Title: Mangroves of the Virgin Islands
Full Citation
Permanent Link: http://ufdc.ufl.edu/CA01300974/00001
 Material Information
Title: Mangroves of the Virgin Islands
Physical Description: Book
Language: English
Creator: U.S. Virgin Islands
Publisher: U.S. Virgin Islands
Place of Publication: U.S. Virgin Islands
Publication Date: 2005
 Record Information
Bibliographic ID: CA01300974
Volume ID: VID00001
Source Institution: University of the Virgin Islands
Holding Location: University of the Virgin Islands
Rights Management: All rights reserved by the source institution and holding location.


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Mangroves of the Virgin Islands

Mangroves are trees that are adapted to live in areas that
are often flooded by water, places called wetlands. In the Virgin
Islands, there are three types of mangroves; red, black and white,
that live in saltwater and brackish water wetlands. While our
mangroves are not related to each other, they all have developed
mechanisms for surviving in water and ridding themselves of excess
salt. Mangroves have different tolerances for the amount of salt
and water they can live in. The red mangrove is the most salt and
water tolerant of the three species. Black mangroves are less salt
tolerant and white mangroves are even less so.
All mangrove roots trap sediment washed from our hillsides
during rainfall. Mangroves become most useful in areas where the
land has been cleared. By trapping sediment, mangroves keep our
water clear and protect our reefs and seagrass beds. Mangroves are
called "landformers" since the soil they trap causes the shoreline
to grow seaward over time. As the shoreline expands from, the
accumulation of trapped dirt, the mangroves continue to grow
towards the water. Terrestrial plants colonize the land behind the
mangroves and provide habitat for many species.
Red mangroves have adapted to living in salt water by
elevating themselves above the water on proproots and preventing
the uptake of salt by blocking it at the root. Red mangroves
produce a propagule which hangs from the parent tree until mature
and then drops into the water. If the water is shallow enough, the
propagule may stick in the mud like a dart and grow there. If the
water is too deep, the propagule may float many miles from the
parent. The root end is heavier and hangs down. Eventually, it
drifts into shallow water and takes root in the muddy or sandy
bottom. Red mangroves have long prop roots that reach down into
the water. These roots serve as a nursery area for most
coral reef fish and many invertebrates. Decaying leaves and twigs
in the water under the mangrove trees provide a rich source of
organic nutrients for other nearby marine ecosystems such as
seagrasses and coral reefs.


Black mangroves live landward of the red mangroves in
saturated soils where the trees "breathe" using roots called
pneumatophores. These specialized roots project up from the
surface of the mud, forming a forest of little fingers. These
projections not only act as "snorkels" for the roots to breathe,
they trap sediment and chemicals from water running off the land
into the sea. The leaves of the black mangroves are long and
narrow and covered with salt crystals underneath that it has
excreted out through the leaves. It is through these mechanisms
that the black mangrove has adapted to living in salty,
waterlogged soils and is able to rid itself of excess salt. The
black mangrove produces seeds which float and may travel long
distances before washing ashore and growing into a tree.

'Black Mangrove (Avicennia germinans)

White mangroves are usually found more inland than the other
species. They prefer drier soils or areas with more fresh water
input such as coastal ponds having less connection to the sea.
White mangroves sometimes produce pneumatophores like the black
mangrove. They also have adapted to excrete excess salt through
two small pores on the stem supporting the leaf or actually
through the leaf surface, where it can be seen as crystals on the
leaves. White mangroves also produce seeds that float and can
disperse great distances.
Mangroves grow in protected bays which are ideal for marinas
and boat facilities. Over the past 50 years, we have lost 40 to 50
percent of our mangroves to these and other activities. During
impending storms, tying your boat to mangroves is allowed, but as
a long term mooring method this can damage the bark and kill the
tree. Chafing gear should always be used when tying to mangroves
to protect the bark from abrasion. Storms may also kill mangroves

by stripping their leaves off and abrading the bark. Mangroves,
already surviving under stressful conditions (waterlogged soils
and osmotic problems with salt excretion), generally do
not recover from major storm damage and die.

White Mangrove (Laguncularia racemosa)

Mangroves are very important in many ways. Numerous wildlife
such as humming birds, pigeons, herons and iguanas either nest,
rest or feed in mangroves over water where they are safe from
predators. They protect coastlines from wave erosion and reduce
the amount of sediment reaching the ocean. They serve as valuable
nursery habitats for many juvenile reef fish that inhabit our
coral reefs.
Mangroves are protected by law in the U.S.Virgin Islands. Any
cutting of mangroves should be reported to Dept. of Planning &
Natural Resources.

St. Thomas Mangroves

1. Perseverance Bay Pond
2. Flamingo Bay Pond
3. Careening Cove Fringing
4. Mangrove Lagoon Fringing, manglars* and
5. Benner Bay Pond
6. Great Bay Pond Ritz Carlton
7. Vessup Bay Fringing
8. Cabrita Point Pond
9. Red Hook Pond
10. Sapphire Pond/Marina
11. Smith Bay Pond
12. Sugar Bay Pond (Remnants)
13. Water Bay "Iguana" Pond
14. Mandahl Pond
15. Magens Bay Basin forest
16. Hull Bay Basin forest

* This term applies to small islets made up entirely of
mangroves with no solid land.

Note: This does not show the locations of all mangroves on St.
Thomas. The locations shown on this map are the most obvious or
easily accessible.



k -

St. John Mangroves


Cruz Bay Fringing
Frank Bay and Enighed Ponds
Great Cruz Bay Back beach basin
Chocolate Hole Pond
Fish Bay Fringing, basin forest and ponds
Reef Bay Back beach basin
Great Lameshur Basin forest
Mandahl Pond
Kiddel Bay Pond
Salt Pond
Friis Bay Pond
Coral Bay Basin forest, pond and fringin
Hurricane Hole Fringing
East End Pond
Haulover Bay (North) Fringing (small)
Mary's Creek Fringing
Francis Bay Pond
Big Maho Bay Back beach basin
Cinnamon Bay Back beach basin
Trunk Bay Back beach basin

Note: This does not show the locations of all mangroves on St.
John. The locations shown on this map are the most obvious or
easily accessible.


St. Croix Mangroves

1. Rust-Op-Twist Pond
2. Salt River Fringing, basin forest
3. Altona Lagoon Fringing
4. Southgate Pond
5. Coakley Bay Pond
6. Buck Island Pond
7. Robin Bay Pond
8. Great Pond
9. Halfpenny Bay Pond
10. Billy French Ponds
11. Ruth Island Fringing
12. Alucroix Channel Fringing
13. Krause Lagoon Fringing
14. Fairplain Gut Fringing
15. Manning Bay Fringing
16. West End Saltpond

Note: This does not show the locations of all mangroves on St.
Croix. The locations shown on this map are the most obvious or
easily accessible.


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