Mangroves are the important salt tolerant vegetation having more ecological and economical significances. In comparison to that of eastern coastal part, the western coastal region of Peninsular India comprises less area of mangroves. Therefore, establishing new mangroves in suitable habitats in this region is more essential to maintain the ecological processes in coastal landscape. To select the suitable mangrove species for newer areas of Kerala coast, a preliminary study on ecology was carried out in two natural mangrove vegetation at Ayiramthengu and Mandrothruthu, Kollam district. The study revealed that out of 34 (Ayiramthengu) and 24 (Mandrothruthu) species present, a sizable number of eight and six species respectively were true mangroves and adapted more prominently in their respective site indicated by higher Importance Value Index (IVI) and Relative Value of Importance (RVI) obtained by them. Therefore, these species are suggested for new formations of mangrove vegetation in the coastal regions of Kerala.

1. Article Citation:
Sekaran S, Nisha Raj S, Arun S and Paulsamy S
Floristic constitution and certain ecological characters of two selected natural
mangrove vegetation in Kollam district, Kerala.
Journal of Research in Biology (2015) 5(5): 1763-1768
JournalofResearchinBiology
Floristic constitution and certain ecological characters of two selected
natural mangrove vegetation in Kollam district, Kerala.
Keywords:
Mangrove vegetation, Kollam district, Kerala.
ABSTRACT:
Mangroves are the important salt tolerant vegetation having more
ecological and economical significances. In comparison to that of eastern coastal part,
the western coastal region of Peninsular India comprises less area of mangroves.
Therefore, establishing new mangroves in suitable habitats in this region is more
essential to maintain the ecological processes in coastal landscape. To select the
suitable mangrove species for newer areas of Kerala coast, a preliminary study on
ecology was carried out in two natural mangrove vegetation at Ayiramthengu and
Mandrothruthu, Kollam district. The study revealed that out of 34 (Ayiramthengu) and
24 (Mandrothruthu) species present, a sizable number of eight and six species
respectively were true mangroves and adapted more prominently in their respective
site indicated by higher Importance Value Index (IVI) and Relative Value of Importance
(RVI) obtained by them. Therefore, these species are suggested for new formations of
mangrove vegetation in the coastal regions of Kerala.
1763-1768 | JRB | 2015 | Vol 5 | No 5
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www.jresearchbiology.com
Journal of Research in Biology
An International
Scientific Research Journal
Authors:
Sekaran S1
,
Nisha Raj S2
,
Arun S1
and
Paulsamy S3
Institution:
1.Department of Botany,
Sree Narayana College,
Kollam-691 001, Kerala,
India.
2. PG Department of
Biotechnology, SAS, SNDP
Yogam College,
Konni- 689691,
Kerala, India.
3. Department of Botany,
Kongunadu Arts and
Science College,
Coimbatore – 641 029,
Tamil Nadu, India.
Corresponding author:
Sekaran S
Email Id:
Web Address:
http://jresearchbiology.com/
documents/RA0506.pdf
Dates:
Received: 07 Jan. 2015 Accepted: 07 Feb. 2015 Published: 30 June 2015
Journal of Research in Biology
An International Scientific Research Journal
ORIGINAL RESEARCH
ISSN No: Print: 2231 –6280; Online: 2231- 6299

2. INTRODUCTION
Mangroves are the interesting and characteristic
community in the shallow waters of tropical and
subtropical sea. They are the rich of productive
community but extremely sensitive and fragile (Odum,
1959). They protect the coastal line from heavy cyclones,
tidal thrusts, tsunami etc. (Saini et al., 2012; Sandilyan,
2013). Therefore, establishing mangroves in suitable
places of coastal line for the countries like India is more
essential to protect the landscape. To achieve this goal,
the species richness along with their perpetuation level
by knowing their ecological attributes is the basic
requisite to select the species for introduction in coastal
area. Despite the taxonomical works, no major study on
ecology has been done in the western coastal part of
Kerala for mangroves. To address this lacuna, the present
study was carried out to select the well established
species on the basis of ecological characters.
MATERIALS AND METHODS
Study area
The mangrove vegetation in two areas viz.,
Ayiramthengu and Mandrothruthu located in Kollam
district of Kerala were selected for the present study. The
former vegetation is situated in the coastal area and
spreads over an area of about 2.5ha and the later one is in
the backwater area of Kollam district, which covers an
area of about 1.5ha.
