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Thursday, February 15, 2018

Planning Notes Updated: 2014 to 2018

This post is intended for people who are interested in the details of ecological restoration. It consists of five “cases” – with photos that exhibit problems or opportunities and comments on possible solutions.
The initial "Diagnoses" and "Prescriptions" were written in 2014.
In 2018 we comment on what we've actually done and learned since then. 

First, a definition of a word used often below:
conservative – a species that is most common under long-evolved natural conditions – and rarely is found away from them. In fine prairie remnants, the conservatives are among the most common plants. In most “restored” or degraded prairies, they are rare or non-existent. A more detailed note on conservatives is at the end of this post.

Case 1

Diagnosis: Weeds here are under control. Yet few conservative species are established. Most of what’s here are short termers – species likely to mostly give way to others, for better or ill, before long. The early goldenrod, for example will likely be replaced excessively by big bluestem (present now in small numbers) if nothing is done but burn.

2014 Prescription: Broadcast seed of conservative species. Especially important are little bluestem and prairie dropseed – to head off the big bluestem. One place to sow seed of conservative species is the denser early goldenrod areas. These areas are ready. 

2018 Comment: We do some of this, but not enough. We haven't sufficiently remembered this good advice at seed-gathering and seed-mixing time. We need to map opportunity areas more carefully this summer, plant some and hold back some as controls, and monitor the results. We are putting the needed mapping and seeds goals on our 2018 summer and fall priorities calendars.

Case 1A: close-up of a different part of area 1

Patches like the one shown above strike me as receptive to our most-prized conservative seed. There is currently little aggressive tall grass here. The commonest plants shown (early goldenrod, black-eyed Susan, fleabane) are among the quickest to move out of the way for quality species. Sow such classy species as cream false indigo, Leiberg’s panic grass, white and purple prairie clovers, prairie dropseed, alumroot, shooting star, prairie gentian, yellow stargrass, prairie cinquefoil, etc.

However, if you look closely at the photo above, you'll see quite a bit of gray dogwood and grape. Shrubs and vines may be holding this area back, especially if it doesn't get burned frequently. Woody plant shade may be progressively killing off most seedlings in most areas until the next burn - at which time the whole process starts over with more fleabane etc. Perhaps we may want to laboriously cut and herbicide those prairie-killing shrubs. Or perhaps you we to schedule this plot for annual burns until a more competitive herb flora wins out.  

2018 Comment: We've watched this area and are more impressed than ever that "burn-off-and-regrow" shrub dynamics are ruling this area. Is that a good or bad? Certainly shrub dynamics are a component of the savanna dynamic. But are we missing half the species here that once made up that dynamic? Some say the principal shrubs were hazel and oak. Perhaps the grasses and forbs that grew with them in this context aren't here now. And if so, is this now just a "retarded" weedy area that's stuck? We should install a transect of permanent plots and monitor plants here over time, to see if this area is changing, and how. Then we'll be better equipped to decide whether some change in protocols might improve it.

Case 1B: close-up area 2

This patch shows quite a bit of young big bluestem, dense patches of mountain mint, young ash trees, and dogwood shrubs. A patch like this may be less prime for conservative seed. Given how little seed we have of the high conservatives, we might want to seed this area sparingly. Perhaps it’s a place to add somewhat aggressive species like rattlesnake master, prairie dock, and compass plant – to increase the diversity of niches that the high conservatives will use to gradually become established from better areas nearby over the decades.

2018 Comment: Yeah, fine, 2014 commentator. But we really don't know the answer unless we monitor with permanent plots. Tom Vanderpoel assures us that prairie clover and shooting star will help break down dense big bluestem areas over time. Yes, we've seen that too. We've also seen areas where the bluestem resists other species for, it seems, decades. We would benefit from more permanent monitoring plots in seeded areas of dense big bluestem, mountain mint, tall goldenrod, and other resistant areas, to see what species might do best there.  

Case 2

Here two high conservatives dominate (purple prairie clover and prairie dropseed).  Early goldenrod (which was dominant here years ago) has retreated to the frequency you might expect in stable, high-quality grassland. Although we see a little rattlesnake master, compass plant, and rough blazing star – the overall diversity seems low. It might not work so well to sow the high conservatives of mid-summer here; the competition could be tough to overcome. Perhaps this is a place to sow spring species such as prairie betony, shooting star, and cream false indigo, which might then open up more niches.

On the other hand, this area is currently a great seed source for dropseed and prairie clover, so perhaps there’s no need to do much here in the short term. The best next step could be a variety of little inter-seeding experiments. First, find out which species will compete against these conservatives – before investing a lot of seed in an area, which might be slow to accept it. 

2018 Comment: Ahh, yes. More experiments. Good ideas. So many plants and plots, and so little time.

Case 3
Two big questions here:
First, what do we do with the new planting shown below? It has good wildflower diversity but is weak on grass (and thus, unstable). As we study the vegetation that's emerging from the first seedings here, it’s hard to know whether this plot wants to be more mesic or wet-mesic overall. we’re thinking that we should especially sow dropseed and little bluestem in the drier parts – and switch grass and Dudley’s rush in the wetter parts. (At Somme, Dudley's rush seems especially common in many of the highest quality wet-mesic areas and is an especially "works-well-with-others" plant, that many conservative and endangered species thrive in when their seeds are broadcast.) 
But, second, perhaps the biggest question here is what to do with all those trash trees in the background. This whole area was so dense with buckthorn that essentially no grasses or wildflowers survived. But in the foreground area, a grassy turf survived with only scattered invading trees, and when we cleared them, an on-the-way-to-quality seems to have come back. But under the large numbers of ash, cherry, elm, and box elder trees in the background, the quality is still poor. Strategically, it would take too big a big chunk of our volunteer time to cut and burn them. But there’s now no sensible community to try to restore on the former prairie or savanna land underneath them. So our short-term strategy has been to plant natural species that may keep out the invasives and then wait until we have more time or a better answer. If you look closely, you may be able to see brown leaves on some of the trees to the right. That’s where fire singed some of the branches. Maybe fire will do most of our work for us here, over time, while we invest our resources on other areas where the prescriptions are clearer.

