A Floristic Survey of the Terrestrial Vascular Plants

A FLORISTIC SURVEY OF THE TERRESTRIAL VASCULAR PLANTS

OF STROUDS RUN STATE PARK, ATHENS COUNTY, OHIO

A thesis presented to

the faculty of

the College of Arts and Sciences of Ohio University

In partial fulfillment

of the requirements for the degree

Master of Science

Sarah M. Harrelson

A FLORISTIC SURVEY OF THE TERRESTRIAL VASCULAR PLANTS

OF STROUDS RUN STATE PARK, ATHENS COUNTY, OHIO

BY SARAH M. HARRELSON

has been approved for

the Program of Environmental Studies

and the College of Arts and Sciences by

Philip D. Cantino

Professor of Environmental and Plant Biology

Leslie A. Flemming

Dean, College of Arts and Sciences HARRELSON, SARAH M. M.S. March 2005. Program of Environmental

Studies

Floristic Survey of the Terrestrial Vascular Flora of Strouds Run State Park,

Athens County, Ohio. (195pp.)

Director of thesis: Philip D. Cantino

This study documented the terrestrial vascular flora of Strouds Run

State Park (SRSP) in Athens Co., Ohio, and compared it with an earlier flora

of the same area completed in 1957. Differences in the species composition

of the herb layer between mixed mesic and oak forest and between differently

aged stands were analyzed using NMS ordination. Over the course of two

growing seasons (2003 and 2004), 624 species in 106 families were found in

SRSP. The number and abundance of invasive species increased since 1957,

but the percentage of species that are exotic decreased. The abundance of

some ant-dispersed species increased, some decreased, and some remained

the same. The abundance of most medicinal herb species has changed little

since 1957, with the exception of goldenseal (Hydrastis canadensis), which

has greatly increased. An NMS ordination of the herb-layer species

composition of plots showed a clear separation between mesic and oak forest,

and between young and old stands. Separation between mesic and oak forest

may be due to moisture differences; however, soil moisture was not measured

in this study. A significant difference (p < 0.05) in litter accumulation and the amount of canopy cover may explain the separation of old and young stands in mesic forests, but the age separation in oak forests was not explained by the results of this study.

Approved by:

Philip D. Cantino

Professor of Environmental and Plant Biology Acknowledgements

I would like to thank Bob Eichenberg of the Athens County Regional

Planning Commission for the preparation of topographic maps of Strouds Run

State Park, which were used extensively in my field work. Philip D. Cantino,

John Knouse, and Chris Haufler (University of Kansas) helped with some species identifications. Glenn Matlack helped with analyzing statistical data, and Jennifer Gray and Jim Dyer helped produce the maps that are included in this thesis. Finally I thank Cynara M. Medina for editorial comments and technical assistance. I could not have done it without you!

Table of Contents

Abstract ...... 4

Acknowledgements ...... 6

List of Tables ...... 9

List of Figures...... 11

Chapter I Introduction ...... 13

Chapter II The Floristic Survey ...... 17 Introduction...... 17 Study Area...... 18 History of Strouds Run State Park...... 18 Description of the Study Area...... 20 Methods...... 23 Results and Discussion ...... 27 Overall Summary...... 27 Community Types...... 28 Unusual Habitats ...... 36 Potentially Threatened Species ...... 40 Comparison of the 1957 Flora with the Current Flora of Strouds Run State Park...... 44

Chapter III Invasive Species in Strouds Run State Park...... 50 Introduction...... 50 Methods...... 53 Results and Discussion ...... 54 Management Implications...... 79

Chapter IV Changes in Abundance of Ant-Dispersed Forest Herbs in Strouds Run State Park ...... 81 Introduction...... 81 Methods...... 83 Results and Discussion ...... 83

Chapter V Status of Medicinal Herb Populations in Strouds Run State Park .... 92 Introduction...... 92 Methods...... 97 Results and Discussion ...... 97 8

Chapter VI Influence of Stand Age and Environmental Factors on Herbaceous Species Composition...... 104 Introduction...... 104 Materials and Methods ...... 107 Field sampling ...... 107 Data analysis...... 109 Results ...... 111 Discussion ...... 129 Conclusion...... 133

Literature Cited...... 135

Appendix 1: Terrestrial vascular plant species documented at Strouds Run State Park, Athens County, Ohio ...... 159

List of Tables

Table 1. The collecting schedule for the 2003 floristic survey of SRSP...... 25

Table 2. The scale of abundance as used by Payne (1957)...... 26

Table 6. The abundance of invasive species in 1957 and their current abundance within SRSP, Athens, Ohio...... 54

Table 7. The abundance of ant-dispersed forest herbs in 1957 and theircurrent abundance within SRSP, Athens, Ohio...... 84

Table 8. The abundance of medicinal herbs in 1957 and their current abundance within SRSP, Athens, Ohio...... 98

Table 10. Mean measurements of litter cover, litter depth, canopy cover, species richness, and species cover for each sampling season in five community types in SRSP. Significant differences are indicated by the letters following each measurement. Items with different letters are significantly different (p < 0.05) from each other. Statistical analysis was across communities within a season; letters are compared within columns, unlike Table 9...... 113

Table 12. Species that were significantly correlated (p < 0.05) to at least one of the Axes in one of the four ordinations performed, and had an r value ≥ 0.5...... 115

Table 13. Correlations of the measured environmental variables with the first three Axes for each NMS ordination...... 116

List of Figures

Figure 1. Map of Ohio, showing the location of the city of Athens...... 20

Figure 2. Map of Strouds Run State Park...... 21

Figure 3. Map of SRSP, showing the location of the marshes around Dow Lake and the old field communities...... 29

Figure 4. Map of the northern portion of SRSP, showing the location of the beaver ponds and the marshes around them, and the location of the largest population of Huperzia lucidula found during the study...... 32

Figure 5. Map of the eastern portion of SRSP, showing the location of the three prairie-like openings discovered during the study...... 38

Figure 6. Map of the southwest portion of SRSP, showing the approximate locations of two of the potentially threatened taxa found during this study. .. 41

Figure 7. Map of SRSP showing the approximate location of three of the potentially threatened species found during the study. The location of Corallorhiza wisteriana was mapped with a GPS unit...... 42

Figure 8. Map of the southwest corner of SRSP showing Blue Ash Valley...... 46

Figure 9. Map of SRSP showing the approximate locations of the largest populations of Asian stilt grass and garlic mustard. Size of polygon does not indicate size of population...... 68

Figure 10. Map of SRSP showing the approximate location of the largest populations of tree of heaven, Asian stilt grass, and Japanese knotweed. Size of polygon does not indicate size of population...... 72

Figure 11. Map of SRSP showing the approximate location of a population of tree of heaven. Size of polygon does not indicate size of population...... 75

Figure 12. Map of SRSP showing the location of areas with very large trees. ... 86

Figure 13. Map of SRSP showing the location of areas with very large trees and a rich understory...... 87

Figure 14. NMS ordination of the greatest amount of cover recorded for each species encountered at each of 35 plots in the SRSP study. Note the separation of three community types; age differences are not shown...... 120 12

Figure 15. NMS ordination as in Figure 14, with pine plantations removed and showing differently aged mesic and oak plots. Plots on slopes are not shown...... 121

Figure 16. NMS ordination of the amount of cover recorded for each species at each plot during the May survey of community types in SRSP. Differently aged plots are not distinguished...... 122

Figure 17. NMS ordination of the mount of cover recorded for each species at each plot during the July survey of community types in SRSP. Differently aged plots are not shown...... 123

Figure 18. NMS ordination of the amount of cover recorded for each species at each plot during the September survey of community types in SRSP. Differently aged plots are not distinguished...... 124

Figure 19. Dendrogram produced from the cluster analysis of the species composition of 35 plots sample in SRSP. The community type for each plot is written underneath each plot number; the 25% mark was used as the cutoff to define groups...... 125

Figure 20. NMS ordination as in Figure 14, with groups from the cluster analysis depicted. Differently aged plots are not distinguished...... 126

Figure 21. NMS ordination as in Figure 14, after north or south-facing plots were re-assigned as young or old plots; pine plantations are not shown. Plot 2, 17, and 33 did not sort out as expected...... 127

Figure 22. NMS ordination as in Figure 14, depicting plots on slopes. Note how the sloped plots do not group with each other. Differently aged plots are not distinguished...... 128

Figure 23. NMS ordination as in Figure 14, depicting pine plantations and old mesic stands...... 132

Chapter I

Introduction

Floras, or inventories of plants found growing in a defined area (Palmer et

al. 1995), yield large amounts of valuable data to the scientific community. An

initial review of the literature conducted by Palmer et al. (1995) revealed

approximately 8,000 published floras for areas of North America north of Mexico.

They estimated that at least 4,000,000 person hours have been invested in

floristic research. These activities have produced data for the study of changes

in species distribution (Gauch and Stone 1979, Moreno-Casasola 1988, Brothers

1994), the effect of habitat fragmentation on species composition and diversity

(Jules 1998, Bruun 2000, Harrison et al. 2000), species loss and invasions

(Pysek and Prach 1993, Robinson et al. 1994, Fischer and Stocklin 1997), the success of ecological restoration attempts (Purata 1986, Thompson and Wade

1991, Galatowitsch and van der Valk 1996), and phytogeographic patterns

(Pavlik 1989, Ojeda et al. 1998). The practical relevance of floristic data should not be overlooked as it provides important information for ecologists and land managers who are interested in the study of floristic change over time for conservation purposes. Awareness of species composition changes through time allows for an improved understanding of current species assemblages and may provide meaningful clues for the preservation of unique communities (Birks et al. 1988, Foster 1992). 14

Floristic data are also important for the study of diversity and species abundance. Peterken and Game (1984), for example, examined the effects of past disturbances on the abundance and distribution of woodland species. They found that recent woods (originating since 1820) that are the most isolated from ancient woods (originating prior to 1610) have fewer species than recent woods that are the least isolated. They also showed that initial colonization of recent woods is rapid, followed by a later, slow phase of species accumulation, and that the amount of isolation only affects the slow phase of colonization. Drayton and

Primack (1996) conducted a floristic survey of an urban woodland area near

Boston and compared it with a survey of the same woodland published in 1894 to determine how the flora had changed over the last 100 years. They found that

38% of the original native species and 31% of the exotic species were lost.

Native species disappeared at a rate of 0.48% per year.

In spite of the enormous amount of information encompassed by floristic data, Prather et al. (2004) have identified an alarming trend of decline in the collecting of herbarium specimens. They cite numerous erroneous assumptions in the scientific community that underlie this trend: 1) the flora of North America, especially that of the U.S., has already been adequately described, and little else can be learned from continued collecting and floristic work; 2) consolidation or even elimination of existing herbarium collections would have no detrimental effects; 3) the creation of online databases or the use of digital images should replace instead of supplement actual herbarium specimens; 4) taxonomy and 15

descriptive floristics are not experimental science and therefore are not worthy of

pursuit; 5) floristics and taxonomy should only exist to provide information for

other scientific endeavors; and 6) the cost of maintaining herbarium collections

outweighs the benefits they can provide.

However, these arguments do not take into account issues like

conservation and preservation of diversity cited above. In addition, other equally

important considerations support the continuation of herbarium collecting and

floristic work (Muhlenbach 1979, Prather et al. 2004). For example, our knowledge of the current flora will repeatedly become outdated unless floristic data and voucher specimens continue to be collected over time. Also, there are large areas of the U.S. (southeastern and western) where the flora is still not accurately described. Finally, because of the numerous threats to native species, it is imperative that the cataloging of local flora continues indefinitely.

The objectives of this study, each of which is addressed in a separate chaper, were the following:

• To complete a floristic inventory of Strouds Run State Park

• To determine whether invasive species have become established in the

park since an earlier flora of the area that was completed in 1957 and

whether the abundance of those that were present at that time has

changed.

• To determine whether there are any state- listed endangered,

threatened, or potentially threatened species present in the park. 16

• To determine which species of ant-dispersed native forest herbs are

present in the park, where they tend to be located, and how much the

abundance of these species has changed since 1957.

• To determine which of the medicinal herb species facing collecting

pressure in Ohio are present in the park and whether their abundance is

changing.

• To determine if there is a difference in species composition between

ridge tops and stream bottoms, between north-facing and southwest-

facing slopes, and between old and young woods.

Chapter II

The Floristic Survey

Introduction

Although many floristic surveys have been published, very few document floristic change. An exception is the survey of Waterloo Wildlife Research

Station (WWRS) conducted by Small and McCarthy in 2001. This area had already been surveyed in 1954 (Price 1955). Small and McCarthy added 241 species to the flora of WWRS, but the percentage of species that are native—

83% in 1996, 80% in 1954—remained essentially the same.

The present study will examine change over time by using the flora of

Athens State Forest, documented by Willard Payne in 1957, as a reference point and comparing Payne’s findings with the results of a new survey of the same area, now designated as Strouds Run State Park (SRSP). Through this comparison, questions concerning changes in the floristic composition of the area and their implications for future park management, scientific research, and species protection can be explored. The data generated can be used to address questions of practical concern such as whether the number and abundance of invasive species within SRSP has increased since 1957, and whether changes in abundance of medicinal herbs indicate that they are being collected from the park. 18

Study Area

History of Strouds Run State Park

Athens County was settled in 1794 after General Wayne defeated the

Shawnee and Delaware tribes. Farmers settled the rich bottomlands of Canaan

Township in 1797 and supplemented their income through the exploitation of coal

and salt mines that were still profitable at the time (Payne 1957). The park and

its principal stream derive their name from the Strouds family, which arrived in the late 1800s (ODNR Strouds Run website). By 1935, improper farming techniques had lowered the value of the land to such an extent that farmers could no longer make a living (Historical Records Survey as cited by Payne,

1957). Farm remnants continue to survive, and several home foundations can still be seen in the park. At the time of Payne’s survey, some fields were still being cut for hay (Payne 1957), but crop farming was no longer practiced by

1939 (based on aerial photos).

In 1940, the farm of Waldo Poston, consisting of 40 ha in section 23 of

Canaan Township, was the first parcel of land purchased for what was then known as Athens State Forest. Several adjoining farms were added to the state forest through the right of eminent domain (Payne, 1957). In 1942 and 1943, the

first plans were developed for the use of the Strouds Run Area by Ohio

University in conjunction with the State Forestry Department. The original

Committee (Dr. C.L. Dow of the Geology Department, Dr. H.T. Gier of the

Zoology Department, Dr. P.E. McClure of the Physics Department, Mr. Edward 19

Rinehart of the Ohio Conservation Department, and Dr. A.H. Blickle of the

Botany Department) had intended to purchase the entire Strouds Run watershed for use as a land laboratory to study soil, water, and wildlife conservation

(McConnell 1963).

After the Committee held two official meetings with legislative groups, it obtained $100,000 in the legislative session of 1946 for the purchase of the

Strouds Run watershed. However, due to a sharp increase in the price of land, only about one half of the drainage area could be acquired. The idea of the establishment of a lake was already included in the original proposal to the legislature, and an additional $100,000 was incorporated in the initial appropriation for its construction (McConnell 1963).

The acquisition of land by the Division of Forestry began in 1946; however, the purpose was to establish a state park rather than a conservation laboratory (McConnell 1963). Between 1948 and 1953, the state bought additional land for conservation purposes (ODNR, Strouds Run website). During the years 1946 to 1960, the Division of Forestry implemented a plantation management program, which consisted of planting pines and hardwoods on the open areas within tracts of land as they were purchased (McConnell 1963). One hundred fifty three hectares were planted, 90% of it in red and white pine, and

10% in Scotch pine, shortleaf pine, larch, black locust and tulip poplar (Payne,

1957). 20

Named in honor of Clarence L. Dow, a professor of Geology and

Geography at Ohio University who was instrumental in initiating the project, Dow

Lake covers approximately 65 ha. The dam creating it was constructed by the

Division of Parks and completed in 1960. At around the same time the Ohio

Department of Natural Resources (ODNR) opened the forest to the public as

SRSP (ODNR, Ohio State Parks pamphlet).

Today, SRSP covers 1055 ha including Dow Lake. It is a popular recreation area, containing large blocks of uninterrupted woodland. People enjoy a wide range of activities here, with 21 km of hiking trails, a beach on Dow Lake, and a camping area. Hunting, fishing and boating are also permitted (ODNR,

Strouds Run website). Classes from Ohio University conduct field trips to the park, and various parts of the park have served as research areas for students.

Description of the Study Area

SRSP is located in Canaan and Ames Township in central Athens County,

Ohio, approximately five to eight km east of the city of Athens (Figures 1 and 2).

Figure 1. Map of Ohio, showing the location of the city of Athens. 21

Figure 2. Map of Strouds Run State Park. 22

The elevation of Athens County ranges from less than 170 to more than

320 m above sea level (Payne 1957). In SRSP, the lowest elevation (193 m

above sea level) is in the southeast corner, at the main entrance off of US 50.

Many ridge tops in the park exceed 270 m, and the highest point in the park is a

312 m hilltop in section 35 of Canaan Township (Athens quadrangle, United

States Geological Survey 1985).

Athens County has a temperate continental climate, experiencing four

distinct seasons. The mean length of the growing season is 143 days (Lucht et

al. 1985). Between 1971 and 2000, the mean annual temperature in Athens

County was 10.72° C, the warmest average temperature was in July (mean =

22.61° C), and the coolest in January (mean = -7.94°C). The average annual precipitation for Athens County between 1971 and 2000 was 100.58 cm (National

Climatic Data Center and National Oceanic and Atmospheric Administration

(NCDC/NOAA) 2004). During 2003, the mean annual temperature in Athens

County was 11° C, with the warmest average temperature in August (mean = 22°

C) and the coolest in January (mean = -5° C) (National Climatic Data Center and

National Oceanic and Atmospheric Administration (NCDC/NOAA) 2004). The annual precipitation for Athens County in 2003 was 123 cm. In 2003, the last day of the spring with freezing temperatures was April 28, and the first day of the fall with freezing temperatures was October 3 (NCDC/NOAA 2004). The nearest weather station to the study area is Ohio University’s Scalia Lab, which is located 23

242 m above sea level, at latitude 39° 19 min. 20 sec. north, and longitude 82° 5

min. 57 sec. west.

Because annual climatic conditions vary from year to year, the presence

and abundance of plant species could vary accordingly. For this reason I include

climatic data from McConnelsville, Ohio (approximately 38 miles northeast of

Athens) for 1956, the year Payne conducted his research: average annual temperature was 10.73°C, warmest average temperature was in July (mean =

22.24°C), and the coolest in January (mean = -3.74°C). The annual precipitation in 1956 was 122.71 cm (United States Historical Climatology Network).

SRSP lies on the Muskingum-Pittsburg Plateau section of the Unglaciated

Allegheny Plateau physiographic province, and the bedrock underlying the park is entirely Pennsylvanian (Ohio Geological Survey website). Pennsylvanian rocks consist of an assortment of sediments, including coal, sandstone, and shale (Sedimentology and Stratigraphy website).

The most common soil type found in SRSP is Westmoreland-Guernsey silt loam, but Upshur-Elba silty clay loam, Steinburg sandy loam, and Guernsey

Upshur complex soil types are also commonly found in this area (Lucht et al.

1985). Limestone outcrops and thin layers of coal can occasionally be seen in the park.

Methods

Before the floristic survey was started, the park was divided subjectively into plant community types to make the most efficient use of field time. 24

Identification of community types was done in the fall/winter of 2002-2003 and was based on visually estimated canopy dominance. Seven common community types were identified: mixed oak woods (including oak-hickory and oak-maple), pine plantations, mesic ravines and stream terraces (mixed mesophytic forest), old fields, marshes and lake edge, young woods (deciduous forest; approximately 30 years since canopy closure), and lawns and regularly mowed areas. In addition, two distinctive but uncommon habitats were identified based on previous knowledge of their existence in the park: rock outcrops and prairie- like openings. Several air photos were used to determine the age of forests in

SRSP; all were at the 1:20,000 scale. The specific reference numbers for each photo are as follows: 1939: BBW-7-15. 1950: BBW-3G-26 and BBW-4G-141.

Collecting was done over two growing seasons, from March 2003 through

September 2004. Exemplars of each community type (three for mixed oak woods and mesic ravines and stream terraces, and two for the five other community types) were chosen for intensive study, while other parts of the park, representing all community types, were walked in search of species not found in the intensively studied exemplar areas. Rocky outcrops and prairie-like openings were also regularly surveyed. To ensure encounters with as many species as possible while they were blooming (and therefore easily identifiable); a collecting schedule (Table 1) was followed. For each species found, the community type and/or habitat where it was observed and its abundance within the park were noted. Overall abundance of each species was estimated using the same scale 25

that Payne (1957) applied (Table 2). After collection, each specimen was dried

and pressed using standard techniques and deposited in the Bartley Herbarium

of Ohio University.

Plants were identified using Braun (1961, 1967), Cooperrider (1995),

Fisher (1988), Flora of North America (FNA 1993), Gleason and Cronquist

(1991), and Holmgren (1998). Species nomenclature and native/non-native status follow Cooperrider et al. (2001). Family classification of seed plants follows Judd et al. (2002) and Beardsley and Olmstead (2002); family classification in Lycophyta, Sphenophyta, and Pterophyta follows FNA (1993).

As of July 2002, there were three state-listed potentially threatened species known to exist in the park (ODNR, Natural Heritage Database). The areas where these species (Corallorhiza wisteriana, Corydalis sempervirens, and

Malaxis unifolia) have previously been found before were thoroughly examined to determine if they were still present there. Any other threatened or endangered species found during the study were pinpointed as accurately as possible using a

GPS unit and quadrangle maps of the area. Locality information will be given to park management and the ODNR Natural Heritage database.

Table 1. The collecting schedule for the 2003 floristic survey of SRSP. Community Types and Habitats old field (F) o = old lawns and regularly mowed areas (L) y = young marshes and lake edge (M) n = north-facing mixed oak woods (OW) s = south-facing prairie-like openings (PO) b = bottomland 26

Table 1 (cont.)

