Report from the 2013 Grassland Restoration Network Workshop – Part 1

The Grassland Restoration Network’s annual workshop took place a couple weeks ago in Columbia, Missouri.  This year’s workshop was hosted by the Missouri Department of Conservation and included more than 90 people from around the country.  As always, the meeting was a mixture of presentations, discussions, and field tours, and was informal enough that we had plenty of time to get to know each other and catch up on what everyone has been learning at their own sites.  There were too many topics and discussions from the workshop to cover in a single blog post, so I’ll spread them out over the next several weeks or months.

Attendees of the Grassland Restoration Network's annual workshop at Tucker Prairie, east of Columbia, Missouri.

Attendees of the Grassland Restoration Network’s annual workshop at Tucker Prairie, east of Columbia, Missouri.

One of the most intriguing discussions of the workshop was an extended conversation during our field trip to the 711 acre Prairie Fork Conservation Area, managed by Missouri Department of Conservation (MDC).  At several points during the trip, we talked about objectives for restoration projects and prairie plantings.  Here in the Platte River Prairies, our restoration objective is to use prairie plantings to enlarge and reconnect fragmented remnant prairies – hoping to increase overall ecological resilience and the viability of populations of plants, bees, etc.  At Prairie Fork, however, there are no remnant prairies to stitch together, and education is a major focus of their restoration project.  Their stated restoration goal is simply to rebuild natural communities and their processes.  Then they use those restored areas as platforms for their education work.

Although Prairie Fork Conservation Area is not far from Tucker Prairie – the last remnant of the once vast Grand Prairie that stretched across a large swath of Missouri – MDC staff are not trying to design their plantings to mimic Tucker Prairie.  Instead, they are harvesting seed from Tucker prairie and other small scattered areas of native prairie vegetation to create seed mixtures that are a composite of all of those sites.  As a result, prairie plantings are allowed to develop into communities as local site conditions allow – a very sensible approach.

Rattlesnake master is common at Tucker Prairie, the last sizeable remnant of the Grand Prairie that used to cover a large portion of northern Missouri.

Rattlesnake master is common at Tucker Prairie, the last sizeable remnant of the Grand Prairie that used to cover a large portion of northern Missouri.

The decision not to impose constraints on what each Prairie Fork planting needs to look like gives MDC considerable freedom in terms of evaluating success.  That freedom led to some great discussions about what success should/could look like.  There were three tour stops where the topic came up in some form, and each is worth discussing.

1. The first discussion occurred early in the tour when we were looking at a soybean field that was going to be converted to prairie vegetation within the next few years.  Around the edge of the field were “waste areas” of tall fescue with infestations of sericea lespedeza, autumn olive, and other invasive plants and trees.  Because of the trees and topography, it wasn’t feasible to put those areas into cultivation, which is the technique MDC (and most of us) would prefer as a way to create a clean seed bed prior to planting prairie.  The group starting talking about other ways those areas might be prepared for planting, until Bill Kleiman (with The Nature Conservancy’s Nachusa Grasslands in Illinois) abruptly shifted the discussion.

Bill made the excellent point that those difficult areas wouldn’t necessarily have to be converted to a diverse prairie planting, and that attempting to do so might prove to be overwhelmingly time consuming or simply impossible.  The seedbank of invasives in those areas is probably heavy enough that even multiple years of cultivation might still result in long-term fights with invasive plants emerging from that seedbank long after prairie vegetation was planted.  Instead, Bill suggested, why not implement an annual program of broadcast herbicide spraying in those waste areas – with the simple goal of maintaining them as a low diversity, grass-dominated, plant communities that won’t threaten nearby diverse plantings?  In other words, rather than trying to make those areas perfect, just make them harmless.  Down the road, when everything else is restored, MDC can always come back and spend energy trying to convert them to something diverse.  In the meantime, they can save a lot of time and energy by avoiding a (likely fruitless) battle to convert a very weedy area into a pretty prairie.  It was certainly an interesting proposal.

Rosinweed (Silphium integrifolium) was just beginning to bloom during the GRN workshop.

Rosinweed (Silphium integrifolium) was just beginning to bloom during the GRN workshop.