2018 Comment: since 2014 we've cut a few big basswoods and box elders out of that wooded area and spread a bit more "Intermediate" light-level seed. Mostly we've ignored the area except for being happy that the burns have carried through at least some of it. Our impression is that vegetation diversity and conservatism is improving. But we have no monitoring transects here. It continues not to seem like a big priority, for now. 

Case 4 
            The above patch of scarlet oak savanna seemed to be getting increasing diversity and quality – until recently.
            Around the tree on the right, notice wild quinine, butterfly weed, ox-eye sunflower, big bluestem, wild bergamot, rattlesnake master, and others.
            Then woodland sunflower (Helianthus strumosus or perhaps hirsutus) started wiping out much of that diversity. Perhaps this is a temporary stage, and diversity will come back? Or perhaps this sunflower is helpfully erasing species that aren’t so well adapted here, which will then be replaced by better-adapted species, if we broadcast their seed.
2018 Comment: In many areas, depauperate patches of woodland sunflower are spreading. It seems worth our time to monitor these areas to get to understand them better – and experiment by inter-seeding likely associates, if we can identify good candidates. (Check out lists of associates. The old Swink and Wilhelm was little help, but the new "The Flora of the Chicago Region" by Wilhelm and Rericha seems to have a lot more to study.)
Case 5 
Diagnosis: About half the trees in the center isolated grove shown above are dead. Some died from fire and others from Dutch elm or Emerald ash borer diseases. The few oaks are fine. Because we hadn’t had time to focus on it, we’ve left this dying grove to “nature.”  Of course, “nature” isn’t happening here, and the result is an increasingly unsustainable weedy and brushy mess. It will soon be another buckthorn monstrosity if we let current processes continue.
Possible Prescriptions
            We might plant some of our precious mixes of rare grasses and wildflowers around the edge. One mix is designed for the "Intermediate" semi-shade of the edge. A "Woods" mix might compete well in the darker shade of the interior). That could help keep the buckthorn at bay, but it could also be a waste of seed and effort. Throwing rare seed into nasty buckthorn re-sprouts is a recipe for failure. Also, the Intermediate species that would grow there in the short term would not be adapted to the less shady conditions that are coming – as these mostly non-oak trees continue to die from disease and fire. Why waste rare seed that would have more payback elsewhere?
            Perhaps we could broadcast the seed of some of the easier-to-get semi-shade herb species in the shadier, inner, non-buckthorn areas. We'd hope that those species would seal the wound and ward off the brush? Perhaps. Or we could plant natural shrub-copse species in hopes to build another native shrub island that we could experiment with (much appreciated by the significant bird species that nest at Somme). 
            Or we could short-circuit the misery and cut the out-of-place trees this winter. That would seem easiest. We could then just plant the open savanna/prairie mix (as in the foreground here), which would then be easily sustainable with little added effort beyond regular burns. But we’re trying to restore the natural savanna here, and we already have more than enough of the “prairie” component. 
            We could plant hazelnuts and bur oak acorns and protect them from voles, rabbits, deer and fire in the early years. Perhaps some of the box elders and basswoods can for the next 15 or 20 years provide the amount of shade that oak and hazel will someday provide, and the community can transition gradually from non-oak to oak. This challenging area still needs a lot of observation, experimentation, and thought. 

2018 Comment: So here's what we've actually done. Nothing in the denser, interior parts. Discovered many possible components of a good shrub thicket around the edge (hazel, pussy willow, black haw, nanny berry, silky and gray dogwoods, bur and scarlet oak). We've cut back some of the dense buckthorn edge that was overwhelming these areas. We've caged one hazel from the deer. We cut one tall patch of buckthorn and planted plugs of two-year-old wild plum, ninebark, and indigo bush inside a large cage. In one wet edge, we cut the buckthorn and planted wet prairie seeds. But 90% of this mess is like it was in 2014. We progress. We learn. We hope.

Final 2018 Comment: This is how the Somme experiment works: We prioritize as best we can and keep trying to do what seems strategic. It's like that old juggler's trick of keeping a lot of plates spinning, and we run back and give a bit more attention to what seems to need it – except that, when we get some area or aspect right, it just keeps succeeding forever, as the world turns. And we stewards seem to be happier all the time as, more and more, rare bits of ecosystem thrive richly on their own. Year round, we walk through and notice new successes and opportunities. We smile inside and thank our lucky stars for the opportunity to do this wonderful work.

-            -            -            -            -            -            -            -            -            -            -  

... finally as promised ...

a longer note on ecological conservatives

In many ways, the main and most challenging goal of ecosystem restoration is to restore and maintain plentiful conservatives. If such plants and animals are diverse and common, all the others will be intermixed with them, and we will have achieved ecosystem conservation. Monitoring and analyzing the results according to floristic and animal quality is an important part of any conservation project or program.

In the most commonly used Floristic Quality Assessment system, conservativeness is ranked on a scale of 0 to 10, with 10 being the highest. Examples of Chicago-region plants in the 0 range include ragweed, annual fleabane, and common milkweed. Typical alien weeds like dandelion would also be given a zero rating if these ratings weren’t reserved for native species.

Examples in the 9 and 10 range include prairie dropseed, white prairie clover, fringed gentian, prairie gentian, cream false indigo, prairie lily, Leiberg’s panic grass, prairie cinquefoil, prairie sundrops, heart-leaved Alexanders, and the prairie white-fringed orchid. 

