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Wednesday, June 29, 2016

Thirteen Ways of Looking at a Rare and Conservative Plant

Intro 1
How much difference do the high conservatives make:
To ecosystem function?
To biodiversity conservation?

We consider the frequency of conservative plants key in identifying a Grade A prairie (“very high quality”) – compared to Grade B (“high quality”) – and plain old Grade C (“good”).

Are these plants also important to ecosystem function and ecosystem services? We suspect that diverse conservatives have some importance, in part because of our experience with the early restorations – the ones that were mostly big bluestem grass. Those restorations turned out not to support populations of most prairie birds, prairie butterflies, and indeed most prairie plants. 

Intro 2
Many of the prairie remnants I have worked on over the years had prairie lilies when I first saw them and today have few or none (for example: Glenbrook North, Wolf Road, Bluff Spring Fen, Plank Road). I wonder how many conservative plant populations we are losing. Does anyone keep track?

Intro 3
The very best restorations aim at sustainable and reproducing populations of the conservatives. Classic high conservatives of mesic black-soil prairie[1] include:

Prairie Lily
Prairie Gentian
Prairie Dropseed
Prairie Brome
(notice a pattern in some of their common names?)
Leiberg’s Panic Grass
Cream False Indigo
Heart-leaved Alexanders 
Scarlet Painted-cup
Small Skullcap
Prairie Cinquefoil 
Prairie Violet

To restore well – we want to understand our most healthy remnants. This post studies and ponders 13 more or less random photos of prairie lilies in a fine original prairie (which perhaps should not be named here) to consider the issues these conservatives raise.

Consider the diversity in the above photo. It’s easy to grow an “artificial” prairie lily all alone in a pot. But it’s hard to grow a “real” one in a “restored” prairie. Unnatural associates (like the oversized aggressive native species that make up the bulk of the vegetation in many restorations) apparently aren't compatible with it.

The prairie lily seems to require companions “that play well with others.” These are highly competitive in their own ways – but thrive in situations of great diversity. Consider the species visible around the lily in this photo (can you identify them?):

I pick out: Prairie betony. Bastard toadflax. Dropseed. Quinine. Rough blazing star. Rattlesnake master. Little bluestem. Indian grass. Rigid goldenrod. Bergamot. Starry false Solomon’s seal. Bush clover. 

(For that matter, notice that there’s also a small bee busy pollinating the lily. In so fine a prairie, invertebrate animals are typically much more diverse than even the plants.)

The healthiest lilies have two or three flowers. We saw no such displays of exuberance until we started caging the lilies from both deer and voles, some years ago. Under today’s conditions, both animals tend to keep these lilies so depleted that they rarely produce even one flower.

Notice the richness of associated plants again:

Rosinweed. Heath aster. Gray goldenrod.  Quinine. Prairie dock. Spiderwort. Yellow coneflower. White blue-eyed grass. Rough blazing star. Alumroot. Kalm’s brome. Grasses: Dropseed. Little bluestem. Indian grass.

Can you identify these 14 species by their leaves? If not, can you see 14 different kinds of leaves? We need more wonderful people schooled in botany such that they can “read the botanical landscape” through its foliage.

Three other species deserve mention here. Black-eyed Susan is the opposite of conservative. You might find it in the most beat-up and degraded of ecosystems. But it also seems to be a common plant in fine prairies. Unlike “more purely weedy” plants such as ragweed and tall goldenrod, it finds a niche in quality. A different weed, visible here, daisy fleabane is not typical of fine prairie. That one suggests a problem here This prairie wasn’t burned often enough. Brush invaded. Fleabane helps start to heal the wound when that brush burns. If and when the prairie heals well through more frequent burns, the weedy fleabane will mostly disappear.

Also – note the green exclusion cage (top right). It protects a prairie lady-slipper. More on that gem later.

Here again, most of the grass is the fine-leaved dropseed. But those gross leaves of gray dogwood (bottom right) are a serious threat. Even after a recent fire, they’re on the move and in time would eliminate all the other vegetation here. Indeed there was little actual prairie visible when we stewards first saw this area. But with mostly just burning, the outstanding diversity came back.

It surprised us. Without herbicide or cutting – just burning – the dogwood was largely eliminated from areas where it had created big dark domes. Somehow, the quality vegetation underneath survived enough to choke back the dogwood for a “Grade A recovery.”

Button blazing star. Spiderwort. Rattlesnake master. Wild quinine. Bush clover.

Grass and bison
The dense grass around this lily raises the question of the impact of bison on prairie diversity. Many experts believe that the bison’s preference for grass would help promote the diversity of rare forbs (wildflowers). Bison mouths are said to be able to pick out most of the grass while leaving most of the flowers.
Associates in this photo include many of the same species as above plus downy phlox (in seed), wild strawberry and Dudley’s rush.

Here the camera pulls back a bit. Three lilies in bloom. (One is an orange dot way in back). This is what a real prairie looks like. Conservatives are common. Lilies every few feet. Most of the species previously mentioned. Also: Prairie cinquefoil. Prairie brome. And the little green cage at bottom left protects a clump of prairie lady-slipper. These orchids are more often found in high quality fens and wetter prairies, but they seem happy in this mesic area. Super quality seems to mean super diversity, often of unexpected plants.

