Diversity, Richness, Dominance and Evenness Indices of Phytoplankton Community at Warm Water Fish Ponds at Dighche Zone, Golestan Province

The aim of this study was estimate the diversity, Richness, dominance and Evenness indices of phytoplankton community of fish ponds water in Dighche zone at east of Golestan Province. Sampling were done during one culture period from June to November 2011. The results show that there are no significant differences between different ecological indices in 3 ponds and different seasons (P>0.05). In the present study diversity, Richness, dominance and Evenness indices for phytoplankton ranged from 1.06-1.17, 0.79-0.83, 0.36-0.42 and 0.63-0.66. The highest value of diversity, Richness, dominance and Evenness indices belongs to pond 3, 2, 1 and 2 but lowest value observed at pond 1, 1, 2 and 1. Diversity index at fall and spring season had highest and lowest value. Richness index at summer and spring season had highest and lowest value. Dominance index value at spring and same in summer-fall seasons had highest and lowest value. Evenness index at spring and summer seasons had highest and lowest value. The correlation analysis between ponds water physico-chemical parameters and different ecological indices show that diversity and dominance index had high and significant correlation with P-PO4 parameter with -0.868 and 0.864 respectively. But these relatives don't observe between other parameters. The results show that different ecological indices of phytoplankton community at fish ponds affected by Soil, water physico-chemical parameters and management of a fish ponds ecosystem.