Conservative animals may or may not require conservative plants. But the ecosystem is less without them. Examples of conservative butterflies found by Ron Panzer to require conservative vegetation include the regal fritillary, Aphrodite, and the Edwards hairstreak. Birds of conservation concern may live for a time in large pastures of alien grasses. But they’ll live sustainably in large high-quality prairies.

Introductions to conservativeness and the Floristic Quality Index are at

Note to readers: We always appreciate questions and comments. Thanks. 

Saturday, February 10, 2018

The Somme Prairie Grove Experiment

DRAFT: February 23, 2018
Will be improved and updated thanks to reader comments.
An "easier reading" version, with photos, will appear later in the Vestal Grove blog.

The Somme Prairie Grove Experiment
Science and Conservation Summary

At Somme Prairie Grove, for nearly four decades, a team of staff and volunteers has worked to restore and conserve natural ecosystems with their hundreds of endangered or rare species. With the encouragement and mentoring of experts in many fields, we have carried out a wide variety of informal and formal experiments. Initially recognizing “prairie” plants in the most open areas, we soon recognized savanna as the original ecosystem for most of this site.

What would become the Somme experiment was launched in 1977 as the “North Branch Prairie Project” with goals and methods coached and mentored initially by Roland Eisenbeis, Chuck Westcott, Prof. Robert Betz, Ray Schulenberg, Dr. William Beecher, George Fell, Jerry Paulson, and many more over the years. At all stages, our work required authorization by Forest Preserve staff, but in early years we were encouraged to rely principally on Dr. Betz and Illinois Nature Preserves Commission staff for details of plans and techniques.

We were initially inspired by Dr. Betz’ writing:

“It is surprising how little is known about the natural world … In order to carry out meaningful research in this area, it is necessary to have relatively natural landscapes … to serve as standards to evaluate the changes that have occurred elsewhere and their effects on men and other biological organisms… Even if there were no scientific values in a prairie, its aesthetic appeal alone would warrant its preservation. It is one of our links with the past – a tie with the natural world. It seems immoral to destroy an integral and important part of the biological world from which mankind arose.”

From “What is a Prairie?” in “The Prairie: Swell and Swale.” 
Photos by Torkel Korling. Essay by Robert F. Betz. 1972.

Once Betz had become a principal advisor, we benefitted from detailed suggestions and exchanges about our ongoing work and his – some of which very much paralleled ours. For example, his initial focus was high-quality remnants. But experience with how challenged even the best ones were had moved him to restoring their quality and expanding their dimensions. In little cemetery prairies, he pulled weeds, burned, and moved seeds from the best remnant areas to degraded ones. Then a principal focus became expanding the high-quality few acres of the Gensburg-Markham prairie to hundreds of acres of adjacent land. His concern? The small populations of most plant and animal species that comprised most prairies were vulnerable to genetic, disease, and other problems while having reduced capacity for maintaining evolutionary fitness as hydrologic, climatic, rain acidity, and other conditions changed. So, for example, as we worked to remove invasives from the three acres of Grade A (very high quality) original prairie at the seventy acres of Somme Prairie, we spent a good deal more time working to expand into the rest of those seventy acres as well as into the adjacent 85 acres of Somme Prairie Grove.   

Our initial plan for Somme Prairie had been simple. Pull invasive weeds, cut invasive brush, and move seed from high-quality to depauperate areas. At Somme Prairie Grove, with much less remnant quality prairie, Betz encouraged us to gather seed from diverse nearby natural populations. Betz impressed on us his judgment that all prairies, even the best remnants, had been subject to degradation – most obviously in the loss of animals – but almost certainly in the loss of many plant species as a result of lack of fire, fragmentation, different patterns of grazing and other animal use, drainage, and other changes. He emphasized two ecosystem conservation strategies: first, save and restore health to the little high-quality remnants and, second, do our best to restore full diversity to larger prairie landscapes, where animals, fire, competition, evolution, and time would have the opportunity to restore a more complete and diverse whole.

Initially, we saw Somme Prairie as the remnant and Somme Prairie Grove (SPG) as the larger prairie landscape to which full diversity would be restored. To restore missing plant species, we found we could locate nearly all original prairie species in spontaneous populations within fifteen miles of the North Branch Prairies. Within a few years, we recognized that most of SPG was originally savanna[1] and began to look for savanna seed sources; we found them to be harder to locate than prairie and expanded our search area to 25 miles. Savanna remnants turned out to be even rarer and more subject to rapid loss of quality than were the prairies.

Thus, Betz, Eisenbeis, and other advisors encouraged us volunteers to begin an experiment[2], a specialized sub-set of the overall forest preserve experiment. We were – in the words of the Forest Preserves’ charter – “to restore and restock … such lands together with their flora and fauna as nearly as may be, in their natural state and condition …” We sought to assemble larger work crews and more focused expertise than were available for most preserves. We would record the work and the results, for comparison with differently managed areas.

Basic research questions

Through our ongoing discussions with Forest Preserve and Illinois Nature Preserves Commission staff along with Betz, Schulenberg, and many others, we had the sense that we were doing the “battlefield medicine” analog of ecosystem triage and first aid. Three basic research questions underlay our planning and work.

  • How well may a damaged ecosystem[3] recover, and how much apparently missing biodiversity will spontaneously come back in response to remedial care?
  • How much missing plant biodiversity can be re-assembled in a damaged remnant through restoration?
  • What is the impact of this restoration work on the animals?
Over the years, these three basic experimental questions led us to many sub-experiments and many ways of measuring the results, as described below, along with data, observations, and judgements based on these and other sub-experiments (more than can be described here) and plain “tinkering”.


