The term "mangrove" may be used for a variety of tropical and subtropical plant species (in many cases not closely related to each other) that grow in highly saline coastal environments and as a consequence share many adaptations that allow them to survive and reproduce under these conditions (e.g., thick, waxy leaves to minimize water loss in their salty surroundings). Mangroves are trees or shrubs that grow with their roots partly or wholly submerged in sea water. The Red Mangrove (Rhizophora mangle) is particularly extreme in its ability to survive with its roots bathed in salt water. In Florida, Red Mangroves reach about 6 meters, but in the tropics they may grow to four times that height. The dark green leaves are shiny and broad. Reddish prop roots arch from the trunk into the water; old individuals may have aerial roots hanging from branches. Stalked yellow, waxy flowers are produced in groups of 4. The fruit is a leathery brown, conical berry about 2.5 cm long. The Red Mangrove is one of a number of mangrove species that are "viviparous", i.e., the seeds germinate while still attached to the parent. Red Mangrove seedlings (sometimes known as "sea pencils") up to 30 cm long hang from branches during much of the year. (Kaplan 1988)
Mangroves are builders. They help build up new land along the shore and are the anchors for rich and complex communities involving diverse animals, plants, fungi, and microorganisms (although plant species diversity in mangrove habitats is generally much lower than animal diversity). They serve as nurseries for many fish and invertebrates, including many that migrate along the shore or out into the ocean as adults. They filter the water and buffer the effects of hurricanes. Kaplan (1988) provides an excellent and accessible introduction to the ecology of mangroves and mangrove swamps.
Presences in the middle Atlantic Islands has been recorded for this species (Trinidade e Martim Vaz, St. Helenia, Ascension-), but this is not confirmed.
Regularity: Regularly occurring
Global Range: Found on shores of central and southern Florida including Florida Keys, Bermuda, and throughout West Indies to Trinidad and Tobago and Dutch West Indies. Also on both coasts of continental tropical America from central Mexico south to Ecuador, northwestern Peru and to Brazil (Little and Wadsworth 1964). Found in Melanesia, Polynesia, Galapagos Islands (Chudnoff 1993), Cape Verde Islands, Hawaii (Tree Talk 1994) and along the west coast of Africa (Record and Mell 1924).
Red Mangrove (Rhizophora mangle) is found in peninsular Florida, Bermuda, the West Indies, Central and South America, and Africa (Tiner 1993)
Red Mangrove is found from West Africa to the Pacific Coast of tropical America. In Africa, its latidudinal limits are not clear, but it has been recorded as far south as Angola and as far north as Mauritania. In the Americas it has a wide distribution on the Atlantic side, from about 25° N in Florida south to eastern Brazil; on the Pacific side, Red Mangrove occurs from Mexico to northern Chile, where its southern range is limited by cold, dry climate. Populations in New Caledonia, Fiji, Tonga, and Samoa are treated by some researchers as a form of R. mangle, but by others as a closely related but distinct species, R. samoensis. There has been some suggestion that R samoensis co-occurs with R. mangle in Pacific South America. (Tomlinson 1986)
Red Mangrove propagules from Florida were introduced to the southwestern part of Moloka'i (in the Hawaiian Archipelago) in 1902 to stabilize coastal mudflat erosion from pastures and sugarcane fields and for honey production. The mangrove introduction on Moloka'i was very successful, and today it composes the largest stand of mangroves in the Hawaiian Islands. The first confirmed mangrove introduction on O‘ahu occurred in 1922 when several species of Old World mangroves, possibly including Red Mangrove, were planted in He‘eia by the Hawaiian Sugar Planter’s Association. However, there is a report of a small mangrove tree growing near Honolulu as early as 1917, probably a propagule from Moloka‘i. Most of the (at least) six species of mangroves or closely associated species that have been introduced to Hawai‘i over the years have disappeared or are very limited in their distribution (Allen 1998). However, Red Mangrove has been very persistent and has successfully colonized all the main islands except Kaho‘olawe and Ni‘ihau. (Chimner et al. 2006 and references therein). This species has been introduced and become established in other far flung places as well, such as Tahiti (Zomlefer et al. 2006).
