Water Quality Parameters and Their Influence on Aquatic Faunal Diversity

Abstract

Urban freshwater lakes are increasingly exposed to anthropogenic pressures that degrade water quality and threaten aquatic biodiversity. This study examined the influence of spatial and seasonal variation in water-quality parameters on aquatic faunal diversity in Kapra Lake, an urban freshwater lake in Hyderabad, India, using an analytically structured dataset representing a three-site inflow–disturbance gradient and three seasonal periods. Water quality was evaluated using key physicochemical indicators, including dissolved oxygen, organic pollution indices, and nutrients. Aquatic faunal diversity was assessed using macroinvertebrate community metrics. Results revealed pronounced spatial differences in water quality, with lower dissolved oxygen and higher organic and nutrient loading at high-exposure sites compared with low-exposure sites. Correspondingly, macroinvertebrate diversity was lower at impacted zones and higher at less disturbed locations, while seasonal effects were comparatively weaker. Correlation and regression analyses demonstrated positive relationships between dissolved oxygen and faunal diversity and strong negative relationships with organic and nutrient enrichment indicators. Multivariate ordination identified a dominant enrichment–oxygen gradient explaining most water-quality variability and structuring faunal patterns across sites. The findings highlight the critical role of localized water-quality degradation in shaping aquatic faunal diversity and underscore the importance of integrated physicochemical and biological assessments for effective monitoring and management of urban freshwater lakes.