What Can This Rare Plant Teach Us About Ecosystem Assembly?

Report on a Threatened Species:   

Forked Aster (Aster furcatus or Eurybia furcata) at Somme Woods 

Summary

What we have learned from monitoring three transects 

Forked Asters established readily on land newly freed from excess shade. 

The patches gradually increased in size, but six years later, fewer new plants are establishing from seed.

In this woods under restoration, these rare asters were initially not fussy about habitat; they established well in mesic, wet-mesic, and wet woodlands (and, perhaps, savannas). 

And what we subsequently wonder

In the long run, will this rare species be a long-term part of Somme Woods? 

If so, in what niches will it end up?

Or will Forked Aster drop out in the mid or long term? 

Initially, will this rare species serve as a useful “cover crop” and niche creator that will facilitate the recovery of ecosystem health and biodiversity recovery overall?

Or, alternatively, might it become an aggressive pest?

Also – from a variety of perspectives suggested by these results – are we restoring the past? or creating a novel ecosystem? or what?

Here forked aster (white) grows with such quality species as elm-leaved goldenrod, sweet black-eyed Susan, and purple Joe Pye weed. But intermixed with these, the weedy tall goldenrod (leafy but not in bloom here) reminds us that this ecosystem is new, its future uncertain. 

Background

Forked Aster (with the scientific name Aster furcatus in most books – but Eurybia furcata in newer ones) is a Threatened species in Illinois and is globally rare.

Somme Woods, like most midwestern woodlands, was badly degraded for decades by grazing, fire suppression, and a long list of other injuries. As with any better-quality unmanaged ecosystem in the modern world, its best parts were likely losing biodiversity at the rate of 2 to 3% a year. Restoration has begun to change that, dramatically. Somme Woods is 255 acres in Northbrook, Illinois. We conservationists are in the early stages of understanding the composition and function of oak woodlands. 

Over the last few years, Forked Aster has seemed to increase dramatically in many parts of this Cook County forest preserve. 2019 seemed a good time to refresh and analyze our monitoring. This species offers us the possibility of studying how such a plant responds to regular fire, increased sunlight, competition, and the overall conditions of an oak woodland under restoration. 

A Plant of Mystery and Confusion

Though rare, this species is not restricted to one narrow niche.  Experts do not agree about its habitat; every source has it different. 

The NatureServe website provides the following comments on Forked Aster:
Number of Occurrences Comments: Several in Iowa (2, 1 county), Illinois (20), Indiana (14, 4 counties), Wisconsin (25), and Missouri (37, 6 counties, however, 30 of 37 EO's occur in a single county).

Population Size Comments: Many large populations are known, but stands are usually clonal, with relatively few genotypes present. (See Endnote A: Genetic Limitations.)
Overall Threat Impact Comments: Threats include … the absence of disturbance processes necessary for establishment; and over-shading by canopy closure which reduces flowering and clonal expansion.
Habitat Comments: Occurs in woods and woods edges to railroad rights of ways; moist, north-facing rocky ledges and stream bluffs, and open oak woods.

(Note: species that today are found mostly on artificial “edges” and railroad rights-of-way may be refugees from a vanished habitat.)

Gray’s Manual of Botany (Fernald, 1950) lists Forked Aster habitat as “dry woods and shaded bluffs.” In contrast, Wilhelm and Rericha (2017) offer, “This is a rare species of rich mesic woodlands and wooded seeps.” Thus, habitats run the gamut from dry to seeping wet. 

Swink and Wilhelm (1994) give one “interesting assemblage” of associates that includes such dry woods plants as wood betony, white oak, and sand bracted sedge (which in turn is an associate of prickly pear cactus). Yet this same assemblage includes swamp goldenrod and skunk cabbage. Those two groups of plants do not grow side by side, and yet this one colony of Forked Asters spans their differences.

As we were deciding over the years where to sow the seed of this species, we wondered if perhaps it actually might once have had broad amplitude in the now-largely vanished open oak woods. Was this plant forced into marginal habitats as our woods darkened with invasive and so many species dropped out?

What we did

Starting in 1977, the goal of the North Branch Restoration Project has been to restore the structure, processes, and biodiversity of the natural ecosystem that thrived here for thousands of years. Forked Aster has been in our planting mixes since at least 1989. It was clearly a plant of the North Branch, as it was found growing spontaneously at McDonald Woods, a mile from Somme. But the plants there had trouble setting seed, as do many remnant populations of this clonal plant. So we got additional seed from a more robust population in the Barrington area (See Endnote 1).