Aside from a bit of weed pulling, which started in 1977, we began Somme Prairie Grove restoration in October 1980. In the early years, work was on a rotating schedule with other North Branch sites; volunteer crews of fifteen to twenty people worked at this site roughly once a month during the eighties and nineties. In later years, as resources increased, work here was two or three large-group “workdays” per month and additional small-group sessions. The patch size of our experiments reflected what a group could accomplish in three hours (typically a tenth acre or less). We initially sought to restore these “workday-sized plots” through rescuing from brush all the most promising-looking plant associations on the site and planting diverse seed where the brush had stood. Since the best examples were scattered, we soon had little centers of “biodiversity restoration” to study that included dry-mesic to wet prairie and savanna scattered over much of the eighty-five acres. It may have been significant to our results that we never changed (or “obliterated”) any one large area at once. All work was in small scattered areas, bit by bit, year after year.


Fire was the exception. On average, half the flammable parts of the site have been burned every year. Unburnable parts included non-oak thickets, weed patches (e.g. tall goldenrod), and areas that may have been too wet on burn days.

When we expanded burning from grasslands to the oak woodlands in 1983, we found that there was typically a non-burned zone in between the areas of dense grass and the areas of dense oak leaves. Thus the woodlands and grasslands tended to stay separate in many areas.

Brush control

From the beginning we prioritized work according to the quality of remnants. Initially, there were many isolated “old field” patches among the more extensive areas of brush and trees. We worked to rescue and expand areas of greatest quality along with any areas that retained flora not found elsewhere.

The site had, and still has, many (now seemingly inappropriate) tree species planted in an earlier era. Forest Preserve staff introduced such species as pine, birch, post oak, rock chestnut oak, chinquapin oak, silver poplar, black locust, honey locust and others. In most areas, the major problem species that we thinned included buckthorn, tartarian honeysuckle, green ash, white ash, and box elder.

Bur oak, Hill’s oak, and shagbark hickory seemed to be consistently the major species of the higher quality wooded areas. There were many old bur oaks but few other old trees. We prioritized protection of existing young bur oaks and cut away trees shading them, including Hill’s oak and shagbark hickory. But in most areas, for many years, we left most Hill’s oaks and shagbark hickories, watching to see how they responded to repeated fire.

All or nearly all the white oaks stood in plantation areas. (Large areas of natural white oaks occur to the less-fire-molded Somme Woods.) No white oaks at SPG were old. But we mostly did not cut or thin the white oaks as a) we had higher priorities, b) it seemed like too much work, and c) these areas were stable, not promoting the growth of noxious species, and increasingly became a good source of woodland seed (after we planted it where burning made good habitat under the oaks). We did control the white oaks where their shade was damaging high quality prairie or savanna remnants or recovery.

We gradually recognized the need to protect some shrub species, especially hazel and wild plum. Some shrub thickets are now quite diverse but do not seem to develop hoped-for sustainability under the influence of fire. 


Initially, we followed the guidance of Robert Betz, Ray Schulenberg, and Harold Rock[4]. We raked our seed mixes only into areas denuded by brush, after we cut the brush. We restored some other species by “plant plugs” or “rootlings” grown in greenhouses or gardens. In time we learned that we would get better results more easily from seed broadcast into turf areas that were being burned, and that became our standard method.

For any given area, we tried to broadcast our seed mixes for two or more years, because we found that some species would be established only in some plantings in some years. Our suspicion was that in non-establishment years, perhaps weather conditions or pest predation in the previous year resulted in poor quality seed, or perhaps weather conditions in the first growing season following planting were not favorable. Thus, repeat plantings in the same area over a number of years may have increased the likelihood of a larger number of species succeeding in a given area. We also suspected that the overall diversity benefitted from the scattered plot approach. Species planted in one plot had the potential to move into adjacent plots over the years. And many areas were never planted, so that the existing species mix there could evolve without sudden competition from the whole list of species in the seed mix, over time and according to its own unguided dynamics.   

Most of the species planted were already present on the site, but in small numbers. Although their genetic diversity may have been badly reduced, these species may have the advantage of surviving associated symbiotic bacteria, algae, diseases, invertebrate animals, etc. Species not surviving at Somme Prairie Grove but surviving across the railroad and river in Somme Prairie may in time have such associates restored by unaided dispersal. (One indication of this process is the appearance in Somme Prairie of a species, cream gentian, not originally found there but very common at Somme Prairie Grove. It originally appeared at Somme Prairie only along the entrance trail, suggesting that it was introduced in mud clinging to the footwear of people who visited both.) Species not surviving at Somme before our restoration efforts may have had some associates brought with the seeds in the chaff, which we included when broadcasting the seeds. But their associated species may be much reduced at this new site.

We later summarized our approach and gave details about our basic seed-mix lists in the Tallgrass Restoration Handbook[5]. We gather more than 200 species of seed annually and have more than a dozen different mixes according to how shady and how wet the various planting areas are. 

Special projects

There are and have been many sub-experiments – some aimed at solving various problems and some aimed at facilitating species or community recovery. We will not attempt to list them here, but a few are worth mentioning as examples.

We were initially counseled by our advisors (especially Betz and Schulenberg) that prairie seed could not compete against an established turf of weeds. Because we did not have the resources to plow up the weeds as they had done in their experiments, they encouraged us to grow young plants in greenhouses, to give them a good start, and then plant them in our degraded prairies. We did this with partial success in the early years and planted other seed in the bare dirt that was all that was left in some areas after we removed the invasive shrubs and trees. 

The belief that prairie seeds could not compete in turf turned out to be erroneous. It had just been assumed, and no one had checked. We tried various approaches, found that some worked, and published the results.[6] As it turned out, Dr. Betz had made similar experiments and found the same. One challenge of this approach is that it takes five or longer years for many species to become apparent. Using the plowed field method, big bluestem and many other species were robust after two years. On the other hand, many species, especially those typical to high-quality prairies, often failed to establish by that approach. But we found that “inter-seeding” into turf did establish them readily. The successful conservative species included shooting star, prairie betony, prairie dropseed, Leiberg’s panic grass, prairie gentian, prairie violet, cream false indigo, purple prairie clover, and many more.  

