Biogeography

Belizean coast mangroves

Content Cover Image

Mangroves at the mouth of the Monkey River, southern Belize. Source: C.Michael Hogan

The Belizean coast mangroves ecoregion (part of the larger Mesoamerican Gulf-Caribbean mangroves ecoregion) extends along the Caribbean Coast from Guatemala, encompassing the mangrove habitat along the shores of the Bahía de Annatique; this ecoregion continues along the Belizean coast up to the border with Mexico. This ecoregion is threatened by expanding tourism on the coastal areas of Belize along with growth in indigenous human populations. The presence of mangroves on the coastal fringe becomes more prevalent along the more southwestern reaches of the Belizean coastline. The ecoregion is denoted by the World Wildlife Fund as NT1405.

This mangrove association not only provides protection against coastal erosion and hence habitat stabilitity, but also supplies nesting and resting sites for many bird species; additionally the root zone offers a quiet protective zone for a multiplicity of juvenile marine organisms. Disturbance regimes do not include appreciable risk of frost, but are comprised chiefly of hurricanes and lightning strikes.

Geography and climate

Mesoamerican Gulf-Caribbean mangroves which include Belizean coast mangroves. WWF.

The Belizean coast mangroves ecoregion includes the mainland coastal fringe, but is separate from the distinct ecoregion known as the Belizean reef mangroves which are separated from the mainland. This ecoregion includes the Monterrico Reserve in Guatemala, the estuarine reaches of the Monkey River and the Placencia Peninsula. The ecoregion includes the Burdon Canal Nature Reserve in Belize City, which reach contains mangrove forests and provides habitat for a gamut of avian species and threatened crocodiles. The Shipstern Nature Reserve includes mangrove shorelines as well as a saline lagoon system and hardwood forests. The total areal extent of the Belizean coast mangroves is approximately 2800 square kilometres.

The tropical climate exhibits a rainy season from May to February and mean annual rainfall ranges from 1400 millimetres (mm) in the north to in excess of  4000 mm in the south. Spring tide amplitudes range between twenty and thirty centimetres. Although this is a partially protected area from high wave action, due to coral reefs farther in the sea, there are occasional severe tropical storms and hurricanes that make landfall here, from origination further to the east and south in the Caribbean Basin.

Flora

caption Mangrove shoreline across from Placencia Peninsula. @ C.Michael Hogan

Chief mangrove tree species found in this ecoregion are White Mangrove (Laguncularia racemosa), Red Mangrove (Rhizophora mangle), Black Mangrove (Avicennia germinans); the Button Mangrove (Conocarpus erectus) is a related tree associate. Red mangrove tends to occupy the more seaward niches, while Black mangrove tends to occupy the more upland niches. Other plant associates occurring in this ecoregion are Dragonsblood Tree (Pterocarpus officinalis), Guiana-chestnut (Pachira aquatica) and Golden Leatherfern (Acrostichum aureum).

Fauna

caption Heron in mangrove wetland, Monkey River mouth. @ C.Michael Hogan In addition to hydrological stabilisation leading to overall permanence of the shallow sea bottom, the Belizean coastal zone mangrove roots and seagrass blades provides abundant nutrients and shelter for a gamut of juvenile marine organisms. A notable marine mammal found in the shallow seas offshore is the threatened West Indian Manatee (Trichecus manatus), who subsists on the rich Turtle Grass (Thalassia hemprichii) stands found on the shallow sea floor.

Wood borers are generally more damaging to the mangroves than leaf herbivores. The most damaging leaf herbivores to the mangrove foliage are Lepidoptera larvae. Other prominent herbivores present in the ecoregion include the gasteropod Littorina angulifera and the Mangrove Tree Crab, Aratus pisonii.

Many avian species from further north winter in the Belizean coast mangroves, which boast availability of freshwater inflow during the dry season. Example bird species within or visiting this ecoregion include the Yucatan Parrot (Amazona xantholora), , Yucatan Jay (Cyanocorax yucatanicus), Gray Catbird (Dumetella carolinensis) and the Great Kiskadee (Pitangus sulphuratus).

Upland fauna of the ecoregion include Lowland Paca (Agouti paca), Coatimundi (Nasua narica), and Baird’s Tapir (Tapirus bairdii). Aquatic species within the ecoregion include Morelet's Crocodile (Crocodylus moreletti), Green Turtle (Chelonia mydas), Hawksbill Sea Turtle (Eretmochelys imbricata), Loggerhead Sea Turtle (Caretta caretta), and Kemp’s Ridley (Lepidochelys kempi).

Black Howler Monkeys (Alouatta caraya) occur in the riverine mangroves in the Sarstoon-Temash National Park within the ecoregion.  The Mantled Howler Monkey (Alouatta palliata) can be observed along the mangrove fringes of the Monkey River mouth and other portions of this mangrove ecoregion.

Ecology

Pygmy or scrub forests are found in certain reaches of the Belizean mangroves. In these associations individual plants seldom surpass a height of 150 centimetres, except in circumstances where the mangroves grow on depressions filled with mangrove peat. Many of the shrub-trees are over forty years old. In these pygmy mangrove areas, nutrients appear to be limiting factors, although high salinity and high calcareousSoils which are high in limestone content substrates may be instrumental.

Chief disturbance factors are due to hurricanes and lightning strikes, both capable of causing substantial mangrove treefall. In many cases a pronounced gap is formed by lightning strikes, but such forest gaps actually engender higher sapling regrowth, due to elevated sunlight levels and slightly diminished salinity in the gaps.

Aquatic facultatve mutualism occurs in this ecoregion between certain invertebrates and mangrove tree species. For example, prop-roots of Rhizophora mangel support a sponge fouling community; moveover, apparently the mangrove trees and the fouling sponges share nitrogen and carbon resources, resulting in enhanced growth and production of the two mutualistic partners. Thus the presence of sponges actually constitutes symbiosis, since it is also known that sponges along with ascidians actually inhibit the colonisation of boring isopods from the aerial prop-roots, and hence enhance growth of the mangroves.

Conservation status

The ecoregion is experiencing ongoing damage to the mangrove systems driven by an expanding indigenous human population as well as increases in tourism. Specific articulations of these phenomenona include the obliteration of the mangrove habitat at Belize City and urban coastal zone encroachment along the Placencia Peninsula, where hotel and condominium development are proceeding at a rapid pace. In addition, disposal of solid waste debris near indigenous human settlements are polluting mangrove habitat as well as interspersed backshore areas.

References

  • Daniel M.Alongi. 2009. The energetics of mangrove forests. 216 pages
  • Les Beletsky and David Beadle. 2005. Belize & Northern Guatemala. Interlink Books. 477 pages
  • Luiz Drude de Lacerda. 2002. Mangrove ecosystems: function and management. Springer. 292 pages
  • Alistar I.Robertson and Daniel M.Alongi. 1991. Tropical mangrove ecosystems. American geophysical Union. 329 pages
  • P.Saenger. 2002. Mangrove ecology, silviculture, and conservation. Springer. 360 pages
  • World Wildlife Fund. 2001. Belizean coast mangroves. NT1405
Glossary

Citation

Hogan, C. (2013). Belizean coast mangroves. Retrieved from http://www.eoearth.org/view/article/51cbf0427896bb431f6a0f26

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