Rare and Endangered Vascular Plants of North Carolina's

Rare and endangered vascular plants of

North Carolina's Outer Banks, Emerald

Island to Virginia; a case for conservation and preservation

R. Stalter and E. Lament Department of Biological Sciences, St. John's University

8000 Utopia Parkway, Jamaica, New York 11439

Abstract

The vascular flora of the Outer Banks, Emerald Island to Virginia, consists of 806 species within the 422 genera and 140 families. Eighteen species occurring on the Outer Banks are listed as rare or endangered in North Carolina. Amaranthus pumilus is listed as federally threatened. This number of rare plant species is one of the highest for any area of equal size in North Carolina. Species of foreign origin, though numerous in the flora, are nonetheless only a minor component of the natural vegetation.

1 Introduction

The Outer Banks consist of a chain of Atlantic Ocean barrier islands, extending from Virginia southward along the northern half of the

North Carolina coast. The width of the islands ranges from 700 feet (213 m) at Sandy Bay to over 2 miles (3.2 km) in the vicinity of Buxton. The topography is relatively flat along most of its length, with an elevation of less than 5 feet (1.5 m) above mean sea level; however, beach dunes range from approximately 10 feet (3 m) to 30 feet (9 m) in height. Undulating dune fields are found elsewhere on the islands and the highest topography reaches 115 feet (35 m) at Jockey's Ridge.

4 Environmental Coastal Regions

The 160 mile (258 km) long series of islands surveyed in this floristic study include Bodie, Pea, Hatteras, and Ocracoke Islands,

located in Currituck and Dare counties (35 3(W Lat, 75 30*W Long.) and Portsmouth Island, Core Banks, Barker's Island, and Emerald Island in Carteret County. The earliest floristic inventory of the area

was conducted by Kearney*, who reported 136 species of vascular plants from Ocracoke Island. A lapse infloristi c collecting ensued

during the next 50 years. A second floristicinventor y of Ocracoke Island was conducted by Rondthaler®, who reported 106 species from

the island. Brown^ reported 313 species of vascular plants from the Outer Banks, but did not collect voucher specimens. Burk* conducted a comprehensive ecological study of the

Outer Banks and presented a voucher-based checklist of 565 vascular plant species. The most comprehensive floristic inventory of the

Outer Banks was that of Stalter and Lamont*'*° who presented an annotated list of 806 species. Four naturally-occurring plant communities have been

described from the Outer Banks by Stalter and Lamonf: 1) dune grass community, dominated by Uniola paniculata, Spartina patens,

Ammophila breviligulata., Panicum amarulum, and P. atnarum, occurring on sites which are exposed to salt spray but not inundated; 2) shrub community, dominated by Juniperus virginiana, Quercus

virginiana, Myrica cerifera, and Ilex vomitoria, occurring on sites which are less exposed to salt spray than the previous one; 3) pine- oak-hickory community, dominated by Pinus taeda in association with

several species of Carya, Quercus falcata, Q. nigra, and Liquidambar styraciflua, occurring on sites exposed to little or no salt

spray or inundation; and 4) tidal-marsh community, dominated by Spartina alterniflora, S. patens, and Juncus roemerianus, occurring on sites exposed to periodic tidal inundation. The sounds, freshwater

pools and ponds, roadsides, and abandoned fields in the vicinities of habitations support less extensive though different plant communities.

2 Methods

Collecting trips were made to the study area approximately once a month during the growing seasons from June 1989 through October 1996. Objectives for each trip included the collection of voucher

specimens and accumulation of information on abundance and apparent habitat preference for each species. Rare or endangered

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plants were determined by consulting Amoroso*, More than 2,400 specimens form the basis for this study. Taxonomically problematic specimens were sent to various experts for annotation; see Stalter and Lamonf ^ for a list of those who assisted in plant identification. A complete set of voucher specimens has been deposited at the herbarium at Cape Hatteras National Seashore, Manteo, North Carolina and Cape Lookout National Seashore, Marker's Island, North Carolina. Partial duplicate sets have been deposited in the herbaria of Brooklyn Botanic Garden (BKL), University of Michigan (MICH), Missouri Botanical Garden (MO),

New York Botanical Garden (NY), New York State Museum (NYS), and Academy of Natural Sciences of Philadelphia (PH) Published reports by earlier investigators of the few species we were unable to collect have been included in the checklist with the statement "not recently observed", accompanied by a literature citation; in these cases we have not examined the original voucher specimens. Nomenclature primarily follows Radford et al/ but recent taxonomic revisions were consulted to update the nomenclature in this flora. In most cases nomenclature presented in this flora agrees with

Kartesz* but when differences occur, the name as presented in Kartesz* is listed as a synonym and enclosed in brackets.

