Spatial insect diversity paradigms and related ecosystem services in the protected Nandhour Landscape of India

The Nandhour Landscape located in an eco-fragile biodiversity rich Terai Arc Landscape of India is protected in the form of a wildlife sanctuary and is least explored in terms of insect diversity and functions. Therefore, this study aimed to provide baseline information on the biodiversity of insects and their ecological functions in tropical to sub-tropical forest ecosystems which is important for the successful long-term provisioning of ecosystem functions and services in the protected landscape. Using standardized sampling techniques, the present study examined the structure and composition of insect assemblages in terms of their comparative diversity and richness across a range of habitat types in the Nandhour Landscape. Besides, the present study also evaluated the ecological significance of insect fauna. A total of 230 insect species belonging to 47 families and nine orders were recorded from various habitats and Lepidoptera was the most dominant insect order in terms of both richness and abundance, followed by Coleoptera, Hymenoptera, Odonata and others. Species diversity and richness were the highest in dense moist and open dry riverine forests, while the least in plantation forest and agricultural land. The heterogeneous structure and composition substantiated the importance of overall spatial heterogeneity and natural forests in sustaining and maintaining the rich insect diversity. Conservation of insect diversity is highly important as several species provide crucial ecosystem services and aid in the functioning of various ecologically fragile habitats of the landscape.