Ecological assessment of two sandy beaches along the Kerala coast, south west coast of India: perspective to pollution
V Anu Pavithran* and S Bijoy Nandan
Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, India
Submission: October 20, 2016`; Published: November 30, 2016
*Corresponding author: V Anu Pavithran, Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Kochi - 682 016, Kerala, India, Email:email@example.com
How to cite this article: V Anu Pavithran, S Bijoy N. Ecological assessment of two sandy beaches along the Kerala coast, south west coast of India: perspective to pollution.. Ocean & fish Open Access J. 2016; 1(2): 555560. DOI: 10.19080/OFOAJ.2016.01.555560
The distinct nature of the two shores (Fort Cochin and Dharmadam) of south west coast of India has the potential to evaluate the ecological function and processes. This study observed two different sandy beaches; Fort Cochin and Dharmadam and examined the faunal community structure and anthropological influences. From the entire study, it was uncovered that the shorelines chosen showed disparity in their shoreline profiles and faunal composition. Anthropological invasions and natural processes lead Fort Cochin beach to the threat of obliteration. The Dharmadam beach retained a pristine appearance; however, the temporal evaluation of beach fauna and biotic indices confirmed the occurrence of disturbed community. Impacts of anthropological activities were disclosed in the study and for which various statistical tools and biotic index like AMBI (AZTI’s Marine Biotic Index) were applied so that the ecological status of the system could be explored.
AMBI being a biotic index, which derives ecological quality status based on diverse soft bottom macro-fauna as indicators, revealed the proliferation of opportunistic species or r selected species in both beaches, which has an adverse influence on the ecosystem. The application of Caswell neutral model (It is a comparison of Shannon Wiener diversity (H’) with expected diversity) also revealed that the predicted diversity value being larger than that of actual diversity in certain seasons, indicating the dominance of organisms there. Both the statistical tools pointed out that the beaches are in the trail of destruction and disturbances, except in some selected stations. An impulsive conservation program should be necessitated to upkeep those pristine beach ecosystems.
Keywords: Sandy Beaches; Ecological Comparison; Morphology; Macrofauna; Human impacts
Abbreviations: AMBI: AZTI’s Marine Biotic Index; HTM: High Tide Mark; LTM: Low Tide Mark; TDS : Total Dissolved Solids; APHA: American Public Health Association; ANOSIM: Analysis of Similarity; MPA: Marine Protected Areas
Dark green coconut trees and loaded white sand embrace the beauty of the beaches of Kerala. Beaches of Kerala are extent along the 560-km Arabian Sea coastline. In the northern parts of Kerala, particularly in Kannur (Dharmadam beach is in Kannur district of Kerala), the outcrops ascend beyond the shore from the periphery of the beaches . Kerala coasts hold cliffs, rocky outcrops, estuaries etc and mostly the beaches of Kerala are composed of sand (When compared to other sediment types, sandy sediments are widespread on beaches) with different grain size in conjunction with broken shells of molluscs. Some of the beaches in northern part of Kerala, mainly Dharmadam beach has been identified as crescent shaped pocket beaches (Beaches have crescent shape, mainly due to waves bending) .
Kerala coastal ecosystem is tremendously stressed due to high population density and land encroachment, reclamation for urbanization, farming and other various activities add to it. Ecology of Kerala beaches are rather unrepresented and unexplored, hence awareness of beach ecology will facilitate us in proper management and protection of coastal areas. The coastline of Kerala consists of open, sandy straight or barrier type beaches , sandy beaches being the largest coastal ecosystem on earth, covering 70% of all continental margins . Beaches are of immense social and cultural significance to humans as prime recreational assets globally rather than any other kind of shoreline, beaches interrelate to people .
Sandy beaches mostly are short of biological structure,
are physically organized environments, and prop up little insitu
primary production; their food webs for that reason rely
profoundly on imports from marine sources . Present study
investigated the anthropogenic invasions on different beaches
and how they affected the community structure of those
ecosystems. The assessment of benthic quality of the selected
beaches was done with AMBI, which classifies macrofauna into
five ecological groups based on the organism’s stress sensitivity.
Present study used AMBI index as ecological status marker by
using macro invertebrates as indicators.
