ABSTRACT
WALKER, ANDREW SCOTT. Soil Seedbank of Rare Plant Communities Associated with Diabase Soils in Durham and Granville Counties, North Carolina. (Under the direction of Dr. Jon M. Stucky)
In Northeastern Durham County and Southwestern Granville County, North Carolina, there are a cluster of unique, species-rich plant communities associated with diabase soils. These communities are characterized by an abundance of shade-intolerant forbs with prairie affinities, including the federally endangered smooth coneflower, Echinacea laevigata.
Monitoring reports of E. laevigata indicate that, while most populations declined between
1988 and 2002, the population at Picture Creek Diabase Barren increased dramatically, presumably in response to a prescribed fire and canopy clearing associated with a power line right of way. This suggested the possibility that E. laevigata and other rare plants form a persistent soil seed bank which can contribute to population increases. Presence of a soil seed bank could have conservation value and facilitate restoration of other “prairie remnants” in the area. We tested the soil seed bank at Picture Creek and two other nearby locations which have similar floras and were reported to have had similar numbers of E. laevigata in
1988. We also tested the litter layer at Picture Creek. No rare plants were found in the soil seed bank, but a few were recovered from the leaf litter.
Soil Seedbank of Rare Plant Communities Associated with Diabase Soils in Durham and Granville Counties, North Carolina
by Andrew S. Walker
A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the degree of Master of Science
Botany
Raleigh, North Carolina
2009
APPROVED BY:
______Dr. James Mickle Dr. Robert Beckmann
______Dr. Jon Stucky Committee Chair . ii
DEDICATION
To my father, Gabriel Walker Jr.
iii
BIOGRAPHY
Andrew Walker was born and raised in Portland, Maine. He earned a degree in English from the University of Chicago, after which spent the next decade in Seattle and Chicago working at a variety of jobs. During this time, he developed a strong interest in botany, which led him to graduate school at NCSU. Andrew now works in the conservation department at the North
Carolina Botanical Garden.
iv
ACKNOWLEDGMENTS
It was a great pleasure working with Dr. John Stucky, and I thank him for his patience and support. Special thanks are due to Sue Vitello, whose encouragement has meant a great deal to me. I am also grateful for my fellow students and good friends Laura Gadd and Wade
Wall. Without their help I couldn’t have completed this project v
TABLE OF CONTENTS
LIST OF TABLES ...... vi
LIST OF FIGURES ...... vii
1 Introduction ...... 1
2 Methods ...... 5
3 Results ...... 9
4 Discussion ...... 10
Bibliography ...... 13
APPENDICES ...... 16
Appendix A: Rare plants found on study sites ...... 17
Appendix B: Soil seed bank results ...... 19
Appendix C: Litter layer results ...... 21
vi
LIST OF TABLES
Table 1 Echinacea laevigata population changes at study sites ...... 5 vii
LIST OF FIGURES
Figure 1 Smooth coneflower in the power line right-of-way ...... 2
at Picture Creek Diabase Barrens
Figure 2 Woody encroachment at Picture Creek between 1955 and 2003 ...... 4
1
Introduction
In Durham and Granville counties, North Carolina, a locally unique plant community is found on diabase soils belonging to the Iredell and Picture Soil Series. These sites contain some of the highest concentrations of rare plants in the North Carolina piedmont (Oakley et al 1995). The community type has been described as a Xeric Hardpan Forest Community
(Prairie Barren Subtype) (Schafale 2004), and is characterized by the presence of many shade-intolerant species with prairie affinities. Some consider these remnant “Piedmont
Prairies” (Barden2002), which were historically more extensive. All of these areas have been altered from their natural state by logging, fire suppression and other disturbances.
Today the prairie forbs are generally restricted to artificial clearings along roadsides, railroad tracks, and in power line rights-of-way (ROWs).
One of the best remaining examples of this community is Picture Creek Diabase
Barrens in Butner, NC, which has the largest known population of the federally endangered smooth coneflower, Echinacea laevigata (C.L. Boynton & Beadle) S.F. Blake (Figure 1). In addition to the smooth coneflower, at least 16 other species (Appendix A) recognized as rare are found at this site (1994 NC NHP site report). The vast majority of the rare plants occur in a large (60 meter wide) power line ROW, and in an area of open woodland which experienced a prescribed burn in April 1994 (Murdock 1995). The remainder of this site has a fairly closed canopy. Aerial photographs taken in 1955, 1972, and 1997 clearly demonstrate an increase in forest cover during this time (Figure 2).
