The remarkable document below reflects 37 years of dedication to an important, neglected ecological treasure. It was produced by Dr. Wayne Schennum (1949 - 2021).
Bur Oak and Lead Plant, Moraine Hills State Park, summer 1983
Introduction
Moraine Hills State Park is noted for its outstanding representation of geological formations and high quality wetland communities. The complex array of glacial kettles, kames, and narrow moraine ridges here is one of the best illustrations of glacial activity in the Northeast Morainal Natural Division of Illinois (Schwegman et al 1973) This recognition led directly to their purchase by the Illinois Department of Natural Resources. The kettle hole wetlands, including a bog, a deep lake, and complexes of marsh, sedge meadow, and fen communities, clearly represent the original vegetation of the region and have been recognized as natural areas of statewide significance via the preparation and execution of scientifically based management plans and dedication as Illinois nature preserve (McFall and Karnes 1995).
Much less attention has been directed at the timbered upland sections of the park, both within and outside of the nature preserves. Because these woodlands were extensively grazed by domestic livestock (Marlin Bowles, pers. com.), and logged, they were not recognized by the Illinois Natural Areas Inventory as representative of presettlement conditions. Given the cessation of grazing 55 to 60 years ago, these timbered areas have had some time, and potentially ecological capacity, to restore themselves to presettlement conditions.
In the late 1970’s, following the opening of the park, I noticed while walking the main trails that small patches of russet-colored prairie grasses remained among the trees on the slopes of gravelly ridges. I walked into the timbered areas and found a mixture of a few prairie plants and others tolerant of partial shade. At the same time, Steve Packard found enclaves of prairie and savanna plants amongst the trees of Cook County Forest Preserves along the North Branch of the Chicago River (Stevens 1995). I took Steve to Moraine Hills State Park to show him what I had found. He immediately recognized the similarity of the herbaceous flora there to what he had found in Cook County. We both agreed that aggressive management could restore this unique floral combination to a richer community of open timber and grass similar to what early pioneers described in the Government Land Survey Notes, diaries, and technical reports.
In 1982 – 1983, I launched a study to determine the degree to which selected timbered areas of the park represented presettlement communities, the successional trends beneath and between the oaks, and the management schemes necessary to maximize plant diversity and restore a natural community that had been a dominant feature of the landscape in the early 1800’s but had all but disappeared since then (White 1978).
The purpose of the study here is to evaluate the composition, structure, and community type(s) here in 2018, and compare these features, both quantitatively and qualitatively, with the results of the 1983 research (Schennum 1983)Since considerable efforts over the last 35 years – burning, brush removal, exotic species control, deer hunting, and rare plant monitoring – has been accomplished by volunteers, IDNR staff, and contractors, the second major purpose is to evaluate the impacts and effectiveness of these management practices, and to recommend future restoration needs.
Methods
There are many timbered areas that qualified as potential study sites. Based on qualitative evaluations of the flora and vegetation as a whole
five areas were selected in the northern half of Moraine Hills State Park. They are mapped in Figure 1. They correspond precisely to those chosen in 1983) (Schennum 1983). Areas A, B, and C lie in the Leatherleaf Bog unit of the Kettle Moraine Nature Preserve west of Lake Defiance on rolling glacial outwash. Areas D and E are in an undedicated part of the park characterized by a chain of steep delta kames known as the Fox Lake Moraine (McFall and Karnes 1995) (Willman 1971). A park map showing the locations of each of the 5 units is presented in Figure 1. The soils of all 5 areas are derived from gravel and gravely loam outwash A map of the soils which shows both soil types and slopes is given in Figure 2.
The following data were taken during the 2016 – 2018 growing seasons:
· Season long plant inventories were conducted on all 5 units. For each species an estimate of relative abundance was assigned on a scale of 1 to 5: 1 = rare, 2 = infrequent, 3 = frequent, 4 = common, 5 = abundant (usually dominant). This method was used during both statewide natural areas inventories, one in 1976 - 1977 (White1978)) and one in 2008 – 2011 (IDNR 2006). After all plant data was digitized, it was analyzed using the evaluation system given in (Wilhelm and Rericha 2017). In addition to the variables used in this book, the % conservative species was calculated for each unit, where conservative plants were all those with coefficients of conservatism greater than 5.
· Several colonies of the state threatened Pale vetchling (Lathyrus ochroleucus) were monitored in 2017 in Units B, C, and D using methods developed by the Plants of Concern program for the Chicago Wilderness Region (Chicago Wilderness Coucil 1999).
· Some field notes were taken of the structure and composition of the vegetation on all field visits.
· A quantitative canopy study was done for Units A through D. In these units a starting point was selected at the south or north end of a 100-meter transect. A GPS reading was taken at the start point. At this point and 5 subsequent ones at 20-meter intervals a random number was selected from a table of such numbers from 0 to 9. Alternating from right to left, etc., a distance equal to the random number was measured and a point selected for a sample plot. From that point a circle with an 8.92-meter radius was used to define a circular plot in which the diameter at breast height (dbh) and species name was recorded for all trees whose dbh was 10 centimeters or more. This information was recorded on standardized forms, and the data was then stored in digital format.
· In fall of 2018, some data was taken on shrub/sapling density and canopy coverage of mature trees in a set of plots in Unit C. For the latter, 2 measurements were made of the lateral extent of two branches from the bole of each tree > 10-cm dbh in 4 plots the same size as those in the canopy sampling and 20 meters apart along an 80-meter long transect. These were later averaged and the total area of canopy coverage calculated as the sum of areas for each tree. For the shrub/sapling density, the number of stems > 10-cm in height and less than 10-cm dbh were counted for each species in a circular plot with a radius of 5 meters. A total of 6 plots, each 10 meters apart, were sampled along the same transect used for canopy coverage.
· Quantitative herbaceous vegetation data was collected on Units C and D only. In Unit C, 2 100-meter transects were layed out on south to north axes. Because of its small size, Unit D’s transects were broken into pieces on 3 east to west lines. Vegetation was sampled in twenty ¼ - msq plots at intervals of 5 meters. Plots straddled or occupied the right sides of the 100-meter tape. Presence and absence was recorded for each species in each plot. No % cover data was taken.
· A single butterfly survey was conducted on July 1, 2018. This study was done by tabulating the number of individuals observed on a 2-hr. random walk from 2:00 p.m. to 4:00 p.m. in Unit C only. Records were kept on standardized forms and the data later digitized.
· Bird surveys were conducted on Units A and B (combined – 11 stops reduced to 9) on 2 dates in early June, and on Unit C (9 stops) on two dates in late June. In each case, a route was established prior to the survey by making GPS recordings of each census stop. Distance between census points was 150 meters, per the standards set by the Illinois Bird Survey Network. On 6/11/18 the survey was conducted from distant points on the trails farther from the original points. Identifications were made primarily by hearing the songs known for each species (DeVore et al 2004). Records were kept on standardized forms and the data later digitized.
Results
Results of the study are presented in map, tabular, and written form for the introductory maps (Figures 1 and 2) and the items listed in the Methods section. Large data spreadsheets are located in the Appendices.
Figure 1 shows that Units A through C are part of a complex of upland woods in a wetland matrix on the west side of the park. Units D and E are bordered by large wetlands on the east side of the park. Units A and D are relatively small compared to Units B, C, and E.
The soil map in Figure 2 shows that Fox and Casco silt loams are the dominant soil types in Units A through C. Since Units D and E have the same dominant soil types, a second map of these units was not prepared. Fox and Casco soils are derived from sandy and gravelly glacial outwash. They develop under wooded terrestrial communities.
Plant surveys and analyses
The results of the plant surveys are shown in Appendix 1 to 6. This rather overwhelming mass of information is summarized in Table 1, which gives for each unit the total # of species, the # of native species, % exotic species, mean C, FQI, and % conservative species. A 6th unit was added and was called the “Island” (last column) as it is the disjunct northernmost part of Unit C and therefore may have been less disturbed by domestic livestock.
Table 1: Species counts, percentages, and metrics, all units
unit | A | B | C | D | E | C - island | |
metric | |||||||
total # spp | 100 | 127 | 161 | 114 | 137 | 97 | |
# native spp | 77 | 95 | 126 | 93 | 100 | 79 | |
% exotic spp | 23% | 25.2% | 21.7% | 18.4% | 37% | 18.6% | |
mean C | 4.403 | 5.000 | 5.040 | 4.9589 | 4.05 | 4.987 | |
FQI | 38.636 | 48.734 | 56.574 | 48.112 | 40.5 | 44.325 | |
% conserv. spp | 21.8% | 26.3% | 34.9% | 29% | 19% | 31.6% | |
area (ac) | 5.2 | 17.6 | 24.8 | .8 | 21.7 | 1.9 |
Referring to Appendix A-1 (Unit A), the most common (relative abundance of 4 or 5) herbaceous plants in Unit A are: Allium cernuum (Nodding wild onion), Carex pensylvanica (Common oak sedge), C. rosea (Curly-styled wood sedge), Hylodesmum glutinosum (Pointed ticktrefoil), and Solidago ulmifolia (Elm-leaved goldenrod).
