A Watershed Moment: Development of a Multimetric Stream Index of Biotic Integrity to Assess the Ecological Integrity of the Credit River in Ontario, Canada

Abstract

The Stream Index of Biotic Integrity (S-IBI) was developed in order to measure the ecological integrity of Credit River watershed streams. One goal of this research is to offer a predictive tool using a select suite of metrics that include benthic macroinvertebrate, fish, and riparian vegetation data. This tool was developed using stream monitoring data collected during 2011 through 2014 as part of Credit Valley Conservation Authority’s (CVC) Integrated Watershed Monitoring Program. The six metrics included in the S-IBI using the Kruskal-Wallis H Test analysis of variance to examine data significance and the Spearman Rank Correlation to prevent redundancy in metric selection; they are predictive of ecological disturbance as expressed through land use data that encompasses the natural environment, agricultural landscapes, and developed land. S-IBI scores were compared over time and across the Credit River Watershed’s three physiographic zones and found differences in the effectiveness of management across the zones. The S-IBI is meant to provide practitioners with a rapid modular assessment to enable a targeted and easy-to-update tool that will help them to proficiently manage and respond to the ecological state of the river, as well as to clearly communicate these response with local stakeholders using letter grades associated with S-IBI scores. While this tool has predictive powers in relation to environmental stressors, it should be assessed for adjustments to metric inclusion and will be further refined in future years based on CVC’s expertise, best management practices, and protocols.