Footprint, urban growth and insect diversity in Garbhanga reserve forest adjoining Guwahati metropolitan city of Assam, India

This study was conducted at two sites, Lokhra and Basistha, within the Garbhanga Reserve Forest from March to August 2023, with a focus on enumerating insect diversity, which is a key to determining forest health. A total of 79 insect species, comprising 831 individuals, were recorded from both sites. 44 species with 517 individuals were recorded at the Lokhra site, and 35 species with 314 individuals from the Basistha site. Among all the orders, Lepidoptera have been found in the greatest number at both experimental sites. The Shannon index of diversity is higher at the Lokhra site (3.52) than at the Basistha site (3.33). Again, Simpson’s diversity index is 0.0623 at the Lokhra site and 0.045 at the Basistha site. The Margalef index for species richness was 6.58 at the Basistha site, and in the Lokhra site, it was 5.96. The Pielou index for species evenness was 13.16 and 11.8 at the Lokhra and Basistha sites, respectively. This study showed the rich insect biodiversity and excellent health of the reserve forest.