Fire Effects Information System (FEIS)
FEIS Home Page

Index of Species Information

SPECIES:  Uniola paniculata
Seaoats in flower. Image by Kenneth M. Gale, .


SPECIES: Uniola paniculata
AUTHORSHIP AND CITATION: Walsh, Roberta A. 1994. Uniola paniculata. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: []. Revisions: On 24 October 2018, the common name of this species was changed in FEIS from: sea oats to: seaoats. Images were also added. ABBREVIATION: UNIPAN SYNONYMS: NO-ENTRY NRCS PLANT CODE: UNPA COMMON NAMES: seaoats TAXONOMY: The scientific name of seaoats is Uniola paniculata (Poaceae) L. [10,14,29]. There are no currently accepted infrataxa. LIFE FORM: Graminoid FEDERAL LEGAL STATUS: No special status OTHER STATUS: NO-ENTRY


SPECIES: Uniola paniculata
GENERAL DISTRIBUTION: Seaoats occurs along the mainland coast and barrier islands from Northampton County, Virginia, through Florida [14]. It continues west along the Gulf coast through Texas and south to Tabasco, Mexico [11]. It is also widely distributed in the Bahama islands and occurs on some sandy areas of the northwestern coast of Cuba [2,4,10,21].
Distribution of seaoats in the United States. Map courtesy of USDA, NRCS. 2018. The PLANTS Database. National Plant Data Team, Greensboro, NC. [2018, October 24] [27].
   FRES16  Oak - gum - cypress
   FRES41  Wet grasslands


   K078  Southern cordgrass prairie
   K090  Live oak - sea oats


Seaoats is listed as a dominant in the following published

Plant communities of Texas (Series level) [25]

Besides those listed in the Kuchler Plant Associations, common
associates of seaoats include beach purslane (Sesuvium portulacastrum),
goatfoot morning glory (Ipomaea pes-caprae), railroad vine (Ipomaea
stolonifer), sea rocket (Cakile edentula), evening primrose (Oenothera
humifusa), beach spurge (Chamaesyce bombensis), beach sunflower
(Helianthus debilis), seashore-elder (Iva imbricata), beach dropseed
(Sporobolus virginicus), beach berry (Saevola plumieri), and bay cedar
(Suriana maritima) [3,15,23,26].