3 Discussion

The vascular flora of the Outer Banks, from Emerald Island to Virginia, consists of 806 species within 422 genera and 140 families. More than six-hundred forty species, or greater than 80% of the flora, are native to the region. A statistical summary is given in Table 1. The major families include the Poaceae (123 species), Asteraceae (88), Cyperaceae (71), and Fabaceae (38); over 25% of the species comprising the total flora are contained in the Poaceae and Asteraceae. Other large families are the Apiaceae (18 species),

Caryophyllaceae (17), Polygonaceae (17), and Brassicaceae (15). The largest genus is Panicum s. lat. (20 species), followed by Cypenis (18), Juncus (14), Carex (13), and FAeocharis (11). Six hundred and sixty-six species are non-woody (82% of theflora) , which underscores the generally graminoid and herbaceous appearance of the flora on the

Outer Banks.

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Table 1. Statistical summary of the vascular flora of the Outer Banks from Emerald Island to Virginia. Data from Stalter and Lamonf ^.

Fern Ferns Conifers Dicots Monocots Total Allies Families 18 9 101 27 140 Genera 183 290 120 422 Species 1 10 6 511 278 806

Thirty-seven species of southern affinities reach their northern

range limit on the Outer Banks (Table 2), whereas only four northern species (Ammophila breviligulata, Hudsonia tomentosa, Myrica

pennsylvanica, and Polygonum proliflcum) reach their southern limit on the Banks^. Polygonum prolifwum (determination verified by R S Mitchell [NYS]) is a new state record for North Carolina,

Eighteen species occurring on the Outer Banks are listed as rare or endangered in North Carolina*, while Amaranthus pumilus is

listed as federally threatened. Plants are rare, threatened or endangered for a multiplicity of reasons. Some plants are rare because they exist at the edge of their normal range; Ipomoea stolonifera and Hudsonia

tomentosa are two examples. Other plants are rare because they have narrow habitat requirements that are met in only a few areas of the

state or world (Amaranthus pumilus and Polygonum glaucum). Natural biological events (plant succession) climatic events (drought, hurricanes, severe cold) and geological events (earthquakes,

volcanoes) can reduce the number of species, especially plants in restricted habitats. Additional factors that contribute to the rarity of

species are disturbance or loss of habitat from human-induced activities such as development, road building, introduction of exotic (non-native) plants and pests, over collection of useful or attractive

plants (Malaxis spicata, Uniola paniculata) and pollution. Occasionally , common plants are protected by state or federal law. One such species, Uniola paniculata, sea oats, is the

most common plant on the primary dune system, the dune system closest to the ocean. Sea oats can tolerate high concentrations of salt

spray that is carried to dunes from the ocean by prevailing winds. Sea oats, at times, may comprise almost 100 percent of the vegetation on the ocean-facing side of the primary dune. In spite of its abundance,

Uniola paniculata is a threatened species protected by North Carolina law because this rhizomatous perennial grass is an excellent dune stabilizer and dune builder. Before sea oats was protected, tourists

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would harvest the attractive inflorescences which were taken home to be used in floral displays. Picking the inflorescences reduced the amount of seed for regeneration and the pulling and trampling associated with this unnatural harvesting killed or weakened the plant. Once the plant was killed, the fragile dune system was ravaged by

erosion. In the United States, sea oats is protected in coastal environments from Texas to Virginia. To protect rare or "threatened" plants, comprehensive field

surveys, intensive statewide biological inventories, natural area protection and stewardship programs will provide a comprehensive

plan for conservation of rare species and their present or potential habitat. The establishment of state and national plant lists including a species threatened with extinction throughout all or a significant

portion of their range or "threatened" (a species likely to be endangered within the foreseeable future throughout all or a

significant portions of its range) will enable scientists to monitor the rare, endangered or threatened species and protect them. Knowledge of their existence and inventory of their distribution will assist in

maintaining their populations. Eighteen species occurring on the Outer Banks are listed as

rare or endangered in North Carolina*: Amaranthuspumilus (listed as Federally threatened), Eleocharis cellulose*, E. halophila, E. montevidensis, E. rostellata, Helianthemum corymbosum, Hottonia

inflate*, Hudsonia tomentosa, Ipomoea stolonifera, Leptochloa fascicularis var. maritima, Lilaeopsis caroliniensis, Ludwiga alata,

