Comparative characterization of soil mesofauna diversity of the 'satoyama' ecosystem on the Nara campus, Kinki University, Japan, Padang, Sumatra, Indonesia, and Adugyama, Kumasi, Chana

'Satoyama' is a Japanese word. 'Sato' means the habitat of village people, and 'yama' means forested mountains. Therefore, satoyama is composed of watersheds, which includes forested mountains, upland farms, and lowland rice fields as well as irrigation canals and ponds. Satoyama watersheds have been subject to human development, management, and intervention. They are composed of various land use systems. Here we defined the Japanese satoyama as 'temperate', those in Indonesian as 'super wet tropical', and those in Ghana as 'seasonally wet and dry tropical'. The differences among these ecological environments are big in terms of temperatures, hydrology, vegetation, and other natural characteristics. The objectives of this study were to compare the diversity of soil mesofauna in three satoyama systems in Japan, Sumatra, and Ghana. We collected 400 cc of topsoil includes litter layers for soil animal extraction using Tullgren equipment. The vertical depth was 0 to 4 cm, and in Japan and Indonesia we also took soil at 4 to 8 cm. Soil mesofauna act as decomposers of litter falls, so they are important for forest ecosystem to supply nutrients to the soils and plants as well as to form soil humus and structure. The summary of our findings is as follows. Acari were the largest populations in all three countries, while population sizes of collembola varied. In Japan, collembolas were the second-largest group, while there were few collembolas in Ghana, where there were many Hemiptera. The greatest number of population of mesofauna was found in Indonesia, followed by Japan and finally Ghana. Regarding the numbers of soil mesofauna classes and orders, they were the highest in Indonesia, followed by Ghana and then Japan. We confirmed that the tropical zone was superior to the temperate zone with regard to biodiversity. The population composition ratio of soil mesofauna, except for Acari and Collembola, varied among the countries. For example, Coccoidea (order Hemiptera) were especially numerous in Indonesia and Ghana. The total population was negatively related with bulk density, that is, it was positively related with pore space and habitat space. This was the case in all three countries. However, there was no linear relationship between soil fertility (chemical characteristics) and soil bulk density (physical characteristics) and diversity of soil mesofauna.