Community Types and Habitats pine plantations (PP) r = ridgetop rocky outcrops (R) mesic ravines and stream terraces (SR) young woods and disturbed areas (YD)

Week 3rd wk in March: (SRby, SRbo, 2F, 2PO, 2M) 2nd wk in July: (OWs, OWro, OWry) 4th wk in March: (OWs, 2R, 2YD, 2PP) 3rd wk in July: (2PP, 2F, 2M, 2YD) 1st wk in April: (SRby, SRbo, SRn, OWry, OWro, 4th wk in July: (SRby, SRbo, SRn, 2PO, 2M) 2R) 1st wk in Aug: (OWry, OWro, OWs, 2F, 2nd wk in April: (2L, 2YD, 2F, 2PP, 2PO) 2M, 2YD) 3rd wk in April: (SRby, SRbo, SRn, OWry, OWro, OWs) 2nd wk in Aug: (2PP, 2PO, 2L) 3rd wk in Aug: (SRby, SRbo, SRn, 2F, 4th wk in April: (2L, 2YD, 2R, 2F, 2M) 2M, 2YD) 1st wk in May: (SRby, SRbo, SRn, PP) 4th wk in Aug: (OWry, OWro, OWs, 2R) 2nd wk in May: (OWs, OWro, OWry) 1st wk in Sept: (2F, 2PO, 2M, 2L, 2YD) 3rd wk in May: (SRby, SRbo, SRn, 2YD, 2PP, 2F, 2L) 2nd wk in Sept: (SRby, SRbo, SRn, PP) 4th wk in May: (OWry, OWro, OWs, 2M) 3rd wk in Sept: (OWs, OWro, OWry) 4th wk in Sept: (2F, 2PO, 2M, 2R, 2L, 1st wk in June: (2PP, 2PO, 2R, 2YD) 2YD) 2nd wk in June: (SRby, SRbo, SRn, 2F, 2M, 2L) 1st wk in Oct: (SRby, SRbo, SRn, 2PP) 2nd wk in Oct: (OWry, OWro, OWs, 2F, 3rd wk in June: (OWry, OWro, OWs, 2PO, 2YD) 2YD) 4th wk in June: (2PP, 2F, 2M, 2R, 2L) 3rd wk in Oct: woody plants (3SR, 2YD) 1st wk in July: (SRby, SRbo, SRn, PP) 4th wk in Oct: woody plants (3OW, 2PP) *See text for explanation of study areas.

Table 2. The scale of abundance as used by Payne (1957). Abundance Description Rare Seen in only one or two places

Infrequent Seen in a few places in small, isolated groups

Frequent Seen in several places in enough abundance that it was often observed on various trips

Common Seen in a variety of habitats, almost always seen on collecting trips

Results and Discussion

Overall Summary

The 2003-2004 survey of the terrestrial vascular flora of SRSP

documented 624 species in 362 genera and 106 families. The families with the

most species were Asteraceae (88), Poaceae (43), Fabaceae (35), Rosaceae

(28), Cyperaceae (27), Lamiaceae (24), Ranunculaceae (16), Brassicaceae (16),

and Apiaceae (14). The genera with the most species were Carex (21), Aster

(13), Solidago (10), Lespedeza (7), Polygonum (7), and Quercus (7).

Approximately 19.2% of the species documented in the current study were

not native to Ohio. Of these non-native species, 16.7% were naturalized and

2.4% were casual aliens (see Chapter III for definitions). These percentages

include three species that may be native to Ohio but not to SRSP: Populus x jackii, Philadelphus sp., and Larix sp. These percentages do not include three additional species that are native to parts of southern Ohio but probably not to

SRSP: Ilex opaca, Pinus strobus, and Liquidambar styraciflua; these three species were counted as native in calculations. The families with the most non- native species were Poaceae (15), Fabaceae (15), Asteraceae (13),

Polygonaceae (7), and Brassicaceae (7).

Table 3. Comparison of the number of species, the number of families, and the percent of alien species, both naturalized and casual, between the current floristic survey and Payne’s 1957 floristic survey of SRSP. Species Families Total Naturalized Casual Alien Current Flora 624 106 19.2 16.7 2.4 Payne's 1957 Flora 534 96 23.6 18.4 4.3

Community Types

Old Field:

In 1957, Payne described “bottom land fields and meadows” as flat alluvial fields around streams. Fertile and moist, they were once heavily farmed, and

Payne notes, “the greater part of this land will be flooded when Dow Lake is completed” (p 12). This community is now restricted to small areas on the east side of Dow Lake along the Lake Trail (Figure 3), which are higher in elevation than the “alluvial fields” of Payne’s time.

One hundred seventy-two species were identified in old fields. Of these, only 11 were restricted to this habitat (Table 4), and all of them were either infrequent or rare in the park. Hence, the most abundant species in old fields are also found in other habitats. Thirty-three percent of the 171 species found here were naturalized aliens (Table 4). Next to lawns, this community has the highest percentage of alien species.

Figure 3. Map of SRSP, showing the location of the marshes around Dow Lake and the old field communities. 30

Table 4. The number of species found in each common community type in SRSP, including the number restricted to each community, the number characteristic of each community (of the species restricted to a community type, those that are common or frequent in abundance), and the number and percent of naturalized and casual alien species in each community (excludes Ilex opaca, Pinus strobus, and Liquidambar styraciflua). # of Aliens % Alien Community # of Species # Restricted # Charac. Nat. Cas. Nat. Cas. F 172 11 0 56 0 33 0 L 32 1 0 21 0 67 0 M 64 42 24 7 0 11 0 OW 159 41 16 14 1 9 0.6 PP 106 0 0 20 4 19 4 SR 300 94 31 33 8 11 3 YD 351 40 10 99 9 28 3

Lawns and Regularly Mowed Areas:

There are lawns in the swimming area, by the boat rental building, in the campground, around the firing range, and around park headquarters. Thirty-two species were found in lawns, but only one, Lotus corniculatus, was not found in

any other habitat (Table 4). The lawn habitat had the greatest percentage of alien

species (67%) of any community in SRSP, over three times the alien percentage

of the park as a whole (Table 3 and 4).

Marshes and Lake Edge:

For the purpose of this study, the term marsh is defined broadly to include the edges of Dow Lake that support emergent species and where the water level is continuously above the soil surface, as well as the areas adjacent to the lake edges where the water level is close to the surface of the soil but not 31

continuously above it. Typically trees and shrubs are absent in these areas, with

the exception of the occasional Salix sp. and one individual of Betula nigra.

Marshes in SRSP occur mostly around the edges of Dow Lake (Figure 3).

There is also a small marshy area around the beaver pond in the northernmost

section of the park (Figure 4). These areas are very species-rich (Table 5) and

similar in composition. Emergent species growing in the water include: Typha

latifolia and T. angustifolia, Sagittaria latifolia, Alisma subcordatum, Juncus spp.,

Salix nigra, and Hibiscus moscheutos. Of these, Typha spp. and H. moscheutos are most abundant.

Marshy areas where the water level is below the soil surface in the summer frequently support dense stands of Carex and Scirpus spp., Onoclea sensibilis, Agrimonia gryposepala and Mentha x piperita. Grasses are also present, but of much less importance than the sedges; species include Leersia virginica, Eragrostis gigantea, and Phalaris arundinacea. Species of note include

Cardamine rotundifolia (found only at the head of Ramp Valley (Figure 3)), Betula

nigra (found in one marsh along the north side of the lake) and Cephalanthus

occidentalis (found with C. rotundifolia and in a marsh at the northern-most tip of

Dow Lake). Many other herbaceous species occur in these areas, although not

in large numbers (Table 5).

Table 5. Characteristic species found in the marshes of SRSP, Athens County, Ohio and their wetland status (Reed 1996). OBL = obligate wetland (occurs naturally in wetlands 99% of the time); FACW = facultative wetland (67-99%); FAC = facultative (34-66%); FACU = facultative upland (1-33%). Species Wetland Status Species Wetland Status Bidens tripartita OBL Hibiscus moscheutos* OBL Boehmeria cylindrica FACW Hypericum mutilum* FACW Carex amphibola* FAC Juncus tenuis FAC C. frankii OBL Lysimachia nummularia FACW C. lupulina OBL Mentha x piperita* FACW C. normalis FACU Penthorum sedoides OBL C. shortiana FAC Polygonum sagittatum OBL C. vulpinoidea OBL Salix interior OBL Cyperus echinatus* FACU S. nigra FACW C. flavescens* OBL Scirpus atrovirens OBL C. strigosus FACW S. polyphyllus* OBL Epilobium coloratum FACW Typha latifolia OBL

* Species not found by Payne.

Mixed Oak Woods:

Mixed oak communities have a canopy composed mainly of oak species, although most have other species that co-dominate such as hickories or maples.

These communities are most often found on ridge tops and upper slopes, but mesic

oak woods occur from mid- to lower-slope positions.

One hundred fifty-nine species were identified here, 41 of which are

restricted to mixed oak communities. Of the species restricted to this community,

16 were common or frequent in abundance (Table 4) and could therefore be

considered characteristic of mixed oak woods. These are Antennaria

plantaginifolia, Carya tomentosa, Conopholis americana, Cunila origanoides,

Hieracium venosum, Heuchera americana, Oxydendrum arboreum, Porteranthus 34

stipulatus, Quercus prinus, Saxifraga virginiensis, Silene virginica, Smilax glauca,

Thalictrum dioicum, Thalictrum thalictroides, Vaccinium pallidum, and Viburnum acerifolium.

Nine percent of the species found in mixed oak communities were

naturalized aliens, and one (0.06%) species (Pyrus communis) was a casual

alien.

Pine Plantations:

This community type was created artificially when the Division of Parks

planted pines in open areas within the land that was to become SRSP, and it did

not exist when Payne conducted the original survey in 1957. These plantations

are scattered throughout the park.

One hundred six species were identified in pine plantations, but since red

and white pine are planted in other areas of the park as well (e.g., near the boat

rental office, by various parking areas, etc.), no species were restricted to this

community type.

Of the 106 species found in pine plantations, 19% were naturalized alien

species, and 4% were casual alien species (Table 4).

Mesic Ravines and Stream Terraces (Mixed Mesophytic Forest):

The term “mixed mesophytic” is a broad category (see Braun 1950) which,

for this study, includes forests whose canopy is not dominated by oaks or pines.

Mixed mesophytic forests in SRSP are typically found on stream terraces, the

bottoms of ravines, low-lying areas, and mid to lower slopes. 35

Three hundred species were found in such areas, 94 of which are

restricted to this community type. Of those species restricted to mixed

mesophytic communities, 31 are “characteristic” based on abundance ratings

(Table 4). Some of these include Adiantum pedatum, Allium tricoccum,

Arisamea triphyllum, Asarum canadense, Caulophyllum thalictroides, Cystopteris protrusa, Geranium maculatum, Laportea canadensis, Phegopteris

hexagonoptera, Platanus occidentalis, Polemonium reptans, Trillium

grandiflorum, and Viola striata. Of the 300 species, 11% were naturalized aliens,

and 3% were casual aliens (Table 4).

Young Woods and Regularly Disturbed Areas:

For the purpose of this study, young woods are those whose canopies closed since ca. 1970 (as determined from air photos). These stands can be found throughout the park on ridges, in low-lying areas, and along abandoned roadways. Also included in this community type are waste and “dump” areas where park maintenance staff deposits felled trees, unused mulch and other debris. There are two of these along State Park Road, one on the east side and one on the west side, just past the camping area, while behind park headquarters is a waste area where unused boards, pipes and such are stored. These areas may be mowed periodically, and some may have experienced some other type of recent earth disturbance. Trail edges and roadsides are also included in this community category. 36

Of all the community types, this was the most species rich. Three

hundred fifty-one species were identified in this community, 40 of which were

found nowhere else. Of these 40, 10 can be considered “characteristic” based

on abundances (Table 4): Acer saccharinum, Ambrosia artemisiifolia, Ambrosia

trifida, Arctium lappa, Centauria dubia, Erechtites hieracifolia, Physalis longifolia,

Polygonum arenastrum, Polygonum convolvulus, and Sonchus asper. Twenty- eight percent of the 350 species were naturalized aliens, while 3% were casual alien species (Table 4).

Unusual Habitats

In addition to the seven widespread community types, there are two less frequent habitats in SRSP: prairie-like openings and rocky outcrops.

Prairie-Like Openings:

Relict communities of prairie plants in Ohio are confined mostly to areas that were known to have been prairie at the time of settlement over a century ago

(Transeau 1935). Most of these are limited to the north and west parts of the state and do not invade and become established through secondary succession on adjacent disturbed land (Transeau 1935). Rarely, prairie habitat can also be found in southeastern Ohio. Buffalo Beats, a remnant prairie described by

Wistendahl in 1975, and again by Hardin in 1988, is located in northern Athens

County.

For the purpose of this study, an area was considered “prairie-like” if it had dry soil conditions, no large trees, and at least two species indicative of prairies. 37

Three such prairie-like openings occur in SRSP (Figure 5). In these areas (and

nowhere else) there are a total of five taxa generally considered characteristic of prairies (Weaver and Fitzpatrick 1934, Cusick and Silberhorn 1977, Gleason and

Cronquist 1991): Lithospermum canescens, Andropogon gerardii, Physostegia virginiana ssp. praemorsa, Carex tetanica, and Ratibida pinnata.

Opening #1 (Figure 5) is the least characteristic of the category. Located

on the edge of a pine plantation, it is being invaded by Pinus strobus. There is

some grass (mostly Panicum and Elymus spp.), and the one prairie species that

occurs here, Lithospermum canescens, is scattered among the pines and

grasses.

Opening #2, located on the top of a ridge (Figure 5), conspicuously

emerges out of the surrounding oak woods because of the presence of a large

stand of Andropogon gerardii. Two other prairie taxa occur here: Lithospermum

canescens and P. virginiana ssp. praemorsa. The only woody species in the small area are Cercis canadensis and Diospyros virginiana.

Opening #3 is the largest, extending from the bridle path parking area

south to a nearby ridge top (Figure 5). Two of the three prairie species found

here, Carex tetanica and Ratibida pinnata, were found nowhere else in the park,

and small clumps of Andropogon gerardii were also observed.

In prairie opening #3, large patches of Lithospermum canescens extend

along a nearby, little-used roadside and provide a spectacular display of flowers

in early May. In addition to the prairie species found in all three openings, I also 38

Figure 5. Map of the eastern portion of SRSP, showing the location of the three prairie-like openings discovered during the study.

found Blephilia ciliata and Helianthus hirsutus. Helianthus hirsutus is also

prominent in the Buffalo Beats Prairie (Wistendahl 1975, Hardin 1988), and B.

ciliata was found nowhere else in the park.

The prairie-like openings in Strouds Run may represent depauperate

relics from the eastern edge of the prairie peninsula. Based on historical air

photos, these areas were used for agricultural purposes until at least 1939. The

fact that these few representative prairie species have managed to survive until

this day is remarkable.

Occasional management will be necessary to ensure the continued

existence of these unusual communities. When Hardin (1988) revisited Buffalo

Beats Prairie 13 years after an initial survey (Wistendahl 1975), he discovered

that the prairie was succumbing to woody plant succession, and the abundances

of the prairie species had declined. A management program consisting of annual

burns and woody species removal resulted in an increase in prairie species

abundance. In Strouds Run, prairie opening #1 has only one prairie species left

and has been invaded by Pinus strobus. The prairie-like openings in SRSP

would certainly benefit if a management plan involving burning, cutting, or both

were implemented.

Rocky Outcrops:

Many of the deep ravines in SRSP have rocky outcroppings or rock shelters within them. Additionally, many steep slopes have rocky outcrops near their top. The majority of these rocks are sandstone (Payne 1957). While these 40

outcrops are not heavily vegetated, six species, five of which are ferns, grow nowhere else in the park. The most common of these, Polypodium virginianum occurs on many rocks in the park. Rocks that are continually moist from seepage have a thick covering of moss and liverworts and often Asplenium rhizophyllum as well. Four additional species that are rare in SRSP were found on only one or two rock outcrops. These are Aquilegia canadensis, Pellaea atropurpurea, Asplenium pinnatifidum, and A. trichomanes. An additional infrequent species, Huperzia lucidula, was found growing on rock in two of the four locations where it was observed; the largest population of this species is shown in Figure 4.

Potentially Threatened Species

In July 2002, the ODNR Natural Heritage Database included the locations of three state-listed potentially threatened species in SRSP: Corallorhiza wisteriana, Corydalis sempervirens, and Malaxis unifolia. Of these, only C. wisteriana was found during the current study. However, three additional state- listed potentially threatened taxa were discovered: Arabis hirsuta var. adpressipilis, Cystopteris tennesseensis, and Spiranthes ovalis (Figure 6 and 7).

The areas where Corydalis sempervirens and M. unifolia were previously found were searched thoroughly at least once a week throughout the spring and summer of 2003 and 2004. Corydalis sempervirens is a showy plant; because I searched for it in two consecutive seasons, it is reasonable to conclude that it no 41

Figure 6. Map of the southwest portion of SRSP, showing the approximate locations of two of the potentially threatened taxa found during this study. 42

Figure 7. Map of SRSP showing the approximate location of three of the potentially threatened species found during the study. The location of Corallorhiza wisteriana was mapped with a GPS unit. 43

longer exists in the park. Malaxis unifolia is inconspicuous and could have been

overlooked.

Of the six potentially threatened species currently or previously found in

SRSP, Payne documented Malaxis unifolia and Cystopteris tennesseensis. He

indicated that the status of M. unifolia was rare and that it was only found along what is now State Park Road, near a foundation remnant across from the campgrounds. Cystopteris tennesseensis was formerly included within C. fragilis

(FNA 1993), and what Payne recorded as C. fragilis was identified as C. tennesseensis by Chris Haufler (University of Kansas).

Corallorhiza wisteriana was found in a mature mixed oak forest area both by a previous observer (ODNR Natural Heritage Database) and in the current study, making its presence there in 1957 highly probable. Given its inconspicuous appearance, however, it could have been easily overlooked by Payne. The site where Corydalis sempervirens was noted by the ODNR is also a mixed oak forest that existed in 1950. This species was not found in either the present study or

Payne’s. I found Arabis hirsuta var. adpressipilis only in an area of the park that was acquired after Payne conducted his survey. I observed Spiranthes ovalis three times in young woods (Figure 6), once in mesic forest (not mapped), and once in a pine plantation (Figure 7). Cusick and Silberhorn (1977) stated that S. ovalis is found in wet fields and openings. Since the area where I found it was not forested in 1957, S. ovalis may have existed in the park at that time. It is a small plant that is easily overlooked. 44

Comparison of the 1957 Flora with the Current Flora of Strouds Run State

Park

The total number of species discovered during the present survey of

SRSP was 623, while Payne found only 534 species in the Athens State Forest

of 1957. Twenty-five percent of the 534 species documented by Payne were not

rediscovered during the present survey. The 1957 flora had a higher percentage

of both naturalized and casual alien species (Table 3) than the current flora.

Factors that may have contributed to the differences between the two floras

include: changes in habitat, addition of artificial communities (e.g., Dow Lake and

pine plantations), expansion of the park, and differing methodologies in the two

studies.

Open areas associated with abandoned houses and roads that were

present during Payne’s time are examples of habitats lost due to succession since 1957. During his survey, Payne located 12 abandoned home sites and encountered 32 cultivated species still persisting at or near these sites. Some of these species not found in the current study include corn (Zea mays), tomato

(Lycopersicon esculentum), weeping willow (Salix babylonica), Japanese quince

(Chaenomeles lagenaria), spiraea (Spiraea vanhouttei, S. prunifolia), peony

(Paeonia lactiflora), and ornamental roses (Rosa alba, R. harisonii, and R.

odorata), among others.

In comparison, I found only nine abandoned home sites that still have

foundation blocks visible. A few species continue to persist around them, 45

including daffodil (Narcissus pseudonarcissus) and myrtle (Vinca minor). Mock orange (Philadelphus sp.) and wisteria (Wisteria sp.) still persist around an abandoned house in Blue Ash Valley (Figure 8), which, unlike the other home sites, is still standing. This home site lies outside of the area studied by Payne, since the park acquired it after 1957.

Most of the species described by Payne as associated with remnants of home sites are naturalized in Ohio. Some examples include Chenopodium album,

Amaranthus retroflexus, Polygonum pennsylvanicum, P. persicaria, Echinochloa crusgalli, and Setaria viridis. However, these were not encountered during the present study, presumably because of the elimination of appropriate habitat due to succession.

Some of the roads that ran through the park in 1957 have been rerouted or abandoned. For instance, much of the original Strouds Run Road is now under

Dow Lake, and what used to be Whitsel Hollow Road is now a trail. Additionally,

Payne noted remnants of a road in the southeast portion of the park, which is barely visible today as a graded track through the forest. Any species that took advantage of the disturbed areas along these roads were lost as forest began to take over. Although there are roads within the park today, the species found in the disturbed areas along them were not always the same as those found by Payne.

Some species that are currently common in such disturbed areas are exotics that have spread into the area or greatly increased in abundance since 1957 (e.g.

Lonicera maackii, L. japonica; see Chapter III). 46

Figure 8. Map of the southwest corner of SRSP showing Blue Ash Valley.

Two native species that have declined in abundance since 1957 are

Ceanothus americanus and Juglans cinerea. Payne described Ceanothus

americanus as occurring frequently on dry, mixed-oak ridges where sufficient

light penetrated the canopy. I found this species only once, on a south-facing,

mixed oak ridge above the swimming beach parking area. As the surrounding

forest matured, there would have been a decrease in the amount of light

penetrating the canopy, which may have led to the decline of C. americanus in the park.

Payne described Juglans cinerea as occurring frequently in moist forest

ravines and along roadsides, but I was unable to locate this species. The

explanation may lie in a canker fungus (Sirococcus ciavigignenti-juglanacaerum)

that is attacking J. cinerea throughout its range, causing severe population

decline (Schneider 1993).

The increase in the number of species found in the park today, as

compared to 1957, may be partially due to the introduction of new plant

communities through human activities. For example, Dow Lake was completed

in 1960, three years after Payne’s survey. Consequently, many of the marsh

species present today would not have occurred in the park in 1957. In fact,

Payne did not record 43% of the marsh species found during the current study.

Mature pine plantations are another example of a new community. These

were planted shortly before Payne’s survey, and the oldest would have been

about 10 years old in 1957. While there are no species that are unique to this 48

community, several that are most often found here were not documented by

Payne: Mitchella repens, Liparis liliifolia, Osmorhiza claytonii, and Goodyera pubescens. Most notably absent from Payne’s flora are Dryopteris species. In contrast, I found four species of Dryopteris within the park. They are particularly abundant in pine plantations but are also frequently encountered in mesic ravines and on north-facing slopes.

A minor contributor to the higher number of species found in the present study is the addition of 133 ha to the park since 1957. One of the additions included most of Blue Ash Valley (Figure 8), near the southwest corner of the park, which supports a species-rich mixed mesophytic forest. Species that are apparently restricted to this valley (none of which were recorded by Payne) include Fraxinus quadrangulata, Trillium flexipes, and Gymnocladus dioica.

Another addition to the park since 1957 is the northernmost section, which includes pine plantations and a marsh around a beaver pond. However, of the

242 species I found but Payne didn’t, only seven (2.9%) were restricted to the additions to the park that were made since Payne’s time.