2. The next site we visited had been planted to prairie vegetation several years earlier, but had a chronic infestation of sericea lespedeza.  While MDC staff was controlling the lespedeza through spot spraying, there was enough lespedeza (and enough spraying) that the area’s plant diversity had become fairly limited and dominated by a few grass and wildflower species.  Chris Newbold, who had been in charge of the restoration work at the time the site was seeded, said that if he had to do it all again, he would have left the area in cultivation a few more years to get better control of the lespdeza population prior to planting.  The more pressing question now, though, was how to deal with the site going forward.  Options included starting over by returning it to cultivation, trying to overseed the area to establish better plant diversity, or just leaving it alone.  An additional proposal was to overseed with plant species that are resistant to a selective herbicide that controls lespedeza, allowing the site to be broadcast sprayed without eliminating all plant diversity.  I don’t think the question was resolved through our discussion, but we built upon our earlier conversation by posing the question, “Does every part of a restoration project have to be ‘perfect’ in order for the project to be successful?”

This portion of Prairie Fork Conservation Area was seeded with a high diversity mixture but has lost plant diversity , at least in part because of years of herbicide spraying for sericea lespedeza.  The lespedeza is spot sprayed, but is abundant enough that herbicide impacts are evident on the plant community.

This portion of Prairie Fork Conservation Area was seeded with a high diversity mixture but has lost plant diversity , at least in part because of years of herbicide spraying for sericea lespedeza. The lespedeza is spot sprayed, but is abundant enough that herbicide impacts are evident on the plant community.  Mike Arduser, of MDC, pointed out that the site looks really nice from a bee habitat standpoint, bolstering the idea that although it had lost some of its plant diversity, it was still an important contributor to the landscape around it.

I appreciated the discussion because it forced me to reflect upon our Platte River Prairies, and areas that I wish looked better than they did.  In both my prairies and at Prairie Fork, it’s really the big picture that’s important.  Within the mosaic of natural communities that make up any sizeable prairie, it’s probably ok to have areas of low diversity vegetation.  At least at the scale of Prairie Fork, it’s really the mosaic that’s important, and variation in plant species composition between individual portions of the landscape is not only acceptable, but preferable.  Coming to terms with the idea that it’s ok to have portions of our prairies/properties that are less diverse than we think they could be is an important part of being a successful land manager.  The alternative probably entails driving ourselves to exhaustion!

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3. The last site we looked at was a 2004 prairie planting that was very diverse and full of big showy wildflowers.  From an aesthetic standpoint, the planting was a big beautiful success.  I asked the MDC staff how they might judge the success of such a planting according to their objectives.  Clearly, one part of the answer is that a showy prairie is useful in terms of getting people to appreciate prairies – so that fits well into education/outreach objectives.  However, Jeff Demand, the current site manager, had another interesting perspective.  Jeff said that he appreciated the planting because it required very little maintenance.  There were no real invasive species issues to deal with, and nothing else about it that screamed out for attention.  The planting was clearly of value to wildlife, pollinators, and other prairie species, but it was particularly nice to have an area that just needed some period burning or similar management.  Especially when budgets and staffing are tight (and when are they NOT?) a site that is attractive and low maintenance can seem like heaven.

This 1994 seeding at Prairie Fork is an aesthetically-pleasing site.  Most people would be very happy to have this kind of establishment success from a prairie planting.

This 2004 seeding at Prairie Fork is an aesthetically-pleasing site. Most people would be very happy to have this kind of establishment success from a prairie planting.  However, aesthetics is not always the best measure of success.

There are no right or wrong answers when it comes to objectives.  Every site has its own, and they almost always change over time.  The important thing is to know what the objectives are for a particular site, and to be measuring whether or not you’re moving in the right direction.  It’s always nice to hear about other people’s objectives and measures, because it makes us re-examine our own.

I tend to worry more than I should about portions of our site that aren’t as “nice” as I think they should be.  The field trip discussion was a great reminder to sto obsessing about small areas and keep the big picture in mind.  It’s important to deal with areas that might negatively influence the surrounding landscape (e.g., by providing a foothold for invasive species that can spread into nearby areas).  Otherwise, however, variation between portions of a prairie or prairie landscape just adds to the diversity – and resilience – of the ecosystem.  I think that’s a good thing.