In Appendix A-2 (Unit B)) the most common herbs are: Amphicarpa bracteata (Hog peanut), C. pensylvanica, Dodecatheon meadia (Shooting star), Galium boreale(Northern bedstraw), H. glutinosum, Smilacina racemosa (Feathery false Solomon’s seal), and S. ulmifolia.
In Appendix A-3 (Unit C) the most common herbs are: A. cernuum, A. bracteata, C. pensylvanica, D. media, Geranium maculatum (Wild geranium), Hepatica americana(Round-lobed hepatica), H. glutinosum, Luzula multiflora (Wood rush), Moeringia lateriflora (Wood sandwort), Sisyrinchium albidum (Blue-eyed grass), S. ulmifolia, and Vicia caroliniana (Wood vetch).
In Appendix A-4 (Unit D) the most common herbs are: A. bracteata, C. pensylvanica, G. maculatum, Helianthus strumosus (Savannna sunflower) H. glutinosum, Schizachyrium scoparium (Little bluestem), S. racemosa, and S. ulmifolia.
In Appendix A-5 (Unit E) the most common herbs are: A. bracteata, H. glutinosumErigeron annus (Annual fleabane), Helianthus divaricatus (Woodland sunflower), S. racemosa, Solidago altissima (Tall goldenrod), and S. ulmifolia.
In Appendix A-6 (Unit C island) the most common or abundant herbs are: Antennaria plantaginifolia (Large pussy toes), Aquilegia canadensis (Wild Columbine), C. pensylvanica, C. rosea, Galium concinnum (Shining bedstraw), M. lateriflora, and S. ulmifolia.
Based on Table 1, the rank order of units from highest to lowest for mean C values is: C > B > Cis > D > A > E. For % conservative species the rank is C > Cis > D > B > A >E. For % exotics the rank (inverse or low to high) is: D = Cis > C > A > B > E.
Notes on threatened Pale Vetchling (Lathyrus ochroleucus) & other rare plants
Populations of the state threatened Pale vetchling (Lathyrus ochroleucus) were monitored during in late May of 2017. I assisted Sarah Schultz in this work since she was most familiar with the sampling protocols. She submitted the data to the Plants of Concern committee initiated in the 1990’s by the Chicago Botanic Garden for Chicago Wilderness. Several colonies were discovered in Unit C, including the Island. Several small colonies were found in Unit D on the edge of the central prairie there. This species was found in limited numbers in Unit B. Colonies in Unit C were often large and had numerous blooming plants.
Five additional plant species that were observed in the woodland surveys are regionally rare and, like the Pale Vetchling, are on Chicago Wilderness’ Plants of Conservation Concern list. These species and the units in which they occur are as follows: Poke Milkweed (Asclepias exaltata) (Units B, C, and E), Wood’s Stiff Sedge (Carex woodii) (Unit C), Robin’s Plantain (Erigeron pulchellus) (C and C-IS), Round-lobed Hepatica (Hepatica americana) (Units B, C, D, E), and Indian Pipe (Monotropa uniflora) (Unit’s B and C). None of these 5 species have been monitored.
Field notes and observations
A number of ecological notes were taken during the 2016 - 2018 biological surveys.
1. The herbaceous layer was relatively homogeneous in composition and structure; no particular compositional shifts with environmental gradients were noted, except in Unit D where the composition and structure change considerably as one shifts from prairie grass dominance to oak and sedge dominance with changes in % shade.
2. Small but significant areas with thin soils and low plant species richness were noted, especially in Unit C; however, the species present tended to be moderately conservative rather than pioneers or exotics.
3. Even prior tto ransect sampling, the most common canopy trees in units A through C, & E appear to be White Oak (Quercus alba) and Red Oak (Q. rubra). Exceptions were noted on dry gravelly knolls within these units and on a very steep dry kame in Unit D, where Bur Oak (Q. macrocarpa), and Black Oak (Q. velutina), are more common.
4. Young (sapling and subcanopy) Red Oaks are scattered in a number of small groves in deadfall canopy openings. Young White Oaks in these layers are very rare. Seedlings of both species are common in these openings.
5. Most canopy oaks are mature second growth and straight grown. Small sunlit openings are scattered and shift positions with the time of day. Canopy trees are relatively dense, so most openings are only partially lit during the daylight cycle.
6. The understory was dominated by exotic shrubs, especially Autumn Olive (Eleagnus umbellata), non-native honeysuckles (Lonicera spp.), and invasive native shrubs and small trees, in particular Gray Dogwood (Cornus racemosa) and Black Cherry (Prunus serotina). In the winter of 2018, contractors and IDNR crews completely removed this understory from all 5 sample units. Follow-up treatment with herbicide was done in the summer of 2018 by a contractor.
7. All woodland units were burned by IDNR staff in fall of 2017 or spring of 2018. Some of the spring burns were conducted late (last week of April). Units A through C were burned in 2016 also.
8. Exotic herbaceous species, though not in high frequency, occur throughout the woodlands. Species richness for such plants is relatively high.
9. Brad Semel determined that deer browsing was reducing herbaceous woodland species’ growth and cover during the mid-1990’s. With my assistance, he selected one of the richest areas for installation of a deer exclosure in Unit C that he then monitored for browsing impacts. Using the information gathered a controlled deer hunting management program was initiated. A positive response was noted for woodland herbs and grasses following a few years of hunting.
10. From mid-summer to fall, the herbaceous layer appears to be
completely dominated by two forbs – Hylodesmum glutinosum
and Solidago ulmifolia. During the earlier parts of the year, no
species dominates the ground layer except Carex pensylvanica.
11. Insect species, and in particular butterflies, appeared to be
infrequent or rare. Butterfly species abundance, richness, and diversity were unexpectedly low.
12 Nectar sources for adult butterflies were uncommon, but
larval host plants were present and often relatively common.
13. During the bird surveys, a number of wetland species, such as
Sandhill Cranes and Great White Egrets were observed or
heard in the bordering marshes.
Quantitative canopy survey
All of the quantitative canopy data for the 2016 – 2018 survey is given in Appendix E Units 1 – 7). There is no canopy data for Unit E, which was dropped because of its high level of disturbance. Ten parameters help quantify the composition, structure, and management needs of the woodlands, Table 2 below consolidates this large mass of data into a manageable summary for these parameters. They are: mean # species per plot, mean dbh per plot, total # of individuals for each of 4 oak species (white, red, bur, black) for mature trees (dbh =/> 20 cm), total # of individuals for the same 4 oak species for saplings/understory (dbh < 20 cm). Note that Unit C is split into 4 independently measured subunits. Lumping of all individuals of all species to calculate the first two parameters for each unit does skew the data in favor of young trees.
Table 2: Summary of woody vegetation survey
unit | A | B | C main | C penin. | C. below island | C island | D |
parameter | |||||||
mean # trees/plot all spp. | 10 | 6.1 | 6.7 | 7.5 | 7.5 | 11.2 | 7.3 |
mean dbh /plot all spp. | 23.3 | 38.8 | 35.2 | 37.4 | 41 | 33.4 | 41.5 |
total # white oaks | 8 | 12 | 38 | 18 | 27 | 12 | 1 |
total # red oaks | 26 | 37 | 16 | 23 | 15 | 31 | 2 |
total # bur oaks | 4 | 2 | 8 | 3 | 3 | 11 | 15 |
total # black oaks | 1 | 0 | 0 | 0 | 0 | 1 | 2 |
# white oak saplings | 0 | 1 | 0 | 1 | 1 | 0 | 0 |
# red oak saplings | 19 | 16 | 9 | 8 | 7 | 24 | 0 |
# bur oak saplings | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
# black oak saplings | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
# plots | 6 | 10 | 10 | 6 | 6 | 5 | 3 |
Seven additional species totaling 45 individuals also contributed to the woody component of the canopy and understory. Only two, Carya ovata (Shagbark hickory) and Prunus serotina (Black cherry) were present in significant numbers at 20 and 18, respectively.
