Leaf and flower detail of the red mangrove, Rhizophora mangle.  Photo courtesy of C. Feller, Smithsonian Environmental Research Center.

      
Propagules of Rhizophora mangle.  When ripe, these young seedlings detach from the parent tree and float in the estuary until a suitable substratum is contacted.  Photo courtesy of C. Feller, Smithsonian Environmental Research Center.

Species Name: 
Rhizophora mangle L.

Common Name:
Red Mangrove, mangrove, American mangrove

Species Description:
Mangrove swamps dominate much of the world's tropical and sub-tropical coastlines, and have a similar distribution pattern as coral reefs. There are approximately 35 species of true mangroves and another 60 or more species of mangrove associates. Most species occur throughout the Indo-Pacific region, with 3 commonly occurring in the Americas.

Rhizophora mangle, the red mangrove, is a subtropical/tropical tree which colonizes coastlines and brackish water habitats below the 20 degree isotherm in both the northern and southern hemispheres. Red mangrove trees dominate the Atlantic and Gulf coasts of the United States to about 28 degrees north latitude, after which a zone of transition to salt marshes occurs.

Red mangroves generally are found closest to the water's edge and are distinguished easily from other mangroves by their prominent prop roots which extend into the water from higher up on the stem of the plant. Red mangroves have leaves which are somewhat larger and shinier than those of other mangroves.  They are further distinguished by their fruits, or propagules, which are long and pencil-shaped. While these may resemble seed pods, they are actually embryonic root structures.

II.  HABITAT AND DISTRIBUTION 

Regional Occurrence:
Rhizophora mangle occurs worldwide in coastal and estuarine areas of the tropics and subtropics to about 28° in both the northern and southern hemispheres. 

IRL Distribution:
In the Indian River Lagoon, red mangroves are common landscape features to approximately 28° North, around the vicinity of Merritt Island. North of this location is the transition zone where mangrove forests gradually give way to salt marshes. Frost stress north of the transition zone prevents red mangroves from becoming established.

III. LIFE HISTORY AND POPULATION BIOLOGY

Age, Size, Lifespan:
Little is known regarding typical age to maturation in mangroves in south Florida, though it has been hypothesized that maturation age for mangroves in Florida is in some way linked to the periodicity of hurricanes.

Abundance:
Red mangroves are generally the dominant species of mangrove at or immediately adjacent to the water line, though they may often occur with black mangroves and white mangroves.

Dispersal:
Propagules of the red mangrove detach from the parent tree upon ripening and may float in salt water for approximately one year without rooting.

Reproduction:
Rhizophora mangle flowers are thought to be self pollinated or wind pollinated. Following fertilization, mangrove propagules undergo continuous development from flower to germinated seedling while still attached to the parent plant, with no dormant or seed phase, thus exhibiting vivipary. The seedlings, or propagules, eventually fall from the parent plant and are able, in the absence of suitable substrata, to float for extended periods (over a year) in salt water without rooting.

IV.  PHYSICAL TOLERANCES

Temperature:
The geographic range of R. mangle generally matches the 20 °C isotherm in both the northern and southern hemispheres, and is similar to the range of coral reefs. Frost stress beyond 28° north and south latitudes prevents red mangroves from becoming well established. However, when subjected to cold stress, populations of red mangroves show differences in survival rate and amount of damage done per plant based on their geographic points of origin.

Salinity:
As facultative halophytes, mangroves have the ability to thrive in waterlogged soils which may have salinities ranging from 0 - 90 ppt. Mangroves exhibit several different types of mechanisms for coping with highly saline conditions. Rhizophora mangle excludes the salt in seawater at the root-substratum interface. The black mangrove (Avicennia germinans) and the white mangrove (Laguncularia racemosa) are able to take up seawater through their roots, but they excrete excess salt through pores, or salt glands, located on the surface of leaves.

