Inquiry Into the Nature of Riveredge Nature Center
A Report on Research Activities, 1970-2000
This report describes the research activities at Riveredge Nature Center undertaken since 1970. These activities are or were undertaken primarily to provide information on the Riveredge Nature Center land and those who inhabit it such that informed decisions are made regarding the stewardship of the sanctuary. Some of the inventory activities also contribute to state or national inventory efforts.
Volunteers, who receive training from the Center’s staff, conduct many of the data collecting activities.
Index: Ongoing Studies
- A Study of the Relationships Between Prairie Plants and Invertebrates – B.Greenler, et al.
- Breeding Bird Survey of RNC Creek - S. Kupcho, et al.
- MAPS Bird Banding at RNC – A. Sherkow and D. Hartmann, et al.
- Butterfly Count – A. Larsen
- Evaluation of the Engineered Wetland Wastewater Treatment System at RNC - D. Flowers
- Maple Syrup Production in the RNC Sugarbush – D. Gilmore
- Breeding Frog and Toad Survey - RNC Staff, et al.
- Gypsy Moth Monitoring at RNC – USDA and M. Holleback
- RNC Christmas Bird Count - M. Holleback and A.Larsen
- Relationship between Maximum & Minimum Temperatures and Sap Flow in the RNC Sugarbush – D. Gilmore
- Swamp Metalmark Reintroduction Project – S.Borkin, MPM
- Vegetation Survey of RNC – A. Larsen, L. Olsen, L. Zimmerman, et al.
- The Effect of Four Different Treatments of Litter on the Prairie – A. Larsen, et al.
Index: Completed Studies
- 14. A 12-year Study of Road Killed Animals Along an 11-mile Stretch of Ozaukee County Highway – A. Larsen
- A Simplified RNC Soils Map – F. Hole
- A Study of the Vernal Pond at RNC – P. Rossa
- Bird Banding of Resident and Migratory Birds at RNC – A. Larsen
- Bluegill Population Survey of RNC Farm Pond – A. Larsen
- Chickadee Populations and Longevity – A. Larsen
- Collection of Some Fishes of the Milwaukee River – B. Esselman and T. Onash
- Deer Tick Survey at RNC – U. of Illinois Medical College
- Earthworm Activity at RNC – H. Borg
- Dragonfly Survey – A. Larsen, S. Putz and P. McKenzie
- Factors Affecting the Germination of Prairie Seed – A. Heon, and A. Larsen
- Fishes of the Milwaukee River at RNC – WDNR
- Factors Affecting Maple Sap Production in the RNC Sugarbush – H. Teselle
- History of Select Forest Stands at RNC as Determined by Dendrochronology – A. Larsen, et al.
- Improving Blue Bird Nest Box Production – M. Holleback
- May Day Bird Survey – N. Cutright, et al.
- Nitrate Levels in RNC Creek – J. Goham
- Notes on the Millipede, Pleuroloma flavipes, in Wisconsin – D. Watermolen
- A Phenologic Record of Natural Events 1969-2000 – A. Larsen
- The Small Mammals of RNC – C. Farrell
- Stump Study of RNC Forest – T. Grossman
- Status of the Cooper’s Hawk in Wisconsin – R. Rosenfield, UW-Stevens Point and WDNR
- Soil Phosphate Distribution – H. Purtell
- Sugarbush Insect and Disease Survey – M. Drilias, WDNR
- The Effect of Soil Denitrification on Establishment of Prairie Plants – A. Larsen, C. Kenney, et al.
The following are University Wisconsin-Milwaukee
completed Master’s thesis:
39. Swartz, B.P. 1977. A management plan for a swamp forest based on vegetation analysis. M.S. Thesis. University Wisconsin-Milwlaukee.83p.
40. Paul, R.K. 1970. A geological resource guide to the RNC, Ozaukee County, WI. M.S. Thesis. University Wisconsin-Milwaukee. 84p.
