Oak Openings Site Conservation Plan
REGIONAL DESCRIPTION AND BACKGROUND
The Oak Openings Region is a 130 square mile (Moseley, 1928) (Figure 1) area located in Lucas, Henry and Fulton Counties of Ohio. The region supports a mosaic of Great Lakes Twig-rush Wet Meadow (Wet Prairie) (G1Q), Great Lakes Swamp White Oak - Pin Oak Flatwoods (G2), Mesic Sand Prairie (G2), Midwest Sand Barrens (G2/G3), Black Oak / Lupine Barrens (Oak Savanna) (G3), and Black Oak - White Oak / Blueberry Forest (Oak Woodland) (G4?) communities that developed on a series of post glacial beach ridges and swales. The area is entirely confined to the physiographic region known as the lake plain, a generally flat area formed under the influence of post glacial lakes. Historically, the Oak Openings extended across the Michigan state line at least into Monroe and Wayne counties and possibly as far as Detroit. Within Ohio, the original area may have covered over 300 square miles (Gordon, 1969) (Figure 2) and included parts of neighboring Wood County. Although remnants of habitat do still exist in these outlying areas, for the purposes of this Site Conservation Plan, "the Site" is the "Moseley region". This is a portion of Gordon's 300 square mile area identified by Edwin L. Moseley (1928) in his classic publication, Flora of the Oak Openings. At that time, and still today, this area represented the best preserved remnant of Oak Openings habitat in Northwest Ohio and Southeastern Michigan.
Previous to European settlement, the Oak Openings was a pocket of prairie and oak savanna nearly surrounded by the forests of the Great Black Swamp. This swamp, an area half the size of the Everglades, has been largely converted to agriculture. The Oak Openings, however, has persisted as one of the few landscape scale oak savanna/prairie complexes left in the midwest. The Oak Openings is the largest oak savanna/wet prairie complex in Ohio and it sustains more state listed species than any other region of a similar size in the state. Significant restorable examples of savannas, prairies, barrens and flatwoods exist on both public and private land throughout much of the region.
The Oak Openings region is part of a sand belt that extends for approximately 120 miles from northeast of Napoleon, Ohio to west of Detroit, Michigan. The sand within the Moseley portion of the region was deposited approximately 12,700 years ago as a series of beach ridges formed by post glacial Lakes Warren I, II, and III (elevations in chronological order, 690,682 and 675) (Forsyth, 1993) and Lake Wayne at 660 feet.
A glacial ice front in southern Canada functioned as a dam for the Warren Lakes and numerous others that occurred before and after. As the front of the ice oscillated back and forth, lake levels would rise and fall forming distinctive beach ridges at each new level. These ridges occur throughout northern Ohio, roughly parallel to the southern shoreline of Lake Erie. However, none approach, in the extent of surface coverage and sand depth, those found within the Oak Openings Region. The size of these sandy deposits is probably the result of two factors; the deposition of three beach ridges in the same general area and the fact that a large supply of sand was available north of the region during this deposition process. Glacial meltwater rivers, flowing through sandy outwash, deposited significant quantities of sand into Lakes Warren I, II, and III. Offshore currents moved the sand to the south and deposited it as a series of closely aligned beach ridges. However, southeast of the Oak Openings, very little sandy outwash was available and glacial meltwater was not present. Additionally, lake currents here moved from the east to west. The combination of these factors resulted in relatively small deposits of sand in the beach ridges east of the Oak Openings. As the glacial ice front retreated northward, all of these pre-Lake Erie beach ridges were isolated from what would ultimately become the present Lake Erie shoreline.
In the Oak Openings, the beach ridges are approximately 40 feet deep and were deposited over a surface of clay-rich glacial till. On the ground, the ridges are not obvious features. Their gradual increase in elevation over the surrounding terrain is often almost imperceptible. However on the surface of the ridges, small wind blown sand dunes developed which today gives portions of the region a visibly rolling topography. Relief of the dunes occasionally reaches 25 feet and elevations within the entire region are between 640-690 feet.
Although historical inventories of the Oak Openings are scarce, the map The Vegetation of the Oak Openings of Northwest Ohio at the Time of Euro-American Settlement (Brewer, Vankat and Walser,1993) (Figure 3) provides a plausible estimate. Compiled from survey records obtained from 1817 -1832, this map indicates the region was a mosaic of vegetation types, often influenced by topography. It is important to note that although Brewer's map and Moseley's map delineate the same general region, Brewer's area is over 50 square miles larger. This is likely because by 1928 a significant portion of the area that the surveyors had noted as "savanna" had already been modified.