Methods
A one hectare plot was established in each study
area and then it was divided into 100 equal subsets each
with the size of 100m2
. The sampling was made during
the month of April 2015 in both vegetations for the
quantitative ecological characters, (frequency and
abundance) of constituent species as per the methods of
Cottom and Curtis (1956). Quantitative ecological
attributes viz., density, basal area and Importance Value
Index (IVI), Relative Value of Importance (RVI) were
determined using standard methodology (Cintron and
Schaeffer-Novelli, 1984).
RESULTS AND DISCUSSION
In the vegetation of Ayiramthengu, a total
number of 34 species were enlisted which includes eight
true mangrove species and 26 mangrove associate
species. The frequency percentage was widely varied
between 20 and 100 across the species encountered
(Table 1). The plant species like Acrostichum aureum,
Bruguiera cylindrica, Cleome viscosa, Clerodendrum
inerme, Cyperus distans, Excoecaria agallocha,
Lumnitzera racemosa and Rhizophora mucronata
showed higher frequency percentage of 100 in the
community at the time of sampling. On the other hand,
the three species viz., Avicennia officinalis, Eupatorium
odoratum and Sonneratia caseolaris were exhibited
lower frequency value of less than 20 only. Density was
much varied between the species. Some species of higher
densities in the community were Cyperus distans (9.2
individuals/m2
), Rhizophora mucronata (8.2 individuals/
m2
) and Desmodium triflorum (7.0 indivuals/ m2
). On the
other hand, the species, Sonneratia caseolaris showed
lower density of less than 0.50 individuals/m2
in this
vegetation.
The mangrove species, Rhizophora mucronata
registered higher basal cover (5875796mm2
/100m2
)
followed by the other species Avicennia officinalis
(3313376mm2
/100m2
) Excoecaria agallocha
(3312102mm2
/100m2
) and Bruguiera cylindrica
(2384713mm2
/100m2
) in the community of
Ayiramthengu. The associated species, Desmodium
triflorum recorded lowest basal area of less than
223mm2
/100m2
. The relative values of frequency,
density and dominance were also varied widely among
the species. Based on the importance value index, the
species like Avicennia officinalis, Rhizophora
mucronata, Bruguiera cylindrica and Excoecaria
agallocha were regarded as species of more ecological
Sekaran et al., 2015
1764 Journal of Research in Biology (2015) 5(5): 1763-1768

3. importance. On the other hand, the spices viz.,
Eupatorium odoratum, Andrographis echioides,
Desmodium triflorum, Eclipta alba, Euphorbia
geniculata, Hyptis capitata and Ipomoea biloba were
considered as species of poor ecological importance as
they secured lower IVI value.
In Mundrothuruth vegetation, altogether 24
species (6 true mangroves and 18 mangrove associates)
were enlisted. Among them, the two species, Acanthus
ilicifolius and Acrostichum aureum were recorded higher
frequency percentage (100%) followed by another
mangrove species, Excoecaria agallocha and two
associated non-mangrove species viz., Euphorbia hirta
and Hyptis suaveolens exhibited 80% frequency (Table
Journal of Research in Biology (2015) 5(5): 1763-1768 1765
Sekaran et al., 2015
Sl.
No. Species
Fre-
quency
(%)
Density
(individu
als /m2
)
Abun-
dance
Basal
cover
(mm2
/10
0m2
)
Relative
frequency
(%)
Relative
density
(%)
Relative
domi-
nance
(%)
IVI
1 Acalypha indica 60 2.6 4.33 2070 2.78 2.25 0.01 5.04
2 Acanthus ilicifolius 40 5.6 14.00 71337.6 1.85 4.84 0.41 7.10
3 Acrostichum aureum 100 3.4 3.40 389809 4.63 2.94 2.26 9.82
4 Aegiceras corniculata 80 4.8 6.00 749044.6 3.70 4.15 4.34 12.19
