Caitlyn Rix (Honours thesis, 2022)
Caitlyn Rix
Project description: Gravel roads alter the surrounding environment in a myriad of ways that can influence surface-water flow, sedimentation runoff, and the delivery of dust and debris to nearby lakes. These changes have the potential to influence water quality and zooplankton communities in roadside lakes. Inspired by the results of recent studies, I hypothesized that: 1) higher calcium levels due to road dust deposition would lead to increased abundance of species of zooplankton that require high calcium levels; and 2) higher conductivity levels near the road would cause increases in species abundance but decreases in the species diversity and evenness of communities. I used zooplankton data from nine different lakes in the Boreal region in the Northwest Territories that fell into three distance categories from the Dempster Highway (0-300 m, 300-600 m, and >600 m). I analysed the resulting dataset using ANOVAs and a PERMANOVA to examine differences in richness, abundance, and species composition among lake distance categories. The ANOVA results for water quality variables and zooplankton community metrics showed no differences in means among the three distance categories. In addition, the principal component analysis did not show patterns suggesting that the relative abundance of zooplankton differed consistently based on distance from the road, and the PERMANOVA failed to find significant differences in zooplankton communities among road distance categories. Based on my results, it appears that road dust may not be having a measurable impact on roadside lakes. It is possible that natural variability among lakes masked any effects of road dust, and therefore future studies should consider incorporating information on important lake properties such as surface area and depth when examining the effects of roads on lakes.