Of Mice and Voles (and men and molds)

Voles are adorable and horrifying creatures. When I forget them, it’s tempting to think that the ecosystem is mostly about plants. But when chocolate-brown meadow voles are eating every rare gentian every year, I’m forced to remember that ecosystems are equally animal.

There’s a comparison with you and me. Our bodies are ecosystems that include more bacterial cells than human cells. As microbes are to us - voles, insects, etc. are to the prairie. Venerable ecologist E.O. Wilson called them “the little things that run the world.” (In case you like numbers, each of our human bodies supports one hundred trillion bacteria, molds and other micro biota, most of which help us more than they hurt.)

We who seek to save prairies, woodlands and wetlands once thought that our mission was simply to restore nature, and then nature would take care of itself. As we explored restoration, successes unfolded like magic. Hundreds of (until recently) rare plant species eventually found their niches and became abundant, and the ecosystem grew progressively more diverse and healthy.

Animals (including some endangered ones) also voted their support. Rare butterflies, snakes and birds increased dramatically. When the first white-tailed deer returned to the North Branch, we felt we were seeing, in all our innocence, another confirmation that our prairies and woods were on the right track. By the time the deer had multiplied out of control and we started shooting them, conservationists considered them an easily understood exception. Deer may be nature, but they were wrecking the ecosystem because they lacked predators.

   The common meadow vole is promiscuous and barbaric. The similar but

   now-rare prairie vole is monogamous and territorial. Is there a clue 

   hiding in these rodents' morals?

Then came meadow voles. Why should they get out of balance? Somme Prairie Grove has a host of vole predators. Red-tailed hawks, great-horned owls, red foxes, and coyotes all feast so heavily on voles that these little rodents have been called “the hamburger of the grassland.”

Then rare plants started to vanish. For some species, when we caged them from the deer, the voles mowed down pretty much every one. Vole numbers follow a “boom and bust” cycle. Could we hope that their devastations were just temporary? But year after year it was the same thing, not just in the savanna but in the very high quality and original Somme Prairie as well. Tom Vanderpoel found the same thing at Grigsby Prairie twenty miles to the west.

   White-footed mice are common at Somme, but we never find them 
   wiping out a species. Why does this mouse “work well with others” 
   while the voles don’t?

Are some species populations being lost because of obscure out-of-balance species? Take the example of the globally-rare eared false foxglove (Tomanthera auriculata). This plant is an annual. It does not sprout again and get another chance next year if its reproduction is foiled. A seed bank may keep producing new plants for some seasons. But sooner or later the last seed will germinate, and the last plant will enter the bowels of a deer or vole, never to feel the sun on its chlorophyll again. At Somme, at least in some summers, the voles eat every foxglove.

We’ve invented “vole exclusion cages” to protect key plants. But there’s a limit to how many species we can protect that way. Every year, for example, every uncaged prairie gentian gets cut before the seeds mature.

What could be going wrong? Certain weasels and certain snakes feed heavily on voles. Those predators are missing at Somme. Should we work to restore them? That could be a compelling challenge! Are there vole diseases or insect pests or other controls that have vanished in these small and isolated sites? Who would study that?

When people, rather than ecosystems, have imbalances, we call it sickness. The fifth most common reason for people to take antibiotics is sinus disease. People with sinusitis on average have nine hundred species of bacteria up their noses. But people with healthy sinuses have more – twelve hundred species. This is another case where diversity is better than control. As Dr. Martin Blazer, chairman of the Department of Medicine at NYU said of human ‘germs,’ “Everyone focuses on the harm. And it’s not that simple, because without most of these organisms we could never survive.”

