Vol.: (0123456789) 1 3 Environ Monit Assess (2023) 195:902 https://doi.org/10.1007/s10661-023-11488-z RESEARCH Altitudinal and seasonal distribution of benthic macroinvertebrates in River Tons — a tributary of Yamuna River, Uttarakhand, India Basanta Kumar Das · Arghya Kunui · Saurav Kumar Nandy · Amiya Kumar Sahoo · Dharmendra Kumar Meena · Samir Kumar Paul · Uttam Kumar Sarkar · Kausik Mondal Received: 20 August 2022 / Accepted: 8 June 2023 © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2023 Abstract The main tributary of the Yamuna, the Tons River, exhibits altitudinal changes in its mac- roinvertebrate community’s diversity, abundance, and composition. Between May 2019 and April 2021, the study was conducted in the upper section of the river. A total of 48 numbers of taxa from 34 families and ten orders were recorded during the investigation. At this elevation of 1150 to 1287 m, the two most predomi- nant orders are Ephemeroptera (32.9%) and Trichop- tera (29.5%). During the premonsoon season, they had the lowest macroinvertebrate density (250–290 individuals/m2), and the post-monsoon season had the highest density (600–640 individuals/m2). During the post-monsoon season, the maximum larval forms (60%) of various insect orders were predominant. The findings indicated that lower altitudes (1150–1232 m) have higher macroinvertebrate abundance than higher ones. The diversity of dominance is shallow at site-I (0.0738) and strong at the site-IV during the premon- soon season (0.03837). Taxa richness, as measured by the Margalef index (D), peaked in the spring season (January to March) at 6.9 and reached its lowest point (5.74) in the premonsoon season (April to May). Only 16 taxa were discovered in site-I and site-II, but 39 taxa were discovered at low altitudes (site-IV, 1100 m) (1277–1287 m). The Tons River contains a total of 12 and 13 genera, respectively, that belong to the orders Ephemeroptera and Trichoptera, according to qualitative study of the macroinvertebrates. The current study supports the use of macroinvertebrates as bioindicator species for monitoring biodiversity and assessing the health of ecosystems. Keywords Ephemeroptera · Trichoptera · Diversity index · Tons River · Indicator · Elevation Introduction The benthic macroinvertebrate (BM) communities are integral part of fisheries, as they serve as food for many fish species and act as an essential part of the food chain and as bioindicators in rivers and streams (Fierro et al., 2017; Young et al., 2014). Physical, chemical, and biological characteristics can be used to monitor freshwater ecosystems (Navas-Pereira & Henrique, 1996). The variety of aquatic life is most prominent at the bottom, where aquatic species have evolved to a wide range of niches and exhibit a wide range of appearance and behaviour (Litsios et al., 2012). The creatures occupying the sediment or bot- tom substrates in freshwater, estuarine, and marine environments are benthic macroinvertebrates (Rice et al., 2012). Benthic creatures closely interacting with the substrate and the sediment’s components, texture, and chemical properties have a regulatory B. K. Das (*) · A. Kunui · S. K. Nandy · A. K. Sahoo · D. K. Meena · S. K. Paul · U. K. Sarkar · K. Mondal  ICAR-Central Inland Fisheries Research Institute, Barrackpore, Kolkata, West Bengal 700120, India e-mail: basantakumard@gmail.com