We treated Forked Aster like the hundreds of other species for which we gather and broadcast seed annually, and as with many restored rare species, we didn’t see much of it for many years. Our 1989 records show that we put all Forked Aster seed into our wet-mesic savanna mix.  In 2012 we recorded only six cups of seed (including “fluff”) gathered for our mixes, but by then were dividing the seed into five parts and putting one part each in wet-mesic savanna, wet savanna, and wet woodland, and two parts in wet-mesic woodland. We did not put its seed in the mesic woods or the open woods mixes – but the evidence now suggests that we should have. (Indeed, our records show that we were doing so in the special Somme mixes by at least 2017.) It has been doing increasingly well, as reflected by our 2018 report which includes 3 gallons of Forked Aster seed in the North Branch mixes and additional 6 gallons in the special Somme mixes. 

Our overall restoration and monitoring efforts at Somme Woods have dramatically expanded, with a few years of boosted recruiting and training beginning in 2015. Volunteers now annually cut ten to twenty acres of brush and pole trees. We now gather seed of about 300 plant species (most of them rare today) and in larger quantities. Staff and volunteers burn half to two-thirds of the site every year. We all devote hundreds of hours to combating invasive herbs including reed canary grass, teasel, and purple loosestrife. For more about our approach see Endnote 2: What we do.

What We Counted

For years we did not monitor this Forked Aster, as this species seemed to appear in small numbers from one end of the preserve to the other. But in 2015 we decided that the new Somme Woods populations deserved study. Our first monitoring transect for Forked Aster covered 5 meters on each side of the Middle Loop trail (starting across from the picnic shelter) running north from the parking lot for 230 meters (thus including 2,300 square meters of ground). 

Forked Aster along this transect occupies a variety of habitats. The first clumps are in open savanna and then a transition to an open white oak woodland. The path next crosses a darker wet woods and ephemeral stream with bur oaks where we found no asters. Next comes a bur, white, and red oak southeast-facing slope where most of the asters occur. Then comes a relatively level open wet-mesic woodland meadow (or small savanna?) with no asters. But they we found them again toward the end of the transect, in mesic red oak woods. 

We counted numbers of plant patches or "clones" and numbers of flowering stems. We considered each patch as one clone. If two seeds happened to land very close to each other, the result could be two genetically different plants being considered one patch. Between 2015 and 2017, the numbers of both flowering stems and patches about doubled. 

Table 1. Middle Loop Transect for Forked Aster

	2015	2017	2019
Patches	15	41	46
Stems	124	294	499

But the change from 2017 to 2019 seemed to tell a different story. Now flowering stems increased by 60% while the number of patches increased by less than 10%. Considering the analysis by NatureServe, perhaps Forked Aster had established well on bare soil after shade removal, but as competition from planted species increased, fewer new plants established.  Existing patches continue to increase their numbers of stems asexually, but they may not reproduce readily by seed under the intense competition of a rich woods (See Endnote 3: “The Middle Loop Slowdown – a Result of Associates?”) 

Contrary to our expectation, Forked Aster on this transect is doing well in the mesic woods but poorly in a stretch of moist meadow or “wet-mesic savanna.” 

A woods shows its history. Decades ago, the old white and bur oaks lost their lower limbs when invasive pole trees shaded them out. Sun-loving shrubs, grasses, and wildflowers were lost at the same time. Under restoration, with pole trees thinned to restore the light, a rich ecosystem now supports Forked Aster and a long list of quality plants (see Endnote 3). 

A second transect (128 meters) is newer and better documented. The initial thinning and planting were done in 2015. By 2017, the slow-growing perennial plants were well-enough established to monitor. This year we compared this streamside (wet and wet-mesic) area to our results with the mostly mesic woodland population in Table 1.    

Table 2. South Brook Transect for Forked Aster

	2017	2019
Patches	49	61
Stems	109	263

In this younger population, the number of patches has increased by about 20% while the number of flowering stems has increased by about 150%. Here the plants were predominantly growing with wet-mesic associates like cardinal flower, boneset, brome sedge, and swamp goldenrod. 

The third transect is an impressive 475 meters long, about a third of a mile. It’s wilder and woolier, darker, less-restored than the others, following a brook that sometimes has no channel, as it braids itself and changes courses. This long transect produced many surprises, which may appear in a future post, but the trend again was dramatically upward.