41. Purtell, H.M. 1984. Factorial ecology of the vegetation and soils in a disturbed
riverside oak-maple woodland in southeastern Wisconsin. M.S. Thesis. University Wisconsin-Milwaukee.186p.
Ongoing Studies and Research
A Study of the Relationships Between Prairie Plants and Invertebrates.
B. Greenler, et al.
Observations of prairie plants begin in early spring and continue into November. The activity of the invertebrate on the plant is recorded, and a specimen is collected for identification and inclusion in a collection.
To date, 1,061 observations of invertebrate activity on prairie plants have been documented. One state range record of a leafhopper has been established, and many species not previously known at RNC have been encountered. However, much of the collection has not been classified to species and awaits that effort.
Initial analysis of the data substantiates the preference of certain plants by invertebrates. Stiff Goldenrod was the most frequently used plant species on the prairie and insect visitors were evenly distributed among the orders.
There appear to be some plant species that offer similar resources to invertebrates. These plants may be viewed as a guild. The two Silphiums share a lack of visitation by any Lepidoptera, but are favorites of the Homopterans. Spiderwort, Lead Plant and Lupine were not visited by Homopterans. Similarly, the contrast between the Pale Purple Coneflower and Purple Coneflower in the occurrence of Coleopteran beetles and Hemipteran bugs suggests that these species are considerably different in the resources that they offer to visitors. The lack of Orthoperans on T. ohioensis and A. patens may be attributed to the temporal occurrence of grasshoppers. Another guild characteristic is seen in R. pinnata and P. purpureum in which Coleoptera and Hemiptera are high but Diptera flies are equal to or less than 10%.
This study is expansive and there exists much more to be done with this ongoing study. Field collecting needs to continue concurrent with incorporation of new information into the database and analysis of new data. Identification of specimens to species continues to be a frustration, with less than 10% of the specimens classified to species. None-the-less new insights into the nature of the prairie including the plants and invertebrates that comprise it, continue.
Breeding Bird Survey Of RNC Creek
S. Kupcho, et al.
Surveys of the RNC State Natural Area (#197) began in 1987. The number of species encountered has ranged from a low of 37 species (1995) to a high of 46 species (1991, 1992). The number of individuals has between 195 and 360. The most common species encountered among the 73 species identified during the survey include the Song Sparrow, House Wren, Gray Catbird, Northern Cardinal and Common Yellowthroat. Twelve species have been sighted only once, and 21 species have been tallied every year during the 14 surveys. Population trends are evident. For example, the population of five Thrushes (Eastern Bluebird, Hermit Thrush, Wood Thrush Veery and American Robin) when taken collectively shows a marked decline between the first and second half of the surveys. From 1987-1993, the average number of Thrushes was 14.6, whereas the average number from 1994-2000 was only 4.7 individuals. During the past 6 years, this data was made available to the Wisconsin Breeding Bird Atlas.
MAPS Bird Banding at RNC
A. Sherkow and D. Hartmann, et al.
A MAPS (Monitoring Avian Productivity and Survivorship) banding station was established at RNC in 1999. The MAPS program is designed to provide critical information on the land birds of North America, which will direct the efforts to conserve avian diversity.
The project extends over ten years and is based on constant-effort mist netting and banding in the same location during the nesting season. Eighty-nine species have been identified in the area and 26 of those species were confirmed to be breeding. Three hundred eight six individuals of 41 species have been banded. Gray Catbirds were the most frequently banded (72) during the first two years, and 51 Black-capped Chickadees were banded.
In 2000, a number of birds banded the previous year were recaptured including: Blue-winged Warbler, Common Yellowthroat, Field Sparrow, Gray Catbird, Traill’s Flycatcher, Indigo Bunting, and Song Sparrow. Unusual captures included a Brewster’s, Warbler which is a hybrid of the Golden-winged X Blue-winged Warbler.
A one-day butterfly count has been conducted at the RNC and the nearby Cedarburg Bog between June 21 and July 9 since 1987 except for 1999 when weather conditions prevented the count. Similar counts are made at numerous sites in Wisconsin and across the nation.
