The Impact of Aquatic Habitat Destruction on Fish Populations and Biodiversity

Abstract

The current crisis of global biodiversity loss is none more apparent in the freshwater systems of this planet, wherein the aquatic habitat is steadily degrading under Anthropogenic pressures. The current paper provides a mechanistic understanding of habitat degradation in the Cauvery River Basin, which lies on the plateau of the Western Ghats, a major biodiversity hotspot. The conservation measures in this part of the Western Ghats are largely reactive, focusing on general water quality indicators and ignoring the site-specific and species-specific interactions between riparian degradation and population recruitment. Through 24 months of study, integrating high-resolution geospatial data, physicochemical parameters monitoring, and biological survey, it evaluated the extent of impact of a triad of stressors: fragmentation, sedimentation, and urbanization in aquatic habitats of the Cauvery River Basin. It developed an integrated computational framework (Python 3.10+) to analyze the relationship between habitat stressors and fish population by utilizing generalized additive models (GAMs) and habitat suitability index (HSI) modeling. The results indicate that 42% of the river length under study is suffering a high sedimentation rate that has led to 65% decrease in the abundance of endemic cyprinids in high stress zones. A strong negative relationship was observed between habitat fragmentation and species richness (R2 = 0.78, p < 0.001). Results suggest that management strategies focusing on flow regulation via dam construction are insufficient and an integrated connectivity-first conservation strategy based on riparian buffer rehabilitation and barrier mitigation is required.