Estimation of bamboo forest distribution in Japan using existing environmental information

Climate change impacts

In recent years a notable expansion of bamboo forests, mainly of the mosōchiku and madake varieties, has been reported throughout Japan, but especially in the west of the country. A decline in biodiversity, increased risk of sediment-related disasters, negative impact on agriculture and forestry, degradation of landscape and decreased carbon sink capacity are considered to be related issues. In Eastern Japan (especially the Tohoku region), where the growth of bamboo forests has until now been relatively slower, global warming as a result of climate change may cause more rapid expansion, and subsequent related hazards.

Adaptation activity

In order to understand the distribution of bamboo forests on a nationwide scale, a study was conducted to estimate the possible distribution areas of bamboo forests throughout Japan using existing bamboo forest distribution data and comprehensive environmental data, and to consider how environmental factors impact the distribution of bamboo. First, using GIS data (see Note 1) on the natural environment, information corresponding to current bamboo distribution was extracted (see Note 2), the data was used to create a 3D mesh model (see Note 3). Statistical analysis based on the data derived from the 3D mesh (see Note 4) and environmental factors (see Note 5) and national land data provided by the Ministry of Land, Infrastructure, Transport and Tourism (see Note 6) was used to determine the probability of bamboo forest distribution for the whole of Japan. Analysis of the 3D mesh model (see Note 7) revealed a broad distribution of bamboo forests, mainly on plains and hilly areas on the western coast of Japan, south of Miyagi Prefecture, and south of Niigata Prefecture on the Japan Sea coast (Fig.). It was also indicated that the probable distribution of bamboo is affected by weather and climatic factors (Warmth Index, annual precipitation, and maximum snow depth). Thess findings suggest an expansion of bamboo forests in new areas, such as northern Japan, due to future global warming.

Outputs / Expected benefits

For areas where the actual state of the distribution of bamboo is not known, by using this model it is possible to more comprehensively predict future growth. The model can also be an effective method for prioritizing which regions need attention, and for developing an overall strategy for limiting further expansion.

Footnote
(Note 1) "Surveys 2-5 of overlapping vegetation"http://www.biodic.go.jp/biodiversity/about/initiatives/index.html
(Note 2) Includes five bamboo varieties: bamboo grove, Phyllostachys edulis (mōsōchiku), mixed Phyllostachys bambusoides (madake) and Phyllostachys nigra var. henonis (hachiku), Phyllostachys bambusoides, Phyllostachys aurea (hoteichiku)
(Note 3) Equivalent to approx.1^km mesh
(Note 4) Generalized Linear Models (Generalized Liner Model: GLMs) analysis
(Note 5) Environmental factors: Warmth Index, annual precipitation, maximum snow depth, surface geology, and slope inclination. Anthropogenic Factors: Percentage of forest, agricultural, and residential land use
(Note 6) National Land Information Division, National Spatial Planning and Regional Policy Bureau, Ministry of Land, Infrastructure, Transport and Tourism http://nlftp.mlit.go.jp/ksj/
(Note 7) Tertiary mesh with bamboo forest distributions of 0.48 or more, which is the threshold obtained by Receiver Operating Characteristic analysis