SPECIES: Uniola paniculata
IMPORTANCE TO LIVESTOCK AND WILDLIFE: Cattle graze seaoats [16]. Most seaoats spikelets falling on stable sites (and therefore not rapidly buried by sand) are eaten by birds and mammals [16]. On the east coast of Florida, the oldfield mouse inhabits barrier island dunes. It is found in open habitats of seaoats fore dunes and it feeds on seaoats fruits [15]. On Perdido Key, Florida, ideal habitat for the endangered Perdido Key beach mouse consists of well-developed dunes vegetated with seaoats and other dune grasses. The Perdido Key beach mouse lives in burrows constructed in the dunes. It feeds primarily on seeds of beach herbs, including seaoats, and insects [7]. Marsh rabbits feed on seaoats in the dune areas of the barrier islands of Georgia. Songbirds, especially song sparrows and other fringillids, and red-winged blackbirds are the major consumers of seaoats seeds [16]. PALATABILITY: NO-ENTRY NUTRITIONAL VALUE: Seaoats has essentially no forage value for livestock [9]. COVER VALUE: NO-ENTRY VALUE FOR REHABILITATION OF DISTURBED SITES: Seaoats was used in experimental dune building and vegetative stabilization on Timbalier Island, Louisiana, a barrier island which is sand-deficient. Sand fencing was used to stimulate sand accretion on a washover terrace breached in 1979 during a storm surge. Fencing and vegetation planting was begun May 1981, and the site was fertilized in late September 1981. Seaoats was planted in November 1981, between already planted bitter panicum (Panicum amarum). Seaoats had a 25 percent survival rate in May 1982, and a 23 percent survival rate by August 1982. Sand accumulation on the sand-fenced and vegetated areas was substantial over a 3-year period (1981-1984). Without sand fencing vegetation did not cause appreciable vertical accretion of sand [19]. Seaoats is used in Florida to enhance beach stability when lost sand is replaced. Replacement sand is shaped and then planted with seaoats and other pioneer species to begin the dune-building process [28]. OTHER USES AND VALUES: NO-ENTRY OTHER MANAGEMENT CONSIDERATIONS: Seaoats is an excellent dune builder and sand binder. It thrives in areas where dune building is active [23] and contributes to maintenance of the dune in its position. Seaoats traps windblown sand, forming mounds of sand which increase as the plant responds with increased growth [15]. It possesses an extensive root and rhizome system which produces new growth following sand burial [4]. Seaoats is well adapted to and dominates the most exposed areas of the dune where soil moisture is low. It tolerates drought, salt spray, and rapid sand burial. Maximum leaf elongation occurs at 12.8 percent soil moisture. Stomates close and leaf elongation slows when soil moisture falls below 8.5 percent. Plants do not wilt until soil moisture falls below 1.2 percent. Once drought is relieved, seaoats can recover from very negative water potentials. Excessive soil moisture from a high water table or inundation has a greater negative effect on seaoats growth than does low soil moisture. With waterlogging stress due to a high water table, stomates close and there is reduced biomass production. Inundation of roots for just a few days results in death of the plant [12]. Erosion of dunes is accelerated by grazing. When sand on the windward slope is not anchored by seaoats and other vegetation it is carried over the top by the wind and deposited on the lee side, resulting in migrating or "marching" dunes. When overgrazing results in the loss of dune vegetation and the subsequent loss of the stable dune system, a wide, flat beachfront may develop. Then extremely high storm induced tides may inundate the entire beachfront and erode the older, well-established dune systems protecting the interior, as occurred on Cumberland Island, Georgia in 1971. Grazing has transformed several of the banks in North Carolina into barren islands of shifting sand. Dune damage from grazing has also been reported from South Carolina, Texas, and several islands along the Georgia coast [16]. Vegetation on North Padre Island, Texas, is still recovering from cattle grazing from 1850 to 1971, when it was discontinued [1]. Seaoats is adversely affected when the dunes on which it grows are altered by urban development, by the impact of off-road vehicles on vegetation cover and compaction of soil, and by pollution of adjacent waters by treated and untreated sewage, fertilization, and contaminants from marinas, fish processing plants, and highways [23]. Seaoats was grown under greenhouse conditions in Louisiana dune sand. Addition of the macronutrients nitrogen, phosphorus, and potassium resulted in significantly greater leaf-elongation rates, number of stems, and aboveground biomass than in controls with no additions. However, additions of the micronutrients iron, manganese, copper, and zinc in conjunction with the macronutrients led to reduced leaf elongation and number of stems compared to controls. Micronutrients alone had no positive or negative effects [13]. Seaoats seedlings were outplanted to Miami Beach, Florida, beaches to enhance beach stability. When seedlings were inoculated with vesicular-arbuscular (VAM) fungi there were increases in seedling growth over those that were not inoculated. Root colonization by VAM fungi was higher when the inoculum was already-colonized roots rather than spores alone [28].


