Historic, Archive Document Do not assume content reflects current scientific knowledge, policies, or practices. "i ‘ ae| Ri V Ai eK va rt a Cena ii e a January, 2006 Vol. 45, No. 1 THE MICHIGA A Journal of Great Lakes Botany THE MICHIGAN BOTANIST (ISSN 0026-203X) is published four times per year by the Michigan Botanical Club (www.michbotclub.org). The subscription rate is $20.00 per year. Periodicals postage paid at Ann Arbor, MI 48103. The office of publication is Andrews University, Berrien Springs, MI 49104. On all editorial matters, please contact Todd J. Barkman, 3437 Wood Hall, Department of Biologi- cal Sciences, Western Michigan University, Kalamazoo, MI 49008; 269. 387. 5610 or 269. 387. 2776 (Phone), 269. 387. 5609 (FAX); [email protected]. All articles dealing with botany in the Great Lakes region may be sent to the Editor at the above address. In preparing manuscripts, authors are requested to follow the “Instructions for Authors” on the inside back cover. For all inquiries about back issues and institutional subscriptions please contact Linda Reece, The Michigan Botanist Business Office, Andrews University, Biology Department—216 Price Hall, Berrien Springs, MI 49104; 269. 471. 3243 (Phone), 269. 471. 6911 (FAX); reecel@ andrews.edu. Editorial Board Todd J. Barkman, Editor Linda Reece, Business Manager L. Alan Prather Sarah E. Todd Anton A. Reznicek Edward G. Voss J. Dan Skean, Jr. Catherine H. Yansa THE MICHIGAN BOTANICAL CLUB Membership is open to anyone interested in its aims: conservation of all native plants; education of the public to appreciate and preserve plant life; sponsorship of research and publication on the plant life of the state and the Great Lakes area in general, both in the USA and in Canada; spon- sorship of legislation to promote the preservation of Michigan’s native flora; establishment of suitable sanctuaries and natural areas, and cooperation in programs concerned with the wise use and conservation of all natural resources and scenic features. Dues are modest, but vary slightly among the chapters. To become a chapter member please contact the chapter presidents listed below. “Special Members” (not affiliated with a chapter) may send US$21 to Irene Eiseman, MBC Special Membership Chairperson, 1873 Pierce Road, Chelsea, MI 48118, 734. 475. 9654. For both classes of membership, annual dues include a subscription to The Michigan Botanist. Address changes for Chapter Members should go to the Chapter Pres- ident; address changes for Special Members should go to Irene Eiseman. President: Pamela Laureto, Biological Sciences Department, Grand Rapids Community College, 143 Bostwick Avenue NE, Grand Rapids, MI 49503; plaureto@ grcc.cc.mi.us; [email protected] Treasurer: David Steen, Biology Department, Andrews University, Berrien Springs, MI 49104; steen @andrews.edu Huron Valley Chapter: Larry Nooden, Biology Department, University of Michigan, Ann Arbor, MI 48109; ldnum @umich.edu Red Cedar Chapter: Megan Daniels, 7618 Briarbrook Drive #1B, Lansing, MI 48917; daniel48@ msu.edu Southeastern Chapter: Emily A. Nietering, 231 Nash Street, Dearborn, MI 48124-1039; knietering@ worldnet.att.net Southwestern Chapter: Dennis Woodland, Biology Department, Andrews University, Berrien Springs, MI 49104; woody @andrews.edu White Pine Chapter: Dorothy Sibley, 7951 Walnut Avenue, Newaygo, MI 49337; dsibley @mail. riverview.net 2006 THE MICHIGAN BOTANIST 1 VASCULAR PLANT STUDY OF WARREN DUNES STATE PARK, BERRIEN COUNTY, MICHIGAN Pamela F. Smith! and Dennis W. Woodland (woody @andrews.edu) Andrews University Biology Department Berrien Springs, MI 49104 ABSTRACT A botanical survey was conducted to document the plant biodiversity of Warren Dunes State Park (WDSP), located in Lake Township, Berrien County, Michigan. The park consists of 4 km of shore- line and 789 hectares of forested dunes and wetland areas. This information was generated to provide baseline floristic data for WDSP, one of Michigan’s most visited state parks, which has not been in- ventoried as a unit. A documented list of vascular plants was compiled based on over 1,200 samples collected between June 10, 2004 to November 06, 2005. Thirty-three taxa reported and/or docu- mented by other researchers to be present at WDSP that were not collected during this survey were also included on the vascular plant list. The resulting vascular plant list contains 725 taxa (712 species, 8 hybrids, 4 varieties and 1 subspecies). Of these taxa 76% are native and include 8 state- listed threatened species, 2 state-listed special concern and 1 federally listed plant species. Based on comparisons with other Michigan public parks, these results indicate that WDSP is botanically di- verse and a refuge for rare species. KEY WORDS Berrien County, Biodiversity, Michigan, Vascular Plant, Warren Dunes State Park INTRODUCTION Michigan State Parks serve as sanctuaries that protect significant biodiversity. Warren Dunes State Park (WDSP) is a prime example because it contains a high diversity of vascular plant species, including eight state-listed threatened species, two state-listed special concern