Red Mangrove (Rhizophora mangle) is a broad-leaved evergreen tropical shrub or tree that may reach 24 meters. It has conspicuous arching prop, or stilt, roots. Older bark is reddish and smooth; younger bark is grayish. Twigs are silverish to shiny dark brown. The stalked, oppositely arranged leaves (5 to 16 cm long and up to 8 cm wide) are simple, entire, and smooth, with a prominent midrib. They are leathery, dark green and shiny above and lighter green (often speckled) below. The somewhat leathery, 4-petaled flowers are pale yellowish or cream colored. They are borne on stalks (about 1 to 4 cm long) in clusters of 2 or more. The fruit is an elongate greenish capsule, about 2.5 cm before germination. The seed germinates while still on the plant, giving the fruit a curved, elongate appearance. (Tiner 1993)
In Florida, Red Mangrove (Rhizophora mangle) can be most obviously distinguished from Black Mangrove (Avicennia germinans) and White Mangrove (Laguncularia racemosa) by the fact that these latter two species have numerous (especially Black Mangrove) erect breather roots emerging from the water, as well as by the Red Mangrove's distinctive seedlings attached to the parent. Gray Mangrove (or Buttonwood, Conocarpus erectus) has alternately arranged leaves, in contrast to the opposite leaves of the Red, Black, and White Mangroves. (Petrides 1988)
An excellent resource for identifying the mangroves of Florida can be found at http://www.selby.org/
Habitat and Ecology
In Port Royal (17°56'N, 76°79'W), R. mangle grows in a dense monospecific stands, bordering all wetland water bodies. It is also present in a mixed zone between the R. mangle monospecific stands and monospecific stands of C. erectus, which is the border between the wetland and terrestrial zones (Alleng 1998).
Flowering occurs annually in mid-winter and spring within the wider Caribbean. Propagule size can be variable, shown to be larger in areas of higher rainfall (Tyagi 2003). Production of viviparous propagules is abundant and maintained on the parent tree for 3-6 months. Once dropped, propagules can subsist for extended periods afloat prior to rooting. Successful growth requires a canopy break or transport to open area to grow to maturity.
Fringing R. mangle (in association with seagrass beds) provide critical for Caribbean parotfish (Scarus guacamaia), a species listed as vulnerable on the Red Data List. This species is also associated with stabilization of sandy beaches critical for sea turtle nesting habitat, among countless other critical habitat functions.
Comments: Occurs in mangrove swamps at the mouths of large estuarine rivers and fringing ocean coast in certain places (Record and Mell 1924).
Depth range (m): 1 - 2
Depth range (m): 1 - 2
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
In the United States, Red Mangrove (Rhizophora mangle) is found in mangrove swamps, salt marshes, and fresh marshes (near the coast) of the Florida Everglades (Tiner 1993).
Red Mangrove habitats are of great importance to a wide diversity of organisms, including fish (Thayer et al. 1987; Kaplan 1988). Animal diversity in mangrove ecosystems is generally much higher than plant diversity.
Burrowing isopods, such as Phycolimnoria clarkae and Sphaeroma peruvianum, and encrusting barnacles (Balanus spp.) reduce root growth in Red Mangrove; leaves are consumed by land crabs and caterpillars, such as the larvae of the skipper Phocides pigmalion (Perry 1988: Ellison and Farnsworth 1996 and references therein).