In early years, we laboriously incorporated the seeds into the dirt by tearing up the top inch to quarter inch of soil with four-pronged rakes. In 1993 we decided to test whether that was needed – or whether would it be sufficient to merely broadcast the seeds in the fall and let the freeze-thaw cycle work on them. We marked plots, kept careful notes, took random samples in both experimental and control plots, and found that prairie species established well in open “old field” turf by simple broadcast alone. We published the results of that study in “Restoration and Management Notes”[7].

Restoring populations of endangered plants
We had no expectation or intent when we started, but it turned out that strategic "intensive care" could revive populations of more than a dozen plant species on U.S. or Illinois Threatened or Endangered lists. See, for example, our reports on the eared false-foxglove at: and the prairie white-fringed orchid at: .

Caging species threatened by animals
We found some plant species of concern being badly depleted from some areas by white-tailed deer. "Sapling" oaks were one foot tall, because their tops were so often eaten by those same overpopulated deer.  We began protecting some of them with wire cages and found them increasing dramatically. In some cases, such species became common or robust enough that continued caging was no longer needed.

Edge hedge
In the early years, Somme Prairie Grove was badly torn up by vehicle recreation. We decided to stop cutting brush near the edges so as to promote a physical barrier to exclude vehicles. In time, the hedge also became an appreciated visual and sound barrier as well as a habitat for some animal species. We control female buckthorn to lessen berry-production and resulting reproduction on the site. In some areas we have made some progress in replacing buckthorn with shrub and tree species native to these habitats.

Vestal Grove transect
The stand of bur oak along a part of the southern border of the site is one of the first areas of the Midwest where efforts have been made to restore full plant diversity to a “closed savanna” or “oak woodland” ecosystem. Initially, little grew under the oaks other than dense buckthorn. We burned for two years and watched for signs of understory recovery. When we found not much appearing (beyond alien thistles and dandelions), we began to plant a mix of seeds designed for such a woodland[8]. In cooperation with a larger study[9], we began sampling the herbs in the grove every second year, beginning in 1985 and continuing thus far through 2017.


Some results are mixed in with the discussions above. It just seemed easier that way.

Other results are reported below. In some cases, the conclusions are based on scientific data. In other cases, the statements are just judgments from observations. Lest this approach concern some people, let us point out that if a plant species was not found on the site for many years, then appeared in good numbers where seeds of that plant had been broadcast, then spread to be common over a wide area, it seems reasonable to report that result without apologies for the lack of numbers. There is not time for random sampling of everything. And we can draw practical conclusions without it, in some cases. We will start with some general answers to the three basic research questions posed earlier and follow up with examples of data sets that along with observations and judgments informed those conclusions.

How well will a damaged ecosystem recover, and how much apparently missing biodiversity will just come back in response to remedial care?

Very few plant species that were not on our initial inventories came back from the seed bank or otherwise appeared. This was disappointing. On the other hand, many conservative species that had been present in small numbers increased dramatically. A few species (notably the endangered Bicknell’s geranium) did seem to emerge in response to the burns.

How much missing plant biodiversity can be re-assembled through restoration?

As best as we can determine, 345 native plant species seem to have survived on the site (some in very small numbers) when we started. Today, the list includes 487 native species. That overall increase in species diversity may or may not persist over time. Whether it will continues to be an ongoing part of the experiment. Many rare or conservative species seem to be increasing in numbers and extent. Random sampling in many areas shows gradual increases in plot diversity in the areas sampled.

What is the impact of this restoration work on the animals?

Five species of snakes and five of amphibians were found on the site when we began. All seem to be doing as well or better than they did then. In contrast, there are many unmanaged areas along the North Branch that once supported those species where, as the invasives increased, populations have been lost. Few conservative invertebrate species have been found; data on the somewhat conservative species has not been analyzed sufficiently to evaluate trends. Birds have made an impressive comeback; many savanna species of conservation concern have returned and reproduce annually.

The following four data sets are quick-ish examples of how we have monitored success and failure at Somme Prairie Grove.

Six circles data 1994 – 2017

In 1993, we drove six stakes into the ground to mark six previously unplanted plots that looked similar to us. In all six we scattered seeds, and then in three of the circles chosen by flipping a coin we raked the seeds into the turf. Within the six plots we recorded existing plants in quarter-meter quadrats and followed up to measure changes in 2003 and 2017. Summary data is shown below.

Our initial purpose was to check whether we needed to rake the seeds into the turf. That turned out to be a waste of time, in this case.

But we've continued to sample the plants in those plots. The results show that quality and diversity in the quadrats continue to increase. The overall number of species (and of native species) is not increasing, at least for now.  

Species quality
Quality plus diversity
Number of native species
Number of species

Species quality (also called conservatism)
Notice that the quality continues to increase in the data taken 37 years after the restoration began and 23 years after the experimental seeding. Indeed, the quality rose as much during the first nine years of this study as it did in the subsequent 14 years, suggesting sustained increases slowing only slightly. We expect that the quality will continue to rise with good management.

Quality plus diversity (also called Floristic Quality Index)
These numbers represent a formula based on both the quality of the species and the number of species.

Number of native species
In the second interval (2003 - 2017), the number of native species has hardly changed.

Number of species
Declined slightly. What is happening here is that, as the number of “quality” species is increasing, alien and native “weedy” species are dropping out because they compete less well in a high-quality community. We would not be surprised to see the total number of species in these plots slowly rise over the decades, as the quality of the vegetation continues to improve, but that is not happening so far.

For more detailed explanation and additional data, see Endnote[10].