Based on the data in Table 2 and Appendix B, the most common species were White Oak (116) and Red Oak (140). The total number of Bur Oaks was 43. Red and white oaks were the most frequent species in all units except Unit D, where bur oaks were far more common. Red oak was the only species with an appreciable number of individuals in the understory – 83, varying from 7 (unit C below island) to 24 (unit C island). By contrast, White oak, Black oak, and Bur oak had a total of 3, 1, and 0 saplings, respectively. In fact, in units A and C-island, 75% of the Red oaks present were less than 20 cm dbh. The highest percentage of younger White oaks in any unit was 13 in unit C-below island.
Canopy coverage and stem counts
The plot size for canopy coverage was a uniform 250 msq (r = 8.92 m). The results for this parameter are given in Table 3 for Unit C only. Unfortunately, the computations fail to account for the overlap or intersection of canopy and subcanopy trees so it is not possible to just add the canopy sizes for each tree to obtain total coverage. Also, the amount of light allowed by a tree varies between tree sizes and species. Checking plots 3’ and 4’s largest trees and assuming no overlap, plot 3 (2 white oaks) has a total coverage of 75.7 msq and plot 4 has a total coverage of 80.2 msq. Neither plot has a coverage of 50%, meaning these plots are both fairly open savannas, which is not true given the structure of the trees. It is apparent, however, that canopy coverages vary considerably between plots, despite the appearance of homogeneity to even a trained eye. The most common trees contributing to shade are red oak and white oak but the latter has mostly trees with broader coverage, while the former has many younger trees with smaller coverage. Almost all of the shagbark hickories have smaller crowns (see Table 3 below.)
Table 3: Tree crown cover (msq) | |||||
plot # | species | | | | |
| Car ova | Que ell | Que mac | Que rub | Que alb |
1 | 27.1 | 24.6 | 16.6 | 29.2 | |
323.6 | 14.5 | | | 91.6 | |
129% | 22.1 | | | 21.2 | |
| 6.6 | | | 15.2 | |
| 35.3 | | | 19.6 | |
total | 105.6 | 24.6 | 16.6 | 176.8 | |
| | | | | |
2 | 24.6 | | | 29.2 | 188.7 |
491.4 | 28.3 | 420.2 | | 141 | 18.1 |
196.6% | | 168.1 | | 62.2 | |
total | 52.9 | | | 232.4 | 206.1 |
| | | | | |
3 | | | | | 109.5 |
60.1% | | | | | 41.9 |
total | | | | | 151.4 |
| | | | | |
4 | | | 25.5 | | 25.5 |
385.5 | 320 | | 14.5 | | 88.2 |
154.2% | 128% | | | | 181.5 |
| | | | | 50.3 |
total | | | 40 | | 345.5 |
Table 4 shows the results for the understory – shrubs and saplings for Unit C only. Two shrub species, buckthorn and gray dogwood are not given since their contributions are small and less significant. Most of the oaks are small shrubs barely over 10 cm in height. Recent burning explains this phenomenon. The most abundant shrub by far is red oak with 98 stems. Shagbark hickory has half that many and white oak one third as many. The black oaks may be red since there are no black oaks in the canopy. The invasive black cherry is small but significant since it is a target for removal. Bur oak is absent from the shrub layer.
Table 4: Shrub and sapling stems | ||||||
plot # | species | |||||
| Car ova | Que vel | Que rub | Que mac | Que alb | Pru ser |
1 | 5 | | | | | |
| | | | | | |
2 | 10 | | 14 | 2 | | |
| | | | | | |
3 | 6 | | 12 | | 3 | |
| | | | | | |
4 | 13 | 1 | 22 | | 6 | 6 |
| | | | | | |
5 | 13 | 7 | 18 | | 7 | 8 |
| | | | | | |
6 | 2 | 13 | 32 | | 17 | 9 |
| | | | | | |
total | 49 | 21 | 98 | 2 | 33 | 23 |
Quantitative herbaceous vegetation
In Unit C two 100-meter transects were sampled every 5 meters yielding 20, ¼ msq square plots in each. Both followed a north to south direction, one on the west lobe and one on the east lobe. Sampling took place on September 1, 2016. The results of this sampling are given in Appendices C-1 and C-2, respectively. The data tables are too large to display in the text, so a short summary of those species occurring in 4 or more plots (frequency = or > 20 %) are as follows. A total of 51 different species were found in the west transect, 41 natives and 10 exotics. The mean # native spp/plot was 5.6. The five native species with a minimum frequency greater than or equal to 20% are Hylodesmum glutinosum (15), Carex pensylvanica (14), Amphicarpa bracteata (8), Solidago ulmifolia (7), and Erigeron pulchellus (4). Seven additional native species occurred in 3 plots. Three exotic species reached frequencies of 3 or 4. Of the 41 native species present, 29 (71%) occur in only 1 or 2 plots.
In the east transect (C-2), 29 species were recorded, 27 natives and 2 exotics. The mean # natives/plot 5.25. 8 native species occurred in 4 or more plots, as follows: Hylodesmum glutinosum (19), Carex pensylvanica (13), Solidago ulmifolia (11), Amphicarpaea bracteata (9), Allium cernuum (7),Galium concinnum (4), Vitis riparia (4), and Prunus serotina (4). Six additional native species occurred in 3 plots. The two exotics occurred only once. Of the 27 native species present, 13 (48%) occur in only 1 or 2 plots.
In Unit D, the small size of the target community forced sampling in 3 parallel east-west transects, all considered typical of the same savanna/woodland community. Sampling took place on August 15, 2016. The results of this exercise are again too large for text display and are given in Appendix D. In this 20-plot sample 34 native species were recorded, 32 of which are native. The mean # species per plot was 5.15. Eight native species had a frequency > or = 20%. They include: Carex pensylvanica (11), Amphicarpaea bracteata (10), Hylodesmum glutinosum (10), Helianthus divaricatus (8), Symphyotrichum oolentangiense (7), Allium cernuum (6), Lithospermum canescens (5), and Euphorbia corollata (4). An additional 6 native species occurred in 3 plots. A total of 17 native species out of 32, or 53%, occurred in only 1 or 2 plots. Most notably, the two exotic grasses, Smooth brome and Canada bluegrass, were found in 7 and 3 plots, respectively.
In sampling Unit D, 11 plots were primarily in sunshine and 9 in shade (see Appendix D). Thirteen of the 32 native species are primarily prairie plants. Tables 5 and 6 below give the number of individuals of each of these species in sun and shade.
Table 5: Prairie plant occurrence in shade/sun (13 species)
species | # in sun | # in shade |
Amorpha canescens | 1 | 1 |
Lithospermum canescens | 5 | 0 |
Anemone cylindrica | 0 | 1 |
Sorghastrum nutans | 3 | 0 |
Symphyotrichum oolentangiense | 7 | 0 |
Comandra umbellata | 2 | 1 |
Viola pedata | 3 | 0 |
Schizachyrium scoparium | 5 | 0 |
Dalea purpurea | 1 | 0 |
Bouteloua curtipendula | 2 | 0 |
Allium cernuum | 5 | 1 |
Euphorbia corollata | 4 | 0 |
Antennaria plantaginifolia | 0 | 1 |
Table 6 below gives woodland plant occurrence in sun and shade.
Table 6: Woodland plant occurrence in shade/sun (11species)
species | # in sun | # in shade |
Solidago ulmifolia | 1 | 2 |
Amphicarpaea bracteata | 4 | 6 |
Hylodesmum glutinosum | 3 | 7 |
Carex pensylvanica | 6 | 5 |
Smilacina racemosa | 0 | 1 |
Helianthus divaricatus | 4 | 4 |
Botrychium virginianum | 1 | 2 |
Phryma leptostachya | 1 | 0 |
Aquilegia canadensis | 1 | 0 |
Sanicula odorata | 0 | 1 |
Hepatica americana | 0 | 1 |
Butterfly survey
Rainy weather and abundant mosquitoes limited the butterfly survey to one day, July 2. This is within the peak adult flight period for open woodland and some savanna species. The results are given in Table 7. A total of 38 individuals, and 9 species were discovered in Unit C. The two hairstreaks are woodland and savanna species. The Little wood satyr is a common woodland butterfly, while the Mourning cloak is a wetland and woodland denizen. The remainder are species of grasslands and forest edge habitat.
Table 7: Unit C woodland butterflies | ||||
Date: 7/2/18 | start time: 2;00 pm end time: 4:00 pm | |||
weather: sunny, calm, 84 deg | ||||
species | ||||
Silver spotted skipper | | 1 | | |
Hickory hairstreak | | 3 | | |
Banded hairstreak | | 9 | | |
Spring azure | | 5 | | |
Eastern tailed blue | | 6 | | |
Red admiral | | 1 | | |
Mourning cloak | | 1 | | |
Monarch | | 9 | | |
Little wood satyr | | 3 | | |
Bird survey
The results of the bird surveys for Unit A-B are given in Appendices E-1 and E-2. Those for Unit C are in Appendices E-3 and E-4. Unit A-B had 82 individuals covering 24 species, and 57 individuals covering 22 species on its second run. An additional 8 species were recorded in the wetlands and prairies near the woodlands. Unit C had 74 individuals covering 22 species, and 55 individuals covering 19 species in the second run.
