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      A multi agency project funded by US EPA's STAR Program
Human Activity and Associated Stressors

Many human activities can cause "stress" to coastal margin ecosystems ().
We grouped the types of stresses caused by human activities into 5 major categories;
click on a category to see the human activities that are associated with each type of stress.

Major Stressor Category Types of Stress
Habitat Alteration:

Fragmentation of habitat
Dredging and filling
Conversion of land use

Chemical Disturbance:

Toxic contaminants
Nutrient additions
Salinity increases
Sediment additions
Atmospheric deposition of chemicals

Alteration of Biotic Processes:

Exotic species introductions
Changes in predation or grazing amounts
Overharvest of animals or plants

Alteration of Physical Processes:

Sediment additions
Temperature alterations

Hydrologic Disturbance:

Water level alteration
Stream flow alteration
Water table lowering

We will need to characterize many of these types of stress for the entire U.S. Great Lakes watershed. To do this, we will be making extensive use of geographic information systems (GIS) technology. GIS allows the building of map layers for anything that can be linked to a geographic coordinate system (i.e. has a latitude and longitude). For example, starting with a base map of the Great Lakes watershed we can add layers showing population density, location of agricultural fields, land usage type of all the land area, location of dredging operations, and so on. This work will be done at the NRGIS laboratory at NRRI.