The number of species seen and counted has ranged from 23 (1996) to 40 (1994), while the number of individuals between 261 (1987) and 1,005 (1995). Sixty-one species have been identified over the 13 years of the count. This annual survey assists in defining butterfly distribution and butterfly trends. Species that have been observed every year are the Spring Azure, Pearl Crescent, Baltimore Checkerspot, Northern Eyed Brown, and Little Wood Satyr. Occasionally, a butterfly species population explodes. For example, in the 1987-91 counts, only three Painted Lady butterflies were tallied. In1992, 113 were counted, and in 1993 none were encountered. This population explosion probably mirrored unique weather conditions in its southern refugia.
The data from the count is submitted to the Xeres Society, which coordinates a nation- wide survey. This helps paint a picture of butterfly distribution across North America. As a result of this survey, a checklist; “Butterflies of Riveredge” is now available to visitors.
Evaluation of the Engineered
Wetland Wastewater Treatment System at RNC
In the summer of 1998 RNC transferred the treatment of all of its wastewater to an Engineered Wetland Wastewater Treatment System. The system consists of two lined cells, each 45 ft x 60 ft x 1 ft. The cells are filled with 10 in of pea gravel and topped with 3 in of organic compost. A variety of native prairie plants suitable for wet soils was planted in each cell (2000 + plants per cell). Untreated wastewater is discharged into cell one and eventually flows into cell two before discharge to a natural sedge meadow. As it passes through the beds, bacteria break down the organic matter and nutrients are removed by the plants, with the result that the wastewater is discharged “cleaner” than other treatment systems and exceeds all minimum state standards.
Samples of the effluent were evaluated quarterly by the Port Washington Sewage Treatment plant staff and the Milwaukee Metropolitan Sewage System staff. The important water quality parameters are all well below state limits. The EWWTS is doing an excellent job of cleansing RNC’s wastewaters.
Ammonia, nitrite and nitrate
Maple Syrup Production in the RNC Sugarbush
Maple syrup production has been recorded every year since 1979 except 1984 when no trees were tapped because of drought conditions. Production has ranged from a low of 23 gal in 1979 to a high of 100 gal in 1994. The annual average production is 61 gal; the annual median is 64 gal.
Breeding Frog and Toad Survey
RNC Staff, et al.
Over the past 13 years, the breeding frog and toad populations at RNC and nearby wetlands have been surveyed as a part of a statewide effort to assess the status of these species across WI. The presence and stability of these populations reflect on the quality of the environment. Frog vocalizations, both in kind and volume, serve as a good indicator of breeding populations. Because each species has a different calling period, counts are made in April, late May and early July each year. The species heard in these counts were the Wood frog, the Spring Peeper, Chorus frog, Leopard frog, Eastern Gray Tree frog, American toad, and Green frog. No discernable change in the populations of these species was noted during the span of this study suggesting that the breeding grounds of these populations are not changing significantly.
Gypsy Moth Monitoring at RNC
USDA and M. Holleback
The Gypsy Moth is native to the forests of Europe, and first appeared in the United States in 1868. From New York, they have slowly extended their range westward appearing in Wisconsin and at RNC in 1968. As a means of monitoring the presence and population of the moths in area, traps baited with pheromone were set out to capture any Gypsy Moth adults. In 2000, the average number of captures/trap was 147 individuals; RNC trapped 64.
RNC Christmas Bird Count
M. Holleback and A. Larsen
An annual Christmas Bird Count (CBC) has been coordinated by RNC since 1969. The count area is a circular area with a 15 mi diameter. The center of this circle is located at the intersection of State Highway 33 & County Highway I.
A low of 40 species was counted in 1970 and 1979 and a high of 82 was counted in 1999. In seven of the last eight years, over 20,000 birds were counted. Until1988, the number of waterfowl comprised 1-11% of all individuals. Approximately 10,000 Canadian Geese were counted in each of the last two years. A total of 136 species have been tallied on the 34 counts. In recent years the RNC count has ranked among the top five counts in WI for number of species counted and is usually second only to Madison in having the largest number of observers; about 100. Results of the CBC are published in the “Passenger Pigeon”, the quarterly journal of the Wisconsin Society for Ornithology.
