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Plant Formations in the Sakhalin-Hokkaido BioProvince
Peter Martin Rhind
Sakhalin-Hokkaido Conifer Forest
These forests are mainly confined to the montane areas in the south but further north go
down to sea level. The three main trees include the endemic Abies sachalinense and
Picea jezoensis, the near endemic Picea gledhnii (Pinaceae), but these may be intermixed
with Betula ermanii and B. maximowicziana. The shrub layer may include Acer
ukurunduense, Euonymus macropteris, Vaccinium smallii and the endemic Ribes
sachalinense (Grossulariaceae), while the herb layer species include Cornus canadensis,
Tiarella polyphylla, Maianthemum bifolium, Streptopus streptpoides, Trillium tschonoskii,
and ferns and fern allies such as Rumohra mutica and Lycopodium serratum var.
thunbergii. In certain dry habitats such as on volcanic soil, rocky or gravel ridges and
slopes, or in the serpentine areas, as well as in certain wet habitats such as fens, swamps
or marshes, Picea gledhnii usually forms the main tree species. In the sparse early stages
of P. gledhnii forest on serpentine habitats the associated species characteristically
include Berberis amurensis and the endemic Crepis gymnopus (Asteraceae), while the
later stages often have dense undergrowth of the near endemic broad-leaved bamboo
Sasa kurilensis (Poaceae). On the rock or gravel slopes, the forest floor is usually
dominated by Menziesia pentandra, Rhododendron brachycarpum (R. fauriei) or the
endemic Carex sachalinensis (Cyperaceae). Wetland P. gledhnii forests are also have
varied composition, but species such as Carex middendorfii, Lysichiton camtschatense,
Moliniopsis japanica or Osmunda asiatica may dominate the forest floor.
Sakhalin-Hokkaido Volcanic Vegetation
Because new surfaces are constantly being created on active volcanoes, they are very
important to plant ecology especially in the study of plant succession. In this BioProvince
ecological studies have been carried out on volcanoes such as Komagatake, Kousu and
Ousu in Hokkaido. Some 20 years after volcanic activity on Ousu, a tall herb community
including Ixeria japonica, Miscanthes sinensis, Oenotherea biennis, and the endemic Aster
glehni (Asteraceae) had developed in the unstable accumulations of ash, soil and debris,
whereas in the more stable areas a pioneer forest of Betula platyphylla var. japonica, B.
ermanii, Populus maximowiczia and the endemic Salix sachalinensis (Salicaceae) had
become established.
Sakhalin-Hokkaido Fens and Bogs
On Hokkaido’s Kushiro and Sarabetsu moors, two types of reed (Phragmites communis)
fen have been identified. One is co-dominated by Carex miyabei and in the other by the
endemic Carex augustinowiczii (Cyperaceae). The latter forms extensive tussocks often
inhabited by Adenophora triphylla var. tetraphylla, Artemisia vulgaris var. kamtschatica and
the fern Thelypteris palustris, while Calamagrostis langsdorffii, Hosta rectifolia,
Sanguisorba tenuifolia var. alba, and the near endemic Solidago virgo-aurea var.
yezoensis (Asteraceae) occur between the tussocks. With increasing development of acid
peat, the near endemic grass Moliniopsis japonica (Poaceae) becomes the dominant
species. This species has similar ecological requirements to Europe’s Molinia caerulea.
Associated species include Eleocharis japonica, Pogonia japonica and the fern Osmunda
cinnamomea.
Sakhalin-Hokkaido Alpine Grasslands
In the snow bed grasslands a number of communities have been described including ones
co-dominated by the Phyllodoce aleutica and the endemic Salix yezoalpina (Salicaceae),
Copyright © 2010 Peter Martin Rhind
while on Mount Rishiri these grasslands are occasionally dominated by the endemic
Papaver fauriei (Papaveraceae). Other Rishiri endemics include Cortusa matthiola var.
congesta (Primulaceae), Oxytropis rishiriensis (Fabaceae) and Trollius pulcher
(Ranunculaceae). The so-called windward grasslands are mainly free of snow due to
exposure to strong winds, which also have a desiccating effect. These areas are typically
characterized by an abundance of leguminous species especially of the genus Oxytropis
(Fabaceae), and regional speciation of this genus is a feature of the BioProvince. Some of
the regional dominants include the endemic O. shokanbetsuensis on Mount Shokanbetsu,
the endemic O. kodoana on Mount Hidaka and the endemic O. magalantha on Rubun
Island. Other characteristic species of these grasslands include Bupleurum triradiatum,
Minuartia arctica, Patrina sibirica, and the endemic Saxifraga nishidae (Saxifagaceae).