The following vegetation descriptions are based on a combination of both Brewer and Moseley's work. Upland beach ridges and dunes historically supported approximately 60,000 acres (This figure combines Brewer's oak savanna and oak barrens communities) of oak savanna with a density of 2 to 17 trees per acre and an average of 6 trees per acre. Approximately 27,000 acres of oak woodland also occurred in these upland areas with a density of 17 or more trees per acre and an average of 36 trees per acre (Brewer, 1993). According to Moseley, dominant trees within these habitats were white oak (Quercus alba), black oak (Quercus velutina), sassafras (Sassafras albidum), and wild black cherry (Prunus serotina). Common shrubs included blueberries (Vaccinium sp.), huckleberry (Gaylussacia baccata), sweet-fern (Comptonia peregrina), New Jersey tea (Ceanothus americanus), and prairie willow, (Salix humilis).
Common and abundant grasses and sedges included little bluestem (Schizachyrium scoparium), sandbur (Cenchrus sp), various species of Panicum, big bluestem, (Andropogon gerardii), Indian grass (Sorgastrum nutans), june grass (Koeleria macrantha), Carex muhlenbergii, Carex pensylvanica and others. Common forbs consisted of wild lupine (Lupinus perennis), puccoon (Lithospermum sps.), blazing star (Liatris aspera), goldenrods (Solidago sps.) sunflowers (Helianthus sps.) and pinweeds (Lechea sps.).
Swales between the ridges and dunes supported approximately 32,000 acres (Brewer, 1993) of nearly treeless wet prairies. Sedges and grasses common in these areas included Carex lasiocarpa, Carex sartwellii, Carex lanuginosa and Calamagrostis inexpansa. Common and abundant forbs consisted of fringed gentian (Gentianopsis crinita), goldenrods (Solidago sps.), blazing star (Liatris spicata), and cowbane (Oxypolis rigidior). Trees and shrubs that were present included pin oak (Quercus palustris), trembling aspen (Populus tremuloides), dogwoods (Cornus sps.) and Spirea sps..
Historically, the Oak Openings, and much of Northwest Ohio, supported an impressive list of fauna that depended on the persistence of the natural ecosystems. According to Harold Mayfield (1976) in "Changes in the Natural History of the Toledo Region Since the Coming of the White Man", bison, elk, white-tailed deer, mountain lion, bobcat, grey wolves, black bear, beaver and porcupine were found in the Northwest Ohio area.
Birds were also a significant component of these communities. Naturalist Lou Campbell (Campbell, 1968) reported that sandhill cranes nested in the region until the 1880s. Mayfield reports that swallow-tailed kites, golden-winged warblers and various species of ducks frequented the wet prairies. Greater prairie chickens, wild turkeys, eastern ruffed grouse, Henslow's sparrows and lark sparrows were found in the uplands.
Selected insects, specifically the lepidoptera, depended upon the unique characteristics of the Oak Openings ecosystem. Butterflies like the Karner blue (Lycaeides melissa samuelis), the frosted elfin (Incisalis irus) and the persius dusky wing (Erynnis persius) were widespread in the region. These species thrived on a diversity of nectar plants and abundant populations of wild lupine, the host plant for their larva.
Two primary processes promoted the persistence of the black oak savanna and wet prairie communities. The rapid permeability and instability of the sandy soils discouraged the development of natural surface drainage. This combined with the impermeability of the underlying glacial till maintained a high water table in the swales throughout the year. During late winter and spring, groundwater levels would often be above the surface, with depths of several feet apparently not uncommon. In late summer and fall, levels would drop and the swales would dry. This extreme oscillation favored herbaceous vegetation and kept the growth of trees and shrubs to a minimum.
Fire was the second primary process involved in maintaining the Oak Openings communities. On the ridges and dunes, the savannas and woodlands experienced periodic fires that generally favored the growth of the herbaceous vegetation. Trees remained as part of the vegetative community in the uplands not only because of the better drainage, but also likely as a result of a variable fire frequency, weather conditions and soils. The wet prairies, although primarily influenced by groundwater, were, during dry periods, undoubtedly effected by fire as well. A draft ecological model for the Oak Openings can be seen in figure 7.
Our understanding of the impact animals may have had on the vegetation is minimal. Many of the larger mammals were extirpated from the region very early on and we can only speculate as to how their grazing and browsing may have effected the vegetation.
Settlement of the region by Europeans in the early 1800's brought dramatic changes to the natural system. Logging removed the old growth trees and grazing probably impacted much of the herbaceous layer. Farming converted large areas of the land to agriculture. Ditches, installed to improve drainage, lowered the groundwater in the wet prairies and increased the growth of woody vegetation. Fire suppression resulted in a rapid increase in woody growth within the savanna and very likely within the wet prairies as well. Today nearly all of the areas that remain in a "natural" condition are much more heavily forested than they were before settlement.
The majority of the oak savanna and oak woodland communities that were not destroyed have become heavily shaded oak woods or maple/oak woods. These areas possess little of the herbaceous prairie understory they once had. Leaf litter and duff accumulation have increased significantly which provides conditions suitable for more mesic, fire intolerant, species. What has survived of the wet prairie persists in relatively small pockets surrounded and fragmented by aspen/shrub thickets or dense stands of pin oak.
