Could it be a formerly
more widespread species of rich wet prairies and woodlands - that now survives
mostly in specialized, alternate, or degraded habitats?
This post explores how
we at Somme have thought about a challenging, uncommon but not Endangered or
Threatened species – fringed gentian (Gentianopsis
crinita).
We spent hardly any time on it in
the early decades of our work. We were somewhat prejudiced against it, as an “Oh
My!” plant, too beautiful and unusual. We didn’t want to be distracted from,
say, Leiberg’s panic grass, bastard toadflax, and hundreds of other species that
seemed more central to our mission. Yes, we threw some gentian seeds around in
1979 and 1981. But subsequently, we focused our minds and resources on what we considered
higher priorities: species on the Endangered lists and, our highest priority, figuring
out what it takes to restore diverse ecosystem quality. (See Endnote 1.)
But fringed gentian turned out to
be more interesting and, indeed, rarer than we thought. That’s especially so
for black soil prairie and open woodland populations of the tallgrass region. (See
Endnote 2.)
NatureServe map of fringed
gentian populations is shown below:
The U.S. Dept. of Ag. maps occurrences
of fringed gentian in the tallgrass region – by county:
Fringed gentian seems to survive
in just one county each in Virginia and Georgia, two counties in North
Carolina, but in ten to twenty counties per state in the tallgrass region. Yet
this map may be misleading:
In 1994, Swink and Wilhelm's "Plants of the Chicago Region" showed
similar counties but provided this comment on their “western sector” (the book's
Wisconsin and Illinois counties): “The map suggests this plant is common in our
western sector, but it is actually rare there.”
Then in 2017, Wilhelm and Rericha's "Flora of the Chicago Region" lists Gentianopsis crinita for only
five Illinois counties, pointing out that they could not confirm the earlier
records for two counties. And black soil populations? So far as I could
determine, the only black soil prairie or savanna in our region that retained
fringed gentian was the one (not surprisingly) said to be the finest black soil
prairie remaining in Illinois, forty magnificent acres on unincorporated land
between Wheeling and Buffalo Grove. Sadly, tragically, immorally, this site,
called the Chevy Chase Prairie after a nearby golf course, was intentionally
bulldozed in 1977.
Destroyed, but there was a
message: fringed gentian may have been a species of our tallgrass prairie.
Finding no seed elsewhere, we of the North Branch got six pathetic seed
capsules from the “only somewhat sandy” Gensburg-Markham prairie in 1979 (see http://vestalgrove.blogspot.com/2017/10/a-second-chance-for-fringed-gentian.html ). For years, all the genetic heritage
surviving at Somme descended from those six capsules. Later we were excited to
find that some Chevy Chase seed had been rescued from the bulldozers and a few
plants bloomed in most years on protected land in nearby Long Grove. We got a
little seed from there too – and broadcast it in the gentian habitat at Somme.
Still, the breadth of the gene pool represented by our plants seemed dismally narrow. As a rule, for most other species, we gathered seed in ways designed to maximize how much of the local gene pool would have the potential to contribute to the new populations. We did this by a) gathering seeds from as many as possible local sites (with similar soils), b) gathering seeds from those sites over multiple years, and c) gathering diverse components at those sites. For example, as much as we could, we sought to collect seed form the early-ripening plants, late-ripening plants, plants from drier and wetter areas, more-shady and less shady situations, etc. When we propagated seed in gardens, we sought to replace existing plants from time to time with plants from newly collected wild seed. We rejected seed from plants that "volunteered" in our production beds, as we were concerned that they could represent "cultivars" to some extent. Support for these approaches is suggested by later studies like that of Espeland et al. (2016) who wrote:
Still, the breadth of the gene pool represented by our plants seemed dismally narrow. As a rule, for most other species, we gathered seed in ways designed to maximize how much of the local gene pool would have the potential to contribute to the new populations. We did this by a) gathering seeds from as many as possible local sites (with similar soils), b) gathering seeds from those sites over multiple years, and c) gathering diverse components at those sites. For example, as much as we could, we sought to collect seed form the early-ripening plants, late-ripening plants, plants from drier and wetter areas, more-shady and less shady situations, etc. When we propagated seed in gardens, we sought to replace existing plants from time to time with plants from newly collected wild seed. We rejected seed from plants that "volunteered" in our production beds, as we were concerned that they could represent "cultivars" to some extent. Support for these approaches is suggested by later studies like that of Espeland et al. (2016) who wrote:
Seed collection from wild populations is a first step in propagation of restoration materials (Basey, Fant & Kramer 2015). By taking a relatively small sample from a relatively large population, seed collection can cause genetic drift … Genetic drift can lead to an overall reduction in genetic variation and a greater risk of future inbreeding through mating between genetically similar individuals…
Genetic diversity (Ne) and phenotypic diversity have also been shown to confer stability at the ecosystem level... Key biotic and abiotic interactions that drive community structure and ecosystem patterns and processes are deeply affected by intraspecific genetic variation in foundation plant species. For example, the amount of genetic diversity within populations can influence competitive interactions between species and ultimately alter plant community composition … Genetic diversity can also drive community structure … and can sometimes be more important than interspecific diversity within the plant community.
Thus, for, say, compass plant, wild
hyacinth, and dropseed grass, the Somme populations started with just a handful
of original plants in a small area or two – but now represent gene pools from a
dozen or more larger populations and a diversity of habitats at those sites. We
wished that could be true for all species. If we tried harder, could we find
more nearby gentian sources to draw on?
We had an additional concern when
we began to restore savannas and woodlands. Like many older sources, in 1913 Britton
and Brown characterized the habitat of fringed gentian as “moist woods and
meadows.” Might “the gentians of the woods” represent other possibly vanished
or vanishing genetic alleles?