Vestal Grove data

So far as we knew (or know), no one else had worked much on full plant biodiversity restoration for tallgrass oak woodlands when in 1983 we began restoring Vestal Grove. This bur and Hill’s oak patch with a dense understory of buckthorn on the south edge of the preserve is typical of unburned oak areas, probably all of which have suffered minor to almost total loss of the plant species (and, less studied, animals) of oak woodlands. At the Morton Arboretum and in the DuPage forest preserves, Gerould Wilhelm and Wayne Lampa had begun working together to study burning as restoration in good quality woodlands. They advised and influenced our work, but at that time they were burning only, rather than burning and broadcasting seed.

Actually, for our first two years of woodland burning we too only burned, but as little revived from the hoped-for seed bank, we began broadcasting seed in the fall of 1985. As it turned out, the herb sampling transect we began here in the fall of 1985[11] allowed us to track the progress of plant recovery and restoration in considerable detail. A fuller account of this study will be published separately, but the following graphs tell a number of important stories.

Degradation and Recovery

In the graph above, the red line shows the average floristic quality of the plots[12] in the bur oak woodland. Quality rose substantially for the first few years, but a severe overpopulation of white-tailed deer (documented at more than 160 per square mile by Forest Preserve staff) here and nearby prompted a deer culling program by both the Forest Preserve and Village of Northbrook staff. During 1990 to 1993, the years of greatest deer density, the floristic quality of the oak grove dropped substantially. Following the deer culling program, begun in 1993, quality rose again, until progress was reversed by a moratorium on all restoration activity, imposed by the Forest Preserve board president[13] (ending deer culling, prescribed burns, invasives control, and more). When burning and other restoration of the grove was resumed in 2003, quality began to rise again. 

The colored lines above graph the abundances (total cover) of four different types of plants from 1986 to 2015.

The red and yellow lines track rank weeds (red) and fairly weedy species (yellow).

The green line tracks the highest quality species (that is, the most conservative).

But the blue line is probably the one that deserves most attention in this brief account. It shows the amount of cover by plants of “relatively high-quality” (coefficient of conservatism of 4 to 6). These seem in this case to be the species most responsive to good care, or its lack. They increase to double their abundance in the first few years – then lose half their gains. Following deer culling, they rise again to four times their former abundance only to plunge again when restoration is paused. With the return to good management, these relatively high-quality species increase to about 800% of their original level. (That's as of 2015. The 2017 data is still being processes. Stand by!)

Note that the very high quality species (green) advance from nearly nothing to more robust than both weedy categories combined (which had initially been dominant).

Site-wide Vegetation Quality

Beginning only in the year 2000, we began random samples of the overall site every four years. We started this monitoring in part because the moratorium was still hampering us, and it seemed valuable to have hard scientific data to make the case for good conservation management. It would have been better to have started earlier, but there’s only so much time in a day. Actually, to some extent, we have a form of “before” data in that parts of the site are still hardly managed, and we can compare the managed to the unmanaged areas. (Potential bias is introduced to the "grassland" areas by the fact that we managed first the best prairie-like areas first, but they were a very small part of the site, and few or no random points landed in them during this sampling.) These graphs also help us compare how the woodland areas are doing compared to the grasslands (that is, prairie and savanna).

The above graphs represent 113 random ¼m2 samples taken in 1996 and 2000. Some simple messages illustrated by the graphs above are:
  • Restoration works, in that floristic quality and plot diversity is dramatically improved in the areas under restoration.
  • Grasslands and woodlands responded remarkably similarly.
  • We still have a long way to go, as a high-quality grassland has Floristic Quality scores in the high teens or low twenties, and our averages don’t even reach 10.

The above graphs represent about 55 random ¼m2 samples taken in each of every fourth year from 1996 and 2012. These results may look like a "nothing-burger" - but may in time be among our most compelling graphs - if we're right. Our "hypothesis" is that this ecosystem will heal and heal in terms of what we understand as quality - over time, given good stewardship. When we compare the trends over the first twelve years of this study (begun during the stewardship moratorium), we notice the following:

1. Lazy stewards have not yet analyzed the data from 2016, though that should be done soon, and this graph will be updated.
      2. Quality was still falling during the 2000 – 2004 interval. The explanation, we believe, is that the recovery from the moratorium took that long. Brush and noxious invasive weeds had spread dramatically, and it takes years to reverse degradation, especially when areas are in the “intensive care” phase of recovering from "major surgery" following the cutting of dense brush.
      3.  It may seem curious that the “unmanaged” areas also decreased in quality from 2000 to 2004. But the "unmanaged" (less managed?) areas had been benefiting from the control of invasives (because they would otherwise re-invade the recovering areas) and fire. Thus, before the moratorium, we had been providing some benefit to otherwise-unmanaged areas. 
      4. We are eager to see what that 2016 data shows. (We do our data analysis during the winters. But, hey, we need also to cut a lot of brush in winter, especially in wetlands, when the ground is frozen, so please give us a break. We’ll get to it.)

Challenges and Priorities Ahead

Drafts on this component are circulating. They’ll be added here when a draft is ready.

Summary and Conclusion

Expert judgment and data on many groups of species suggest that the restoration of Somme Prairie Grove has achieved substantial gains and is heading in the right direction. Overall site-wide gains suggest that after four decades the site overall may be about half way toward our goal of recovered high-quality natural ecosystems.


It would be truly impossible to list everyone, but some of the major Somme Prairie Grove contributors who may not be listed in the text include:
Jane and John Balaban, Karen Glennemeier, Eriko Kojima, Linda Masters, Lisa Culp Musgrave, Sai Ramakrishna, Jerry Sullivan, Gerould Wilhelm, Greg Mueller, Ben Risk, Marlin Bowles, Steve Apfelbaum, Alan Haney, Steve Byers, John Johnson, Robbie Sliwinski, Paul Swanson, Nora Gavin-Smyth, Steve Thomas, Chris Benda, Randy Nyboer, Deborah Antlitz, and Monica Mueller.