The 4 most common birds in Unit A-B include the Eastern Wood Pee Wee (12), Common Yellowthroat (11), Robin (9), and Red-bellied Woodpecker (6). The 5 most common birds in unit C are the Robin (19), Common Yellowthroat (9), Song sparrow (6), and the Eastern Wood Peewee and Bluejay (6).
Table 8 gives the composition of woodland birds for both survey units and times.
Table 8: Woodland Birds found in Moraine Hills -- occurrences on each of 4 survey dates
survey unit/time | AB-1 | AB-2 | C-1 | C-2 | mean |
species | |||||
*Red-billed woodpecker | 6 | 3 | 2 | 4 | 3.75 |
*Hairy woodpecker | 2 | 1 | 1 | 1 | 1.25 |
*Common flicker | 2 | 1 | 4 | 1.75 | |
*Downy woodpecker | 1 | 1 | 3 | 1.25 | |
*White-breasted nuthatch | 2 | 3 | 2 | 4 | 2.75 |
*Chickadee | 1 | .25 | |||
Eastern wood peewee | 12 | 6 | 5 | 3 | 6.5 |
*Great-crested flycatcher | 2 | 1 | 2 | 1 | 1.5 |
Acadian flycatcher | 1 | .25 | |||
Blue gray gnatcatcher | 2 | .50 | |||
Wood thrush | 1 | 1 | .50 | ||
*Eastern bluebird | 1 | .25 | |||
Scarlet tanager | 2 | 1 | 4 | 2 | 2.25 |
Red-eyed vireo | 4 | 3 | 1 | 2 | 2.50 |
Yellow-throated vireo | 1 | 1 | 1 | .75 | |
Indigo bunting | 1 | .25 | |||
Orchard oriole | 1 | .25 | |||
Rose-breasted grosbeak | 2 | 2 | 1.0 | ||
*Red-headed woodpecker | 2 | .5 | |||
total | 39 | 26 25 | 22 | ||
woodland species -- green shading * cavity nester
savanna species – yellow shading
forest species -- blue shading
Of the 19 species found mostly in timbered communities, 10 are primarily woodland birds, which may also occur in forests, 5 occur mostly in multi-layered deciduous forests, and 4 are most often observed in savannas. Nearly half the birds here are cavity nesters (see Table 8).
The most abundant species by far is the Eastern wood peewee, followed by the Red-bellied woodpecker, and White-breasted nuthatch. All three of these species are characteristic of woodlands.
Two other habitat generalists were relatively common – the ubiquitous Robin and Blue jay. Two common forest edge shrub nesters are the Common yellowthroat and Song sparrow.
Discussion
Community quality evaluations
Evaluating the ecological quality of woodland and savanna communities is confounded by the lack of undisturbed examples of them. With the exception of sand savannas, there are less than 10 acres of grade A or B savanna on fine-textured soils in Illinois (White 1978). In fact, prior to the more recent efforts to update the Illinois Natural Areas Inventory, savannas and woodlands were not distinguished from one another. In White (1978) all timbered tracts with 10% to 80% canopy coverage were considered savannas. Under the updated classification (IDNR 2006) timbered land with canopy coverage between 10% and 50% were labeled savannas, while those with a canopy coverage from 50% to 80% were called woodlands. Furthermore, savannas are characterized by open grown canopy trees, large open areas with sufficient light to support prairie grass domination, scattered shrubs, and frequent hot fires. Woodlands are characterized by more straight-grown trees, smaller openings with no prairie grasses, a significant shrub component, and less frequent, and lower intensity fires. Both communities have an open understory (lack of layering), and oak reproduction as saplings and shrubs. Many of the “oak forests” of today were most likely derived from woodlands following fire suppression and invasion by exotic and native trees and shrubs. The diagram in Figure 3 shows how oak-dominated community structure and composition change with fire frequency and soil moisture.
Based on these descriptions, Units A, B, and C, most closely resemble woodlands and Units D and E most closely resemble savannas. Unit D has a distinct prairie opening (see Figures 6 and 7) and open-grown canopy trees, especially Bur oak. Units A, B, and C have straight-grown trees. By far most of them are White and Red oaks (see Since Unit C has the highest species richness, mean C, and % conservatives and the lowest % exotics, it is the best choice for comparing the 1983 results with those from 2018. Unit D is the best choice for comparing the savannas in 1983 and 2018 based on values for the same 4 parameters.
Figure 3: Structural and compositional changes in wooded communities with changes in fire frequency and intensity
Figure 4: Oak woodland with much oak reproduction in opening in Unit C
Figure 5: Shady oak woodland after fire and brush removal Unit C
Figure 6: Oak savanna prairie opening and savanna foreground in Unit D
Figure 7: Oak savanna with hill prairie and small bur oaks Unit D
One measure of community quality is the grading system developed by White (1978). For any site, each community is evaluated for 4 parameters – composition, structure, processes, and environment. Parameter values – H(high) M(moderate) L(low)
Area C: composition structure processes environment
M H/M H/M H
This combination yields a grade of B/C for unit C in 2016 (IDNR 2006). The positive contributing values are high native species richness, significant number of conservative species, the regularity of the fire regime, and recent massive removal of invasive shrubs. The negative contributions come from the large number of exotic species and native increasers, the homogeneity of the ground layer over much of the unit, and the high canopy tree density.
Applying the same evaluation system to unit D:
Area D: composition structure processes environment
M H M H
This combination also yields a grade of B/C in 2016 (White 2008). The positive contributing values are again high species richness, especially for an area of only 1 acre; extensive recent brush removal around the prairie opening and downslope. Brush clearing has recreated the savanna structure, with open grown oaks and a distinct (perhaps too distinct) shift to savanna ground cover at the drip line of the canopy. The negative contributions to the B/C rating are the reduced but still significant number of exotics and higher than expected cover by alien grasses, specifically Smooth Brome and the bluegrasses. Fire has been less frequent than needed.
The ratings using the INAI methodology appear to contradict those calcluated using the coefficients of conservatism in (Wilhelm and Rericha 2017). The mean C’s, FQI’s, and “# of native species” for Units C and D (see Table 1) are more typical of higher rated, grade B communities. Succession in the absence of fire, past livestock grazing, and logging at Moraine Hills State Park have degraded these communities both compositionally and structurally enough to reduce their INAI grades. In Table 1, the high percentage of exotics and low ” % conservatives” are the causes of the differences. Succession following disturbances has reduced the numbers and population sizes of prairie and savanna/woodland plants that require higher levels of light.
The vast majority of savannas and woodlands in the rest of Illinois (INAI 2011) and neighboring states, such as Wisconsin and Iowa (Wisconsin NAI database 2018 and Iowa Natural Areas Inventory 2018, respectively) have become brushy savannas and woodlands, or forests. Examples of grade B or higher savannas are tiny patches of hill prairie on south- and west-facing slopes surrounded by lightly timbered woods. A few high quality woodlands were identified during the Illinois NAI Update project (IDNR 2018). A handful of intensively managed loess hill prairie/savanna sites occur in central and northeast Illinois (e.g. Shoal Creek Barrens in Montgomery County, several Peoria Park District loess hill prairies) (IDNR 2011) and Bluff Spring Fen in western Cook County). In southern Wisconsin, Genesee Oak Opening SNA in Waukesha Co. is a very high quality savanna (Schennum and Schwaegler 2016) and a model for the restoration of prairie-savanna-woodland ecosystems. Even large sand savannas can be used, especially because they have a large prairie component, very high quality, and several successional phases. Two of the best examples are Illinois Beach St. Pk. in Lake County and Kankakee Sands in eastern Illinois and western Indiana. Moraine Hills St. Pk. and a number of other sites in northeast Illinois are being actively restored and may recover the high richness and open structure they once had.
Quantitative vegetation evaluations
The faunistic and floristic quantitative studies conducted between 2016 and 2018 at Moraine Hills, the results of which are given in Tables 2 through 8, yield a fountain of information on other ecological characteristics of Moraine Hills’ woodlands and savannas and their management needs. Units C and D are again the best examples to examine, although Unit B is a suitable example of woodland similar to Unit C.