5 Aerva lanata 60 3.0 5.00 597.2 2.78 2.59 0.00 5.37
6 Andrographi sechioides 40 1.0 2.50 796.2 1.85 0.86 0.00 2.72
7 Avicennia officinalis 20 3.6 18.00 3313376 0.93 3.11 19.18 23.22
8 Boerhavia diffusa 80 5.2 6.50 37261.2 3.70 4.49 0.22 8.41
9 Bruguiera cylindrica 100 5.2 5.20 2384713 4.63 4.49 13.81 22.93
10 Cleome viscosa 100 5.2 5.20 16560.6 4.63 4.49 0.10 9.22
11 Clerodendrum inerme 100 2.8 2.80 222930 4.63 2.42 1.29 8.34
12 Crotalaria striata 40 3.2 8.00 10191 1.85 2.76 0.06 4.67
13 Crotalaria verrucosa 60 2.0 3.33 6369.4 2.78 1.73 0.04 4.54
14 Croton hirtus 60 1.8 3.00 1433.2 2.78 1.55 0.01 4.34
15 Cyperus distans 100 9.2 9.20 1831.2 4.63 7.94 0.01 12.58
16 Desmodium triflorum 60 7.0 11.67 223 2.78 6.04 0.00 8.82
17 Eclipta alba 80 4.8 6.00 15286.6 3.70 4.15 0.09 7.94
18 Eupatorium odoratum 20 0.8 4.00 10191 0.93 0.69 0.06 1.68
19 Euphorbia geniculata 40 1.2 3.00 5971.4 1.85 1.04 0.03 2.92
Table 1. Frequency, density, abundance and basal cover with their relative values and importance value
index (IVI) of species in the mangrove forest of Ayiramthengu during the month of August, 2014
20 Euphorbia hirta 60 2.2 3.67 437.8 2.78 1.90 0.00 4.68
21 Excoecaria agallocha 100 2.6 2.60 3312102 4.63 2.25 19.18 26.05
22 Hyptis capitata 40 0.8 2.00 5732.4 1.85 0.69 0.03 2.58
23 Hyptis suaveolens 40 1.8 4.50 5732.4 1.85 1.55 0.03 3.44
24 Ipomoea biloba 40 1.0 2.50 4976.2 1.85 0.86 0.03 2.74
25 Leucas diffusa 80 3.8 4.75 6807.4 3.70 3.28 0.04 7.02
26 Lippia nodiflora 80 4.6 5.75 3662.4 3.70 3.97 0.02 7.70
27 Lumnitzera racemosa 100 5.4 5.40 429936.4 4.63 4.66 2.49 11.78
28 Mimosa pudica 40 1.4 3.50 2508 1.85 1.21 0.01 3.08
29 Passiflora foetida 40 0.6 1.50 1910.8 1.85 0.52 0.01 2.38
30 Rhizophora mucronata 100 8.2 8.20 5875796 4.63 7.08 34.02 45.73
31 Scoparia dulcis 80 4.8 6.00 8598.8 3.70 4.15 0.05 7.90
32 Sida alnifolia 60 2.0 3.33 3582.8 2.78 1.73 0.02 4.53
33 Sonneratia caseolaris 20 0.4 2.00 368152.8 0.93 0.35 2.13 3.40
34 Tridax procumbens 40 3.8 9.50 1936.4 1.85 3.28 0.01 5.14

4. 2). The species like Aristolochia indica, Bruguiera
cylindrica, Crotalaria striata and Lumnitzera racemosa
were showed restricted distribution due to their lower
frequency values.
The species, Acanthus ilicifolius registered
highest density of 56 individuals/m2
followed by
Excoecaria agallocha with 9.8 individuals/m2
. On the
other hand, some species like Bruguiera cylindrica,
Crotalaria striata, Ipomoea biloba and Passiflora
foetida were present with lower density of less than 1
individuals/m2
. In general, true mangrove speices
contributed higher density in the community than the
other non- mangrove plants. The species, Excoecaria
agallocha (12484074mm2
/100m2
), Rhizophora
mucronata (1003185mm2
/100m2
), and Acanthus
ilicifolius (35669.2mm2
/100m2
) have contributed higher
basal cover to the community (12484074, 1003185 and
713384mm2
/100m2
respectively) than that of other
associated species in this study on mangrove formation.
The relative value of frequency, density and
dominance were also varied widely between the species.
On ecological point of view, the secured value of IVI and
hence the total ecological importance of the species like
Acanthus ilicifolius, Excoecaria agallocha, Acrostichum
aureum, Avicennia officinalis and Rhizophora mucronata
Sekaran et al., 2015
1766 Journal of Research in Biology (2015) 5(5): 1763-1768
Table 2. Frequency, density, abundance and basal cover with their relative values and importance value
index (IVI) of species in the mangrove forest of Mundrothuruth during the month of August, 2014.
Sl.