SPECIES: Uniola paniculata
GENERAL BOTANICAL CHARACTERISTICS: Seaoats is a native, perennial, semitropical, rhizomatous C4 grass [12,14]. Culms are stout and 3.3 to 6.6 feet (1-2 m) tall [2,4]. Leaves are both basal and cauline; leaf blades are up to 24 inches (60 cm) long. The inflorescence is a narrow condensed panicle 8 to 20 inches (20-50 cm) long [21]. Spikelets are very flat, 10- to 20-flowered, and 0.6 to 1.2 inches (1.5-3.0 cm) long [2,14]; they disarticulate below the glumes and fall entire. The fruit is a caryopsis [10]. Rhizomes are elongated and extensively creeping [2,14], readily rooting at the nodes when buried by sand [4]. Seaoats develops a dense concentration of surface roots as well as a penetrating system of deep roots [12]. RAUNKIAER LIFE FORM: Hemicryptophyte Geophyte REGENERATION PROCESSES: Seaoats sprouts from rhizomes and from perennating buds at the bases of culms [14]; growth and tillering is stimulated by sand burial [15], and new shoots and roots arise from the nodes of both rhizomes and aerial stems [5]. Seaoats also reproduces by seed [10]. Seaoats is wind pollinated. Florets open and close in the early morning; they open only once. Cross-pollination may be required for seaoats to produce an appreciable number of seeds. The very small seaoats populations on the Louisiana coast west of the Mississippi Delta produce average seed numbers of 0 to 9.53 per culm, depending on the population. Seeds that are produced have high germination rates [11]. Seaoats shows a trend toward lower seed production with decreasing latitude. Seeds from Bogue Bank, North Carolina, produced an average of 2.24 seeds per spikelet, which was about 30 percent of pollinated ovaries; the remaining ovaries aborted. In southern Florida 0.6 seeds per spikelet were found [11]. Seaoats spikelets are rapidly disseminated by wind, and are usually soon buried where sand is accreting [6]. Wind, ocean currents, and animals may disperse seeds to island and mainland beaches [3,15]. In storms, seeds and plant parts can be carried great distances [20]. The cold treatment required to break seed dormancy decreases southward along the range of seaoats, and is nonexistent for the south Atlantic coast Florida populations. Seeds from North Carolina gave optimal germination when cold-layered moist for 30 days at 40 degrees Fahrenheit (4.4 deg C) before being given an alternating thermoperiod (conditions of no light and alternating temperatures of 65 degrees Fahrenheit [18.3 deg C] for 17 hours followed by 95 degrees Fahrenheit [35 deg C] for 7 hours). No cold and/or moist treatment was required for seeds from Louisiana; room temperature treatment gave highest germination, but moist cold (40 degrees Fahrenheit [4.4 deg C]) pretreatment gave rates almost as high. Exposure of seeds to 30 days of dry cold at 40 degrees Fahrenheit (4.4 deg C) adversely affected germination. Louisiana seeds collected October 1981 and tested in April 1982 had germination rates of 78.0 to 88.8 percent under the alternating thermoperiod described above [11]. Seedlings establish during the first growing season and produce extensive tillers by the second season [16]. SITE CHARACTERISTICS: Seaoats is found on upper beaches, dunes, and loose sands near seashores in the southeastern United States [2,4,10,14,15,21,29] but it is seldom found in the forb zone of lower beaches [26]. Seaoats is one of the most important grasses on dunes and continuous dune ridges [15] because it helps build and maintain the sites on which it grows. Seaoats is dominant on the ocean facing part of fore dunes, often dominant at the top of the more stable second dune system, and much less prominent in the depression between the two [1,15,16,23]. This reflects the close zonal relationship of seaoats to the deposition of salt spray. On Bogue Bank, North Carolina, seaoats was dominant where salt spray was greatest. The highest salt concentration was on the windward side of the fore dune; the crest of the rear dune had a somewhat lower concentration, and the depression between the dune systems received much less salt depostion [20]. Seaoats sites have in common exposure to wind, salt spray, storms, drought [1], often