WATERSHED MICROBIOMES AND HABITAT SUITABILITY OF THE ORIENTAL DARTER IN A UNIVERSITY CAMPUS ECOSYSTEM

Abstract

Freshwater ecosystems in semi-urban landscapes are highly sensitive to changes in water quality, biological processes, and land-use patterns. The present study evaluates the habitat suitability of the Oriental Darter (Anhinga melanogaster), a Near Threatened aquatic bird, within the Assam Don Bosco University (ADBU) Tapesia Campus by integrating physicochemical water analysis, microbial community profiling, avian observations, and GIS-based spatial assessment. Physicochemical parameters including pH, dissolved oxygen (DO), free carbon dioxide (CO₂), alkalinity, and hardness were analyzed across selected aquatic sites. Systematic field surveys were conducted to record Oriental Darter sightings and behavioural patterns. Metagenomic analysis of water from preferred habitats was carried out using 16S rRNA gene sequencing, followed by bioinformatic processing to characterize microbial community composition. GIS tools were employed to map land use, bird sightings, and habitat suitability gradients across the campus. The results showed that the Oriental Darter preferentially occupied lake habitats exhibiting neutral pH, higher dissolved oxygen, and lower carbon dioxide levels. These sites supported balanced freshwater microbial communities involved in nutrient cycling, while sites with poorer water quality showed microbes associated with organic enrichment and ecological stress. GIS-based habitat suitability mapping corroborated field observations, identifying spatial clusters of high suitability aligned with favourable water quality and biological conditions. The study highlights the value of integrating water biochemical parameters, microbiome data, avian bioindicators, and geospatial analysis for assessing freshwater ecosystem health. The findings provide baseline ecological information for campus-level conservation planning and demonstrate a replicable framework for monitoring semi-urban aquatic ecosystems.