Population fluctuation and biodiversity of soil arthropods (myriapods) in Zagros forests (Case study: Ilam city)

The present study was carried out during a one year period in 2016-2017 in order to investigation of population fluctuation and biodiversity of soil mesofauna including myripods (Arthropoda: Myriapoda) of forests in Ilam region (Ilam Province, west of Iran). For this purpose, soil samplings were performed from three regions located at different altitudes of Gachan, Manesht and Ghalarang Mountains during different seasons of the year. Soil samples were transferred to the laboratory and myripods were extracted using the Berlese funnel. Totally, 730 specimens of centipedes and millipedes were collected and counted, all belonging to three families Dignathodontidae (Henia sp.), Scolopendridae (Scolopendra cingulata) and Julidae (Cylindroiulus sp. and Amblyiulus sp.). The maximum density of soil myripods in all three areas was observed in the spring; and their population density was higher in Gachan Mountain (147 centipedes / m2, 136 millipedes / m2) than in Manesht (111 centipedes / m2, 128 millipedes / m2) and Ghalarang (92 centipedes / m2, 131 millipedes / m2). In late autumn, population density decreased significantly in all three areas. Based on the results of analysis of variance, the effect of different seasons on population density of myripods in all three regions was significant at 1% level. Given the diverse vegetation in this area, the Shannon-Weiner and Simpson indices were high and optimal in all three areas. The results of Shannon's evenness index also showed that the value of this indicator for millipedes was higher than centipedes in all the three sampled areas. According to this study, myripods are potentially one of the main factors in food chain in Zagros forests and our results show the importance of biodiversity conservation and management of natural resources of this area.