Temporal changes in human pressures and wetland response in the St. Lawrence River

Temporal changes (1970–2016) in St. Lawrence River wetlands were assessed between Cornwall and Québec to assess wetland response to cumulative anthropogenic pressures in the watershed. Emergent wetlands area and biomass of submerged aquatic vegetation (SAV) were contrasted among five regions subjected to sharply different water level/discharge regime (stabilized, semi-natural, tidal), nutrient concentrations and shoreline use (rural to urbanized). Between 1970 and 2016, over the growing season, St. Lawrence River mean water level have dropped and mean water temperature increased. Reductions in phosphorus concentrations were observed over time both in water and in SAV tissues, in phase with improvements of urban wastewater treatment and phosphorus reduction in upstream Lake Ontario. Nitrate concentrations in water increased and SAV biomass decreased between the 1970s and 2008 in the downstream regions of Lake Saint-Pierre and fluvial corridor subjected to the cumulative impacts from urban centers and intensively farmed watersheds. Over the 1970–2010 period, dropping water levels yielded slightly increasing wetland areas, owing to the downslope colonization of emergent and submerged plants. In urbanized regions, emergent wetlands shifted towards drier assemblages dominated by invasive reed species. Encroachment of wetlands by agriculture accounted for most wetland losses in rural Lake Saint-Pierre, which holds the single largest area of continuous wetland habitat of the entire watershed. The results highlight the strong response of riverine wetlands to a wide range of human pressures, including dropping water levels, changing nutrient concentrations, rising population and intensifying agriculture.

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Metadata Record Information

File Identifier
9190c9af-dd39-4192-a2e3-cd81a3c7ec88 XML
Date Stamp
2024-06-10T12:39:43.86Z
Metadata language

eng; CAN
Character set
UTF8
Hierarchy Level
Series
Point of contact
  Government of Canada; Environment and Climate Change Canada; Science and Technology Branch / Water Science and Technology / Aquatic Contaminants Research Division - ACRD Data Management Team
867 Lakeshore Rd. , Burlington , Ontario , L7S 1A1 , Canada
 

Data identification

Date (Publication)
2019-03-26
Date (Creation)
1970-04-01
Status
Completed
Metadata language

eng; CAN
Character set
UTF8
Topic category
  • Biota
  • Environment
Maintenance and Update Frequency
As needed
Spatial representation type
Text, table
Principal investigator
  Government of Canada; Environment and Climate Change Canada; Science and Technology Branch / Water Science and Technology / Aquatic Contaminants Research Division - Dr. Christiane Hudon ( Research scientist, retired )
Collaborator
  Government of Canada; Environment and Climate Change Canada; Science and Technology Branch / Water Science and Technology / Aquatic Contaminants Research Division - Maude Lachapelle ( Research biologist )
105 McGill St. , Montreal , Quebec , H2Y 2E7 , Canada
Collaborator
  Government of Canada; Environment and Climate Change Canada; Science and Technology Branch / Water Science and Technology / Aquatic Contaminants Research Division - Conrad Beauvais ( Physical scientist )
105 McGill St. , Montreal , Quebec , H2Y 2E7 , Canada
Collaborator
  Government of Canada; Environment and Climate Change Canada; Science and Technology Branch / Water Science and Technology / Aquatic Contaminants Research Division - Pierre Gagnon ( Mathematician )

Keywords

Place

  • St. Lawrence River

  • Lake Saint-Pierre

  • Lake Saint-Louis
Theme

  • All applicable data content

  • submerged aquatic vegetation (SAV), macrophytes, wetlands

  • nitrogen depletion, phosphorus, water level

  • St. Lawrence Action Plan (SLAP)

Government of Canada Core Subject Thesaurus

  • Environment

ECCC Information Category EN

  • Water - Quality

Business Functions

  • Monitor / Assess Substance and Waste Levels in Air, Water, Soil, Biota

  • Assess Toxicity, Manage and Monitor for Environmental Presence of Hazardous Substances and Waste

Branch

  • Science and Technology Branch

Directorate

  • Water Science and Technology

Environment Canada - Program

  • 1.2.1. Water Quality and Aquatic Ecosystems Health

GC Security Level

  • Unclassified

Geography

  • Quebec (QC)
 
Use Limitation

Open Government Licence - Canada ( http://open.canada.ca/en/open-government-licence-canada )

Access Constraints
License
Use Constraints
License
Begin Date
1970-04-01
End Date
2016-11-30

Extent

N
S
E
W
thumbnail


 
 

Ref. system Reference Systems

Reference system identifier
https://epsg.io / EPSG:4326 /
 

Distribution

Distribution Formats

Distribution format
  • CSV ( 1 )

 
Distributor
  Government of Canada; Environment and Climate Change Canada - Public inquiries centre
Fontaine Building 12th floor, 200 Sacré-Coeur Blvd. , Burlington , Ontario , L7S 1A1 , Canada
1-800-668-6767
https://www.canada.ca
 
 

Overviews

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S
E
W
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Keywords

All applicable data content Lake Saint-Louis Lake Saint-Pierre St. Lawrence Action Plan (SLAP) St. Lawrence River nitrogen depletion, phosphorus, water level submerged aquatic vegetation (SAV), macrophytes, wetlands
Branch
Science and Technology Branch
Business Functions
Assess Toxicity, Manage and Monitor for Environmental Presence of Hazardous Substances and Waste Monitor / Assess Substance and Waste Levels in Air, Water, Soil, Biota
Directorate
Water Science and Technology
ECCC Information Category EN
Water - Quality
Environment Canada - Program
1.2.1. Water Quality and Aquatic Ecosystems Health
GC Security Level
Unclassified
Government of Canada Core Subject Thesaurus
Environment

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