Impact of Riparian Buffer Strips on Aquatic Phosphorus Concentrations: Insights into Effective Land Management Strategies

Abstract This study examined the effects of riparian buffers on the concentrations of soluble reactive phosphorus (SRP) in water and available phosphorus in sediment samples collected along Washington Creek, a moderately degraded stream typical of agricultural landscapes (AG) in Southern Ontario. This research was performed along the entire length of the creek (9250 m). Four different land uses were identified in the study area: natural forest (NF), rehabilitated forest (RH), grassland (GR), and agricultural field (AG). Although the concentrations of SRP in water samples were much lower (i.e., < 0.001 ppm) than the federal-provincial water quality objectives for streams (i.e., 0.03 ppm), the concentrations of SRP in the water samples collected from plots adjacent to the AG without riparian buffers were significantly higher than those from areas covered with vegetated buffers. The concentrations of available P in the sediments collected from the plots influenced by AG were significantly higher than those with riparian buffers, which was up to 5.2 mg P kg− 1 sediment. This study showed the accumulation of available P in the sediments was correlated with SRP concentrations in Washington Creek. These findings suggest that the implementation of riparian buffer strips can effectively mitigate the influx of phosphorus into aquatic systems, thereby reducing the risk of eutrophication and maintaining water quality within acceptable limits.