Many of the sites that were difficult to farm because they were either to wet or to dry were eventually abandoned and recolonized by native vegetation. Some wet prairie areas have recovered to the extent that it is difficult to decipher any human disturbance. Abandoned farms that were historically oak savanna have reverted to sand barrens,or essentially treeless savannas. These barrens have served as refugia for many sun-loving prairie species that can no longer persist in the excessively shady canopy of the former oak savannas. Still other abandoned agricultural fields, like some within the Oak Openings Preserve Metropark and Maumee State Forest, were planted in the 1930s with pines and other non-native conifers. No conifers are native to the Oak Openings Region and today these areas are monocultures essentially devoid of high quality native vegetation.
European settlement also had a profound impact on the region's original fauna. Except for the white-tailed deer, nearly all the large mammals were eradicated by the mid-1800's. The effect that some of these animals may have had on the vegetation we will probably never know. Certain species, like the beaver and the porcupine, may have had a profound impact through flooding and woody plant control. Others, like the bison and elk, may have modified the vegetation through browsing and grazing.
Waterfowl, apparently numerous in the wet prairies, are today either infrequent or have been extirpated. Many upland birds like the greater prairie chicken and the eastern ruffed grouse were eliminated in the early 1900's. Although the lark sparrow persists in limited numbers, Henslow's sparrow and the golden-winged warbler have been nearly extirpated.
Over hunting negatively impacted some of these animals, but it was fragmentation and destruction of habitat that probably eliminated many species from the region. This process is still ongoing with the most recent example being the extirpation of the Karner blue butterfly from the region in 1988. Habitat destruction in the form of fire suppression was likely the cause. The butterfly's sole larval food source, wild lupine, has been severely reduced because of excessive shading by woody plants whose growth is no longer deterred by fire.
The effects of the original settlement of the region are most pronounced along the margins and in the southern 1/3 of the area. Here the soils are richer and the drainage is better. A significant portion of these areas were converted to agriculture and are still used for that purpose. Today, however, it is the residential and commercial growth of the Toledo suburbs that threatens to eliminate much of what remains of the Oak Openings ecosystem. Most of the natural vegetation in the northeastern one-fifth of the region has been eliminated by urbanization. Much of what remains within the rest of the region is experiencing varying degrees of this same pressure. Presently, urbanization is most expansive in the northern half of the region.
Relationships need to be established within each of the region's political jurisdictions in order to inform and educate decision makers about the value of the Oak Openings system. Due to our private status, The Conservancy is often in a unique position to play this role. Among local officials, knowledge regarding the importance of the area is very low.
Most land use changes are made because of zoning decisions at the township level. Each township has a zoning board and township trustees. These two groups can have a significant impact on how a specific township will or will not be developed. At the very least, having their support is important and at the most, a well informed motivated trustee can help advance conservation. Generally, township trustees have the final authority regarding zoning changes. This can be important because most sub-divisions require zoning changes. Theoretically, in the process of granting a change, stipulations could be placed on the approval that would favor conservation. Land annexations issues are ultimately handled by the County Commissioners.
Within Lucas County, the Toledo - Lucas County Plan Commissions can also play an instrumental role in the land use process. This commission reviews various proposed zoning changes and provides recommendations to the township trustees. The trustees however, have the final decision.
The region is covered by three counties, each of which is governed by three County Commissioners:
Eight townships occur within the region, each governed by three township trustees. Each township also has a zoning board that provides recommendations to the trustees. The townships can be divided into three fairly distinctive categories:
The City of Toledo, City of Sylvania, Village of Holland and the Village of Whitehouse also occupy a portion of the region. Much of the land within these municipalities is urbanized. A notable exception to this is the unprotected Holland Sand Barrens site in Holland.
Ohio Congressional district 9 is an important part of the conservation of the region. This district contains the bulk of the Oak Openings habitat and represents all of Lucas and Fulton County.
Ohio Congressional district 5 represents numerous northwestern Ohio counties including Henry County. A relatively small portion of the Oak Openings occurs within the Northwestern portion of this county.
Ohio Senate districts 1 and 2 represent the entire Oak Openings Region with district 2 covering all of the area within Lucas County.
Ohio House districts 49-52 represent Lucas County, 82 represents Fulton County and 83 covers Henry County.
The majority of the Oak Openings Region is located in Lucas County with the remainder falling within portions of Fulton and Henry counties.
Approximately half of Lucas county is urbanized and occupied by the City of Toledo, City of Slyvania, City of Maumee, smaller villages and several urbanizing townships. The majority of the western portion of the county, where the Oak Openings Region occurs, is still in rural condition. However, residential and commercial development is primarily moving west from suburban Toledo and into the Oak Openings.