species, and one federally listed threat- ened species (Kost et al. 2002). According to the Michigan Natural Features In- ventory (MNFI), rare animal species have been also documented in the park, in- cluding the state-listed endangered prairie warbler. Significant geographic features found at WDSP according to the MNFI include the mesic northern for- est community, open dunes, interdunal wetlands, and unperched dunes (Kost et al. 2002). There were several studies conducted previously at WDSP. The northern quarter of the park, which is often referred to as the Mount Edward tract, was | Present address: 4824 Overhill Drive, Ft. Collins, CO 80525 pamelas4824 @earthlink.net. 2 THE MICHIGAN BOTANIST Vol. 45 surveyed by Wagner (1979), and Wells and Thompson (1982). Kost et al. (2002) conducted an inventory for significant natural features of the park. Invasive plant species have been inventoried by the State of Michigan (Schneider & Mindell 2003) and control methods are presently being implemented (Palmgren 2004). Although these studies have been conducted and others are underway, the entire park had not been systematically inventoried botanically. The goal of this study, which is part of a more comprehensive study con- ducted by Smith (2006), was to provide baseline information to document the floristic biodiversity of WDSP. This information is important because an exotic species control plan has been initiated by the State of Michigan, which included mapping the invasive species but not the native plants or locations for the rare taxa. A floristic list, based on approximately 1201 dried herbarium specimens, 8 photographs collected during this study and reports of 33 species by MDNR and botanical researchers is provided in this report. Qualitative descriptions are in- cluded for the major plant communities at WDSP, in addition to brief discussions of the geology, soils, topography and human history. This information is valuable as a management tool given that WDSP, like so many of our natural areas, is facing a myriad of assaults on biodiversity. Many of these assaults are the result of anthropogenic forces, including pollution, overdevelopment, invasive species, fire suppression, erosion, and excessive deer populations (Kost et al. 2002). Land Administration A significant portion of this park is not owned directly by the State of Michi- gan, but is under a lease agreement that will lapse in 31 years (2037). The organi- zation holding this property, the E. K. Warren Foundation, is in contact with the State of Michigan regarding the future ownership of this land. The original agree- ment states that the lands leased to WDSP are to be preserved in “perpetuity, in their primeval state for students and lovers of nature” according to Peg Kohring (personal communication, September 07, 2004). Ms. Kohring is the Midwest Di- rector of the Conservation Fund, and represents the organization that is negotiating the E. K. Warren Foundation lease agreement. A large portion of the park is also designated as a state Natural Area and includes much of the land leased from the E. K. Warren Foundation. As this is being written, the northern section of the park is under consideration for designation as a new state Natural Area (Phyllis Hig- man, Michigan Natural Features Inventory, personal communication, November 30, 2005). Natural Areas are legal designations currently under the jurisdiction of the Michigan Department of Natural Resources under the Wilderness Act of 1972. Natural Area designations came about after it became clear that State Park desig- nations did not protect areas from mining, logging and other consumptive uses. In the past, recommendations were made to State Parks by organizations including the Michigan Natural Areas Council, Michigan Natural Resources Commission, Natural Areas Advisory Board and Michigan Natural Features Inventory, as to which areas were worthy of designation. According to the most recent information provided by MDNR, no new Natural Area dedications have occurred since 1988 (Michigan Department of Natural Resources 2006a). e2006 eTHE MICHIGAeN BOTANIST a * Bridgman n | - Lake Street MICHIGAN Browntown Road * S awyer km Lake Township Berrien County, Michigan FIGURE 1. Location map of Warren Dunes State Park in Lake Township, Berrien County, Michigan. Location WDSP is located on the shore of Lake Michigan in the west central portion of Berrien County, just south of the town of Bridgman and north of the town of Sawyer, Michigan, T6S; R.20W; Sec. 24-26, 35-36 (Figure 1). The park covers 789 hectares (1,950 acres) of forested dunes, open beach, and a variety of wet- land habitats. The southern boundary is Browntown Road, and the northern boundary is located south of Lake Street. The park is bounded on the west by Lake Michigan and on the east largely by Red Arrow Highway. The location of WDSP, with the proximity to Lake Michigan, and deep valleys formed by an- cient dunes, provides a range of habitats and microclimates that support a di- verse assemblage of plants. Climate The location of WDSP on the shore of Lake Michigan has a