Spatial and temporal assessment of rural-urban land-use gradient effects on water quality and periphyton communities in tributaries of Durham Region, Ontario

Abstract

This study examines the effects of longitudinal and local land-use gradients on water quality and periphyton within four watersheds representing varying rural-urban land-use types and intensities. Although numerous studies have identified how specific land-use gradients (e.g., urban or agricultural land-use) affect water quality and periphyton, it is not fully understood how varying intensities and types of rural-urban land-use gradients affect water quality and algae both within and across watersheds sharing similar physiography and climate. Therefore, this study aimed to determine how variation in rural-urban land-use gradients affect water quality and periphyton along the cumulative flow path of tributaries (i.e., longitudinal), as well as across tributaries where sites were approximately matched for distance from headwaters. To assess spatial variation without the confounding effects of seasonality, I analysed water quality, algal biomass, and community composition from a set of algal growth substrates that were deployed in all study creeks (Lynde, Oshawa, Bowmanville and Soper) during May, 2015. Additionally, I examined the spatial and temporal variation of water quality and algal community structure in all tributaries from May – August, 2015.