In ecosystem restoration we tend to restore one species at a time, usually by seeds. We could learn something from an earwax story that’s a favorite of Dr. Andrew Goldberg of U.C.S.F Medical Center. A patient had years of agony from an infection of his left year. He went through many doctors, who prescribed a variety of “antibiotics, anti-mold drops – the works.” Except that nothing did work. Then one day the patient came in smiling and happy.  Goldberg assumed he’d tried another medicine, but no. “I took some wax out of my good ear and put it into my bad ear, and in a few days I was fine,” the patient told him. This was human ecosystem restoration.

When we conservationists rescue a rare plant from the bulldozers at a prairie remnant and move it (and its dirt) to a site under restoration, we copy Dr. Goldberg’s patient. Tom Vanderpoel wondered how the rare Mead’s sedge got to the restored-from-scratch Grigsby Prairie. Then he noticed that each spreading clone of sedge had a hoary puccoon in the middle of it. Tom had rescued the puccoons from a high-quality remnant that was being destroyed. Unnoticed, the rare sedge came along for the ride. So, no doubt, did many species of bacteria, fungi, nematodes, and innumerable others. We don’t study the results of that sort of thing. We should. Not that it would be easy.

The medical quotes in this post are from Michael Specter’s “Germs Are Us – Bacteria make us sick. Do they also keep us alive?” in the October 22, 2012 New Yorker. There we learn that a person has about twenty-three thousand genes. Impressive?  Our human “microbiome” – the bacteria, molds, etc. that live on and in every part of us – has at least four million genes that help us in countless ways. Our bacteria outdo us, gene-wise.

Every plant and animal in the wild ecosystem has something comparable. That means Somme Prairie Grove has a lot of genes. Let’s see: 478 native species times four million genes, give or take a few, yields 1,912,000,000 genes for Somme Prairie Grove.

      For every plant species, a natural area is said to have ten animal species. 

      But then we have to add fungi, bacteria, and God-knows-how-many others. 

Oops, as Ronald Regan would say, there I go again. I forgot the animals. A “rule of thumb” guesstimates that for every plant species an ecosystem has about ten animals species (mostly small of course, but yet part of that petite elite that rules). Thus we compute that a natural area with 478 plant species (and 4,780 animal species) would boast a gene total of a bit over 19 trillion genes. That’s what we save when we’re good stewards. That’s what we lose if we let bulldozers or “the evil shade of buckthorn” eliminate the diversity.  

Next, I find my perspective flipped by Dr. David Relman, professor of microbiology and immunology at Stanford. I’ve long claimed that we need to see ecosystem stewardship as less like physics or chemistry – and more like human medicine. That is, we have to make many decisions based on best expert judgment – when we don’t have certain scientific fact. But Relman was speaking of human health care: “We have to stop looking at medicine as a war between invading pathogens and our bodies,” he said. “This sort of stewardship has more in common with park management than it does with our current practice of trying, in the broadest way possible, to kill microbes.”

Caring for our bodies is like ecosystem management? Well, of course it is. But here’s the implication for our forests, grasslands and aquatics: we have to learn as much as we can, make the best use of specialists (both ‘expert’ specialists and ‘local knowledge’ specialists), and then make the best use of generalists – to decide and act before it’s too late.

Among the Cook County forest preserves, most get no stewardship help, year after year. In the words of one ecologist, "County-wide (and no doubt region-wide) there are many good areas of rich diversity whose figurative fingers are sinking below the waves for the last time." 

That’s why many of us find it so rewarding to work (as volunteers or staff) at this pioneering quest. As one high-schooler said last week at the Solstice bonfire, “We need people winning Nobel prizes in this stuff.” Yes, we do. But some of the needed awards would fit better in the Peace Prize category than in any "hard" science. Conservation needs young new leaders who can span categories and invent ecosystem futures that work.

The Eagles Knew Better

“Many so-called specialists thought this would be impossible,” he said. “The eagles had a different opinion.”

Red deer (elk) and tarpan (horses) in a new wilderness, sort of.