Unit C-main (Table 2) has over twice as many white oaks as red oaks in the canopy and subcanopy. However, in the sapling layer in Unit C-main, there are 48 red oaks and only 2 white oaks, no bur or black oaks. Red oak is the most shade tolerant of the 4 oak species present ((Curtis 1959). Table 4 shows a total of 98 small red oak saplings and oak bushes; while white oak has 33. The shade-tolerant hickory has 16 more stems than white oak. Clearly, ecological succession is moving toward a much shadier woodland, or even a forest with much lower species richness. The dominant trees would be red oak and shagbark hickory.
If the data on canopy coverage (Table 3) were more reliable, one could calculate the range and mean for the amount of shaded area in each plot, and then the average amount of shaded ground in the whole woodland, to see if this matches the 50% to 80% level defined by the INAI (2006). According to Table 3, 3 of the 4 plots are far too well shaded to be woodlands. Only plot 3, at 60% shade would be classified as woodland. This is true even if only the largest trees (in yellow in Table 3) are counted. However, simple examination of the photos in Figures 4 and 5 indicates that shade levels vary widely from open areas filled with oak saplings (Figure 4) to heavily shaded groves with little light penetration (Figure 5). The target of management may be to create and maintain this complex system. Logging, especially clear-cutting, leads to regrowth of smaller, denser. even-aged trees. Even progressive removal of older canopy trees over an extended period of time can create this aberrant woodland structure. Management would then seek to thin out the dense groves to create a mosaic of small open areas and semi-open groves with 50% to 80% light penetration.
It is worth noting that in the Government Land Survey notes (McHenry County Planning Dept. 1976) for the area in Unit C the dominant canopy trees were recorded as white oak, black oak, and bur oak with no description of the understory. In 2019, red and white oaks are dominant trees, bur oaks are limited to ridge tops, and one black oak occurs on the woody plant canopy transect. As long as the surveyors’ identifications were correct, red oak has replaced black oak, and black oak was logged out or died out. If true, this indicates a succession to more mesic and forest-like conditions.
Unit D (see Table 2) has 20 individual trees, ¾ of which are
short open-grown bur oaks. Unfortunately no data was recorded for the understory and shrub layers. There are no saplings of any of the canopy oaks, though black and bur oaks are frequent as bushes (Figures 6 and &7). The savanna is circular and so small at .8 acres that only 3 plots were sampled in the canopy layer, with an average of 7.3 trees/plot (see Table 2). As is the case for Unit C, one can assume for Unit D an average radius of 2 meters (area =12.6 msq) for 7.3 trees/plot, then the total coverage per plot is 92 msq, which is 36.8% of the plot. This value falls within the savanna range of 10% to 50% canopy coverage. However, the plots are not identical. The south and west slopes are thinly timbered like savannas while the east “slope” has far more trees and more like a woodland. Management would seek to maintain this difference.
Quantitative herbaceous layer sampling in Units C and D yield some information on the quality and successional state (community types) of these study units. In the Results section for unit C, there are two parallel transects. On the west transect, which has the more open structure, 41 native species were recorded in plots. The four most frequent are typical woodland plants but occur in shaded plots as well as less shaded ones. The latter 3 have C-values of 5. Higher rated species seldom in deeper shade, such as Erigeron pulchellus, Amorpha canescens, Symphyotrichum oolentangiense, and Crocanthemum bicknellii occur in 3 to 4 plots or less. On the east transect, generally more shaded except in one large blow-down area, only 27 native species were recorded. The 4 most frequent are the same as those in the west transect. Higher rated species requiring more light, such as S. oolentangiense, Heuchera richardsonii, and Galium boreale occur in only 1 plot each. Clearly, these data reinforce the conclusion that much of the woodland in Unit C is too dense to have the composition and structure of the community or communities that once existed here.
The quantitative herbaceous data for Unit D, given in Appendix D, recorded 32 native species. These transects did not include plots in the hill prairie. From Table 1, 23 typical prairie plants are found in this entire .8-acre savanna, 13 of which occur in the transect plots. During the sampling, each quadrat was described as occurring in shade or sun (see Tables 5 and 6 in the Results). Table 5 gives the distribution of prairie plants on the transect, while Table 6 does the same for woodland plants. Only 2 of the 13 prairie plants are more frequent in the shade, and only 4 are recorded for shaded quadrats, as one individual each. In contrast, only 3 woodland plants are restricted to shaded plots. Seven of the woodland plants are more frequent, including the 3 just mentioned, in shaded quadrats. Eight of the 11 woodland species do occur in sunny plots, a few in relatively high frequencies. All this data prove that the small hill prairie is very diverse, but is the only area capable of supporting a prairie flora. The savanna’s openings or areas of filtered light are too small and would need to be enlarged to allow prairie to colonize them. Brush clearing was done, especially on the south and west slopes in 2017-2018. The response should be monitored for several years. Brush removal on the east and north side should provide sufficient light to support a more diverse and higher quality savanna/woodland there than that which currently exists.
Butterfly survey evaluation
The 2018 butterfly survey was so limited in time and space that it probably does not adequately assess the habitat value of the Moraine Hills St. Pk. woodlands. Limited to Unit C’s main section, it at least covered the largest and floristically richest woodland in the park. Four of the butterflies recorded are woodland species – Banded hairstreak (Figure 8), Hickory hairstreak, Mourning cloak, (Figure 9) and Little wood satyr. (Bouseman and Sternburg 2006, and Bouseman et al 2001). Only the Hickory hairstreak is considered remnant-dependent (Panzer et al 2010) A butterfly survey conducted in Unit C in 1999 (Schennum 1999) found 20 species 9 of which are characteristic woodland and savanna butterflies. None of these are remnant-dependent. Based on larval host plants which occur in Units C and/or D at a relative abundance of 3 or higher, the following savanna and woodland species may occur here: Hobomok skipper, Northern broken dash, *Sleepy dusky wing, Juvenal’s dusky wing, Horace’s dusky wing, *Mottled dusky wing, *Columbine dusky wing, *Southern and *Northern cloudy wing, Striped and *Edward’s Hairstreak, *Silvery Blue, American painted lady, snd Great spangled fritillary. The species with an * are listed as remnant-dependent by Panzer et al (2010). A more comprehensive survey is needed if any of these species are to be found, as well as more common ones. It is likely that the low light levels are responsible for the absence of many of these butterflies as well as their small populations. The management undertaken should increase species richness and total numbers. Another potential cause is the increased use of the non-specific neonicitinoid insecticides (Volk 2017),
Bird survey evaluation
I know of no recent formal bird surveys of the woodlands at MHSP.
Therefore there is no way to check changes over the 35 years of management. However, an analysis of the guilds and individual species presence or absence is possible. This analysis applies to Unit A & B (combined) and Unit C. In this regard, some comparisons can be made with Deer Grove, a 1000-acre mixture of woodlands, forests, and wetlands that have been managed for 22 years, since a comprehensive study was conducted by Schennum et al.(1996). Knowledgeable volunteer birders have been observing and recording Deer Groves avifauna during those 22 years.
Combining the results from surveys A-B and C, the total number of savanna, shrub, woodland, and forest birds is 32. Because of the proximity of the woodlands to large wetlands and prairie restorations, 9 wetland and 2 grassland birds were also observed, including Sandhill Cranes and Bobolinks. The total is then 43. Table 6 contains occurrence data on the species considered breeding woodland birds in the 2018 survey of Units A, B, and C. Habitat associations are derived from DeVore et al (2004) and (Ehrlich et al 1988) Four savanna birds were recorded, and with the exception of the Common flicker, all are very rare in the woodlands. Two savanna/open woodland species not observed include the Northern Oriole and Rufous-sided Towhee. The latter is found in timbered areas with a significant shrub layer. Five forest species were observed during the survey, but only 2, the Red-eyed vireo and Scarlet Tanager occurred in relatively high numbers. In contrast, there are 10 woodland birds nesting in the survey units (examples in Figures 10 and 11. Three of them are in very low numbers. A number of forest birds also occur in woodlands, such as the Red-eyed and Yellow-throated vireos. At Deer Grove, 35 woodland birds were observed in 1996 (Schennum et al.1996)I believe the difference is not due to habitat quality but to size and shape. The total survey area at Moraine Hills is 50 acres, compared to as much as 900 wooded acres at Deer Grove. Habitat fragmentation by wetlands has created an edge effect which reduces the space available for woodland birds. Some management changes should increase MHP’s bird species richness and population sizes.