As we started taking this species
more seriously, we searched the scientific literature for clues but found
relatively little help until the publication of a 193-page study in 1992 – a Ph.D.
dissertation by Heather Jane Robertson. We learned a great deal from her
impressive research along with her illustrations, below:
Robertson’s diagram above taught
us how to recognize seedlings and first-year rosettes.
On the other hand, our overall conservation
strategy was very different from the one suggested by Robertson. She treated
this gentian as a single species conservation problem and therefore drew
conclusions unlike ours. We were being coached to envision our species restored
as part of complex and long-evolved natural communities, managed as much as
possible by nature. (Even today, a lot of conservation takes that more limited,
single species approach.)
Robertson may have been
handicapped by working in a region where the surviving prairies and woodlands
were much further degraded than even ours. She considered this gentian a
species that “can
only survive through a short part of a successional change from bare ground to
forest.” She visited 26 populations –
“almost all known sites in New York state.” Of those, only one seemed to be a
surviving remnant of a natural grassland or woodland. All the others (except
“landslips” were being managed by mowing or grazing or had been mined. (see
Endnote 4). Thus, in her “SUMMARY OF CONSERVATION RECOMMENDATIONS,” she writes:
“Sites which are not kept open naturally, for example old fields or
pastures (in contrast to landslips and other naturally open habitats), need
continued, active, management to prevent encroachment by woody plants and
development of a closed shrub and tree cover … Mowing or grazing vegetation to
ensure that herbaceous plants predominate will allow G. crinita to survive.”
Robertson doubted the reports of fringed
gentian growing in woodlands. As she put it:
“G. crinita requires
unforested conditions. Plants were sometimes observed growing close to scrub edges
or at the borders of open woodland that had few shrubs in the understory. If
this is a general feature throughout G. crinita's range, it might
explain the occasional published references to "thickets" and woods
as habitats (e.g. Gleason 1952, Scoggan 1957). Alternatively there may be more
shade-tolerant ecotypes in some localities.”
Or, as an additional alternative, perhaps
there once were woodlands that had a great deal more sun than our “natural”
woodlands do today – occurring as part of the fire-adapted landscape that
included prairie, savanna, and open oak woodlands in all eastern states. As
Robertson acknowledges:
“Fragments of
prairie, or "oak openings," which now support G. crinita populations in Ohio (Easterley 1979)
and western New York (my study) could have been significant for the survival of
G. crinita in the forest period. Native Americans
may have played a part in keeping such fragments open, for instance by burning
them to encourage game (Seve ringhaus & Brown 1956).”
Still, when she
gets to recommendations for conserving this species, she mentions mowing and
grazing, but not fire.
At Somme, we have seen enormous
fluctuations in gentian numbers from year to year. (See Figure 1.) Dr. Betz
first described such fluctuations to us, in the more mature prairie at Markham.
In one year, there’d be a big stand of gentians in a certain small area. Betz
would check that area the following year and find none – but would find a big
stand of them 100 yards away, in a place where he had found none the previous
year. Perhaps, we thought, at Markham great numbers of seeds waited in the soil
for many years, somehow deciding which year would be right to germinate at that
spot (perhaps a north-facing slope, or south-facing, or with relatively more
sandy soil, or silty, or with competition recently lessened by brush removal,
or by the death of some short-lived plant). Later, the Robertson paper gave
evidence suggesting no long-term gentian seed bank. Thus, another riddle.
Figure 1. 34 years of fringed
gentian data at Somme Prairie Grove
Blow up this graph, and you can see that in some years there is actually a bit of red down low, showing that a few gentians bloomed. For example: in 2003, Somme had six blooming plants. In years that show nothing at all, perhaps there were none; perhaps there were some here and there, but we never found them tucked away in Somme’s 85 acres; or perhaps we were just too busy to look.
If you’re interested in patterns
and puzzles represented by the graph, you’ll find some of them discussed in
this long paragraph. We got our six capsules of this biennial plant in 1979 and
planted them in Miami Prairie. Two years later, we collected seed from the
plants that bloomed there, and broadcast some of those seeds at Somme. So, the
seven plants that bloomed in 1983 started the Somme population, which then had
to wait another two years for 149 to bloom in 1985. Then comes another low
year; a few plants emerged from 1983 seeds that perhaps had lain dormant for a
year. The spectacular 900 plants counted in 1987 show an every-two-years
exponential increase. But why were there so few between 1987 and 1996? Perhaps
the ’85 and ’87 numbers had been flukes attributable to especially good gentian
weather. Perhaps our average Somme conditions aren’t so good for this species? Or
was it the deer? We do know from monitoring many other species that an
over-population of white-tailed deer peaked in 1993. Those deer devastated many
species that, like this gentian, were especially sought by the deer. Deer
control programs by the Village and the Forest Preserve, beginning in 1994,
could help explain the upswing that, on the gentian’s biennial schedule,
resulted in the explosion in 1997. And the “Moratorium” on all management
including fire for a few years subsequently could help explain low numbers for the
next decade. A few years of increased gentian stewardship by Lisa Culp Musgrave may explain the surge starting in 2008 and the drop after 2012. The good numbers in 2017 may reflect the efforts of steward
Eriko Kojima, who was an eager new seed-picker in fall 2015. She resumed gentian
caging and seed collecting, and the increase in seed has allowed us to
broadcast in many additional areas. Then, with little gentian stewardship recently, in 2023 we counted 1,266 gentians blooming in Somme Prairie Grove.
