The biodiversity and dynamics of oribatid mites in rice paddies

Abstract

Species abundance, biodiversity, distribution and population dynamics within and among oribatid mite communities were studied in rice paddies of China from October 1995 to November 1996. The Shannon-Wiener Index of Diversity and the Evenness Index indicated that the abundance and diversity of oribatids in rice paddies varied among locations and was lower than that of a typical forest ecosystem. The ability to resist environmental disturbance was low in the oribatid communities in sub-tropical monsoon areas and was more stable in monsoon temperate zones. The relative proportion of higher oribatid mites to lower oribatid mites in rice paddies is higher than that of other communities. The oribatid mites in paddy fields were mainly distributed in the upper layers of soil, which is similar to the distribution in the forest ecosystem, but the ability to distribute horizontally indicated their tendency to migrate freely within these layers. Water was an important factor allowing oribatid mites to migrate freely. The spatial distribution on rice plants indicated that mites were aggregated except there was a more even distribution in the later stages of rice maturity. Humidity and temperature, which are known to significantly affect oribatid communities in other habitats, did not significantly influence community structure on rice plants. The oribatid communities on rice was strongly affected by both mite migration and dispersion.