Finally, the documentation of a greater number of species in my study may be due in part to a more intense sampling schedule. Although Payne did not report the number of hours spent in the field, he made approximately 67 collection trips during the growing season of 1956, plus a few more the following spring. His method of surveying the area was similar to, but not as thorough as, the method employed in this study. He chose “several representative areas” that 49

he visited each week. Other areas were surveyed less frequently in order to locate infrequent species. He does not explain how the representative areas were chosen or what habitats they represented. In contrast, I made approximately 123 collecting trips (about 492 hours) during the growing season of 2003 and 2004, plus numerous trips during the winter months. Areas that were representative of the seven community types and two unusual habitats were intensively studied, and the rest of the park was searched for infrequent or rare species. 50

Chapter III

Invasive Species in Strouds Run State Park

Introduction

There is no standardized terminology associated with invasive plants and their ecology, hence a number of different terms have been used in the invasion ecology literature and in floras to indicate the foreign status of introduced species

(Luken and Thieret 1997, Myers and Bazely 2003, Pysek et al. 2004). Some authors consider a plant an invader if it has the potential to spread in a new environment and cause an ecological impact (Myers and Bazely 2003, Ohio

Department of Natural Areas and Preserves (ODNAP) 2000). Others such as

Pysek et al. (2004) reserve the term ‘invasive’ for situations where human activities have changed the distribution and abundance of plants. Cronk and

Fuller (2001) defined an invasive plant as “an alien plant spreading naturally

(without the direct assistance of people) in natural or semi-natural habitats, to produce a significant change in terms of composition, structure or ecosystem processes.” But even this definition may require an explanation of what constitutes an alien species. Consequently, Pysek et al. (2004) suggested a standardized terminology for alien plants. They provided the following definitions:

Native plants -- “taxa that have originated in a given area without human

involvement or that have arrived there without intentional or unintentional

intervention of humans from an area in which they are native” 51

Alien plants -- “plant taxa in a given area whose presence there is due to

intentional or unintentional human involvement, or which have arrived

there without the help of people from an area in which they are alien”

Casual alien plants -- “alien plants that may flourish and even reproduce

occasionally outside cultivation in an area, but that eventually die out

because they do not form self-replacing populations, and rely on

repeated introductions for their persistence”

Naturalized plants -- “alien plants that sustain self-replacing populations for

at least 10 years without direct intervention by people (or in spite of

human intervention) by recruitment from seed or ramets (tellers, tubers,

bulbs, fragments, etc.) capable of independent growth”

Invasive plants -- “a subset of naturalized plants that produce reproductive

offspring, often in very large numbers, at considerable distances from the

parent plants, and thus have the potential to spread over a large area”

Transformers -- “a subset of invasive plants (not necessarily alien) that

change the character, condition, form or nature of ecosystems over a

substantial area.” [There is an apparent inconsistency in these

definitions, as a “transformer” must also be alien by virtue of the

definitions of “invasive” and “naturalized”].

Invasive species have been studied in various community types because of their potential to displace native flora and modify community structure and function (Deering and Vankat 1999, Huenneke and Vitousek 1990). Studies 52

documenting floristic change have shown a rise in alien plant species and a

decline in the number of native species (Frankel 1999, Robinson et al. 1994,

Henry and Scott 1981). Frankel (1999) reported that almost 30% of the species in a reserve in New York were invasive aliens. As non-native species multiply, an increasing number of native species are threatened. Therefore, it is crucial to document recent floristic changes in natural communities, in order to evaluate the potential for preserving the native flora of remaining natural landscapes

(Westman 1990, Robinson et al. 1994).

In Ohio, more than 60 plant species are recognized as invasive (ODNAP

2000), with about 12 that could be considered “transformers” (Pysek et al. 2004).

These include Lonicera japonica, Polygonatum cuspidatum, Elaeagnus umbellata, Rhamnus spp., Lythrum salicaria, Phragmites australis, Phalaris arundinacea, Alliaria petiolata, Rosa multiflora, Lonicera maackii, Celastrus orbiculatus, and Ailanthus altissima (ODNAP 2000). Some of these species are not yet a threat to native ecosystems in southeastern Ohio; for example,

Rhamnus spp. are much more frequent in the northern and central part of Ohio,

while Lythrum salicaria is well established only in the northern part of the state

(ODNAP 2000).

All standard floras should include a list of alien and naturalized plants in order to facilitate comparisons of the introduced taxa of different geographical regions (Pysek et al. 2004) and evaluate change over time. In this sense, floristic work and voucher specimens are very important to the understanding of the 53

biology of invasive species, and their importance should not be underestimated because they can help manage potential threats to native communities through early detection and elimination of the invasives (Hobbs and Humphries 1995,

Weber 2003, Prather et al. 2004). It follows that even the best described areas of the U.S., especially those most disturbed by humans, should be continually monitored so new introductions can be found and described, and known introductions that may become invasive can be watched.

Previous floras of unglaciated southeast Ohio have made the distinction between native and non-native species. For example, 23% of the vascular species in unglaciated southeast Ohio are non-native (Cusick and Silberhorn

1977). However, more recent floras in Myanmar (Kress et al. 2003) and Florida

(Looney et al. 1993) have, unfortunately, neglected to make any distinction between native and naturalized alien species (Prather et al. 2004). In order to avoid this flaw, each species described in this survey is noted as a native or naturalized alien species. Because the flora of SRSP has been previously surveyed (Payne 1957), there is an opportunity to examine the changes in abundance of invasive species over the last 50 years.

Methods

The ODNR’s list of plants invasive in Ohio (ODNAP 2000) was used to determine which species are known to be invasive in southeastern Ohio.

Payne’s flora was consulted to establish if he documented the presence of invasive species found in the present study or other invasive species that I did 54

not find. The abundance of each invasive species was then compared between

the two studies to determine if there had been any changes.

Results and Discussion

Nine species that would be considered transformers by Pysek et al. (2004)

were found during my floristic survey of SRSP (Table 6). Six of these species

were absent in 1957, and the others have increased in abundance since then.

Interestingly, there were no invasive species found in 1957 that were not found

during the current study, and although the proportion of the flora that is exotic has decreased (Table 3), the number and abundance of invasive species has

increased dramatically.

Table 6. The abundance of invasive species in 1957 and their current abundance within SRSP, Athens, Ohio. Abundance Species Present 1957 Ailanthus altissima Frequent Infrequent Alliaria petiolata Frequent Absent Celastrus orbiculatus Frequent Absent Elaeagnus umbellata Frequent Absent Lonicera japonica Common Frequent L. maackii Frequent Absent Microstegium vimineum Infrequent Absent Polygonum cuspidatum Infrequent Rare Rosa multiflora Common Absent

The largest threat to native species diversity within the park comes from

Japanese honeysuckle (Lonicera japonica), Asian bittersweet (Celastrus 55

orbiculatus), multiflora rose (Rosa multiflora), Amur Honeysuckle (L. maackii), garlic mustard (Alliaria petiolata), and Asian stilt grass (Microstegium vimineum).

Japanese Honeysuckle:

Japanese honeysuckle (Lonicera japonica) is native to eastern Asia and was introduced to the U.S. in 1862 on Long Island (Virginia Native Plant Society

(VNPS) 1995). It was originally planted (and sometimes still is) as an ornamental ground cover and came to be used for erosion control and wildlife food and habitat (Nuzzo 1997).

Many facets of Lonicera japonica’s life history cause it to be a threat to natural communities. It is a prolific fruit producer, and birds spread it into new areas at considerable distances from the original source (Nuzzo 1997). Its higher photosynthetic rate enables it to easily outcompete native species for light

(Sasek and Strain 1991, VNPS 1995). Once established, L. japonica grows by vigorous runners, eventually engulfing small trees and shrubs, which may collapse under its weight (Robertson et al. 1994, VNPS 1995, Nuzzo 1997).

Additionally, few plants can survive under the shade it creates (Nuzzo 1997).

Not only can this plant smother, collapse, and outcompete native vegetation for light, but the competition for underground resources also adversely affects tree growth by reducing leaf size and expansion rate (Dillenburg et al.

1993). Eventually, the forest structure is simplified; the understory becomes more open and species diversity decreases (VNPS 1995, Nuzzo 1997). 56

One of the most common plants in SRSP, Japanese honeysuckle can be

found in mesic and oak woods and pine plantations; however the species prefers

well lit, disturbed areas (Dillenburg et al. 1993, Nuzzo 1997). It is commonly

present in the park as a dense blanket covering native vegetation along trails,

roads and woodland edges and as a dense mat on the floor of young forests.

Although not as common as in younger, more open woods, L. japonica can also be found in older forests. Although its growth is not as rampant under a closed canopy, it can persist for years until a canopy opening enables it to increase its growth (Dillenburg et al. 1993, Robertson et al. 1994).

The abundance of Japanese honeysuckle in SRSP is a possible threat to native species of old fields and the forest understory. To preserve the overall species diversity of SRSP, control of Lonicera japonica should be undertaken.

The most effective control method appears to be a combination of burning and herbicide application (VNPS 1995, Nuzzo 1997). Japanese honeysuckle is very

difficult to contain once it is established, so the VNPS (1995) recommends regularly

surveying a site for its presence and destroying every plant that is found. However,

cutting, pulling, or burning only weakens the plant temporarily. For permanent

eradication, mechanical removal must be repeated for every new flush of growth.

This may be feasible under shaded conditions where the plant regenerates more

slowly (P.D. Cantino, pers. comm.), but mechanical removal may not be practical in

sunny sites. Herbicides, however, pose a threat to native species. Their

application is not recommended when mechanical removal is an option. 57

Asian Bittersweet:

Another native to Eastern Asia, Asian bittersweet (Celastrus orbiculatus), was first introduced to the U.S. in the 1860s as an ornamental plant (Dreyer

1994). It can still be found in many nurseries (often misidentified as the native C. scandens), where it is cultivated for its attractive fruits, which are used in dried flower arrangements (Bergmann and Swearingen undated, Dreyer 1994, VNPS

1995). It is possible that this plant continues to be used for highway landscaping, wildlife food and cover, and erosion control (Dreyer 1994).

Like Japanese honeysuckle, Asian bittersweet possesses many traits that give it a competitive advantage over native species. For instance, it has a much higher seed germination rate than the native species, Celastrus scandens

(Dreyer et al. 1987, Dreyer 1994). A study conducted in Connecticut by Clement et al. (1991) found that C. orbiculatus had a 70% germination rate, compared to

20% for C. scandens. Another advantage is its ability to adapt to different light levels. For example, Dreyer (1994) reported that the photosynthetic rate of C. orbiculatus will keep increasing with increasing light intensity, while the photosynthetic rate for C. scandens only increases somewhat before reaching a plateau, after which increased light levels have no effect on photosynthetic rate.

C. orbiculatus can also rootsucker prolifically, especially after being cut or damaged, which results in large clonal patches from one or a few established seedlings (Dreyer 1994). The rapidly growing vines can quickly cover native vegetation, killing it by smothering and constricting solute flow (Bergmann and 58

Swearingen undated, Siccama et al. 1976, Dreyer 1994). Additionally, trees with extra weight in their canopies and girdled stems are more susceptible to wind damage (Siccama et al. 1976).

As if these attributes weren’t enough of a threat, Celastrus orbiculatus can hybridize with the native species C. scandens (Dreyer et al. 1987, Dreyer 1994), which could mean the loss of the genetic identity of C. scandens. This, combined with the fact that C. scandens appears to be less common than in the recent past, could result in its extinction (Dreyer et al. 1987). In Connecticut, C. scandens has been identified as a Species of Special Concern (i.e., more information on its distribution and abundance is needed), and it is considered a non-reproducing rare plant in the Great Smoky Mountains National Park (Dreyer 1994). In SRSP, C. scandens occurs very infrequently, usually in the same kind of habitat as C. orbiculatus.

Easily found within the park, Asian bittersweet prefers open, disturbed areas such as trail edges and parking or picnic areas. Some of the largest populations occur in young woods, especially the pine plantations. It is also present within the understory of older forests, although in much smaller numbers.

The communities in SRSP that are most threatened include old fields and woodland edge, where bittersweet is outcompeting many of the same species threatened by Japanese honeysuckle.

To avoid the possible loss of Celastrus scandens and damage to whole plant communities within SRSP, C. orbiculatus needs to be brought under 59

control. Although this plant is extremely difficult to control once established,

Dreyer (1988 as cited by Dreyer 1994) developed a successful method. In early

spring, it is mowed to the ground, and then allowed to resurge. After one month,

foliar applications of a 1-2% triclopyr herbicide resulted in a 100% root kill. The

same study found herbicides containing glyphosate ineffective. The

disadvantage of Dreyer’s method is that it is only effective on dense, low patches

where herbicide use is appropriate.

Multiflora Rose:

Multiflora rose (Rosa multiflora) is a native of eastern Asia which has been introduced to the U.S. many times since the late 1700s. Originally used for garden plants and as root stock for ornamental roses, it was also extensively planted from the 1940s to the 1960s in the eastern U.S. as a wildlife plant, for erosion control, and as a living fence (Eckhardt 1987, Amrine 2002). It has been declared a noxious weed in at least ten states, including Ohio and West Virginia, where there are 1.5 million acres of infested land (Amrine 2002).

Multiflora rose is plentiful in SRSP, occurring most often in young forests, along trail edges, and in some valley bottoms. It can also be found in open areas along streams, at the border of marshes where it forms thickets with native species, and in old field situations where it grows as isolated clumps. Rosa multiflora is frequently profuse on ridges that are in close proximity to roads. For example, there are large patches of multiflora rose beneath the canopy and along

Vista Point Trail on the ridge between the campground and Strouds Run Road. It is 60

also well established along the roadways and parking lots within the park. Like

Lonicera japonica, Rosa multiflora is sometimes found in the understory of older forest, where an opening in the canopy can cause a few stems to quickly become a thicket. Currently, R. multiflora poses the largest threat to successional forest habitat and woodland edges in the park.

Rosa multiflora is a successful competitor because it is a very prolific seed producer. Per year, one cane is able to produce as many as 17,500 seeds, which can remain viable for up to 20 years (Eckhardt 1987, Underwood et al. 1996,

Amrine 2002). The fruit is highly sought after by birds, which greatly aid in spreading this plant (Eckhardt 1987, Amrine 2002). Once established, R. multiflora spreads rapidly, growing quickly and reproducing asexually by rooting at the tips of arching canes (Underwood et al. 1996, Amrine 2002). It forms dense clumps of vegetation, and an isolated plant can produce a clump up to 33 feet in diameter. A single plant can reach heights of 6 to 15 feet, displacing native vegetation by outcompeting it for light, nutrients, and space (Eckhardt 1987, Underwood et al.

1996).

Unlike the previously discussed invasive species, Rosa multiflora is known to be susceptible to biological control methods. Several of these are suggested in the literature (i.e. European rose chalicid, rose mosaic virus) (Eckhardt 1987,

Underwood et al. 1996, Amrine 2002). Additionally, the multiflora rose plants in

SRSP exhibit symptoms of rose rosette virus (RRV). This disease has a 100% mortality rate and kills plants within one to two years of infection (Tisserat 2004). 61

Spread by an eriophyid mite (Phyllocoptes fructiphilus), symptoms include rapid shoot growth and a “witch’s broom” or clustering of small branches that are excessively thorny and produce small, deformed leaves with reddish purple pigmentation (Lehman 1999, Tisserat 2004). In the park, multiflora rose plants infected with RRV occur about half as often as healthy plants.

The most widely used methods for controlling multiflora rose are mechanical and chemical (Eckhardt 1987). Mowing several times a year is effective for preventing seedlings from becoming established, but in habitats where there are

many desirable species, plants must be removed individually (Underwood et al.

1996, Amrine 2002). Applications of herbicide have been shown to be effective, but

because of the seed bank’s longevity, repeated applications are usually necessary

to keep the plant under control (Eckhardt 1987, Underwood et al. 1996). A

combination of both of these methods--mechanical removal followed by herbicide

application--seems to be the most effective method when conducted late in the

growing season (Underwood et al. 1996, Amrine 2002).

Amur Honeysuckle:

Amur Honeysuckle (Lonicera maackii) is native to central and

northeastern China, Manchuria, Korea and (less commonly) Japan (Batcher and

Stiles undated). Originally used as an ornamental, it was first introduced to North

America at the Dominion Arboretum in Ottawa, Canada in 1896 (Gould and

Gorchov 2000) and the New York Botanical Garden in 1898 (Batcher and Stiles 62

undated). It is now naturalized in 24 eastern and central states as well as in

Ontario, Canada (Hutchinson and Vankat 1998, Gould and Gorchov 2000).

Lonicera maackii has been promoted by the U.S. Department of Agriculture for its wildlife, shelterbelt, and ornamental value (Batcher and Stiles undated, Gould and Gorchov 2000). Many nurseries still sell L. maackii and other invasive

Lonicera spp. (L. tatarica, L morrowii), and this practice will continue to introduce L. maackii to areas that are not already colonized (Batcher and Stiles undated).

Lonicera maackii has several physiological traits that have caused it to become invasive. It produces large quantities of fruit that are dispersed by birds

(Luken and Mattimiro 1991, Gould and Gorchov 2000). However, unlike Asian bittersweet and multiflora rose, these fruits are of “poor quality” and are probably not dispersed until late winter when other food sources have become scarce

(Luken and Mattimiro 1991, Hutchinson and Vankat 1998). A more important trait is its earlier leaf expansion and longer leaf retention when compared with native trees and shrubs (Batcher and Stiles undated, Hutchinson and Vankat 1997). This trait and its ability to increase primary productivity with increasing light levels (Luken

1988, Hutchinson and Vankat 1997, Luken et al. 1997) allow it to outcompete native species for light. Additionally, herbivory is uncommon due to a lack of natural predators (Batcher and Stiles undated, Gould and Gorchov 2000).

Lonicera maackii is present in many areas of SRSP. It is most often found in young woods, along trails and roadways, and in forests adjacent to roads. The largest populations occur along the Finger Rock Trail and on the 63

ridges south and east of it. A medium sized population exists on the ridge

between Strouds Run Road and the camping area. Small, non-reproducing

individual plants are common in mature forest understories.

Studies have shown that Lonicera maackii usually invades young forests

that have experienced some form of canopy disturbance (Luken and Mattirmiro

1991, Hutchinson and Vankat 1997 and 1998, Deering and Vankat 1999).

Indeed, aerial photos indicate that the areas in Strouds Run with the largest

populations of L. maackii were not forested in 1950.

Many studies have shown that Lonicera maackii negatively affects the growth and survival of native tree seedlings and herbs. In an experiment near

Oxford, Ohio (Gorchov and Trisel 2003), seedling survival of Acer saccharum,

Fraxinus americana, Quercus rubra, and Prunus serotina was increased in plots where L. maackii shoots (and therefore competition for light) were removed.

They also tested below-ground competition and found that tree seedling survival increased in plots where L. maackii roots were removed. An earlier experiment in Kentucky (Luken et al. 1997) tested the short-term response to increased light in a native shrub Lindera benzoin versus L. maackii. They found that the ability

of L. maackii to outcompete L. benzoin for light in situations where the amount of

light changed due to disturbance is “remarkable” (p. 339). Additionally, in a study

by Gould and Gorchov (2000), the reproduction of three native annual herbs

(Galium aparine, Impatiens pallida, and Pilea pumila) was enhanced in plots 64

where L. maackii was removed. They also found that the overall survival of I. pallida and P. pumila was increased where L. maackii was removed.

These studies suggest that in SRSP, Lonicera maackii is a threat to native herbs (especially spring epheremals because of its early leaf expansion), shrubs, and trees. The species examined in the study by Gorchov and Trisel (2003) are all common in Strouds Run, and the effect of L. maackii on these as well as other species that have not been tested may result in a modification of forest succession and reduced species diversity.

The potential for restoring natural habitats is much higher if management of Lonicera maackii is begun in the early stages of its establishment (Batcher and

Stiles undated). For this reason, its management in SRSP should be undertaken immediately.

Habitat-specific methods of control, including mechanical and chemical, have proven to be effective (Luken and Mattimiro 1991). In forested settings, repeated clipping alone will control adult plants, while in open settings, repeated clipping combined with herbicide treatment is usually necessary. The most successful method of chemical control appears to be a cut stump treatment of

20-25% solutions of glyphosate or triclopyr (Batcher and Stiles undated).

Garlic Mustard:

Native to Europe, garlic mustard (Alliaria petiolata) was first recorded in

North America in 1868 on Long Island, New York (Nuzzo 1993). Immigrants may

have brought it here for use as a salad herb (Myers and Anderson 2003). By 65

1990 it was well established in North America, present in 27 Midwestern and

northeastern states, Oregon, Utah, and three Canadian provinces (Nuzzo 1993,

McCarthy 1997, Roberts and Anderson 2001).

The species-rich spring understory communities of SRSP are most at risk

from garlic mustard. It is a biennial that actively grows throughout the winter

(whenever temperatures are above freezing) and achieves maximum

photosynthetic rates in the early spring when indigenous ground species of the

herb layer are still dormant and high levels of light can reach the forest floor

(Myers and Anderson 2003). Furthermore, unlike the native spring ephemerals

such as Dicentra cucullaria, D. canadense, Claytonia virginica, Cardamine

concatenata, C. douglassii, and Trillium spp., Alliaria petiolata can extend its growing season into the summer by elongating its stem and producing new leaves adapted to ambient light levels (Byers 1987). Once introduced into an area, garlic mustard will outcompete native plants by monopolizing light, moisture, soil nutrients and space (Byers 1987, Dreyer 1994, Myers and Anderson 2003).

Mature forests are usually considered relatively resistant to invasive plants

(Meekins and McCarthy 1999). However, although garlic mustard may require a disturbance to gain entrance, once present it displaces the native understory flora and reduces species diversity (Nuzzo 1993, McCarthy 1997, Roberts and

Anderson 2001). Characteristics such as the ability to produce large quantities of seed, which germinate under many conditions, rapid growth, adaptability to 66

various light levels, and self-compatibility (Nuzzo 1993, McCarthy 1997), enable

it to do so.

Several studies have suggested that Alliaria petiolata may be allelopathic, heightening its invasive ability, but results have been mixed. In an experiment by

Kelley and Anderson (1990), an extract of garlic mustard inhibited the growth and development of seedlings of tomato, lettuce, radish, and wheat. In another study,

Prati and Bossdorf (2004) tested allelopathic inhibition by A. petiolata on germination in Geum urbanum, a species found in A. petiolata’s native habitat, and

in Geum laciniatum, a species found in North American habitats invaded by A.

petiolata. They found that sensitivity to allelochemicals from A. petiolata was greater for the North American species. However, a study by McCarthy and

Hanson (1998) revealed little evidence supporting the claim that garlic mustard is

allelopathic. In their experiment, seedlings of hairy vetch, winter rye, radish and

lettuce only showed a suppression of germination and growth when levels of the

allelopathic chemicals were far greater than would be found in the natural

environment.

Another factor that could contribute to the invasiveness of garlic mustard

is its interference with mycorrhizal associations. Roberts and Anderson (2001)

showed that water leachates of garlic mustard prevented the germination of

spores of Gigaspora rosea (an arbuscular mycorrhizal fungus), inhibited the

formation of mycorrhizal associations with tomato, and significantly reduced the

germination of tomato seeds. 67

Garlic mustard is often observed growing in dense populations with few, if

any, native species co-occurring alongside it. In contrast, there is one population

I observed in the park that consisted of a few scattered plants that were over-

topped by native species that appeared to be outcompeting them. This

population is located along the creek bed on the west side of the campground.