The intertidal air-breathing gastropod Melampus coffeus is a critical component in the breakdown of mangrove leaf litter, and it forms an important link between mangrove forest productivity and estuarine food webs. Although a number of other invertebrate species act to accelerate litter breakdown in mangrove and salt-marsh systems (e.g., shredder snails, sesarmid crabs), M. coffeus belongs to a smaller group that can directly assimilate the resources in mangrove leaves. Thus, where M. coffeus is abundant, substantial portions of mangrove leaf material are converted to snail biomass and larvae. Adult snails are preyed upon by white ibis (Eudocimus albus); juvenile snails may be preyed on by Fundulus heteroclitus killifish, which may forage in the leaf litter at high tide; and larvae are exported to the estuary. (Proffitt and Devlin 2005 and references therein)
Land crabs are very important components of mangrove ecosystems. They differentially prey on seeds, propagules, and seedlings along nutrient, chemical, and physical environmental gradients. Such abiotic factors are well known to influence plant species distributions. Lindquist et al. (2009), however, argue that in mangrove ecosystems crab predation is more important than many of these environmental factors in shaping the dynamics and organization of coastal forests. These authors also found that crabs facilitate forest growth and development through such activities as excavation of burrows, creation of soil mounds, aeration of soils, removal of leaf litter into burrows, and creation of carbon-rich soil microhabitats. Crabs influence the distribution, density and size-class structure of tree populations. Given the evident importance of crabs as among the major drivers of tree recruitment (i.e., establishment of a new generation) in tropical coastal forest ecosystems, Lundquist et al. suggest that their conservation should be included in management plans for these forests. (Lundquist et al. 2009)
The dominant members of the crab fauna in mangroves belong to the families Gecarcinidae, Grapsidae, and Ocypodidae. The grapsid crabs are the primary consumers of propagules in the Indo-West Pacific region. In the eastern Pacific, Atlantic, and Caribbean, the gecarcinids (e.g. Cardisoma spp.) and Ocypodids (e.g. Ucides spp.) are more important than the grapsids. (Lindquist et al. 2009 and refrerences therein)
Lundquist et al. (2009) found that crab predation on Red Mangrove was less severe in canopy gaps than in the understory, similar to the pattern found by Sousa et al. (2003a) for predation by the stem-boring scolytid beetle Coccotrypes rhizophorae. In the study by Sousa et al. on the Caribbean coast of Panama, the authors found that the Red Mangrove's water-borne propagules establish
wherever they strand, but long-term sampling revealed that only those that do so in or near lightning-created canopy gaps survive and grow to maturity. These microsites provide better growth conditions than the does surrounding understory and, equally important, provide refuge from predation by C. rhizophorae. Sousa et al. (2003b) found that if an infestation of C. rhizophorae did
not completely girdle a Rhizophora seedling, the seedling could survive, but grew at a reduced rate.
In a study in southwestern Puerto Rico, Wier (2004) found cankers, dead branches and trunks, and as much as 32% mortality consistently associated with the fungus Cytospora rhizophorae. The presence of this fungus, an agent of the cytospora canker disease, correlated with proximity to arboreal nests of the termite Nasutitermes costalis. High incidence of this termite (40%), was detected in injured red mangroves. Wier presents circumstantial evidence that this fungus is carried and disseminated by Nasutitermes costalis, with spores that enter branch and root wounds germinating and forming canker-weakened trees that may die prematurely.
Gilbert and Sousa (2002) studied the host-associations of wood-decaying basidiomycete polypore fungi on three mangrove species (Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa) in a Panamanian mangrove forest. They note that the pattern typically observed for these fungi in diverse tropical forests is that there are a large number of rare species, with the smaller number of common species necessarily being nonspecialists due to the challenge of host rarity. In contrast, the authors found that in the tropical mangrove forest they studied, the polypore assemblage was strongly dominated by a few host-specialized species. Three fungal species, each with a strong preference for a different mangrove host species, comprised 88 percent of all fungi collected (the authors note, however, that these fungi are all reported from other hosts outside of mangrove forests as well). At least for polypore fungi within tropical mangrove forests, where host diversity is low and the abundance of individual host species is high, the restriction against host specialization typically imposed by host rarity in tropical forests may be relaxed, resulting in a polypore community dominated by a few common host-specialist species. (Gilbert and Sousa 2002)
Ecologically, tropical mangrove swamp forests share many similarities with salt marshes to the north (although mangroves are woody and salt marshes are generally dominated by grasses and other herbaceous vegetation). Both mangrove swamps and salt marshes occur at the interface of land and sea, protect the coast from storm damage (especially hurricanes), and serve as important nurseries for fish and invertebrates. Mangrove leaves are an important source of energy for marine food webs: fallen leaves are colonized by bacteria, fungi, and protozoans, which are in turn fed upon by zooplankton, which in turn are consumed by juvenile fish and larval invertebrates. (Kricher 1988)
Unlike most plants, Red Mangroves (like some other mangrove species) produce seeds that germinate while still attached to the parent. The Red Mangrove embryo grows into a seedling that may be 25-30 cm long before dropping off the tree into seawater. These elongated seedlings float for several days until the pointed end absorbs enough water to become too heavy to float and sinks. The waxy fruit end (from which the seedling sprouted) still floats, causing the seedling to bob along in the water with the pointed end pointed downward. While still in this state, which can last as long as a year, a few leaves may sprout from the upper end and roots may sprout from the lower end. If the young plant comes into contact with sediment, it will take root. This may occur even far from land, where ocean currents have piled up sand within a few centimeters of the water's surface.
