July 9, 2017: Restoration Tour of Somme Prairie Grove

Michigan lily can be found in woodland, savanna, or prairie. In times of lower deer populations, 

a single stem may have ten or twenty blooms. This year most had just one - a barometer of deer numbers. 

The Somme Facebook sites announced a tour with a limit of twenty people. Great people came. We decided to divide into three small groups for good discussions. Leaders: Eriko Kojima, Linda Masters, and Stephen Packard.

This post is mostly the “script” we prepared for the walk. We invite you to take this walk virtually - or bring these notes with you as you hike the trail.

To make it easier to find the numbered focal points, they are forks in the footpaths. 

POINT 1: Introduction

The Somme preserves harbor 501 native plant species. These include 17 on the Endangered or Threatened lists (ten present when we started and seven restored from other remnants) and many other uncommon or rare plants and animals. Of the plant species, 141 are thought to be “restored” from other remnants (some now destroyed) by seeding. But more important than the individual species, this area and its stewards conserve and restore a rare ecosystem.

Conserving original “Natural Areas” is a new concept – partly originating with the Illinois Natural Areas Inventory of the 1970s. Eastern states basically don’t have them (except for species that live in places like bogs and mountain tops). All their good soil was transformed into agriculture or some other “biodiversity challenged” state long ago. Somme Prairie Grove is one of the first places on the planet where an attempt is under way to restore remnants of a nearly vanished natural community – the black-soil bur oak savanna.

 

A major challenge at Somme (and so many natural areas) is too many deer.
These beautiful animals are a natural and valuable part of the ecosystem.
But in the absence of predation excessive numbers can badly damage the habitat for many other species.

We walk today entirely in the area burned this spring. This is much richer and more flowery than unburned areas. (The north half was unburned this year but was burned two years ago.) Lightning (and, in the last few thousand years, indigenous people) ignited the fires which shaped these species and this type of community for about five million years. The savanna we now call Somme Prairie Grove was here for thousands of years evolving into what we today call a natural area following the last glaciation, 12,000 years ago.

Waukegan Road follows the crest of the Deerfield Lobe of the Lake Border Moraine. To the east, at one point, was Glacial Lake Chicago. But we’ll be walking on the western slope of the moraine, going gradually down the whole slope.

In this first section, we’ll be walking through a young restoration of wet prairie with too much big bluestem grass and impressive amounts of tuberous Indian plantain and smooth phlox. When we go up a slight rise, as we get closer to the trees, there will be drier ground with the more conservative prairie dropseed grass (shorter tufts of thin leaves). Then we go past natural shrub thickets and into a woodland with some old bur oaks and shagbark hickories. Restoration here started with removing dense buckthorn, but the grove is still overly shady with too many young pole trees, that became over-common in the decades without fire. (We started burning the woodlands here in 1985.) It's a young restoration (most parts less than three decades old), and much is still unbalanced. 

Most Midwestern woods today are degenerate. They are so dark (from lack of natural fire) that few summer or fall grasses or wildflowers survive. Few or none of the oaks that make up the canopy are reproducing. This woods was colorful during spring. Today, early summer, is an ‘in-between’ time, with  ripening spring seeds of sedges, trilliums, etc., but few showy flowers. Soon though, it will be flowery again and will have many waves of different kinds of wildflowers and grasses blooming all the way through September and into October. Birds that have returned to breed in these woods include wood pewee, flicker, indigo bunting, and scarlet tanager.

POINT 2: To restore complexity, it can help to understand some of it.

Here we start to see a great diversity of flowers and grasses. Indeed, we’re on the edge of a big patch of the unusual shrub, New Jersey tea (Ceanothus americanus), mixed with blooming butterfly-weed, wild quinine, leadplant, rattlesnake master, flowering spurge, and compass plant.

This tea has history. It got the name “revolutionary tea” when adopted by the patriots after they threw the British tea into Boston Harbor. Its known history in modern Somme started with a few plants that grew under the trees just south of this fork in 1980 when we started the restoration. We learned to germinate the tea’s unusual seeds by pouring boiling water over them. We did not learn to inoculate those seeds with the needed Frankia bacteria, and our plantings of this species did poorly. The new plants seemed to do okay for some years but gradually fade out.  (Like legumes depending on a Rhizobium bacterium to fix nitrogen, New Jersey tea has a similar symbiotic bacterium on which it depends.)

 

"Revolutionary tea" became historic after the British tea landed in Boston Harbor.
It's history here has its revolutionary aspects too. 