Table 3. Middle Book Transect for Forked Aster

	2017	2019
Patches	9	54
Stems	14	230

Number of patches increased by 600%. Number of flowering stems by 1600%. And it's not just within these three narrow transects that the rare Forked Aster shows irrational exuberance. It’s widespread throughout many “restored” areas (though absent in many other similar areas). 

What We Learned

Without any special care, these rare flowers now bloom on at least many thousands of robust stems throughout much of Somme Woods. No other Endangered or Threatened species has established this widely and rapidly at the Somme preserves.

Despite our initial apparent belief that this species has narrow habitat requirements, it now thrives in and near oaks in sunny to shady areas that range from mesic to wet. It has very different associates in each. (We don’t have truly dry or even dry-mesic habitats at Somme Woods.) 

Yet, in large similar areas, it is absent, despite large amounts of seed blowing around the site. There is a suggestion in our data that this species establishes best on bare soil in the earliest stages of restoration. 

We have detailed planting maps by date as well as detailed seed mix lists by year. It would be possible for a person with energy for it to study many questions in some detail using these data. The current monitors, however, have our hands full with what we’re already doing. We’ve learned that this species for now is doing well enough at Somme without additional help. 

What We Wonder

Over time, will this species settle down to one habitat? Or will it end up as scattered small populations in many odd places that aren’t quite right for most standard plant associations? Will it survive among some associated species but not others? Or will it just die out as the woods grows back towards its original quality and rich competitiveness, making the Forked Aster bonanza a brief flash in the pan, a freak phenomenon?

 

Here a young plant of Forked Aster grows with young plants of such conservative and competitive species as bloodroot, blue-stemmed goldenrod, elm-leaved goldenrod, Short’s aster, purple Joe Pye, wild columbine, and a number of woodland grasses and sedges. Will the densely clump-forming rare aster kill off these other desirable species? Or will they kill it?

Are these expanding patches a threat to the larger ecosystem? Will this Threatened species unexpectedly become a thuggish pest – continuing to form larger and larger clones that exclude most other species and reduce biodiversity overall? Unlikely? But something to watch and learn from?

This large clone grows among diverse conservatives species (see Endnote 3). The aster seems bigger, denser, and more competitive at this point. As stewards, we wouldn't feel good about it smothering out all those other species. 

Pushing apart the stems of the patch above reveals shaded-out bare ground under the aster. Will the surrounding conservative species in time restore diversity here and co-exist with the aster? Or in time eliminate it? 

Or can you have too many of an endangered species for its own good? We have heard stern warnings that managers should not attempt to make a rare plant common. The Illinois Plant Translocation/Restoration Policy states that injunction this way: “new populations of native plants in the wild should not exceed the presettlement abundance of a species.” 

We did not try to make this plant so common, nor do we expect it to remain so. There seem to be few studies of this problem occurring and fewer compelling arguments for what harm this unlikely situation might cause. Yet, here we may be facing it (although there’s little information available on what the “presettlement abundance” in a woods of this kind would be). Should we weed out some portion of these plants or omit their seed from future planting mixes?

Conversely, some conservationists have argued that the way to re-establish sustainable rare plant populations is to restore sufficient genetic robustness that the species can adapt to new conditions. Forked Aster may need all its genetic robustness if it is to find a long-term niche here, as it faces increasing competition from other conservative species in the young restoration areas here. Somme Woods has been under restoration only about three decades, with most plantings much younger. 

Our initial advisors suggested we plant seeds of this species in woodland seep areas. Is it possible that our current conception of the habitats of this species is an artifact of the degraded state of our woodlands?  Possibly the species behaved differently when fire-maintained woodlands were more open and sunnier.

This paragraph added following the discovery of Army Lake Woods in 2020: We belatedly have a "one-data-point" confirmation of the above possibility. Yes, in the highest quality bit of oak woodland we know, forked aster is plentiful in mesic white-oak woods. One example is a poor basis for extrapolation, but we seem to have only one surviving very-high-quality oak woodland. This example should at least give us the intellectual freedom to consider the possibility that this plant may have been, and may in the future be, at home beyond the highly-limited habitats where it currently survives. 

We remind ourselves that our fundamental goal at Somme Woods is biodiversity conservation. We don’t know to what extent this woods is becoming a replica of its historic self and to what extent it is becoming something new. We can't possibly know. So how much should we care – if the result conserves plant and animal biodiversity?