Franz Vera is speaking of the Oostvaarderplassen – an ecosystem reconstruction on 15,000 acres in the Netherlands, 30 minutes from Amsterdam. Vera and colleagues are building a Paleolithic landscape that already includes great herds of mega-fauna including extinct aurochs (giant cattle) and tarpan (original horses), or at least their ghosts, bred back to something like wildness from the most ancient strains that survive.

The white-tailed eagle narrowly escaped extinction. They were said to need mature, tall trees to nest and hadn’t bred in the Netherlands since the Middle Ages. A pair showed up at Oostvaarderplassen and built a nest “nearly the size of an armchair. It seemed ready to topple the scrawny tree it was perched in,” according to an engaging December 24^th New Yorker article by Elizabeth Kolbert.

Experts said they wouldn't show

It feels peculiar for a North American restoration ecologist to read about the Oostvaarderplassen – even though the whole project has its roots here. The “re-wilding” concept was developed by American conservation biologists Michael Soule and Reed Noss, who in turn drew some inspiration from the prairie restoration movement of the Midwest. But what’s so peculiar is the lack of any discussion about plants, in either Kolbert’s article or any of the top Oostvaarderplassen choices on Google.

Many North American ecosystem restorations have been rightly criticized for not paying enough attention to animals. The Oostvaarderplassen work seems all animal. Of course, the Europeans have no counterpart to “natural area” in the American sense. Their quality plant communities were grazed out of existence millennia ago. In some ways the Oostvaarderplassen is a big farm. By winter there’s no grass left, and something like 40% of the charismatic grazers either starve or have to be shot. 

Restoring the aurochs to wild Europe is much like restoring the mammoth to the ancient wilds of North America. 

Oostvaarderplassen has about 1,000 tarpan (horses), 300 aurochs-like cattle, and about 3,000 red deer (elk). They've been joined by huge numbers of geese, egrets, and other birds. Notice the possibly nervous heron, below left. 

No one speaks of restoring the wolf, lion or bear – all wiped out in most of Europe long ago. Of course Oostvaarderplassen, about the size of the Palos forest preserves, is too small for big carnivores.

Enter “Rewilding Europe” – launched three years ago by “two Dutchmen, a Swede, and a Scot.” They have raised six million Euros so far to pursue five rewilding areas - each fifteen times bigger than Oostvaarderplassen. Linked, they’d be enough for big predators. Let us wish them well on this noble quest.  

Wild and Crazy Foxglove

At first it seemed like a restoration attempt that failed. Then, for a while, this partly parasitic beauty just barely hung on. Gradually, we learned to nurture a species that had good reason to be called "wild and crazy."

The eared false foxglove (Tomanthera auriculata) is threatened in Illinois and under review by the U.S. Fish and Wildlife Service for the federal endangered list.

Eared false foxglove – first confirmed near the North Branch by a student of H.S.Pepoon, 
who probably traveled to its habitat on the “Crazy Train.” 

According to the “National Collection Plant Profile” of the Center for Plant Conservation, this species has “About 40-50 known occurrences, most with populations of only 25-250 individuals.” The largest populations are found in Arkansas, Mississippi, and Missouri. Recently discovered in Kentucky. Presumed extirpated in Michigan, New Jersey and Texas.

The species was already rare here in 1927 when H.S.Pepoon published the Flora of the Chicago Region. But one of the three occurrences he listed was a few miles south of Somme at “Dunning” – then a relatively wild and unsettled area. Most people didn’t want to live there, perhaps because it was the location of Chicago’s insane asylum. The main transportation to Dunning was called the “Crazy Train.” This false foxglove may actually be a bit unbalanced itself; the species seems not to do well in settled situations; the little rascal seems to need violent disturbance.

Methods

As we searched for seeds to restore health to depleted ecosystems, we noticed this foxglove in small numbers at three sites in Cook County; at each it seemed to be associated with areas where shrubs had recently been burned back by fire. Fluctuating shrub borders were once a major feature of the tallgrass landscape. Shade from shrubs can kill prairies. When we started with Tomanthera, most prairie managers were trying to wipe out shrubs completely.