deep and shifting sand, and occasional fires and salt water inundation. These unstable habitats suffer wind and water erosion. The soil has low water retaining ability and excellent drainage. Evaporation rates are high due to constant air movement, high temperatures, and full sunlight [20]. Seaoats is found on the Upper Keys of Florida, where sands are of coral origin, and on the Lower Keys which are limestone and have carbonate sands. The Atlantic seaboard beaches and dunes have siliceous sands. Soils of the Gulf Coast islands are fine to medium sand, with almost no organic content. On Cat Island, Texas, the organic content of the soil in the seaoats zone was measured at 0.07 percent [20]. Soils on the Coastal Plain are strongly leached, rich in aluminum and iron oxides, and usually deficient in many nutrients. However, salt spray carries some essential micronutrients to beach and dune plants [13,23]. Seaoats occurs on sands with the following reactions: Bogue Bank, North Carolina, pH 7.4 to 7.9; Jupiter, Florida, pH 7.5; Cat Island, Texas, pH 6.9 [3,20]. Climate in the maritime communities of the southeastern United States is one of mild winters with high humidity and long, hot, humid summers. The July mean temperature is about 81 degrees Fahrenheit (27 deg C). On the Atlantic coast most rainfall occurs during summer and early fall. Rainfall averages over 39 inches (1,000 mm) per year, and in some places considerably more. In Florida, Miami receives 60 inches (1,524 mm) of precipitation annually; Key West receives 38 inches (965 mm); Tortugas receives 33 inches (838 mm). There is a steady decrease in rainfall from Pensacola, Florida, west to Brownsville, Texas, where rainfall is 27 inches (680 mm) per year. October and November are the driest months on the northern and eastern Gulf coast. March is the driest month at Brownsville, Texas [19,20,23]. Soil temperature variation on seaoats sites is greatest in the surface inch of soil. In the early afternoon soil surface temperatures of 125 to 127 degrees Fahrenheit (52-53 deg C) are common in the early afternoon when air temperature is 95 to 100 degrees Fahrenheit (35-38 deg C) [20]. SUCCESSIONAL STATUS: Seaoats is a pioneer species [15]. It spreads locally through vegetative reproduction; it colonizes new areas primarily through seed dispersal [11], but seaoats plant parts can also be dispersed by ocean currents. Of 17 surveyed small islands near Key West, Florida, seaoats had colonized 14 [15]. Seaoats is also a climax species because of its high tolerance for salt spray. Succession in the salt spray community is limited primarily by the intensity of the spray, and does not show the usual climatically controlled pattern [20]. Seaoats is dominant on ocean-facing primary dunes even if the dunes are stable because it tolerates more salt spray than other species. If the shoreline is rising, however, the beach in front of the primary dunes may accrete and new dunes form in front of old ones. Then distance from the ocean to the original dunes will increase, the effect of salt spray will diminish [23], and seaoats may be replaced by other vegetation [16]. Eventually, succession to a climax forest of subtropical mixed hardwood may occur [23]. Rather than rising, most of the shoreline of the southeastern United States is subsiding. On the Gulf coast west of the Mississippi Delta to Texas, the rate of coastal retreat is 3.3 to 164 feet (1-50 m) per year. Seaoats can achieve vegetative lateral spread of 2 to 6 feet (0.6-1.8 m) per year, but this is generally not sufficient to keep pace with the high rate of subsidence. Seaoats is not dominant in this area and is reduced to a few sparse, scattered populations [11]. SEASONAL DEVELOPMENT: Seaoats growing season is May 1 to September 4 on Currituck Bank, North Carolina. The germination period of seaoats seeds there is late May to the middle of June [26]. Spikelets fall from the plant and disperse in late fall and early winter [16]. Seaoats flowers and sets fruit (combined) at the following times: Carolinas June-November [21] Florida central spring-fall [29] panhandle October-November [2] Texas April-November [18,9] General range June-September [4]