Figure 8: Banded hairstreak
Figure 9: Mourning cloak
Figure 10: Red-bellied woodpecker
Figure 11: Great-crested flycatcher
Vegetation changes since 1983
The original vegetation studies in 1983 (Schennum 1983) were conducted prior to any known management of the wooded communities. At that time, plant species lists with estimated relative abundances were conducted in all of the 5 wooded units; quantitative sampling of the woody vegetation was taken on the canopy and all trees exceeding 10 cm dbh for all units; and transect sampling of the herbaceous vegetation was conducted in Units C and D. The methods for quantitative sampling differed from those described earlier for 2016 – 2018. Tree sampling used the prism method wherein all trees whose diameters exceeded that of a penny held at arm’s length from a fixed point were measured. This method is biased in favor of large trees and trees close to the investigator. Herbaceous vegetation sampling used 1 msq, not ¼ msq, as its plot size. This method is biased in favor of the more common species. As a result, comparisons between 1983 and 2018 are somewhat limited. Species lists for Units A, B, C, and D can be compared. Quantitative herbaceous data can becompared for Units C and D, though cautiously. Quantitative canopy data can be compared with reservations for Units A, B, C, and D. Unit E was dropped in 2019 because of its poor quality, so it is eliminated here.
The comparison of 1983 data to that for 2018 for Unit A is in Appendix F1; it is too large to insert into the text. For all herbaceous species listed comparisons of the following figures are presented: species occurring in both years and their relative abundances; mean C values for each species; changes in relative abundances and presence/absence interpretation. Color highlighting is used for clarity. New species found in 2018 are also presented. Summaries are provided for Unit A in Table 9 which follows.
Table 9: Unit A Comparison, 1983 with 2018
year | 1983 | 2018 |
variable compared | ||
total # species | 127 | 100 |
# native species | 97 | 77 |
# exotic species | 30 | 23 |
% exotic species | 23.6% | 23% |
mean C | 4.216 | 4.403 |
FQI | 41.522 | 38.636 |
# conservative species | 20 | 17 |
% conservative species | 20.6% | 23.4% |
# declining species | 31 | <31 |
# increasing species | 11 | 11> |
# species w/ no change | 20 | --- |
The most obvious change in Unit A over 35 years is the decrease in total species and native species richness. Unit A has not received as much management attention as the other units, and this is the probable cause for the declines in these factors, as well as the modest increases in the mean C and percent conservatives. Prescribed burning has been sporadic here, and very little brush removal has occurred. However, 15 exotic species have disappeared, and 6 more have decreased in abundance. Most importantly, a few of the exotics that have behaved in this manner are major competitors with native grasses -- both bluegrasses – or are difficult to eradicate – Deadly nightshade and Yellow sweet clover. The modest increases in the mean C and % conservatives are likely due to continued low light levels caused by dense colonies of Gray dogwood and both exotic honeysuckles (now more common), and Autumn Olive (not present in 1983). Another alien invader since 1983 is Garlic Mustard, but its numbers are very low, for now. It should be removed and monitored soon.
Notable prairie and savanna/woodland species first recorded in 2016 – 2018 are 3 woodland grasses (and Wood rush), which are now creating a better fuel load along with Common oak sedge. Such forbs as Purple milkweed, Northern bedstraw, Michigan lily, and Starry false Solomon’s seal, along with the grasses and sedges, are good signs of recovery. However, several conservative indicators have declined or disappeared since 1983, including Large yellow false foxglove (decline) (Figure 13), White wild indigo, New Jersey tea (decline) (Figure 14), Hazelnut, Robin’s plantain (Figure 15), Woodland sunflower, Alum root, Starry campion. and Blue-eyed grass – 9 very significant indicator species in all. All these plants are partially shade tolerant and often found in other savanna and woodland tracts in the Chicago Region that are being managed to recover these two communities. Some of them may persist in the seed or rootling bank. Complete clearing of exotic brush, especially Autumn olive and the 2 honeysuckles, in combination with prescribed burning annually or biennially will determine if they remain or require reintroduction.
The comparisons of vegetation changes between 1983 and 2018 for Unit B are given in Appendix F2. The summary is presented in Table 10 below.
Table 10: Unit B Comparison, 1983 with 2018
year | 1983 | 2018 |
variable compared | ||
total # species | 139 | 127 |
# native species | 102 | 95 |
# exotic species | 37 | 32 |
% exotic species | 25.9% | 25.2% |
mean C | 4.569 | 4.815 |
FQI | 46.145 | 46.931 |
# conservative species | 27 | 24 |
% conservative species | 26.5% | 25.3% |
# declining species | <35 | < 35 |
# increasing species | >20 | > 20 |
# species w/ no change | 24 | --- |
Unit B, like Unit A, shows a modest decrease in the total number of species and native species over the 35-year period. Prior to the winter of 2017-2018, there had been little to no brush removal. The burning history of this unit is not well known, but at least some prescribed fires were conducted. The slightly higher mean C and lower % conservatives seem contradictory. The ambiguity may be due to heavier past grazing. Certainly Unit B was more open than the other western units, as shown in the 1939 aerial photo of the park (see Figure 12). If so, Unit B was more savanna-like and was more prone to degradation by livestock grazing and shading than the other units. There is almost no change in % exotics between 1983 an 2018, again indicating less management and a more disturbed system. Nevertheless, 15 exotics have disappeared and 9 have decreased, a definite indication of improvement. The need for more intensive management work is indicated by the appearance and high frequency of Garlic Mustard and the recent invasion by Oriental Bittersweet, two exotics that have been proven to displace or shade out native herbaceous species.
A number of prairie and savanna/woodland indicator plants were recorded in Unit B for the first time. As in Unit A, the three major woodland grasses -- Silky wild rye, Woodland fesque, and Bottlebrush grass --are now frequent, yet were never seen in 1983. They combine with Common oak sedge to form at least partially continuous ground cover. They and the following indicator species typical of sunlit openings are an indication of recovery – Poke milkweed, Rockrose frostweed (Figure 17), Wood rush, Wood sandwort, and Culver’s root. However, a suite of conservative indicators have declined or disappeared, including Lead plant, Purple milkweed (Figure 17a), Michigan lily, Starry campion, Sky blue aster, Wood vetch (Figure 16), and Bird’s foot violet. Infrequent in 1983, Little bluestem grass, was not relocated. These plants are typical prairie and savanna species, probably reduced or eliminated by brush encroachment. Prior to the winter clearing in 2017-2018, invasive brush and trees were denser than in any other unit. These species should return from the seedbank and surviving rootlings after several fires now that the understory has been removed.
Figure 17a: Purple milkweed
Figure 12: 1939 aerial photo of Moraine Hills St. Pk. Region
Figure 13: Yellow false foxglove
Figure 14: New Jersey tea
Figure 15: Robin’s plantain
Figure 16: Wood vetch
Figure 17: Rockrose frostweed
Unit C is the most complex area of all studied. It has been the most intensively managed, having been burned (twice) and cleared of invasive brush from 2016 to 2018. Both volunteers and IDNR staff teams were involved in these activities. Referring to Table I, it has been inventoried for plants as a whole unit; one subunit, the “island”, was also inventoried separately (see Table 1). However, since most of the island was not studied in 1983, a comparison between 1983 and 2018 cannot be made. Any species observed on the island, but not seen elsewhere in Unit C, was added to the larger unit evaluation. The full complement of data for Unit C is in Appendix F3.
Table 11 below is a summary comparison between 1983 and 2018 for Unit C.
Table 11: Unit C Comparison, 1983 with 2018
year | 1983 | 2018 |
variable compared | ||
total # species | 149 | 162 |
# native species | 119 | 127 |
# exotic species | 30 | 35 |
% exotic species | 25.2 | 21.6 |
mean C | 4.975 | 5.157 |
FQI | 54.269 | 58.122 |
# conservative species | 39 | 45 |
% conservative species | 32.8% | 35.4% |
# declining species | <29 | |
# increasing species | >37 | |
# species w/ no change | 37 |
Unit C is the largest of the units studied at 25 acres. It also has a number of dry knolls and exposed slopes that increase community diversity. (The 1939 aerial photo shows both savanna and woodland tree cover). Because Unit C is mostly internal and bounded by a matrix of wetlands, it may have been grazed less by livestock. Unit C has also received the most management attention, by both volunteers and IDNR staff. The volunteer work enlarged several once smaller and more shaded openings in a successful effort to increase the amount of sunlit area. Two fairly complete burns have been conducted here in the last 3 years. Table 11 indicates that all of the metrics used to determine quality have increased, except for the number of exotics (and the % exotics dropped anyway). Some of these increases are small, but very significant given that all of them increase together. Three new problem exotics – Garlic Mustard, Climbing Bittersweet, Autumn Olive – were first recorded in the 2016-2018 survey. Most of the Autumn Olive has been cut and herbicided.