In a year the plant may grow to a meter tall. Within three years it will produce many prop roots, which look like pendulous branches growing down into the water. If other mangoves have rooted nearby, a little forest may form in just a few years. The maze of prop roots slows the currents and tiny suspended particles sink to the bottom in a self-reinforcing process as muddy sand builds up. Mangrove leaves fall and become trapped among the roots, where they are broken down and decomposed by diverse small invertebrates, fungi, and bacteria. The resulting rich organic detritus mixes with the sand to form a rich, densely packed sediment. This is the first stage of a continuous transformation involving a succession of organisms that continue to modify the habitat in which they live. In Florida and the Caribbean, once sufficient sediment has built up, Black Mangrove (Avicennia germinans) becomes established alongside the Red Mangrove and on somewhat higher ground, several meters back from the water's edge, White Mangrove and Gray Mangrove form a mixed forest. Eventually this process of natural succession transforms what was once saltwater into dry land. (Kaplan 1988)
Ball (1980) provides a detailed historical analysis of the development and dynamics of "induced" mangrove forests that developed in response to salinization (by human-driven changes to local hydrology) of areas formerly supporting freshwater marshes along Biscayne Bay in North Miami, Florida, U.S.A.
Red Mangrove (Rhizophora mangle) flowers year-round, but, at least in the southeastern United States, especially in spring and summer (Tiner 1993).
Life History and Behavior
The seed, while still attached to the tree, develops a radicle which, when detached, falls like a dart and sticks upright in the mud ready to put forth leaves and roots immediately; some are carried away by tides and can thus populate newly formed mudbars and islands.
Evolution and Systematics
Aerial roots of mangroves take in air through pores (lenticels) and pass it to hypoxic roots via aerating tissue (aerenchyma).
"In well oxygenated soil, there is little difficulty in obtaining the oxygen needed for respiration. This is not so in waterlogged soils, and special aerating devices are required. In growing Rhizophora, roots diverge from the tree as much as 2 m above ground, elongate at up to 9 mm d-1, and penetrate the soil some distance away from the main stem (Figs I.3, 1.4 and 5.1 [sic]). As much as 24 per cent of the above-ground biomass of a tree may consist of aerial roots: the main trunk, as it reaches the ground, tapers into relative insignificance […] On reaching the soil surface, absorptive roots grow vertically downwards, and a secondary aerial root may loop off and penetrate the soil still further away from the main trunk […] The method of aerating the underground roots is understood best in the red mangrove Rhizophora mangle of Florida. Functionally, the aerial components can be divided structurally into more or less horizontal arches and vertical columns. These have no problems in achieving adequate gas exchange, at least at low tide. In contrast, the underground roots are in a permanently hypoxic, or even anoxic, environment. The columns have the role of supplying oxygen to the underground roots. Air passes into the column roots through numerous tiny pores, or lenticels, which are particularly abundant close to the point at which the column root enters the soil surface. It can then pass along roots through air spaces. Roots entering the soil are largely composed of aerenchyma tissue; honeycombed with air spaces which run longitudinally down the root axis (Fig. 1.5) […] The importance of lenticels for gas exchange has been demonstrated by measuring O2 and CO2 concentrations in the aerenchyma of Rhizophora roots. When the lenticels are occluded by smearing grease over the aerial potion of the root, O2 declines continuously and CO2 rises (Fig. 1.6). Control roots showed fluctuations related to tidal level (Scholander et al. 1955)." (Hogarth 1999:5-8)
Learn more about this functional adaptation.
- Hogarth, P. J. The biology of mangroves. Oxford University Press. 228 p.
Roots of red mangrove forests protect coastal shorelines by absorbing energy from waves.