On the other hand, in this area, where we did not help the New Jersey tea, it has prospered beyond all expectations. The patch has spread to the north and northwest for about fifty yards and now includes many hundreds of thriving shrubs. This year we started experimentally to spread the soil from the roots of the main patch to some recently emerged plants in other parts of the preserve, to see if they will benefit. (The original plants have died out near the trees, as the patch spread. Why?)

Entomologist Dr. Ron Panzer says that New Jersey tea is a highly valuable nectar plant for many bee and butterfly species.

Our inter-seeded former pastures are now much richer than areas where we cut the brush and seeded bare soil.

As we walk to the next point we’ll pass through some quality restoration areas, where seeds were broadcast long ago, and some poorer areas, where they weren’t. Notice patches of shrubs (gray dogwood) – some of which have been “top-killed” by fire and are re-sprouting.

Keep your eyes open for some Michigan lilies in bloom.

Just before entering the next woods, we’ll walk through a large area of mostly just big bluestem grass – poor diversity. Inter-seeding is needed here to restore higher quality.

POINT 3

This is a young woodland restoration. Both the trees and the planting of understory grasses and wildflowers are new.

Note flowering Michigan lily here in the woods. This is one of many species that are not limited to one habitat; you’ll find them growing in high quality prairies, savannas, and woodlands. Others include shooting star, wood betony, and golden Alexanders.

Young bur oaks are a special feature here – largely absent from many original bur oak woods or savannas. (Bur oaks are not successfully reproducing in most places because invasives make it too dark.) Some of the quality plants that were originally in this scrappy-looking little woods include Michigan lily, purple milkweed, Kalm’s brome, and woodland puccoon.

As we walk to the next point, we’ll pass through high quality grassland with an abundance of smooth phlox, prairie dropseed, and little bluestem. Then we enter a shrub patch we call “The Bird Thicket” – which has been a special focus of restoration in recent years. Birds that are regularly seen here during the nesting season include ruby-throated hummingbird, orchard oriole, kingbird, brown thrasher, yellow warbler, and indigo bunting. 

We walked through dense patches: smooth phlox, then New Jersey tea, then prairie clover.
A week later, many of today's flowers will be replaced by maturing seeds.
Years later, many of these patches will have spread out and mingled with each other. 

The Bird Thicket was mostly buckthorn – and indeed it still is. But had nannyberry, black haw, prickly ash, wild plum, Iowa crab, hawthorns, young oaks, sumac, gray and silky dogwood, and many species of roses. Natural thickets have been almost entirely wiped out everywhere by buckthorn etc. Few attempts are under way to restore them.

 

Oaks here were not reproducing, in part because deer ate them down to foot-tall shrubs. Exclusion cages (as above) protected saplings from the deer. But fire remained a challenge (note leafless outer limbs from this spring's fire).
Over the years, these classic savanna trees gradually surmount deer and fire pressures and become maturing bur oaks.

Quality herb vegetation here includes cream gentian (Gentiana flavida) and slender wheatgrass (Elymus trachycaulus) (endangered). 

POINT 4

We’ve just passed through some rich restoration, but this area immediately around this trail intersection is poorer. It received little or no seed, and is probably improving its diversity very slowly from chance arrivals of new species. 

Notice an area of low-statured plants a few yards northwest of the trail intersection. This area was a patch of big bluestem that had spread to a dozen or so yards across, with little or no other diversity in it. We were concerned about areas like this, which are typical of poor restorations. The path divided this patch in two. As an experiment, we seeded both sides equally and repeatedly scythed away the tall grass from only the west side of trail. We wondered whether the mowing would handicap the over-abundant big bluestem and foster more diversity. For many years, it seemed that the mowed side of the trail was getting much more diverse, and the un-mowed side was not. Certainly, the shooting stars and prairie betonies are much more common on side that had been mowed for a few years. But looking today at the un-mowed side, it too is getting more diverse, with prairie clovers and other quality species. This has been and will be an interesting area to watch over the years.

On the way to the next point we’ll pass three plants of New Jersey tea (can you spot them?) Also purple and (the less common) white prairie clovers (Dalea purpurea and candida). In the early years of restoration, we found very little white prairie-clover seed to broadcast, and the little we found didn’t seem to do very well. But in recent years the white seems to be increasing at a rapid pace – perhaps because it competes better among higher-quality associates? In this 1927 book, H.S.Pepoon commented that the white prairie clover was “ordinarily more common.” Today white prairie clover is rarely found, except in a few very high quality prairies. Will the white catch up to the purple in this savanna over time?