Let’s be real about the future. Major climate change is a given. And added to that is that fact that fragmentation, hydrologic changes, rain acidity, predator and prey imbalance, and changed air composition all require major long-term change in ecosystem characteristics. Our hypothesis long has been that the rare North Branch species and ecosystem types have the best shot at survival if they can maintain substantial populations and full gene pools. Will Somme Woods under the current kind of restoration evolve toward a species composition largely similar to what was here five hundred years ago? In other words, will the diverse conservatives from the diverse seed sources re-establish something much like the original? Or will it (and most ecosystems in the region) become radically different? As stewards, we suspect that the answers to those questions are in considerable part out of our control.

Yet, we still need to wrestle with what is the best conservation management to facilitate the best result, considering that this woodland, with most of its (invasive) canopy cut away, is like a patient after a severe operation? The radically altered community is in the intensive care ward – highly vulnerable to infection by a wide variety of invasives and thugs. (In our experience, attempts to make these changes more slowly result in different problems and, in some cases, and much poorer result.) If invasives are on the decline and diversity on the rise, we have some confidence that "restorative succession" (is there a better name for this process?) may be heading in the right direction. It seems naïve to imagine that we can somehow control the individual abundances of the hundreds of species that we are restoring. Thus, we tend toward an uneasy confidence that most species will work out most balances on their own. 

Many people once defined restoration as “putting things back the way they were.” That definition now seems old to us, and not in the best sense. For us, restoration is a tool in support of biodiversity conservation. Yes, perhaps under the conditions of the future, the classic oak wood diversity will evolve a community here much like the original. But what if some species once here just don’t make it? What if others that weren’t here rise to fill their places? Indeed, we wouldn’t be surprised if in 50 or 100 years, stewards and managers spend some of their time mailing seeds north or east and waiting for FedEx to deliver seeds and eggs or tadpoles from south and west. 

Patches of both forked aster and woodland sunflower can expand and wipe out most other plants.
What will happen when these two thugs meet head-on?
Only time will tell ...
... if we are there with the right tools to measure the changes. 

Rich ecosystems have always changed. Plants and animals move around, if they can. Conservation doesn’t mean keeping things as they were but does mean setting conditions so that as much biodiversity as possible can adapt and continue this journey with us. 

As we consider Forked Aster and the 500 other Somme plant species for which we are stewards, we wonder: are we asking the best questions to improve our ability to contribute to biodiversity conservation? Are we using the right measures to get good answers? Are we focusing on the right time frames to realistically explore ecosystem processes? We're trying to develop them. 

The map below represents another attempt to explore the scale question. It shows how many aster stems were visible from a 1.3 mile trail - that is, speaking with wry science-iness, a transect of 2,092 meters. We hope to explore this and related questions of measures and scale in a future Forked Aster post on this blog. What types of data will turn out to be most meaningful over time?

Overall, the questions we wrestle range from the happy to the weighty. We’re not going to answer them definitively at the Somme Preserves alone. But we hope to contribute.  

Endnotes

Endnote A. Genetic Limitations

Phd candidate Nora Gavin-Smyth who studied Forked Asters at Somme and other northeastern Illinois sites, wrote a Masters thesis: “Genetic augmentation reduces mate limitation in two rare Asteraceae species.”

Its Abstract reads: “This study assesses the effectiveness of augmenting pollen from outside populations in two clonal, SI species that are known to experience genetic bottlenecks. Remnant populations of Eurybia furcata averaged 13% open seed set and augmentation crosses between populations increased seed set by an average of 96% and by over 500% in the most mate limited populations. Populations that, because of previous management practices, are composed of mixed genetic lineages, averaged 36% open seed set but between-population crosses did not increase the average seed set. In remnants, 34% of within-population crosses were compatible in contrast to 58% in mixed lineage populations, indicating that mate limitation is driving the differences in seed set. Remnant Cirsium hillii populations received between population crosses as a supplement to open pollination, increasing seed set by 50%. Offspring fitness measurements for crosses of both species indicated no significant differences among cross distances or population status, providing no evidence of inbreeding depression in the populations nor of heterosis in augmentation crosses. These results provide compelling support for genetic augmentation as a management tool for clonal SI rare species."

Endnote 1a. Seed Origin and a Donor Habitat

Rebecca Collings wisely suggested that this post add a note on the habitats our seeds came from.