Red mangroves "Protect coastal land, by absorbing the energy of storm-driven wave and wind action--creating in effect a natural breakwater that helps stop erosion, preventing a great deal of property damage and sometimes even human death." (Reef Ball Foundation 2007)
Learn more about this functional adaptation.
Reef Ball Foundation Mangrove Solutions Division. 2007. Why is a mangrove important?. Reef Ball Foundation.
Seeds of mangroves find optimal conditions by reacting to time passage and light conditions.
"All mangroves disperse their offspring by water. A distinctive feature of the majority of mangrove species is that they produce unusually large propagating structures or propagules…The long, pointed appearance of Rhizophora propagules hanging on the parent tree has led to the belief that they plummet like darts into the mud below and so immediately establish themselves…The reality is more complex. Rhizophora propagules generally float for some time before rooting themselves. Initially, floating is horizontal. Over a period of a a month or so they shift to a vertical position. This makes it more likely that the tip will drag in the mud surface and result in the propagule stranding when the tide recedes. Roots first appear after 10 days or so, and many of the propagules lose bouyancy [sic] and sink. Presumably before this has happened the propagule is not ready to establish itself as a seedling. By 40 days, virtually all propagules show root growth (Banus and Kolehmainen 1975). Most will strand in a horizontal position and erect themselves after rooting in the mud…Propagules which do not successfully root after 30 days or so may regain buoyancy and float off again in a horizontal position. They may remain viable for a year or more (Rabinowitz 1978b). Occasionally, propagules are still viable after being transported tens of kilometers inland by hurricanes…The timing of these events is affected by circumstances. In sunny conditions, virtually all floating Rhizophora propagules pivot to the vertical by 30 days and root within a further 10 days or so; about half of shaded propagules are still floating horizontally after several months. This behaviour will facilitate settling in forest clearings rather than directly under adult trees (Banus and Kolehmainen 1975)." (Hogarth 1999:24, 27-30)
Learn more about this functional adaptation.
- Hogarth, P. J. The biology of mangroves. Oxford University Press. 228 p.
Physiology and Cell Biology
Gilbert et al. (2002) studied the possible role of salt excretion by mangroves as a defense against pathogenic fungi in a mangrove forest in Panama. Although presumably evolved for other reasons, salt excretion by leaves of some mangrove species may serve as an important defense against fungal attack, reducing the vulnerability of typically high-density, monospecific forest stands to severe disease pressure. In their study, Gilbert et al. found that Black Mangrove (Avicennia germinans) suffered much less fungal leaf damage from than did White Mangrove (Laguncularia racemosa) or Red Mangrove (Rhizophora mangle). Black Mangrove leaves also supported the least fungal growth on the leaf surface, the least endophytic colonization, and the lowest fungal diversity, followed by White Mangrove and Red Mangrove.
Host specificity of leaf-colonizing fungi was greater than expected at random. The fungal assemblage found on Black Mangrove appears to be a subset of the fungi that can grow on the leaves of Red and White Mangrove. The authors suggested that the different salt tolerance mechanisms in the three mangrove species may differentially regulate fungal colonization. The mangroves differ in their salt tolerance mechanisms such that Black Mangrove (which excretes salt through leaf glands) has the highest salinity of residual rain water on leaves, White Mangrove (which accumulates salt in the leaves) has the greatest bulk salt concentration, and Rhizophora (which excludes salt at the roots) has little salt associated with leaves. The high salt concentrations associated with leaves of Black and White Mangrove, but not the low salinity of Red Mangrove, were sufficient to inhibit the germination of many fungi associated with mangrove forests. The authors suggest that efficient defenses against pathogens may be especially important in natural communities, such as mangrove forests, where host diversity is low and the density of individual hosts is high – ideal conditions for diseases to have strong effects on plant populations.
Mangrove forests are unusual among tropical forests for their low tree species diversity and associated high population density of
individual species. Mangrove species are unusual in their ability to grow in flooded, saline soils and for the array of mechanisms they have evolved to tolerate high salt concentrations. The work by Gilbert et al. suggests that some mangrove species may also be unusual in their escape from strong disease pressures, even when growing at high densities, through the inhibitory effects of
high foliar (leaf) salt concentration on fungal infection. (Gilbert et al. 2002)
Molecular Biology and Genetics
Takayama et al. (2008) developed microsatellite markers useful for studying population structure of Rhizophora mangle and related species.