significant effect on the vegetation. The moderating effect of the lake reduces fluctuations in at- mospheric temperatures compared to inland areas. Frosts occur later in the fall, while the spring temperatures tend to be cooler than they are in more inland areas. Michigan State University Extension reports that the moderated tempera- tures are the reason Berrien County has more fruit farms and more cold sensitive crops than any other county in Michigan (Anonymous 2005a). The moderate cli- mate near Lake Michigan, which allows for successful fruit crops in the vicinity of the park, may explain why plants and plant associations typical of the north- 4 THE MICHIGAN BOTANIST Vol. 45 ern part of the state (for example, the mesic northern forest community) can be found at WDSP, while they are not found in areas that are inland at the same lat- itude. In addition, plants typical of more southern areas can be found near the Lake Michigan shoreline in Berrien County, as a result of the moderate climate. Wells and Thompson (1982) provide a detailed discussion of the climatic condi- tions of this region. The most recent summary reported by the National Oceanic & Atmospheric Administration (NOAA) weather station at Benton Harbor showed an average minimum temperature in January of —8°C (18 F) and an average maximum tem- perature in July of 28°C (82° F). The growing season was 162 days for 2005. The average annual rainfall was reported as 94 cm (37 in), with an average an- nual snowfall of 178 cm (70 in) (NOAA Benton Harbor Climate Summary posted in 2005). Soils The soils of Warren Dunes State Park (WDSP) include a total of eleven soil types that occur within two major soil associations. The two soil associations are the Spinks-Oakville-Oshtemo, and the Morocco-Thetford-Granby Associations, according to the Soil Survey of Berrien County (Larson 1980). The Spinks- Oakville-Oshtemo Association includes level to very steep, well-drained sandy and loamy soils. This association characterizes the western portion of the park, and includes much of the forested dune area and actively shifting dunes. The Morocco-Thetford-Granby Association is found on level, poorly drained sandy soils (Larson 1980) that are common on the eastern edge of WDSP. These soils support lowland hardwood, wetland shrub and swamp habitats. The two most common soil types within WDSP are in the Spinks-Oakville- Oshtemo Association and include the dune land soil and the Oakville fine sand soils with 18 to 45% slopes. The dune land soils are found in the blowouts, and include the actively shifting sands higher in elevation than the beach area. The dune land soils support beach grasses, as well as a characteristic set of shrubs and trees. The soil type characteristic of the forested dune area of the park is Oakville fine sand. Although a few small areas in this soil type have slopes from 0 to 18%, the majority of the soil slopes are steep to very steep with 18 to 45% slopes, and include slopes in excess of 45%. The Oakville fine sand soils also contain a small percentage (2 to 4%) of shallow depressions of poorly drained Morocco soils (Larson 1980). A number of different wetland soil types common in the Morocco-Thetford- Granby Association are found at WDSP. The large wetland area near Floral Lane is largely comprised of Houghton muck soil, which is a poorly drained soil, often with standing water. The wetland area near the eastern edge of Mount Randal is characterized by Gilford sandy loam. This soil is level, very poorly drained and typically has standing water, as the water table may vary from 15 cm above to 30 cm below the water table for this soil type (Larson 1980). The wetlands located in the northern section of the park, near the I-94 interchange, are characterized by ponded aquents and histosols. According to Larson (1980), these level soils are found in depressed areas along tributaries of rivers that flow into Lake 2006 THE MICHIGAN BOTANIST 5 Michigan, as well as wet areas along the shores of lakes. These soils are charac- terized by standing water that is typically present year round. The I-94 wetland area is currently a shrub-dominated community, with marsh vegetation towards the center. However, the north wetland was a lake until quite recently. A map provided by Kost et al. (2002) of the vegetation of Michigan circa 1800, and the United States Geological Survey topographic map of the Bridgman quadrangle from 1971, show this area as a lake. The southernmost wetland near the I-94 in- terchange consisted of aquents and histosols in addition to Granby loamy fine sand. These are level, poorly drained lowlands that are subject to frequent stand- ing water and have a strongly acidic surface layer. This soil type can also be en- countered on knolls and ridges according to Larson (1980). It is frequent along the eastern edge of the park. Geology The forces that shaped the landscape today at WDSP were associated with glaciation. The last advance of glacial ice into this area is known as the Wiscon- sinan stage. Approximately 11,000 years ago the most recent glacier retreated from the Michigan area (Dorr & Eschman 1970). The tremendous scouring caused by the movement of massive ice sheets, which may have reached greater than a mile in thickness during glacial stages, and the debris they brought with them, provided tremendous forces that created the Great Lakes and many topo- graphic features. The meltwaters, the lowering of lake outlets, and the post glacial rebound of land resulted in fluctuations of lake water levels that were fan- tastic compared to today’s standards. Lake levels over 60 m (200 feet) higher than those presently encountered (Dorr & Eschman 1970) occurred during post- glacial pre-historic times. The lake level fluctuations that have been recorded in recent history only amount to changes in average lake levels of up to 2.4 m (8 feet), according to data from the Army Corps of Engineers Lake Michigan lake level data (Anonymous 2005b). The major events that formed the dunes at WDSP (and the east shore of Lake Michigan, in general) occurred when lake levels were about 7.6 m (25 ft) higher than at present. Lake Algonquin and Lake Nipissing are two stages of the ances- tral Great Lakes that were associated with two major dune-building events, the first of which occurred 13,000 years ago while the northern part of the state was still glaciated. According to Tague (1946), Lake Algonquin was the greatest of all the ancestral Great Lakes, and combined the area where we find Lakes Michi- gan, Superior and Huron. The dunes that formed during the Algonquin stage in- clude the oldest and most uncommon (and typically the furthest inland) dune type at WDSP. These are the easternmost dune ridges and formed when the lake level was approximately 7.6 m (25 feet) higher than the present level (Wells & Thompson 1982). The second major dune-building period during the Lake Nipissing stage also occurred when the lake level was approximately 4.6 to 7.6 m (15 to 25 feet) higher than the present time (Dorr & Eschman 1970). This period, during which the majority of the sand dunes at WDSP formed, occurred approximately 4,000 to 6,000 years ago (Albert 2000). The lake fluctuated to levels both higher and 6 THE MICHIGAN BOTANIST Vol. 45 lower than those typical of present day, between the Lake Algonquin and Lake Nipissing stages. According to Albert (2000), dune growth is perpetuated by higher lake levels because erosion increases and more sand is available than when lake levels are lower. Tower Hill, located in the southern part of WDSP near the parking area, was given by Dorr and Eschman (1970) as an example of a large dune that formed during the Lake Nipissing stage. They noted the very steep windward face of Tower Hill was a blowout, which “has resulted from the reactivation of an ancient sand dune” (Dorr & Eschman 1970, p. 201). The Algoma stage was a recent lake level intermediate between the Nipissing level and the present day lake level. Algoma ridges reached 180 meters (590 feet) above sea level (Tague 1946). These include the forested dune ridges lo- cated closest to the shore of Lake Michigan. High dunes and low dunes represent two major types of coastal dunes at WDSP. The foredune ridges are low dunes and range from 9-15 m high, and are close to the beach. High dunes are over 30 m tall and are located behind the fore- dunes. These tall dunes are typically stabilized with forest growth and are much older (Dorr & Eschman 1970). Forested dune areas make up the majority of the forested land at WDSP. When the high dunes become eroded they form blowouts, and these modify the original dune ridges into irregular serpentine shapes. Sand mining has been a prominent land use in southwest Michigan. Two areas have been mined in the past at WDSP. The sand found in the coastal dunes of southern Michigan is prized because of the high quartz content. One of the sand mined areas was located in the central area of the park and another was lo- cated in the northern section. Both of these areas appear to be much less biodi- verse and have a greater number of non-native species than areas that were not subject to mining. Topography The older dune ridges that form the base for the forested dunes have resulted in a complex topography including valleys, flat lowlands, and mildly sloping to very steep slopes in excess of 45% (Larson 1980). Elevations at WDSP range from lake level, which averaged 176 m (577 feet) in September 2005 (Anony- mous 2005b), to over 238 m (780 feet) above sea level at the summits of Mount Edward, Mount Randal, and Mount Fuller. The range of habitats formed by the steep topography, offering a variety of slopes and directional slope facings, mixed with a matrix of wetland and well-drained soils, found both in lowlands and on ridges and knolls, provide an amazing array of habitats that contribute to the biodiversity of WDSP. Human History The vegetation that exists today at WDSP is a result of a complex interaction between natural and human history. The earliest European explorers were known to have visited this area from 1673 to 1763, while the region was under French rule. Steamships began to appear on the Great Lakes in the early 1800s, and the