Other Physical Tolerances: 
Mangroves can experience reducing conditions to at least -200 mV. One of the most visibly obvious adaptations to anoxia are root adaptations. R. mangle utilizes prop roots which grow downwards from the stem of the plant, rather than relying on roots growing upwards from the substrate. Lenticels, or pores, in the aerial roots are presumed to be the path through which oxygen is supplied to the underground root system. Fine lateral rootlets are able to accumulate in the substratum, and produce most of the underlying peat on which mangrove swamps are built.

Adaptations to extremes in pH have not been examined in the red mangrove, however, pH values between 5.3 and 7.8 have been reported.

V.  COMMUNITY ECOLOGY

Trophic Mode:
Mangrove forests typically show a wide range of productivity, depending on factors such as hydrological regimes, nutrient supply, etc., and are considered to be vital sources of organic matter for estuarine systems.

Competitors:
Ball (1980) suggested that competition among the 3 mangrove species may be partially responsible for the zonation observed in many mangrove areas. Direct consumers of mangrove propagules in Florida include the spotted mangrove crab (Goniosis cruentata), the mangrove land crab (Ucides cordatus), the coffee bean snail (Malampus coffeus) and the ladder horn snail (Cerithidea scalariformis). Consumers of mangrove leaves include the mangrove crab (Aratus pisonii), the spotted mangrove crab (G. cruentata), the blue land crab (Cardisoma guanhumi), and various types of insects. Wood boring isopods feed upon and damage prop roots.

Habitat:
Red mangrove propagules may float for upwards of a year without taking root. They generally take root upon coming to rest on a suitable substrate area consisting of sand, silt, mud or clay which offers some protection from waves. Propagules may root even while completely submerged; and mature trees, depending on type, tend not to be sensitive to hydroperiod; they may remain submerged anywhere from several hours to nearly permanently without showing adverse effects.

Associated Species:
Mangroves form intertidal forests in which red mangrove prop roots, black mangrove pneumatophores, and their associated peat banks serve as the dominant intertidal substrata for other members of the mangrove community. Black mangroves (Avicennia germinans) and white mangroves (Laguncularia racemosa) are usually found in association with red mangroves. Segregation of the 3 species does occur, however; with red mangroves typically occupying the lowest intertidal position. Black and white mangroves occur at slightly higher tidal elevations.

VI. SPECIAL STATUS

Special Status:
Habitat structure

Benefit in the IRL:
Mangrove forest ecosystems are vital as sources of energy and provide nursery habitat for juvenile fish, and invertebrates. They also provide roosting and nesting habitat for wading birds. Additionally, they are a source for timber production and are important as buffers in decreasing storm impacts along coastlines.

Economic Importance:
Because of their vital role in providing nursery habitat for juvenile fish, many of which are commercially or recreationally important, mangroves contribute to the continuing success of Florida's tourism and fishing industries. 

VII. BIBLIOGRAPHY

Ball, M.C. 1980. Patterns of Secondary Succession in a Mangrove Forest of
      Southern Florida. Oecologia 44:226-235.

Chale, F. 1996. Litter Production in an Avicennia germinans (L.) Stearn Forest
      in Guyana, South America. Hydrobiologia 330:47-53.

Carlton, J. 1974. An Ecological Survey of Selected Mangrove Communities in
      Florida. Master of Arts Thesis. Department of Biology in the University of
      South Florida.

Day, J., W. Conner, et al. 1987. The Productivity and Composition of Mangrove
      Forests, Laguna De Terminos, Mexico. Aquatic Botany 27:267-284.

D'Croz, L., J. Rosario, et al. 1989. Degradation of Red Mangrove (Rhizophora
      mangle L.) Leaves in the Bay of Panama. Rev. Biol. Trop. 37(1):101-104.

Ellison, A., and E. Farnsworth. 1996. Spatial and Temporal Variability in Growth
      of Rhizophora mangle Saplings on Coral Cays: Links with Variation in
      Insolation, Herbivory, and Local Sedimentation Rate. Journal of Ecology
      84:717-731.