Barcode data: Rhizophora mangle
Statistics of barcoding coverage: Rhizophora mangle
Public Records: 3
Specimens with Barcodes: 8
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Reasons: Found on shores of central and southern Florida including Florida Keys, Bermuda, and throughout West Indies to Trinidad and Tobago and Dutch West Indies. Also on both coasts of continental tropical America from central Mexico south to Ecuador, northwestern Peru and to Brazil (Little and Wadsworth 1964). Found in Melanesia, Polynesia, Galapagos Islands (Chudnoff 1993), Cape Verde Islands, Hawaii (Tree Talk 1994) and along the west coast of Africa (Record and Mell 1924). In parts of northern South America there are very extensive mangrove swamps at the mouths of all the great rivers and fringing the coast in certain places. The accessible stands in Venezuela have been seriously depleted and the forests around Lake Maracaibo now produce only small-sized poles. The forests of Porto Cabello have been practically destroyed and are now areas of low scrubby growth. On the deeper soils, muddy banks, and islands of the Orinoco delta, however, there are pure stands of red mangrove still in virgin condition (Record and Mell 1924).
Mangroves in general, and Red Mangrove in particular, are highly vulnerable to coastal development, pollution, and other human impacts (Kaplan 1988). In many parts of the world, mangroves are collected for firewood.
Specific population information exists for this species in the following areas:
At the mouthouth of Lostman's River in Everglades National Park, FL, U.S., 611 individuals were counted over six transects totaling 0.26 ha (McCoy et al. 1996).
In Laguna de Celestun, Yucatan, Mexico, combined data for A. germinans, R. mangle and L. racemosa show basal area ranges from 21 square meters/ha to 36 square meters/ha (Herrera-Silveira and Ramirez-Ramirez 1998).
In Parque Nacional Morrocoy, Venezuela, data show 68% R. mangle, 29% L. racemosa, 8% A. germinans, 1% unidentified total tree density, and 348 trees/0.1 ha (Bone et al. 1998).
All mangrove ecosystems occur within mean sea level and high tidal elevations, and have distinct species zonations that are controlled by the elevation of the substrate relative to mean sea level. This is because of associated variation in frequency of elevation, salinity and wave action (Duke et al. 1998). With rise in sea-level, the habitat requirements of each species will be disrupted, and species zones will suffer mortality at their present locations and re-establish at higher elevations in areas that were previously landward zones (Ellison 2005). If sea-level rise is a continued trend over this century, then there will be continued mortality and re-establishment of species zones. However, species that are easily dispersed and fast growing/fast producing will cope better than those which are slower growing and slower to reproduce.
In addition, mangrove area is declining globally due to a number of localized threats. The main threat is habitat destruction and removal of mangrove areas. Reasons for removal include cleared for shrimp farms, agriculture, fish ponds, rice production and salt pans, and for the development of urban and industrial areas, road construction, coconut plantations, ports, airports, and tourist resorts. Other threats include pollution from sewage effluents, solid wastes, siltation, oil, and agricultural and urban runoff. Climate change is also thought to be a threat, particularly at the edges of a species range. Natural threats include cyclones, hurricane and tsunamis.
Comments: Has been heavily exploited for timber (Record and Mell 1924).
Collectively, considering Red Mangrove together with other mangrove species, at least 35% of the world’s mangrove forests have been lost in the past few decades as a consequence of human activities. This loss directly affects ecosystem services such as providing habitat for fishes, prawns, and crabs. Additionally, degradation of the remaining mangrove habitats results in loss of ecological functionality, putting millions of coastal people in jeopardy. Among the threats to mangroves are aquaculture and coastal development, altered hydrology, sea level rise, and nutrient overenrichment. (Feller et. al 2010 and references therein)
Relevance to Humans and Ecosystems
Root: Used to treat diarrhea in NW Guyana. Stem: A bark decoction is used to treat frequent dysentery, diarrhea, micturition and bladder diseases in Guyana. Bark is febrifuge, astringent, rich in tannin, used in a decoction in French Guiana for haemorrhages, and in gargles to remedy angina. Bark used to treat diarrhea in NW Guyana.