The power line ROW at Picture Creek Diabase Barrens was installed in the mid
1980’s (Barnett-Lawrence 1993). A 1988 survey of the smooth coneflower at this site 2
estimated that there were a total of 200 flowering stems and 2000 rosettes (Gaddy 1991). In
2001 the population of smooth coneflower in the power line ROW was estimated at over
10,000 flowering stems and over 100,000 rosettes (Lundsford 2002). In the nearby woodland opening, which was burned in 1994, a single 1000 m2 vegetation plot sampled in 2001 tallied nearly 9000 rosettes and 1009 flowering stems (Lundsford 2002).
Figure 1: Smooth coneflower in the power line right-of-way at Picture Creek Diabase
Barrens. Picture taken June 2006. 3
Although not documented, we assume that some of the other rare species which today thrive alongside Echinacea laevigata at Picture Creek Diabase Barrens also increased as a result of the prescribed burn and the canopy opening associated with the power line ROW installation. The dramatic increase in the number of smooth coneflower plants suggested that there may have been some recruitment from a persistent soil seed bank. Confirming that smooth coneflower and possibly other rare forbs persist in the seed bank could have important restoration potential. “Prairie remnants”, already few in number and isolated from each other, persist mainly along roadsides where they are vulnerable to herbicide spraying, untimely mowing, and destruction caused by road widening and development. Recruitment from a soil seed bank could help restore and expand these species-rich plant communities.
Also, research on smooth coneflower has shown that there is genetic variability between geographically close populations (Peters 2004), and recruitment of new individuals in situ from a soil seed bank would be an excellent and an inexpensive way to retain the genetics of small, isolated plant populations. Our objectives in this seed bank study were to ascertain if smooth coneflower and other rare prairie forbs form a persistent soil seed bank.
Previous studies of prairie communities have found that the seed bank was dominated by ruderal species and was not strongly correlated with the above-ground vegetation
(Johnson 1986, Rabinowitz 1981, Abrams 1996, Laughlin 2003). However, the communities tested in those studies were dominated by grasses and had a relatively low density of prairie forbs. In comparison, the communities included in this study are dense with perennial forbs.
Some of our target species (Ruellia humulis(Nuttall), Symphyotrichum leave (Linnaeus), and congeners of others (Echinacea pallid(Nuttall), Silphium spp., Parthenium integrifolium 4
(Linnaeus)) were recovered in small numbers from the seed bank of a tallgrass prairie in
Illinois (Johnson 1986). Given the density of prairie forbs at Picture Creek Diabase Barrens, this offered some encouragement that some of the state listed prairie forbs listed in Appendix
A, including smooth coneflower, may be present in the soil seed bank at these remnant sites.
Woody encroachment at Picture Creek between 1955 and 2003
Figure 2: 1955 aerial is on the left, 2003 on the right. Circles indicate areas where rare plants are found today. Diagonal lines drawn on 1955 photo approximate location of the power line ROW established in mid 1980's. The north-south road which bisects the circle in the 1955 photo still exists, but is overgrown and no longer visible in the 2003 photo.
5
Methods
Site selection
According to the 1990 monitoring report, the Picture Creek Diabase Barren, Eno
River Diabase Sill (ERDS), and the Knap of Reeds Diabase Levee and Slopes(KORLS) natural areas had comparable populations of smooth coneflower (Table 1). In addition to the smooth coneflower, many other rare plants occur at these sites (Appendix A). At the time of this study, the smooth coneflower populations at Eno River Diabase Sill and Knap of Reeds sites were declining, and both sites were becoming overgrown with woody vegetation.
Table 1: Echinacea laevigata population changes at study sites. 1990 numbers from Gaddy
1990, Picture Creek 2002 numbers from Lundquist 2002. The 2004 estimates for Knap of
Reeds and the Eno River Diabase Sill populations are ours.