The population of Lucas County in 1990 was 462,361 and the population is expected to increase 0% to 9%. In 1992 the per capita income was $19,371 and the poverty rate was 18.6%. In 1991, manufacturing was the largest source of payroll in the county making up 26.9% of all jobs and employed 35,352 people. The second largest source of payroll was service jobs which made up 26% and the third largest payroll job was wholesale and retail which made up 17.5%. Agriculture and fishing were the second smallest payroll source with 0.4% of all income.
Fulton County is primarily rural. The population in 1990 was 38,498. The population is increasing and is expected to be 43,800 in the year 2015. The per capita income in 1992 was $19,020. Manufacturing is the largest employer. In 1992, 12.9% of the employment was in manufacturing. The second highest employer is farming with 2,579 jobs.
Henry County is primarily rural. The population in 1990 was 29,108. The population is expected to increase to 32,600 in the year 2015. The per capita income in 1992 was $17,842. The largest employer is manufacturing with 4,448 positions in 1992. The second highest employer is farming with 2,579 jobs.
A more accurate reflection of the population within the Oak Openings Region would be based on population numbers for the nine townships within the region. According to 1990 figures, approximately 69,000 people live within the region. This figure is actually somewhat lower because not all of each township necessarily occurs entirely within the region.
Currently, the southern 1/3 of the region is primarily used for agriculture with the production of corn and soybeans being the major crops. The northern 2/3 of the region is primarily used as rural residential, urban residential and commercial establishments. Much of the growth in residential and commercial development is occurring within Lucas county. Although population growth figures do not indicate a dramatic increase for the county, these figures are somewhat misleading as for the impact on the Oak Openings Region. The majority of the development taking place within Lucas County is a result of displacement of the population within the Toledo Metropolitan Area. While the population within the city of Toledo continues to decline, in the suburbs and outlying areas it is on the rise. This displacement of the population is fueling the development of the Oak Openings Region.
Recently projected growth plans (1998) for the Toledo Express Airport indicate a desire by Port Authority Officials to develop the Toledo Express Airport into an air/truck/rail cargo hub. Such a hub would also support a variety of businesses (light manufacturers and warehouses) adjacent to the transportation infrastructure. Port Authority officials have considered supporting a bill which would provide them with zoning authority for an undetermined pre-described zone around the airport. This would presumably permit control over growth in the short term so that long term air cargo hub development goals could be met. This zoning proposal appears to have little support currently. The extent of the development around the airport is dependent upon the availability of federal funds.
In the short term, through the use of eminent domain and willing sellers, the Port Authority is purchasing numerous (50-100) residences around the airport. Most of these are sold at low cost, moved and many are relocated onto Oak Openings habitat. This house relocation effort has played a role in raising the cost of land within the area that the Conservancy's is acquiring property.
Expanding and maintaining oak savanna and wet prairie habitat throughout the Oak Openings Region is impossible for the Conservancy to accomplish alone. It will take the efforts of many individuals, agencies and institutions. With this in mind, formal and informal partnerships are an important component to our work.
The Oak Openings Working Group (Figure 4) has been established to provide a format for dialogue among interested parties. Within the group, interest and commitment levels vary and the purpose is currently an informational/motivational one more than an action oriented one. Issues that may require specific actions are better addressed by small components of this group or other less formal partnerships.
Another partnership group, The Ohio Karner Blue Recovery Team (see appendix), of which the Conservancy is a member, is developing a plan to reintroduce the federally endangered Karner blue butterfly into the Oak Openings Region. The completed plan will be produced and authorized by the ODNR - Division of Wildlife. It represents a true partnership approach since no single agency is capable of reintroducing this species on its own.
Key partnerships exist with other land owning and managing agencies within the region. These include the Metropolitan Park District of the Toledo Area, Ohio Department of Natural Resources - Division of Natural Areas and Preserves (ODNR-DNAP), ODNR-Division of Forestry and the Toledo Express Airport (Figure 5). These agencies are as follows:
Four broad ecological goals have been identified for the region:
The Oak Openings region supports five communities of global significance, Great Lakes Twig-rush Wet Meadow (Wet Prairie) (G1Q), Great Lakes Swamp White Oak - Pin Oak Flatwoods (G2), Mesic Sand Prairie (G2), Midwest Sand Barrens (G2/G3), and Black Oak / Lupine Barrens (Oak Savanna) (G3). Although the Conservancy's focus in the region is at the community level, selected highly ranked species are of a particular interest.
The Karner blue butterfly (G2), a federally endangered species, was extirpated from the region, and Ohio, in the late 1980s. Reintroduction plans are presently being formulated by the Ohio Karner Blue Recovery Team (OKBRT). OKBRT is a partnership that includes the Conservancy, The Metropolitan Park District of the Toledo Area, ODNR - Division of Wildlife, ODNR - Division of Forestry, ODNR - Division of Natural Areas and Preserves, Toledo Express Airport/Toledo-Lucas County Port Authority, The Toledo Zoo and the USFWS.