Several new conservative and indicator species of savannas and woodlands were observed for the first time in Unit C, including Broad-leaved panic grass, Northern bedstraw, Canada hawkweed, Michigan lily, Wood rush, Prairie cinquefoil, Violet wood sorrel (Figure 19), Seneca snakeroot (Figure 18). All three woodland grasses again appeared for the first time creating a more complete ground cover and better fuel for burns. Equally important was the increase in relative abundance for prairie and savanna-woodland species present in 1983. These include Nodding wild onion, Lead plant (Figure 21), Rue anemone, Large yellow false foxglove, Rockrose frostweed, Shooting star, Alum root, False dandelion, the state threatened Pale vetchling (Figure 22), Wood sandwort (Figure 23), Starry campion, Blue-eyed grass, Sky blue aster, Wood vetch, and Bird’s foot violet. Only 3 indicator species decreased or were not relocated, and they may yet be rediscovered. Clearly, management, especially the most recent efforts, have produced significant increases in the unit’s richness and diversity.
Unit D could have a number of designations. The prairie in the center is a true prairie, dominated by prairie grasses, especially Little bluestem and Side oats gramma. These form the matrix for dry prairies (White 1978). Because it is surrounded by trees and on the top and slopes of a glacial kame, it is called a hill prairie (White 1978). Most of the mature oaks and oak bushes are Bur and Black oak. The savanna refers to the lightly timbered area surrounding the prairie, though the trees may be dense enough to call it woodland, and it is dominated by Common oak sedge. For the purposes of this study the combination of the two is a savanna.
Figure 18: Senega snakeroot
Figure 19: Violet wood sorrel
Figure 22: Pale vetchling (threatened in Illinois)
Figure 21: Lead plant
Figure 23: Wood sandwort
Table 10 below is a summary comparison between 1983 and 2018 for Unit D. The entire analysis is very long and is displayed in Appendix F4.
Table 12: Comparison of 1983 and 2018 for Unit D.
year | 1983 | 2018 |
variable compared | ||
total # species | 105 | 114 |
# native species | 88 | 93 |
# exotic species | 17 | 21 |
% exotic species | 16.2 | 18.4% |
mean C | 4.966 | 4.989 |
FQI | 46.584 | 48.112 |
# conservative species | 26 | 31 |
% conservative species | 29.5% | 30.1% |
# declining species | <21 | |
# increasing species | >16 | |
# species w/ no change | 26 |
Unit D is the smallest area studied at about 1 acre. Despite its size it has 88 species of native plants. Most of the invasive brush on the wooded slopes below the prairie has been cleared by volunteers. However, prescribed burning here, at least over the past 10 years, has been sporadic. This has led to a decrease in prairie grass cover and the invasion of Eurasian grasses, including Smooth Brome and both bluegrasses. Prairie grasses are very intolerant of shade, so even branch growth by the bordering oaks is a threat. Even though the exotic species component of the savanna has increased, Table 11 shows all other metrics slightly increasing since 1983. Unit D is the only one in which the number of species unchanged in abundance is higher than those declining or increasing. The stability of this savanna is unexpected, given its management history. The droughthy conditions created by a gravelly substrate and steep south- and west-facing slopes likely account for this.
A modest increase in conservative indicator plants has occurred since 1983. New ones include Broad-leaved panic grass, Poke milkweed, Northern bedstraw, Small skullcap, and Blue-eyed grass. Some species present in 1983 are now more abundant, including Lead plant, False toadflax, Pale vetchling, Hoary puccoon (Figure 24) and Prairie violet. Others have declined, including Purple milkweed, Shooting star (Figure 25), Sky blue aster, Wood vetch, and Bird’s foot violet. Most notably, New Jersey tea, frequent in 1983, is now absent. Two woodland grasses which appeared first in 2018 in other units have not done so here. The loss of New Jersey tea may be due to deer browsing of this very palatable plant (deer browsing was documented with an exclosure in Unit C). Insufficient burning and lack of brush removal in the past is a likely cause of prairie and savanna species declines or absences. A deer hunting program first implemented in the late 1990’s and the more frequent fire should lead to both recovery in prairie/savanna plant abundance and the movement of these species into the wooded areas around the hill prairie.
Figure 24: Hoary puccoon
Figure 25: Shooting star
Management recommendations
The following outcomes from this report determine the management plan objectives needed to make the Moraine Hills wooded uplands studied here the best possible replica of the savanna/woodland ecosystem that once occupied the site.
· The flora of Moraine Hills St. Pk.’s wooded uplands is similar to that noted in several other woodland and savanna restorations in southeastern Wisconsin and northern Illinois.
· This flora contains several species characteristic of upland prairies in this region. Examples are Lead Plant, Shooting Star, Hoary Puccoon, Little blue stem, and Sky blue aster. These species are infrequent and localized in areas receiving the most sunlight. Many other prairie species, especially those blooming in summer and fall, are absent.
· Characteristic spring wildflowers of forests are uncommon; ephemerals are absent.
· There is a large suite of conservative plants that are most often found in partially shaded areas and are virtually absent from most oak-dominated woods today. Examples are Yellow false foxglove, New Jersey tea, Rockrose frostweed, Robin’s plantain, False dandelion, Pale vetchling, Starry campion, and Wood vetch.
· The diversity and population size of exotic herbaceous plants is much higher than expected.
· The dominant trees are Red and White oak, except on dry ridge tops and on the kame in Unit D.
· Except for Red oak, sapling and pole-sized canopy trees are absent; red and white oak bushes are frequent to common.
· Canopy trees are primarily even-aged, straight grown, and without evidence old lower branches.
· The canopy is not closed but still so dense that light penetration is low to moderate; much of the herbaceous layer is homogeneous, not rich or diverse, and dominated by Common oak sedge, Wild geranium, Pointed tick trefoil, and Elm-leaved goldenrod.
· The understory was mainly composed of exotic and invasive native species until volunteers and staff completely removed it in the last three years; hazelnut, the most common shrub documented my the 1830’s land surveyors, exists as only a few individual plants.
· Large old open-grown trees are virtually absent.
· The recent prescribed burns have increased the numbers of blooming plants, including conservative species with low shade tolerance.
· Red oak has replaced Black oak as the co-dominant canopy tree in most of Unit C.
· The most common nesting birds are typical of semi-closed woodlands; several are cavity nesters.
· Forest interior and savanna birds are uncommon; examples of the latter are Bluebirds and Red-headed woodpeckers.
· With the exception of mosquitoes, insects are low in number; the abundance and richness of savanna and woodland butterflies is low; the only species from this guild are two woodland hairstreaks and one satyrid; both are unexpectedly rare.
The principal goal of future management and restoration is to increase the quality and extent of the woodland and savanna communities by increasing the amount of light reaching the herbaceous layer. Here are some suggestions for doing so:
1. Increase the frequency of burning by dividing Unit C into 3 burn units, and conducting spring or fall burns on each unit once every 3 years. Unit D can be burned as one unit, also once every 3 years.
2. The exotic and invasive native brush and small trees cut in Units B and C by the IDNR crew in 2017-2018 were not treated with Garlon 4 herbicide and has now resprouted; some follow-up herbicide treatment was done by Red Buffalo staff from Richmond, IL. Assuming this crew did not finish Units B and the western portion of Unit C, use Red Buffalo and IDNR staff and licensed volunteers to finish this phase of the work.
3. Burn Unit B in its entirety on a two-year rotational cycle.
4. Monitor and herbicide Garlic mustard (Alliaria petiolata) and Oriental bittersweet (Celastrus orbiculatus) annually.
5. Removing invasive brush will not increase light penetration sufficiently to enable plants requiring more light to grow and spread; nor will brush control alone increase White oak reproduction. Canopy coverage is often higher than 80% because the red and white oaks are too close together. Therefore canopy thinning in Unit C is necessary, despite the potential for backlash from park users. Red oaks and White oaks could be girdled by 30% to 50%, respectively, over a 10-year period. Monitoring the impacts of canopy thinning on the herbaceous flora and associated wildlife should be conducted bienially, along with measurement of incident light with a photometer. Canopy tree thinning can be adjusted based on a comparison of light frequency and woodland plant frequency, density, and diversity to the expected values. The canopy trees cut should be left standing as snags for cavity nesting birds and not treated with herbicide. Oaks will resprout from the tree bases to create additional low level understory as oak bushes. This is a desired outcome in savanna and woodland restoration and creates habitat for savanna butterflies and ground nesting birds.
6. Bur oak dominated knolls should, like Unit D, be restored to savannas. The scattered occurrence of prairie plants in the woodlands indicates that savannas were once more prevalent anyway.
7. The highly colonial occurrences of a number of conservative woodland species, even though suitable ecological conditions occur elsewhere on the site, justifies collecting seed from these species and sowing it in those suitable areas where they are currently absent. This will decrease recovery time.