Don’t let this happen!
Parts of the Grade A prairie today look like this. It hasn’t been burned often enough. Brush can replace and kill. Here the damage prevailed, and over a few square yards, the prairie is gone. Herbicide can kill too. In one nearby area, contractors cut the dogwood and herbicided so excessively that all the rare vegetation they’d been asked to save was killed. Conservation can become a tangled web. A strong burn program is crucial.

Burned off dogwood twigs are visible here. No high conservatives. Rhizomatous mountain mint has filled in, along with a persisting clump of smooth phlox. Bindweed vines sprawl. Prairie thickets where shrubs and vines come and go under the influence of fire are an important part of big prairies, but we don’t have room for much of that in this little Grade A area.

Dragon and dog
This lily rises out of a bed of false dragon’s head, wild madder, and spiderwort. This and the previous two photos are in the now fairly degraded wetter swale. The shrubby dogwood (big leaves at top and bottom) had killed off most everything here decades ago. Recovery has been slow.

A Word of Caution 
This less-than-one-acre very-high-quality prairie is part of a much larger preserve of Grade B, C, and (mostly) D prairie. A trail runs adjacent to the very-high-quality gem. You can see it from the trail. You don't have to step on it. If you visit a place like this, please stay on the trails. Can you see the silver lady-slipper cage (on the right, a third of the way up)? Many vulnerable rare plants (with and without cages) are harder to see. They’re easy to trample and wreck. The old “Rules for Management” of Illinois Nature Preserves require visitors to stay on trails unless they have permits authorizing some necessary purpose. Are these rules enforced? Does people even know them?

Caution and Hope
Most people wouldn’t trample the lily today – even if they made the mistake of stomping over much of this Grade A prairie. But when the blazing stars (skinny now-green stalks at left) are in bloom, and as tall as we are, most people would not be looking for lilies and lady-slippers as they tramp through. Should we ask people to stay on trails in our few tiny high quality prairies? I’d say yes. True, the bison trod them. I look forward to the day that we have fine prairies big enough for bison and kids and us to play in. …

Disaster! (or Nature?)
The lily in this cage was chopped into bits by voles. The pieces are visible lying in the very middle. Voles do this in part to check out the tops for seeds. They ate nearly all the lilies we tried to protect - until  we started circling the bottoms with collars of hardware cloth. Are there too few vole predators these days? Need more snakes and weasels? Or is this something a larger population can tolerate?

Thanks to the volunteer stewards and staff who care for this prairie. Thanks to cage-maker Dan Ratner and co-steward Eriko Kojima.

A last look – and a wish
Indeed, thanks to everyone who supports the restoration and preservation of nature. These rare plants and animals utterly need us. Bless us and them and all creation. And bless this challenging and happy mission[2].

End Notes

[1]  In conservation, the word “conservative” refers to a species that is characteristic of high-quality natural ecosystems. These species are depleted or eliminated by such degradations as excessive grazing, invasive species, hydrologic manipulation, and lack of fire. They are often absent in “restored” prairies.

Characteristic conservatives of mesic black-soil prairie (with “Coefficients of Conservatism” in parentheses) include:

Lilium philadelphicum            Prairie Lily (10)
Gentiana puberulenta            Prairie Gentian (10)
Sporobolus heterolepis          Prairie Dropseed (10)
Bromus kalmii                        Prairie Brome (10)
Panicum leibergii                   Leiberg’s Panic Grass (10)
Baptesia leucophaea             Cream False Indigo (10)
Zizia aptera                            Heart-leaved Alexanders (10)
Casteleja coccinia                  Scarlet Painted-cup (10)
Scutellaria parvula                 Small Skullcap (10)
Dalea candida                        White Prairie Clover (10)
Dalea purpurea                       Purple Prairie clover (9)
Oxalis violacea                       Violet Wood sorrel (9)
Potentilla arguta                      Prairie Cinquefoil (9)
Viola pedatifida                       Prairie Violet (9)

In sand prairies and savannas, the prairie lily is more common as are some other conservatives. Which is good, but that’s a different system, likely genetically different as well.

Swink, F. and G. Wilhelm. 1994. Plants of the Chicago Region, 4th ed.

Taft, J. B., Wilhelm, G. S., Ladd, D. M., & Masters, L. A. 1997. Floristic quality assessment for vegetation in Illinois, a method for assessing vegetation integrity.

[2] Some land may be protected explicitly for biodiversity conservation. Other land may be protected for complexes of benefits including recreation, ecosystem services (including erosion control, air and watershed quality, carbon sequestration, etc.), aesthetics, genetic resources, research potential, adjacent real estate value, tax benefits, and many other reasons. We probably can't prove much about the value of high conservatives to erosion control or air filtration. But for at least a few of our best quality remnant and restored ecosystems, shouldn’t biodiversity conservation be the top goal that overrides all the others in the end?