1990 2004 Rosettes/Flowering Rosettes/Flowering site stems stems Eno River Diabase Sill 1500/125 <500/25 Knap of Reeds Diabase Slopes 1000/200 <500/30 Picture Creek Diabase Barrens 2000/100 >100,000/10,000
Site descriptions
Picture Creek Diabase Barren(36°09’50.78”N, 78°44’19.43”W) has a thriving prairie community in a large power line ROW, with a remarkable density of smooth coneflower
(Figure 1), and large populations of Solidago ptarmicoides (Nuttall) Nesom, Symphyotrichum depauperatum (Fernald) Nesom, and Silphium terebinthinaceum Jacquin. These rare plants 6
are most dense in a 200m X 60m section of the ROW. Smooth coneflower and other rare forbs are also numerous in a nearby open woodland which was burned in 1994. The surrounding closed woods maintain a fairly diverse herb layer. The total size of the property is 550 acres, and is owned by North Carolina Department of Agriculture.
At the Eno River Diabase Sill(36°04’32.70N”N, 78°51’46.45”W), the majority of
Echinacea laevigata and other rare forbs are located along a 50 meter stretch of roadside.
Many of the species also persist in an adjacent woodland, where they rarely flower. This area had been cleared by volunteers in the past, but was becoming overgrown at the time of this study. Although the area included in this study is small (800 m2), at least 10 rare species are found at this location(Appendix A). This site has recently been acquired by the North
Carolina Department of Agriculture, Plant Conservation Program.
At Knap of Reeds Diabase Levee and Slopes(36°08’04.77”N, 78°47’37.88”W),
Echinacea laevigata and prairie associates are largely confined to a 10 X 100 meter area in an abandoned power line ROW. The smooth coneflowers are clustered throughout, and there is a large population of Silphium terebinthinaceum, and of Cirsium carolinianum
(Walter)Fernald&Schubert and Matelea decipiens (Alexander)Woodson. This site is owned by U.S. Army Corps of Engineers.
Methods
To determine if smooth coneflower and other prairie forbs form a persistent soil seed bank, we sampled the soil from the power line community at Picture Creek, as this is the largest and densest population of smooth coneflower and other prairie forbs, and where we 7
would most expect to find seeds in the soil. We also sampled in the surrounding woods, which aerial photos from 1955 show to have been open habitat where these prairie species may have occurred. This decision was later validated when we found several hundred rosettes of Echinacea laevigata while sampling. Finding seeds in the soil in these woods would suggest that they are persistent in the soil. We also sampled the soil seed bank from
Knap of Reeds Creek and Eno River Diabase Sill.
The majority of prairie species flower in the spring and summer and produce seeds after July. We collected soil samples in July, to allow for the germination of seeds produced the previous year and to minimize the input of current year seeds (Baskin and Baskin 1998).
Within the power line community at Picture Creek, a 50 meter by 150 meter sampling area was established which encompassed the densest concentration of prairie vegetation. Within this sampling area, we randomly established ten 50 meter transects. In the adjacent woods, ten additional randomly placed transects were established. At the Eno
River Diabase Sill, we established four 50 meter transects. One transect was established along the road in the highest density of prairie forbs, and an additional three in an adjacent woodland, where prairie forbs persisted. At the Knap of Reeds site, two transects were established in the power line.
Soil cores 2.5 cm in diameter and 10cm deep were extracted at every meter along each transect. The litter layer was purposely excluded from the soil seed bank sampling, as we were primarily interested in whether or not the seeds of these species persisted buried in the soil. The 50 cores from each transect were combined bagged together. This resulted in
26 bags and 1300 cores of soil from the 4 study sites. 8
To determine if viable seeds remain in the litter, we sampled the leaf litter in the power line community at Picture Creek. In November 2004 and April 2005, we randomly selected three of the previously established transects, and collected 20X20 cm litter samples every 2 meters, which totaled 1 square meter of litter for each transect. The litter for each transect was bagged together, resulting in three Fall samples and three Spring samples.
