The Effect of Spawning Salmon Presence on Riverbank Soil Organic Matter Content

Abstract

The decomposition of salmon along riverbanks releases an abundance of nutrients, such as nitrogen and phosphorus, into the surrounding soil. This leads to higher amounts of organic matter absorbed into the soil which greatly benefits river ecosystems (Bilby et al., 2003). We examined how the presence of spawning salmon affects the organic matter in soil found along
the riverbanks of three salmon spawning streams (Clayburn Creek, Capilano River, and Serpentine River) in comparison to the soil organic matter content of three creeks that do not support salmon (Poignant Creek, Coho Loop creek, and an unnamed creek in Meyer Glade, UBC Botanical Gardens). We measured the mass of organic matter in the soil (%) obtained from appropriate sampling locations, and predicted that the soil organic matter would be significantly greater when spawning salmon are present compared to the soil organic matter present in creeks that do not support salmon. Our statistical analysis showed that although on average the rivers containing salmon had a higher percentage of organic material in the soil, the results were not statistically significant and did not support our hypothesis that rivers that support spawning salmon will have more organic matter (%) in the soil along the riverbank compared to rivers that do not support spawning salmon.