Integrated measures of anthropogenic stress in the U.S. Great lakes basin.
Integrated, quantitative expressions of anthropogenic stress over large geographic regions can be valuable tools in environmental research and management. Despite the fundamental appeal of a regional approach, development of regional stress measures remains one of the most important current challenges in environmental science. Using publicly available, pre-existing spatial datasets, we developed a geographic information system database of 86 variables related to five classes of anthropogenic stress in the U.S. Great Lakes basin: agriculture, atmospheric deposition, human population, land cover, and point source pollution. The original variables were quantified by a variety of data types over a broad range of spatial and classification resolutions. We summarized the original data for 762 watershed-based units that comprise the U.S. portion of the basin and then used principal components analysis to develop overall stress measures within each stress category. We developed a cumulative stress index by combining the first principal component from each of the five stress categories. Maps of the stress measures illustrate strong spatial patterns across the basin, with the greatest amount of stress occurring on the western shore of Lake Michigan, southwest Lake Erie, and southeastern Lake Ontario. We found strong relationships between the stress measures and characteristics of bird communities, fish communities, and water chemistry measurements from the coastal region. The stress measures are taken to represent the major threats to coastal ecosystems in the U.S. Great Lakes. Such regional-scale efforts are critical for understanding relationships between human disturbance and ecosystem response, and can be used to guide environmental decision-making at both regional and local scales.
Danz
Nicholas P
NP
Center for Water and the Environment, Natural Resources Research Institute, University of Minnesota Duluth, 5013 Miller Trunk Highway, Duluth, Minnesota 55811, USA. ndanz@nrri.umn.edu
Niemi
Gerald J
GJ
Regal
Ronald R
RR
Hollenhorst
Tom
T
Johnson
Lucinda B
LB
Hanowski
JoAnn M
JM
Axler
Richard P
RP
Ciborowski
Jan J H
JJ
Hrabik
Thomas
T
Brady
Valerie J
VJ
Kelly
John R
JR
Morrice
John A
JA
Brazner
John C
JC
Howe
Robert W
RW
Johnston
Carol A
CA
Host
George E
GE
D000383:Agriculture; D000818:Animals; D001717:Birds; D017753:Ecosystem; D004787:Environmental Pollution; D005399:Fishes; D040362:Geographic Information Systems; D006114:Great Lakes Region; D006801:Humans; D011156:Population Density; D025341:Principal Component Analysis