GLEAM

Great Lakes Environmental Assessment and Mapping Project

Lake Stressors

Stressor Map

Explore the spatial distribution of cumulative stress and of individual stressors using this interactive map. You can use the layer switcher in the top right corner of the map to turn individual stressor layers on and off.

Cumulative stress to the Laurentian Great Lakes is determined from 34 individual stressors, along with habitat and lake-specific weights derived from an extensive survey of Great Lakes researchers. A stressor is defined in this project as a pressure, which exceeds its range of normal variation due to human activity, affecting species, biological communities, or ecosystems.

Great Lakes stressors were divided into seven categories:

  • Aquatic habitat alterations: Changes to aquatic habitat from diverse causes, such as shoreline hardening and erosion control structures, port and marina development, and tributary dams
  • Climate change: Changes to seasonal, average, and extreme temperature, precipitation, and ice cover
  • Coastal development: Land-based human development near lake margins, such as residential and commercial development and industrial activities
  • Fisheries management: Changes to Great Lakes ecosystems resulting from fishing pressure, stocking activities, and aquaculture
  • Invasive species: Changes to Great Lakes ecosystems from invasive and nuisance species in abundances not previously seen
  • Nonpoint source pollution: Nutrients, sediments, and waterborne contaminants transported from watersheds to the Great Lakes by streams and rivers and atmospheric deposition
  • Toxic chemical pollution: Chemical pollutants from industrial and agricultural sources