I wrote to Jim Vanderpoel of Citizens from Conservation to ask if he could describe the source of our original seed, which they generously supplied, and which has been subsequently enriched by seed from McDonald Woods (See Endnote 1B) and from Nora Gavin-Smyth's work (see above). Jim wrote back:

"I know the exact habitat of the forked aster in Barrington.  It grows on an occasionally mowed, shaded roadside with a mixture of native and invasive plants--it's right at the stop sign of the low-traffic Biltmore subdivision cross road.  I consider the population precarious.  There are a few nearby specimens scattered along the perpendicular road almost to CFC's little Steyermark preserve.  This includes the natural garden of a neighboring homeowner.  I don't know if the neighbor is aware of the plant.   The subdivision includes many old open-grove type trees but also a lot of landscaping plants.   I'd guess the original habitat would have been open grove." 

In 1994, Floyd Swink had written that Forked Aster "is frequent in the hilly country in the Biltmore Subdivision north of Barrington." I wondered how much survived there.

Then I found out. This turns out to have been the very population that Jim described, above. A few years ago, for her thesis, Nora and Tom Vanderpoel "looked around that neighborhood quite a bit" but could not find other surviving populations. 

Nora visited many northeastern Illinois populations for her thesis (which did not include site ecological information). For this post, she generously summarized how the habitat appeared to her for five other sites. Seeds from those populations resulted in the plants used for her experiments. (She provided plants left over from those experiments to us at Somme, and we subsequently added seeds from them to the Somme populations, following our Seeds Plan, which challenges us to restore seed from as many original, local populations as possible. The five habitat descriptions below suggest the apparently temporary and precarious state of current populations:

- A bike trail in Kane County--the habitat is degraded woodland becoming overgrown with woody species, some invasive. These patches were along the river, but weren't very wet, growing in a very shallow ditch. The Aster furcatus grows best just off the bike path where it seems to get mown from time to time. There are 4 long and large patches that are separated by about 30 feet. This was the one remnant population that had very high seed set and high number of compatible crosses between the patches.

- A Kane County nature preserve -- a high quality woodland though not very open. A. furcatus here is made up of about a dozen patches that were transplanted by volunteers from a bike trail when it was expanded. The plants were transplanted pretty far apart in this large Nature Preserve, and interestingly the seed set here is low, and there are not as many compatible crosses. I interpret this as the patches that were transplanted were likely genetically related but also the compatible plants may have been planted too far apart for pollination by a compatible plant. The patches with the most stems were in small openings in the canopy or woods edges. None of these patches were very close to water but somewhat close to seeps.

- Along a Lake County bike trail-- not high-quality woodland, much darker than any other site. Growing in dense, large patches, in small but not particularly sunny openings, about 10m from a large wetland.

- In a Lake County forest preserve, in a high-quality wetland. A. furcatus is growing in sunny open patches, as well as some less sunny openings in a wet seep. Very large, extensive clonal patches, but low seed set and low compatibility between patches.

- In Barrington Hills--just a single large persisting patch in a neglected nature preserve, with very conservative associates like Cypripedium candidum. The patch of A. furcatus was on the edge of a wood, not in a wet area, but 10m from road ditch.

Endnote 1b. McDonald Woods, a Donor Habitat 

Jim Steffen of the Chicago Botanic Garden’s McDonald Woods writes:

The locations where E. furcata was remnant in McDonald Woods would be what I would refer to as Flatwoods habitats. Associates included Lysimachia ciliata, Solidago patula, Cinna, Cornus obliqua, Fraxinus nigra, and Quercus bicolor. These areas are on the edges of what would have been a rich upland woodland dominated by Quercus alba, Tilia americana, Acer saccharum, Dentaria laciniata, and Podophyllum. It could be that these remnant populations survived in more open areas where they were not under the growing shade of the maple saplings, but they are very wet habitats. Generally speaking, after we enriched the gene pool with seeds from other sites, the areas where E. furcata is doing well from seeding would also be what I would call wet-mesic to wet habitats. In general, it appears to me that the plant prefers wetter sites. Most of the plants more often than not are in association with Quercus bicolor, Fraxinus nigra (before ash borers hit), Chelone, Rudbeckia subtomentosa, Lobelia siphilitica, Carex bromoides, Cinna, and other similar wetter-growing species. Although I have not looked carefully at the difference between clones and individual plants, it appear that the plant is spreading from seed as the clones are far apart. There seems to be more of it over the years and in different locations, but still in the wetter parts of the woods.