Relationship Between Maximum and Mininum Temperatures
and Sap Flow in the RNC Sugarbush
Daily maximum and minimum temperatures are recorded in the RNC sugarbush. The often cited maxim states that sap flows best when cold (below 0 deg F.) nighttime temperatures are followed by daytime temperatures above 30 degrees. This maxim is not substantiated by the RNC data. This is especially true as the weather warms in late March and early April. Late in the season the highest flows often occur when warm days follow warm nights. A different mechanism of sap flow as the weather warms is needed.
Swamp Metalmark Reintroduction Project
S. Borkin, MPM
The swamp Metalmark butterfly, Calephelis mutica, is the only member of the Riodininac that occurs in Wisconsin. Both the alkaline fens where the butterfly lives and populations of the butterfly are rare in the state. Reflecting this, the butterfly was listed as a state endangered species in 1989.
Swamp Metalmarks were first reported at RNC in the mid-1970s, but by the early 1990s, it was no longer found. Following selective tree and brush removal (primarily Ninebark and Tamarack) in the fen-like area at RNC, efforts to reestablish the butterfly were initiated in 1994 with the translocation of adults from other population sites and larvae raised from eggs laid by a captive female. The population was monitored by counting larvae found on host Swamp Thistle plants. Distribution within the habitat was noted also. In 1999 and 2000, no additional adults or larvae were introduced.
The population level in 2000 was nearly identical to that of 1999, which may indicate that the site in its present condition has reached its carrying capacity. In fall of 2000, 17 host plants hosting 38 larvae were located. These will continue to be monitored. Long term monitoring of this population is essential to obtain baseline information to learn more about natural fluctuations due to weather and to develop guidelines for best management practices.
Vegetation Survey of RNC
A. Larsen, L.Olsen, L. Zimmerman, et al.
The vegetation survey of RNC is a work in progress. The current list stand at 645 species of angiosperms and gymnosperms (flowering plants), 15 species of ferns & equisetum (pteridophytes), 95 species of fungi, and no documentation of algae, mosses, or liverworts. The list includes information on habitat, flowering period, and common name.
The Effect of Four Different Treatments of Litter on the Prairie
A. Larsen, et al.
A prairie planting has been divided into four plots and each of those four plots divided into four subplots. Each of the four subplots receives the following treatment: one is mowed and raked, one is mowed only, one is burned and one receives no treatment. The plots will be examined for differences in vegetation and soil development in the future.
Completed Studies and Research
A 12-year Study of Road Killed Animals
Along an 11-mile Stretch of Ozaukee County Highway
Over a period of 12 years, observations of road kills encountered along an 11-mi length of county highway in Ozaukee County were recorded. Each fatality was recorded as to species, ¼ mile section of highway in which fatality occurred, and date of observation. Later, the habitat within a corridor of ¼ mile on either side of the highway was mapped using aerial photos and was “ground truthed.”
During the survey 1,590 individual animals representing 74 species were found. The American Robin was the most common fatality with most of its mortality encountered during the April courtship period. Some animals showed high fidelity to particular sections of the highway. The 13-Lined Ground Squirrel was only encountered along the most rural parts of the highway adjacent to pasture areas. Some roadway sections were especially dangerous for wildlife, those being major intersections and waterway crossings. No relationship between other habitat aspects could be identified.
Of special interest is the occurrence of domestic cats. Cat fatalities were usually adjacent to residences as would be expected, but the temporal nature of these fatalities is puzzling. Cat mortality was noted in every month except September. What is unique about this month insofar as the cat’s exposure to highway mortality?
The seasonality of fatalities among the many of the other species reflects on their behavior (i.e., mating, caring for young, teen-age innocents, migration and hibernation).
