Effects of Connectivity between Forest and Paddy Levees on Soil Animals in Satoyama

Abstract

We investigated the influence of different levels of connectivity between forest and paddy levees on soil animals and nutrient cycles in satoyama. Three study sites were selected on Sado Island, central Japan, each of which has experienced different modifications in the transitional zone between forest and paddy levees. Twelve belt transects were set from the forest to paddy levee. In each belt transect, we collected soil animals and measured the organic matter decomposition rate. Collected soil animals were classified based on different guilds and compared between study sites. The result indicated some differences in the functional group composition of soil animals and organic matter decomposition rate in the forest and paddy levees among the study sites. At the site with high landscape connectivity, high amount of litter and high organic matter decomposition rate were observed at the forest edge. On the other hand, at the site with low landscape connectivity, relatively low densities of predator, relatively high densities of decomposers and shredders, and high organic decomposition rate were observed at paddy levees. Thus, the results suggest that even when a forest and agricultural land are adjacent to each other, the ecological function of the forest edge differs owing to differences in landscape connectivity.