The Effect of Broad-leaved Tree Species on Abundance and Diversity of Earthworms in the Flat Forest Ecosystem

Earthworms are the most important soil detritivores in temperate forests. In the flat forests, earthworms have very important role on soil physical and chemical properties. This research was considered for studying the effect of broad-leaved tree species on abundance and diversity of earthworms in a flat forest located in Noor city, Mazandaran province, northern Iran. Soil samplings (50×50cm area) were carried out under closed canopy of broad-leaved tree species (oak, hornbeam, elm, Persian poplar, alder and walnut tree) at the 0-20cm soil depth. The results showed that the earthworms were belonged to Lumbricidae family, six genus (Dendrobaena, Bimasto, Lumbericus, Eisenia, Aporrectodea and Octotasion) and three ecological groups (Epigeic, Anecic and Endogeic). Dendrodrilus rubidus and Dendrobaena octaedra were the most frequent earthworm and fitted to Epigeic ecological group. Maximum population of Dendrodrilus rubidus was found understory of alder, oak and hornbeam. While the most abundance of Dendrobaena octaedra was found under walnut tree and elm. Tree species had no statistically effect on the mean abundance of earthworm ecological groups and biodiversity indices. Soil texture and pH were affected by tree species while soil water content didn’t show significant changes. Our finding indicated that earthworm can be used as bio-indicator of forest ecosystems assessment.