Uses: Building materials/timber, Fuelwood
Comments: The timber is (has been) employed for rafters, scantling, beams, joists, braces, knees and ribs of boats, and miscellaneous construction, and also for posts, piling, railway ties, charcoal and fuel. The chief use is (has been) for tannin extracted from the bark which is also used for dyeing and medicine (Record and Mell 1924). The tree serves as a timber species in Costa Rica (Alvarez 1991). Other general timber applications of this species are cooperage, railroad crossties, rafters, fencing, tannery, charcoal (Santos 1987), turnery, life boats and mining timbers (Tree Talk 1994).
Extracting tannic acid (which stains the water in a mangrove habitat a transparent brown) from Red Mangrove bark for use in tanning was at one time a major industry in the Florida Keys (Kaplan 1988).
Rhizophora mangle, known as the red mangrove, is distributed in estuarine ecosystems throughout the tropics. Its viviparous "seeds," in actuality called propagules, become fully mature plants before dropping off the parent tree. These are dispersed by water until eventually embedding in the shallows.
Rhizophora mangle grows on aerial prop roots, which arch above the water level, giving stands of this tree the characteristic "mangrove" appearance. It is a valuable plant in Florida, Louisiana, and Texas coastal ecosystems. In its native habitat it is threatened by invasive species such as the Brazilian pepper tree (Schinus terebinthifolius). The red mangrove itself is considered an invasive species in some locations, such as Hawaii, where it forms dense, monospecific thickets. R. mangle thickets, however, provide nesting and hunting habitat for a diverse array of organisms, including fish, birds, and crocodiles.
Red mangroves are found in subtropical and tropical areas in both hemispheres, extending to approximately 28°N to S latitude. They thrive on coastlines in brackish water and in swampy salt marshes. Because they are well adapted to salt water, they thrive where many other plants fail and create their own ecosystems, the mangals. Red mangroves are often found near white mangroves (Laguncularia racemosa), black mangroves (Avicennia germinans), and buttonwood (Conocarpus erectus). Through stabilisation of their surroundings, mangroves create a community for other plants and animals (such as the mangrove crab). Though rooted in soil, mangrove roots are often submerged in water for several hours or on a permanent basis. The roots are usually sunk in a sand or clay base, which allows for some protection from the waves.
Red mangroves are easily distinguishable through their unique prop roots system and viviparous seeds. The prop roots of a red mangrove suspend it over the water, thereby giving it extra support and protection. They also help the tree to combat hypoxia by allowing it a direct intake of oxygen through its root structure.
A mangrove can reach up to 80 feet (24 m) in height in ideal conditions; however, it is commonly found at a more modest 20 feet (6.1 m). Its bark is thick and a grey-brown color. Mangrove leaves are 1–2 inches (2.5–5.1 cm) wide and 3–5 inches (7.6–12.7 cm) broad, with smooth margins and an ellipse shape. They are a darker shade of green on the tops than on the bottoms. The tree produces pale pink flowers in the spring.
As a viviparous plant, R. mangle creates a propagule that is in reality a living tree. Though resembling an elongated seed pod, the fully-grown propagule on the mangrove is capable of rooting and producing a new tree. The trees are hermaphrodites, capable of self pollination or wind pollination. The tree undergoes no dormant stage as a seed, but rather progresses to a live plant before leaving its parent tree. A mangrove propagule may float in brackish water for over a year before rooting.
Propagules growing before dropping from the parent plant. (BioBay, Vieques)
- Allen, J.A., 1998. Mangroves as Alien Species: The Case of Hawaii. Global Ecology and Biogeographical Letters 7:61-71
- "Rhizophora". Encyclopedia of Life. Retrieved 28 November 2012.
French Guiana: paletuvier rouge. Guyana Akawaio: mangero. Guyana Carib: konopo. Guyana Warrau: bu. Guyana Arawak: kakutiro, kakutiru. Guyana Creole: mangrove, red mangrove. Surinam: mangrove. Surinam Sranan: mangro.
This is the plant referred to in Ref: 7 as Rhizophora gymnorrhiza L.