We employed the seedling emergence method developed by Ter Heerst et al. (1996) to assay our soil cores. Each bag of soil was sieved twice: first through a coarse sieve
(5mm), which eliminated large objects such as stones and twigs, and secondly with a fine sieve (.18mm), which was small enough to retain the smallest seeds(Juncus sp.), but removed most of the silt and clay particles. The remaining concentrated seed sample was then mixed with water and poured onto a very thin layer of sterile sand on top of sterile potting soil in a
20 X 50cm greenhouse flat. After processing, one greenhouse flat was sufficient for each transect, as the concentrated seed/soil mix was never deeper than the 5mm.
To test if the sieving process was detrimental to Echinacea laevigata seeds, one additional flat was prepared from 50 soil cores to which 25 smooth coneflower seeds were added prior to processing. These soil cores were taken from a compacted roadbed on diabase outside of the study area at Picture Creek. An additional 4 flats containing only the potting soil and sterile sand were prepared as a control. All flats were then placed in the greenhouse at North Carolina State University, where they were watered daily and randomly rearranged weekly on the greenhouse bench to reduce possible position effects. Each young seedling was removed from the germination flat and repotted until it could be identified. After germination stopped, the seed mixtures were recollected from the flats, cold stratified for 8 9
weeks, and then placed back in the greenhouse. After another 14 weeks, the remaining soil was checked for ungerminated seeds.
The six litter collections were sieved and processed exactly like the soil, and the resulting seed mix was poured into 6 identically prepared 20X50 greenhouse trays.
Germination began within days, and continued for 15 weeks. These samples were not recollected and cold stratified.
Analysis
We compared the seedlings recovered from the seed bank and the leaf litter to the prairie species listed in Appendix A. Poaceae, Juncaceae, and Cyperaceae species were not represented on the target list of forbs, and were identified only to the genus level.
Results
A total of 1175 seedlings were recovered from the soil samples from all sites(Appendix B). None of the prairie species listed in Appendix A were recovered.
Seventeen Echinacea laevigata seedlings were recovered from the tray spiked with 25 seeds.
This 64% seedling germination rate was consistent with coneflower seed viability found by other researchers (Gadd, pers. com.). No ungerminated seeds of any kind were found in the soil samples at the end of this study.
599(51%) of the seedlings were in the families Poaceae, Cyperaceae, and Juncaceae.
These consisted primarily of weedy species, such as crabgrass (Digitaria spp.), witchgrass(Dicanthelium spp,), rushes (Juncus spp.), and nutsedges(Cyperus spp.). 10
Of the remaining 576 seedlings, 545(94.6%) were identified confidently to the genus level, and 31(5.4%) died before they could be identified. A total of 34 genera from 19 families were recovered. The composite family was represented by 9 genera and 10 species.
The forb species most numerous in the seed bank were Eupatorium serotinum Michaux,
Verbascum thaspus Linnaeus, Mollugo verticillata Linnaeus, Pseudognaphalium obtusum
Linnaeus, Eupatorium capillifolium (Lamarck) Small, and Richardia scabra Linnaeus. The species composition of the seed bank from all study sites was similar. The most seedlings were recovered from the power line community at Picture Creek (65.4 per transect).
The leaf litter samples yielded a total of 1483 seedlings (Appendix C). The samples collected in the Fall comprised the majority (60%) of this total, 295 seedlings per transect, while those collected in the Spring accounted for 40% of the total, 199 seedlings per transect.
The majority (68%) of the seedlings from all litter samples were graminoids (Poaceae,
Cyperaceae, Juncaceae). Of the 475 other seedlings, 79% were identified as members of 29 genera. At least 2 rare species, Echinaceae laevigata (10 seedlings) and Solidago ptarmicoides (31 seedlings) were recovered in the litter.
Discussion
The protocol used for determining the seed bank composition succeeded in recovering a large number of seedlings from both the soil and litter samples. The process of screening the soil required by this protocol possibly damaged some seeds, however, smooth coneflower seeds submitted to this in the spiked control and germinated at a rate consistent 11
with rates reported by other researchers (Gadd pers com). We concluded that the soil processing methods did not damage the coneflower seeds or impair their ability to germinate.
None of the prairie species were recovered from the soil seed bank at any of the sampled sites. This was unexpected, particularly in the power line at Picture Creek Diabase
Barrens, given the density of the prairie forbs at this location and the intensity of sampling.
