New, ultra-detailed maps of Great Lakes recreational use will inform restoration priorities

They mapped places used for sport fishing, recreational boating, birding, beach use and park visits for all five Great Lakes and included sites in both the United States and Canada. The recreational sites were then compared to the research team's previously published "threat maps," which show the location of 34 Great Lakes environmental stressors.

Taken together, the maps showing intensity of recreational use as well as environmental stress provide federal and regional officials with an unprecedented scientific foundation upon which to sustainably manage the Great Lakes, where current restoration efforts exceed $1.5 billion, the researchers conclude.

"Restoration priorities are typically based on the evidence for environmental degradation without explicitly accounting for the benefits people receive from ecosystems, which include recreational opportunities," said lead researcher David Allan, professor emeritus of aquatic sciences at the U-M School of Natural Resources and Environment.

Ecosystems provide numerous goods and services to human society, including harvestable fish and timber, water purification and nutrient recycling, as well as cultural services such as recreational and other nonmaterial benefits.

"Knowing the distribution of threats and benefits--the linking of ecosystem service maps with threat maps--is a powerful and under-utilized tool to help us better manage the Great Lakes and other highly valued ecosystems," Allan said.

A paper summarizing the study's findings is scheduled for publication Oct. 1 in Frontiers in Ecology and the Environment, a journal of the Ecological Society of America.

Allan and his team used data obtained from agency reports, citizen-science databases and social media for the years 2000 through 2010. Tourism and recreation data were obtained from the National Oceanic and Atmospheric Administration for 78 coastal U.S. counties around the Great Lakes.

The NOAA data showed that $15.4 billion in gross domestic product was generated within the shoreline counties in 2010, with tourism and recreation accounting for $8.3 billion of the total. With help from NOAA economists, the U-M-led team showed a strong correlation between all five recreational activities and the tourism and recreation portion of the gross domestic product for coastal communities.

The researchers found that the most intensive use of the five recreational resources occurred, not surprisingly, near cities and across the southern portion of the Great Lakes region.

Locations where both environmental stress and recreational opportunities are above the county median occur mainly around Lake Erie and Lake Ontario. Much of the U.S. shore of Lake Erie falls into this category, which may surprise many who view the shallowest Great Lake as having lost much of its value.

The researchers say the co-occurrence of high environmental stress and high rank in recreational benefits is a conundrum that calls for further research.

"It's possible that these highly stressed locations will deliver even greater benefits if stress is reduced, but it is also possible that these locations are highly resilient," said Peter McIntyre of the University of Wisconsin, one of the study co-authors and a member of the original stress-mapping team.

"We need studies that track restoration activities and measure not only whether stressors are reduced, but also whether human benefits are realized."

Producing detailed maps of Great Lakes recreational use required imaginative approaches, said project co-leader Sigrid Smith of the U-M School of Natural Resources and Environment.

The team contacted state agencies to obtain a measure of sport fishing effort, measured as angler hours. Birding activity was acquired from a citizen science database maintained by Cornell University's Laboratory of Ornithology, where birders upload their observations.

Except at a few locations, no data are kept on beach visits, so the team exploited a method based on social media, capturing geo-referenced Flickr photo uploads from more than 800 beaches around the Great Lakes. To quantify spatial patterns in boating effort they counted boat slips at marinas, and data were available for visits to state and provincial parks.