Species such as Impatiens pallida, Laportea canadensis, Verbesina alternifolia,

Boehmeria cylindrica, Acer negundo, and Sambucus canadensis are present in

such quantities as to “choke out” the garlic mustard. An experiment by Meekins and McCarthy (1999) supports this idea. They tested the competitive ability of

Alliaria petiolata against that of three plant species (Acer negundo, Impatiens capensis, and Quercus prinus) native to the North American habitats invaded by A. petiolata. They found that A. petiolata was a poor competitor with Impatiens

capensis and Acer negundo, but was a superior competitor to Quercus prinus. In fact, I. capensis and A. negundo actually benefited from the presence of A.

petiolata, showing increased growth rates when grown together. The situation was reversed for Q. prinus, however. When grown together, the garlic mustard showed

increased growth rate while the growth rate of Q. prinus decreased. Perhaps

further study would show that some of the species in the creek bed west of the campground are also superior competitors to A. petiolata.

Garlic mustard is frequent in SRSP, although still restricted to certain areas. The largest population observed during the survey is near the bottom of the southwest-facing slope east of the dam on Dow Lake (Figure 9). 68

Figure 9. Map of SRSP showing the approximate locations of the largest populations of Asian stilt grass and garlic mustard. Size of polygon does not indicate size of population. 69

Other well established populations occur along the Finger Rock Trail and scattered along the Athens Trail. Another population is located at the head of the

Pioneer Cemetery Trail and is spreading into the forest south of the trail head.

Occasionally small clumps can be seen in older forests beneath the canopy and most often along trails.

Although Alliaria petiolata is not yet present in large quantities in SRSP, its removal should be implemented as soon as possible to preserve the diversity of the understory communities in the park. The removal of garlic mustard from the understory has been shown to result in an increase in native annuals, woody and herbaceous vines, and tree saplings (McCarthy 1997). The goal of management is to prevent seed production by removal of existing plants until the seed bank is exhausted (Nuzzo 1993). Hand removal is possible where there are small infestations amongst desirable native species (Rowe and Swearingen undated,

McCarthy 1997) but is not effective for large infestations. These can be mowed or pulled in the spring before fruiting, and the stalks should be removed from the site if fruiting has begun (Nuzzo 1993). Herbicide is also effective where few desirable species are present (Rowe and Swearingen undated, Byers 1987,

Nuzzo 1993).

Asian Stilt Grass:

Asian stilt grass (Microstegium vimineum) was first discovered in the U. S. in 1919 in Knoxville, Tennessee (Fairbrothers and Gray 1972). It may have been accidentally introduced as a result of being used for packing material for the 70

shipment of porcelain (Swearingen 1999). By 1978, M. vimineum had spread to

16 eastern states, from New Jersey to Florida and west to Ohio, Mississippi, and

Arkansas (Barden 1987, Swearingen 1999).

An aggressive annual grass, Microstegium vimineum grows rapidly and spreads by rooting at nodes along its stem (Swearingen 1999). Each plant produces 100-1000 seeds. Although its seed dispersal mechanism is not fully understood, seeds are most likely dispersed by water in stream-side habitats and during floods (Swearingen 1999, Mehrhoff 2000). Equally likely is dispersal by

“hitchhiking” on animal fur, on clothing, in cars or with nursery stock (Mehrhoff

2000).

Microstegium vimineum occurs in a variety of disturbed habitats, including river banks, flood plains, damp fields, swamps, lawns, woodland thickets, trolley tracks, roadside ditches, river bluffs, and roadsides (Fairbrothers and Gray

1972). Barden (1987) showed that M. vimineum requires a disturbance such as flooding or mowing to become established, while Benedict et al. (2001) observed its spread into undisturbed upland areas by forming satellite populations from seed transported by animals. Seeds can remain viable in the soil for approximately three to five years (Barden 1987, Tu 2000), ensuring re-growth for several years once the grass becomes established at a site, and it is capable of crowding out native vegetation only three to five years after becoming established (Barden 1987, Hunt and Zaremba 1992). 71

Although adapted to low light levels, M. vimineum is a C4 plant (Tu 2000).

It can grow and produce seed in only 5% full sunlight (Winter et al. 1982).

Furthermore, M. vimineum may alter natural soil conditions, enhancing its ability to crowd out native species. Kourtev et al. (1998) found that soil in areas invaded by M. vimineum had a thinner litter and organic soil horizon and a higher pH than soils in areas not invaded by M. vimineum. However, unlike many invasives, there is no evidence that M. vimineum produces allelopathic chemicals

(Tu 2000).

Microstegium vimineum has become established at several scattered sites in SRSP. It has been observed along the stream that drains into the large, northeast inlet of Dow Lake (Figure 9), on the banks of State Park Road near the campgrounds (Figure 10), and in an inlet north of the dam (Figure 9). The largest population is located 0.7 km northeast of the dam, where it covers the full width of an abandoned township road that forms the eastern boundary of the park (Figure 9). All of these populations occur in areas disturbed by flooding, mowing, or human and equestrian foot traffic; however, little M. vimineum has yet been observed in undisturbed forests adjacent to infested areas. 72

Microstegium vimineum probably poses the greatest threat to native vegetation in low-lying areas and stream terraces in the park because of disturbance from natural floods. It could also move into other areas with natural or anthropogenic disturbance. Imlay and Brewer (2000) claim that several parks in Maryland and Virginia “have already lost half their flora [to this grass], along with several birds that depend on native vegetation.”

Control of this aggressive grass within Strouds Run must be undertaken as soon as possible. If controlled during the early stages of infestation, the chances of successful management are high (Tu 2000). Hand pulling or mowing are the preferred methods of control for large infestations and are very effective if timed correctly (LaFleur 1996). The best time is September before the seeds mature; removal before July allows germination of new plants from the seed bank that still have enough time to mature and produce seeds before the end of the season (Tu 2000). Hand pulling in September would be effective in areas that are too wet to mow and where herbicide would kill native species. Yearly monitoring of disturbed areas and continued removal of M. vimineum in the park is a high priority.

Other Invasive Species:

The remaining three species observed during this study that are currently

listed as transformers in Ohio (Ailanthus altissima, Elaeagnus umbellata, and

Polygonum cuspidatum) do not yet pose as great a threat in SRSP as those already discussed. 74

A Philadelphia farmer first introduced tree of heaven (Ailanthus altissima) to North America in 1784 as a host for silkworms (Hoshovsky 1988, Knapp and

Canham 2000, Swearingen and Pannill 2003). It was re-introduced during the

California gold rush by Chinese miners who valued it for its medicinal and cultural importance (Hoshovsky 1988). Native to Central China, Ailanthus altissima is now well established on both coasts of the U.S. and from Canada to Argentina

(Hoshovsky 1988, Knapp and Canham 2000). It has become so prevalent in some urban areas that it has been described as a nuisance and a potential hazard along highways (Knapp and Canham 2000).

There are three areas in SRSP where Ailanthus altissima is conspicuously present. One population is located at the head of Gillette Run (Figure 11) and includes the largest specimen--a single tree that reaches well into the canopy. A second population occurs on a ridge south of the middle portion of Gillette Run

(Figure 11). The third population lies on the ridge southwest of the campground, where A. altissima is present in the understory, and saplings three to eight feet in height are frequently encountered (Figure 10).

Ailanthus altissima has many attributes of a successful invasive plant. It can reproduce asexually through the production of vigorous root and stump sprouts (Hoshovsky 1988). It can also reproduce sexually, producing large quantities of seed, which can germinate and become established in about three months (VNPS 1996, Swearingen and Pannill 2003). 75

Figure 11. Map of SRSP showing the approximate location of a population of tree of heaven. Size of polygon does not indicate size of population. 76

Although usually restricted to disturbed areas because of its intolerance of

shade, Ailanthus altissima occasionally spreads to undisturbed forested areas

(Hoshovsky 1988, Knapp and Canhan 2000). Knapp and Canham (2000) suggested that tree-of-heaven may be the most rapidly growing tree in the northeastern U.S. and that it is able to overtop native competitors and reach canopy height with just one release event.

Another factor in the success of Ailanthus altissima could be its production of phytotoxic chemicals. One of these, ailanthone, was first reported by Mergen

(1959). More recently, in a study by Heisey (1996), foliar application of ailanthone caused 100% mortality of four herbaceous species (Amaranthus retroflexus, Setaria glauca, Echinocloa crusgalli, and Zea mays) within five days of application. Lawrence et al. (1991) tested the extracts of several species native to Missouri as well as A. altissima extract on the growth of lettuce (Lactuca sp.) seedlings. They found that the only extracts that inhibited the germination and growth of Lactuca were from Ailanthus tissues. However, they failed to demonstrate that Ailanthus gains any competitive advantage from its allelopathic

properties. Research is currently being conducted on the effectiveness of these

compounds as a natural herbicide (Lawrence et al. 1991, Heisey 1996, VNPS

1996).

In SRSP, the threat from Ailanthus altissima is mainly to successional

habitats where it can outgrow native species and monopolize light, space, and

nutrients. Additionally, because A. altissima can compete and survive within

forest gaps, it could have the potential for future invasion of forest environments

(Knapp and Canham 2000). This is the case on the ridge behind the

campground and particularly in the valley of Gillette Run, where seedlings from

one mature tree are becoming established in the surrounding understory. The

individuals in both of these cases need only respond to one opening in the canopy to reach canopy height and begin producing huge quantities of seeds, enabling spread of the species to other parts of the park.

The timing is perfect for successful elimination of this species from the park, because the isolated populations are still small. One method of control is the manual removal of young seedlings (Hoshovsky 1988). Plants should be removed before they can produce seeds, and the entire root system should be removed to prevent root or stump sprouting (Hoshovsky 1988, Swearingen and

Pannill 2003). For large infestations, cutting alone may not be successful because of Ailanthus altissima’s ability to rootsprout (Swearingen and Pannill

2003); however, repeated cutting to deplete food reserves may be successful for

small infestations (Hoshovsky 1988, Swearingen and Pannill 2003). The most

effective method of control is herbicide treatment of foliage, basal bark, cut

stumps or a hack and squirt method (Hoshovsky 1988, VNPS 1996, Swearingen

and Pannill 2003).

Fungal pathogens may provide biological control of Ailanthus altissima.

Under study are the species Verticillium dahliae and Fusarium oxysporum, which

have been isolated from dead and dying Ailanthus trees in New York and Virginia

(Swearingen and Pannill 2003).

Autumn olive (Elaeagnus umbellata) is most frequently found in young woods, successional areas and disturbed areas such as trail edges. It seems to form clumps of several individuals along trails, and isolated individuals occur in old fields. E. umbellata can be found along roadways, trails, and parking areas.

Management of this species should be undertaken now before it becomes a greater problem. The best way to do this is cutting back the plants in spring and removing their roots. Any roots that cannot be removed should be treated with an herbicide to prevent root sprouts (ODNAP 2000).

The other transformer identified in this study was Japanese knotweed

(Polygonum cuspidatum). It is the least threatening to the species diversity of

Strouds Run at the present time because there are only two medium sized populations. The first one is growing adjacent to the junction of State Park Road and Strouds Run Road. The other is adjacent to the parking lot at the picnic area southeast of the Pioneer Cemetery Trail parking lot (Figure 10). Japanese knotweed spreads vigorously by rhizomes, forming large clones that exclude native vegetation, reducing wildlife habitat. It is especially threatening to riparian habitats, where rhizome pieces washed downstream can start new colonies in previously uninhabited areas (ODNAP 2000). Forest managers have the ability to completely remove this transformer from SRSP if the two existing populations are eradicated soon. The best method to remove this aggressive species is

repeated mowing during the growing season to deplete its stored reserves

(Seiger 1999).

All of the invasives discussed here have the potential to substantially

decrease the species diversity of SRSP if left unmanaged. A major part of the management process is regular monitoring of areas of concern (Pysek et al.

2004). This includes monitoring the entire park for the presence of invasive species, scouting for areas most likely to benefit from active management, and repeated visits to recently managed areas in order to continue management if necessary. Monitoring efforts should include looking for species that are invasive elsewhere; including those not on ODNR’s top ten list. Examples are privet

(Ligustrum vulgare) and Japanese barberry (Berberis thunbergii), both of which

are common in SRSP.

Management Implications

The management of invasive plant species in SRSP should concentrate

on those with the smallest populations, because they can be controlled easily,

and complete elimination may be achievable within a few years. Polygonum

cuspidatum, Ailanthus altissima, and Microstegium vimineum have the smallest

populations, but eradication of Alliaria petiolata and Elaeagnus umbellata may

also be possible at their present densities.

Invasives should be removed from sensitive areas of the park such as the

prairie openings and marshes, but also from along trails, where their seeds are

more easily transported to uninfested areas by hikers, horses, and mountain

bikes.

While many of the authors cited in this study suggest the use of herbicides

as an effective control method (Byers 1987, Eckhardt 1987, Luken and Mattimiro

1991, Nuzzo 1997, Swearingen and Pannill 2003), I do not recommend their

widespread use in SRSP. There are several reasons for this. Herbicides must be applied by persons with proper training who can distinguish desirable species from those that are not desirable. Even with proper training, nearby natives are

at risk from drifting herbicide.

Chapter IV

Changes in Abundance of Ant-Dispersed Forest Herbs

in Strouds Run State Park

Introduction

As much as one-third of herbaceous understory species in deciduous

forests of the eastern U.S. use ants as their method of seed dispersal (Beattie

and Culver 1981, Smith et al. 1989, Raven et al. 1999). These plants, known as

myrmecochores, have evolved a fleshy proteinaceous appendage on the exterior

of their seeds, called an elaiosome (Beattie and Culver 1981, Gomez and

Espadaler 1998). When the seeds mature and fall to the ground, ants transport

them to their nest where the elaiosome is eaten, and the unharmed seed is

discarded either outside the nest or in the ants’ midden (Raven et al. 1999,

Handel et al. 1981). Here the seeds may germinate and can become established. However, plants that use ants as a means of seed dispersal tend to be limited to short colonization ranges.

It has been demonstrated that one factor limiting the colonization of secondary woods by understory herbaceous species is dispersal distances

(Beattie and Culver 1981, Matlack 1994, Meier et al. 1995, Brunet and von

Oheimb 1998). These species are able to migrate very slowly, gaining only centimeters in their distributions every year (Matlack 1994). For example, Brunet and von Oheimb (1998) reported rates of migration from 0.11 m/yr to 0.77 m/yr,

while Matlack (1994) calculated migration rates ranging from 0 to 2.5 m/yr. It follows that colonization of secondary woods by herbaceous understory species must be limited by the proximity of possible seed sources. Indeed, several studies have shown that there is a general decrease in species richness and abundance with increasing distance from undisturbed forest, which could act as seed sources (Matlack 1994, Meier et al. 1995, Bruet and von Oheimb 1998).

Because of the extremely slow migration rate of many forest herb species, any value a second growth forest has in maintaining herb diversity depends on proximity to old growth stands, which act as a potential source of propagules

(Matlack 1994, Meier et al. 1995). Nonetheless, it could take decades or even centuries (Peterken and Game 1984) for herbaceous understory species to recolonize a second growth stand. It is possible, however, that the transplantation of these species into secondary forest may help restore species diversity (Meier et al. 1995).

Some ant-dispersed forest herbs native to southern Ohio (Cusick and

Silberhorn 1977) are Asarum canadense, Carex laxiculmis, Claytonia virginica,

Corydalis flavula, Dicentra cucullaria, Erythronium americanum, Hepatica acutiloba, Jeffersonia diphylla, Luzula echinata, Sanguinaria canadensis, Trillium erectum, Trillium grandiflorum, Trillium sessile, Uvularia perfoliata, Viola canadensis, V. pubescens, V. striata, and V. blanda (Beattie and Culver 1981,

Matlack 1994). While large portions of SRSP were farmed prior to 1950, other portions support relatively old and minimally disturbed forests. The current

inventory of the park’s flora can permit one to determine the number and abundance of ant dispersed species present in the park. Because Payne previously surveyed the flora of this area in 1957, comparisons of the abundances can be made to discover whether there have been any changes.

Methods

While completing the floristic survey of SRSP, the abundance of primarily ant-dispersed species was assessed using Payne’s scale. This abundance rating was then compared with that given by Payne in 1957 to determine if there have been any changes. The locations of areas where there are large assemblages of such species were noted on a map of the park (Figure 12 and

13) in case they warrant extra effort to avoid future human disturbance.

Results and Discussion

The purpose of examining abundance changes of ant-dispersed species within SRSP was to determine if 50 years with reduced human disturbance has allowed these slow-moving species enough time to increase in abundance.

Unfortunately, the scale at which abundance changes were noted is not fine enough to determine precise changes in abundances, so only overall trends were determined.

Overall, six species decreased, six species increased, and six species stayed the same. Species that shifted two steps or more on the abundance scale

(Table 2) were considered to have undergone substantial change. Of these, only one species (Uvularia grandiflora) showed a substantial reduction in abundance.

Those that showed a substantial increase in abundance are Carex laxiculmus,

Corydalis flavula, and Jeffersonia diphylla (Table 7).

Table 7. The abundance of ant-dispersed forest herbs in 1957 and theircurrent abundance within SRSP, Athens, Ohio. Abundance Species Present 1957 Asarum canadense Common Common Carex laxiculmus Infrequent Absent Claytonia virginica Common Common Corydalis flavula Infrequent Absent Dicentra canadensis Infrequent Rare Dicentra cucullaria Frequent Frequent Erythronium americanum Frequent Common Hepatica acutiloba Frequent Common Jeffersonia diphylla Frequent Rare Luzula echinata Frequent Common Sanguinaria canadensis Frequent Common Trillium erectum Rare Absent T. grandiflorum Common Common T. sessile Rare Rare Uvularia grandiflora Infrequent Common Viola canadensis Frequent Common V. pubescens Frequent Infrequent V. striata Common Common

Previous studies of ant-dispersed species (Matlack 1994, Brunet and von

Oheimb 1998) reported an average migration rate of about one meter per year.

Therefore, these species (if they are relying only on ants for seed dispersal)

should not have moved more than about 50m since 1957, and most would then

have increased only slightly or remained at the same abundance as observed by

Payne (1957). While most ant-dispersed species changed little as expected,

three species increased substantally and one species decreased substantially

(Table 7).

Fifteen of the 18 ant-dispersed species identified in this study were also

recorded in 1957. It stands to reason, then, that these species would act as a

source of propagules, allowing them to start spreading throughout the park. The

complete land-use history of SRSP is unknown, and a few small areas with very

large trees and a rich understory could possibly represent original forest (Figure

12 and 13). Regardless of their exact age, old growth forests such as these have

the potential to harbor a high number of ant-dispersed species. The decline of

some ant-dispersed species since 1957 is therefore surprising.

Factors unrelated to dispersal may be contributing to the decrease in

abundance of some ant-dispersed species. Increasing herbivory by white-tailed

deer (Odocoileus virginianus) is one possible factor. Throughout the

northeastern United States there has been a general increase in deer

populations. Authors have suggested that current deer densities are two to four

times higher than densities before European settlement (Alverson et al. 1988,

Russell et al. 2001, Rooney and Waller 2003). Several factors may be responsible for this trend, including a dramatic change in forest disturbance patterns, current forest management practices, and extirpation of natural predators (Alverson et al. 1988, Van Deelen et al. 1996, Augustine and Frelich

1998, Rooney and Waller 2003). This same trend holds true for Ohio deer

Figure 12. Map of SRSP showing the location of areas with very large trees.

Figure 13. Map of SRSP showing the location of areas with very large trees and a rich understory.

populations, with southeastern Ohio having the largest population in the state

(ODNR Wildlife Population Status Report 2003-2004).

Because herbs can never grow out of browsing range and all of their

above-ground tissue is accessible, they are particularly vulnerable to damage by

deer (Russell et al. 2001). Herbaceous plants may form a large portion of deer’s diet during spring and summer, and studies have shown that over-browsing has a negative impact on understory species populations. For example, studies using natural exclosures or similar “deer-proof” areas clearly show a reduction in the abundance of browse-sensitive herbs (Balgooyen and Waller 1995, Rooney

1997). In order to examine this further, Rooney and Waller (2003) revisited stands in Wisconsin that were surveyed in the 1940s and 50s (Curtis 1959, cited by

Rooney and Waller 2003). They were then able to compare current community structure with the historic data. They found a decline in understory herb diversity that was not due to successional stage or soil nitrogen, but to browsing intensity,

“suggesting that abundant deer directly reduce forest understory herb diversity” (p.

169).

Deer also tend to show a preference for certain herbaceous species, and this may have contributed to the pattern of abundance changes observed. In addition to a known deer favorite, Trillium spp. (Alverson et al. 1988, Augustine and Frelich 1998, Rooney and Waller 2003), many wildflowers are declining in

Wisconsin natural areas (Hemphill 2004). One of these declining species is

Uvularia grandiflora, which is also the only ant-dispersed species whose

abundance decreased substantially in SRSP. In 1957, Payne described U.

grandiflora as common (p. 28), whereas in the present flora, this species was

only observed in a few locations, often as small individuals. It is reasonable to

hypothesize that this decline is a result of deer finding this species very

palatable.

Deer can detect and avoid compounds that inhibit rumen microorganisms

and will avoid many plants that produce secondary compounds that can kill

bacteria (Rogers 1981). Additionally, the palatability of plants decreases as the

amount of secondary compounds they produce increases (Nagy et al. 1964,

Longhurst et al. 1968, Nagy and Regelin 1977). Some plant taxa that may be

characterized by their production of secondary compounds are Ranunculaceae,

Caryophyllaceae, Brassicales, Papaveraceae, and Berberidaceae (Judd et al.

2002). The ant-dispersed species examined that increased markedly belong to the families Berberidaceae, Papaveraceae, and Cyperaceae (Table 7). It is possible that these species increased in abundance rather than decreasing because of deer browsing preference. The secondary compounds found in species of Berberidaceae and Papaveraceae may cause them to be less palatable than other understory species present in the park.

The small changes in abundance of the remaining ant-dispersed species examined herein may only be due to a difference in intensity of study or rating of abundance between Payne and me. For example, some of the species that decreased in abundance one step include members of Papaveraceae, which

should be unpalatable because of secondary compounds. And two of those that increased a small amount are species of Trillium, which are known to be very palatable to deer. Trillium erectum was not noted by Payne (1957) but can be found in one location at present; it is possible that this species was merely overlooked in 1957, and is not actually increasing in abundance. Trillium sessile was noted as “apparently rare” (p. 29) by Payne, who only observed it in one location. Currently this species can be found in three locations.

The change in abundance of understory forest herb species is due to a complex interaction of many factors. If left undisturbed, ant-dispersed forest herbs with existing populations providing an adequate source of seeds should slowly increase in abundance, being able to spread about a meter every year.

However, today’s forests are rarely undisturbed, and over-browsing by deer may be an important factor in the decline of some ant-dispersed species. Additionally, not only does over-browsing by deer cause a decline in species diversity, but it can change the species composition of an area as well. For instance, in places where deer densities are high enough to cause over-browsing, the number of understory forb species decreases, while grass, sedge, rush and fern species increase (Coughenour 1985, Rooney and Waller 2003). In order to preserve the diversity of our natural areas, some form of deer population control is necessary.

