Single season growth response of Carex lyngbyei to additions of Branta canadensis guano analog

Estuarine ecosystems, crucial for supporting diverse biological communities, are facing habitat loss exacerbated by the regional invasion of non-migratory Canada geese. This study, set within the Little Qualicum River estuary—a national wildlife area vital for salmonid species—investigates the impact of Canada goose guano on the native sedge, Carex lyngbyei, a key estuarine plant species. I hypothesized that increased levels of goose guano would result in a reduction of Carex lyngbyei growth due to changing soil conditions caused by excess uric acid. To test this hypothesis, I employed a semi-controlled experimental design using exclosures to prevent goose access and applied a synthesized goose guano analog to transplanted Carex lyngbyei plugs. I monitored the growth response by measuring the leaf area of Carex lyngbyei at baseline and subsequent intervals. Leaf area was chosen as a measure of growth success as it a good indicator of primary productivity and can be obtained with non-destructive sampling techniques. The results indicated a high variability in leaf growth, with a trend towards constrained growth at higher guano concentrations. However, the substantial environmental noise within the estuary likely contributed to the observed variability, underscoring the complexity of estuarine ecosystems. Environmental noise refers to the variability in environmental conditions and other external factors that can obscure or interfere with the detection and interpretation of the response of the ecosystem to the added nutrients.