6/6/13

IAGLR Day 4: Edging closer to tipping points

IISG's science writer, Anjanette Riley, is at the 2013 International Association for Great Lakes Research conference at Purdue University. She’ll be blogging from the sessions all week providing an inside look at the newest research on the health of the Great Lakes. Here’s today’s post: 

“I have spent the last day of the conference learning about tipping points—the thresholds that, if crossed, will change the state of an ecosystem. Think of water in winter. When temperatures first start to fall, the water will stay in its liquid form. But the nature and function of that water will change dramatically as soon as the temperature reaches freezing. 

The work discussed in a session that began yesterday afternoon and carried into today was focused on finding the land-use thresholds that would change how aquatic ecosystems function if crossed. Many of the presentations talked about causal relationships between things like water temperature and the development of different species of salmon, or a loss of oxygen and the health of the food web. Understanding these relationships moves us towards identifying specific land use practices that, for example, could change water temperature or oxygen levels so much that an ecosystem could no longer function like it should.

Some presenters, though, did report on specific tipping points they had uncovered. For example, communities can expect to see impaired ecosystems when the relative amount of medium-high density urban land in a river basin exceeds 10 percent. Much of Michigan, Wisconsin, and Illinois have either already passed this threshold or are close to it.

Several presenters were quick to remind me and my fellow attendees that ecosystems are complex and interconnected. Crossing a single tipping point will not necessarily have as dramatic a result as the water temperature reaching freezing. The more land-use thresholds a community crosses, the more impaired the nearby waterways will become.

During the session, we were also taken through a new web-based system that uses the tipping points identified by researchers to help land-use planners make sustainable decisions. The system helps planners identify natural resources like open spaces and surface water in their area, assess their conditions and where they stand relative to known tipping points, determine where they will be in the future if land use practices stay the same, and identify how to avoid crossing a tipping point or restore ecosystems that have already been altered. With these tools in hand, it will be easier for planners to identify at-risk areas and determine the most effective actions to take.”
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The research and the support tools Anjanette discussed are part of a 4-year project funded by EPA and NOAA. The project is a collaboration of outreach specialists and researchers from universities across the basin and various Great Lakes Sea Grant programs, including IISG.

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