Endnote 2: What we do

If you’d like to learn more about the Somme approach, you might want to consider previous blog posts, for example: 

The Somme Prairie Grove Experiment

Principles of Somme Woods Conservation

How to Restore the Spring Flora of Oak Woodlands

Why Restore Spring Flora

When and How to Plant Woodland Seed

Are Woodland Sunflowers Thugs?

Endnote 3: The Middle Loop Slowdown – a Result of Associates? 

Vastly more seed than ever before now blows around the Middle Loop Trail area, but fewer new plants establish themselves. That’s likely due to the diversity of conservative associated plant species, making an increasingly competitive woodland turf. Below are associates of some of the patches along this transect (in approximate order of descending cover in each case) within 0.25 meters of the patches at the given distance from the curb at the start of the trail. The “rich white oak wooded slope” (where most Forked Asters thrive for now) was bare ground under buckthorn and pole trees about eight years ago. All the associates there (except Solidago altissima, Bidens frondosa, and Aster sagittifolius) were planted in seed mixes with the Forked Asters at the start of the restoration. 

In savanna

Meter 13.3: Solidago rigida, Eupatorium purpureum, Monarda fistulosa, Rudbeckia triloba, Solidago ulmifolia, Coreopsis tripteris, Daucus carota

On savanna/woods edge

Meter 30.2: Solidago altissima 90%, Coreopsis tripteris, Solidago juncea, Zizia aurea

On rich white oak wooded slope

Meter 79.7: Heracleum maximum, Aster shortii, Aquilegia canadensis, Cinna arundinacea, Sanguinaria canadensis

On rich white oak wooded slope

Meter 96.6: Eupatorium purpureum, Chelone glabra, Camassia scilloides, Solidago altissima, Bidens frondosa, Solidago caesia, Cinna arundinacea, Carex blanda, Aster shortii

On rich white oak wooded slope

Meter 132: Solidago ulmifolia, Aster shortii, Solidago altissima, Aster sagittifolius drummondii, Zizia aurea, Eupatorium purpureum

On rich white oak wooded slope

Meter 142: Solidago ulmifolia, Solidago flexicaulis, Heracleum maximum, Cicuta maculata, Eupatorium purpureum, Solidago altissima, Taenidia integerrima, Agrimonia parviflora, Carex gracillima

In red oak woods

Meter 200.5: Helianthus strumosus 95%, Aster shortii, Lithospermum latifolium, Ranunculus septentrionalis, Solidago altissima, Heracleum maximum, Lactuca floridana, Potentilla simplex

References

Nora Gavin-Smyth. Genetic augmentation reduces mate limitation in two rare Asteraceae species. Masters thesis.

Falk, Donald A., Constance I. Millar and Margaret Olwell editors, Restoring Diversity: Strategies for Reintroduction of Endangered Plants. Island Press. 

Acknowledgements

Somme Woods Forest Preserve is in Northbrook, Illinois. It is owned and managed by the Forest Preserve District of Cook County with much of the most detailed restoration work executed by volunteers coordinated by Forest Preserve staff, Friends of the Somme Preserves, and the North Branch Restoration Project.

This monitoring was done by Eriko Kojima, Paul Swanson, Sai Ramakrishna, Matt Evans, and Stephen Packard.

We share our monitoring data for the endangered and threatened species at Somme Woods with Plants of Concern, a community science rare plant monitoring program based at the Chicago Botanic Garden. For more information visit Plants of Concern.org.

Thanks for Questions, Edits, and Comments to Karen Glennemeier, Mark Kluge, Eriko Kojima, Rebecca Collings, Debbie Antlitz, Will Overbeck, and Gretel Kiefer.

Comments

From Mark Kluge

As for the larger question, it is a fascinating one. Since we were not present to witness climax succession before our woodlands began to implode under the weight of human disturbance, there is very little we understand about the ecological distribution and habit of many conservative species.  Given the scale of the Somme Woods restoration, there are things to be learned - but it may take 20, 30, even 50 years to learn them.

