August 10, 2016

Researcher analyzes natural ecosystem benefits

by Andrea Hahn

CARBONDALE, Ill. -- If conservation is important, there must be a reason for the importance, a demonstrable value that goes beyond mere aesthetics. Southern Illinois University Carbondale graduate student Mark Healy is focusing his research on describing that value in practical terms, of finding ways to measure how natural ecosystems benefit society and individuals and why conservation is worth the trouble. That field of study is called “quantification of ecosystem services.” 

Healy earned his bachelor’s degree and continues his studies in the Department of Geography and Environmental Resources at SIU. Like many in his field, he has a fierce desire to protect natural environments and to find ways to lessen the harmful effects of human populations. But he knows not everyone agrees that conservation for its own sake has value. 

“I like to think that if I am going to make a difference in real world applications in the field I am working in, the quantification of ecosystem services is a promising means to do so,” Healy said. “Regardless of ideological leanings in regard to the environment, people can agree on decisions that potentially reap the greatest net benefits to society as a whole.” 

Healy said he believes ecosystem service quantification – proving a demonstrable, practical and economic value to ecological conservation – is crucial to successful and sustained conservation movements. Conservation activity foisted on people against their will or without their consent won’t have staying power, he said. 

“Many who are proponents of environmental conservation and environmentalism in general tend to appeal to society’s conscience to coerce support,” he said. “I consider it more pragmatic to appeal to society’s well-being. We live in a democratic society with varying ideologies -- if we can’t show how protecting the environment contributes to tangible societal benefits, then, to many people, it is an aimless cause.” 

As an undergraduate at SIU, Healy conducted research on sediment loss in the Big Muddy River Watershed. Sediment loss is a good place to start to make the argument that conservation practices may have practical value. Soil erosion costs Americans as much as $40 billion every year. The costs accrue from degraded farmland and from water treatment costs that escalate as sediment enters a body of water. It also causes increased risk of flooding, decreased water recreation due to poor water clarity and damage to wildlife habitat. 

Healy used geographic information system (GIS) modeling tools to measure and predict sediment loss. He examined and compared different potential land use and management scenarios to measure those that might be effective to curb sediment loss and provide a clear benefit to area residents. 

The Big Muddy is a water system of considerable local importance -- the watershed spans 11 Southern Illinois counties. Healy focused on it for that reason and also because damage from sediment to lakes and streams, including Rend Lake and Crab Orchard Creek, within the watershed is wide-spread, according to a report from the Illinois Environmental Protection Agency. 

Healy’s study suggested that woody wetland and forest land-cover contributed to sediment retention and decreased soil erosion. In his study, soil loss was highest at Galum Creek, which is an area characterized mostly by cultivated crops and pasture. Soil erosion was also high at the Middle Fork of the Big Muddy, and at Beaucoup Creek -- again, both areas with considerable farm and pasture land in the watershed, but also some forest. Potential soil erosion was lowest at Crab Orchard Creek and low at Cedar Creek-Big Muddy River watershed, Kincaid Creek and Casey Fork. All of those sites are characterized by more forest than pasture and cropland, and by considerably more pasture than crops. 

Healy concluded that deforestation contributes significantly to soil erosion in the Big Muddy watershed. To reduce soil erosion, then, he explained, don’t cut down all the trees. In addition, mixed use of agricultural land, such as incorporating pasture with crops, may reduce erosion in the watershed area. 

Healy suggests that a tree break or margin of forest near watershed areas will help keep cropland soil in place, where the farmer wants it, and out of the watershed. Other practices that might contribute to the same goal -- less erosion -- might include no-till farming, cover crops between harvests and agricultural terracing 

A follow-up study of a block of agriculture land restored to its historic wooded wetland condition south of Rend Lake suggested a similar conclusion. 

Healy earned a prestigious Master’s Fellowship Award to continue his work at SIU. His research activities in the immediate future will focus on the quantification of ecosystem services from levee setbacks and other floodplain strategies in the Illinois River basin.