We wondered if this species might have a role in the savanna dynamic (Packard 1988). We collected a few seed capsules from a few plants south of Dunning. We broadcast that seed in areas of Somme Prairie Grove that seemed similar to where we found it and had similar plant associates to those listed by Swink and Wilhelm (1994). A few years later we heard from Ron Panzer that a large population near Midlothian was about to be destroyed. Panzer provided us with about one quart of seed capsules, and we broadcast that seed where a few of the Dunning plants had bloomed – and similar areas.

Date of the First Seeding

Oh, yes, it would be great for this report if I could find recorded dates and details of those first plantings. I can’t, so far. I do remember that they happened.

Tomanthera’s seeds are odd and fragile looking, yet they survive in the soil 

and germinate after many years. What’s with the honeycomb effect?

A 1988 reference in Natural Areas Notes suggests that I may have sowed the seeds that early. I was collaborating then with Gary Horn, a fellow volunteer steward and an animal keeper at Brookfield Zoo. He carefully managed a “south of Dunning” site. We had just started to burn that newly discovered prairie, and the foxgloves popped up next to some burned shrubs. Gary has sharp eyes, and he discovered that deer were eating all the foxgloves before they could set seed. So he tried some recommended deterrents: he scattered human hair near the plants (a failure) and then lion hair (also failed). He finally succeeded with his ‘ultimate weapon’ – leopard dung. According to Gary, “Leopard dung has a smell beyond imagining.” He reported that his rare plants then flowered and set seed.

The first foxglove entry I can find in the Somme field journal comes ten years later:

“Sept. 4 (1998). Tomanthera auriculata appeared for the first time (although I can easily believe it’s been there previously; it would have been easy not to find it; especially since the flowers fall off by afternoon).”

For five years, no subsequent mention of Tomanthera in my journal – but in 2003 there’s the note:

“August 24. Found Tomanthera auriculata for the first time in years. Also first time in years that that area has burned. 31 plants along old footpath to Circle Grove … scattered up to 10’ from the trail. Also found one plant 2/3 of the way to the Pothole Pond ... Both of these (areas) have now been scythed.”

Here's the translation: An intense fire – scorching a brushy area that hadn’t usually burned – results in thirty-one foxglove plants. And why scything? A scythe is that long-bladed implement that Father Time carries on New Year’s. We had noticed that saw-tooth sunflower and tall goldenrod could become “thugs” – overpowering and eliminating most other vegetation, under some circumstances. In high-quality ecosystems, they’re not common but multiply after disturbances, like a scab that helps heal a wound. In degraded ecosystems, like we’re working to restore, they can get out of hand and prevent healing. In previous experiments, scything these thugs back into balance seemed to have long-term benefits for diversity generally – and especially for some rare plants. Now we started to help out Tomanthera by scything thugs in areas where it used to thrive. We later found that the foxglove sometimes returned years after scything. One good thing about crazy annuals is that seed may lie in the ground for years or decades, waiting for the right conditions.  

In July 2004 eighteen Tomantheras bloomed. So far so good. But a note in my journal that fall indicates that only one plant survived to make seed. That hurts. I remember a foreboding: What’s wrong here? Is Tomanthera doomed – a few plants pop up some years; then they’re gone, perhaps no new seed being made for the future. 

Almost certainly I took half the seed from the one successful plant and scattered it in other likely places. I find no note to that effect, but that's what I would have done with so rare a plant.

In 2005, the data page shows a whopping 75 plants bloomed. Did they survive to make seed? Did I check? No note on that. Certainly I had good intentions - but lots of competing work and only so much time. My comments in 2006 suggest disaster – and a determination to do better.

August 27, 2006: a jumble of rushed words:

“Put out 2 cages and 8 mouse traps for Central Swale population of Tomanthera. (There had been 6 plants on the 25^th. One of them cut off at ground level on the 26^th.) 28^th: 1 short-tailed shrew. 29^th: 1 each deer mouse and meadow vole.”

