede (Acer mono var. maarmoratum f. dissectum), Keyama-hannoki (Alnus japonica), Japanese white birch (Betula tauschii var, japonica), Sargent cherry (Prunus sargentii), and Japanese magnolia (Magnolia praecocissima var borealis).

In spring the Sargent cherry and the Japanese magnolia blossoms are very beautiful.
O-kumazasa (Sasa albo-marginata) is abundant on the forest floor, and in some places they severely restrict the growth of young trees.
Along the base of the hills is a transitional vegetation zone where alder and Yachidamo (Fraxinus mandshurica var, japonica) grow among the Yachibozu.

The most representative vegetation zones of the marshes can be seen-low moor, high moor, and an alder forest.Because of the numerous springs and drainage from rivers and streams, the water table of the low moor is always high.
Marsh-reeds (Phragmites) and sedges flourish in the low moor, thus the area is often referred to as reed-sedge marsh.
Depending on soil and water conditions, in some parts of the low moor reeds are dominant and in others sedges are dominant.
Among the sedge group, Mujina suge (Carex lasiocarpa var. occultans) and Tsuru-suge (Carex psuedo c'uraica) arc the most common species; other species include Mitsugashiwa (Menyanthes trifoliata), Kurobanarouge (Potentilla palustris), rabbit-ear iris (Iris laevigata), water hemlock (Cicuta virosa), Karafuto-no-daio (Rumex gmelini), and lobelia (Lobelia sessilifolia).
The Cuckoo Flower (Cardamine pratensis), which in Japan is found only in the marshes of eastern Hokkaido, and the insectivorous bladder wort (Utricularia vulgaris var. japonica) can also be seen.

Rivers and streams do not drain into the high moor, thus its water table is low.
The ground surface is uneven as it is covered with clumps of sphagnum, which is why the high moor is also known as sphagnum bog.
The tops of the sphagnum are far from the water table and are thus quite dry.
This dryness and the cool air are ideal conditions for small shrubs such as Labrador tea (Ledum palustre var. diversipilosum), bog rosemary (Andromeda pollfolia), cranberry (Vaccinium oxycoccus), and crowberrry (Empitrum nigrum), as well as for psychrophytes and alpine plants such as the beard flower (Pogonia japonica), Horomuiso (Scheuchzeria palustris), cotton grass (Eriophorum vaginatum), and round-leaved sundew (Drosera rotundifolia), all of which grow out of the sphagnum.

Alder forest is the only forest type within the Kushiro Marsh Land. Forest in sections of the marshes adjacent to the hills receive nutrients that run off the hills, thus alder in these sections grow to about 10 meters, In the high moor growing conditions are relatively poor, thus alder there only grow to about 5 meters.
In an alder forest it is common to see several alders growing out of one root system, as well as clusters of alder seedlings growing out of dead alder.
At first, alder grow from seeds to the maximum height possible for the growing conditions of a particular site, at which point they die.
From a cluster of alder seedlings growing on a dead alder, a few alders grow to full size.
Growth of this type is called coppice regeneration.