Restored areas can’t replace the original remnants. But larger areas and larger populations may be needed for sustainability, evolutionary processes and, especially some of the rare animals. At the combined remnant-and-restored Somme Prairie Grove, we are very happy to have seen a dozen or so prairie lilies blooming this year. Prior to this year, we’ve never seen more than one or two. Nature can return and heal. Thanks to many wonderful people, who will be needed forever. Happily for them.

Which gets us back to the question: “How much should we care about prairie lilies?” We conserve natural areas partly for ethical reasons and partly for the possible future importance of biota we don’t fully understand.

It has been estimated that when we save a quality natural area, we are conserving 100 animal species (mostly small to very small) for every 10 plant species. And those estimates don’t include the algae, fungi, protozoa, etc. etc. that depend on the plants and animals. When we do our best to save nature, we want to save the whole community.  If species start dropping out, we are failing – not only for them but also because they are likely indicators for so much more.

Those arguments apply to original remnants. What about restoration? Does it make a difference to a restored ecosystem if high conservatives are common? There are good arguments to support both “yes” and “no” answers.

No: A damaged remnant or restored prairie (or degraded former high quality prairie) that maintains 90% of the plant species of a very high quality site likely provides many of the values and ecosystem services that first quality communities provide. Restoring 100% of what’s in a Grade A remnant is a challenging goal, but if we get 90% there, that may provide 80 to 95% of what we hope for.

Yes: If we are restoring adjacent to a high quality site, and if we can get the plant diversity (including conservatives) of that site to expand to 10 or 100 times its remnant population size, we may well be making the difference between long term survival or extinction for many populations of animals, rare bacteria, etc. etc. Indeed, we may be making the difference for overall sustainability for the remnant. Science can study the details of this when science can get to it. But for now, we are likely conserving something irreplaceable.

The answer is less clear (and more interesting?) when it comes to restoring an area not adjacent to high quality. Is it possible that some of the rare fungi, nematodes, etc. of the ancient ecosystem are surviving in small numbers and will increase sustainably when the plant species diversity returns? Will the restored plants be doomed and fail to thrive because their symbotic biota are gone? Can we, as some restorations have tried to do, restore soil from intact areas being destroyed by “development” – and the missing biota return that way?

Good questions all. Worth discussion. Worth pilot projects and research.


  1. Steve, I photographed at least two prairie lily plants at Wolf Road Prairie last June. This in no way reflects adversely on your analysis - the population is obviously small and subject to all the pressures such as deer, voles, and inconsistent burns. You are right, we will be needed forever.

    1. Mark, many thanks for the good comment. I corrected the text to read "few or none." Glad to hear you found two prairie lilies at Wolf Road. That means the population has the potential to recover. Good stewardship makes the difference.

  2. Thank you for posting this. So much if focused on killing the bad guys; its good to see a thoughtful discussion and thoughts on how the most precious natural treasures are faring. After years of burning I finally saw some violet wood sorrel returning to Spring Lake Nature Preserve, along with Michigan lily, bastard toadflax. then the deer ate them. My last act was to establish a small deer explosure where they had been.

    1. Thanks for the good news on Spring Creek Nature Preserve. The struggle continues.

  3. The excitement over bison being released makes me think of how people must have felt when another ungulate, white-tailed deer, was reintroduced to Illinois in recent history. Unlike deer, I hope bison will be managed in a way that will create diversity instead of eliminating it. Even with good management I am sure there will be some winners and losers. I just hope irreversible harm is not done to remnant prairies.

    When people begin working on restoration I think they typically underestimate the difficulty of the task. Diversity is the product of an interconnectedness which has developed over a long period of time which can be very difficult to force upon a blank slate. Instead of immediately expecting to reproduce remnant quality, we should have the goal of returning processes, like fire, and building the interconnections between life. Once the interconnections have been re-established then the conservative species will be ready to take their place in the ecosystem.

  4. There are/were a few prairie lily at Old Plank in the last three years, but sparse. The questions arise are they gone, just not present for now, nibbled away to come back later, did we trample them trying to save them? They appeared and then don't. They were meagerly surrounded by some associates, but mostly not, until more can be prodded out with fire. Maybe they didn't like the company they were in and retreated. First seen after the first burn in decades or more, not seen after the second consecutive burn. Did we overwork the area clearing invading species? Did our efforts prompt them to emerge only to lay them vulnerable to attack? So many questions.

    1. From Stephen and your observations it appears that the plants undoing is the very act of trying to reproduce. Once it flowers the voles find an irresistible target. Other than the cages, I do not know what could be done to prevent this problem. Maybe an associate that deters voles like a member of the onion family could be established.

    2. Pat and James, interesting report and comment. If they came back once, after all these years, that's a great sign. My experience has been that these perennial lilies may survive for years as a leaf or two, slowly building up a bulb big enough to try to produce a flower and seeds (accompanied by the risks that James implies). Burning encourages them. Aggressive, weedy associates may prevent light from reaching that single leaf. Diverse associates may be better at allowing some light through. The Plank Road Prairies have inspiring recovery potential. Pat and the Orland crew, thanks for your work there.