There my notes stop, but my memory is vivid. Mouse traps? Short-tailed shrew? The battle has just kicked up a notch.

Here's the drama, as it unfolded: On August 25^th I had been excited to find six foxglove plants far from the area where I’d seen them in the past. (Probably I’d broadcast seed in all these areas back when Panzer donated it. Probably the little crazy little devils sense chemical and physical changes that indicate conditions may be right for them. Then they germinate and bloom. If they can set seed, the population may continue. If not, the population flickers out.) When I checked the next day, one of the six had been cut and sectioned. Not only were the deer eating the foxgloves from above; the meadow voles were attacking from below.

Voles are clever. They stay in grass tunnels but drag lofty seedheads down to them. A vole stands up and gnaws through the stem, grabs the new bottom, pulls it down to the ground, stands up, makes another cut, and keeps repeating that sequence until it has a pile of vole-length stems on the ground and the seed capsules down where it can eat them in safety. Hawks eat voles that are not hidden in the tunnels they make through the grass.

So on the 27^th I probably pirated a couple of deer protection cages from some lesser priority species and put out 8 humane Havahart live traps baited with oats, peanut butter and molasses.

Next day, despite my efforts, another stem was vole-cut. Four left. If we could only protect just a few long enough for next year’s seed. I had a dozen snap traps to fight off the mice that otherwise devastated the rare seed we gathered and stored for later planting. But killing the little gerbil-ish rodents in the wild (even with FPD approval) felt different and more ugly. All the same, losing an endangered species population felt worse. However, no voles blundered into the snap traps despite delicious bait. One shrew was in one trap. Next day, another foxglove was gone.

On the 29^th, one vole and one mouse died in traps. But others had avoided Havahart and snap traps to get another Tomanthera. The assortment of contraptions looked insane amidst the nature.

Next day, another foxglove down. Now just two left. I have other things to do in life. I don’t have time for this. But I go to the hardware store and get talked into a package of stinky stuff – blue cakes of foul stench – guaranteed to repel voles. I place four of them around those two vulnerable stems.

Next morning I return, wracked by angst. Yet the scene I see makes me laugh out loud. It’s an oddly free and happy laugh – a laugh of the absurd. I stare down at a little piece of wilderness decorated by 2 big green deer cages, 8 silver Havahart traps, 12 tan and gold snap traps, 4 bright blue stench cakes, and the last two foxglove stems sectioned and lying carnage among the pathetic technology. Every last ripening seed has gone to its doom.

I began to experiment with vole exclusion cages. They are harder to make and harder to install – a cylinder of half-inch metal mesh. I’m hoping they don’t need tops, because voles stay low. One more “to do” during a busy time of year – yet they work. 

Note from 2007: tried spraying repellent on the foxgloves.

2008:, all but three plants were destroyed by voles. Those three plants wore the newly invented vole cages.

An Angel from Darwin or God

Then a human miracle happened. A year earlier, mild-mannered occasional volunteer Lisa Culp asked if there was more she might do. I hardly knew her. She said later that I “baited” her with fringed gentians. Not really. But I did tell her that deer and voles had been eating nearly all of those rare beauties, and would she like to adopt them? Lisa, who sometimes compares herself to “the Energizer Bunny,” made deer and vole cages for every gentian, scores of them, a lot of work.

Lisa was celebrating a year of gentian success and happily preparing for the 2009 gentian season when I laid before her the plight of the foxgloves. She gave it some thought. Then the mass production of vole cages began. In 2009, all large plants were protected. Probably as a result, in 2010 Lisa had the great pleasure of being witness to a huge surge of foxgloves 178 plants – too many to cage – even for Lisa. Still, she caged scores of them.