In Ohio, the archery season for deer lasts from October through January, while gun season is a one-week period at the end of November or beginning of

December. This may not be enough to keep deer populations at a level that

won’t cause over-browsing. A Menominee Reservation in northern Wisconsin,

for example, allows year-round hunting, and this has helped to lower deer

densities. A 1988 study by Alverson et al. indicated that this Reservation is one of

the few places in Wisconsin where populations of Canada yew, a deer favorite, are

extensive and healthy. Lengthening the hunting season is only one way that the species diversity of SRSP can be preserved. An active, long-term deer

management plan appears necessary for the conservation of the forest

communities within the park.

Chapter V

Status of Medicinal Herb Populations in Strouds Run State Park

Introduction

Plants have been used as medicine all over the world since ancient times, and they often serve as a primary component of health care in rural and developing communities. Their beneficial uses have not gone unnoticed in industrialized countries, where more and more people are turning to natural herbal remedies to prevent or treat a variety of health conditions (Robbins 2000).

As a result, the demand for natural herbal remedies has increased continuously during the last two decades. The domestic herbal market boomed in the 1980s, with an estimated growth of 13-15% a year (Parsons et al. 2002). In 1993, the

U.S. exported 77 tons of wild ginseng alone, which grossed an estimated $21

million. The overall value of the U.S. market for medicinal herbs more than

doubled between 1996 ($1.6 B) and 1998 ($3.97 B) (Parsons et al. 2002).

Unfortunately, this boom, combined with a loss of the habitat that supports several medicinal herb species, has lead to the decline of many of these plants in the wild.

The most highly coveted medicinal herbs in Ohio are ginseng (Panax quinquefolius) and goldenseal (Hydrastis canadensis) (G. Scheider, staff botanist at ODNR, personal comm.). Other species in Ohio facing collecting pressure are

bloodroot (Sanguinaria canadensis), black cohosh (Cimicifuga racemosa), and

blue cohosh (Caulophyllum thalictroides) (Albrecht and McCarthy 2003).

The putative benefits of these herbs are many (Hoffman 1996). Ginseng

serves as an anti-depressant, nervine, stimulant, and overall tonic to increase

vitality. Goldenseal, too, has multiple uses. It has mild antibacterial action, and

is primarily used as a tonic for the mucous membranes of the body. Internally it

is used for digestive problems and externally for eczema, ringworm, pruritis,

earache, and conjunctivitis. Bloodroot demonstrates a relaxing action on the

bronchial muscles, and is used to treat bronchitis, asthma, croup and laryngitis.

Black cohosh is a powerful relaxant and a normalizer of the female reproductive

system and is used to treat menstruation and uterine problems. Blue cohosh is

another uterine tonic.

Ginseng’s range extends from Quebec and Manitoba south to Florida,

Louisiana, and Oklahoma (Anderson et al. 1993). An understory geophyte, it

prefers mesic sites in undisturbed forests, rarely growing in sunny places (Lewis

1988, Anderson et al. 1993). Plants of this species grow slowly, making them

particularly subject to extirpation if over-collected from the wild. Additionally,

most plants occur as separate individuals (Lewis 1984, pers. obs. 2003, 2004)

rather than clones, and they do not begin reproducing until they are at least four years old (Lewis and Zenger 1982, Lewis 1988, Anderson et al. 1993). This plant develops a solitary umbel, and each flower produces one to three seeds, which are enclosed in a pericarp that turns bright red when ripe (Gibbons 1966).

The fruits mature in the autumn, and the seeds usually are disseminated passively (Charron and Gagnon 1991, Anderson et al. 1993, Van der Voort et al.

2003), although they may be dispersed by rodents or other small animals (Van der Voort et al. 2003). Consequently, the seeds rarely germinate more than one meter from the parent plant (Anderson et al. 1993). The seeds require an after- ripening or dormancy of approximately 20 months before they will germinate

(Lewis and Zenger 1982). Seedling mortality is usually high, as shown by a study of a ginseng population in Missouri conducted by Lewis and Zenger (1982), where the probability that a seedling would give rise to an adult plant was only

0.55%. Ginseng is able to reproduce asexually through rhizome and root fragmentation (Van der Voort et al. 2003), but this has rarely been observed

(Lewis 1984). The pattern of occurrence as separate individuals and the infrequency of asexual reproduction by rhizome and root fragmentation suggest that ginseng relies mostly on sexual reproduction (Lewis 1988, Van der Voort et al. 2003).

Under normal forest conditions, ginseng plants do not produce a root that is harvestable until around 10 years of age (Charron and Gagnon 1991), and it is these mature plants that collectors usually dig (Anderson et al. 1993). In Illinois,

Anderson et al. (1993) showed that mature ginseng plants on unprotected sites produce 4.5 fruits/ha, whereas on protected sites they produce 24.6 fruits/ha.

They also showed that the removal of all 7-11 year old plants from a site results in a 68% loss in fruit production for that site. Because of over-collection in the

wild, ginseng was listed on Appendix II of the Convention for International Trade

on Endangered Species of Wild Fauna and Flora (CITES) in 1973 (Robbins

2000).

Goldenseal is an understory herbaceous perennial native to eastern North

America, ranging from Vermont to Michigan and Minnesota, and south to North

Carolina, Tennessee and Arkansas (Gleason and Cronquist 1998). It prefers

moist forest soils but is sometimes found in damp meadows (Robbins 2000,

Davis and McCoy 2001). Mature plants (3-4 years old) flower in the spring and

produce bright red berries by July (Davis and McCoy 2001). Unlike ginseng,

goldenseal can reproduce vegetatively. Spreading into surrounding areas

through the growth of fibrous roots and rhizomes, it usually occurs as relatively large clonal patches of interconnected plants (Robbins 2000, pers. obs. 2003,

2004). Seedlings have rarely been observed within these clonal patches

(Harding 1936, Sinclair and Catling 2000, Albrecht and McCarthy 2003). The

clonal growth habit combined with seedling rarity suggests that goldenseal relies

primarily on asexual reproduction rather than sexual reproduction (Van der Voort

et al. 2003).

Although goldenseal requires less time to mature and reproduces more

quickly than ginseng, this species is also susceptible to over-harvesting. The

high demand for this herb has caused a severe decline in native populations,

which was noticeable as early as 1884 (Davis and McCoy 2001). In 1997,

goldenseal was also listed on the CITES Appendix II treaty, and it is designated

as an endangered species in North Carolina (Davis and McCoy 2001, Van der

Vort et al. 2003).

Despite the CITES listing and trade monitoring of ginseng and goldenseal, states “neither routinely gather nor submit information on population status to the

USFWS” (U.S. Fish and Wildlife Service) (Robbins 2000, p. 1425). There has been no systematic, continuous monitoring of ginseng throughout its range

(Robbins 2000), although some field studies have been undertaken (Lewis 1984,

Charon and Gagnon 1991, Anderson et al. 1993). Continued monitoring of ginseng and goldenseal populations throughout their range could help determine the intensity and frequency of harvesting on wild populations and the effect of harvesting on population dynamics and regeneration of these highly valued plants.

Other widely used medicinal herbs native to Ohio, such as black cohosh, blue cohosh, and bloodroot, are currently not as threatened within the state as ginseng and goldenseal; however, illegal harvest has been documented in other states. For example, in 1998, 1,517 pounds of black cohosh roots were seized from a single pick-up truck along the Blueridge Parkway in Virginia (Nickens

2001). It can be expected that increased interest in the uses of these herbs

(Tarkan 2000, Zarrella 2004) will result in an increased demand for them, leading to a decline in abundance. Currently, the market value of black cohosh, blue cohosh and bloodroot is approximately $15 per dried pound, with bloodroot also bringing $3 per gallon pot as an ornamental (Nickens 2001). TRAFFIC North

America, a group working with The Nature Conservancy, identified 25 medicinal

plants potentially at risk from U.S. trade as priorities for further study (Robbins

1999). Black cohosh, blue cohosh and bloodroot were all on the list, and all

three are extensively collected in the Wayne National Forest in southeastern

Ohio (Larson 2003).

Effective management of forests where these beneficial plants are found,

together with cultivation to decrease the demand on native populations, will help

protect them (Das et al. 2001). The current inventory of the flora of SRSP can

determine the abundance of these herbs within the park and whether or not it has

changed over the last 50 years. This information could then be used to implement a monitoring program of populations within SRSP.

Methods

The abundance of at-risk medicinal herbs was noted as each was found

during the floristic survey of SRSP. The abundance rating assigned to each

species was compared to that recorded by Payne in 1957 to determine if there

has been any change. The location of these species was mapped and will be

given to park management so that the plants can be protected from disturbance

and, if possible, poaching.

Results and Discussion

Of the five medicinal herbs examined in this study, only Hydrastis canadensis underwent a substantial change (Table 8). Both black cohosh and bloodroot decreased in abundance one step, while blue cohosh and ginseng remained the same.

Table 8. The abundance of medicinal herbs in 1957 and their current abundance within SRSP, Athens, Ohio. Abundance Species Present 1957 Caulophyllum thalictroides Frequent Frequent Cimicifuga racemosa Frequent Common Hydrastis canadensis Frequent Rare Panax quinquefolius Rare Rare Sanguinaria canadensis Frequent Common

These results suggest that ginseng is being harvested from SRSP. Other

species with the same ecological requirements as ginseng, such as goldenseal

and some ant-dispersed species (Table 7) have increased substantially since

1957. This suggests that forest conditions are favorable for the growth of

ginseng. In addition, many seedlings emerge each year around plants in the

Strouds Run area that are reproductive (Cantino, pers. obs.), some of which

would be expected to survive to maturity. If the populations of ginseng plants

that were present in 1957 had been undisturbed since then, it stands to reason

that there would have been an increase in the abundance of this species.

Due to the value of goldenseal [$30 a pound in 2001 (Nickens 2001)], it is very probable that this herb is also being harvested from SRSP. The difference in abundance of ginseng and goldenseal within the park is likely the result of goldenseal’s ability to reproduce vegetatively.

Different methods are used to harvest ginseng and goldenseal. The most valuable ginseng roots are those that are large and intact, so diggers are careful to remove as much of the root from the ground as possible (Harding 1936, Van

der Voort et al. 2003). For goldenseal, on the other hand, no added value is gained by keeping the rhizomes intact (Van der Voort et al. 2003). Furthermore, the clonal growth form of goldenseal makes it difficult to remove all of the underground parts of these plants from the soil intact. Consequently, when diggers harvest goldenseal, “it is highly likely that portions of rhizomes and adventitious roots will be left at the site” (Van der Voort et al. 2003, p. 289).

A study in West Virginia by Van der Voort et al. (2003) examined the vegetative propagation potential of ginseng and goldenseal. They planted rhizome fragments, intact rhizomes and adventitious roots of goldenseal, and root fragments, intact rhizomes, and whole roots of ginseng in natural forested settings. They monitored the subsequent population over a four-year period and found that underground parts of both plants were capable of regeneration.

Almost half of all goldenseal propagules planted sprouted, and all types of propagules produced stems. Intact rhizomes and propagules from the distal portion of the rhizome had the highest rate of sprouting. One fourth of all goldenseal propagules planted produced reproductive stems, with intact rhizomes producing the most.

The sprouting status of ginseng propagules varied over the four-year period. All of the propagule types produced stems in at least one year, but only intact plants and whole root propagules sprouted in all four years. Van der Voort et al. (2003) discovered that rhizome and root propagules could remain dormant

up to three years after planting. Overall, more ginseng stems (both vegetative

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and reproductive) were produced by whole roots and root propagules than other types of propagules.

Van der Voort et al. (2003) also tested the potential recovery of goldenseal and ginseng after harvest. They were able to monitor the recovery of a naturally occurring goldenseal patch after it had been poached in 1995. After the harvest, only four plants remained. The following spring, 932 plants were present. Although the number of plants decreased slightly over the next three years, their size and the amount of flowering increased. The harvest of ginseng was conducted by the researchers, who were careful to gather all portions of roots from the study site.

Afterwards, they found that it behaved differently than goldenseal: before the harvest, there were a total of 23 plants, while the following spring only 11 plants were present. And while the number of plants recovered over the three-year period, their reproductive status changed dramatically. Before harvest, 78% of the plants were reproductive. But contrastingly, four years following harvest, less than

40% of the population were reproductive.

In 1979, a ginseng population marked for study in southwestern Missouri was decimated by diggers, leaving only one juvenile plant (Lewis 1988). Lewis followed the recovery of this population through 1984. After five years, 79% of the original population size had been re-established with individuals ranging in age from one to five years (based on annual rhizome bud scars). Lewis concluded that the majority of the recovered population developed from a pre- eradication seed bank at the site, because all but one of the plants at the site had

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been harvested, no other ginseng plants were observed for miles around, and rhizome fragmentation—and consequently asexual reproduction—is rarely observed in ginseng.

The apparent reliance of ginseng on its seed bank for recovery after harvest may explain why, in contrast to goldenseal, the abundance of ginseng in

SRSP has not increased since 1957. The long dormancy of seeds, high seedling mortality, extended juvenile period before plants become reproductive, and reliance on sexual reproduction all contribute to a slow recovery after harvest.

Even though Van der Voort et al. (2003) were able to show that asexual reproduction by root propagules is possible for ginseng, diggers rarely leave any root pieces behind. Conversely, the clonal growth habit of goldenseal and its ability to recover quickly after harvest (Van der Voort et al. 2003) could explain why it has increased significantly since 1957 even though it is very likely that this plant is being harvested from the park.

Another threat to the ginseng populations in SRSP is trail construction.

This observation is supported by findings from a study by Charron and Gagnon

(1991), who determined that a nearby footpath was detrimental to the ginseng population they were studying. Two of the four populations observed in the park are located adjacent to trails recently created by horse-back riders. Hikers also use these trails, and if they are widened even by a mere 12 inches, the ginseng plants could be trampled.

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The minor differences in abundance of black cohosh, blue cohosh and bloodroot between the current survey and 1957 (Table 8) may be artifacts of differences in the intensity of study and/or rating of abundance in the two studies.

However, other factors such as seed dispersal, deer herbivory, habitat restrictions, and illegal harvesting may play a role.

Black cohosh occurs on most mesic forested slopes within the park, making it readily accessible and highly susceptible to illegal harvesting. More generally, it is common in forested areas of southeastern Ohio. In a study of the distribution of medicinal plants in Wayne National Forest, black cohosh was the most abundant, occurring in 100% of study sites (Albrecht and McCarthy 2003).

This suggests that illegal harvesting of black cohosh has yet to have a detectable impact on naturally occurring populations in southeastern Ohio.

Bloodroot occurs frequently in Strouds Run and is easily located in most mesic ravines and stream terraces within the park. Bloodroot seeds are ant- dispersed (see Chapter IV) and may be slow to colonize previously unoccupied areas of the park. Additionally, herbivory by white tailed deer may be keeping these populations from increasing. The slight decline in the abundance of bloodroot within Strouds Run (Table 8) could be due to illegal harvesting, but further investigation is required in order to confirm this.

Within SRSP, blue cohosh seems to be restricted to ravines and stream terraces that are north or east-facing (pers. obs., M. Albrecht, pers. comm.) and it occurs frequently in these areas. Indeed, large populations of blue cohosh were

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often encountered in this study on steep, north-facing slopes. Furthermore, blue cohosh was found to be restricted to steep mesic slopes in southern

Pennsylvania (Bratton et al. 1994). While this species may not be as readily accessible as black cohosh and bloodroot, it is easily located and susceptible to harvesting; yet there was no apparent change in abundance detected in the two studies. This might indicate that illegal harvesting is not yet having an impact on the populations of blue cohosh in the park. The failure of blue cohosh to increase in abundance since 1957 (Table 8) may be due to a lack of additional suitable habitat within the park.

The medicinal herb species discussed here should be monitored and protected within SRSP. Areas that harbor populations of these plants should be regularly monitored for invasive plant species. If hiking trails are to be constructed near populations of these herbs, the plants should be relocated. If possible, equestrian traffic should be prohibited in these areas. This is especially true for ginseng because of its rarity within the park.

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Chapter VI

Influence of Stand Age and Environmental Factors

on Herbaceous Species Composition

Introduction

Logging, land clearance, and agriculture of the 18th and 19th centuries have transformed the landscape of eastern North America (Cronon 1983, Foster

1992, Motzkin et al. 1996). In Ohio, prior to European settlement, 95% of the state was forested (Backs 2003). By the 1840s, canal development, a successful iron industry, and agriculture led to a severe decline in forest cover. In the early

1900s, only 10% of Ohio (2.75 million acres) remained forested. However, by

1940, following the implementation of state forestry reserves in 1912 and farm abandonment after the Great Depression, Ohio’s forest cover began to rebound.

Today, more than 30% of the state is forested (Backs 2003). Forest regeneration has allowed researchers to study how forests recover from disturbance, and the factors that foster or hinder this recovery.

Aside from the well documented influence of land use history on woody species composition (Glitzenstein et al. 1990, Palik and Pregitzer 1992), the herbaceous layer of secondary forests is also affected by land use history. In both North American and Western Europe, there is a difference in species richness and species diversity between pre-settlement and post-settlement forests (Matlack 1994, Verheyen and Hermy

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2001, Verheyen et al. 2003a, 2003b). This may be due to the slow dispersal and colonization rates of many woodland herb species (Matlack 1994, Verheyen and

Hermy 2001).

Although dispersal limitations and colonizing abilities restrict some species to older forests (Verheyen and Hermy 2001), these are not the only factors that influence species diversity. Topography and the environmental variables associated with it also exert an influence on herbaceous species composition in secondary forests. For instance, north- and south-facing slopes differ greatly in temperature, light intensity, and moisture availability, creating notable differences in herb layer composition and structure (Wolfe et al. 1949, Huebner et al. 1995).

Small and McCarthy (2002a), working in an old-growth forest remnant in southeastern Ohio, found greater herbaceous species diversity in south-facing plots and greater herb abundance in north-facing plots. They also found that overall species composition varied with slope aspect. South-facing plots had greater graminoid abundance, while north-facing plots had greater forb abundance.

There are reasons to believe that land use history and environmental variables exert a combined influence on herbaceous species composition in secondary forests. In the Hudson Valley of New York, differences between forests on formerly cultivated land and uncultivated land were shown to be the result of the interplay of environmental and historical factors (Glitzenstein et al.

1990). Not only did land use history explain compositional differences, but also

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structural and environmental differences. Previously cultivated land supported

more stratified forests, had lower soil nutrient levels, and had more old-field

species in the understory than forests on uncultivated land.

The purpose of the current study is to compare the relative importance of

natural and anthropogenic factors on the herbaceous species composition of secondary forests within SRSP. Comparing the herbaceous composition of differently aged stands provides insight into which environmental factors influence species composition during the later stages of secondary forest colonization. Factors such as slope aspect, the amount of canopy cover, and the amount of litter on the forest floor, in addition to more frequently examined factors such as soil moisture and soil nutrient content, could influence species’ ability to become established at a site and their ability to survive and reproduce there (Sydes and Grime 1981, Verheyen et al. 2003a). In addition, disturbances such as canopy removal and agricultural practices result in long term environmental changes, affecting herbaceous species composition (Palik and Pregitzer 1992,

Motzkin et al. 1996, Verheyen et al. 1999).

Knowledge of long-term forest succession and the history of land use are valuable for managing forest diversity. Stand age is a potential indicator of which land should be acquired and preserved. An understanding of the historical effects on species communities can allow researchers and managers to better anticipate future outcomes of long-term management practices (Matlack 1997).

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In this study I examined the herbaceous species composition of differently

aged stands and stands with different canopy composition within SRSP. Initial

observations indicated that species composition (both woody and herbaceous)

differed depending on whether the community observed was on top of a ridge or

in a valley. Mixed oak forests dominate upland areas, while mixed mesophytic

forests dominate lowland areas. Historical aerial photos indicate that some parts

of the park have been densely forested since 1950, while the rest of the park was

either completely cleared of trees in 1950 or had sparse forest cover at that time.

My objectives were: (1) to determine if the composition of the herbaceous

species communities in SRSP differs significantly between mixed oak and mixed

mesophytic forests; (2) to determine if the composition of the herbaceous species

communities differs between old forests (>65 years) and young forests (≤ 40) in

order to interpret changes in community composition over time; and (3) to

determine if environmental factors that vary between forest type (litter cover, litter

depth, canopy cover, percent slope, and the amount of exposed rock) and landscape position (north vs. south) have any influence on herbaceous species communities in SRSP.

Materials and Methods

Field sampling

The area was subjectively divided into community types based on visual estimates of canopy dominance following the community classification of unglaciated Ohio by Cusick and Silberhorn (1977). If most canopy trees were

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oak species, the stand was considered “mixed oak.” If the tree canopy was a

mixture of tulip poplar, sugar maple, ash, and buckeye, the stand was considered

“mixed mesophytic.” Forest age was determined using aerial photos from 1939,

1950, 1963, and 1970. Forest sites that were field or pasture in 1950 had

developed a shrub layer by 1963, and the canopy had closed by 1970. These

areas were considered young woods (estimated age 33-40 years), while areas

that had a completely closed canopy in 1939 were considered old woods (age

>65 years). Classification of sloped sites was based on slope aspect [north-

facing (includes northeast and northwest) or south-facing (includes southeast

and southwest)] and landscape position (ridge top or valley bottom) as

determined using a topographic map; these parameters were subsequently

confirmed on site. Using these parameters, seven community types were

chosen for sampling: mixed oak ridge south-facing, mixed oak ridge young

woods, mixed oak ridge old woods, pine plantations, mixed mesophytic bottomland young woods, mixed mesophytic bottomland old woods, and mixed

mesophytic north-facing. Five 10-m diameter circular plots were established in

each of these community types, for a total of 35 plots.

In order to identify as many of the species present as possible, plots were

surveyed three times during the growing season in 2003: May, July, and

September. Only herbaceous species, subshrubs (e.g. Rubus flagellaris) and

vines (e.g. Parthenocissus quinquefolia) were sampled at each plot. Trees and

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shrubs were excluded. Percent cover was estimated for each species (species

estimated to have <2% in cover were arbitrarily given a 2% cover value).

The percent cover of leaf litter in each plot was visually estimated, and litter depth was measured (in cm) at eight points 2 dm in from the edge of the

plot. The mean of the eight measurements was used for subsequent analysis.

Slope gradient in each plot was measured as a percent using a Suunto clinometer (Suunto Co., Helsinki, Finland). To estimate the relative light in each plot, the canopy cover (forest overstory density) was determined using a spherical densiometer. Four readings were made in each plot: north, east, south,

and west, and their mean was used for subsequent data analysis.

Data analysis

Species compositional patterns were analyzed for all plots using non-

metric multidimensional scaling (NMS) ordination. Unlike other commonly used

ordination techniques, NMS is non-parametric and iterative (Clarke 1993). NMS

ordination rectifies some of the flaws of PCA and DCA by maximizing the rank

order correlation. It creates an initial configuration of samples in N dimensions.