From Debbie Antlitz

My hunch is that many of these species are doing well while competition is not yet fierce; it is natural and expected that diversity may diminish at some future point when the clear winners are sorted.... however my understanding is that this is *not* what has been witnessed at the Sommes to this date, so maybe there is a lesson there that early diversity encourages sustained diversity? Runner-reproducing clones have an advantage in moving patches of ideal habitat, such as a burning shrub front that is burned back on one end but grows on the lee-side of the fire, or a woodland where falling trees open new patches, or in wetland areas that are subject to seasonal or even 10-year cycle hydrological fluxes. Given the aster is a wind-blown seed, that ability to colonize, clonize, and adapt to rapidly changing conditions makes sense in a savanna shrubland dynamic patch landscape.   

From Karen Glennemeier

You're laying out a bunch of questions that naturally come from your data, but you're very clear that what we have now are more questions than answers, and, importantly, that this is ok.  What matters is to keep asking the questions and keep figuring out better ways to try to answer them. I like the way you put the forked aster story in the broader context of the "chaos" of new restorations - how do we know when things have sorted themselves out, will they ever do so, does it matter?

I also like the type of data you've got:  It's data and monitoring that most stewards could do, it's not a super narrow, controlled experiment, it's a study that works with the process of restoration itself -- you're spreading seeds according to management plans, not experimental design, and you're counting plants in a systematic way within those areas.  It's a looser study than the kind that gets published in journals, and in some ways this makes the conclusions messier.  But in some ways it makes them cleaner -- if you were to design a tight, narrow study that did a good job of answering your specific question but wasn't really representative of the way restoration is done, then how would one interpret the results, wouldn't this get messy and speculative?

I think a lot about striking the right balance between "publishable" and "useful" experiments.  I don't have it figured out, but I think you're on the right track.

From Eriko Kojima

 If you have this species in an area you manage (or have authorized access to seed from nearby), you can do this too, and share your results. To start, this fall, pick as much seed as you can (without taking more than half). Or, like us, raise seed from two or more natural populations in a natural garden. Then plant it after you have removed brush, burned, and sprayed for re-sprouts. Make sure it’s sunny enough (open woods or shaded savanna), and it doesn’t matter if it’s wet or dry - try it in all kinds of wetnesses. Plant the seed as part of a diverse seed mix. When it comes up and blooms, maybe in two years, do a vegetation inventory, and repeat the transect from time to time. Let’s get to know this plant better. 

From Will Overbeck

As for the study design – I think it is a fine example of what we all should be doing as stewards – monitoring population trends along transects. It takes about an hour for me to do a 100m transect with 10 – 1m sq plots. We should encourage our natural resource managers to either conduct their own data collection and share results with stewards or cooperate with site stewards to facilitate collection by volunteers, archive data, etc.

From Nora Gavin-Smyth
Of course, my thoughts are drawn to the question of genetically controlled self-incompatibility that determines A. furcatus ability to make viable seed. I think that this is going to be one of the biggest bottlenecks to seeing new A. furcatus patches … The result that you are seeing of large increase in vegetative growth but small increase in new patches doesn't surprise me too much, because of this constraint on seed production.

I keep thinking about the differences between the A. furcatus at Somme Prairie Grove and Somme Woods--they are behaving so differently in those preserves and my understanding is that the SW population was sourced from the SPG population. In SW, it seems as though many of the seeds in the inside loop have established-- there are many many small patches and this pattern is unusual in comparison with SPG and with any other population, remnant or restored. I would be really interested to know how many of the new patches are the result of new seeds in the population (not from the seed that we sowed), and how many genotypes are contributing to the new generation. Did the population in SPG look similar to SW when it was early on? Have patches dropped out as well as new patches popping up? Were fewer seeds introduced to begin with? The results of my research indicated that not only the quantity of patches but the distance between patches effect how much A. furcatus will set seed.

I hope we can find a student at CBG to look at genotyping these populations and getting some answers to these really interesting questions! Thanks for getting me to think about those Asters again...

From Andrea Kramer

Your post made me think of Nora Gavin-Smyth’s recent MS thesis research investigating the role genetics plays in limiting seed set in populations of this species across the region. Her region-wide experiment showed clearly that genetic augmentation will be necessary for many remnant populations to successfully produce viable seeds. This was not the case for restored populations that had multiple source populations. I am curious to know more about the genetics at play at Somme, whether/how that may be driving the patterns you are seeing in the woods, and how that compares to other sites in the region. A region-wide molecular genetics study that complements Nora’s research would provide insight into some of the dynamics at play while informing future sourcing decisions about the species. It’s a project I’m hoping we’ll be able to tackle here at the Chicago Botanic Garden – it would be a great project for another master’s student in our graduate program, if you know of any good candidates.

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