L lanceolota, Malaxis spicata, Polygonum glaucum, Quercus minima, Rhynchospora odorata and Spiranthes laciniata. This

number of rare plant species is one of the highest for any area of equal size in North Carolina. Species of foreign origin, though numerous in the flora, are

nonetheless only a minor component of the natural vegetation and occur principally in ruderal sites, lawns, and along the edges of trails and roads. The introduction of numerous species of grasses (Poaceae)

is especially noteworthy in the flora. Undoubtedly, exotic species will continue to invade and become established on the Outer Banks as the

human population grows and traverses the islands, scattering seeds and creating new open habitats of disturbance. The introduction of exotic plants may contribute to the loss of rare and endangered plants

in the Outer Banks of North Carolina.

Table 2. Species of southern affinities reaching their northern range limit on the Outer Banks, North Carolina. Data from Stalter and

Aeschynomene indica Lactuca graminifolia

Apium leptophyllum Ludwigia maritima

Bulbostylis barbata Ludwigia microcarpa

Chloris petraea Ludwigia repens

Corydalis micrantha Oplismenus setarius

subsp. australis

Croton punctatus Opimtia dnimmondii

Cynanchum angustifolium Pariataria floridana

Cyperus sesquiflorus Paspalum notatum

Daubentonia punicea Portulaca pilosa

Dichromena latifolia Primus caroliniana

Eleocharis cellnlosa Rhynchospora baldwinii

Eleochahs montevidensis Rhynchospora odorata

Gaura angustifolia Sabal minor

Sisyrinchium rosulatutn Habenaria repens

Helianthemum corymbosum Smilax auriculata

Hydrocotyle bonahensis Spermolepis divaricate*

Hex cassine Stenotaphrum secundatum

Yucca aloifolia Ipomoea sagittata

Ipomoea stolonifera

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References

1. Amoroso, J.L.I 997. Natural Heritage Program list of the

rare plant species of North Carolina Natural Heritage Program, Division Parks and Recreation, Dept. Environment. Health & Natural Resources, Raleigh. 88 p.

2. Brown, C A. 1957. Botanical reconnaissance of the Outer

Banks of North Carolina. Technical report No. 8, Part C, Coastal Studies Institute, Louisiana State University, Baton

Rouge, LA. 179 p.

3. Brown, C A 1959. Vegetation of the Outer Banks of North

Carolina. Coastal Studies Series No. 4, Louisiana State University, Baton Rouge, LA 179 p.

4. Burk, C.J. l96l.Afloristic study of the Outer Banks of North Carolina. Unpublished PhD. Dissertation, University

of North Carolina, Chapel Hill, NC. 123 p.

5. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd ed.Volume 1 - Checklist. Timber Press, Inc. Portland, OR

6. Kearney, TH 1900. The plant covering ofOcracoke Island: A study in the ecology of the North Carolina strand

vegetation. Contributions to the U.S. National Herbarium

7. Radford, A.E., HE Ahles, and CR Bell. 1968. Manual of the vascular flora of the Carolinas. Univ. North Carolina Press, Chapel Hill, NC. 1183 p.

8. Rondthaler, A.K. 1952. Flowering plants ofOcracoke Island, North Carolina. Unpublished B A Thesis, Reed College,

Portland, OR. 39 p.

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9. Stalter, R. and E.E. Lament. 1997, Flora of North Carolina's

Outer Banks, Ocracoke Island to Virginia. J. Torrey Hot. Soc. 124:71-88.

10. Stalter, R and E E Lament. 1997. Flora of Cape Lookout National Seashore and Emerald Isle, North Carolina.

Bartonia (in press).