SPECIES: Uniola paniculata
FIRE ECOLOGY OR ADAPTATIONS: Seaoats reproduces vegetatively [14]. It probably sprouts from rhizomes after aerial portions are burned. FIRE REGIMES: Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes". POSTFIRE REGENERATION STRATEGY: Rhizomatous herb, rhizome in soil Ground residual colonizer (on-site, initial community) Initial-offsite colonizer (off-site, initial community)


SPECIES: Uniola paniculata
IMMEDIATE FIRE EFFECT ON PLANT: Seaoats is probably top-killed by fire. PLANT RESPONSE TO FIRE: Seaoats likely sprouts from the rhizomes after top-kill by fire. FIRE MANAGEMENT CONSIDERATIONS: Recurring fires are common to the maritime strand of the Coastal Plain of the southeastern United States [20]. Although blowouts, shifting sand, and wandering dunes are characteristic of strands, these phenomena were much accelerated in the past by grazing management practices. On some barrier islands seaoats and other dune grasses were burned off to improve forage. This gave more palatable forage for a brief part of the growing season, but it also reduced the total cover and greatly accelerated the inland movement of sand. On Smith's Island, North Carolina, what was formerly a barren area of shifting small dunes has developed substantial cover because of reduced grazing and elimination of fire [20].


SPECIES: Uniola paniculata
REFERENCES: 1. Carls, E. Glenn; Lonard, Robert I.; Fenn, Dennis B. 1991. Notes on the vegetation and flora of North Padre Island, Texas. Southwestern Naturalist. 36(1): 121-124. [14888] 2. Clewell, Andre F. 1985. Guide to the vascular plants of the Florida Panhandle. Tallahassee, FL: Florida State University Press. 605 p. [13124] 3. Davis, John H., Jr. 1943. The natural features of southern Florida, especially the vegetation, and the Everglades. Geological Bull. No. 25. Tallahassee, FL: State of Florida, Department of Conservation, Florida Geological Survey. 311 p. [17748] 4. Duncan, Wilbur H.; Duncan, Marion B. 1987. The Smithsonian guide to seaside plants of the Gulf and Atlantic Coasts from Louisiana to Massachusetts, exclusive of lower peninsular Florida. Washington, DC: Smithsonian Institution Press. 409 p. [12906] 5. Eleuterius, Lionel N. 1989. Planting configurations, propagation methods tested for dune plants (Mississippi). Restoration and Management Notes. 7(1): 41-42. [8062] 6. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905] 7. Fleming, Karen; Holler, N. R. 1988. Endangered beach mice repopulate Florida beaches. In: Highlights of natural resources management 1988. Natural Resources Report NPS-NR-89-01. Denver, CO: U.S. Department of the Interior, National Park Service: 5-6. [12051] 8. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998] 9. Gould, Frank W. 1978. Common Texas grasses. College Station, TX: Texas A&M University Press. 267 p. [5035] 10. Gould, Frank W.; Shaw, Robert B. 1983. Grass systematics. 2d ed. College Station, TX: Texas A&M University Press. 397 p. [5667] 11. Hester, Mark W.; Mendelssohn, Irving A. 1987. Seed production and germination response of four Louisiana populations of Uniola paniculata (Gramineae). American Journal of Botany. 74(7): 1093-1101. [21973] 12. Hester, Mark W.; Mendelssohn, Irving A. 1989. Water relations and growth responses of Uniola paniculata (sea oats) to soil moisture and water-table depth. Oecologia. 78(3): 289-296. [21972] 13. Hester, Mark W.; Mendelssohn, Irving A. 1990. Effects of macronutrient and micronutrient additions on phytosynthesis, growth parameters, and leaf nutrient concen. of Uniola paniculata and Panicum amarum. Botanical Gazette. 151(1): 21-29. [14435] 14. Hitchcock, A. S. 1951. Manual of the grasses of the United States. Misc. Publ. No. 200. Washington, DC: U.S. Department of Agriculture, Agricultural Research Administration. 1051 p. [2nd edition revised by Agnes Chase in two volumes. New York: Dover Publications, Inc.]. [1165] 15. Johnson, Ann F.; Barbour, Michael G. 1990. Dunes and maritime forests. In: Myers, Ronald L.; Ewel, John J., eds. Ecosystems of Florida. Orlando, FL: University of Central Florida Press: 430-480. [17394] 16. Johnson, A. Sydney; Hillestad, Hilburn O.; Shanholtzer, Sheryl Fanning; Shanholtzer, G. Frederick. 1974. An ecological survey of the coastal region of Georgia. Scientific Monograph Series No 3, NPS 116. Washington, DC: U.S. Department of the Interior, National Park Service. 233 p. [16102] 17. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. [1384] 18. Lonard, Robert I.; Judd, Frank W. 1989. Phenology of native angiosperms of South Padre Island, Texas. In: Bragg, Thomas B.; Stubbendieck, James, eds. Prairie pioneers: ecology, history and culture: Proceedings, 11th North American prairie conference; 1988 August 7-11; Lincoln, NE. Lincoln, NE: University of Nebraska: 217-222. [14049] 19. Mendelssohn, Irving A.; Hester, Mark W.; Monteferrante, Frank J.; Talbot, Fay. 1991. Experimental dune building and vegetative stabilization in a sand- deficient barrier island setting on the Louisiana coast, USA. Journal of Coastal Research. 7(1): 137-149. [17761] 20. Oosting, Henry J. 1954. Ecological processes and vegetation of the maritime strand in the southeastern United States. Botanical Review. 20: 226-262. [10730] 21. Radford, Albert E.; Ahles, Harry E.; Bell, C. Ritchie. 1968. Manual of the vascular flora of the Carolinas. Chapel Hill, NC: The University of North Carolina Press. 1183 p. [7606] 22. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. [2843] 23. Stalter, Richard; Odum, William E. 1993. Maritime communities. In: Martin, William H.; Boyce, Stephen G.; Echternacht, Arthur C., eds. Biodiversity of the southeastern United States: Lowland terrestrial communities. New York: John Wiley & Sons, Inc: 117-163. [22010] 24. Stickney, Peter F. 1989. Seral origin of species originating in northern Rocky Mountain forests. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT; RWU 4403 files. 7 p. [20090] 25. Texas Parks and Wildlife Department. 1992. Plant communities of Texas (Series level): February 1992. Austin, TX: Texas Parks and Wildlife Department, Texas Natural Heritage Program. 38 p. [20509] 26. Tyndall, R. Wayne; Teramura, Alan H.; Mulchi, Charles L.; Dougalss, Larry W. 1987. Effects of salt spray upon seedling survival, biomass, and distribution on Currituck Bank, North Carolina. Castanea. 52(2): 77-86. [22110] 27. U.S. Department of Agriculture, NRCS. 2018. PLANTS Database, [Online]. U.S. Department of Agriculture, Natural Resources Conservation Service (Producer). Available: [34262] 28. Will, M. E.; Sylvia, D. M. 1990. Interaction of rhizosphere bacteria, fertilizer, and vesicular-arbuscular mycorrhizal fungi with sea oats. Applied and Environmental Microbiology. 56(7): 2073-2079. [22876] 29. Wunderlin, Richard P. 1982. Guide to the vascular plants of central Florida. Tampa, FL: University Presses of Florida, University of South Florida. 472 p. [13125]

FEIS Home Page