Unveiling Fish Community Response to Anthropogenic Stressors in Tributary Streams of Pamba River in the Western Ghats

Abstract

The anthropic impact on stream environments is increasing uncontrollably and affecting rich biodiversity. The intensity of anthropogenic stressors and their influence on the fish community was studied from the tributary streams of the Pamba river in the Western Ghats from January to December 2019. We quantified the anthropogenic stressors using a metric scale, which combines the severity and proximity of the stressor to the stream environment. Agricultural practices, riparian cover removal, hydrologic modifications, tourism, and pilgrimage were recorded as major stressors in the investigated streams. In this study, human pressure significantly affected the ichthyofaunal community in the streams. Generalists were found to be more tolerant of environmental stress in their respective sites, whereas specialists were adversely affected. The stream with a high intensity of stressors supported greater ichthyofaunal diversity, especially those of generalist fishes. Streams with an intermediate level of disturbances were noted to support high species richness. In the Western Ghats streams in Kerala, the ichthyofaunal response to human pressure is not well documented. This study is the first of its kind to concentrate on how ichthyofauna reacts to stressors caused by humans. The variety of stream fish assemblages in the Western Ghats must be preserved, which calls for regular monitoring of stressors.