Reaction of topsoil earthworms groups to variability of ecological characters in a broad-leaved forest

AbstractEarthworms are as the most important soil forest ecosystem engineers. Present research was considered to study the reaction of earthworm group's (epigeic, anecic and endogeic) in topsoil to variability of ecological characters (litter C, litter N, litter C/N, soil C, soil N, soil C/N, and pH and moisture) in Noor Forest Park. Litter and soil samples were taken, with microplots of 30×30×15 cm, under tree canopy of Alnus glotinusa, Ulmus glabra, Popolus caspica and Parrotia persica species. Earthworms were collected during soil sampling, washed in water and weighed. Biomass was defined as the weight of the worms after drying at the labratory. Results showed that the soil under Alnus glotinusa has high abundance and biomass of epigeic (0.3 n/m2 amd 3 g/m2 respectively) and endogeic (1.4 n/m2 and 14 mg/m2 respectively). Whereas any epigeic and endogeic were not found under Parrotia persica. The least density and biomass (0.5 n/m2 and 0.5 mg/m2 respectively) of anecic earhworms were recorded under Parrotia persica. The results of this research are indicating of positive role of Alnus glotinusa species, related to high litter N, on biological index of soil quality that can be considered to restore of degraded parts in the northern Iran.