Bi-modal Associations
One variable not illuminated by
our counts of plants is the apparent bi-modal nature of this species habitat at
Somme. We find it in two very different situations. It blooms in some of the highest
quality areas – and some of the lowest. It’s not surprising that a biennial species
might thrive in the low competition of areas newly freed from dense brush. Some
of these “recent restoration” areas produce large numbers of plants for a few
years and then dwindle to no plants, at least for decades. Perhaps "a seed bank will express itself" once a "healthy" conservative turf has established. Young restoration areas
often pass from the “much bare ground” state through a “teenager” period where
a few aggressive mid-conservative species demonstrate an “irrational
exuberance” so ferocious that only the strongest survive. We do not find
fringed gentian during this stage. But we do find it in later stages where
conservative diversity has begun to restrain the mid-conservatives.
Since deer and voles wipe out
some unprotected populations, we stewards collect seed from protected plants
and distribute it where needed. We now skip the areas of aggressive mid-conservatives,
as we’ve found it does not succeed there. But we broadcast seed in wet-mesic
areas that seem to have available niches either because the more-restrained
high conservatives are running the show or because brush or weeds have been
controlled, and there’s plenty of bare ground. When we have collected and
broadcast seed, we have mixed gentian seed from both habitats together. Perhaps
we should encourage the development of populations adapted to the more
sustainable high-quality areas by segregating the seed we gather in the high-quality
areas and re-broadcasting that seed just in those areas. Or maybe our
current seed mixing is the best way to give the Somme population(s) every opportunity to assemble the richest and best gene pool?
Finding More Diverse Seed
At first we feared that all
natural, fire-dependent, black-soil tallgrass prairie and woodland populations
of fringed gentian in our area (and all areas?) had been lost. So we started
with the best we could get from “somewhat sandy” Markham Prairie. Later we were
thrilled to get a few seeds from the very high quality, now-mostly-destroyed
Chevy Chase Prairie (see http://vestalgrove.blogspot.com/2017/10/a-second-chance-for-fringed-gentian.html ).
But that’s a thin gene pool.
Recently we’ve looked to expand it. It turns out that a lot of “beating the
bushes” among conservationists turned up a few more survivors of original black
soil prairie and woodland populations (See Endnotes 5 and 6). Thus, in fall
2017, we are able to expand the Somme gene pool with seed from three sites
including likely black soil prairie, savanna, and woodland origins.
We’ve been recording associated
species in our varied gentian populations. Will they provide clues over the
years that will help with “conservation management” (or “sustainability
building”)? And we are considering various experiments (see Endnote 7) and what
monitoring would most effectively help us learn from them.
Another milestone: We broadcast
seed in recovering wet open woodlands for the first time in fall 2015. Eriko
Kojima reports fringed gentians there, in nearby Somme Woods, in summer 2017. One
plant was in the sedgy apron of a woodland pond, two were in a sedgy meadow
among the swamp white oaks, and “like five maybe” were in a drier restored
savanna with bur and Hill’s oaks and an original population of the endangered
dog violet (Viola conspersa) for that
matter. The adventure continues.
Endnotes
Endnote 1. To give credit where credit is due, it was our great privilege as
volunteers to be coached to experiment with an important, new, largely
unexplored discipline which may well prove to have global importance –
ecosystem restoration. In our early years, our principal supervisors, advisors,
and mentors were the Forest Preserve District (FPD) staff (especially Chuck
Westcott and Paul Strand), Professor Robert F. Betz (Northeastern Illinois
University), and Ray Schulenberg (Morton Arboretum). Later, in response to our
dedication and effectiveness, we were “adopted” by the Illinois Nature
Preserves Commission (INPC) and The Nature Conservancy – and the breadth of our
mentoring expanded to a great many universities and then-cutting-edge
professionals in government and not-for-profit agencies. Still, we were the
people working on these questions, day-to-day on the ground, as a volunteer
community. We listened to advice, kept current on our authorizations from FPD
staff, made our decisions, and did our work.
Initially, our vision and goals
came mostly from Dr. Betz and George Fell (INPC). We wanted to rescue and
restore what had been almost lost. But soon (thanks to the influence of younger
conservationists) our fundamental goal became biodiversity conservation. We
wanted to save natural communities with all their species and ecotypes – or
alleles. Simply put, an allele is a variant of a gene. For example, as humans,
we all have the same chromosomes, but one person’s chromosomes have the allele
for, say, blue eyes while another has the allele for brown. In plants, varied
alleles determine cold hardiness, drought response, disease resistance, defense
against some insect or another, etc. An individual plant has only one or two
variants of a given allele. In contrast, a population of that plant may have a
great many variants.
As we worked, we had to translate
the evolving scientific consensus into on-the-ground action. In the process, we
became part of the development of new ways of thinking about the ecosystem.
Yes, we were saving species, but we understood that the best and really only
way to do so was as part of complex, long-evolved, and still-evolving natural
communities, managed as much as possible by nature.
In our early days, “prairie
restoration” seemed quite separate from “natural areas conservation.” But soon
– because we were the only existing force that the INPC could enlist to manage
many neglected preserves – we began to apply our invasives control and
prescribed burning expertise to some of the most important ecosystem preserves
in the Illinois (for example Shoe Factory Road Prairie, Nelson Lake Marsh, Thornton-Lansing
Road Nature Preserve, Bluff Spring Fen and many others). As we did so, we
naturally noticed that the little fragments of high quality were just pathetic
scraps of survival surrounded by large “buffer” areas. It was obvious that the
species of the “natural areas” would have much improved prospects if they could
double or quadruple their population sizes by re-invading the invasive deserts
that then surrounded them. Thus began our development of “First Aid” recovery
techniques for natural areas, based on what we’d been learning on the more
degraded “incipient prairies” along the North Branch. Our work on prairies soon
expanded to savannas, woodlands, and wetlands as it became obvious that they
too required restoration thinking and techniques.
