Human response to the drastic environmental changes in Africa

点击翻译按钮获取中文摘要

The dry savanna in Africa have experienced climatic anomalies, with especially high variability of precipitation in the last several decades. Climatic events, such as drought and floods, also have occurred with high frequency. Thus, people living in such regions must have characteristics or indigenous knowledge of the locale in order to cope with environmental changes caused by climatic events. Risk-avoiding or risk-minimizing strategies can be found in land-use systems and structure of living space. This project aimed to establish local geographical maps and local land use maps through field observations and measurements, and to present an analysis of data. The study also includes a discussion of local knowledge on land resource management and subsistence systems. Shinoda continue to measure soil moisture and LAI (Leaf Area Index) of vegetation including pearl millet field, since 1995 for more than 5 years in 3 sites of Niger in order to clarify the climatic change in Sahel. The yearl … More y maximum LAI of millet is no strongly correlated with the amount of annual precipitation. Seasonal increasing trends of LAI were substantially affected by those of soil moisture, especially in the leaf-expanding stage of pearl millet. The present study suggests that the soil moisture during the germination phase does not appear to have a crucial effect on the LAI. Chinen examine the land degradation induced by gullying in tributary drainage basins of the Niger River. By interpreting aerial photographs, development of gullies and land use on a long term were described. Accelerated gully erosion has occurred rapidly on downslopes of glacis and in lower parts of basins, leading to a discharge of an enormous amount of sediments into the Niger River. Takaoka investigated the useful trees in Central Meru District in northern Mt. Kenya. The diversity of utilized indigenous trees does not become higher as humidity increases. A wider variety of indigenous trees are used on the dry, lower slopes than is used on the humid, upper slopes. Hori studies in Mt. Kapushiki area, northern Cameroon and described the situation of population increase and land use, especially farming land. People in the area recognize the land regeneration with people's birth and death, and avoid over-utilizing the land. Less