Abstract

Stream channelization and modification is a widespread practice on agricultural land in Monteregie, Quebec, however, it is well known that channel simplification reduces the variability of instream habitat complexity and affects the biodiversity of these streams. Despite over 30,000 km of streams being subjected to channelization-type development in Quebec, very little is known about the extent of stream degradation and effects it may have on local geomorphology and ecology. The Morphological Quality Index (MQI) is a tool used to measure a stream’s hydrogeomorphological quality and has been shown to be a reliable predictor to help assess habitat quality in small headwater streams. The purpose of this research is to determine the health of fish communities in small streams in Monteregie and assess whether there is a significant relationship between biological communities and the MQI. Over 1,220 fish samples and 85 stream reaches with drainage areas less than 130 km2 were analysed in Monteregie. Results showed that small streams in Monteregie were higher in fish biodiversity than expected, with clear relationships between the fish metrics and proportion of land use in forested or agricultural categories. The MQI was also able to predict biological communities with up to an R2 = 0.50, which shows that the MQI could be used as a reliable tool to efficiently assess streams while providing insight on how stream modification affects overall biodiversity in agricultural watersheds.