Endnote 2. Not finding a conservative plant species in a prairie or woodland today
may indicate little about whether that species was there before ecosystem
degradation. Few black-soil sites today have prairie lilies, white-fringed
orchids, or white prairie clover. Yet in the very finest such conservative
species can be common.
The greater fringed gentian
(Gentianopsis crinita or, in older
books, Gentiana crinita) can be
abundant today in sand the tallgrass region’s higher quality sand prairies and sand
savannas. People report that the largest and highest quality black soil prairie
in Illinois was rich with orchids and fringed gentians when it was destroyed in
1977. Even in sand areas, the fringed gentian is rare enough to rate monitoring
by the Chicago Botanic Garden’s Plants of Concern program. But our rich soil
prairie and woodland populations – if they once existed – are vanishingly rare
today
A similar species, lesser
fringed gentian (Gentianopsis procera
or virgata) is more typical of
pannes and fens.
Endnote 3.
This endnote starts with some
genetics:
“Seed collection from wild populations is a first step in propagation of restoration materials (Basey, Fant & Kramer 2015). By taking a relatively small sample from a relatively large population, seed collection can cause genetic drift, that is, a change in the frequency of gene variants due to sampling, affecting population genetic and phenotypic variation and sometimes means. Genetic drift can lead to an overall reduction in genetic variation and a greater risk of future inbreeding through mating between genetically similar individuals.”
(Espeland, Erin K. et al. 2016).
A fundamental principle of
biodiversity conservation is that we seek to save – not just all the species –
but all the gene pool. If there once were fringed gentians in black soil
prairie and associated woodlands, they likely had genetic differences from the
sand populations. Sand prairies, fens, and other specialized habitats are
precious and wonderful. But the rich soil prairies and woodlands were by far
the largest (and thus most genetically developed?) ecosystems in the region.
They’re now the most diminished. Fragmentation may be more problematic for
them, compared to the sites and populations that were more fragmented on the
natural landscape. Those genes may just want to flow and have fun.
Endnote 4.
Robertson writes about the single
“prairie” habitat that she found in New York:
“Remnant prairie sites are also known as "oak openings" in New York State (Shanks 1966). The G. crinita locality was dominated by species typical of tall grass prairies of the mid - west (Shanks 1966), principally Sorghastrum nutans , Andropogon gerardii , and Schizachyrium scoparium . Other characteristic species included Asclepias tuberosa and Monarda fistulosa.”
Robertson found five gentian
populations in “non-anthropogenic” habitats that Robertson called “landslips” which
consisted of massive erosion areas on steep slopes:
“These were on unstable sloping ground, usually below earthy cliffs in glacial deposits, and were dissected with gullies. The sites had been colonized by the same species, both native and introduced, that were also present in most of the habitats resulting from human disturbance and management, i.e. the old fields and roadsides. For example Aster lateriflorus , Solidago canadensis , and Euthamia graminifolia were recorded at both kinds of site. Other less common species found on the landslips included Sheperdia canadensis and Lonicera dioica, and in wet areas Parnassia glauca and Equisetum variegatum.”
Endnote 5.
Our original six capsules from
Markham probably held about 300 seeds. We got fewer than that from the “black
soil” Chevy Chase seeds. When we started thinking more seriously about Gentianopsis crinita, we were reminded
of how thin the starting gene pool was. We reached out to people who might know
of other populations.
Jim Steffen of the Chicago
Botanic Garden alerted us to a small population near Lyons Woods – a black soil
area that was originally mostly savanna and oak woodland. We learned that Lake
County volunteer steward Joyce Proper in 1998 found some plants growing with
other uncommon natives in an original savanna region south of Fox Lake near
Grant High School (about 20 miles from Somme). She gathered seed of those gentians annually for six years
and broadcast them in nine areas of a Lake County Forest Preserve where she is
steward. It turns out that FP staff knew about that Lyons Woods population and
authorized her to expand her gene pool with some of those seeds as well as
others from a third nearby preserve with a more sandy soil. In 2017, Joyce sent
us 2.5 tablespoons of the seed that resulted from those three populations.
Not surprisingly, most or all of
the populations started from Chevy Chase seed invested in people’s backyard
restorations are no more. But in trying to track them down, we discovered that
Tom Vanderpoel of Citizens for Conservation secured seed from Chevy Chase, and
healthy populations thrive in two of the CFC prairies. CFC generously donated about
a tablespoon of CFC seed to Somme in 2017.
We also heard from Sarah Schultz,
amanuensis for the veteran steward Barbara Turner, currently well into her
eighties. Sarah wrote “Barbara and Timmie Clemetsen ... made several trips to the
(Chevy Chase) prairie, only able to take as many plants as they could carry
each time. Parking was not close and Barbara remembers having to walk
quite a distance, lugging bucketfuls of plants. Bulldozers were ripping
up the prairie as the ladies were rescuing plants. More than once they
were chased away by the police. Timmie mentioned the property owner started
to poison the plants to deter the rescuers. They both said it was a
stunningly beautiful prairie, such a shame that it was destroyed!”
Thus, thanks to Barbara Turner, Joyce Proper, and many
others, the Somme populations of fringed gentian now include at least some of
the gene pool that survived in black soil prairie and non-sandy oak (savanna or
woodland) ecosystems. Thank you, all. We hope to retrieve more.
Endnote 6.