The failure to recover any of the target species strongly implies that they do not form persistent seed banks and that attempts to recruit new individuals from this source will not be successful. Prairie remnant seed banks hold little promise for restoration. This finding emphasizes the importance of properly managing these prairie remnants and arresting their decline.
Finding two of the targeted species (smooth coneflower and Solidago ptarmicoides) in the litter layer was not unexpected, as the large number of these two species in the above- ground community suggests that they would be prominent in the seed rain. Finding fewer seeds of both species in the Spring litter than in the Fall litter suggests that seeds of these species may be predated upon or lose viability over the winter. But the fact that they can persist through the winter implies that the litter layer itself could be used as a source of propagules for restoration efforts and should be considered when rescuing rare plants from imminent destruction.
The failure to recover seedlings of Echinacea laevigata or any other rare plants from the soil suggests that the dramatic increase in the population at Picture Creek Diabase
Barrens was not attributable to a persistent soil seed bank. Many of the prairie forbs at
Picture Creek are long lived perennials, several of which, including smooth coneflower, are 12
reported to persist for decades after canopy closure resulting from fire suppression (Frost
200). We suggest that power line ROW was constructed through a population of prairie plants suppressed by canopy closure, and were subsequently liberated as vegetative sprouts by the canopy removal.
The dominance of ruderal species in the seed bank at all sites was largely consistent with the findings of other seed bank studies in prairie communities. However, the flora of the seed bank does not appear to be a reliable predictor of response after conservation management. Since this study was completed, both the Eno River Diabase Sill and Knap of
Reeds Creek sites have received increased management, including prescribed fire. The smooth coneflower and other prairie forb populations have increased dramatically at each site. The ruderal seed bank dominants do not appear to have benefited from these management activities. 13
Bibliography
Alley, H. and J. Affolter. 2004. Experimental Comparison of Reintroduction Methods for the Endangered Echinacea laevigata (Boyton and Beadle) Blake. Natural Areas Journal 24(4):345-350
Apsit, V.J., & P.M. Dixon. 2001. Genetic Diversity and Population Structure in Echinacea laevigata (Boyton and Beadle) Blake, and Endangered Plant Species. Natural Areas Journal 21: 71-77.
Barden, L. 1997. Historic Prairies in the Piedmont of North and South Carolina, USA. Nat Areas J 117 (2): 149-152.
Barnett-Lawrence, M.S., 1993. Smooth Coneflower, Echinacea laevigata (Boynton and Beadle) Blake, Experimental Monitoring and Management for 1993. Unpublished report for NCDA Plant Conservation Program, Raleigh, NC.
Baskin, J.M., Baskin, C.C. 1988. Endemism in Rock Outcrop Communities of Unglaciated Eastern United States: An Evaluation. University of Georgia Press.
Baskin, Carol C., Jerry M. Baskin. 1998. Seeds Ecology, Biogeography, and Evolution of Dormancy and Germination. Academic Press, San Diego CA
Davis, J.E., C. McRae, B.L. Estep, L.S. Barden, J.F.Matthews 2002. Vascular Flora of Piedmont Prairies: Evidence from Several Prairie Remnants. Castanea 67:1-12
Emanuel, C.M. 1996. Silvicultural Options for Recovering the Endangered Smooth Coneflower, Echinacea laevigata (Boyton and Beadle) Blake. Masters Thesis. Clemson University.
Evans, R.E., M. Pyne, & S. Hiltner. 2002. Remnant Diabase Vegetation in the North-Central North Carolina Piedmont. Presented by NatureServe for the 3rd Eastern Native Grass Symposium, Chapel Hill, NC.
Franklin, Misty A., J.T. Finnegan 2006. Natural Heritage Program List of Rare Plant Species of North Carolina. Raleigh, NC.
Frost, Cecil Carlyle. 2000. Studies in Landscape Fire Ecology and Presettlement Vegetation of the Southeastern United States. Phd Dissertation. University of North Carolina, Chapel Hill 14
Gadd, L.E. 2006. Pollination Biology of the Federally Endangered Echinacea laevigata (Boynton and Beadle) Blake, Smooth Coneflower, In Small, Isolated Populations. Maters Thesis. North Carolina State University, Raleigh, NC.
