Oribatid mite species diversity in two agricultural ecosystems of Khorasan-e-Razavi Province Iran

This study was carried out to investigate oribatid mite species diversity of two agricultural ecosystems in Khorasan-e-Razavi Province. Samplings have been done monthly in a three-year old alfalfa field with an area of two hectares, and a fruit orchard with an area of 0.6 hectare from April to October 2014. In each month, 10 soil samples were randomly taken with equal volumes from depth of 0-20 cm, totally 60 samples. Berlese funnel was used to extract the oribatid mites and collected individuals were then cleared, mounted on microscope slides and identified based on external morphological characters and supposed as morphological species. Community structure, Alfa diversity indices and nonparametric estimation of maximum species richness in both ecosystems with five relevant methods were determined. From the total 1425 collected individuals, 1097 individuals including 40 species and 328 individuals including 25 species were belonged to the orchard and alfalfa ecosystems, respectively. The orchard ecosystem has a higher species richness as well as species diversity compared to that of the alfalfa one. The relative abundance of oribatid species in the orchard was also more equitable than that of alfalfa field. Estimation of the maximum species richness (Smax) in these two ecosystems with the five relevant methods showed that the number of detectable species in alfalfa and orchard ecosystems will increase to 54 and 185 species, respectively. The probable indications on the change in the oribatid mite species diversity in these two ecosystems are discussed.