Related Experiment Video
Updated: Jun 25, 2026
12:50
Continuous Instream Monitoring of Nutrients and Sediment in Agricultural Watersheds
Published on: September 26, 2017
Gatekeeper wetlands govern nutrient pathways in a continental basin
Michael A Dallosch1, Irena F Creed1
1Department of Physical & Environmental Sciences, University of Toronto, Toronto, ON Canada.
Communications Earth & Environment
|June 24, 2026
Summary
Headwater wetlands act as nutrient gatekeepers, storing nutrients when disconnected and exporting them when connected. Protecting these intermittently connected wetlands is key to reducing watershed eutrophication risk.
Area of Science:
- Environmental Science
- Hydrology
- Ecology
Background:
- Headwater non-floodplain wetlands are crucial for water quality but often excluded from nutrient management.
- Their role as nutrient gatekeepers in regulating downstream loads is not well understood.
Purpose of the Study:
- To investigate the function of headwater non-floodplain wetlands as nutrient gatekeepers in the Lake Winnipeg Watershed.
- To determine the relationship between wetland connectivity and nutrient export.
Main Methods:
- Utilized multi-decadal satellite imagery (1984-2020) to map wetland inundation and connectivity.
- Integrated annual nutrient load data (total nitrogen and phosphorus, 1994-2020).
- Employed random forest models to analyze nutrient export predictors.
Main Results:
- Nutrient export decreased when wetlands were hydrologically disconnected, indicating nutrient storage.
- Episodic reconnection led to increased nutrient export, showing a threshold effect.
- The proportion of disconnected wetlands was the strongest negative predictor of nutrient delivery.
Conclusions:
- Intermittently connected headwater non-floodplain wetlands act as significant regulators of nutrient transport at the basin scale.
- Conservation of these wetlands offers a scalable strategy to mitigate eutrophication in climate-vulnerable watersheds.
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