Part of our problem with the
fringed gentian was that we were embarrassed by its history with us. It was a
bit of a skeleton in our closet because it violated three of our original principles: 1)
it had come from far beyond our 15-mile seed source limit; 2) it came from
somewhat sandy soil, and 3) it was illicit. When two new and important
volunteers presented us with those original six seed capsules from a dedicated
Illinois Nature Preserve, we did not (yet) have approval to gather them. That
last sentence was an attempt at a polite way to say that they were kind of
pilfered. It was our deeply held principle that we were to be ethical about all
this. Personally, I was especially embarrassed that the seed came from the
cherished remnant managed by our beloved mentor Professor Robert F. Betz. I was
also torn about how to respond to the wonderful people who had gathered the
seed, with best intentions. In the end, I called Dr. Betz and explained the
situation. He was not happy. With heartfelt sincerity, I assured him that we
wanted to recover from this and suggested that a) he approve it retroactively,
b) that we spread the word that, as always, this seed was gathered with
approval, and c) that we repay the seed to Markham (from our first harvest)
with interest. He agreed, and we
proceeded. On the other hand, we didn’t gather any more seed from Markham, so our
gentians represented a very narrow gene pool.
As for the problem of "beyond our 15-mile limit" - we later, as advised by our mentors, established exceptions to it. One such exception was for species that no longer survived within 15 miles - if they once were present within it. We'd seek seed in the closest places where they survived. The genes at Somme now represent three populations, one of which was originally within that 15 mile limit, and the other two were close.
Endnote 7
Possible experiments: Really? Do we stewards have to do our own
science?
Perhaps if I spent more time
studying the scientific literature, I’d find scientific research results that
would help me make on-the-ground decisions for ecosystem restoration and
conservation. But I fear that time might not be well spent.
So – we sometimes ask: what
experiments can we indeed do in a living ecosystem – that would help
conservation? (And, for that matter, what might we do as “pure science” –
because we just have a burning desire to know)
Below are six possible fringed gentian
experiments. Most will take many years and will not likely ever be covered
by a Ph.D. study or “official, funded science.” Do you, dear reader, have any
recommendations? Thoughts?
1. Is it true that there’s no
seed bank in nature? Leave some areas unseeded for many years, and see if
gentians show up after long absence?
Challenges: This experiment may not be practical. It’s
so easy to miss one or two plants in acres of dense vegetation. One plant with
one flower can produce 600 seeds. An “explosion of plants where there had been
none” could represent the progeny of such a single plant. Also gentian seeds
can easily be spread when mud containing seeds congeals for a while on the feet
of various birds and mammals.
Implication: If there’s no seed bank, then widely
broadcast seed in prior habitat to help maintain a sufficiently large
population to be viable. If there is none, refrain from seed broadcast to
preserve whatever may be special about the genotype and seed bank of a given
population.
2. What happens after the rise
and fall of large populations of dodder (Cuscuta),
dogwood (Cornus), sandbar willow (Salix), or the various diseases and
other disturbances that have their impacts on high quality vegetation? Cycling
among conservatives. Smooth white lettuce: similar questions. Are all
conservatives long-lived, or are there some that cycle among each other
(perhaps using up certain nutrients or attracting disease organisms when they’re
too abundant). How might such changes impact the fringed gentian?
Implication: If a conservation site and population is
too small to take advantage of such processes, knowledge of how they work could
allow managers to move gentian seed to make up for the lack.
3. Fringed gentian currently
grows at Somme in more than twenty widely scattered stations. Annually monitor
each for gentian numbers and associated plant species. See if any group of
species seems to correlate with increasing or decreasing numbers.
Implications: Unclear, but useful hypotheses might emerge
once we were to study the associates that emerged, and their order of
appearance as populations rose or fell.
4. Are the genetics different for
a gentian population assembled from many remnant populations compared to one
un-ammended remnant population? If so, what do the differences mean? This would
be a lot of work, but Nora Gavin-Smith is currently doing something like this
with Somme and other sites’ populations of forked aster (Aster furcatus) Perhaps, all we need to do as stewards is to stick
to our various and varied protocols and keep good records.
5. Might this species function at
times as a monocarpic perennial? Do lots
of fringed gentians germinate every year – and then die back above ground when
conditions aren’t right? We see a version of that with the short-lived prairie
orchid (Platanthera leucophaea). It may
emerge with a few leaves, or even flower buds, and then, if the weather is a
bit too dry, wither above ground, sending resources back to its roots, and trying
again the next year. (The orchid most often dies after first producing seed,
but apparently some plants can produce seed for years – thus it’s not strictly
monocarpic.) In the gentian’s case, the question is whether seedlings and roots
might be able to survive for years, in nature? Thus, even without a long-term
seed bank, the species might be able to wait for years for best conditions.
Note: Silvertown (1984)
has argued (and to some extent demonstrated) that many monocarpic perennials
have been misunderstood as biennials.
Challenges: Finding large numbers of first year
seedlings and following them for years in the wild is indeed a challenge.
Implication: Similar to those in experiment 1.
6. Broadcast seed in high quality
areas – using two approaches. For some areas, broadcast seed from where it’s
easiest to get the most (large populations in degraded areas). For other areas, broadcast the smaller amount
of seed that can be “borrowed” or “pilfered” from the smaller populations in
high quality areas.
Implication: Managers
could follow the approach that led to the best conservation result.
Overall Comment: These experiments may not be the highest
priority for conservationists. But thinking them through a bit seemed at least
a useful thought experiment. Perhaps it might be more important to do such
experiments with Leiberg’s panic grass or bastard toadflax or other species
which may be more important to the recovery of a sustainable (high quality) habitat
for biodiversity conservation generally. Or maybe some people would be inspired
to do this work on fringed gentian because it’s more fun and quicker. (Given
that gentian is short lived, a ten-year gentian experiment might be equivalent
to a hundred-year experiment on bastard toadflax.)