Is this too much meddling with nature? I sympathize with whoever answers yes. To land managers and stewards who don’t want to do it, I say, “Great. Your site tests the No Heroic Action alternative.” Yet the effort seemed good to us. Can it be judged by the results?

2011 – now numbers have blown through the roof. 719 plants. Still caging as many as we can.

The graph below shows this population limping along in very low numbers for many years. Then it seems to explode. By 2012, we’re thinking that we may be “over the hump,” and perhaps so. But after you pause for a happy look at the graph, see concerns below.

In one big way, 2012 was a failure!  This year we rested on our laurels. We caged just a few. We concentrated our energies on other species. Voles ate most Tomantheras without a vole cage – many hundreds. We also lost about half the caged ones, probably to white-footed mice. (Voles stay on the ground, but the rascally white-foots are great climbers.) Maybe some foxgloves make so much seed that losing 95% of the plants is good enough? Many species on the planet lose most individuals – to something or other – and still prosper. Is it even possible that critters actually help distribute seed in some way?

Our decades-long study was gloriously imperfect. It had to outlast changes in jobs, places of residence, life goals, etc. This account suffers from some lost data. But it sure beats doing nothing – or those neat and complete little studies of a year or two. Let me revise that: it offers something that shorter and “more scientific” studies don’t.

Next steps for the foxglove at Somme? We’ll continue to ask advice from the best experts we can find. We’ll probably broadcast the much-increased amounts of seed in various areas and record as best we can what seems to be happening under various management regimes. At some point, probably, we may just tell Tomanthera to sink or swim without our help. It will find niches, or not, and persist, or not. Best of luck, Tomanthera auriculata.

Speaking of "next steps" - a 2024 update on this 2012 post is here. 

Credits

Principal credit for the success of Somme’s eared false foxglove in recent years goes to Lisa Culp who does most of the caging. She reports that she makes 16 vole cages per hour.

Great credit also goes to Forest Preserve District of Cook County fire manager John McCabe who has vastly improved the controlled burn program in recent years.

Thanks to Karen Glennemeier, Ron Panzer, Gary Horn, John Balaban, Bernie Buchholz, Linda Masters, Steve Flexman, Robbie Sliwinski, Doug Chien, Lisa Culp and many others for edits and for their contributions over the years.

Photos by Lisa Culp

References:

Center for Plant Conservation: www.centerforplantconservation.org/Collection/CPC_ViewProfile.asp?CPCNum=6601

(Note that scientific names change, and Tomanthera is also called Agalinis.)

Cunningham, Maureen and Patricia D Parr, Successful Culture of the Rare Annual Hemiparasite Tomanthera aurucularta (Michx.) Raf. Scrophulariaceae), Castanea 55(4) 266-271. DECEMBER 1990

Packard, Stephen, 1988, Rediscovering the Tallgrass Savanna of Illinois:

digicoll.library.wisc.edu/cgi-bin/EcoNatRes/EcoNatRes-idx?type=div&did=EcoNatRes.NAPC10.PackardSavanna&isize=M

Swink and Wilhelm, Plants of the Chicago Region, 1994.

END NOTES

1. If anyone who lives nearby would like to help on this (or some other) rare species, let us know through “Comments” here or “Contact us” at www.sommepreserve.org. There are lots of great experiments to try for anyone who finds this work compelling.

2. Some people think we should not reveal the locations of rare plants. They may be right. There’s danger of misbehavior if rare species locations are not kept within a limited community. Botanical psychopaths may steal plants or seeds from known populations. They may degrade, damage or destroy other populations or ecosystems as they indulge in “copycat” vigilante efforts of their own design. But secrecy can also kill. We need to build constituency and enthusiasm for endangered species work; we need our ideas enriched by broad discussion. Overall the best results may come from empowering more conservation than can possibly be done by the grant-driven scientists and plodding bureaucracies that, bless their hearts, do most now. This argument suggests the need for “wiki” type safeguards, ethics, and communication. Your thoughts?