A Simplified RNC Soils Map of
F. Hole, WI Natural History Survey
A detailed soils map of RNC indicates 24 different soils. The simplified map depicts nine major soils including Adrian Mucky Peat, Boyer Loamy sand, Casco Loam, Fabius Loam, Fox Loam, Fox Sandy Loam, Houghton Mucky Peat, Mussey Loam, and Wet Alluvial land. The soils are depicted on the map in a fashion that shows their relationship to the topography of the land.
A Study of the Vernal Pond at RNC
The vernal pond was studied intensively during three spring (March-April) visits. Temperature of the water and air and dissolved oxygen were recorded on each visit. An inventory of animals and their development was made. The succession of species over that period is discussed and the relationships that exist between these species one with another and with their changing environment is brought into focus.
Bird Banding of Resident and Migratory Birds at RNC
Since 1974 bird banding has been continuous but not always supported with the same effort. During that period all songbirds netted were banded and the data recorded with the Bird Banding Office of the U. S. Fish and Wildlife Dept. During that period 4,382 individuals representing 111 species were banded. Of those individuals four were recovered by other banders. A Bluebird was recovered in Michigan, a Grackle in Tennesee, a Goldfinch in Waukesha and a Red-winged Blackbird in Louisiana. Many banded migratory individuals were recaptured in successive years, the most remarkable was a Mourning Warbler that was recaptured at the precise location at which it had been originally banded two years earlier. It is suspected that this was accomplished following two round trips to Central America.
This banding continues to reaffirm that Riveredge is not an island onto itself but is part of a bird’s habitat that may extend to South America.
Bluegill Population Survey of RNC Farm Pond
A mark recapture survey was conducted on the farm pond at RNC in 2000. The population size was estimated at 155 bluegills. Weights also were recorded for the captured fish. Sizes ranged from 0.5 oz to 17 oz. The average weight of the captured fish was 4.7 oz. Assuming the pond is 1 acre (2.46 ha), the standing crop of Bluegills is approximately 41 kg/ha. Similar studies in Illinois found between 56 and 84 kg/ha. The RNC pond is below average in standing crop but appears not to be dominated by stunted fish, a sign that Largemouth Bass predation is keeping the Bluegill population in check.
Chickadee Populations and Longevity
The winter population of Black-capped Chickadee was determined using mark-recapture and subsequent analysis of the data using the Schnabble Method.
Over three years of effort, 57% of those banded were recovered during the first year, 16% were recovered the second year and 2% were recaptured the 3rd year.
Collection of Some Fishes of the Milwaukee River
B. Esselman and T. Onash
In the summer of 1986, seining took place at five locations along the Milwaukee River in Washington and Ozaukee counties. Five families of fish including seven game or pan fish species were collected. These were; Northern Pike, Largemouth and Small Mouth Bass, Black Crappie, Pumpkinseed, Rock Bass and Yellow Perch. With the exception of the Crappie all game fish were found at sampling points upstream from the Hwy 57 bridge at Saukville.
Deer Tick Survey at RNC
University of Illinois Medical College
In the summer of 1988, medical entomologists from the Univ. of Illinois under a grant from the Center for Disease Control surveyed several sites in southeastern Wisconsin for the presence of the deer tick, Ixodes dammini. RNC was one of the survey sites. Despite an intensive search, no ticks of any sort were found. This news was received with relief.
Earthworm Activity at RNC
Earthworm middens were surveyed in the RNC forest. The greatest numbers of earthworms were found in a fine silt loam and the fewest were in sandy soils. This distribution obviously reflects the higher moisture holding capacity of the silt loam and to the reduced abrasion on the earthworm gut. Soil texture, moisture and food supply interact to affect the distribution of earthworms in this forest.
A. Larsen, S. Putz, and P. McKenzie
An inventory of the dragonflies that occur at RNC is underway. To date 18 species have been recorded. The occurrence of the Slaty Skimmer established a new range record in the state.
Factors Affecting the Germination of Prairie Seed
A. Heon and A. Larsen
The combined experience and research of A. Heon and A. Larsen with the production of prairie plants from seed, resulted in the publication of “Begin With a Seed: The Riveredge Guide to Growing Wisconsin Prairie Plants.” Five hundred copies of this publication and 183 copies of the computer disk have been sold.
