Understanding riparian health through multi-metric indicators: a case study from Southern India

Riparian ecosystems face degradation due to anthropogenic pressure, affecting biodiversity, food and water security, and the livelihoods. Adapting methods to assess riparian health locally and effectively is a pre-requisite for habitat monitoring and restoration interventions. In India, river health monitoring is largely limited to water quality and discharge measurements, with sparse biodiversity assessments. To fill the gap of a more comprehensive river health assessment, we adapted existing multi-metric indices. The indices are the fish-based Index of Biotic Integrity (IBI), the Bird Integrity Index (BII), a modified QBR (Qualitat del Bosc de Ribera), and the Riparian Strip Quality Index (RSQI). We considered plants, fishes and birds as representative taxa for terrestrial, aquatic and land-water transition zone, respectively. We used a nested hierarchical sampling approach to select nine one-km long segments (44 reaches) located along two streams of Moyar-Bhavani-Noyyil sub-watershed in southern India. The indices showed an overall decreasing trend moving downstream, and the lowest values were observed for agricultural (non-protected) sites. Only QBR and RSQI showed statistically significant difference across PA and NPA. BII could not be computed because of lack of statistically significant relationship between disturbance index and the bird metrics. RSQI offered limited insights but can complement IBI and QBR.