This past February, TWI Senior Ecologist Dr. Gary Sullivan presented at the annual Wetland Science Conference organized by the Wisconsin Wetlands Association. He was invited to present because his 15 years here at the Wetlands Initiative have given him an unparalleled perspective on the conference’s 2018 theme: restoring wetlands to mitigate and withstand the effects of climate change.
For as long as TWI has been working to restore sites to ecological health, we’ve also been gathering detailed data on how each of our sites changes from year to year, season to season. Over the years, we’ve used that monitoring data to develop tactics to ensure our own restoration projects are resilient and sustainable. At the conference, Sullivan got a chance to share this timely research with others in the field, using TWI’s Lobelia Meadows restoration at Midewin National Tallgrass Prairie as a case study.
It may seem like common sense, but long-term management of restored sites based on continued monitoring, called “adaptive management,” is a pretty recent innovation. In the early days of ecological restoration, Sullivan explained in his presentation, many practitioners used a “set it and forget it” model: They pulled up invasive weeds, sowed seed of some native species, and let nature sort it out—not always the recipe for a biodiverse and resilient restored ecosystem. In contrast, the ongoing monitoring that has shaped the success of TWI’s Lobelia Meadows project is a model for what will hopefully become a larger trend in the restoration world.
TWI has been partnering with the U.S. Forest Service on restoration at Midewin National Tallgrass Prairie for more than 15 years. Lobelia Meadows is our most recently completed parcel at this 20,000-acre site near Joliet, Illinois, formerly a U.S. Army arsenal. Crisscrossed by roads, drain tiles, and earthen berms, Lobelia Meadows had been home to the arsenal’s sewage treatment plant. These complexities made it more than a fair challenge for our restoration team.
After the infrastructure that had drained the land for years was removed, Sullivan and his TWI colleagues installed 12 wells in a grid pattern across the site. With these wells, the team would be able to track changing water levels from season to season and year to year, to measure the effects of the hydrologic restoration over time.
Sullivan and his team also took pre-restoration soil samples from across Lobelia Meadows to identify rare dolomitic zones for the reintroduction of extremely range-restricted and often endangered plants, like woolly sedge and leafy prairie-clover. Using the soil data, they then planted appropriate species across the parcel and, over the next several years, tracked changes in metrics like native coverage (the area where the species are growing) and the floristic quality index (a measure of an area’s diversity of native plant life).
Thanks to constant monitoring we’ve been able to accurately assess how much Lobelia Meadows has changed since restoration began, and make adjustments as necessary. Between 2012 and 2015, wetland areas at Lobelia Meadows increased 513%—much more than Sullivan had anticipated. Between 2012 and 2016, there was a 268% increase in native plant cover and a 207% jump in the floristic quality index—both indications that the restoration is progressing in leaps and bounds.
Sullivan’s data has also shed light on the reality of climate change in the Great Lakes region. In 2010, ideal conditions for planting native plugs (seedlings raised in greenhouses) ranged from mid-May to mid-July. In 2017, in contrast, conditions were right for planting far earlier, in April, and TWI’s field staff rushed to get plugs in the ground while the warm, wet weather lasted. By June the plug-planting window had closed and conditions were too hot and dry.
Similarly, ideal conditions for seed sowing—the cold, wet weather of mid- to late winter—were mid-December to mid-February in 2009/10, shifting to a slim gap of mid-November to mid-December in 2016/17. This data isn’t firm statistical evidence of any larger trends but it has informed TWI’s restoration planning at Midewin and other sites, and farmers and restoration ecologists alike are dealing with shifting, unpredictable weather patterns across Illinois.
Fortunately, as Sullivan shared with other experts at the conference, there are techniques for creating restored prairie and wetland habitats that are resilient to climate change. A key practice is to bolster genetic diversity by sourcing plants from multiple areas. For all of TWI’s projects, Sullivan sources seed and plugs from a 100-mile radius of the site as well as species from slightly more southern latitudes. As conditions become warmer and wetter farther north, some of these more-southern species, though not present in our region’s pre-settlement ecosystems, should be able to thrive.
Sullivan emphasized in his presentation that not all plants are suited to being brought north, since many bloom and seed in response to changes in photoperiod (the amount of sunlight plants receive per day), which shifts seasonally with the Earth’s rotation. Because of differences in photoperiod from region to region, some plants from southern Illinois may bloom at the wrong time and struggle to survive farther north, even within the same state.
There is still much we don’t know about how climate change will unfold—and how it will affect ecological restoration. These unknowns make monitoring like TWI’s all the more critical. After all, Sullivan said during his presentation, “You can’t respond to problems you can’t see.”
Likewise, professional gatherings like the Wetland Science Conference become all the more valuable for sharing emerging knowledge with peers. While once restoration ecology was focused on reconstructing damaged ecosystems, the field now must figure out how to create ecosystems that will thrive in the context of a rapidly and unpredictably changing climate.
Learn more about Midewin National Tallgrass Prairie here.
Learn more about TWI’s monitoring results at Lobelia Meadows here.
Learn more about wetlands and climate change here.