Endnote 8
It has long been known (e.g.
Britton 1924) that scattering fringed gentian seeds in appropriate habitat will
sometimes result, at least temporarily, in a new population. Unfortunately, we
also hear that many of those populations die out over the decades. In our
attempts to launch populations as self-sustainable as possible on the current
landscape, such as it is, we found our standard ecosystem management (invasives
control and prescribed fire) was not enough. We also needed to counter three
types of animals.
Careful monitoring revealed that
deer sometimes eat every plant. For an annual or biennial with no long-term
seed bank like fringed gentian, that is very dangerous. Our solution here was
to protect a few plants in each population with wire fencing (see, for example,
http://woodsandprairie.blogspot.com/2017/07/ted-talk-part-2-politics-and-science.html ). Since a single plant can produce tens of
thousands of seeds (and perhaps receive pollen from all nearby plants?), we
find that plant numbers often increase dramatically when some are protected
from deer. (Citizens for Conservation has successfully sprayed vulnerable
species with deer repellent.)
On the other hand, in some cases
we found that many or all caged plants were eaten by meadow voles or
white-footed mice. Voles (which can be reluctant to leave their grassy tunnels)
are often deterred by ten-inch tubes of “hardware cloth” (see http://vestalgrove.blogspot.com/2012/12/wild-and-crazy-foxglove.html ). White-footed mice, which are great
climbers, scramble over and through our cages, but tend to harvest much less
than the voles, so, at least so far, we’ve just absorbed their impact.
On the other hand, insect larvae
are even more insidious. In the case of Somme’s prairie gentians (Gentiana puberulenta), larvae
sometimes seem to eat every seed before any substantial number ripen. (What kind of insect? In one case where we checked, the culprits were larval sawflies. Another attempt to identify the larvae in the seed capsules led us to the moth genus, Endothenia. The two types of larvae we find in the seed heads differ in one having a pointed head and the other rather a blunt head.) But with
the fringed gentian, we find that if we harvest seed capsules as they ripen, we
can pull them apart, find the nasty larvae, and remove them before major
damage.
Can any biologist can offer
any info or guidance?
We wonder if we could increase seed production by treating some of the seed heads with an insecticide at some point later than pollination time but before major damage has been done. So far, we haven't gotten any further with that than asking the question. We would hesitate to kill insects that were part of the natural ecosystem. On the other hand, increasing the currently pathetically small population of prairie gentians would much increase the populations of these malignant (?) or natural (?) insects. With increased populations, the gentians could likely cope on their own.
References:
, & (2015) Producing native plant materials for restoration: 10 rules to
collect and maintain genetic diversity. Native Plants Journal, 16, 37–53.
Britton, N.L. and
Addison Brown, An Illustrated Flora of the United States etc., 1913
Britton,
E. G. (1924). The fringed gentian - Gentiana
crinita Froel.
Torreya, 24, 102-103.
Espeland, Erin K., Nancy C. Emery,
Kristin L. Mercer, Scott A. Woolbright, Karin M. Kettenring, Paul Gepts, and Julie R. Etterson. Evolution of plant materials for ecological restoration: insights from
the applied and basic literature. Journal of Applied Ecology. 2016
Robertson , Heather Jane. A LIFE HISTORY APPROACH TO THE STUDY OF PLANT
SPECIES RARITY: Gentianopsis crinita IN NEW YORK STATE. Cornell
University, 1992.
Silvertown, J. W. (1984). Death of the elusive biennial. Nature, 310, 271.
Swink, Floyd and Gerould Wilhelm, Plants of the Chicago
Region, Morton Arboretum, 1994
Wilhelm, Gerould and Laura Rericha, Flora of the Chicago
Region, Indiana Academy of Science, 2017
Acknowledgements
For help tracking down old
publications, thanks to Gina Cordovi and Stacey Stoldt of the Lenhardt Library
at the Chicago Botanic Garden.
For helpful editing and comments,
thanks to Kathy Garness, Mark Kluge, and Eriko Kojima.
You may be embarrassed about accepting a few seed capsules. What embarrasses me is obtaining seed for a site is all about who you know and what you have done for them. I don’t understand why transferring seed should not simply be about doing the best thing for conservation. I also do not think stewards should determine whether or not seed is shared. The stewards do not own the land. The public owns it.
ReplyDeleteI was really disappointed when the FPCC finally issued the “Seed Source Policy and Guidelines.” I was left thinking, we all waited so long for this. What we need is pre-approved and ready to implement seed collection projects based on habitat. For example, seed collection of any non-T&E listed species should be authorized for say Shoe Factory Road Nature Preserve to be used at the calcareous gravel areas being restored at Bluff Spring Fen. Another example is the Spring Lake Nature Preserve and wetlands at Spring Creek.
After a while people just give up on trying to transfer seed between sites and they put effort toward other things. The end result is the preserves lose.
It's true that the public owns the preserves, and we, the public, should be demanding and helping provide the best possible care.
DeleteBut the public does not want just anyone doing whatever they want with the ecosystem. Trained staff and stewards are rightly entrusted with those decisions. I agree that the Seed Source Policy and Guidelines was disappointing, but we need policy and guidelines. It would be good to have discussions about how to improve it.
What a great article. Have you compared summer rainfall patterns against fringed gentian bloom quantity? If I am remembering correctly, both summers in 2011 and 2012 were characterized by six-week and month-long droughts during mid-summer, which could explain the low bloom rate in 2011 among surviving second-year plants and the lack of blooms in 2012 (presumably due to both poor conditions for germination and/or seedling survival in 2011 and bad bloom-time conditions in 2012?).
