Abstract
Considering conservation measures for Lefua echigonia populations inhabiting planned areas of the development project in valley-bottom paddy fields in two river basins of midwestern Aichi Prefecture in Japan, the genetic diversity was analyzed for seven sites in this region and one site in another region using their mitochondrial DNA (mtDNA) D-loop and microsatellite DNA. All specimens were found to have the same sequence among seven sites, and they belonged to the previously known populations identified in the Tokai region. Microsatellite analysis revealed that each site was genetically coherent for each river basin, and there was a difference in the degree of genetic divergence between the two river basins in the same water system based on the calculated genetic differentiation (FST) and STRUCTURE analysis. One site affected by the project and another neighboring site had very low genetic diversity and middle-range genetic divergence was observed between them. However, it was due to fragmentation and miniaturization of the habitat caused by the paddy field development, and these two sites were identified as belonging to the same genetic group. Therefore, it is considered effective to ensure habitat and genetic exchange by treating both sites as one.
