Download Briefing on mangroves2 - Ministry of Environment, Lands and

Ministry of Environment, Lands and Agriculture Development
ENVIRONMENT AND CONSERVATION DIVISION
PO. Box 234, Bikenibeu, Tarawa, Republic of Kiribati
Phone: (686) 28000/28593 Fax: (686) 28334
Briefing on Mangroves in Kiribati
Background
The mangrove habitat is a distinct
ecosystem that is of critical importance to
the people of Kiribati. Mangrove forests
are composed of trees, shrubs and ferns,
which live half way between the land and
the sea (inter-tidal zone). Mangroves
include approximately 20 families and
approximately 65 species worldwide.
These trees have special adaptations that
allow them to grow in soft, salty and
oxygen-deficient soils, which most other
plants cannot do. Mangrove swamps are
known to be common in most islands of
Kiribati, where these represent ‘natural
monuments’ that depict undisturbed
indigenous vegetation types, unlike most
of the land habitats that have been heavily
modified by human activities in Kiribati.
coastlines, often in conjunction with coral
reefs. Asia contains most of the world’s
mangroves with 46%, followed by
America with 35% and Africa with 17%
(MAP 1990).
Distribution of mangroves
Four different species are native to the
islands of Kiribati and these are:
Mangroves are found along tropical and
subtropical coastlines throughout the
world. They occur worldwide between the
latitudes of 30 degrees north and 38
degrees south.
At the international level, mangroves once
covered ¾ of the world’s tropical
Worldwide about 50% of the mangrove
resource has been destroyed due to overharvesting and conversion of mangrove
forests to shrimp farms and other uses.
At the national level, there are about 268
hectares of mangroves in the Gilbert
Islands. There are 166 hectares of
mangroves in Butaritari, 57 hectares in
Tarawa, 21 hectares in Maiana and 14
hectares in Aranuka. Tarawa has lost some
70% of its mangroves since the 1940s and
only 57 hectares now remains.
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Te tongo- red mangrove (Rhizophora
stylosa)
Te nikabubuti- white mangrove
(Sonneratia alba)
Te tongo buangi- oriental mangrove
(Bruguiera gymnorhiza) and
Te aitoa (Lumnitzera littorea)
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Mangroves are considered as priceless
resource that needs some form of
protection. Butaritari hosts the largest
mangrove wetlands in the Gilbert Group
that also represents Kiribati’s most diverse
mangrove forest. For instance, red
mangrove is the only species that present
in Tarawa, Maiana and Aranuka. Other
studies have indicated that ‘te aitoa’ is
existing in Tarawa. In contrast, Butaritari
has mixtures of all the four mangrove
species indicated above.
Ecological Importance of Mangroves
The mangrove ecosystem contributes
significantly to the productivity of tropical
shallow water regions. Mangrove forests
have important roles that are not readily
seen.
Mangroves are highly specialized
organisms, which constitute the most
productive of inter-tidal regions of the
world that are regularly flooded with seawater. Mangrove forests provide habitats
to many birds and aquatic marine life. The
submerged roots and trunks and aerial
forest provide a sheltered habitat for a
diverse array of marine life that also
include mosquitoes and are part of the
food chain. In summary, the root systems
of such unique trees provide ideal
breeding, nursery and feeding shelter for a
diverse range of marine aquatic lives. The
leaves fall into the water where they
supply food to small organisms, which in
turn are eaten by fish.
Mangroves are also important in
protecting and building up shorelines,
hence important in preventing beach
erosion and people’s property along
coastal areas. They also act as a buffer
zone against upland run-off during heavy
rains. That is, they help filter out landbased pollutants (run-offs), hence help to
protect reefs and fisheries from damaging
sediments during periods of heavy rainfall.
Other uses of Mangroves
Mangroves are of critical importance for
many reasons. Culturally, mangroves have
been a source of dyeing materials,
traditional medicine, magic and sorcery
and local timber. They provide habitats to
many important food species (e.g. crabs,
etc) that have been part of the local diet
for many generations.
Threats to Mangrove Forest Resources
Despite all these importance, mangroves
are also a resource in danger. The many
benefits provided by mangroves are under
threat from coastal infrastructure
development. For instance, mangroves
have been lost to land reclamation,
construction of fishponds and causeway
construction between previously separated
islets (particularly on the capital island of
Kiribati- South Tarawa, where
infrastructure developments are
concentrated). Recently, with increasing
population living on the capital island,
people have started to clear the remaining
thick mangrove forest to create passage
for their boat for easier access to lagoon,
while many others have begun to dump
rubbish in mangrove forest areas.
Destruction of mangroves in Kiribati
could mean not only less fish to eat but
also possibly reduced national income
from the sale of fishing rights and loss of
other ecological, environmental, social and
cultural benefits associated.
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