Aquatic insect diversity of a protected area, Keibul Lamjao National Park in Manipur, North East India

•Presence of tolerant orders like Odonata, Hemiptera and Coleoptera•Absence of sensitive orders of aquatic insects in all the sites of the floating park•Shannon H' values are less than 1 in all the sites.•Very low DO concentration in water of the park•Lead and mercury concentrations were found beyond the desirable level of WHO and BIS.

Keibul Lamjao National Park, only home of Brow-Antler Deer, (Rucervus eldii eldii) is the unique floating park of the world. It is a part of the Loktak Lake, Manipur (Ramsar site). The lake gets major share of water from seven feeder rivers. In this paper an attempt has been made to study aquatic insect diversity of the five sites of the national park area which will indicate the health of the unique but deteriorating ecosystem and at the same time reduce aquatic insect data deficiency of the area. The study recorded 3 orders, 12 families and 23 species of aquatic insects. Besides inventorying the aquatic insect taxa, their relationships with several environmental variables including heavy metals were also investigated. The low Shannon Weiner Diversity Index values of aquatic insects (Shannon H' less than 1 in all the sites) indicated perturbed condition of the water of the National Park area. The study revealed very low dissolved oxygen (DO) in all the sites. All the three heavy metals in most of the sites were found beyond the desirable level of BIS (IS 10500: 1991). Different biological monitoring scores and Canonical correspondence analysis (CCA) have been used for discussion and interpretation. This study found that although protected areas are meant for protecting biodiversity, management of outside protected area particularly catchment area should be given priority for minimizing land use disturbance, altered hydrology and other related factors.

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