Skinner's false foxglove (Agalinis skinneriana) (G2) is the most highly ranked plant species within the region. Within the region, only one secure location is currently known. Even at this site, population numbers fluctuate widely. According to Gleason and Cronquist (1991), A. skinneriana prefers dry prairies, open woods, and barrens, especially in sandy soil. Within the Oak Openings, a preference for somewhat mesic sites has been noted. More research is needed to determine the best approach to protect this species.
According to ODNR - DNAP Heritage Data Base, 177 rare species occur within the region, more than any area of a similar size in Ohio. For a complete list of these species see figure 6.
Seven primary stresses have been identified for the Oak Openings Region. In order of significance they are loss of habitat, fragmentation of habitat, woody plant succession, groundwater lowering, exotic plant species and elimination of native species. An analysis of each of these primary stresses follows.
Loss of Habitat
This is unquestionably the most imminent and permanent stress on the Oak Openings system. Historically, the source of this stress was from the conversion of the land to agriculture during the 1800s and early 1900's. Through an analysis of maps generated from land survey records, the Oak Openings Region may have originally covered over 300 square miles. The largest remaining relatively contiguous area today is a 130 square mile region known as "Moseley's boundary". Although habitat remains in the region outside of Moseley's boundary, much of it is believed to be significantly fragmented and isolated. Even today within this 130 square mile, nearly 50% (Frost, 1994) of the area is currently in agriculture. Factoring all this in, approximately 200 square miles of the Oak Openings Region has been converted to agriculture.
Today, the most significant source of habitat loss in the Oak Openings Region is development. Residential, commercial and industrial development all occur within the area as suburban sprawl spreads west from the City of Toledo and its environs. Residential development, both individual home sites and subdivisions, is the most serious problem with activity occurring throughout most of the region. Although the entire region is experiencing development pressures, the southwestern 1/3 remains mostly rural, although most impacted by agriculture.
The infrastructure necessary to support the development (such as roads, pipelines and utilities) is an additional source of stress. The region is dissected by a network of roads around each square mile survey section. Within the more urbanized areas, residential roads cover much of the land. Both I-475 and I-80/90 cross the region and have eliminated significant areas of habitat. When seeded into non-native species, pipeline and utility corridors have also eliminated habitat.
The construction of ponds and sand mines has two detrimental effects on the Oak Openings ecosystem; modification of groundwater levels, which will be discussed later, and destruction of habitat. For the purposes of this discussion, ponds are small bodies of water (1-5 acres) that are generally excavated for the use of the individual home owner. Sand mines are larger (5 - 200 acres) and are initially excavated for obtaining sand for construction projects. Once completed, these "lakes" often serve as attractive sites for new housing projects.
Often the scenario for pond construction is to excavate in the lowest area of the property, and then utilize the excavated sand to fill adjacent areas for a house site. In this process, much of the native vegetation is eliminated. With sand mines, habitat is destroyed in the same manner with one exception. Typically the sand is used off-site for basement back filling, septic systems or as fill dirt.
Two additional sources of habitat loss include conversion of oak savannas to non-native conifer plantations and logging of older growth savanna trees. Both of these are considered to be relatively minor sources. Most of the conversion to conifer plantations occurred in the 1930's and 1940's within the Oak Openings Preserve Metropark, Maumee State Forest and surrounding area. These trees are today reaching maturity and little new planting seems to be occurring. Changes within the wood product market could theoretically alter this trend. Logging of remnant savannas occurs periodically in the region and the removal of these larger trees is perceived to be detrimental. However, very little is known about how this may affect the long term health of the savanna community.
Fragmentation of Habitat
As described above, various types of human activities (i.e. conversion to agriculture, development etc.) have resulted in a significant loss of habitat within the Oak Openings Region. These same activities have also extensively fragmented the habitat that remains. Since European settlement, much of the area has become a growing patchwork of houses, roads and buildings interspersed among areas of natural habitat. Fragmentation within the Oak Openings Region should be considered in a relative manner. Even the largest conservation area within the region (Oak Openings Preserve Metropark, 3600 acres) is significantly fragmented when compared to its historical condition. An acceptance of a certain degree of fragmentation is necessary when analyzing the quality of habitat that remains.
Today, the major source of habitat fragmentation in the Oak Openings is development and its associated infrastructure. Although fragmentation occurs anytime habitat is destroyed, it is most severe in the case of individual large lot (two or more acres) residential development. Although this type of development appears more environmentally friendly on paper because the density of buildings is less, this type of housing can significantly fragment the landscape under certain scenarios. The placement of a house and its associated infrastructure in the middle or near high quality habitat can effect the neighboring vegetation, hydrology and fauna by creating edge effects, modifying groundwater, introducing exotic species and creating management problems. Large lot development is a problem throughout the region with the southern portion of the area under the greatest stress.