A measure of “stress” (the amount of difference between the rank order of

distances in the data and the rank order of distances in the ordination) is

calculated. The samples are then moved slightly in a direction that decreases

the amount of stress. Measuring stress and moving the samples are repeated

until the amount of stress reaches a minimum (Clarke 1993). NMS has been

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shown to perform well with non-normal ecological data containing numerous zero

entries (McCune and Grace 2002).

NMS ordinations were performed with PC-ORD (v. 4, McCune and

Mefford 1997) using Sorenson distance. The first ordination was performed

using the greatest amount of cover recorded for each species encountered at

each plot at any date during the study (hereafter referred to as the Total Species

ordination). Ordinations were also performed using the amount of cover

recorded for each species present at each plot in May, July, or September

(hereafter referred to as the May, July, or Sept. ordinations).

Correlations of the measured environmental variables and observed

species for each community type to the NMS axes were determined using PC-

ORD. The p-values for the correlation coefficient were obtained from a table of

critical values (Zar 1999).

To determine how similar species composition was between plots in the

same assigned community type, a cluster analysis was done on the data from

the Total Species ordination using PC-ORD (v. 4, McCune and Mefford 1997).

Cluster analysis is a process of identification and categorization of subsets of objects that are continuously distributed. The primary purpose of this is to describe the structure of a continuum and identify various objects types (McCune and Grace 2002).

Differences in species richness and species diversity between different community types were assessed by comparing the observed species richness

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(S; number of species per sample), Shannon-Wiener diversity [H' = -Σpi lnpi,

where pi is the proportion of individuals in the ith species (Shannon and Weaver

(1963)], and mean species cover per plot. Percent cover estimates were used in the calculation of H', and the mean and standard deviation for each environmental variable at each plot were calculated. All diversity calculations were performed using NCSS (Hintze 2000). To detect significant differences in environmental variables between community types, Kruskal-Wallace tests were performed using NCSS.

Results

A total of 166 species were found in the 35 sample plots. The most frequent of these were Parthenocissus quinquefolia, Galium aparine, unidentified grasses, Elymus hystrix, Polystichum acrostichoides, Osmorhiza claytonii, and

Aster spp. which appeared in 31, 28, 26, 24, 21, 21, and 20 plots respectively.

Forty-nine species only appeared in one plot. Eighty-one percent of the 166 species recorded occurred in 10 or fewer plots, while only 10% of the species occurred in 15 or more plots.

There were significant (p < 0.05) differences in litter cover, litter depth, and canopy cover in the communities sampled, while slope and exposed rock were not significantly different (Table 9). Mesic old stands and pine plantations had significantly more litter cover than mesic young stands (Table 9). Pine plantations had the greatest depth of litter, while young mesic stands had the least depth of litter. The most striking difference in the amount of canopy cover

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was between old and young mesic woods (Table 9). Canopy cover is significantly different between age classes when both communities are considered together.

Table 9. Mean measurements of litter cover, litter depth, canopy cover, slope, exposed rock, species richness, species diversity, and species cover in each of five community types sampled in SRSP. Significant differences are indicated by the letters following each measurement. Items with different letters are significantly different (p < 0.05) from each other. * Significantly different when only age is considered. Environ. Factor Mesic Old Mesic Young Oak Old Oak Young Pine Litter Cover (%) 98.13a 70.83b 90.29ab 98ab 100a Litter Depth (cm) 1.99ab 1.55a 2.35bc 2.08ab 2.58c Canopy Cover (%) 91.1a* 80.28b* 87.56ab* 86.03b* 83.05b Slope (%) 5.75 4.82 10.54 7.76 10.1 Exp. Rock (%) 1.9 0 3 1.13 0 Spp. Richness (S) 30.75a 34.33a 19.29b 18b 28.6ab Spp. Diversity (H') 2.92 3.02 2.81 2.64 3.1 Herb Cover (%) 67.88bc 124.92c 23.95a 35.57ab 67.77bc

Species parameters also showed some differences between stands analyzed. Species diversity did not differ significantly among the communities, but species richness was higher in mesic stands than in oak stands. Herb cover was greatest in young mesic woods, while old oak stands had the lowest herb cover (Table 9).

Differences in environmental variables between community types in each sampling season were generally similar to the overall differences (Table 10). For this reason, the remainder of this study focuses on the overall pattern rather than seasonal patterns. However, differences in species diversity show in particular

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seasons, but not in the overall analysis (Table 9 and 10). This is most apparent in May, but becomes much less so as the growing season progressed.

Litter Cover (%) Litter Depth (cm) Canopy Cover (%) Community May July Sept. May July Sept. May July Sept. Oak Old 89.57 88.57a 86.43a 2.15ab 2.00b 1.8b 84.03 87.26a 82.84 Oak Young 96.43 91.29ab 93.57a 2.01a 1.67b 1.77b 82.88 83.77ab 82.17 Mesic Old 97.75 96a 90.63a 1.98a 1.40ab 1.23a 85.41 90.28a 85.05 Mesic Young 55.00 60.8b 41b 1.51a 0.90a 0.86a 72.49 73.95b 75.82 Pine 95.60 100a 100a 2.54b 1.80b 2.0b 79.36 81.75ab 79.51

Species Richness (S) Species Cover (%) Species Diversity (H') Community May July Sept. May July Sept. May July Sept. Oak Old 13b 9.43c 8.43b 29.29c 23.29b 19.29a 0.9b 0.77c 0.59c Oak Young 12.71b 10.14bc 9.71b 42.43bc 33.71ab 30.57ab 1.06b 0.95bc 0.8bc Mesic Old 21.25a 17.38a 15.75a 103.88ab 57a 42.75bc 2.28a 1.66a 1.25ab Mesic Young 23.8a 15abc 16.8a 194.58a 70.67a 97.17c 3.52a 1.54ab 1.66a Pine 18.6ab 16ab 18.2a 94.5ab 54a 54.8c 2.07a 1.45ab 1.47a

Composition of the herbaceous communities differed between forests with different canopy types and between stands of different ages within each canopy type. The NMS ordination of 35 plots using the Total Species data showed a partial separation of plots into three community types: mixed oak, mesic, and pine plantation (Figure 14). Plots in pine plantations grouped together but overlapped the mesic plots’ cluster. Differently aged stands also showed some separation, particularly when oak stands are compared (Figure 15). Unlike the

Total Species NMS ordination, the May, July, and September NMS ordinations

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revealed no clear separation of community types (Figures 16-18). The percent

variance explained by each NMS Axis, the final stress, and the final instability for

each of the four ordinations are presented in Table 11.

Species composition differed between mesic woods and oak woods

(Figure 14). Abundance of several species was significantly (p < 0.05) correlated with one of the three NMS Axes in one of the four ordinations (Table 12).

Table 11. Percent variance explained by each Axis, final stress, and final instability for four ordinations performed on species abundance data collected from SRSP. All ordinations were best fit by a three-axis solution, as determined by Monte Carlo randomizations tests (p = 0.02 in each case). Variability (%) Ordination Total Axis 1 Axis 2 Axis 3 Final Stress Final Instability Total Species 80.5 16.6 50.1 13.3 13.49 0.0008 May Species 68.8 23 18.9 26.9 16.69 0.0005 July Species 71.3 28.4 24.1 18.7 18.34 0.0015 Sept. Species 75.7 41.4 16.9 17.4 16.85 0.0112

Species such as Arisaema triphyllum, Polygonum virginianum, Pilea

pumila, and Ranunculus abortivus were often encountered in mesic woods, while

Porteranthus stipulatus, Panicum lanuginosum and Cunila origanoides were

particularly characteristic of oak woods (Table 12). Another species

characteristic of oak woods that is worth noting is the orchid Goodyera

pubescens (r = -0.49, p < 0.05). Young woods had a greater abundance of annuals, grasses, and sedges such as Galium aparine, Stellaria media, Elymus

hystrix, Poa spp., and Carex laxiculmis (Table 12). These abundances were

based on overlays of species abundance on the ordination graph.

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Table 12. Species that were significantly correlated (p < 0.05) to at least one of the Axes in one of the four ordinations performed, and had an r value ≥ 0.5.

NMS Axis Species r Comm. Type 1 2 3 Ordination Arisaema triphyllum 0.65 Old Mesic x Total 0.52 x July Carex laxiculmis -0.53 Young Mesic x Total Cunila origanoides -0.57 Oak Woods x Total -0.53 x July 0.58 x Sept. Elymus hystrix -0.62 Young Woods x Total Galium aparine 0.62 Young Woods x Total -0.53 x Sept. Galium lanceolatum 0.56 Mesic Woods x May Porteranthus stipulatus -0.54 Oak Woods x May Graminoids -0.58 Young Woods x Total 0.61 x July Osmorhiza claytonii 0.53 Mesic and Pine x Total 0.53 x May Panicum lanuginosum 0.54 Oak Woods x Sept. Parthenocissus quinquefolius 0.51 Pine Plantations x Total Pilea pumila 0.55 Mesic Woods x Total Polystichum acrostichoides 0.52 Mesic and Pine x Total 0.60 x May 0.59 x July Poa spp. -0.57 Oak & Young Mesic x May Polygonum virginianum 0.50 Mesic Woods x Total 0.56 x May Ranunculus abortivus 0.67 Mesic Woods x Total Sanicula canadensis -0.52 Mesic and Pine x Sept. Sedum ternatum 0.56 Old Mesic x Total -0.65 x Sept. Stellaria media 0.59 Young Mesic x Total -0.58 x Total 0.52 x May Verbesina alternifolia -0.53 Young Mesic x Total 0.53 x Total -0.52 x July -0.50 x Sept. Viola spp. 0.51 Mesic Woods x Total -0.57 x Sept.

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In the Total Species ordination, Axis 1 was positively correlated with litter cover, litter depth and canopy cover (Table 13). In the May Species ordination,

Axis 2 was positively correlated with litter depth and canopy cover and Axis 3 was positively correlated with litter cover. In the July Species ordination, Axis 1 was positively correlated with litter depth and Axis 2 was negatively correlated with litter depth. In the September Species ordination, Axis 1 was positively correlated with litter depth, Axis 2 was positively correlated with canopy cover, and Axis 3 was negatively correlated with litter cover and litter depth (Table 13).

Table 13. Correlations of the measured environmental variables with the first three Axes for each NMS ordination.

Correlation Coefficient Ordination Variable Axis 1 Axis 2 Axis 3 Total Litter Cover 0.451* -0.118 -0.266 Litter Depth 0.44* -0.262 -0.007 Canopy Cover 0.498* 0.028 -0.322 Slope 0.299 -0.188 -0.078 Exp. Rock 0.169 -0.108 -0.182 May Litter Cover 0.016 0.299 0.401* Litter Depth 0.094 0.346* 0.101 Canopy Cover 0.076 0.344* 0.315 Slope -0.064 0.188 0.067 Exp. Rock -0.050 0.075 0.189 July Litter Cover 0.127 -0.025 0.260 Litter Depth 0.416* -0.389* 0.085 Canopy Cover 0.125 -0.016 0.237 Slope 0.133 -0.136 0.048 Exp. Rock 0.059 -0.186 0.015 September Litter Cover 0.149 0.285 -0.484* Litter Depth 0.389* 0.228 -0.364* Canopy Cover -0.089 0.438* -0.317 Slope 0.323 0.066 -0.319 Exp. Rock 0.262 -0.008 -0.119 * Significant at p < 0.05

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The cluster analysis defined three groups of plots. Group 1 mostly consisted of plots in mesic woods and pine plantation, but also contained a few plots in oak woods. Plots in group 2 were all in oak woods, while group 3 contained only plots in mesic woods (Figure 19). Plot 7 (pine plantation), 34

(young mesic), and 17 (mesic north-facing) came out separately in the cluster analysis and were not associated with any of the groups (Figure 19). The cluster analysis groups fit the NMS ordination of Total Species when plotted on it (Figure

20).

An outlier that warrants discussion is plot 17. Plot 17 lies far outside the three primary clusters in ordination space (Figure 20). This plot was originally designated as a north-facing mesic plot, but it was later re-classified as an old mesic plot. There are no physical differences between this and any of the other mesic plots. The difference may lie in the plot’s species richness and not necessarily its composition. Mesic plots averaged 35 herbaceous species, but plot 17 had only four. Most of the herb layer in this plot was composed of the seedlings of trees and shrubs such as Acer spp. and Sassafras albidum. While herbaceous species account for the majority of species in deciduous forests

(McCarthy 2003, Whigham 2004), they are the most spatially dynamic forest plants (Gilliam and Roberts 2003), and their distribution on the floor of mature forests in SRSP is often sparse (pers. obs.). An explanation for plot 17’s low species richness may be competition of the herb layer with the large number of tree seedlings.

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Slope aspect had less influence on herbaceous composition than did

stand age. Plots on north or south-facing slopes did not cluster separately from

non-slope plots within the same community type in the NMS ordination (Figure

22). Nor did these plots group together in the cluster analysis (Figure 19). The

only significant differences between slope and non-slope were litter depth in

mesic woods and exposed rock in mesic and oak woods (Table 14). Using the

1950 air photos, north or south-facing slopes were re-assigned as young or old

stands. This resulted in a clear separation of young from old within each

community type (Figure 21), if two unusual plots (discussed below) are ignored.

In addition to the initial five plots, there was a gain of two plots for old oak, two

plots for young oak, one plot for young mesic and three plots for old mesic. The

age of two of the plots [one mesic north-facing (plot 13) and one oak south-facing

(plot 29)] was uncertain from the aerial photo, so they were ignored for the

remainder of the young vs. old analysis.

Some plots did not fit the general pattern observed. Plot 33 was assigned

as a young mesic plot, but it clustered with the old mesic plots (Figure 21). The

reason for this might be this plot’s location. Plot 33 was in young woods on a

ridge, while the remaining young mesic plots were located in valleys. This

location difference may have caused the species composition of plot 33 to differ

from the other young mesic plots. Perhaps a ridge location had less soil moisture than the other young mesic plots, resulting in slower rates of

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decomposition and increased litter accumulation, or there could be unmeasured variables at play such as soil chemistry.

Another plot that did not fit the pattern was Plot 2, a mesic old plot that clustered with the mesic young plots. During the July survey, it appeared to have been recently flooded. This plot was located closer to a stream than the other old mesic plots, and perhaps periodic natural disturbance from flooding may explain the higher abundance of annuals and the lack of woodland perennials such as Arisaema triphyllum and Polygonum viriginianum that are present in the other old mesic plots.

Table 14. Mean measurements of litter cover, litter depth, canopy cover, slope, exposed rock, species richness, species diversity, and species cover in slope and non-slope plots sampled in SRSP. Mesic Oak Environ. Factor N-facing Non-slope S-facing Non-slope Litter Cover (%) 100 87.33 88.8 94.4 Litter Depth (cm) 2.15* 1.82 2.28 2.21 Canopy Cover (%) 87.94 86.51 83.1 86.74 Slope (%) 6.04 5.39 7.54 9.06 Exp. Rock 0* 6.17 8.5* 2.5 Spp. Richness (S) 25.6 35 16 19.9 Spp. Diversity (H') 2.71 3.11 2.61 2.77 Spp. Cover (%) 64.43 103.6 24.8 30.2

* Significantly different at p < 0.05

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2.0

1.5 MPlot 17

O 1.0 O

O O O O O 0.5 O O

O P O O O M 0.0 P M M MM Axis 2 P M M M P O M -0.5 P

-1.0 M

P Pine Plantation M -1.5 M M Mesic Woods O Oak Woods

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

Axis 1

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1.5

OO 1.0

OO OO OO 0.5 OY OO

OY MO 0.0 MY MO

MY MO

Axis 2 OY MO -0.5

MY -1.0

OO Oak Old MO OY Oak Young MO Mesic Old MY -1.5 MY Mesic Young MY

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0

Axis 1 Figure 15. NMS ordination as in Figure 14, with pine plantations removed and showing differently aged mesic and oak plots. Plots on slopes are not shown.

122

1.5 O Oak Woods M Mesic Woods M P Pine Plantation M 1.0 M M M M M 0.5 MM M O P P O P M P 0.0 M O O Axis 3 Axis P M O O O O O -0.5 O O O O O M O -1.0

M Plot 17

-1.5 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 Axis 1

Figure 16. NMS ordination of the amount of cover recorded for each species at each plot during the May survey of community types in SRSP. Differently aged plots are not distinguished.

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1.5 Plot 17

1.0

O O O

M O 0.5 O O O O O M O M Axis 2 O 0.0 M P M M O M M P M O P M O Oak Woods M M -0.5 M M Mesic Woods O P Pine Plantation P M M P

-1.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

Axis 1 Figure 17. NMS ordination of the mount of cover recorded for each species at each plot during the July survey of community types in SRSP. Differently aged plots are not shown.

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1.0 Plot 17 O M 0.8 O

O 0.6 M O

M 0.4 M M M

0.2 M M M M P P O P O O 0.0 O Axis 3 Axis M P -0.2 M O

M P -0.4 O O M

-0.6 O Oak Woods M Mesic Woods P Pine Plantation O -0.8 M O O O -1.0 -1.0 -0.5 0.0 0.5 1.0 1.5

Axis 1 Figure 18. NMS ordination of the amount of cover recorded for each species at each plot during the September survey of community types in SRSP. Differently aged plots are not distinguished.

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Group 1

Group 2

Group 3

126

2.0

Plot 17 1.5 M

O 1.0 O

O O O O O O 0.5 O O O P O O O M 0.0 P M M Plot 7 MM Axis 2 P M M M P O M -0.5 P Plot 34 M

-1.0 M

O Oak Woods M M Mesic Woods M -1.5 P Pine Plantation M

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

Axis 1 Figure 20. NMS ordination as in Figure 14, with groups from the cluster analysis depicted. Differently aged plots are not distinguished.

127

2.0

1.5 MO Plot 17

OO 1.0

OY OO OO OO OO Plot 33 OO 0.5 OY OO OY OY OY OY MO 0.0 MO MY MOMO Axis 2 MY MO OY MO -0.5

-1.0 MY Plot 2 MO OO Oak Old MY -1.5 OY Oak Young MO Mesic Old MY MY Mesic Young

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0

Axis 1

Figure 21. NMS ordination as in Figure 14, after north or south-facing plots were re-assigned as young or old plots; pine plantations are not shown. Plot 2, 17, and 33 did not sort out as expected.

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2.0

1.5

O 1.0

O O O 0.5 O O P O O M 0.0 P M M Axis 2 P M M P O M -0.5 P

M -1.0 O Oak Woods M Mesic Woods M P Pine Plantations M -1.5 ▲ Mesic North-facing M ▼ Oak South-facing

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

Axis 1 Figure 22. NMS ordination as in Figure 14, depicting plots on slopes. Note how the sloped plots do not group with each other. Differently aged plots are not distinguished.

129

Discussion

Previous studies have shown that environmental factors affect the

composition of the forest overstory. In south-central Ohio, parent soil material

and topographic position were the major environmental factors related to species

distribution of woody plants (Anderson and Vankat 1978). McCay et al. (1997), working in eastern West Virginia, found that woody vegetation patterns were strongly associated with elevation. They found that higher elevations of the

Allegheny Mountains were cooler and moister than Ridge and Valley locations.

However, the present study focuses on herbaceous species composition, and the findings suggest a correlation with the overstory (Figure 14). Since herbaceous species composition differs between mesic woods and oak woods in this study, the environment may also be affecting the herb layer.

Alternatively, the composition of the canopy itself may be directly affecting the herb layer. A study in Hocking County , Ohio reported that the stem flow (the portion of the precipitation intercepted by the canopy and reaching the ground by running down the branches and trunk) of Quercus alba had higher concentrations of calcium and sulfate ions and lower concentrations of hydrogen ions than other trees in the study area (Crozier and Boerner 1984). The soils around Q. alba trees had significantly higher concentrations of the above-mentioned ions and lower pH than soils around other trees (Crozier and Boerner 1984). Such differences in soil chemistry resulting from canopy composition may also explain

130

the differences in herb layer species composition between different community

types in SRSP.

The difference in species richness between mesic woods and oak woods

may be explained by a difference in the amount of moisture in each community

type, which is consistent with the findings of previous studies conducted in Ohio.

A greater species richness and herb cover in moister, lower-slope positions was

found in another study in southeastern Ohio (Small and McCarthy 2002a).

Hutchinson et al. (1999) also found a greater herb layer species richness and

greater species cover in moist, lower slope positions in second-growth oak forests

in southern Ohio. Huebner et al. (1995) found a positive correlation between slope

aspect and species diversity, and they concluded that moister, north-facing slopes support a greater number of species. Olivero and Hix (1998), working in southeastern Ohio, also found that species richness differed significantly between dry and moist sites.

In the present study, herbaceous species composition also differed between differently aged stands (Figure 15), and the results suggest that this may be due to environmental differences between old and young mesic woods.

Old mesic woods had more litter cover and more canopy cover than young mesic woods (Table 9).

Litter accumulation has been shown to inhibit seedling recruitment

(Eriksson 1994) and to have a negative effect on species richness (Xiong and

Nilsson 1999). This implies that secondary forest communities with a deep litter

131

layer should be colonized more slowly and have fewer species than those with

less litter. Sydes and Grime (1981), working in the British Isles, found that as the

amount of litter weight increased, total shoot biomass of woodland herbs

decreased, implying that increasing amounts of litter could decrease the amount of herbaceous cover. The results of the present study indicate a similar pattern.

In mesic woods, old stands had more litter cover and less species cover than young stands (Table 9).

The amount of light available to woodland herbs is generally a function of canopy closure (Gilliam and Turrill 1993), and it has been shown by several studies that increases in the amount of light reaching the forest floor results in increasing the species richness of the herb layer (Menges 1986, Meier et al.

1995, Motzkin et al. 1996). In the present study, young mesic woods have less canopy cover than old mesic woods (Table 9). This finding suggests that herbaceous communities in young mesic woods are receiving more light than those in old mesic woods and should therefore have more species than old woods. While there was no significant difference in species richness between old and young mesic woods, the composition of the herb layer in young and old mesic woods differed (Figure 21), implying that light is also affecting the herb layer in SRSP.

The grouping of pine plantations with old mesic stands (Figure 23) is unexpected, considering that pine stands are young forests planted ca. 1950.

The answer may lie in the effect of litter accumulation. Pine plantations had

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2.0

Plot 17 1.5 MO

* 1.0 *

* * * * * * 0.5 * * * P * * * MO P 0.0 MO * MOMO Axis 2 Axis P * * MO P * MO -0.5 P

-1.0 * MO Mesic Old P Pine Plantation MO * Mesic Young, Oak Old, * -1.5 and Oak Young *

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 Axis 1 Figure 23. NMS ordination as in Figure 14, depicting pine plantations and old mesic stands.

the same amount of litter cover as old mesic stands, and a greater percentage of litter cover than young mesic stands (Table 9). Additionally, pine plantations had deeper litter than mesic woods (Table 9). Because litter accumulation has been shown to inhibit seedling recruitment (Eriksson 1994) and lower herb biomass

(Sydes and Grime 1981), pine plantations should have less herb cover than stands with lower amounts of litter. In SRSP, pine plantations have similar amounts

133

of herb cover as mesic woods (Table 9). The similarity in the amount of litter cover and herb cover between pine plantations and mesic stands suggests litter accumulation may be an important factor influencing species composition in mesic woods.

