Effects of fragmentation of secondary broadleaf deciduous forests on populations of the near‐threatened butterfly,Sasakia charonda(Lepidoptera, Nymphalidae), in central Japan

Abstract

AbstractWe examined the effects of fragmentation of secondary broadleaf deciduous forests (secondary forests) on populations of the near‐threatened butterfly,Sasakia charonda, in central Japan. Regression analyses revealed that the number of overwintering larvae per host tree significantly increased when the area of secondary forest patches and the Isolation Index of the forest patch increased and the distance from secondary forest patches containing the focal host trees to the nearest secondary forest patch decreased. There was a significantly positive correlation between the number of overwintering larvae and the number of host trees in the neighborhood. The host trees were primarily distributed at the edges of secondary forests. From the results of the backward elimination method of multiple linear regression analysis, independent variables other than patch area were eliminated, and the standardized partial regression coefficient of the patch area was significant. This result suggested that a contiguous distribution of large secondary forest patches with many host trees is very important to conserving this butterfly species.