Woody Plant Succession
The most significant biological threat to the Oak Openings Region is the succession of historically "open" oak savannas and wet prairies into oak woods and pin oak/aspen thickets. It has been through this process that many individual species have become rare and the region's original plant and animal communities have been drastically modified.
Fire suppression, beginning with European settlement and continuing to this day, has virtually eliminated a critical process by which the growth, distribution and density of woody vegetation was balanced with that of the grasses and forbs. Without fire to deter growth, trees and shrubs have established a canopy whose shade subsequently inhibits the growth of sun loving grasses and forbs. While fire negatively impacts many woody plants, it is advantageous to most savanna grasses and forbs. Nutrient recycling, litter reduction and seed scarification are but a few of the positive factors which fire contributes to these plants. As a result of fire suppression, most of the oak savanna in the region has succeeded into various types of woodlands.
In the wet prairies, the loss of fire has also likely had a negative effect, although it is the lowering of the groundwater table that has been most detrimental. Areas that were historically deep enough on which to canoe and ice skate are today much drier. Although some wet prairie areas still maintain standing water in the winter and spring, many have been completely eliminated by groundwater lowering. Those that have survived are extensively affected by succession of woody plants.
The reintroduction of fire into these human modified landscapes through the use of prescribed burning can in itself be a potential source of stress. If fire is not used in a judicious manner, it can become a stress on the system by destroying vulnerable populations of insects.
The loss of large ungulates is a perceived potential source of stress that has presumably facilitated the succession of woody plants. The extent of the impact on the vegetation by grazing and browsing by elk and bison will probably never be known. These animals were extirpated from the region before any data or even significant observations could be made.
As described above, groundwater lowering is a source of the stress for woody plant succession. It can also be considered a stress itself, such as when the lowering effects vegetation that requires certain soil saturation levels to survive. Wet prairies that have been completely drained essentially "dry up" and will no longer support selected species, even if woody plant encroachment is not a problem.
The construction of ditches began in the mid 1800s and has been the primary force for groundwater lowering in the region. Major ditches like Wiregrass, Prairie and Drennan, located in the northern section of the region, were installed to help drain the extensive (4500 acre) Irwin Prairie. Roadside ditches that form almost a grid-like pattern over the region have probably had the most significant impact on the region's hydrology (Forsyth, personal communication).
Sand mines also have an impact on groundwater levels. This effect is most pronounced when pumping is utilized to lower the water to facilitate efficient extraction of the sand. When the pumping is stopped groundwater levels will eventually rise to near pre-mining levels. The surface of the water in the remaining lake will then closely reflect the level of the surrounding groundwater. However a cone of depression that surrounds the remaining lake will persist forever (Braun, personal communication). In certain instances, after the mining process is completed, the water level of the lake is maintained at an artificially low level. This in turn promotes artificially low groundwater levels in the adjacent area.
The effect that these sand mines have on nearby areas is inconclusive. A general premise is that the larger the sand mine the greater the impact it has upon the groundwater within the region.
Exotic Plant Species
Non-native plants, or exotics, serve as a source of stress in the Oak Openings system in primarily two ways. They can be intentionally planted, such as in the case of turf lawns or landscaping plantings, or they can result from a natural dissemination process (bird droppings, wind, etc.) that permits colonization of natural areas from the surrounding planted or previously infested areas.
The most serious problem is the intentional replacement of native plants with non-native turf grasses. In both residential and commercial construction projects, the existing vegetation is usually severely modified. A percentage of native trees are normally maintained while the grass, forbs and shrubs are eliminated. These plants are replaced with turf grasses and non-native forbs and shrubs.
A slower and less obvious threat is the spread of exotics into high quality natural areas. Shrubs such as European buckthorn,(Rhamnus frangula), common buckthorn,(Rhamnus cathartica) and autumn olive, (Eleagnus angustifolia) are a problem. Exotic herbaceous plants, such as garlic mustard, (Allaria petiolata) and bouncing bet, (Saponaria officinalis) are also troublesome within some parts of the region. Each of these plants can rapidly colonize existing natural communities and displace the native vegetation. This colonization is usually facilitated by alterations of the regions natural processes (i.e. groundwater lowering, fire suppression).
Several species are currently not an enormous problem, although they have the potential to be in the future. Purple loosestrife (Lythrum salicaria) and phragmites (Phragmites australis) occur within the region but have yet to reach the extent where they are a widespread problem. However, the presence of these plants is troublesome because of their proven potential to rapidly colonize new areas.
The infestation of exotic species is spotty within the region. Selected areas are heavily infested, while in others they may be practically non-existent. In general, the region has fewer exotic species problems than many other areas of Ohio.
Elimination of Native Species
In our analysis, this stress applies to insects and most directly to Lepidoptera (Butterflies and Moths). The two primary sources of this stress are insecticide spraying and fire.
