The University of Wisconsin-Madison Arboretum was this year’s host of the annual Grassland Restoration Network workshop. The Fellows and I spent much of last week in Madison, along with about 120 other people from around the central part of the U.S. The crowd consisted mainly of people who are actively restoring prairies and/or evaluating the results. As a result, most of the discussions were very applicable to the work we are all doing at our home sites.
I came away from the meeting with a renewed sense of hope about prairie conservation and restoration. That is despite the fact that many of the presentations were sharing news of prairie degradation and population declines. After I share some of the messages we heard and my sunny interpretation of them, you can decide whether I’m optimistic or delusional.
Brad Herrick of the Madison Arboretum shared the story of Faville Prairie, a wet prairie remnant that was severely flooded in 2008. During June of that year, the site remained under high water for several weeks. In 2010 and 2011, scientists re-sampled some old permanently-marked vegetation plots to see how the plant community had changed. The plots were originally set up and sampled by Max Partch in the 1940’s and then sampled again in 1978-79. Of course, it’s impossible to know how much the prairie had already changed prior to the 2008 flood, but it seems reasonable to expect that the unprecedented high water was a big factor in the results the botanists found in their 2010-11 sampling.
After the water receded, the site looked sad and dead, but plants came back quickly and re-filled the barren landscape. Some species, however, were less abundant than before. The average number of plant species found within the 4m square plots decreased from 24.2 to 20.5 and a few species, including prairie blazing star (Liatris pycnostachya) and shooting star (Dodacatheon meadii) were not found at all, despite having been common before. Other species, including prairie dock (Silphium terebinthinaceum) and prairie dropseed (Sporobolus heterolepis) also declined significantly in abundance. In contrast, the invasive reed canarygrass (Phalaris arundinacea) expanded the size of its kingdom in the portion of the prairie nearest the river.
On the second day of the workshop, Amy Alstad, with the Driftless Area Land Conservancy, presented results from her PhD project, in which she also used “legacy data” to examine changes in prairie communities over time. In her case, she surveyed 47 prairies that had first been studied in 1950 by John Curtis and then re-surveyed again in 1987. Amy went out in 2012 and inventoried the plant species in those same sites (and then went out to some of them again in 2015 to be sure the 2012 drought wasn’t a factor in her results).
The plant communities in those 47 sites had changed quite a bit between 1950 and 1987, but Amy found that they had changed even more dramatically between 1987 and 2012. Some species were added to the sites (including invasive species) but others disappeared, especially those that are rarely found outside of high-quality remnant prairies. The average number of plant species found at each site wasn’t significantly different between the three sampling periods, but the trajectory of change at many of the sites isn’t good.
In addition to those plant community presentations, we also heard from Karen Oberhauser and Susan Carpenter about monarch butterflies and bees, respectively, as well as the conservation needs for those insects. Monarchs, of course, are much less abundant than they used to be, and many bee species have experienced big population declines. The massive loss of habitat, especially prairies with high plant diversity, are driving those population declines, with fewer milkweed plants (including in cropland) playing an additional role in the crash of monarch numbers.
Cheery news, right? You’re probably wondering how I came away from these presentations and the overall workshop feeling anything but depressed. I agree that much of the news wasn’t great, but let me give you a little more context.
First, in Brad’s talk about the flooded prairie, I found it inspiring that after weeks of complete inundation, the Faville Prairie plant community rebounded quickly. Despite big changes (of course) in the composition of the plant community, it was still a prairie, and still had the majority of its plant species. That’s pretty amazing! Yes, reed canarygrass is a major threat, but it’s a major threat in most wet prairies everywhere. Its increased footprint was probably a foregone conclusion.
