The ecological and systematic investigation of the oribatid mites of Kocaeli city forest

The oribatids, the richest member of the microarthropods, play an important role in the decomposition processes occuring in the soil. They decompose residues such as plants, animals, fungi, algae and fecal matter and provide the formation of humus, thus help to increase soil fertility and biodiversity. They respond to changing climate and soil factors. Temperature and humidity, which are among the important factors in the distribution of oribatids, may cause a decrease in the density of oribatids in climate change. In this study, soil samples from five different stations were taken between December 2016 and November 2018 in order to determine the species richness and abundance of oribatids inhabiting Kocaeli City Forest. Species identification was carried out using both light and electron microscopes. Identification of oribatids revealed that they were represented with 75 species in the forest. This is a significant finding since the number of oribatid mites reported from Turkey is 239. Moreover, out of 75 species determined in this study 12 species belonging to 7 genera are new records for Turkey. So the total number of oribatids reported from Turkey has increased to 251 and %30 of the all oribatids of Turkey is present in Kocaeli City Forest alone. Systematically these 75 species are representatives of 69 genera belonging to 47 families under the order: Oribatida. The highest number of individuals were obtained in KKO2 station in September, 2017. Data relating to parameters such as soil moisture, soil organic matter content, soil surface temperature, pH, electrical conductivity and salinity were taken second year each month during the sampling. These parameters were used to assess the effects of the abiotic factors on the presence and the abundance of oribatids in the microhabitat in Kocaeli City Forest. The effects of the parameters was determined with the application of Principal Component Analysis (PCA). It was observed that, interestingly, water and temperature related parameters has revealed counter-effects on the abundance of the oribatids. PCA has shown that temperature related parameters affected the presence of the oribatids positively whereas the the effect of water related parameters were negative. Correlation tests were also supported the results of PCA.