Fishes of the Milwaukee River at RNC
In 1989 and 1991, the Milwaukee River at RNC was surveyed by the DNR.
One pass of a stream shocker covered 1,400 m of the river. Stunned fish were collected and tallied by species and size. The survey identified 21 species including the state threatened Greater Redhorse. Of great interest is the increase in Smallmouth Bass populations in the 1991 survey as compared to the1989 survey. This increase could not be attributed to any specific factors.
Factors Affecting Maple Sap Production in the RNC Sugarbush
Three RNC Sugar Maple stands were evaluated for sap sugar content during the sugaring (March-April) of 1987 and 1988. In stand one, 55 trees were sampled, stand two had 30 trees and stand three had 36 trees. The sap of each tree was evaluated weekly over the 6-wk sugar’n season and diameter at breast height determined for all 121 trees. Diameter was chosen as an indicator of tree dominance. Based on this data, the average tree diameter for each stand was determined, the average sweetness of the sap was measured and a Productivity Index (PI) was calculated as Ave. % Sugar/Ave. tree diameter.
The data does not support any strong relationship between tree diameter and sugar production as the highest PI in 1987 was in the stand with the largest average tree diameter whereas in 1988 the highest PI was in the stand with the smallest diameter. The relationship between tree dominance diameter and sugar content in the maple tree remains clouded. Further study might focus on quantifying canopy size, soil moisture, or sap volume. The mystery of the maple remains.
History of Select Forest Stands at RNC
as Determined by Dendrochronology
A. Larsen, et al.
As an exercise in forest dynamics various stands have been studied repeatedly. Tree diameter, height and species were determined. Samples were taken with an increment borer and growth rate and tree age was determined.
The oldest tree identified at Riveredge began its life in the early 1800’s. However, studies on other forests have individual trees reaching back as late as 1725.
From these studies it can be stated that all stands at RNC reflect a logging event that occurred between 1840-1880. At this time most of the trees were cut leaving a few larger individuals standing. The stands exhibited a gradual recolonization and occasional grazing from the 1850’s through the 1960’s when the forest as we know it today was largely left untouched.
Improving Bluebird Nest Box Production
A concentrated effort to increase the production of Eastern Bluebirds and other native cavity nesting birds was initiated in 1980. After experimentation with different box types and placement, this research revealed that pairing boxes resulted in a lower Bluebird and Tree Swallow production rate. When the box numbers were reduced by ½ through the removal of one member of a pair, the number of Bluebirds nearly doubled.
May Day Bird Survey
N. Cutright, et al.
An annual count of all birds seen, heard or banded at RNC has been conducted on a single day in May near the peak of bird migration for the past 14 years. The number of species inventoried ranged from 82 to117.
Nitrate Levels in RNC Creek
Nitrate levels were measured at four points along the creek at RNC: at the headwater spring, adjacent to the farm field, the bridge in the forest and the junction with the Milwaukee River. The nitrate level adjacent to the farm field was approximately 40 times that of other sites along the river.
Notes on the Millipede, Pleuroloma flavipes, in Wisconsin
Mass aggregations are a poorly understood aspect of Pleuroloma flavipes life. In 1993, over 263 of these individuals congregated on the floor of the barn at RNC. Similar aggregations were observed in 1996 and 2000. These do not appear to be synchronous with major rain or other meteorological events.
A Phenologic Record of Natural Events 1969-2000
A daily record of natural events was maintained over this 31-year period.
The Small Mammals of RNC
During the summer of 1977, small mammals were trapped at RNC using live traps. One hundred traps were set along several transect lines over 11 nights. Fifty-five individuals were caught with White-footed mouse as the most common. Other species captured were Eastern chipmunk, Red-backed vole, Meadow vole, and the Meadow Jumping mouse. The researcher also learned that all of these species will bite when handled.