The vast majority of plant species survived the flood, and there’s a good chance that the species that didn’t (or were greatly reduced in abundance) will be able to recolonize over time. That chance is increased significantly by the fact that the Faville Prairie is at a site where Madison Audubon and others are working hard to restore surrounding cropland back to diverse prairie vegetation. They already own 670 acres of land nearby, including several parcels directly adjacent to Faville Prairie. We toured several of their restoration projects, and they look wonderful. Increasing the overall size of the prairie footprint in that area will increase the population size and viability of prairie plant and animal species and might allow species eradicated by the flood to recolonize Faville Prairie.
Amy’s results were disheartening, of course, and even more so because only 47 prairies could still be re-surveyed out more than 200 that Curtis has looked at back in 1950 (most no longer exist). However, despite the small and isolated nature of the prairies in her study, many of the prairies she looked at are still in pretty good shape – including some that were identified in 1950 as the best remaining examples of Wisconsin prairie. In addition, Amy identified two factors that were tied to the sites that had best retained their plant diversity and conservative species. The first was regular application of prescribed fire, and the second was the size of the prairies and surrounding prairie habitat (including restored prairie). In other words, prairie management and increasing prairie size through adjacent restoration work makes a big difference in the survival of small prairies. That isn’t a message of despair, it’s a call to action. We’ve got a good chance of saving the remaining prairies if we do what we already know how to do – manage them carefully and rebuild their size and connectivity.
Along those lines, Mike Hansen of the UW Arboretum showed us some photos of recent successful restoration projects at the arboretum itself. In particular, they have working on sites where prairies and savannas have been severely encroached upon by trees and brush. After removing the invading woody vegetation, Mike said they were seeing amazing recovery by prairie plants that hadn’t been seen for years. In some cases, they added seeds of missing species and were seeing positive results from that work as well. Again, management leads to successful conservation results, and the resilience of prairies is aiding our conservation efforts.
Pollinators, including thousands of bee species, along with many others like monarch butterflies, are certainly struggling today. On the other hand, the fact that many of those species have managed to hang on as long as they have is pretty incredible. Wisconsin’s prairie footprint has decreased from 2.1 million acres to less than 10,000. Illinois also has less than 10,000 acres of remnant prairie left, and in both states, the majority of the remaining fragments are tiny. (For comparison, each of the two bison pastures at our Niobrara Valley Preserve is about 10,000 acres, and they are set within 12 million acres of intact Sandhills prairie. Unfortunately, while Sandhills prairie has some of the same species found further east, its survival doesn’t make up for the loss of tallgrass prairie.)
Thoughtful management of remaining tallgrass prairies and restoration of adjacent sites to increase prairie size can make a big difference in pollinator conservation. So can increased use of native plants in urban and suburban landscapes, increased numbers of milkweed plants, and more judicious use of pesticides. We know how to do all of that and are making progress in many places. I was impressed and energized by the quality of restoration projects we saw in the Madison area last week. As the size of restored prairie landscapes increases, so will their value to pollinators and other animals. In larger prairies, managers will have more opportunities to manage for more varied habitat structure (height and density of vegetation) to better accommodate the needs of birds and other prairie species that rely on that habitat heterogeneity.
Look, I’m not saying we aren’t facing massive challenges in prairie conservation. Of course we are. Most of our prairie is gone, especially in the tallgrass region, and much of what’s left is in small and isolated remnants, threatened by invasive species, climate change, and other dangers. On the other hand, our knowledge of how to restore and manage prairies is sophisticated, and we can point to successful projects in many places. Most importantly, prairies and their species have shown themselves to be amazingly resilient, despite the catastrophic shocks they’ve been subjected to. That resilience buys us time – more than we deserve, probably – to save what’s left.
Having said that, the main obstacle blocking the success of prairie conservation is not climate change or invasive species, it’s the lack of public support for prairie restoration and protection. While it’s important to continue restoring and managing the prairies we have left, those efforts will only lead to success if we convince others that prairies matter. Rather than hanging our heads and bemoaning the continued degradation of grassland habitat, let’s get out there and share the stories of the beauty, diversity, resilience, and importance of prairies!
The Prairie Ecologist 