Everitt, J.H., and F.W. Judd. 1989. Using Remote Sensing Techniques to
      Distinguish and Monitor Black Mangrove (Avicennia germinans). Journal of
      Coastal Research 5(4):737-745.

Ewa-Oboho, I.O., and N.J. Abby-Kalio. 1993. Seasonal Variation and
      Community Structure of Epibenthic Algae on the Roots of the Mangrove
      Rhizophora mangle at a Shallow Tropical Estuary. Tropical Ecology
      34(2):160-172.

Feller, I.C. 1995. Effects of Nutrient Enrichment on Growth and Herbivory of
      Dwarf Red Mangrove (Rhizophora mangle). Ecological Monographs
      65(4):477-505.

Gonzalez, C.D., E. Rivas, et al. 1995. Factores Que Afectan La Adaptacion
      Postsiembra De Plantulas De Rhizophora mangle L. 1773 En Las Islas Del
      Rosario, Caribe Colombiano. Boletin Ecotropica 28:16-32.

Hernandez-Alcantara, P., and V. Solis-Weiss. 1995. Algunas Comunidades
      Macrobenticas Associadas Al Manglar (Rhizophora mangle) en Laguna de
      Terminos, Golfo de Mexico. Rev. Biol. Trop. 43(1-3):117-129.

Johnston, S.A. 1983. Preliminary Report on Avicennia Germinans Communities
      Located on Ile De Chien, (Dog Island), Franklin County, Florida. Tropical
      Ecology 24(1):13-18.

Lin, G., and L.L. Sternberg. 1992. Comparative Study of Water Uptake and
      Photosynthetic Gas Exchange Between Scrub and Fringe Red Mangroves,
      Rhizophora mangle L. Oecologia 90:399-403.

Lin, G., and L. Sternberg. 1993. Effects of Salinity Fluctuation on Photosynthetic
      Gas Exchange and Plant Growth of the Red Mangrove (Rhizophora mangle
      L.). Journal of Experimental Botany 44(258):9-16.

Lin, G., and L. Sternberg. 1995. Variation in Propagule Mass and its Effect on
      Carbon Assimilation and Seedling Growth of Red Mangrove (Rhizophora
      mangle) in Florida, USA. Journal of Tropical Ecology 11:109-119.

Lopez-Portillo, J., and E. Ezcurra. 1985. Litter Fall of Avicennia germinans L.
     in a One-Year Cycle in a Mudflat at the Laguna de Mecoacan, Tabasco,
      Mexico. Biotropica 17(3):186-190.

McCoy, E.D., H.R. Mushinsky, et al. 1996. Mangrove Damage Caused by
      Hurricane Andrew on the Southwestern Coast of Florida. Bulletin of Marine
      Science 59(1):1-8.

McKee, K.L., and I.A. Mendelssohn. 1987. Root Metabolism in the Black
      Mangrove (Avicennia Germinans (L.): Response to Hypoxia. Environmental
      and Experimental Botany 27(2):147-156.

McKee, K.L. 1995. Seedling Recruitment Patterns in a Belizean Mangrove
      Forest: Effects of Establishment Ability and Physico-Chemical Factors.
     Oecologia 101:448-460.

McMillan, C., and C.L. Sherrod. 1986. The Chilling Tolerance of Black
      Mangrove, Avicennia Germinans, From the Gulf of Mexico Coast of Texas,
      Louisiana and Florida. Contributions in Marine Science 29:9-16.

Mullin, S.J. 1995. Estuarine Fish Populations Among Red Mangrove Prop Roots
      of Small Overwash Islands. Wetlands 15(4):324-329.