Restoration and study of all the Somme preserves in recent years have benefitted massively from the dedication of Eriko Kojima who initiates projects, coordinates new volunteers, plugs leaks, and finds ways to help make other people’s time more valuable.

Many thanks to Kathy Garness for patient proofing and good questions.  


[1] Our evolving awareness of the savanna is summarized in “Just a few oddball species: restoration and the rediscovery of the tallgrass savanna” in Restoration and Management Notes 6(1): 1988. A more technical treatment of our perception of the savanna at that time can be found in "Rediscovering the Tallgrass Savannas of Illinois," Proceedings of the Tenth North American Prairie Conference, Denton, Texas, 1986.

[2] Some people have charged us with not doing real science because we did not have control sites to compare our efforts with. While there’s some value to this concern, we have argued that we have actually been doing a larger and more challenging experiment than the ones our critics preferred. To start with, our experiment has lasted four decades, which few comparable experiments do. And our focus was a plot of more than 80 acres (more than 30 hectares). To paraphrase Stuart Pimm, most ecology fails to elucidate many ecological phenomena because it studies a few species in a few acres for a few years, but most ecological process require more, bigger, and longer to truly function.

Of course, we do many little controlled experiments, and we publish some of them. But the main thing we’re trying to do at Somme is to restore diverse quality to a savanna. With the resources available, we couldn’t possibly do that on many large sites. So we’re learning what we can as best we can. If we’re successful, and the patient survives and revives, it may be one of the few of this level of diversity that will be available over the years for black-soil savanna study.

Part of the problem with some critics is that our story has been sensationalized in the press as one of those American “rugged individual” or “lone rebel” stories. Those dramatizations are off base. We relied on broad expertise, from the beginning. One added special advantage accrued to the Somme preserves when Stephen Packard became Nature Conservancy director of science and stewardship – and focused on savanna conservation here. Many visiting experts provided advice when they looked at Somme or when he visited their comparable sites or through other exchanges. Special thanks go to Kim Alan Chapman, Doug Ladd, Jack White, Kat Anderson, Rich Henderson, Jerry Wilhelm, Paul Nelson, Bill Jordan, and many others.  

[3] Somme Prairie Grove contained remnant prairie, savanna, and wetland. Though the good quality remnants comprised only a few of the 85 acres, the fact that the rare plants survived likely meant that many remnant populations of animals (especially invertebrates), soil biota, and other species and processes likely survived as well. Thus, this experiment was one of restoring what was partly still there, rather than starting from nothing but a corn field.

“Prairie flora” that survived included prairie dropseed grass, hoary puccoon, smooth and downy phlox, porcupine grass, short green milkweed, New Jersey tea, prairie violet, yellow stargrass, and many more. Note that all these species, that we originally perceived as evidence of prairie, would also be present in savanna. Species present that are more typical of savanna included wild columbine, wild hyacinth, woodland puccoon, purple vetch, Maryland snakeroot, small sundrops, and others. Quality wetland species included American slough-grass, Wolf’s spike rush, the sedges Carex atherodes, buxbaumii, crus-corvi, vesicaria, Sullivant’s milkweed, and others.

[4] Betz provided ongoing mentoring. Schulenberg sent written guidance based on his work in the Morton Arboretum. Harold W. Rock had in 1971 published the Prairie Propagation Handbook. Boerner Botanical Gardens, Milwaukee, Wisconsin. In introductory comments he had mentioned that the restoration pioneers at the UW Madison Arboretum had found that the seeds of some prairie species would grow successfully if merely broadcast in an old field turf. These comments suggested that we might test the contrary views of our mentors, which let to “inter-seeding” as our major propagation method.

[5] Packard, S. and Cornelia Mutel eds., 1997, Tallgrass Restoration Handbook: for Prairies, Savannas and Woodlands, Island Press. Techiniques used at Somme are most specifically reflected Chapters 4, 5, 11 and Tables 5.1, 11.1 and 11.2.

[6] Packard, S. 1994. “Successional Restoration: Thinking like a prairie,” Restoration & Management Notes, Volume 12, Number 1.

[7] Packard, Stephen and Linda Masters, 2008, “Restoring Conservative Prairie Plants to an Old Field Turf,” Restoration & Management Notes, Volume 26, Number 2. (This journal today is called Ecological Restoration.)

[8] “Restoring the Herb Layer in a Degraded Bur Oak ‘Closed’ Savanna,” Stephen Packard and John Balaban in Proceedings of the North American Conference of Savannas and Barrens, James S. Fralish, Roger C. Anderson, John E. Ebinger, Robert Szafoni, eds. Illinois State University, Normal, IL 1994.

[9] The study was proposed and supervised by the Illinois Nature Preserves Commission and funded by the Illinois Department of Natural Resources. The study was designed by Gerould Wilhelm, Marlin Bowles, Steven Apfelbaum, and Alan Haney. Along four transects that spanned the width of the site from east to west, the study recorded trees, shrubs, herbs, lichens, small mammals, birds, and some invertebrate animals.

[10] This area where this experiment was conducted was typical of the “old field” areas of this site. Although no seed had been planted here, it had been burned many times and such invasives as white sweet clover weeded many times in its 14 years of previous stewardship. Thus the 1994 data may be typical of a burned, weeded, unseeded old field here.

To re-find the plots we installed metal stakes at their centers and marked their edges by temporarily inserting flags in circles with radii equal to our four-pronged rakes, resulting in plots of 6.15 m2 (or 66 square feet). We recorded the positions of the stakes (and easily re-found them decades later) by triangulating to recognizable trees in the grove to the east. (The plots ranged from 17 meters to 32 meters west of those trees.)

