Abstract
The relationships between habitat partitioning and the patterns of species diversity of collembolan families in relation to horizontal and to soil depth distributions have not been understood yet. The relationships between soil depth distribution and alpha diversity within a forest stand or beta diversity among forest stands in Simpson's diversity index for 9 family groups of soil Collembola were studied in 6 natural broad-leaved forests and 5 larch plantations of cool temperate zone in northern Japan. Studied forests were on wide range of environmental gradients including two forest types, deciduous broad-leaved natural forests and larch plantation, on south and north facing slopes, and from upper ridge to bottom of the slopes. Collembolan species were classified into 9 family groups. The percentages of organic layer dwellers to total abundance for a family group (%OL) of Tomoceridae, Entomobryidae, Neelidae and Sminthroidea were significantly higher than the other families. The standard deviation of weighted mean of %OL (SDW) of Isotomidae and Onychiuridae/Tullbergiidae were significantly higher than the other families, suggesting that Isotomidae and Onychiuridae/Tullbergiidae should have the widest range of habitat in soil depth distribution. Based on Simpson's D, alpha diversities of Isotomidae and that of Onychiuridae/Tullbergiidae were high, whereas those of Hypogastruridae and of Oncopoduridae were low. Beta diversities of Hypogastruridae and Tomoceridae were high, whereas those of Isotomidae and of Oncopoduridae/Tullbergiidae were low. The significant positive correlation between the SDW and alpha diversity and between SDW and contribution of alpha diversity to gamma diversity of family groups were found, indicating that the range of soil depth distribution among species within a family related with local diversity of collembolan family. The %OL and beta diversity were not significantly correlated. Negative correlation between alpha and beta diversities of family groups was found, indicating that families with high local diversity within a forest stand had low turnover diversity among forest stands in this site.
