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International Journal of Marine Science 2014, Vol.4, No.58, 1-7
http://ijms.biopublisher.ca
2
Materials and Methods
A survey has been made during 2012-2014 on the true
mangroves and their associates along 56 estuaries of
Tamil Nadu (Fig. 2). The coastline was divided into
five different groups such west coast of Tamil Nadu (3
estuaries), Gulf of Mannar (10 estuaries), Palk Bay
(13 estuaries), South Coromandel coast (13 estuaries)
and North Coromandel coast (16 estuaries). The
mangroves and associate vegetation were identified
following the standard references of
10,18,22-25
.
Nomenclatures of the identified species were checked
with the International Plant Names Index (IPNI).
Species not recorded shows minus (-) symbol, present
shows one plus (+) symbol, it means species available
1-3 sites; co-abundant shows two plus (++) symbol, it
means species recorded 4-6 sites; abundant shows
three plus (+++) symbol, it means species found 7-9
sites; dominant shows four plus (++++) symbol, it
means species observed above 9 sites.
Results
A total of 39 species of mangroves and mangrove
associate species were reported in 56 estuaries. The
highest number of mangroves and associates (31)
was observed in the North Coromandel coast,
followed by Gulf of Mannar (23), South Coromandel
coast (20), west coast of Tamil Nadu (19) and Palk
Bay region (17).
A total of 16 mangroves belonging to 11 genera and 9
families were recorded along the Tamil Nadu coast.
Fourteen mangrove species were observed in the
North Coromandel coast, six species from South
Coromandel coast, six species from the Gulf of
Mannar, five species from West coast of Tamil Nadu,
two species from the Palk Bay region. Nine of the 16
mangrove species belonged to two families: six in
Rhizophoraceae and three in Avicenniaceae.
Avicennia
marina
was the most dominant mangrove species in
North Coromandel coast and co-abundant species in
Gulf of Mannar, Palk Bay and South Coromandel
coast.
Bruguiera gymnorrhiza
was only reported in the
Ariyankuppam and Thengathittu estuary of northern
part of Coramandel coast and
Avicennia alba
was
reported only in Palayakayal estuary of Gulf of
Mannar coast. Among the mangrove plants,
Rhizophora
annamalayana
,
Bruguiera cylindrica
,
B. gymnorrhiza
,
Ceriops decandra, Lumnitzera racemosa
and associate
species
Derris trifoliata, Xylocarpus mekongenesis
,
Thespesia populnea
,
Heritiera littoralis
were noted as
species specific to the North Coromandel coast (Table 2).
Mangrove associates (23 species) belonging to 21
genera and 17 families were recorded. The North
Coromandel region and Gulf of Mannar were reported
with more number of species (17 species), followed
by Palk Bay (15 species), west coast of Tamil Nadu
(14 species) and southern part of Tamil Nadu (14
species). Number of species were greatest in the in
Chenopodiaceae family (5 species), Malvaceae family
(3 species), and Convolvulaceae family (2 species). A
terrestrial plant species,
Calotropis gigantea
was
dominant in North Coromandel coast, abundant in
South Coromandel coast and co-abundant in Palk Bay
and Gulf of Mannar. Two mangrove associates
Pongamia pinnata
and
Ipomoea pes-caprae
were
dominant in North Coromandel coast were observed
as dominant species. Three associate species in
Pongamia pinnata
and
Calotropis gigantea
in South
Coromandel coast and
Citrullus colocynthis
in North
Coromandel coast were found as abundant - species
(Table 3 & Figure 1).
Mangrove associate plants were mostly found in all
the sampling stations, but mangrove plants were noted
only in a few stations. A mangrove species (
Avicennia
marina
) and four associates (
Thespesia populnea
,
Sesuvium portulacastrum
,
Calotropis gigantea
and
Citrullus colocynthis
) were reported in all five groups
of study areas. Three mangrove species (
Avicennia
officinalis
,
Rhizophora apiculata
and
R. mucronata
)
and nine associates (
Catharanthus roses, Pongamia
pinnata
,
Suaeda maritima, S. monoica
,
Salicornia
brachiata
,
Clerodendrum inerme
,
Ipomoea pes-caprae
,
Cressa cretica
,
Spinifex littoreus, Casuarina
equisetifolia
) were present in four groups of study
areas (Table 2 & 3).
Mangroves and its associates were more in Vellar (23
species), Coleroon (17 species), Manakkudy (14
species), Sethukarai (12 species), Punnaikayal (11
species) and Palayakayal (11 species). Two stations
(Kallimedu, Arichandra nadhi) mangrove and its
associates were totally absent. Less number of
mangrove and its associates were reported in Nandalar
(1 species), Thengapattinam (3 species), Thiruchendur
(3 species), Valinokkam (3 species), Sundra Pandia
Pattinam (3 species), Thiruchendur (3 species), Pattankadu