ReplyDeleteI also have a few thoughts about your New York habitat comparison. 1) From what I understand traditional indigenous maize agriculture also includes a ten-year "rest" period during which former cropland is left fallow to "heal" and return to nature. Early Euro Americans mistakenly thought these lands were left "unused." These lands are the original old fields of Eastern North America and would originally have had tallgrasses and associated wildflowers, including gentianopsis, I'd bet. Out east I imagine these old fields would grow into timber whereas where we live they would more likely to revert to prairie or open woods, depending on conditions. I wonder how these pre-European ten-year cycles match up with Heather Robertson's assessments for New York. 2) I seem to recall seeing fringed gentian and other wet species in New York State growing in more mesic locations than I'd expect... which I attributed to generally wetter and cooler weather conditions during late summer than what we get in the Midwest. Perhaps these two factors play some role in Roberston's assessment? In a region where most all non-dry land returns to dense forest, maybe human influence has more of a hand in maintaining gentian habitat than in tallgrass lands? And I find it interesting to think about these ten-year "old field" cycles... would gentians pop up in years 2, 3, 4, etc.? Also, there would be a cyclic mosaic of different stages of fallowness as croplands were retired from one place to the next, and the gentianopsis could pop up first here and now there, moving across one old field to the next.
It would be interesting to try this as an experiment in some of the flood-prone "potholes" that exist in cropfields in our region, which formerly would have been black soil lowlands.
I really feel that too many of the natural disturbance cycles have been disrupted and suppressed (for near a century now) for us to be able to truly appreciate the larger dynamic cycles of the prairie anymore... Bovine, cervid, canid, castorid, galliform, etc. These larger disruptions just don't exist anymore, and the only way to approximate their influence would be to implement much bolder acts of manmade disturbance on areas of landscape than we are generally comfortable with. Perhaps this is some of the mystery underyling conservative biennials like G crinita. Maybe black soil farmland is a good place to enact such experiments.
Lastly, one other aspect of genetic diversity that comes to mind is seed coat thickness... if certain strains of fringed gentian have harder seed coats to crack that persist for multiple years ungerminated, as opposed to thinner coated seeds that germinate more eagerly. Seems like you'd want to have a lot of both!
MES, thanks for raising many interesting questions. I agree that the difficulties of reviving the crucial cycles of the landscape of bison, native Americans, wolf, passenger pigeon, etc. range from titanic (and, potentially Titanic) to impossible.
DeleteOn the other hand, we are finding that natural ecosystems can recover to a great degree under restoration management, as that discipline is developing. The restoration of fire was slow in coming and very suspect in its early years. Now, in many applications, it is tried and true. Perhaps, as you suggest, other kinds of "prescribed disturbance" would be good to experiment with.
Fortunately, we have a clear goal - sustainable (especially conservative) biodiversity. If a management experiment tends to improve that, then it can be worth more work.
I do not think of fringed gentian (Gentianopsis crinita) as a tall grass prairie species. If it was truly a tall grass prairie species then it would be frequent in the Grand Prairie Region of Illinois. It appears fringed gentian inhabits areas on the edges of the Grand Prairie but is mostly located in the Northeast Morainal Divison. This is not to say tall grasses are not a component of Fringed Gentian habitat. These grasses are a component of prairie fens.
ReplyDeleteMy experience with this species is it prefers lime rich habitats like those where Carex granularis (limestone meadow sedge) grows. This habitat is not nearly as fertile as the soils found in Grand Prairie and consequently competition is reduced and fires are less intense. I have seen Fringed Gentian growing on a ridge of calcareous gravel elevated enough above a nearby fen that the habitat would appear to be dry-mesic. It may not only be the moisture Fringed Gentian requires, but more importantly the cooling effects of ground water flow. This cooling effect may allow Fringed Gentian to grow even if the ground water is several feet below the surface. In regards to the Somme Preserves, being near Lake Michigan undoubtedly helps this species.
I used to live in upstate New York. It is not surprising that New York has a lot of fringed gentian sites. It is a big state and limestone just about cuts the whole thing in half. There are also deposits of marble in the north and along the Hudson estuary that would be expected to provide habitat for fringed gentian.
Near where I lived in New York I found fringed gentian growing along the road in a ditch and further up the bank were water was seeping out of the ground. The road was highway 5 between Scotia and Amsterdam. I have tried to locate the place on google earth. This was over a decade ago and I might not have the exact spot right, but it gives you an idea of the habitat Fringed Gentian will occupy. I think the water was seeping out of the thinly vegetated area where rocks can be seen near the top of the bank.
https://www.google.com/maps/@42.9073844,-74.0989053,3a,75y,28.92h,90.3t/data=!3m6!1e1!3m4!1sqvrNfcycs5ueMBhWqmITzQ!2e0!7i13312!8i6656
This area is dairy country and consequently it is not surprising Ms. Robertson suggests mowing or grazing to prevent natural succession. I am sure the population I found was maintained by mowing. I am also sure there are more populations that have not yet been vouchered.
I agree that fire was historically an important component to maintaining fringed gentian habitat. In New York they have recognized the importance of fire for maintaining their pine barrens. However, they still do not seem to understand the importance of fire for maintaining their oak hickory forests, oak openings, or fens.
I have only seen fringed gentian in sandy soil, never in fine soil among the many IL & IN sites I have visted. I have seen it in woods/savanna; Ivanhoe in Gary, Conrad in Lake Village, IN (both TNC sites). Fringed gentian seems disturbance dependednt to me (like fame flower). There was a population of 2 dozen or so plants in Powderhorn (FPCC) along an ATV trail. After FoF contractors blocked access from 136th St, the disturbance disappeared and so did most of the fringed gentians (but as your data show numbers fluctuate greatly, but I have seen none in 2016-17).
