Impact of macro vegetation and edaphic variables on the distribution and diversity of Oribatida (Acari) in Northern Tripura, India

In this communication results of an ecological study of soil Oribatida from Northern Tripura, India have been incorporated. Soil samples were collected fortnightly from two sites over a period of one year (July 2016 to June 2017). An attempt has been made to determine the extent to which macro vegetation, edaphic variables and local microclimatic conditions influence the community structure of Oribatida. Among the 14 species under 12 genera identified, species of the genera Scheloribates, Protoribates and Galumna were the major contributors representing 34.27%, 16.93% and 7.58% of the total population, respectively. Species of Scheloribates and Protoribates were common and dominated in both sites. The oribatid abundance exhibited an irregular and significant trend of fluctuation with a maximum in winter and a minimum in the monsoon period. Out of four edaphic variables analyzed, only the organic matter content and pH showed a positive and significant correlation with oribatid abundance, while temperature and moisture revealed a significant negative correlation. It was interesting to note that although the study sites were close to each other and were more or less similar in topological, edaphological and climatological conditions, with a little variation in distance and vegetation cover they exhibited variations in both oribatid species abundance and diversity. The reason behind the seasonal variation and differences in abundance and species diversity in the studied sites was highlighted. Further extensive and comprehensive research on oribatids is needed in the region of Tripura.