I guess I just have to be reminded of that now and then.

Prairie Response to Grazing and Drought

Fire, grazing, and drought are the three dominant forces that shape(d) our prairies over time.  Because of the drought we experienced last year, many of our prairies experienced all three of those forces in the same season.  We manage most of our sites with variations of patch-burn grazing.  After we burn a portion (patch) of prairie, cattle concentrate their time within that burned patch, grazing it much more intensively than other portions of the same prairie until a new patch is burned.  As a result, the dominant grasses are much weakened by the end of the season, temporarily opening space for opportunistic plants of many species.

Showy evening primrose is prominent among a number of profusely blooming plants in this restored prairie that was burned and intensively grazed during last year's drought.  The Nature Conservancy's Platte River Prairies, Nebraska.

Showy evening primrose is prominent among a number of profusely blooming plants in this restored prairie that was burned and intensively grazed during last year’s drought. The Nature Conservancy’s Platte River Prairies, Nebraska.

The patch of prairie in the above photo is not being grazed this year, which will allow the dominant grasses – still present, but much reduced in size and vigor – to recover.  In the meantime, butterflies, bees, and other pollinators are enjoying an abundance of “weedy” flowers such as hoary vervain (Verbena stricta), showy evening primrose (Oenothera rhombipetala), yarrow (Achillea millefolium), upright prairie coneflower (Ratibida columnifera), black-eyed susan (Rudbeckia hirta), and many others.  At the same time those pollinators can still find their regular fare of more “conservative” long-lived perennial forbs (prairie clovers and other legumes, perennial sunflowers and silphiums, etc.) – they are just visually obscured by the species responding positively to last year’s grazing and drought.  If you’re interested, you can see some plant data from this site from a couple years ago that shows some trends in species frequency and floristic quality over time.

Here’s another photo of the same patch prairie, showing the diversity and abundance of opportunistic wildflower species and a thin, weakened (temporarily) stand of grass.

Another shot from the same prairie as above.

Another photo from the same prairie.

One of the aspects of fire/grazing management I enjoy most – and one that can make some people uncomfortable – is the variability in prairie response between years and between sites.  Every time we burn/graze a prairie, we see somewhat different responses from the plant community, even if we’re using very similar timing and stocking rates each time.  I think that’s great, and that it adds to the kind of messy, dynamic diversity I think is important in natural systems.  That messiness helps prevent any species or group of species from becoming too dominant, but also helps ensure that each species has the opportunity to thrive and reproduce now and then.

Griffith Prairie (owned and managed by Prairie Plains Resource Institute of Aurora, Nebraska).  The area shown in this photo was burned and grazed during the drought of 2012 in a way very similar to the prairies shown earlier.  However, the plant community response at Griffith was very different - including a big flush of deer vetch (Lotus unifoliatus) and abundant reproduction of leadplant (Amorpha canescens).

Griffith Prairie (owned and managed by Prairie Plains Resource Institute of Aurora, Nebraska). The area shown in this photo was burned and grazed during the drought of 2012 in a way very similar to the Platte River Prairie shown earlier. However, the plant community response at Griffith was very different – including a big flush of deer vetch (Lotus unifoliolatus) and abundant reproduction of leadplant (Amorpha canescens), among other things.  Visually, the prairie is very flowery this year because the vigor of the dominant grasses is suppressed from last year’s drought/grazing.

These days, I spend quite a bit of time thinking about the scale and arrangement of our management treatments across the landscape.  For example, I’m not sure how big each of our within-prairie habitat patches should be.  I don’t think it matters much to plants, but habitat patches have to be large enough for animals to live in, yet small enough that wildlife and insects don’t have to travel unreasonable distances to find appropriate habitat when conditions change from year to year.  For example, voles living in a thatchy patch of unburned prairie will have to relocate when that patch gets burned.  How far can they travel to find another patch of unburned prairie?  What kinds of habitat do they need as they make that trip?

For now, we’re just doing what seems reasonable, but I’ll feel better if we can get some data to help us better evaluate the travel abilities of insects, snakes, small mammals, and others.  Anybody looking for a career’s worth of research projects?