8. Savannas and woodlands had native shrubs that are absent in Moraine Hills (Chicago Wilderness 1999). They include Hazelnut, Wild plum, viburnums, Prairie willow, etc. Seeds, fruits, and/or seedlings of these species could be planted in both savannas and woodlands in Units A, B, and C. The only current shrubs are oak bushes. Hazelnut and oak bushes are frequently described in the GLO notes (McHenry County Planning 1976).
9. Black oak was once a significant component of the Moraine Hills woodlands and savannas. It is still well represented in the canopy and low shrub layer of Unit D. Using the latter as a source of acorns, Black oaks should be planted in the larger spaces left after Red oaks are girdled.
10. Other savannas and woodlands being restored in northeast Illinois have a number of species not found in Moraine Hills. Examples are Wild Hyacinth (Camassia sciloides), Yellow pimpernel (Taenidia integerrima), Violet bush clover (Lespedeza violacea), Veiny pea (Lathyrus venosus), and Bracted tick trefoil (Desmodium cuspidatum). These species can be considered for introduction at Moraine Hills if it provides similar ecological characteristic as the donor site.
11. Five species currently known from Moraine Hills St. Pk. are on the Chicago Wilderness Plants of Concern list – Poke milkeweed (Asclelpias exaltata), Pale vetchlilng, Wood’s stiff sedge (Carex woodii, Round-lobed hepatica (Hepatica americana), and Indian pipe (Monotropa uniflora). To date only Pale vetchling has been monitored (in 2017). The others could be monitored, but a volunteer needs to be found for this task.
12. Currently there are no trails that loop through Unit C to provide access and interpretation of the restoration work. One could be routed through the site as a narrow footpath without damaging the vegetation or harassing wildlife.
Conclusion
Based on the evidence presented here, spanning 35 years of observation, the woodlands/savannas at Moraine Hills St. Pk. form an upland community with the potential of being one that closely resembles that prior to human use. Without continued aggressive management, it will deteriorate into a forest with minimal diversity. The product of all this work can never be an exact replica of the original natural ecosystem, nor should that be the project’s goal. The hypothetical schematic diagram in Figure 3 is based on deductions from current observations of communities that meet a set of compositional and structural conditions that are intermediate between prairie and forest. The product of restoration will in many ways define what woodlands and savannas are at this location. The only intact models we have are minimally disturbed dune-and-swale ecosystems in places like Illinois Beach St. Pk. and Kankakee Sands. These sites have edaphic conditions that resemble Moraine Hills. Other clues come from numerous ongoing restorations, such as Genesee Oak Opening and Whitewater Oak Opening in southern Wisconsin and Deer Grove, Reed-Turner Woodland, and the North Branch Prairie Project in northeastern Illinois. Information shared among ecological restorationists in the region will help recreate the “missing links” that woodlands and savannas represent in the long chain of communities that made up the original Midwest.
Acknowledgements
Many people and organizations have contributed to the study of Moraine Hills State Park’s woodlands and savannas. The following volunteer field biologists used their expertise in the collection and interpretation of the numerous surveys: the Moraine Hills volunteer management crew, Ed Collins, Carolyn Fields, Pete Jackson, Ray Kath, Shelley Kiefer, Gill Moreland, Sarah Schultz, and Heidi Tarasiuk. The agencies and staffs of the Illinois Department of Conservation and Illinois Nature Preserves Commission encouraged and supported the project in many ways; they include Steve Byers, Stacy Iwanicki, Greg Kelly, John Laskowski, Kelly Neal, and Brad Semel.
References
Bouseman, John K., James G. Sternburg, and James R. Wiker. 2006.
Field Guide to the Skipper Butterflies of Illinois. Illinois Natural
History Survey Manual 11, Champaign, IL.
Bouseman, John K. and James G. Sternburg. 2001. Field Guide to
the Butterflies of Illinois. Illinois Natural History Survey Manual 9,
Champaign, IL.
Chicago Wilderness Council. 1999, Chicago Wilderness Biodiversity
Recovery Plan. Chicago Wilderness Biodiversity Council, Chicago,
IL.
Curtis, John. 1959. The Vegetation of Wisconsin: An Ordination of
Plant Communities. The University of Wisconsin Press, Madison,
WI.
DeVore, Sheryl, Steven D. Baily, and Gregory Kennedy. 2004. Birds
of Illinois. Lone Pine International, Inc. Ottawa, Canada.
Ehrlich, Paul, David S. Dobkin, and Darryl Wheye. 1988. The
Birder’s Handbook: A Field Guide to the Natural History of North
American Birds. Simon and Schuster, Inc., Oxford University Press,
New York, NY.
Illinois Department of Natural Resources. 2018. Illinois Natural
Heritage Database. Illinois Division of Natural Heritage, Sprinfield,
IL.
Illinois Departmente of Natural Resources. 2011. Final report of the
Illinois Natural Areas Inventory, 2008-2012. Illinois DNR,
Springfield, IL.
Illinois Department of Natural Resources. 2006. The standards and
guidelines for the Illinois Natural Areas Inventory. IDNR Division
of Natural Heritage, Springfield, IL.
Iowa Department of Natural Resources. 2018. Des Moines, Iowa,
DNR. http//programs:iowadnr.gov/natural areas inventory/pages/
login.aspx.
McFall, Don and Jean Karnes. 1995. A Directory of Illinois Nature
Preserves. Volume 1, Northeastern Illinois. Illinois Department of
Natural Resources, Springfield, IL
McHenry County Planning Department. 1976. Government Field
Notes, 1832-1838. McHenry County Government Center,
Woodstock, IL
Panzer, Ron, Karl Gnaedinger, and George Derkovitz. 2010. The
prevalence and status of conservative prairie and savanna insects
in the Chicago Region. Natural Areas Journal Vol. 1, pp 73-81.
Schennum, Wayne E. and Dave Schwaegler. 2016. Vegetation
study if Genesee Oak Opening SNA, WI. Unpublished data.
Schennum, Wayne E. 1999. Butterflies of Moraine Hills State
Park natural areas. Report to the Illinois Department of Natural
Resources.
Schennum, Wayne, Ed Collins, and Brad Woodson. 1996.
Ecological evaluation of Deer Grove Forest Preserve. Report
to the Cook County Forest Preserve District.
Schennum, Wayne E. 1983. Moraine Hills State Park, McHenry
County. An ecological analysis of selected timbered areas with
recommendations for management. Report to the Illnois
Department of Natural Resources.
Schwegman, J.E., G,B. Fell, M. Hutchison, G. Paulson, W.M.
Shepherd, and J.W. White. 1973. Comprehensive plan for the
Illinois Nature Preserves System. Part 2—the Natural Divisions
of Illinois. Illinois Nature Preserves Commission, Rockford.
32 pp + map.
Stevens, William K. 1995. Miracle Under the Oaks—the Revival
of Nature in America. Pocket Books, New York, NY.
United States Department of Agriculture. 2017. websoilsurvey.
nrcs.usda.gov.
Volk, Steve. 2017. Buzzkill. Discover 38(2). pp 30-37.
White, John. 1978. Illinois Natural Inventory Technical Report:
Methods and Preliminary Results. The Natural Land Institute,
Rockford, IL.
Wilhelm, Gerould and Laura Rericha. 2017. Flora of the Chicago
Region: Indiana Academy of Science, Indianapolis, IN.
Willman, H.B. 1971. Summary of the Geology of the Chicago Area.
Circular 460. Illinois State Geological Survey, Urbana, IL.
Wisconsin Department of Natural Resources. 2016.
nr.wi.gov/topic/nhl/^
EARTH
The only known planet in the universe to support life.
-----------------------------------------------------------------------------------------------------------
Comments on Dr. Shennum's draft:
This recently discovered draft was unfinished at the time of Dr. Schennum's death. It is now being used (by IDNR staff and volunteer stewards of Friends of Illinois Nature Preserves) to inform restoration and management of the site.
Dr. Schennum died on August 16, 2021 while working alone in this preserve, most likely doing stewardship or completing this study. The decision to share his impressive work in this form was made by his wife and colleagues.
Maps have been removed from this this draft as it was thought that they would provide too detailed locations for the site's Endangered and Treatened species and possibly result in too much trampling of especially sensitive areas.
Dr. Shennum gave a list of Appendices (shown below), but to date they have not been located:
List of Appendices
Appendix A: 1 through 6; 2016-2018 plant surveys
Appendix B: 1 through 7; Quantitative canopy data
Appendix C: Herbaceous vegetation data Unit C (1983 vs 2018)
Appendix D: Herbaceous data for Unit D (1983 vs 2018)
Appendix E: 1 and 2: Bird Survey for Unit A – B
3 and 4: Bird Survey for Unit C
Appendix F: 1 through 4; Comparison of 1983 plant inventory
results with 2018 plant inventory results
No comments:
Post a Comment