Sakhalin-Hokkaido Alpine Deserts
At high altitudes in volcanic areas, repeated accumulation of volcanic ejecta, short growing
seasons and long lasting snowdrifts have created expanses of open vegetation. Two of
the most characteristic species of these barren volcanic regions are Dicentra peregrina
and Viola crassa. In the serpentinitic areas, these alpine deserts are characterized by high
levels of endemism. For example, on Mount Apoi (Hokkaido) endemic species such as
Cirsium apoiense, Erigeron thunbergii var. angustifolius, Hypochoeris crepidioides,
Saussurea reideri var. yezoensis (Asteraceae), Primula hidakana (Primulaceae),
Bupleurum nipponicum var. yezoense (Apiaceae), Viola hidakana (Violaceae), Hypericum
samaniense (Hypericaceae), Aruncus dioicus var. subrotundus (Rosaceae),
Callianthemum miyabeanum (Ranunculaceae), Arenaria katoana var. lanceolata
(Caryophyllaceae), Betula apoiensis (Betaceae), Tofieldia coccinea var. kondoi
(Tofieldiaceae), Allium schoenoprasum var. yezomonticola (family) occur, while on Mount
Yubari (Hokkaido) the endemics include Lagotis glauca var. takedana (Plantaginaceae),
Primula yuparensis (Primulaceae) and Viola yupariana (Violaceae). The dominant species
in these serpentinitic alpine deserts include the endemic Arenaria katoana var. lanceolata
(Caryophyllaceae) on Mount Apoi, the endemic Viola yupariana (Violaceae) at the centre
on snow patches on Mount Yubari, and the endemic Saussurea chionophyllum
(Asteraceae) forms the dominant species of associations found on Mount Apoi, Mount
Tottabetsu and Mount Yubari.
Sakhalin-Hokkaido Vegetation of Coastal Cliffs and Scree
The sea cliffs of northern and western Hokkaido are known for their abundance of alpine
and boreal species at low altitudes. These include Cochlearia oblongifolia, Dianthus
superbus, Juniperus chinensis var. sargentii, Sedum ishidae, Trifolium lupinaster, the near
endemic Draba borealis (Brassicaceae) and the endemic Primula modesta var.
matsumurae (Primulaceae). At the foot of these cliffs, maritime screes occur supporting
species such as Lathyrus maritimus and Lotus corniculatus var. japonicus in the less
stabile areas, but with increasing stability these give way to a tall-herb community with
species like Artemisia montana, Filipendula kamtschatica, Urtica platyphylla, Cacalia
hastata var. orientalis, together with endemics such as Petasites japonicus var. giganteus
(Asteraceae) and Polygonum sachalinensis (Polygonaceae).
Sakhalin-Hokkaido Saltmarsh
Like many northern saltmarshes, Salicornia europaea (aggregate) forms the main pioneer
taxon, but here a belt of Spergularia marina landward of the pioneer zone also
characterizes these marshes. Further inland the common species include Glaux maritima
var. obtusifolia, Triglochin maritima and Potentilla egedeii var. groenlandica, while in the
sub-arctic saltmarshes of eastern Hokkaido the endemic or near endemic Carex
ramenskii, C. subspathacea (Cyperaceae) and Puccinellia kurilensis (Poaceae) occur.
Copyright © 2010 Peter Martin Rhind
Sakhalin-Hokkaido Sand Dune Vegetation
As with dunes throughout Japan, the mobile areas are dominate by Carex kobomugi,
Elymus mollis, Glechnia littoralis, Ischaemum anthephoroides, Ixeris repens, Lathyrus
maritimus and Zoysia macrostachys, but in addition, the norther mobile dunes of Hokkaido
are characterized by Carex macrocephala and the near endemic Linaria japanica
(Scrophulariaceae). Fixed dunes typically include scrub often dominated by Rosa rugosa,
while interspersed among the scrub and occasional grassland are various flowering plants
such as Lilium maculatum var. dauricum, Thermopsis lupinoides and the endemic
Hemerocallis yezoensis (Hemerocallidaceae). Quercus dentata is usually the main tree
species found on fixed dunes, but may be associated with a sparse covering of other trees
including the endemic Salix bakko (Salicaceae).
References
Kanai, H. 1963. Phytogeographical observations on the Japano-Himalayan Elements.
Journal of the Faculty of Science, University of Tokyo, Sect 3. Botany, 8: 305-339.
Kolbek, J., Srutek, M. & Box, E. O. 2003. Forest Vegetation in Northeast Asia. Kluwer
Academic Publishers.
Numata, M. (ed). 1974. The flora and vegetation of Japan. Elsevier Scientific Publishing
Company.
Numata, M., Miyawaki, A. & Itow D. 1972. Natural and semi-natural vegetation in Japan.
Blumea, 20: 435-481.
Satoo, T. 1983. Temperate broad-leaved evergreen forests of Japan. In: Ecosystems of
the World 10 - Temperate Broad-Leaved Evergreen Forests. Elsevier.
Copyright © 2010 Peter Martin Rhind