The ordination results of this study clearly show a difference in species composition between old and young oak woods (Figure 15). However, none of the measured factors differed significantly between these types of stands (Table

9). Other unmeasured environmental variables such as soil texture and chemistry may differ between old and young oak stands, contributing to the observed differences in species composition. Such differences were found in a mixed hardwood forest in western Belgium (Verheyen et al.1999), where a positive correlation was found between duration of arable land use and soil pH, calcium and phosphate content, and a negative correlation between the duration of land use and carbon content, total nitrogen content, and the C:N ratio.

Conclusion

Land use history is still evident in the herb layer community of the second growth forest stands of SRSP years after canopy closure. Stand age appears to influence the environment in mesic woods, but not in oak woods. While older stands in SRSP are not more species-rich than young stands, this study revealed differences in species composition. Having additional time for forest development and species dispersal may begin to reduce the impacts of land use history. Unfortunately, the exact age and land use history of the old stands in

134

SRSP are unknown. Depending on the extent of previous disturbance, these areas may have acted as a refuge for slow colonizing woodland herb species, or they may have had more time to be colonized from other sources. The age difference also allowed for more litter accumulation and canopy closure in mesic forest stands. These changes create an environment that is darker, and presumably moister and cooler, than secondary woods < 40 years old. This type of environment is more conducive to the growth of woodland herbs of interest such as those with medicinally active components or those facing habitat loss

(Whigham 2004). The management implications, therefore, should include protection of secondary stands of any age from disturbance and invasive plant species. Given enough time, such stands could begin to support an herbaceous species composition similar to primary forests.

135

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159

Appendix 1:

Terrestrial vascular plant species documented at Strouds Run State Park, Athens

County, Ohio

The list is arranged alphabetically within major divisions. Species nomenclature and native/non-native status follow Cooperrider et al. (2001), but casual vs. naturalized is based on my observations in the park. Family classification of seed plants follows Judd et al. (2002) and Beardsley and Olmstead

(2002); family classification in Lycophyta, Sphenophyta and Pterophyta follows FNA

(1993). For the most part, varieties are only recognized as such when a taxon classified as a species by Gleason and Cronquist (1991) was classified as a variety

by Cooperrider et al. (2001). In addition, taxa included here that were not included

by Cooperrider et al. (2001) are Picea glauca and Bromus racemosus. Author

abbreviations follow Brummitt and Powell (1992). Species preceded by an asterisk

(*) are naturalized aliens, species preceded by a dagger (†) are casual aliens (see

Chapter III), and species preceded by a (#) are native in southern Ohio but

naturalized in the park. Recent ornamental plantings (e.g., Spiraea sp. and Thuja

sp.) are not included in the checklist. Tsuga canadensis, while probably planted at

some point in the past, was not planted by park management, so is here treated as

a native species. Species preceded by a ‘PT’ are listed as “potentially threatened”

within the state of Ohio (ODNAP 2000). An abundance rating of common (4),

160

frequent (3), infrequent (2), and rare (1) (see Chapter II) is given to each species;

(?) was used for species that could not be distinguished in the field. Every habitat or community type where a species was observed is indicated as follows: old field

(F), lawns and regularly mowed areas (L), marshes and lake edge (M), mixed oak woods (OW), prairie-like openings (PO), pine plantations (PP), rock outcrops (R), stream terraces and ravines (SR), and young woods (approximately 30 years since canopy closure) and disturbed areas including roadsides and trail edges (YD).

Finally, the collection number(s) are given. All collections were made by the author.

Voucher specimens are deposited at the Bartley Herbarium at Ohio University.

161

Appendix 1

Terrestrial vascular plant species documented at Strouds Run State Park, Athens County, Ohio University

Abundance & Habitat Collection # LYCOPHYTA LYCOPODIACEAE Diphasiastrum digitatum Dill. ex A. Braun 3 OW PP SR 665 Huperzia lucidula (Michx.) Trevis. 2 OW SR YD 11 Lycopodium obscurum L. 1 OW 244

SPHENOPHYTA EQUISETACEAE Equisetum arvense L. 3 M SR YD 98 Equisetum hyemale L. 2 M SR YD 668

PTEROPHYTA ASPLENIACEAE Asplenium pinnatifidum Nutt. 1 R 245 Asplenium platyneuron (L.) Britton, Sterns, & Poggenb. 3 OW PP SR YD 249, 608 Asplenium rhizophyllum L. 2 R 12, 118 Asplenium trichomanes L. 1 R 607

DENNSTAEDTIACEAE Dennstaedtia punctilobula (Michx.) T. Moore 2 SR 255, 720

162

Abundance & Habitat Collection # DRYOPTERIDACEAE Athyrium filix-femina (L.) Roth ex Mert. 2 SR 407, 728 Cystopteris protrusa (Weath.) Blasdell 3 SR 248, 263, 264 PT Cystopteris tennesseensis Shaver 1 SR 243 Deparia acrostichoides (Sw.) M. Kato 3 OW PP SR YD 725 Diplazium pycnocarpon (Spreng.) M. Broun 2 SR 528, 610 Dryopteris carthusiana (Vill.) H.P. Fuchs 3 PP SR 153, 241 Dryopteris goldiana (Hook. ex Goldie) A. Gray 2 SR 225, 336 Dryopteris intermedia (Muhl. ex Willd.) A. Gray 4 PP SR 220, 256 Dryopteris marginalis (L.) A. Gray 2 SR 666 Onoclea sensibilis L. 3 M SR YD 729 Polystichum acrostichoides (Michx.) Schott 4 OW PP SR YD 221, 250

OPHIOGLOSSACEAE Botrychium dissectum Spreng. 3 OW SR 254, 605 Botrychium virginianum (L.) Sw. 3 OW SR 223, 247 Ophioglossum vulgatum L. 2 SR 91

OSMUNDACEAE Osmunda claytoniana L. 2 SR 246

POLYPODIACEAE Polypodium virginianum L. 3 R 89

163

Abundance & Habitat Collection # PTERIDACEAE Adiantum pedatum L. 3 SR 486 Pellaea atropurpurea (L.) Link 1 R 257

THELYPTERIDACEAE Phegopteris hexagonoptera (Michx.) Fee 3 SR 604 Thelypteris noveboracensis (L.) Nieuwl. 2 SR 609

CONIFEROPHYTA CUPRESSACEAE Juniperus virginiana L. 2 F YD 646 † Taxodium distichum (L.) Richardson 2 SR 560 PINACEAE † Larix sp. 1 SR 649 † Picea glauca (Moench) Voss 1 SR 634 † Pinus nigra Arn. 3 PP 653 † Pinus resinosa Aiton 4 PP YD 635 # Pinus strobus L. 4 OW PP YD 636 † Pinus sylvestris L. 1 YD 752 Tsuga canadensis [planted] (L.) Carriere 1 SR 641

ANTHOPHYTA ACANTHACEAE Ruellia strepens L. 2 F YD 337

164

Abundance & Habitat Collection # ALISMATACEAE Alisma subcordatum Raf. 2 M 413 Sagittaria latifolia Willd. 2 M 506

ALLIACEAE Allium canadense L. ? PP SR YD 228, 391 Allium tricoccum Aiton 3 SR 288, 401 * Allium vineale L. ? PP SR YD 296

ALTINGIACEAE # Liquidambar styraciflua L. 2 SR 376

AMARYLLIDACEAE † Narcissus pseudonarcissus L. 2 YD 37

ANACARDIACEAE Rhus copallina L. 3 F YD 445 Rhus glabra L. 4 F YD 357 Toxicodendron radicans (L.) Kuntze 4 F OW PP SR YD No voucher

ANNONACEAE Asimina triloba (L.) Dunal 4 OW PP SR YD 103, 116

APIACEAE Chaerophyllum procumbens (L.) Crantz 3 PP SR 83, 133

165

Abundance & Habitat Collection # APIACEAE (cont.) Cryptotaenia canadensis (L.) DC. 3 PP SR 234, 329 * Daucus carota L. 4 F YD 429 Erigenia bulbosa (Michx.) Nutt. 2 SR 49, 53 Osmorhiza claytonii (Michx.) C.B. Clarke 4 PP SR YD 148 Osmorhiza longistylis (Torr.) DC. 3 PP SR YD 161, 167 Panax quinquefolius L. 1 PP SR 464 Sanicula canadensis L. 3 PP SR 300, 348 Sanicula gregaria E.P. Bicknell 2 PP SR 205, 699 Sanicula trifoliata E.P. Bicknell 3 PP SR 354 Taenidia integerrima (L.) Drude 1 OW 183 Thaspium barbinode (Michx.) Nutt. 3 SR YD 158 Thaspium trifoliatum (L.) A. Gray 2 OW SR 704 * Torilis japonica (Houtt.) DC. 1 YD 384

APOCYNACEAE Apocynum cannabinum L. 4 F YD 251 Asclepias incarnata L. 2 M 358 Asclepias quadrifolia Jacq. 2 OW 203 Asclepias syriaca L. 3 F YD 316, 468 Asclepias tuberosa L. 4 F YD 304 Cynanchum laeve (Michx.) Pers. 1 F 430 * Vinca minor L. 3 SR YD 85

166

Abundance & Habitat Collection # AQUIFOLIACEAE # Ilex opaca Aiton 1 OW SR 204

ARACEAE Arisaema dracontium (L.) Schott 2 SR 259 Arisaema triphyllum (L.) Schott 3 SR 120, 656

ARISTOLOCHIACEAE Aristolochia serpentaria L. 3 OW SR 606 Asarum canadense L. 4 SR 93, 115

ASTERACEAE Achillea millefolium L. 4 F YD 144 Ageratina altissima (L.) R.M. King & H. Rob. 4 OW PP SR YD 375 Ambrosia artemisiifolia L. 3 YD 476 Ambrosia trifida L. 3 YD 482 Antennaria plantaginifolia (L.) Richardson 3 OW 38 Antennaria solitaria Rydb. 1 OW 35 * Arctium lappa L. 3 YD 614 Arnoglossum atriplicifolium (L.) H. Rob. 2 PO YD 733 Aster cordifolius L. 3 SR YD 7 Aster divaricatus L. 3 F SR YD 10 Aster ericoides L. 3 F YD 570 Aster lanceolatus Willd. ? SR 5 Aster lateriflorus (L.) Britton ? F YD 762

167

Abundance & Habitat Collection # ASTERACEAE (cont.) Aster novae-angliae L. 2 F YD 567 Aster paternus Cronquist 2 OW 730 Aster pilosus Willd. 3 F YD 6 Aster prenanthoides Muhl. ex Willd. 3 SR YD 3, 9 Aster puniceus L. ? SR 602 Aster racemosus Elliot 4 F YD 557 Aster shortii Lindl. ? SR YD 8, 539, 550 Aster undulatus L. ? OW YD 623 Bidens cernua L. 2 M 574 Bidens tripartita L. 3 M SR 543, 571, 590 Bidens vulgata Greene 2 SR 558 * Centaurea dubia Suter 3 YD 537 * Chrysanthemum leucanthemum L. 4 F PP YD 201 * Cichorium intybus L. 4 F YD 390 Cirsium altissimum (L.) Hill 2 F YD 568 * Cirsium arvense (L.) Scop. 4 F YD 305 Cirsium discolor (Muhl. ex Willd.) Spreng. 3 F YD 535 Conyza canadensis (L.) Cronquist 2 F YD 540 * Coreopsis grandiflora R. Hogg ex Sweet 2 F 712 Eclipta prostrata (L.) L. 1 M 759 Elephantopus carolinianus Raeusch. 1 F SR 477 Erechtites hieracifolia (L.) Raf. ex DC. 3 YD 564 Erigeron annuus (L.) Pers 3 F PP YD 230 Erigeron philadelphicus L. 3 F PP YD 150, 163

168

Abundance & Habitat Collection # ASTERACEAE (cont.) Erigeron strigosus Muhl. ex Willd. 3 F PP YD 239, 313 Eupatorium coelestinum L. 3 SR 496 Eupatorium fistulosum Barratt 3 SR 480 Eupatorium perfoliatum L. 2 M YD 485 Eupatorium serotinum Michx. 2 YD 555 Euthamia graminifolia (L.) Nutt. 3 F YD 525 * Galinsoga quadriradiata Ruiz & Pav. 2 YD 381 Gnaphalium obtusifolium L. 1 F YD 1 Gnaphalium purpureum L. 3 F YD 344 * Helenium flexuosum Raf. 2 F YD 347 Helianthus decapetalus L. 3 SR YD 422 Helianthus divaricatus L. 3 SR 419 Helianthus hirsutus Raf. 2 PO YD 741 Helianthus microcephalus Torr. & A. Gray 2 SR YD 750, 751 Helianthus tuberosus L. 2 SR YD 753 Heliopsis helianthoides (L.) Sweet 2 SR YD 495 * Hieracium caespitosum Dumort. 3 F YD 185 Hieracium scabrum Michx. 3 F OW 481, 504 Hieracium venosum L. 3 OW 173 Krigia biflora (Walter) S.F. Blake 2 F PP YD 233 Lactuca canadensis L. 3 SR YD 427 Lactuca floridana (L.) Gaertn. 3 SR YD 489 * Lactuca saligna L. 3 SR YD 441 * Matricaria discoidea DC. 2 YD 713

169

Abundance & Habitat Collection # ASTERACEAE (cont.) Prenanthes altissima L. 3 OW SR YD 552 Ratibida pinnata (Vent.) Barnhart 2 F PO 742 Rudbeckia hirta L. 3 F YD 312 Rudbeckia laciniata L. 2 SR YD 746 Rudbeckia triloba L. 2 F YD 456 Senecio aureus L. 3 SR YD 88 Senecio obovatus Muhl. ex Willd. 3 OW YD 674 Silphium perfoliatum L. 2 SR 424 Silphium trifoliatum L. 3 SR YD 393 Solidago bicolor L. 2 OW 4 Solidago caesia L. 3 SR 583 Solidago canadensis L. 3 F YD 642 Solidago erecta Pursh. 3 F YD 561 Solidago flexicaulis L. 3 SR 601 Solidago gigantea Aiton 3 F YD 553 Solidago juncea Aiton 3 F YD 394 Solidago nemoralis Aiton 2 F YD 458 Solidago speciosa Nutt. 3 F YD 508 Solidago ulmifolia Muhl. ex Willd. 2 F YD 640, 661 * Sonchus asper (L.) Hill 3 YD 462 * Taraxacum officinale Weber ex F.H. Wigg. 4 F L OW PP SR YD 44 * Tragopogon dubius Scop. 2 F YD 208 * Tussilago farfara L. 3 M YD 24, 289 Verbesina alternifolia (L.) Britton ex Kearney 4 F PP SR YD 400

170

Abundance & Habitat Collection # ASTERACEAE (cont.) Vernonia gigantea (Walter) Trel. ex Branner & Coville 3 F SR YD 469 Xanthium strumarium L. 2 YD 544

BALSALMINACEAE Impatiens capensis Meerb. 3 M SR YD 362 Impatiens pallida Nutt. 3 M SR YD 326

BERBERIDACEAE * Berberis thunbergii DC. 3 OW PP SR 72 Caulophyllum thalictroides (L.) Michx. 3 SR 33 Jeffersonia diphylla (L.) Pers. 3 SR YD 30 Podophyllum peltatum L. 4 OW PP SR 145, 206

BETULACEAE Betula nigra L. 1 M 692 Carpinus caroliniana Walter 4 OW PP SR YD 556 Corylus americana Walter 3 SR YD 16, 548 Ostrya virginiana (Mill.) K. Koch 4 OW PP SR YD 621

BIGNONIACEAE Campsis radicans (L.) Seem. ex Bureau 3 F YD 345

BORAGINACEAE Cynoglossum virginianum L. 3 OW PP 184

171

Abundance & Habitat Collection # BORAGINACEAE (cont.) Hackelia virginiana (L.) I.M. Johnst. 3 PP SR YD 379 Hydrophyllum appendiculatum Michx. 2 SR 164 Hydrophyllum canadense L. 3 SR 279 Hydrophyllum macrophyllum Nutt. 3 SR 216, 226 Lithospermum canescens (Michx.) Lehm. 2 PO 191 Lithospermum latifolium Michx. 2 PP SR YD 209 Mertensia virginica (L.) Pers. ex Link 2 SR 31 * Myosotis arvense (L.) Hill 3 OW YD 109 Myosotis macrosperma Engelm. 3 SR 162 * Myosotis scorpioides L. 3 M 180 Phacelia purshii Buckley 1 SR 206

BRASSICACEAE * Alliaria petiolata (M. Bieb.) Cavara & Grande 3 PP YD 112 Arabis canadensis L. 2 OW SR 351 PT Arabis hirsuta (L.) Scop. var. adpressipilis (M. Hopkins) Rollins 1 OW 171

Arabis laevigata (Muhl. ex Willd.) Poir. 3 OW SR 63, 267 * Barbarea vulgaris R. Br. 4 F YD 66, 172 Cardamine concatenata (Michx.) Sw. 4 OW PP SR YD 21, 129 Cardamine diphylla (Michx.) A.W. Wood 3 SR 97 Cardamine douglasii Britton 4 OW PP SR YD 20 * Cardamine hirsuta L. 4 L PP SR YD 13 Cardamine pennsylvanica Muhl. 3 PP SR YD 136, 138 Cardamine rotundifolia Michx. 1 M 146

172

Abundance & Habitat Collection # BRASSICACEAE (cont.) * Erophila verna (L.) Besser 3 F L YD 52 * Erucastrum gallicum (Willd.) O.E. Schultz 1 SR 222 * Hesperis matronalis L. 1 YD 181 Iodanthus pinnatifidus (Michx.) Steud. 2 SR 165, 212 * Lepidium campestre (L.) R Br. 3 F PO YD 188

CAMPANULACEAE Campanula americana L. 4 PP SR YD 365 Lobelia inflata L. 4 OW PP SR YD 385 Lobelia siphilitica L. 3 SR YD 501 Lobelia spicata Lam. 1 F YD 287

CAPRIFOLIACEAE * Dipsacus fullonum L. 3 F YD 536 * Lonicera japonica Thunb. 4 F OW PP SR YD 231 * Lonicera maackii (Rupr.) Maxim. 3 F OW SR YD 105 * Lonicera morrowi A. Gray 2 SR YD 651 Sambucus canadensis L. 3 M SR YD 310 Symphoricarpos orbiculatus Moench 1 YD 745 Triosteum angustifolium L. 2 OW SR 453 Valerianella chenopodifolia (Pursh) DC. 4 SR YD 182, 224 Valerianella umbilicata (Sull.) A.W. Wood ? SR 155 Viburnum acerifolium L. 3 OW 170 Viburnum prunifolium L. 4 F YD 75, 576

173

Abundance & Habitat Collection #

CARYOPHYLLACEAE * Cerastium fontanum Baumg. 4 F L PP SR YD 194 * Dianthus armeria L. 3 F YD 213 * Myosoton aquaticum (L.) Moench 2 SR YD 361 Paronychia canadensis (L.) A.W. Wood 2 OW SR 322 * Silene latifolia Poir. 1 YD 734 Silene stellata (L.) W.T. Aiton 2 OW 340 Silene virginica L. 3 OW 113 Stellaria longifolia Muhl. ex. Willd. 2 SR 237 * Stellaria media (L.) Vill. 4 F L OW PP SR YD 27, 134 Stellaria pubera Michx. 3 OW YD 368

CELASTRACEAE * Celastrus orbiculatus Thunb. 4 F PP YD 149 Celastrus scandens L. 2 F YD 615 * Euonymus alatus (Thunb.) Siebold 3 F PP YD 107 Euonymus atropurpureus Jacq. 2 PP YD 603 * Euonymus fortunei (Turcz.) Hand.-Mazz. 1 SR 582

CELTIDACEAE Celtis occidentalis L. 3 OW SR YD 563

174

Abundance & Habitat Collection # CLUSIACEAE Hypericum mutilum L. 3 M 433 Hypericum punctatum Lam. 3 F YD 343, 448

COMMELINACEAE * Commelina communis L. 2 OW YD 380 Tradescantia virginiana L. 2 OW YD 169

CONVALLARIACEAE Polygonatum biflorum (Walter) Elliott 2 OW SR 693 Polygonatum pubescens (Willd.) Pursh 3 PO SR 151 Smilacina racemosa (L.) Desf. 3 OW SR 193, 261

CONVOLVULACEAE Calystegia sepium (L.) R. Br. 3 F YD 426 Cuscuta gronovii Willd. ex Scholt. 2 SR YD 542 Ipomoea pandurata (L.) G. Mey. 3 F YD 392

CORNACEAE Cornus alternifolia L. f. 2 YD 242 Cornus florida L. 4 F OW SR YD 74 Cornus racemosa Lam. 1 YD 764 Nyssa sylvatica Marshall 3 OW SR 580

175

Abundance & Habitat Collection # CRASSULACEAE Sedum ternatum Michx. 4 OW SR 119, 137

CYPERACEAE Carex albicans Willd. ex Spreng. 2 OW YD 672 Carex albursina E. Sheld. 3 SR 673, 677 Carex amphibola Steud. 3 M 703 Carex frankii Kunth 3 M 388 Carex glaucodea Tuck ex Olney ? OW SR 706 Carex granularis Muhl. ex Willd. 3 SR YD 333 Carex grayii Carey 2 M 749 Carex hirsutella Mack. 2 F YD 709 Carex hitchcockiana Dewey 2 OW 685 Carex laxiculmis Schwein. 2 OW SR 268 Carex laxiflora Lam. 2 OW SR 689 Carex lupulina Muhl. ex Willd. 3 M 719 Carex lurida Wahlenb. 2 M 307, 474 Carex normalis Mack. 3 M 696 Carex pensylvanica Lam. ? OW YD 686 Carex platyphylla J. Carey ? SR 681 Carex rosea Schkuhr ex Willd. 3 OW SR 682 Carex shortiana Dewey 3 M 694, 705 Carex tetanica Schkuhr 1 PO 688 Carex torta Boott ex Tuck. 1 SR 691 Carex vulpinoidea Michx. 3 M 695, 697

176

Abundance & Habitat Collection # CYPERACEAE (cont.) Cyperus echinatus (L.) A.W. Wood 3 M 397 Cyperus flavescens L. 3 M 494 Cyperus strigosus L. 3 M 411, 436, 437 Eleocharis ovata (Roth) Roem. & Schult. 2 M YD 454 Scirpus atrovirens Willd. 3 M 275, 281 Scirpus polyphyllus Vahl. 3 M 274