 

The rare white prairie clover increasingly competes with the only-slightly-less-rare purple.

Also along this path notice Canada milk vetch in bloom. Notice also the rich bronze – short clumps of June grass in seed.

POINT 5

Now we’re near the bottom of the moraine (near the West Fork of the North Branch of the Chicago River). From here west, all the trees you see were invaders (or planted before the era of prairie and savanna restoration). From this spot two hundred years ago (and perhaps two thousand or five thousand years ago) – unbroken prairie stretched to the horizon.

The former pastures in this area have responded especially well to restoration. They started with a kind of diversity – mostly of such “old field” species as the blue grasses, timothy, poverty oats, goldenrod, daisy, etc. (They may also have retained some of the soil biota that was lost in the darker shade of brush?) Here we broadcast rare prairie seed right into the that “weedy” turf. Diverse species thrived, as you see. In contrast, in areas where we cut the former brush and seeded into bare ground, progress toward quality has generally been slower. But some rare species have done especially well there, for now at least.

 

Milk vetch and other species that spread by roots has often done best in former brush-cut areas. 

Also note many burned-off (last spring) and re-sprouting bur and scarlet oaks and hazelnut shrubs. These species are typical of savanna rather than prairie. Other common species here that suggest savanna rather than prairie include cream gentian, purple milkweed, Maryland snakeroot, carrion-flower, and purple vetch.   

POINT 6

Here we see distinctly morainal topography. The soils are probably gravelly. Savannas were especially common on the moraines. Many plants in this area may be more typical of savannas – or at least we don’t find them so often in the woodlands or prairies at Somme. These include Seneca snakeroot, grove sandwort, meadow parsnip (Thaspium trifoliatum), yellow false foxglove, wild licorice, savanna blazing star, robin plantain, wood rush, and rue anemone.

As we walk to the next point, notice starry campion and wide-leaved panic grass in the open area – and then when we enter the woods, notice such now-uncommon plants as: long-awned woodgrass, blue-stemmed goldenrod, woodland puccoon, woodland thistle, and woodland milkweed.

POINT 7

(This point is where the stream crosses the path.)

 

This oak woodland is the focus of the book “Miracle Under the Oaks” by New York Times science writer William K. Stevens. There are no large old trees in the water course. We also see this lack of old trees in the wetter areas along some of the water courses in Somme Woods. It could be that during some fires there was so much heat from the lush grasses and sedges in the wetlands that trees burned off.

All the biggest old trees in the grove (indeed in all of Somme Prairie Grove) are bur oaks. This oak has the bark and trunk best adapted to withstand hot fires. Another original oak here, scarlet oak or Hill’s oak, is naturally a tree that burns off and re-sprouts indefinitely, often acting like a shrub. The huge old Hill’s oaks in the grove may be mostly a result of fire suppression.

 

We had thought heart-leaved Alexanders (Zizia aptera) was gone from the site. But we found a few likely leaves,
 caged them, and the caged plants came roaring back. Careful use of management techniques like caging, fire,
thinning pole trees, seed introduction, and deer control are central to the stewardship of this site. 

Conclusion: Somme Prairie Grove is an experiment – a test of how much largely self-sustaining natural biodiversity it is possible to restore for an original black soil savanna (and associated prairie, woodland, and wetland patches). A very high quality (“Grade A”) or even high quality ("Grade B”) remnant of this kind of natural area no longer exists on the planet. The words “largely self-sustaining” represent part of the experiment. Stewards will certainly need to control fire and deer for the foreseeable future. But we hope that weed-pulling, planting, and caging are just temporary needs. The Somme experiment will take decades to mature – but results are already promising.

One of the three tour groups that contributed ideas to this post.
They are pioneers - as are all of us involved in the early years of the discipline of ecosystem conservation.

We stewards appreciate your interest. We appreciate the dedication of all partners. Anyone who might like to help is invited to attend our “workdays” or take on a special project – as many people have.

Post script: Other interesting plants in bloom along the trail today: glade mallow (Napaea dioica), great St.Johnswort (Hypericum pyramidatum), pale Indian plantain (Cacalia atriplicafolia), prairie Indian plantain (Cacalia tuberosa), winged loosestrife (Lithrum alatum), prairie loosestrife (Lysimachia quadriflora), and fringed loosestrife (Lysimachia ciliata).
(Our apologies for not-the-latest scientific names in some cases.)