Gaddy, L.L. 1991. The Status of Echinacea laevigata (Boyton and Beadle) Blake. Unpublished report to the U.S. Fish and Wildlife Service. Asheville, NC 24 pp.+ appendives and maps.
Havercamp, Jennifer., Gordon G. Whitney. 1983. The Life History of Three Ecologically Distinct Groups of Forbs Associated with the Tallgrass Prairie. American Midland Naturalist, 109, No. 1
Johnson RG and Anderson RC. 1986. The seed bank of a Tallgrass prairie in Illinois. American Midland Naturalist 115(1):123-30.
Laughlin DC. 2003. Lack of Native Propagules in a Pennsylvania, USA, Limestone Prairie Seed Bank: Futile Hopes for a Role in Ecological Restoration. Natural Areas Journal 23(2):158-64.
Leuszler, H. K., V.J. Tepedino, and D.G. Alston. 1996. Reproductive Biology of Purple Coneflower in Southwestern North Dakota. The Prairie Naturalist 28(2).
Lundquist, E. 2001. Monitoring report for Echinacea laevigata at Picture Creek Diabase Barrens. Prepared for NCDA Plant Conservation Program, Raleigh, NC
McGregor, R.L. 1968. The taxonomy of the genus Echinacea (Compositae). University of Kansas Science Bulletin 48: 113-142.
Murdock, N.A. 1992. Endangered and threatened wildlife and plants: Echinacea laevigata (Smooth Coneflower) determined to be endangered. Federal Register 57:46340-46344
Murdock, N.A. 1995. Recovery Plan for Smooth Coneflower (Echinacea laevigata). Prepared for the U.S. Fish and Wildlife Service.
Oakley, Shawn C., H.E. LeGrand, JR., M.P.Schafale 1995. An Inventory of Mafic Natural Areas In The North Carolina Piedmont. North Carolina Natural Heritage Program, Raleigh, NC.
Peters, M. 2005. Genetic analysis of the federally endangered Echinacea laevigata using amplified fragment length polymorphisms (AFLP)—Inferences in population genetic structure and mating system. Masters thesis. North Carolina State University. 15
Rabinowitz D. 1981. Buried Viable Seeds in a North-American Tall-Grass Prairie - the Resemblance of Their Abundance and Composition to Dispersing Seeds. Oikos 36(2):191-5.
Thompson, K. 1987 Seeds and Seed Banks. New Phytologist 106(Suppl.)
Schafale, M. P. and A. Weakley. 1990. Classification of the Natural Communities of North Carolina. 3rd Approximation. North Carolina Natural Heritage Program.
Schafale, M.P. 2003. Classification of the Natural Communities of North Carolina. 4rth Approximation. Unpublished report.
Slapcinsky, J. 1994. The Vegetation and soils associated with Diabase in Granville and Durham Counties, North Carolina. Masters thesis. North Carolina State University, Raleigh, NC.
Smith, C.W. 1986. The occurrence, distribution, and properties of dispersive soil and saprolite formed over diabase and contact metamorphic rock in a Piedmont landscape in North Carolina. Masters Thesis. North Carolina State University, Raleigh, NC.
Ter Heerdt G.N.J., G.L. Verweij, R.M. Bekker, J.P. Bakker. 1996. An Improved Method for Seed-Bank Analysis: Seedling Emergence After Removing the Soil by Sieving. Funct Ecol 10(1): 144-151.
16
APPENDICES
17
Appendix A
State and federal ranking of rare species found at three study sites, as reported in the Natural
Heritage Program List of Rare Plant Species of North Carolina 2006. Species presence at a site indicated by X. PCDB= Picture Creek Diabase Barrens, ERDS= Eno River Diabase Sill,
KOR= Knap of Reeds Creek Diabase Slopes.