DIOSCOREACEAE Dioscorea villosa L. 3 SR YD 364

EBENACEAE Diospyros virginiana L. 3 F PO YD 593

ELAEAGNACEAE * Elaeagnus umbellata Thunb. 3 F YD 104, 549

ERICACEAE Chimaphila maculata (L.) Pursh 2 OW PP 41, 341 Gaylussacia baccata (Wangehn.) Koch 2 OW 598, 618 Kalmia latifolia L. 2 OW 210 Monotropa uniflora L. 2 OW SR 356 Oxydendrum arboreum (L.) DC. 3 OW 572 Pyrola sp. 1 OW 92 Vaccinium pallidum Aiton 3 OW 77

177

Abundance & Habitat Collection # ERICACEAE (cont.) Vaccinium stamineum L. 3 OW YD 143

EUPHORBIACEAE † Acalypha gracilens A. Gray ? PP SR YD 215 Acalypha virginica L. var. virginica L. ? PP SR YD 378 Acalypha virginica L. var. rhomboidea (Raf.) Cooperr. 3 PP SR YD 467 Euphorbia corollata L. 3 F YD 290 Euphorbia maculata L. 2 L YD 440 Euphorbia nutans Lag. 2 L YD 538 Euphorbia obtusata Pursh 2 SR YD 197

FABACEAE Amphicarpaea bracteata (L.) Fernald 4 PP SR YD 503 Apios americana Medik. 3 F YD 386 Cercis canadensis L. 4 OW PO PP SR YD 46 Chamaecrista nictitans (L.) Moench 3 F YD 447 * Coronilla varia L. 2 YD 455 Desmodium canescens (L.) DC. 2 F YD 389 Desmodium nudiflorum (L.) DC. 3 F PP YD 449 Desmodium paniculatum (L.) DC. 3 F YD 423, 499 Desmodium rigidum (Elliot) DC. 3 F YD 484 Desmodium rotundifolium DC. 2 OW PP YD 517 Gleditsia triacanthos L. 3 SR 591 Gymnocladus dioica (L.) K. Koch 1 SR 633 * Kummerowia striata (Thunb.) Schindl. 3 F YD 509

178

Abundance & Habitat Collection # FABACEAE (cont.) * Lespedeza cuneata (Dumont) G. Don 2 F YD 511 Lespedeza hirta (L.) Hornem. 3 F YD 488 Lespedeza intermedia (S. Watson) Britton 3 F YD 510 Lespedeza procumbens Michx. 3 F YD 531 Lespedeza repens (L.) Barton 2 F YD 498, 516 Lespedeza violacea (L.) Pers. 2 F YD 566 Lespedeza virginica (L.) Britton 3 F YD 502, 562 * Lotus corniculatus L. 2 L 382 * Medicago lupulina L. 3 F YD 178 * Melilotus albus Medik. 3 F YD 293 * Melilotus officinalis (L.) Pall. 4 F PO YD 199 Robinia pseudoacacia L. 4 F SR YD 644 Senna hebecarpa (Fernald) Irwin & Barneby 1 YD 446 Strophostyles helvula (L.) Elliot 1 F 512 * Trifolium aureum Pollich 3 F YD 352 * Trifolium campestre Schreb. 3 F YD 252 * Trifolium hybridum L. 3 F YD 280 * Trifolium pratense L. 4 F YD 202 * Trifolium repens L. 4 F L YD 177 * Vicia dasycarpa Ten. 3 F YD 198 * Vicia villosa Roth 2 YD 732 † Wisteria sp. 1 YD 679

179

Abundance & Habitat Collection # FAGACEAE Castanea dentata (Marsh.) Borkh. 1 OW 594 Fagus grandifolia Ehrh. 4 OW SR 573 Quercus alba L. 4 OW SR 625 Quercus coccinea Munchh. 2 OW 652 Quercus muehlenbergii Engelm. 2 OW SR YD 622 Quercus prinus L. 4 OW 585 Quercus rubra L. 4 OW SR 631 Quercus stellata Wangenh. 1 OW 626 Quercus velutina Lam. 4 OW SR 599, 617

GENTIANACEAE Obolaria virginica L. 1 SR 108 Sabatia angularis (L.) Pursh 2 F YD 416 Swertia caroliniensis (Walter) Kuntze 2 OW PO No voucher

GERANIACEAE Geranium carolinianum L. 2 F YD 196 Geranium maculatum L. 3 SR 79, 122

HAMAMELIDACEAE Hamamelis virginiana L. 2 OW SR 629

HEMEROCALLIDACEAE * Hemerocallis fulva (L.) L. 3 SR YD 328

180

Abundance & Habitat Collection #

HYDRANGEACEAE Hydrangea arborescens L. 3 SR 309 † Hydrangea sp. 1 YD 739 † Philadelphus sp. 1 SR YD 678

HYPOXIDACEAE Hypoxis hirsuta (L.) Coville 2 OW 690

IRIDACEAE * Iris pseudacorus L. 2 M 238 Sisyrinchium angustifolium Mill. 3 F YD 187

JUGLANDACEAE Carya cordiformis (Wangenh.) K. Koch 3 SR YD 589 Carya glabra (Mill.) Sweet 4 OW SR 616 Carya laciniosa (F. Michx.) Loudon 2 SR 654 Carya ovata (Mill.) K. Koch 3 OW SR 628, 639 Carya tomentosa (Poir.) Nutt. 3 OW 763 Juglans nigra L. 4 SR YD 578

JUNCACEAE Juncus acuminatus Michx. 3 M YD 438 Juncus effusus L. 2 M YD 271 Juncus marginatus Rostk. 2 M 428

181

Abundance & Habitat Collection # JUNCACEAE (cont.) Juncus tenuis Willd. 3 M 406 Luzula echinata (Small) F.J. Herm. 2 OW PP 675 Luzula multiflora (Retz.) Lej. 3 OW PP 61, 160

LAMIACEAE Blephilia ciliata (L.) Benth. 1 PO 277 Blephilia hirsuta (Pursh) Benth. 2 SR 349 Clinopodium vulgare L. 2 YD 431 Collinsonia canadensis L. 2 SR YD 483 Cunila origanoides (L.) Britton 3 OW 518 * Glechoma hederacea L. 4 F L PP SR YD 43 Hedeoma pulegioides (L.) Pers. 2 F OW 466, 744 * Lamium purpureum L. 4 F L PP SR YD 45, 130 * Leonurus cardiaca L. 2 YD 600 Lycopus americanus Muhl. ex W.P.C. Barton 3 M SR 408 Lycopus virginicus L. 3 M SR 463, 473 * Mentha x piperita L. 3 M 443 Monarda fistulosa L. var. fistulosa L. 3 F PO SR YD 370 Monarda fistulosa L. var. clinopodia (L.) Cooperr. 2 SR 736 Physostegia virginiana (L.) Benth ssp. praemorsa (Shinners) P.D. Cantino 1 PO 565 Prunella vulgaris L. 4 F L SR YD 359 Pycanthemum pycanthemoides (Leavenw.) Fernald 1 OW 452 Pycanthemum tenuifolium Schrad. 3 F YD 346 Scutellaria incana Biehler 2 SR YD 412, 418

182

Abundance & Habitat Collection # LAMIACEAE (cont.) Scutellaria lateriflora L. 3 M SR 417 Scutellaria nervosa Pursh 2 OW 702 Scutellaria ovata Hill 2 OW SR 355 Scutellaria serrata Andrews 2 SR 232 Stachys nuttalli Shuttlew ex Benth. 2 SR 306, 731 Teucrium canadense L. 2 SR YD 450

LAURACEAE Lindera benzoin (L.) Blume 4 SR YD 22 Sassafras albidum (Nutt.) Nees 4 OW YD 611

LILIACEAE Erythronium albidum Nutt. 2 YD 19 Erythronium americanum Ker Gawl. 3 SR 55 Lillium canadense L. 1 SR 366 Medeola virginiana L. 1 SR 374 * Ornithogalum umbellatum L. 2 SR YD 700

LIMNANTHACEAE Floerkea proserpinacoides Willd. 3 SR 95

LINACEAE Linum virginianum L. 2 F YD 338

183

Abundance & Habitat Collection # LYTHRACEAE Cuphea viscosissima Jacq. 2 F 755

MAGNOLIACEAE Liriodendron tulipifera L. 4 SR YD 157 Magnolia acuminata (L.) L. 1 SR 735

MALVACEAE Hibiscus moscheutos L. 3 M 435 Tilia americana L. 3 SR YD 586

MENISPERMACEAE Menispermum canadense L. 3 SR YD 638, 716

MORACEAE * Maclura pomifera (Raf.) C. K. Schneid. 2 YD 592 Morus rubra L. 2 SR YD 575

OLEACEAE † Forsythia viridissima Lindl. 1 SR 670 Fraxinus americana L. var. americana L. 2 SR 645 Fraxinus americana L. var. biltmoreana (Beadle) J. Wright ex Fernald 2 SR YD 596, 624 Fraxinus pennsylvanica Marshall 4 SR YD 650 Fraxinus quadrangulata Michx. 1 SR 680 * Ligustrum vulgare L. 4 OW PP SR YD 218, 219

184

Abundance & Habitat Collection # ONAGRACEAE Circaea lutetiana L. 4 PP SR YD 308 Epilobium coloratum Biehler 3 M 526 Ludwigia alternifolia L. 3 M YD 396 Ludwigia palustris (L.) Elliott 2 M 760 Oenothera biennis L. 3 F YD 478

ORCHIDACEAE Aplectrum hyemale (Muhl. ex Willd.) Torr 2 OW PP 663, 701 Corallorhiza odontorhiza (Willd.) Poir. 3 OW PP 519 PT Corallorhiza wisteriana Conrad 1 OW 189 Galearis spectabilis (L.) Raf. 2 SR 152 Goodyera pubescens (Willd.) R. Br. ex W.T. Aiton 3 OW PP 398 Liparis liliifolia (L.) Rich. ex Lind. 2 OW PP 314 Platanthera lacera (Michx.) G. Don 2 M 415, 721 Spiranthes lacera (Raf.) Raf. 2 F 500 PT Spiranthes ovalis Lindl. 1 YD 613 Spiranthes vernalis Engelm. & A. Gray 2 F 479 Tipularia discolor (Pursh) Nutt. 2 OW 662, 740

OROBANCHACEAE Aureolaria laevigata (Raf.) Raf. 2 OW 597 Aureolaria virginica (L.) Pennell 2 OW YD 395 Conopholis americana (L.) Wallr. 3 OW 192, 266 Epifagus virginiana (L.) Barton 4 OW SR 541 Orobanche uniflora L. 1 SR YD 159

185

Abundance & Habitat Collection #

OXALIDACEAE Oxalis dillenii Jacq. 3 OW PP SR 174, 524 Oxalis grandis Small 2 OW YD 258 Oxalis stricta L. 3 L OW PP SR YD 227 Oxalis violacea L. 3 OW SR 99, 168

PAPAVERACEAE Corydalis flavula (Raf.) DC. 2 SR 28 Dicentra canadensis (Goldie) Walp. 2 SR 36 Dicentra cucullaria (L.) Bernh. 3 SR 32 Sanguinaria canadensis L. 3 SR 29, 128

PHRYMACEAE Mimulus alatus Aiton 2 M 369 Mimulus ringens L. 2 M 442 Phryma leptostachya L. 3 PP SR 353

PHYTOLACCACEAE Phytolacca americana L. 3 F YD 332

PLANTAGINACEAE Chelone glabra L. 1 SR 559 Collinsea verna Nutt. 3 SR 655

186

Abundance & Habitat Collection # PLANTAGINACEAE (cont.) Lindernia dubia (L.) Pennell 1 YD 722 Penstemon digitalis Nutt. ex Sims 3 F SR YD 217 * Plantago lanceolata L. 4 F L YD 200 Plantago rugelii Decne. 3 F L YD 372 * Veronica arvensis L. 3 F L YD 207 * Veronica officinalis L. 3 F L YD 195 * Veronica polita Fr. 3 F L YD 14 * Veronica serpyllifolia L. 3 F L YD 291, 660 Veronicastrum virginicum (L.) Farw. 2 SR YD 451

PLATANACEAE Platanus occidentalis L. 4 SR 643

POACEAE * Agrostis gigantea Roth ? SR YD 497, 723 Agrostis perennans (Walter) Tuck. ? OW YD 490 Andropogon gerardii Vitman 1 PO 2 † Anthoxanthum odoratum Boiss. 2 YD 684 Aristida oligantha Michx. 2 F 514 * Bromus commutatus Schrad. 3 F PO YD 324 Bromus pubescens Muhl. ex Willd. 3 SR YD 421, 717 * Bromus racemosus L. 3 F YD 270 * Dactylis glomerata L. 3 F L YD 707 Danthonia spicata (L.) P. Beauv. ex Roem. & Schult. 3 YD F L 710

187

Abundance & Habitat Collection # POACEAE (cont.) * Digitaria ischaemum (Schreb.) Muhl. 3 L YD 530 Echinochloa muricata (P. Beauv.) Fernald. 2 F YD 460, 507 Elymus hystrix L. 4 F SR YD 299 Elymus riparius Wiegand ? F SR YD 457 Elymus trachycaulus (Link) Gould ex. Shinners ? F SR YD 724 Elymus villosus Muhl. ex Willd. ? F SR YD 472 Elymus virginicus L. ? F SR YD 360 Eragrostis capillaris (L.) Nees 2 F YD 754 Eragrostis spectabilis (Pursh) Steud. 2 F YD 475, 551 Festuca subverticillata (Pers.) E.B. Alexeev 3 F L YD 444, 715 Glyceria melicaria (Michx.) F.T. Hubb. 3 PP SR YD 714 Glyceria striata (Lam.) Hitchc. 3 SR 292, 718 * Holcus lanatus L. ? F L YD 403 Leersia virginica Willd. 2 M YD 529 * Lolium perenne L. ? F L YD 711 * Lolium pratense (Huds.) Darbysh. ? F L YD 273 * Microstegium vimineum (Trin.) A. Camus 2 SR YD 761 * Miscanthus sinensis Andersson 1 F 581 Muhlenbergia frondosa (Poir) Fernald 3 F YD 505 Panicum acuminatum Sw. ? PP SR YD 276, 383, 748 Panicum boscii Poir. ? OW SR 493 Panicum clandestinum L. ? SR YD 295 Panicum linearifolium Scribn. ex Nash ? SR YD 272 Paspalum pubiflorum Rupr. ex E. Fourn. ? F YD 491 Paspalum setaceum Michx. ? F L YD 439, 515

188

Abundance & Habitat Collection # POACEAE (cont.) Phalaris arundinacea L. 3 M YD 708 * Phleum pratense L. 2 F YD 303 * Poa compressa L. 3 L OW PP SR YD 269 Poa cuspidata Nutt. 3 L OW PP SR YD 17, 676 Schizachyrium scoparium (Michx.) Nash 4 F PO YD 513 * Setaria glauca (L.) P. Beauv. 3 F YD 492, 747 * Sorghum halepense (L.) Pers. 2 YD 402 Tridens flavus (L.) Hitchc. 2 F YD 470

POLEMONIACEAE Phlox divaricata L. 3 OW SR 59, 125 Phlox paniculata L. 3 SR YD 367 Polemonium reptans L. 3 SR 82

POLYGALACEAE Polygala sanguinea L. 1 F 726 Polygala verticillata L. 2 F YD 350

POLYGONACEAE * Polygonum arenastrum Jord. ex Boreau 3 YD 404 * Polygonum cespitosum Blume 4 F SR YD 335 * Polygonum convolvulus L. 3 YD 520, 569 * Polygonum cuspidatum Siebold & Zucc. 2 YD 327 Polygonum punctatum Elliot 3 SR YD 471

189

Abundance & Habitat Collection # POLYGONACEAE (cont.) Polygonum sagittatum L. 3 M 318 Polygonum virginianum L. 4 SR YD 371 * Rumex acetosella L. 3 F YD 176, 342 * Rumex crispus L. 3 PP YD 211 * Rumex obtusifolius L. 3 PP YD 334

PORTULACACEAE Claytonia virginica L. 4 OW SR YD 25, 135 * Portulaca oleracea L. 3 F YD 659

PRIMULACEAE Lysimachia ciliata L. 3 F YD 317 * Lysimachia nummularia L. 3 L M 235 Lysimachia quadrifolia L. 3 OW PP YD 301 Samolus parviflorus Raf. 1 M YD 387

RANUNCULACEAE Actaea pachypoda Elliot 2 SR 377 Anemone virginiana L. 3 PP SR 321 Aquilegia canadensis L. 1 R 78 Cimicifuga racemosa (L.) Nutt. 3 SR 339 Clematis viorna L. 1 F 330 Clematis virginiana L. 3 F YD 459 Delphinium tricorne Michx. 2 SR 117

190

Abundance & Habitat Collection # RANUNCULACEAE (cont.) Hepatica acutiloba DC. 3 OW SR 26, 50 Hydrastis canadensis L. 2 SR 90 Ranunculus abortivus L. 4 OW PP SR YD 68, 84 Ranunculus allegheniensis Britton 2 OW 687 Ranunculus hispidus Michx. 3 OW PP SR YD 141, 156 Ranunculus micranthus Nutt. 3 OW PP SR YD 57, 67, 123 Ranunculus recurvatus Poir. 3 OW PP SR YD 114, 147 Thalictrum dioicum L. 3 OW 102 Thalictrum thalictroides (L.) A.J. Eames & B. Boivin 3 OW 23

RHAMNACEAE Ceanothus americanus L. 1 OW 737

ROSACEAE Agrimonia gryposepala Wallr. 3 M SR 420 Agrimonia parviflora Aiton 3 PP SR 432 Agrimonia pubescens Wallr. 3 PP SR 373 Amelanchier arborea (F. Michx.) Fernald 2 OW 47 Crataegus spp. 3 F OW YD 140, 588 * Duchesnea indica (Andrews) Focke 4 F L PP YD 131, 229, 657 Fragaria virginiana Duchesne 3 F YD 73 Geum canadense Jacq. 3 PP SR 325 Geum laciniatum Murray 2 PP SR 434 Geum vernum (Raf.) Torr. & A. Gray 3 OW PP SR YD 87, 132

191

Abundance & Habitat Collection # ROSACEAE (cont.) Malus angustifolia (Aiton) Michx. 2 F YD 106 Malus coronaria (L.) Mill. 2 F YD 70, 587 Porteranthus stipulatus (Muhl. ex Willd.) Britton 3 OW 323 Potentilla canadensis L. 3 F OW YD 100 * Potentilla recta L. 3 F YD 283 Potentilla simplex Michx. 3 F OW SR YD 71 Prunus americana Marshall 1 YD 76 Prunus serotina Ehrh. 4 OW PP SR YD 154, 619 † Pyrus communis L. 2 YD 48 * Rosa canina L. 2 F YD 311 Rosa carolina L. 3 F OW 214 * Rosa multiflora Thunb. ex Murray 4 F OW PP SR YD 166 Rosa setigera Michx. 1 F 315 Rubus allegheniensis Porter 3 OW PP SR YD 425 Rubus flagellaris Willd. 4 OW PP SR YD 142 Rubus occidentalis L. 4 OW PP SR YD 179 Rubus pensilvanicus Poir. 4 OW PP SR YD 175 * Rubus phoenicolasius Maxim. 2 PP SR YD 363

RUBIACEAE Cephalanthus occidentalis L. 1 M 410 Galium aparine L. 4 OW PP SR YD 64, 65, 124 Galium circaezans Michx. 4 OW PP SR YD 265, 282 Galium concinnum Torr. & A. Gray 3 OW PP SR 297 Galium lanceolatum Torr. 2 OW SR 236

192

Abundance & Habitat Collection # RUBIACEAE (cont.) Galium tinctorium (L.) Scop. 2 M 527 Galium triflorum Michx. 3 OW PP SR YD 727 Houstonia caerulea L. 3 F OW YD 139 Houstonia longifolia Gaertn. 2 F OW YD 286 Mitchella repens L. 2 PP R SR 278

SALICACEAE Populus deltoides W. Bartram ex Marshall 2 SR No voucher Populus grandidentata Michx 3 OW YD 632 † Populus x jackii Sarg. 1 SR 667 * Salix fragilis L. 2 F M 758 Salix interior Rowlee 3 M 743 Salix nigra Marshall 3 M 683

SAPINDACEAE Acer negundo L. 3 SR YD 658 Acer rubrum L. 4 OW PP SR YD 627 Acer saccharinum L. 3 YD 637 Acer saccharum Marshall 4 OW SR YD 612 Aesculus flava Aiton 4 PP SR YD 110

SAXIFRAGACEAE Heuchera americana L. 3 OW 190 Mitella diphylla L. 2 SR 54

193

Abundance & Habitat Collection # SAXIFRAGACEAE (cont.) Penthorum sedoides L. 3 M 409 Saxifraga virginiensis Michx. 3 OW 42, 60, 126 Tiarella cordifolia L. 2 SR 96

SCROPHULARIACEAE * Verbascum blattaria L. 2 F YD 284 * Verbascum thapsus L. 3 F YD 320

SIMAROUBACEAE * Ailanthus altissima (Mill.) Swingle 2 YD 584

SMILACEAE Smilax glauca Walter 3 OW 630 Smilax hispida Muhl. ex Torr. 3 SR YD 620 Smilax rotundifolia L. 4 OW PP SR YD 186

SOLANACEAE Physalis heterophylla Nees 3 F YD 240 Physalis longifolia Nutt. 3 YD 487 Solanum carolinense L. 3 F YD 298 Solanum nigrum L. 2 YD 465

STAPHYLEACEAE Staphylea trifolia L. 2 SR 111, 554

194

Abundance & Habitat Collection #

THYMELAEACEAE Dirca palustris L. 2 SR 664, 669

TRILLIACEAE Trillium erectum L. 1 SR 671 Trillium flexipes Raf. 1 SR No voucher Trillium grandiflorum (Michx.) Salisb. 4 SR 56, 262 Trillium sessile L. 1 SR 34, 86

TYPHACEAE * Typha angustifolia L. 2 M 319 Typha latifolia L. 3 M 738

ULMACEAE Ulmus americana L. 4 OW SR YD 579 Ulmus rubra Muhl. 3 SR YD 648

URTICACEAE Boehmeria cylindrica (L.) Sw. 4 M 399 Laportea canadensis (L.) Wedd. 4 SR 414 Pilea pumila (L.) A. Gray 4 SR YD 461

UVULARIACEAE Uvularia grandiflora Sm. 2 SR 101

195

Abundance & Habitat Collection #

VERBENACEAE Verbena urticifolia L. 3 SR YD 331

VIOLACEAE Viola canadensis L. 3 SR 94, 121 Viola palmata L. 3 OW SR 80 Viola pubescens Aiton 3 OW PP SR YD 40, 58, 127 Viola rostrata Pursh 1 SR 62 Viola sororia Willd. 4 L PP SR YD 39, 51 Viola striata Aiton 3 SR 81

VITACEAE Parthenocissus quinquefolia L. 4 F OWPO SRYD 756 Vitis aestivalis Michx. 2 OW 757 Vitis riparia Michx. 3 SR YD 285 Vitis vulpina L. 4 SR YD 577