Causes and dynamics of vegetation change in Mato Grosso State, Brazil

三重大学大学院生物資源学研究科博士後期課程共生環境学専攻Mato Grosso has emerged as the Brazilian state with the highest deforestation rate, and with the most dynamic changes in vegetation and land covers. In this paper, we focused on the fallowing two main objectives: (i) to quantitatively assess the extent of vegetation change over the past two decades for more accurate eco-climatic impact analysis, and (ii) to clarify the causes to these changes, with special focus to human factors, in Mato Grosso as our case study. 5-year Digital Vegetation Model (DVM) Maps between Phases I and IV were created for every five years during the 1981-2001 period using the first components of the principal components analysis (PCA) of NOAA/AVHRR multi-spectral data (Channels 1, 2 and 4). Vegetation and land cover changes are characterized by destruction of primary forests in the north and large-scale human activity and savanna areas expanding from the south. Large-scale soybean production spreading over the central areas and vast herds of cattle in the north can be pointed to as the main causes to vegetation change in these areas. In Chapter 2, we suggest that 76.1 % (89.5 %) of the changes in land cover types occur within 30 km from paved and unpaved roads (roads and navigable rivers). This emphasizes not only the role of road building, but also that of navigable rivers, in accelerating deforestation, especially over the sparsely populated and road less north. In Chapter 3, we have the following three specific objectives to do more detailed analysis for cause of deforestation and savanization in particular these areas using agriculture and cattle ranching industry data at municipal districts levels. We clarified how there were the vegetation change 3 category of Degradation, Recovery and Transitional area with5-year DVM vegetation change map I-II, II-III, III-IV and I-IV About 46 % of MT area was deforestation degradation during 1981-2001 (Recovery areas are almost non-existant 0.9 %), and it developed that the cause depended on an advance of cattle ranching and Corn production in northern part, Soybean and Sugarcane production in central and west MT and much agriculture and cattle business in southern part of MT using GIS and remote sensing data. We suggest clearly cause of deforestation and savannization in each municipal districts. Most of deforestation in tropical rainforests is caused by cattle ranchers or corn farm land in northwest MT and soybean or sugarcane farm land in central MT. And savannization by soybean and sugarcane farm land spread mainly in the west MT and by corn in the southwest. Corn productions have more savannization impacts than the soybean crop production. In Chapter 4, change rates are shown to be larger over non-inhabited areas (56 %) than over the populated zones in the south (42 %). All these findings denote the non-sustainable processes of resource development occurring in MT, mostly for needs of developed countries. For our stomachs and life of the developed country, most of treasured and valuable vegetation change and destroy. We pray that these and conventional studies will be with the decision making about the future of the Brazilian country when, in addition, our earth