Patterson, C.S., I.A. Mendelssohn, et al. 1993. Growth and Survival of
      Avicennia germinans Seedlings in a Mangal/Salt Marsh Community in
      Louisiana, U.S.A. Journal of Coastal Research 9(3):801-810.

Pulver, T.R. 1976. Transplant Techniques for Sapling Mangrove Trees,
      Rhizophora mangle, Laguncularia racemosa and Avicennia germinans,
      in Florida. Florida Department of Natural Resources, Marine Research
      Laboratory, Number 22, 14 Pages.

Rey, J.R. 1994. Effects of Neighbors on Growth and Mortality of Mangrove
      Seedlings in Florida, U.S.A. Wetlands 14(4):308-315.

Ribi, G. 1981. Does the Wood Boring Isopod Sphaeroma terebrans Benefit
      Red Mangroves (Rhizophora mangle)? Bulletin of Marine Science
      31(4):925-928.

Ribi, G. 1982. Differential Colonization of Roots of Rhizophora mangle by the
      Wood Boring Isopod Sphaeroma terebrans as a Mechanism to Increase
       Root Density. Marine Ecology 3(1):13-19.

Stephens, W.M. 1962. Tree that Makes Land. Sea Frontiers 8(4):219-230.

Rivadeneyra, R.I. 1989. Ecology of the Epibiosis on the Submerged Roots of
      Rhizophora mangle in Bahia De La Ascension, Quintana Roo, Mexico.
      Ciencias Marinas 15(1):1-20.

Savage, T. 1972. Florida Mangroves: A Review. Florida Department of Natural
      Resources, Marine Research Laboratory, St. Petersburg, Florida. Leaflet
      Series: Volume VII - Marine Plants. Part 2 (Vascular Plants) No.1, 15
      Pages.

Schmalzer, P.A. 1995. Biodiversity of Saline and Brackish Marshes of the Indian
      River Lagoon: Historic and Current Patterns. Bulletin of Marine Science
      57(1):37-48.

Smith, S.M., and S.C. Snedaker. 1995a. Salinity Responses in Two Populations
      of Viviparous Rhizophora mangle L. Seedlings. Biotropica 27(4):435-440.

Smith, S.M., and S.C. Snedaker. 1995b. Developmental Responses of
      Established Red Mangrove, Rhizophora mangle L. Seedlings to Relative
      Levels of Photosynthetically Active and Ultraviolet Radiation. Florida Scientist
      58:55-60.

Snedaker, S.C., J.A. Jimenez, et al. 1981. Anomalous Aerial Roots in Avicennia
      Germinans (L.) L. in Florida and Costa Rica. Bulletin of Marine Science
      31(2):467-470.

Snedaker, S.C., M.S. Brown, et al. 1992. Recovery of a Mixed-Species
      Mangrove Forest in South Florida Following Canopy Removal. Journal of
      Coastal Research 8(4):919-925.

Soto, R. 1988. Geometry, Biomass Allocation and Leaf Life-Span of Avicennia
      germinans L.(Avicenniacae) Along a Salinity Gradient in Salinas,
      Puntarenas, Costa Rica. Rev. Biol. Trop. 36(2A):309-323.

Tattar, T.A., E.J. Klekowski, et al. 1994. Dieback and Mortality in Red
      Mangrove, Rhizophora Mangle L. in Southwest Puerto Rico. Aboricultural
      Journal 18:419-429.

Thibodeau, F.R., and N.H. Nickerson. 1986. Differential Oxidation of Mangrove
      Substrate by Avicennia Germinans and Rhizophora Mangle. Amer. J. Bot.
      73(4):512-516.

Vaughan, T.W. 1910. The Geologic Work of Mangroves in Southern Florida.
      Smithsonian Miscellaneous Collections 52(UML 14,101):461-464.

Report by:  K. Hill, Smithsonian Marine Station
with thanks to G. Raulerson, LSU
Submit additional information, photos or comments to:
irl_webmaster@si.edu
Page last updated: July 25,  2001