Prairie Remnants at Pleasant Valley Conservancy

Before restoration began, the south-facing slope contained isolated areas of prairie remnant, but was being rapidly invaded by red cedar and other trees, as well as invasive shrubs such as buckthorn and honeysuckle.. Also, a former owner had planted red pines.

 

The south-facing slope in the early 1980s. At this time, restoration had not been considered.
 
South slope prairie remnant (Unit 1) in early summer 2008, 10 years after clearing. See below for history
 
 
The prairie remnants on the south-facing slope responded dramatically to clearing and burning. This is a view two years later. The grass on the upper slope is little bluestem. Seed collecting here (Kathie Brock with the bucket) provided important species for planting elsewhere on the Conservancy.
 

Even after extensive agricultural development, the hill country of southwestern Wisconsin had extensive prairie remnants. These were mainly on steep south- or southwest-facing slopes, generally far from the barn so that cows reached them rarely. Most of these remnants can be seen on early air photos, but they are almost all gone today. The principal reason for their demise was that farmers quit burning the hills, and red cedars, which are fire sensitive, began to develop and eventually obliterated the prairie vegetation.

Recent surveys made in southwestern Wisconsin using air photos revealed numerous unwooded areas that could have been prairie remnants. However, visits to these sites generally showed that the prairie vegetation was depauperate or essentially nonexistent. Only a few percentage of these sites retained prairie vegetation, and those with "good" prairie species were very few in number.

The south-facing slope as a large prairie remnant

Fortunately, at the time restoration began (February 1998) the south-facing slope at Pleasant Valley Conservancy was still partly open, leaving many prairie plants intact. A deer trail across the middle of the south slope (still present and now called the Diagonal Trail) provided access to this area. In summer, side oats grama and little bluestem still existed in scattered patches.

We are fairly certain that the south slope was burned frequently, probably annually, which kept the site open and generally brush-free. The on-the-ground photo below, taken about a half-mile away in 1936, shows the south slope clearly. This photo coincides well with the 1937 air photo.

However, burning probably stopped in the mid 1950s, about the time Harold Lockwood died. After that time, the south slope gradually filled in with brush and trees, although with still many small open areas.

Part of an on-the-ground photo taken by Edith Jones for a Norman Fassett class project (Spring Flora of Wisconsin, 1936), found in the Herbarium archives at the U.W. Madison Botany department.
 

Later observations and historical data indicate that the south slope was grazed, and the grass was mostly native little bluestem:

  • Distinct cattle tracks can still be seen across the south slope after burning and during light snow in the winter.
  • A fence can be seen in the air photo that sits diagonally across the south slope, from the edge of the quarry to Pleasant Valley Road. This fence kept the cattle from wandering over the edge of the quarry. It also kept them from grazing in this area, where grazing-sensitive plants such as prairie dropseed and lead plant are still present.
  • A fence can be seen along the bottom of the south slope, just above Pleasant Valley Road, in the photo of the person with a horse shown below.
  • Except for a few areas, the grass on the south slope is primarily little bluestem, with smaller amounts of Indian grass and side oats grama. There is very little smooth brome. It seems likely that the main fodder for grazing animals was little bluestem.
  • Once brush clearing was completed and annual burns were instituted, little bluestem flourished, and it is now the dominant grass on the south slope. This site is now a classic "short-grass prairie."

 

Near photo taken in February 1968, showing the generally brush- and tree-free south slope. The Rocky Overlook is visible at the top. Note the fence along the bottom of the slope, indicating that this area had been grazed. This slope was probably burned annually. Photo courtesy of Harlan Samson.

The south slope after restoration

After 15 years of annual burns, the south slope has become a very fine short-grass prairie, with little bluestem dominating, as the October 2010 photos below show.

 

Original prairie remnants present at Pleasant Valley Conservancy before restoration began

 

 


Two remaining small but high quality prairie remnants

When restoration work began, Pleasant Valley Conservancy had two small remnant prairies that had remained more or less intact in spite of the absence of fire. On the vegetation map, these are units 1 and 4. Both are on the steep south-facing slope and both would traditionally have been called "goat prairies". (The term "goat prairie" refers to a hill so steep that only goats would graze upon it.)

We often visited unit 1 before restoration work began, enjoying the early show of bird's foot violet (Viola pedata) and wood sorrel (Oxalis violacea). Other characteristic prairie plants were purple prairie clover (Dalia purpureum), prairie dropseed (Sporobolus heterolepis), lead plant (Amorpha canescens), and whorled milkweed (Asclepia verticillata).

This Unit was first burned in 1997, after the cedars had been removed. Both the forbs and grasses responded dramatically, as the photo below shows.

 

The early spring display of bird's foot violet (Viola pedata) on Unit 1 is spectacular.
Unit 4 is an interesting prairie remnant because it was completely hidden from view by woody vegetation, especially buckthorn and red cedar. We only discovered it by viewing the south slope from across the wetland on County Highway F. After seeing this open area from a distance, we bushwacked through the thick underbrush to see what was there. Here, high and isolated, was a large patch of Indian grass (Sorgastrum nutans), with small amounts of lead plant (Amorpha canescens), little blue stem (Schizacyrum scoparius), and side-oats grama (Bouteloua curtipendula). After a good burn of this tiny remnant, a nice population of Indian grass developed, and became our seed source for planting other prairies.

 

Unit 4 as it was in 1998, after a burn but before any clearing had been done. The Indian grass was very lush and was the source of all the seeds of this species planted elsewhere on the Conservancy. After all the shrubs and invasive trees were cleared from the edges, this prairie became linked up to the rest of the south-facing slope.

After a few years of burns in Unit 4, a threatened species, prairie turnip, turned up (see photo, below). A diamond in the rough!

