A high biodiversity had been found in the past “Satoyama”, because of its mosaic distribution of woodland and grassland. But now, bio-diversity in Satoyama has been deteriorated by changed environment by stopping management. Few studies have been, however, reported the effect of such change of Satoyama on forest biota. Present study intends to clarify the relation between moths and forest environment.

The study areas were 12 sites from 3 forests in Otsu, Shiga Prefecture Japan. The moths were collected ten times by light trap in all sites during April - November, 2009 and April - October, 2010. The vegetation survey was carried out in 50m × 50m quadrat in each site.

Moth of 31 families 649 species 16291 individual were sampled. Number of species showed a negative correlation with the openness of tree coverage and its deviation. Number of individuals had a negative correlation with the openness of tree coverage and its deviation, also with grassland area and its deviation.

It is said that the forest fauna is diverse when with a higher environmental heterogeneity such as the patchness of open space. However, the present results are inconsistent with this idea. Therefore, for the conservation of biodiversity in the Satoyama, more careful studies are necessary to understand the environmental demand of respective animal group.