Human Response to Climatic Events in the Dry Savanna, Africa

在肯尼亚、尼日尔和贝宁进行了野外调查，以记录非洲干旱草原地区人类对气候变化的响应特征，并对肯尼亚山东北麓梅鲁地区的树木利用进行了地理和历史调查。在南部潮湿地区，梅鲁人使用一些树种，他们对树木的传统用途有更多的了解。新定居在北方干旱地区的人使用的物种较少，知识稍差。干旱的战略，但是，他们在干旱地区的shambas使用树木和灌木的方式，包括在北方肯尼亚的马尔萨比特区的环境变化和养牛的社会文化概况之间的生态联系进行了研究。Samburu人有自己的风险规避系统，并在过去的严重干旱中幸存下来。在过去的40年里，在尼日尔西南部的尼日尔的支流流域重建了被侵蚀的景观。在过去的20年里，由于周围地区的森林砍伐，土壤侵蚀加速了。土地退化导致农田缺乏，并破坏了尼日尔河沿岸的渔业。为了弄清最近气候变化的趋势和大气与地表的相互作用，对尼日尔和贝宁沿着干旱地区（萨赫勒）和湿润地区（几内亚海岸）的气象资料进行了分析，并观测了土壤湿度。在雨季，由于降雨间隔时间缩短，土壤湿度不断增加。不同年降水量的3个观测点在旱季的土壤含水量差异不显著。观察到的湿度范围从1%到5%的季节。

Field researches were conducted in Kenya, Niger and Benin to document the characteristics of human response to climatic change in dry savanna areas, Africa.Geography and history of tree utilization were investigated in Meru District extending on a northeastern foot slope of Mt.Kenya. In southern humid areas, Meru people used a number of tree species and they had more knowledge on traditional uses of trees. People newly settled in northern dry areas used less species and had slightly poor knowledge. Strategies for droughts, however, were included in the ways in which they use trees and shrubs in their shambas in dry areas.An ecological linkage between environmental changes and socio-cultural profile of cattle keepers were studied in Marsabit Distrct, northern Kenya. Samburu people had their own risk-avoiding systems, and survived the past severe droughts.Development of eroded landscapes during the last 40 years was reconstructed in tributary drainage basins of the Niger, southwestern Niger. Soil erosion had been accelerated for the past 20 yesrs owing to deforestation in the surrouding area. The land degradation caused lack of crop fields and damaged fishery alog the Niger River. They were bewildered by the emerged environmental problems and started talking measures to cope with the situation.To clarify the recent trend in climatic change and the interaction between atmosphere and land surface, collected meteorological data were analyzed and soil moisture were observed in Niger and Benin along a cross section from arid region (Sahel) to humid region (Guinean coast). Soil moisture incresed continuously during rainy seasons owing to reduced rainfall intervals. No significant difference in soil moisture was detected in dry seasons among three observation sites with different annual precipitation. The observed moisture ranged from 1 to 5 percent in the seasons.