ReplyDeleteTo make your abundance graph more meaningful you need to show how much (grams or ounces) seed was added within the site inventoried each year.
I have only seen a few individuals at IBP (2010-2016). My immpression is that fringed gentian are NOT thriving at IBP (which I consider a sandy site).
Thanks, JWPboss, for interesting observations and suggestion. Yes, it would be good to graph abundances as a function of amount of seed broadcast. Perhaps we can start doing that this year. (Previous years' records may be too general, as we may have only a site-wide measure of seed, and then we broadcast it in many different places around the site. It would be better if we recorded amounts site by site.)
DeleteYou remind me that there is another factor at Markham. Bob Betz and Carl Bartel planted a lot of seed at Markham, very possibly including the fringed gentians. Parts of Bartel are high quality; much of it is in an early or mid stage of restoration. The gentians there may be introduced and, in part, a reflection of the stage of recovery in the various areas.
Population graph reminds me of the 17 year cicada only more erratic. Peppoon and others list gentians as being beset by herbivory. Erratic eruptions help keep herbivore populations down and let some seeds and flowers hopefully get away... a strategy that might not be optimal where populations and land is small and herbivores supplemented by gardens.
ReplyDeleteOnce a related gentian was found horribly eaten, but then I followed a trail into he woods and found a clearing with 1) grass and trampling and lots of deer poo, and 2) the mother load of gentians I had never seen so abundant before.
Just because a deer eats it, doesn't mean it's gone. The baggy outer coat will spread seed and resist their crushing, as does their flatness. A deer swallows and then chews the cud, sloppily, as it lounges somewhere safe, usually a soft grassy clearing in a brushy area. Small seeds can fall from the mouth. If it dies the coyotes play a sport game scattering the rumen.
Like Oaks that work with fire, possibly some plants work with their consumers.
A good point: that some plants work with their consumers. But some don't. I have seen deer destroy populations of many species. Typically, the deer eat the gentians long before the seed is formed - a definite death sentence. On the other hand, I do wonder about the voles. They wait until seed is ripe ... and then destroy a lot ... but perhaps also are vectors of dispersal. Thanks for the comment.
DeleteHave you every tried to reduce the abundance of voles? I have not, but moving cottontails from Woodworth Prairie (where they are common) to Palos (where they are rare) helped forb flower abundance at Woodworth. Voles can reach extreme abundances. As a youth I was north of Dundee and west of West Fork and almost every step I took resulted in a vole sighting during one fall (I don't remember year, but in late 50s, I had never seen such lemming like abundance before nor since).
DeleteVoles are easily trapped and population reduction should not be difficult to achieve.
As you describe, in some years we find voles so abundant that they even dig up large areas of soil to eat plant roots. We have large numbers of such vole predators as coyotes, red-tailed hawks, great-horned owls - but no fox snakes or weasels.
DeleteOne control measure we have is our burns. When we burn the north half in fall, there are few voles in the north half over winter and early spring. Thus, when we have plugs to plant (of plant species that are hard to restore by seed), we plant them in the burned areas (so voles won't dig them up).
Experimenting with vole reduction in my yard, I have not found them easy to trap. Do you have info about or experience with good methods?
Oliver Pergams and I used Sherman Live traps at many natural areas in Cook & Lake Co. The traps were baited with rolled oats and peanut butter, set in evening and checked early morning. We were going for Peromycus -ear punch taken for DNA. We caught about equal numbers of Microtus (voles) as mice. My impression was that voles were easily caught in the Sherman traps. We released all the animals we caught.
DeleteConfirming your fire observations, an undergraduate did a project on effects of a spring fire on small mammals at Woodworth Prairie. There were few voles that spring and none were caught in burnt section a week after burn. Well into summer (late July or early August) there were no differences between the burnt and unburnt parts of the prairie in the number of voles caught per trap.
My recent experience suggests that some voles remain in the burned prairie, living underground on plant roots - digging up a lot of soil - at least for a while. Also noticed something I hadn't seen before. In the savanna, burned-over apparent vole nests often hold a cup-full or so of acorns.
DeleteWOW, I have not seen acorns in vole nests. I've read they hoard hog peanut also. I have not seen that either. There is so much to learn about nature -probably some individual native peoples knew much more about animals and plants than is recorded in words.
DeleteFor what it's worth, they seemed to be going after Hill's oak acorns - even though red oaks were closer. I saw quite a few of the acorn stashes - but I suppose it could all have been from one busy vole. I have not seen that before.
DeleteCommenting 6 years later, I'm very happy that I found this blog post! For several years now I've heard rumors from a local botany enthusiast that a SNP I manage in Winnebago County had Gentianopsis crinita, but I had no maps or other documentation showing its presence, other than a "it's on the edge of the sedge meadow." I've searched for years high and low, to no avail. Last week as I was taking advantage of the dry and cool weather to cut a fire break in the sedge meadow, I finally found it! Albeit a small pocket, it still persists in an area in desperate need of fire. The deer of course took immediate advantage of the easy access and have eaten several, but a few still remain. I'll be placing cages around the remaining plants tomorrow, but I would be interested in hearing any and all management/conservation tips for this species that you may have!
ReplyDeleteJoni, thanks for the good story. Glad they're still there. We now have so many at Somme that we provide little care. But when we felt they needed special help, we gave them deer cages and vole cages (both are in the photo of prairie lily in the post: https://woodsandprairie.blogspot.com/2021/07/28-photos-and-5-ideas.html).
DeleteI know that Citizens for Conservation has sometimes successfully protected rare plants by spraying them with animal deterrents sold in hardware stores.