In the chart below, the numbers represent the sampling inside the planted circles. We identified species within six 1/4 m2 plots (placed regularly inside the circumference of each circle).

Mean C
Native Mean C
Native FQI
Native Species #
Species #

See Swink and Wilhelm (1994). For a technical on-line explanation of terms see: [[[]]]

The six species with highest Relative Importance Value(RIV) – a measure combining frequency and how much ground the species covered – in 1994 were rigid goldenrod, early goldenrod, field hawkweed, a sedge (Carex hirsutella), meadow fescue, and Canada bluegrass. These species suggest a relatively common old pasture in a former prairie or (especially given this sedge) savanna.

In 2003, only one of the original six highest RIV species held their leads. Then the big six were big bluestem, prairie dropseed*, gray dogwood, early goldenrod, rattlesnake master*, and wild quinine*. The species with asterisks had been in the planting mix nine years earlier. Big bluestem was not in the seeding mix. But in the early 80s after our first burns, one remnant monster plant of it stood above everything else in that part of the preserve. Under the burn regime, it was spreading on its own (too much, in our view).

In 2017, the six species with the highest RIV were big bluestem, prairie dropseed, wild quinine, gray dogwood, Carolina rose, and nodding wild onion. Thus, we have four of the 2003 species and two new ones. Change seems slower.

Two tidbits of observations about the Six Circles results:

1. White prairie clover

A small amount of the seed of this highly-conservative species was in the planting mix but not recorded nine years later. (The slightly less conservative purple prairie clover was plentiful after nine years.) However white prairie clover was found in the center of one of the plots in 2017. Did it really take more than nine years to be noticed? Had the seed lain in the ground for some years before it germinated? Had the deer eaten down this very palatable species repeatedly, so that we only managed to record it by chance on a year when the deer had missed it?

2. Woody invasion

Although these six plots represent an interesting planting experiment, they don’t well represent the surrounding area. We do little restoration in the part of the preserve where these circles are, which has been largely on its own for decades. But notes remind us that in 2004, after we had triangulated and found the circles again, we cut out and herbicided buckthorns, bur oaks, Hill’s oaks, and shagbark hickories “in and adjacent to” the plots – so that the trees wouldn’t interfere with the herb planting experiment. Arguments could be made either way on what approach would most have benefitted the experiment, but we chose removal of the trees. The note doesn’t mention gray dogwood. Perhaps there was little. Perhaps we forgot to list it. Or perhaps we decided that that species, present originally, was indeed part of the experiment. Its “total cover” 107 in 1994 which increased to 316 in 2003.

In any case, to our surprise (shock?), when we came to sample the plots in 2017, it was apparent that woody plants were dramatically increasing. (See photo, below.) Dogwood was much denser in all directions. Inside the plots its cover was 185, but in our sample immediately outside the plots it was a whopping 519. Bur oaks, scarlet oaks, and shagbark hickories were frequent, in the plots and to the east and south. Young trees in the grassy areas typically have their tops burned back every few years, but in this area (perhaps because of shade from the east and south), they seem to have been sprouting back bigger and bigger. As this is a savanna restoration, the return of these trees to this formerly cleared field would be considered by many (including us) a plus. But the dense dogwood may represent a management challenge. If it increases just a bit more than it has (given modest fuel because the shaded grasses aren’t supplemented by plentiful oak leaves), the dogwood may start to shade out the herbs and grasses and further reduce burnablity by all but the more intense fires. This is a challenge worth thinking about.

Dogwood brush and young oaks seem to be increasingly dense in the Six Circles study area. Nearby, however, are similar areas with dense, good-to-high-quality grassland vegetation with few shrubs. The area of this mosaic of brushy/non-brushy patches has burned on the average of once every two years during the last three decades. 

[11] A permanent transect marked by metal stakes was installed here as part of a study initiated by the Illinois Nature Preserves Commission in 1986. One of the four east-west transects (selected at random by principal investigators Steven Apfelbaum and Alan Haney) happened to fall just a meter north of the transect we had sampled in the fall of ’85. This fortune of randomness allowed us to continue the INPC experiment with the benefit of the ’85 data. Since, typically, a spring sample misses some fall species and a fall sample misses some spring species, we decided to sample the transect twice each year (in June and September) and combine the results so that the sample would include as much of the flora as practical.

[12] In the Illinois Nature Preserves Commission study, plants were identified and how much ground they covered was estimated in circular plots of one square meter each. These permanent plots were ten meters apart on an east-west transect. The data given here reflects the “weighted floristic quality index” (see

[13] See “And then … the Moratorium” sub-head in

PS: Other studies underway

There are so many other studies underway that it would weigh down this paper just to list them in detail. Perhaps that should be a future paper. 

Subjects include amphibians, dragonflies, butterflies, fungi, lichens, varied seed mixes and planting times, spread of species by roots, spread of species by seed, “Land Audit” plots, “Woods Audit” plots, macro-plot comparisons, seeding-plot monitoring of various kinds and purposes, and many individual rare plant species. 

In 2017 two new sampling regimes were initiated by the Illinois Natural History Survey (quality woodland baseline study) and Forest Preserve District staff (quality savanna baseline study). 

Need for additional studies
The studies done so far are a pitiful scratching of the surface of what should be. We have little direct study of soil organisms, most animals, and even the plants of most parts of the preserve. We also need more thinking about the kinds of monitoring and studies most worthy of doing. 

Need for additional stewardship 

As much as we love the data and the science, the stewardship seems more important. People can study later what has survived, healed, and been restored. Priorities today include seed harvest and broadcast, raising and transplanting plugs of key species that don’t do well by seed, control of reed canary grass, teasel, crown vetch (especially nearby “feeder” populations), oak rescue, shrub thicket experimental maintenance, brush clearing,