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S.F. Chen et al. 2010. A physiotope-based model for ecoregions for the the nationwide ecosystem management of Japan
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the exceedingly high mean proximity index of the Tertiary Mountains and Hills class thus
making it the most connected single patch of all regions (Fig. 2e).
Analysis on the landscape level shows strong patch size heterogeneity and strongest
connectivity among all regions (Table 1).
3.1.4 Region D – Hokkaido
Interestingly, the land percentage of all physiotope classes in Hokkaido is almost similar to NE
Japan, the only difference being the absence of Mesozoic Granite Mountains in Hokkaido.
Hokkaido is characterized by fragmented coarse grain size with relatively low connectivity
which is distributed unevenly across the region, particularly Paleozoic-Mesozoic Mountains and
Tertiary Mountains and Hills (Fig. 2a-2f).
Analysis on a landscape level shows that this region has the biggest mean patch size, lowest
patch size heterogeneity, very low connectivity and most fragmented patches (Table 1).
4. Discussion
Landscape compostion of physiotope classes among the geological regions vary. Inner Zone of
SW Japan consists of older terranes, volcanic landforms and the highest percentage of Mesozoic
granite rocks formed around 150 million years ago. Both NE Japan and Hokkaido consist
mainly of newer terranes of Tertiary mountains (formed around 20 million years ago) and
Quaternary terranes (Fig. 2a). Jurassic accretionary prisms occupied the largest area of the pre-
Neogene basement rock of SW Japan when igneous activity and regional metamorphism was
most intensive. But during the Neogene era, Neogene sedimentary basins were formed only in
certain parts of SW Japan while the entire of NE Japan and Hokkaido were covered with
Neogene strata. During the Pleistocene-Holocene period, uppermost Pleistocene and Holocene
strata formed extensive Quaternary plains in NE Japan and Hokkaido, while forming a majority
of small and narrow plains in SW Japan (Kimura, Hayami & Yoshida 1991). The late
Quaternary was also characterized by major changes in species distribution and composition of
biotic communities (Delcourt & Delcourt 1988).The Outer Zone of SW Japan is unique both in
landscape composition and configuration, being dominated by Paleozoic-Mesozoic Mountains.
In terms of physiotope class configuration, Inner Zone of SW Japan has the most complicated
mosaic with small, non-contiguous, independent patches distributed all across the region. NE
Japan is unique, characterized by a large, continuous patch of Tertiary Mountain and Hills class
type on the Japan Sea side and a solitary Quaternary Plain with Volcanic Ash Soil in the Kanto
plains (Fig. 2b-2f). Complexity of landscape mosaics can be linked to the habitat types formed
within. The dominant Tertiary mountains and hills patch of NE Japan coincide with the Fagus
crenatae (broad-leaved deciduous forest) region's extent (MOE, 1989). Quaternary Plains with
volcanic ash soil class type is unique because they are situated next to volcanic regions which
supply the debris and being soil originating from tephra, it is among the most productive soil in
the world (Shoki & Takahashi, 2002).
The ecologically applicability of the results lies in ecoregion delineation of Japan. The 12
climate-influenced ecoregions nested in each geological region display the significance of the
Japan Sea, Okhotsk Sea and the Pacific Ocean's influences on each unit and act as the main
controlling factor over the physiotope regions (Fig. 1). Even though defining the ecoregions for
Japan is not an easy task and will require more extensive study, this physiotope model of
ecoregions has potential as a basemap used in conjunction with environmental databases for
further refinement of this study and for other research and management purposes.
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.