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Mapping Great Lakes Threats

Mapping Great Lakes Threats

The research team used the combined influence of 34 different threats to map environmental stress on the Great Lakes. (Image courtesy of University of Michigan)

Host: Rebecca Williams
Show date: 12/18/2012

Summary:

This is the Environment Report. Iím Rebecca Williams.

The Great Lakes are under a lot of stress. 

34 different kinds of stress, to be exact.

Thatís according to a research team that has produced a comprehensive map showing many of the things that stress the Great Lakes.  Think: pollution, invasive species, development and climate change... just to name a few. 

To learn more about this new map, I went to visit David Allan. Heís a professor in the School of Natural Resources and Environment at the University of Michigan, and heís one of the people who led the project.

I asked him why he wanted to take on something like this:

David Allan: ďSo we set out to answer the question, what are the most important stressors in the Great Lakes, whatís the cumulative influence of environmental stressors in the Great Lakes, and whatís their spatial distribution Ė how do they vary from place to place? And we did that with the help of many by developing individual maps with 34 different environmental stressors; they represent invasive species and climate change and coastal development and contaminated sediments and land runoff, and we developed these individual stressor maps and then we combined them in a variety of ways but basically summed their influence so that we have the first ever spatial pattern of cumulative impact of humans on the Great Lakes."

RW: ďLetís take a look at the map - we have it pulled up here Ė and itís a colorful map and I can see thereís a key, the stress index, and it goes blue to red. Letís take Lake Erie for example, we see an awful lot of red indicating relatively higher stress along these areas of Lake Erie. Whatís going on there?Ē

David Allan: ďSo, Lake Erie certainly shows up as one of the lakes that has the highest value for our stress index. I donít think thatís a big surprise to anyone. What is surprising though is the number of stressors that influence these coastal waters in particular. I think these coastal waters are most strongly stressed because theyíre experiencing stressors that are occurring in the lakes themselves like invasive species and contaminated sediments, and they experience all the runoff from the land and all the aquatic habitat disruption that goes with coastal development.  And so, weíd have to look at the numbers to tease it out but there might be 18 or 20 or more of our stressors all having an influence on some of those coastal waters of Lake Erie, and thatís what gives it the red appearance on our map.  Itís the significantly larger number of stressors that are co-occuring in those locations.Ē

RW: ďSo whatís being done to reduce the stress on the lakes?Ē

David Allan: ďSo, right now, we are in the middle of a really important and useful set of activities called the Great Lakes Restoration Initiative and itís invested over a billion dollars of federal money in Great Lakes restoration.  So, restoration is a mix of activities. We did another set of mapping.  We mapped all the locations that we could identify where restoration is taking place.  And we asked the question, would we have picked those places as well, and the answer was yes.  So, those restoration dollars are being invested in locations that we agree are places that are red on our map, they are places of high stress.  They tend to be places also that provide a lot of benefit to humans.  So, itís a good thing that itís taking place.Ē

David Allan is a professor at the School of Natural Resources and Environment at U of M.  Iím Rebecca Williams.

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