The relationship between biodiversity and ecosystem functioning is a central issue in ecology. The insurance hypothesis suggests that biodiversity could improve community productivity and reduce the temporal variability of main ecosystem processes. In the present study, we used a plankton community that was investigated from September 2012 to November 2013 in Sansolav pond of Bikaner District to test this hypothesis and explore the mechanisms involved. As a result, 17 zooplankton and 15 phytoplankton are showed apparent monthly variations. The average temporal stability index of zooplankton taxa lower significantly higher than that of phytoplankton. Complex relationships were observed between the species richness and temporal stability of different phytoplankton taxa: a unimodal relationship for both Cyanophyceae and Bacillariophyceae, Chlorophyceae and total phytoplankton. These relationships were primarily controlled by the portfolio effect; while the effects of over yielding and species asynchrony were relatively weak. Phytoplankton species richness had a significant positive influence on the temporal stability indices of protozoa, Rotifera and total zooplankton, while its influence on Cladocera and copepods was not significant. The dominant mechanisms were found to be ‘trophic over yielding’ these results demonstrated that the effects of diversity on community stability can be complex in natural ecosystems. In addition, the diversity of phytoplankton not only influenced its own temporal stability, but also affected the stability of zooplankton through trophic interactions