Insecticides are commonly sprayed throughout the region to control adult mosquito populations. These insecticides can have a detrimental effect on both adult and larval stages of butterflies and moths, several species of which are known to be components of the oak savanna community. The Karner blue butterfly, the most notable because of its status as a federally endangered species, was extirpated from the region in the late 1980's. The reason for its extirpation is not clear and no direct link with insecticides is inferred here. It is clear, however, that insecticides kill insects and heavy use in an area where butterflies and moths persist is presumed to be detrimental.
Although fire is a critical force in maintaining habitat for savanna butterflies and moths, in certain instances it can also prove to be detrimental. Most species are not directly fire tolerant, but thrive in fire maintained communities by re-colonizing recently burned areas from adjacent unburned habitat. When the habitat has been decreased to the point that the populations are isolated and small, the lepidoptera can be eliminated if they are entirely consumed by the fire.
Sources of Stress
Thirteen primary sources of stress have been identified. They vary as to their significance which may depend upon which stress they apply to. Some sources were more active historically, such as conversion to agriculture. Others are currently very active sources, such as residential development. In general, the following list is in order of most significant to least significant.
STRATEGIES TO ADDRESS STRESSES
The primary overriding strategy is to focus development away from, and minimize the development of, the highest quality areas of the region. To accomplish this, we will focus our efforts on the areas identified in the Conservation Strategies map, while following the specific strategies listed below. These strategies target the sources of the stresses to the Oak Openings system.
Additional Strategies that apply specifically to the stress; Loss of Habitat. (Source of Stress - Infrastructure-pipelines, utilities and roadways, Pine Plantations and Agriculture)
Additional strategies that apply specifically to the stress; Woody Plant Succession. (Source of stress - Loss of Fire, Groundwater lowering, loss of large ungulates)
Additional strategies that apply to the stress; Groundwater lowering. (Source of Stress - Ditching and tiling, sandmining, ponds, water wells within the perched water table)
Additional strategies that apply to the stress; Exotic Species. (Source of Stress - Planting of exotic species and Colonization by exotic species)
Additional strategies that apply to the stress; Elimination of Native Species. (Source of stress - Insecticide spraying and Fire)
A better understanding of the hydrology is one of the most significant needs for the region. As explained earlier, significant modifications have been made to groundwater levels throughout the region. However, high quality wet prairie habitat remains. How has the lowering affected these remnants? What will additional modifications to existing ditches do to these surviving patches? What effect do sand mines have on the surrounding vegetation? Can ditches be filled or rerouted to improve groundwater conditions without affecting neighboring landowners?
Inventory of Remaining High Quality Areas
Although the ODNR-DNAP maintains a database of element occurrences within the region, most of these records occur from areas within existing parks and preserves. Additional inventory work to identify high quality areas should be performed. The Conservancy's efforts to preserve habitat can be maximized if we are able to focus on the best areas. Our non-traditional partners (i.e. township officials, planners, etc.) will be more empowered if we can supply them with information that identifies the most significant areas. With this information, they may then work to conserve habitat through zoning and conservation development incentives.
Kitty Todd Preserve Inventory and Monitoring
New parcels that are added to the preserve need to be surveyed for rare species. Although the quality of the vegetation is evaluated before purchase, this does not qualify as an overall vegetative survey. Basic survey work should be ongoing as the purchase of land dictates. The collection of baseline pre and post-management data must also occur on an ongoing as needed basis.
A significant amount of work has been performed on rare plants of the Oak Openings. However, far less attention has been focused on rare insects. Although some research has been conducted on the Lepidoptera, there is still much that we do not understand concerning specific requirements that these animals need to survive. The fact that there are more rare butterflies and moths in the region than any other location in Ohio indicates how important the region is for these animals.
Several other insects have been identified as being unusual or of special concern. Two examples are the grizzled ground cricket (Allonemobius griseus) and the sand locust (Psinidia fenestralis) which have been identified in the region but little else is known about them.
The Conservancy should continue to support research that focuses on rare insects of the region.
Grassland and Savanna Birds
Little formal research has been performed on the birds of the Kitty Todd Preserve. The lark sparrow (Chondestes grammacus) is a state endangered (G5, S1) grassland bird known to nest on the preserve. Although some nesting research has been performed on this bird, numerous other grassland and "savanna" birds utilize the preserve and the region. More research is needed to update breeding and migratory bird populations on the Kitty Todd Preserve.
Recent confirmed sightings (1994) of badgers in the Oak Openings Preserve Metropark indicate that this mammal is breeding within the region. Typically described as a prairie animal, the role that badgers might play within the Oak Openings ecosystem is unknown. Further study of the extent of the population within the region is warranted.