Stump Study of RNC Forest
A survey of the stumps remaining following a past logging were inventoried so as to obtain some idea of the historical composition of the forest. The stumps were identified on the basis of their wood characteristics. Fifty-eight stumps were identified. Of these 51% were Red Oak, 34 % White Oak, 5% Beech, 5% Elm, 3% Juglens species, 2% Basswood, and 2% Ash. No maple stumps were identified, reflecting perhaps the rapid decay of Maple wood.
Status of the Cooper’s Hawk in Wisconsin
R. Rosenfield, UW-Stevens Point and WDNR
Aspects of the breeding ecology of the Cooper’s Hawk were investigated at various sites in Wisconsin where Cooper’s nested. The study indicated that this species nest close to forest openings in forests with a high canopy closure. This was the case at RNC. An examination of Cooper’s Hawk eggshells indicated no thinning nor unusual concentrations of environmental contaminants.
On the basis of this study the hawk was removed from its threatened status.
Soil Phosphate Distribution
Using a method developed by Dr. R. Eidts to test for concentrations of soil phosphates, a suspected area of Indian habitation was surveyed. Dr.Eidts had previously used the test to successfully locate sites of probable historic human habitation as phosphates occur in fecal material, urine, saliva, wood fires, etc. The results from testing along the Milwaukee River showed that phosphates were in high concentrations throughout the site. This was likely due to the uniform distribution of mollusk shells, wood ash, and other waste products rich in phosphate. Hence the test proved inconclusive.
Sugarbush Insect and Disease Survey
M. Drilias, WDNR
The RNC sugar bush was evaluated for its general health as part of a statewide study of sugarbush health. The condition of the trunk and crown were noted. Most (98.9 %) of the Sugar Maples in the stand were considered in excellent health. Only 5.4 % showed sign of stem decay. Of the maples examined in the sugarbush, only 30.1% were tapped.
As a part of this study, soils were tested and found to be deficient in phosphorous, calcium and potassium. No evidence of these deficiencies was noted in the forest foliage.
Permanent plots were established as a part of this study.
The Effect of Soil Denitrification on Establishment of Prairie Plants
A. Larsen, C. Kenney, et al
Prairie plants are known to be tolerant of nutrient poor soils. To test this assumption paired plots (20 ft x 20 ft) were prepared for planting of prairie plants by spraying with herbicide and then rototilling thoroughly. One gallon of sawdust per square foot was added to one plot of each pair. Fungi decomposing the sawdust would extract considerable nitrogen from the soil, leaving the soil impoverished in this essential plant nutrient. The sawdust was mixed into the upper 4 in of soil before planting of the plots. Each pair of 13 plots was planted with 9 oz of prairie forb and grass seed, each having a different seed mix.
After two years, the number of native species on the treated plots exceeded the plots without sawdust, and after tree years the biomass production on treated plots was nearly two times that on untreated plots. Non-native plant species such as the Sweet Clover made up the greatest part of the biomass on untreated plots, and native plant species were more common at the end of three years on the treated plots.
This study demonstrated the advantage of planting prairie species on poorer soils where they are more competitive than are non-native species.
University Wisconsin-Milwaukee Completed Master’s Thesis
Swartz, B. P. 1977. A management plan for a swamp forest based on
vegetation analysis. M.S. Thesis. University Wisconsin-Milwaukee. 83p.
A 35-acre swamp forest within the RNC was found to have five plant communities based on similarity indices, including Shrub Carr, Alder thicket-Black Ash forest, Cedar swamp-Black Ash forest, Birch-Tamarack forest, and northern wet-mesic forest. A management plan is proposed based on maintaining the greatest possible number of different communities. Some portions of the wetland show an affinity to the Northern White Cedar swamps and others to the southern lowland forests. Most of the area was probably a Tamarack-White Cedar swamp in presettlement times. The high importance for Paper Birch is evidence of disturbance when the area was settled. The importance of Red Maple, Black Ash, and American Elm in the tree stratum suggests that the forest is changing from conifer to hardwood swamp. Shrub composition also indicates the changing nature of the stand, with Alder thickets remaining along the waterways and more typical southern Shrub Carr species prevalent in disturbed portions. Grouping of herbaceous species also suggests that succession has proceeded at different rates in different parts of the stand. Water flow into the stand when the surrounding land was converted to cropland may have influenced plant succession in portions of the forest. Management recommendations fall into two categories: removal of vegetation to alter the rate and/or direction of succession and restoration of missing species to alter composition of selected areas. Plant species identified in the study area totaled 105.
