Clair Bidez, Westminster College
Life Sciences
Changes to stream ecosystems due to urbanization are known to degrade riparian ecosystems through multiple stressors including increased erosion and sedimentation, expansion of impervious surface leading to altered flow regimes, degradation of riparian vegetation and habitat, and nutrient contamination. Ultimately, such degradation can inhibit ecosystem services such as contaminant filtration and nutrient cycling. This study examined the effects of urbanization on the function of riparian communities in three streams in the Salt Lake Valley watershed. We attempted to characterize these changes through monthly monitoring in urban and non-urban reaches of the same streams. Specifically, we measured periphyton biomass (as measured by chlorophyll-a) as a known indicator of nutrient pollution and a proxy of riparian health. In addition, we monitored water quality parameters including temperature, dissolved oxygen, and dissolved nitrate concentration. The urban reaches of the streams contained 3.6 to 9.3 times the dissolved nitrate concentration as their non-urban counterparts. Mean stream periphyton biomass was positively correlated with mean stream nitrate concentration for each reach. These findings point to urbanization as a potential source of ecosystem degradation in the Salt Lake Valley. They suggest that long-term monitoring is warranted, along with an in-depth investigation into the ultimate mechanisms responsible for the degradation.