LONG TERM VISION/DEFINITION OF SUCCESS
If we successfully implement this plan, conservation within the Oak Openings Region will improve in numerous significant ways. We will have established the finest, most diverse protected site within the region, the Kitty Todd Preserve. This will be the only protected site within the region that harbors a full spectrum of high quality Oak Openings communities ranging from the driest oak savanna to some of the wettest wet prairie.
Our partners will have fully protected other areas of significant habitat. Having achieved this, we will have protected the majority of what remains of the highest quality habitat in the region. We will also have established a core of protected areas that extends from Maumee State Forest to Secor Metropark.
Commercial and residential development projects will be designed to permit the surrounding natural vegetation to persist in fairly contiguous patches. These projects will likely result from a few initial demonstrations, but will then develop on their own because of their financial viability. Development projects that occur on properties without existing quality vegetation will utilize native seed and plants obtained from a locally established native plant nursery.
The Oak Openings region, and its biological significance, will have become well known and understood by citizens of the area. Local citizens group will have formed to promote the conservation of the area. Those who own land within the region will work to protect and promote what oak savanna and wet prairie they may have on their own property. Instead of large areas of turf lawn, the norm will be small areas of yard surrounded by a natural setting of oak savanna or prairie. Citizens of the area will encourage their governments to save habitat, not just because it is biologically significant, but because of its recognized economic value (i.e. increased property values, etc.).
Public and quasi-public institutions that are not normally associated with conservation activities (schools, railroads, pipelines, recreational parks, road rights-of-way) will be participating in a regional effort to conserve habitat by protecting any significant areas that occur on their respective properties.
Each preserve or park that is part of the protected core area of the region will be well equipped and motivated to manage their properties for the full range of species that comprise the globally rare communities of the region.
KITTY TODD PRESERVE MANAGEMENT NEEDS AND OBJECTIVES
The overriding management need for the Kitty Todd Preserve, and the Oak Openings Region as a whole, is the removal of excessive woody vegetation. The objective is to reestablish a balance between the distribution and density of trees, shrubs, grasses and forbs. As a result of fire suppression and groundwater lowering, this balance has been tipped in the favor of woody plants.
Two different historical land use patterns have created two distinctive vegetative conditions on the preserve. The first consists of former agricultural areas and constitutes about 1/3 of the preserve's 400 acres. Most of these areas have succeeded into secondary prairies or savannas. Large trees, especially oaks, are lacking. Depending on the site, succession by smaller aspen, red maple, green ash, black cherry and sassafras is prevalent. Even though selected herbaceous species can be conspicuously absent, these sites generally have healthy populations of grasses, sedges and forbs. The only areas on the preserve with open blowing sand are found in these old agricultural areas, presumably because of past human disturbances to the soil. These sandy areas can be important areas of habitat for several species of plants and animals.
General management needs for secondary savannas and prairies in order of priority:
Most of the remaining portions of the preserve consist of land that has experienced little human modification other than changes in the natural process of fire and water fluctuations. These areas are primary prairie and savanna communities that have become overgrown with trees and shrubs. Some areas are heavily forested with large trees (greater than 6 inch dbh). If a continuous canopy has not yet formed, prairie/savanna grasses and forbs will usually persist in a depauperate state. A dense canopy over extended periods of time will eliminate many understory savanna/prairie species. Exotic species are generally not a problem, although the wet prairie sites are an exception to this. Approximately 2/3 of the preserve is currently in this condition.
General management needs for primary savanna and prairies in order of priority:
Brewer, Lawrence G., John L. Vankat and John L. Walser, The Vegetation of the Oak Openings of Northwest Ohio at the Time of Euro-American Settlement, Department of Botany, Miami University, Oxford, Ohio 3D/Environmental Services, Inc., Cincinnati, Ohio 1993.
Campbell, Lou, Birds of the Toledo Area, The Toledo Blade Company, Toledo, Ohio 1968.
Forsyth, Jane, Kitty Todd: Topography, Geology, Hydrology, and Soils, 1993.
Frost, Pamela Ann, Evaluating the Potential for Preservation of the Oak Openings in Northwestern Ohio Using Geographic Information Systems, Masters Thesis, The Ohio State University, Columbus, Ohio, 1994.
Gordon, Robert B., The Natural Vegetation of Ohio in Pioneer Days, The Ohio State University, Columbus, Ohio, 1969.
He, Jian, Don Larrick and Edward Simmons, Ohio County Indicators, Ohio Department of Development, Office of Strategic Research, Columbus, Ohio, 1994.
Mayfield, Harold, "The Changes in the Natural History of the Toledo Region Since the Coming of the White Man," published with the authors permission by the Metropolitan Park District of the Toledo Area, September, 1976, reprinted from The Jack Pine Warbler, Vol. 40 No. 2 and The Northwest Ohio Quarterly, Vol. 34.
Moseley, Edwin L., Flora of the Oak Openings, The Ohio Academy of Science, Volume VIII, Part 3, Special Paper, No. 20, Bowling Green, Ohio, 1928.