No. Species
Fre-
quency
(%)
Density
(individ
uals /m2
)
Abun-
dance
Basal cover
(mm2
/100m2
)
Relative
fre-
quency
(%)
Relative
density
(%)
Relative
domi-
nance (%)
IVI
1. Acanthus ilicifolius 100 56.0 56.00 713384 8.20 53.74 4.04 65.98
2. Acrostichum aureum 100 7.6 7.60 871340 8.20 7.29 4.94 20.43
3. Andrographis
echioides
40 1.6 4.00 1273.6 3.28 1.54 0.01 4.82
4. Aristolochia indica 20 1.0 5.00 1791 1.64 0.96 0.01 2.61
5. Avicennia officinalis 60 2.2 3.67 2024840 4.92 2.11 11.48 18.51
6. Boerhavia diffusa 60 1.6 2.67 11465.6 4.92 1.54 0.06 6.52
7. Bruguiera cylindrica 20 0.4 2.00 183439.6 1.64 0.38 1.04 3.06
8. Cleome viscosa 40 1.8 4.50 5733 3.28 1.73 0.03 5.04
9. Clerodendrum inerme 40 1.4 3.50 111465.2 3.28 1.34 0.63 5.25
10. Crotalaria striata 20 0.6 3.00 1911 1.64 0.58 0.01 2.23
11. Desmodiumtriflorum 40 3.4 8.50 108.8 3.28 3.26 0.00 6.54
12. Eclipta alba 60 1.8 3.00 5733 4.92 1.73 0.03 6.68
13. Eupatoriu modoratum 60 1.6 2.67 20382.4 4.92 1.54 0.12 6.57
14. Euphorbia hirta 80 2.0 2.50 398 6.56 1.92 0.00 8.48
15. Excoecaria agallocha 80 9.8 12.25 12484074 6.56 9.40 70.76 86.73
16. Hyptis suaveolens 80 2.0 2.50 6370 6.56 1.92 0.04 8.51
17. Ipomoea biloba 40 0.8 2.00 3980.8 3.28 0.77 0.02 4.07
18. Lentana camera 60 1.2 2.00 54025.2 4.92 1.15 0.31 6.38
19. Lumnitzera racemosa 20 1.0 5.00 79618 1.64 0.96 0.45 3.05
20 Mimosa pudica 40 1.6 4.00 2865.6 3.28 1.54 0.02 4.83
21. Passiflora foetida 40 0.6 1.50 1911 3.28 0.58 0.01 3.87
22. Rhizophora mucronata 40 1.4 3.50 1003185 3.28 1.34 5.69 10.31
23. Scoparia dulcis 40 1.4 3.50 2507.4 3.28 1.34 0.01 4.64
24. Wattakaka bolubilis 40 1.4 3.50 50036 3.28 1.34 0.28 4.91

5. were significant as their IVI value are greater than the
other species.
In Ayiramthengu mangrove vegetations, four
true mangrove species viz., Rhizophora mucronata,
Excoecaria agallocha, Avicennia officinalis and
Bruguiera cylindrical were determined to have major
functional role as they secured higher value of relative
importance (RVI) (15.24, 8.66, 7.74 and 7.64%
respectively) (Figure 1). Similarly, in Mundrothuruth the
four true mangrove species viz., Excoecaria agallocha,
Acanthus ilicifolius, Acrostichum aureum and Avicennia
officinalis obtained higher RVI value of 28.91, 21.99,
6.81 and 6.17% respectively (Figure 2) and hence played
major role in community metabolism than the remaining
species. It may indicate that these site-specific species
were occupying higher ecological niches according to
their adaptability in the respective community.
Therefore, to establish new formations of mangrove
vegetation in coastal areas of Kollam district of Kerala
state, the above mentioned species of higher RVI values
may be considered. The other associates can be expected
to invade in such formations in course of time during
community development.
CONCLUSION
The establishment of mangrove vegetation by
constituting the important true mangrove species namely,
Rhizophora mucronata, Excoecaria agallocha,
Avicennia officinalis, Bruguiera cylindrical and
Journal of Research in Biology (2015) 5(5): 1763-1768 1767
Sekaran et al., 2015
Figure 1. Pie chart showing the contribution of
relative value of importance (RVI) by the
predominant species in the Ayiramthengu
mangrove vegetation.
Figure 2. Pie chart showing the contribution of
relative value of importance (RVI) the predominant
species in the Mandrothruthu mangrove vegetation.
Site 1. Ayiramthengu Site 2. Mandrothruth

6. Acrostichum aureum in all possible places of the coastal
part of Kollam district of Kerala is suggested to protect
this landscape very effectively.
ACKNOWLEDGEMENT
The Authors are thankful to the UGC Bangalore
for funding the Minor Research Project on “ Diversity
and Conservation Strategies on Mangrove Ecosystem
with special reference to Marshy Back waters of
Southern Kerala, Western Ghats” Vide ref No. No.F.
MRP/12th
plan/14-15/KLKE057,dated 10th
December
2014.
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1768 Journal of Research in Biology (2015) 5(5): 1763-1768
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