S G
Species rank rank State Federal PCDB ERDS KOR
Echinacea laevigata S1 G2 E-SC LE X X X
Baptisia australis var. aberrans S2 G5T2 T X X
Berberis canadensis S2 G3 SR-T X
Cardamine douglassii S2 G5 SR-P X X
Cirsium carolinianum S2 G5 SR-P X X
Clematis ochraleuca S3 G4 W6 X X
Delphinium exaltatum S2 G3 E-SC FSC X X
Eupatorium godfreyanum S2 G4 SR-P X X
Liatris squarrulosa S2 G5 SR-P X X X
Lithospermum canescens S2 G5 SR-P X X X
Acmispon helleri S3 G5 SR-T X
Marshallia sp.1 S1 G1 SR-L FSC X
Matelea decipiens S2 G5 SR-P X X X
Nestronia umbellata S3 G5 W1 X
Solidago ptarmicoides S1 G5 E X
Solidago rigida var. glabrata S2 G5T3 SR X
Parthenium auriculatum S2 G3 SR-T X X 18
Ruellia humilis S1 G5 T X X
Ruellia purshiana S2 G3 SR-O X
Scutellaria leonardii S2 G4 SR-P X
Silphium terenbinthinaceum S2 G4 SR-P X X X
Symphyotrichum depauperatus S1 G2 SR-D X
Symphyotrichum laevis var. con S2 G5T4 SR-P X
Symphyotrichum parviceps S1 G5 X
Trichostema brachiatum S2 G4G5 SR-P X
Porteranthus stipulatus S2 G5 SR-P X
19
Appendix B
Species recovered from the soil seed bank from all study sites. Numbers are averages from all transects from that site, standard deviation in parentheses.
species Picture Creek Picture Eno River Knap of
Powerline(n=10) Creek Diabase Reeds
Woods(n=10) Sill(n=4) Diabase
Slopes(n=2)
Unknown Forb 0.9 (0.88) 0.9 (1.45) 2.5 (0.35) 1.5 (1.5)
Acalypha rhomb. 0 (0) 0.2 (0.42) 0.25 (0.5) 0.5 (0.5)
Acer rubrum 0 (0) 0 (0) 0.25 (0.5) 0 (0)
Antennaria sp. 0.3 (0.95) 0 (0) 0 (0) 0 (0)
Cardamine hirs. 1 (2.21) 0.2 (0.42) 0.25 (0.5) 0 (0)
Conzya can. 0 (0) 0.5 (1.08) 0 (0) 0 (0)
Cyperaceae sp. 9.6 (4.88) 5.2 (9.51) 4 (3.37) 2.5 (2.5)
Desmodium sp. 0 (0) 0.1 (0.32) 0 (0) 0 (0)
Dicanthanthelium 5.6 (2.01) 4.2 (1.99) 5 (4.76) 7 (0) spp.
Digitaria spp. 7.4 (10.52) 0.1 (0.32) 2.5 (3.32) 0.5 (0.5)
Duchesnia ind. 0.2 (0.63) 0.4 (0.7) 0 (0) 0 (0)
Erechtites hier 0.5 (0.71) 0.3 (0.48) 0.5 (0.58) 0.5 (0.5)
Eupatorium cap. 1.2 (1.32) 1.5 (1.43) 1.5 (1.29) 0.5 (0.5)
Eupatorium ser. 6.2 (4.64) 0.5 (0.71) 3.25 (2.75) 2.5 (2.5)
Euphorbia sp. 0.9 (1.45) 0 (0) 0 (0) 1 (1)
Gallium sp 0 (0) 0 (0) 0 (0) 0.5 (0.5)
Pseudognaph obt. 4.9 (2.02) 1.4 (1.58) 2 (0.82) 0 (0) 20
Hieracium ven. 0 (0) 0.1 (0.32) 0 (0) 0 (0)
Houstonia long. 1.7 (2.21) 2 (3.89) 2.75 (0.5) 0.5 (0.5)
Hypericum punct 0.4 (0.97) 0.4 (1.26) 0.5 (1) 0.5 (0.5)
Hypericum strag 0.5 (0.85) 0.1 (0.32) 0 (0) 0 (0)
Juncus tenuis 6 (8.06) 8 (16.35) 10 (2.71) 5 (5)