The species lists of these two small remnant prairies are given in the tables below.

Other areas on the south-facing slope, units 2, 3, and 6, were mostly wooded but still had scattered prairie plants. They were the first units to be cleared when restoration began.

 

 
Plants found on prairie remnant (Unit 1)
 
Latin name
Common name
1 Amorpha canescens Lead-plant
2
Andropogon gerardii
Big bluestem
3
Anemone cylindrica
Thimbleweed
4
Antennaria neglecta
Field pussytoes
5
Aquilegia canadensis
Wild columbine
6
Asclepias verticillata
Whorled milkweed
7
Aster oolentangiensis
Sky-blue aster
8
Bouteloua curtipendula
Side oats grama
9
Campanula rotundifolia
Harebell
10
Dalea purpureum
Purple prairie clover
11
Desmodium canadense
Showy tick-trefoil
12
Desmodium illinoense
Illinois tick-trefoil
13
Erigeron pulchellus
Robin's plantain
14
Erigeron strigosus
Daisy fleabane
15
Eupatorium altissimum
Tall (Upland) boneset
16
Euphorbia corollata
Flowering spurge
17
Geranium maculatum
Wild geranium
18
Kuhnia eupatorioides
False boneset
19
Linum medium texanum
Small yellow flax
20
Lithospermum incisum
Fringed puccoon
21
Monarda fistulosa
Wild bergamot
22
Oxalis acetosella
Northern wood-sorrel
23
Oxalis violacea
Violet wood-sorrel
24
Panicum latifolium
Broad-leaved panic-grass
25
Panicum sp.
Small-seed panic grass
26
Ratibida pinnata
Yellow coneflower
27
Rudbeckia hirta
Black-eyed Susan
28
Schizachyrium scoparium
Little bluestem
29
Scutellaria leonardi
Small skullcap
30
Sisyrinchium spp
Blue-eyed grass
31
Solidago canadensis
Common goldenrod
32
Solidago nemoralis
Old-field goldenrod (grey; dyer)
33
Sorghastrum nutans
Indian grass
34
Sporobolus heterolepis
Prairie dropseed
35
Tradescantia ohiensis
Common spiderwort
36
Verbena stricta
Hoary vervain
37
Viola pedata
Bird's foot violet

 

   
Plants found on prairie remnant Unit 4
 
Latin name Common name
1 Agastache nepetoides Yellow giant hyssop
2 Amorpha canescens Lead-plant
3 Aster ericoides Heath aster
4 Aster oolentangiensis Sky-blue aster
5 Bouteloua curtipendula Side oats grama
6 Eupatorium altissimum Upland boneset
7 Kuhnia eupatorioides False boneset
8 Lithospermum canescens Hoary puccoon
9 Lithospermum incisum Fringed puccoon
10 Monarda fistulosa Wild bergamot
11 Oxalis violacea Violet wood-sorrel
11a Pediomelum esculentum Prairie turnip
12 Rudbeckia hirta Black-eyed Susan
13 Schizachyrium scoparium Little bluestem
14 Senecio pauperculus Balsam ragwort
15 Sisyrinchium spp Blue-eyed grass
16 Solidago nemoralis Old-field goldenrod
17 Sorghastrum nutans Indian grass
18 Sporobolus heterolepis Prairie dropseed
19 Viola pedata Bird's foot violet
20 Viola pedatifida Prairie violet
South slope prairie remnants in early summer 2008, 10 years after clearing,

Other prairie remnants

In addition to these larger sites, a number of smaller prairie remnants existed at Pleasant Valley Conservancy at the time restoration work began. Most of these were areas that had not been plowed, or had been too far from the barn for much grazing. Some of these remnants were important because they were the sources of seeds of particular prairie species. Here is a list:

  • An unplowed area at the north end of Toby's Prairie which had (and still has) a fine population of white wild indigo (Baptisia alba).
  • An unplowed area at the southeast corner of Toby's Prairie (which we call Toby's Annex). This had (and still has) a fine population of showy goldenrod (Solidago speciosa), plus Missouri goldenrod, round-headed bush clover, and flowering spurge, all of which were used as seed sources for restoration work.
  • An open area at the southeast side of Unit 11A which had small amounts of lead plant and New Jersey tea. This area responded to restoration and further plants of these two species have developed.
  • Two areas in Unit 12A, one in the southeast corner, near the ravine, which had a fine population of great blue lobelia (Lobelia siphilitica) and Lobelia inflata; one at the top (northeast) corner which had (and still does) a fine population of shooting star (Dodecatheon meadii). The Lobelia sp. have mostly disappeared as the savanna area has been opened up, presumably because the area is now too dry.
  • An area at the southeast corner of Unit 18 which had (and still has) a large population of spiderwort (Tradescantia ohiensis) as well as some Virginia wild rye (Elymus virginicus). This was an area that had a large population of black walnut (removed in the winter of 2000-2001). Walnut produces juglone, a plant toxin, but both spiderwort and rye are known to be resistant to this, which probably explains why they were able to maintain themselves in this area.
  • The road cut of County Highway F, which has a large number of mostly savanna species, and served as an early seed source for restoration work. This road cut is now under protection from the county mowers and is maintained by Pleasant Valley Conservancy staff.
  • In addition to these "remnants", there were a number of other native species scattered here and there across the Conservancy and served as sources of seed for restoration work, such as glade mallow, purple milkweed, poke wilkweed, swamp milkweed, whorled milkweed, Kuhnia, tall boneset, Illinois trefoil, cup plant, blue vervain, Kalm's brome, etc.

Seeing this summary for a property that some people had considered too degraded to restore, makes one realize that there is good hope for many other so-called degraded sites!