Paul, R. K. 1970. A geological resource guide to the RNC, Ozaukee County, Wisconsin. M.S. Thesis. University Wisconsin-Milwaukee. 84p.
A geological resource guide for teachers using the RNC is presented. In-depth information on geology and a variety of student projects are presented for teachers who plan to incorporate fieldwork at RNC into their classroom curricula.
RNC was entirely covered by glaciation during the Pleistocene. The kame and kettle topography that occurs at RNC reflects stagnant, thin ice of the Woodfordian Lake Michigan glacier. The composition of the drift is primarily Paleozoic lithologies, although 11% consists of Precambrian material derived from localities outside WI. The only bedrock exposed at RNC is a single outcrop located along the Milwaukee River. This rock is the Racine Formation of the Middle Silurian Niagaran Series. It is comprised of calcareous sediments that were later dolomitized. RNC is located within a trend of shallow bedrock. The Casco and Fox series of soils at RNC are silt loams developed from glacially transported materials and strongly reflect the underlying Silurian dolomite.
Purtell, H. M. 1984. Factorial ecology of the vegetation and soils in a disturbed riverside oak-maple woodland in southeastern Wisconsin. M.S. Thesis.
Univerity Wisconsin-Milwaukee. 186p.
The spatial relationships of soil and vegetation were examined at RNC. The nine sites that were sampled include two Milwaukee River bank sites, four upland forest sites, and three lowland sites. The seven soils of the area were all derived from glacial till and outwash. A strong correlation was found between the levels of clay, silt, magnesium, phosphorous, and potassium. Presence of lowland plant species was correlated with high sand, calcium, nitrogen, and organic matter levels. Topography, including slope and depth to water table, was the major factor determining plant distribution. Topographic positions also determined soil moisture, aeration, and nutrients, as well as the microclimates of north and west facing banks and the lowland. Time was the most important factor in the process of soil formation. Time also influenced plant succession, as did human activity. Land survey records indicate that in 1835 American beech and Sugar Maple comprised 54% of the trees. In 1983, 55 years after the forest was logged, 22% of the trees were maple and beech. Red oak and green ash, of intermediate tolerance, had gained prominence. Identified in the study area are 133 plant species.
In addition the Center was utilized as a comparative site in the following studies conducted by University Wisconsin-Milwaukee graduate students and professors.
Reinartz, J. & D. Les. 1994. Bottleneck-induced Dissolution of Self-Computability and breeding System Consequences in Aster furcatus.
Reinartz, J. & J. Popp. 1987. Structure of Clones of Northern Prickly Ash
Les, D. & J. Reinartz. 1992. Distribution and Habitats of Forked Aster, Aster furcatus, A Threatened Wisconsin Plant.
Popp, J. & J. Reinartz. 1988. Sexual Dimorphism in Biomass Allocation and Clonal Growth of Prickly Ash
Kunowski, M. 1982. Introduction and Survival of Plantago cordata, an endangered species into suitable habitats.
Ficken, M. & C. Weise. 1984. Microgeographic Variation in a Complex Call of the Black-capped Chickadee.
Rendleman, B. A. 1990. Individual Variation in Songs of Male northern Cardinals.
Lohe, B. S. 1989 The Organization of Song Elements in the Gray Catbird.
Downey, H. A. 1996. Reponses of Black-capped Chickadee Flocks to Playback of Different Alarm Calls.
Abbey, C. 1979. Responses of Black-capped Chickadee to Playback of their Own Vocalizations.
May Day Inventory
Wisconsin Breeding Bird Atlas participation