Aquatic insect diversity in two temple ponds of Silchar, Assam, N.E. India and their conservation values

A study was carried out on the diversity and density of aquatic insect community in the two urban temple ponds – Radhamadhav akhra pond and Mandir dighi pond of Silchar town, Assam, Northeast India. All total 22 taxa of aquatic insects were recorded, 13 taxa from Radhamadhav akhra pond and 18 taxa from Mandir dighi pond. 9 taxa were found common in both the ponds. In Radhamadhav akhra pond classical relationship of dissolved oxygen and free carbon dioxide was established with low dissolved oxygen and high free carbon dioxide concentration. Pearson correlation coefficient analysis showed that the number of taxon was highly correlated with the density of taxon in both the ponds. Canonical correspondence analysis revealed that for Radhamadhav akhra pond, eigen values were 0.784 for axis 1 and 0.630 for axis 2 while for Mandir dighi pond eigen values were 0.825 for axis 1 and 0.740 for axis 2. Taxon-environment correlation showed that aquatic insect community and environmental variables were highly correlated in both the ponds. Shannon diversity index of Radhamadhav akhra pond was in the range of 1.5−1.7 and Mandir dighi pond was in the range of 1.9−2.0. According to the dominance status by Engelmann’s Scale, only Rhagoveliasp. was found Eudominant in Radhamadhav akhra pond. No eudominant taxon was found in Mandir dighi pond.