A reliable method for quick comparisons of enchytraeid (Oligochaeta) densities in soil and their seasonal changes under cultivated and natural fields in central Greece

Although Enchytraeidae constitute an important component of soil fauna, their communities have not been adequately studied in cultivated soils. We studied the species composition and the seasonal fluctuations of the enchytraeid communities in a four-year alfalfa plantation and its boundary zone in the valley of Kopaida, Central Greece for a period of one year. The population densities were recovered at 15 cm depth. There were remarkable seasonal changes in the population densities that took their highest value in autumn and their lowest in summer in both soils. The composition of the plantation community consisted of two distinct species with opportunistic life strategy and developed higher density compared to the boundary zone. The boundary zone harbored four species which mainly had robust, long living developmental pattern. We concluded that the specific characteristics of the dominant plant species were the most decisive differentiating factor determining the enchytraeid communities, followed by the cultural practices. The results from the sucrose centrifugation method of extraction exhibited strong correlation with those of the cold wet extraction method without filtering. This indicates that sucrose centrifugation method can be safely used in quickly processing high number of samples and for the enchytraeid estimation in multidisciplinary research works.