Leersia virginica. 0 (0) 0.2 (0.42) 0 (0) 0 (0)
Lespedeza cun. 1.4 (0.97) 0 (0) 0.75 (0.96) 0 (0)
Ludwigia alt. 0 (0) 0.1 (0.32) 0.25 (0.5) 0 (0)
Liatris sp. 0.1 (0.32) 0 (0) 0 (0) 0 (0)
Morus rubra 0 (0) 0.1 (0.32) 0 (0) 0 (0)
Mollugo vert. 4.9 (3.75) 0 (0) 1.25 (1.5) 6 (3)
Oenothera frut. 1.7 (2) 0.2 (0.63) 0.25 (0.5) 0 (0)
Paulownia tom. 0.1 (0.32) 0 (0) 0 (0) 0 (0)
Physalis sp. 0.1 (0.32) 0 (0) 0.25 (0.5) 0 (0)
Phytolacca amer. 0 (0) 0.1 (0.32) 0 (0) 0 (0)
Pluchea camph. 0 (0) 0 (0) 0.25 (0.5) 0 (0)
Poacaeae sp. 0.6 (0.7) 0.2 (0.63) 2 (0.82) 2 (1)
Polypremum pro. 0.1 (0.32) 0.1 (0.32) 0.25 (0.5) 0 (0)
Rhus coppalinum 0.1 (0.32) 0.1 (0.32) 0.25 (0.5) 0 (0)
Richardia sca. 2.4 (3.03) 0.6 (0.97) 0 (0) 0 (0)
Solanum nig. 0.1 (0.32) 0.3 (0.67) 0 (0) 0 (0)
Verbascum thas. 6.2 (6.92) 0 (0) 4 (1.15) 0 (0)
Verbena simplex 0.2 (0.42) 0.8 (1.32) 0.25 (0.5) 0 (0)
Verbesina alt. 0 (0) 0 (0) 0 (0) 0 (0)
Viola sp. 0.1 (0.32) 0 (0) 0 (0) 0 (0) 21
Appendix C
Species recovered from Litter samples. Mean is the average from 3 transects.
Fall 2005 Spring 2006
species Mean std Mean std
Poaceae app.. 123.00 29.14 103.00 28.62
Dicanthelium spp. 41.67 34.24 41.33 5.86
Cyperaceae spp. 20.33 9.02 0.00 0.00
Juncaceae spp. 1.00 1.73 5.67 8.96
Liriodendron tulipifera. 1.00 1.00 0.67 0.58
Solidago sp. 30.67 11.06 3.33 5.77
Liatris sp. 1.00 1.73 0.33 0.58
Lespedeza cuneata 8.33 9.24 7.67 5.86
Cassia sp. 3.67 3.06 0.67 1.15
Solanum nigrum 1.67 1.53 0.33 0.58
Acalypha rhomboidea 2.00 2.00 1.00 0.00
Oenothera fruticosa 2.00 1.73 0.33 0.58
Pseudognaphium obtusifolium. 1.67 1.15 2.33 2.52
Eupatorium serotinum 1.33 1.15 2.00 2.00
Verbascum thapsus 1.00 0.00 1.33 0.58
Houstonia longifolia 8.67 6.43 3.67 3.51
Echinacea laevigata 2.33 1.53 1.00 1.73
Pinus taeda 0.67 0.58 0.67 0.58
Ludwigia alternifolia 0.33 0.58 0.00 0.00
Eupatorium capillifolium 1.00 1.00 1.00 1.00
Desmodium sp. 2.33 3.21 1.67 2.89 22
Rhus copallinum 0.33 0.58 0.33 0.58
Solidago ptarmicoides 6.67 6.03 3.67 4.04
Richardia scandens 1.00 1.73 0.67 1.15
Viola sp. 2.00 3.46 0.00 0.00
Acer rubrum 0.33 0.58 0.00 0.00
Erechtites hieracifolia 1.33 2.31 6.00 2.65
Hypericum punctatum 0.67 1.15 0.33 0.58
Verbena simplex 0.33 0.58 0.00 0.00
Conzya canadensis 0.33 0.58 0.67 1.15
Phytolacca americana 0.00 0.00 0.67 1.15
Gallium sp. 0.00 0.00 0.33 0.58
Rhyncosia tomentosa 0.00 0.00 0.33 0.58
Baccharis halimifolia 0.00 0.00 0.33 0.58
Unknown forb spp. 26.33 20.55 12.00 5.66