Fort Cochin (Cochin, Kerala) and Dharmadam (Kannur,
Kerala) beaches were preferred for the study, being stressed and
pristine respectively and also with ample samples, these beaches
were obvious choice; in addition these beaches are placed
around 279 km apart. Fort Cochin beach (Sampling site 1) (Long
760 15’ 27”E, Lat. 900 57’58”N) is an open beach with continuous
surf action, situated close to the bar mouth (0.25km south). It
has an extensive berm with gently sloping nature and has fairly
coarse sand.10-12m of beach from high tide mark (HTM) to low
tide mark (LTM) will be exposed at low tide time. Dharmadam
beach (Long. 750 27’ 23”E, Lat. 110 46’35”N) is also an exposed
beach with mixed type of sediment composition; rocky and
sandy (Figure 1). It is a long clean beach and the characteristics
of the beach sand are fine sand with darker in color and adhering
with scattered laterite rock formations. 15-30m of beach from
high (HTM) to low (LTM) will be exposed at low tide time. In
each beach two stations were selected at a distance of 500m.
Eighteen months of continuous monthly sampling and
collections were done during low tide time and it was monitored
from 2009 August to January 2011. Predicted tide tables were
used for concluding low tide period. Long shore currents were
measured by releasing a plastic bottle top into the water and
determining the time for it to travel one meter. Three consecutive
readings were taken . Number of waves and Angle of approach
of waves have been measured by visual observation and by using
magnet respectively . Quantitative sampling methods were used for the sampling process. Transect was taken and lined
across the width of the beach, generally 10- 30m transect was
taken at both the beaches. In Fort Cochin beach the exposed area
of the beach at low tide time was 10-12m and in Dharmadam it
Along this transect, quadrate of 25 x 25 cm (0.625m2) were
placed at regular intervals by using stratified random sampling
method. Four quadrates were placed along the transect in
each station. Sediments up to 15cm within the quadrate were
collected and sieved through the 0.5mm mesh sieve (500μ). The
organisms obtained after sieving were transferred to a plastic
bottle and preserved in diluted 5% buffered formalin with
filtered sea water . The fixed specimens were stained with 1%
Rose Bengal  for further identification. The epifauna of the
rocky areas of beaches were collected by hand picking and also
by using chisels. For quantitative measurements, quadrates were
placed on rocky surface and the organisms within the quadrates
were collected and preserved. Visual observations of organisms
like birds of the beaches were also done for getting the trophic
status of those beaches.
Water quality parameters from both the beaches were
analyzed, by collecting water samples. Twelve water quality
parameters, most influential to residing macrofauna of the
selected shorelines were analyzed for the study. Temperature of
water samples was measured by using centigrade thermometer
(range = 0-500C +0.10C) and pH by Systronics pH meter (No.335,
accuracy+ 0.01). Salinity, turbidity and TDS (Total Dissolved
Solids) were measured with Systronics water analyzer (Model
no.317) and conductivity was measured by using digital
potentiometer (Model no.318). Carbon dioxide and nutrients
were measured according to standard procedures from APHA
 and dissolved oxygen by Winkler’s Method . Arrays
of Statistical analysis were done for the better explanation of
sample data and the software program PRIMER Vs. 6.0 was used
for this .
Statistical analysis like Caswell neutral model and ANOSIM
(Analysis of Similarity) analysis were done. Caswell neutral
model (V statistics) is a comparison of Shannon diversity (H’)
with expected diversity conditional on the observed number
of species S and individuals N under some model rules for the
community, which are ‘ecologically neutral’. V (N.D.) is calculated
by subtracting E [H’] from H’ and dividing by the standard error
of H’. ANOSIM is used to measure the dissimilarity matrix rather
than raw data R value ranges from -1 to +1.
AMBI (AZTI’s Marine Biotic Index): To get the ecological
quality status of (EcoQS) benthic environment, biotic indices
like AMBI (AZTI’s Marine Biotic Index) are crucial. AMBI [13,14]
used different soft bottom macrofauna for benthic quality
assessment and classified them into 5 groups.
Group 1: Sensitive species, present only in uncontaminated
Group 2: Organisms unresponsive to organic enrichment
with low densities.
Group 3: Tolerant species may occur in normal conditions
and proliferated when organic enrichment occurs.
Group 4: Second order opportunist species with small size.
Group 5: First order opportunist species.
According to Muxika et al. , biotic coefficient value of
AMBI from 0 - 1.2 is classified as normal community, undisturbed
site and high ecological status.
1.2-3.3: Unbalanced community, slightly disturbed site, Good
3.3- 4.3: Transitional to pollution, moderately disturbed site,
moderate ecological status
4.3 - 5: Polluted community, poor status
5 - 5.5: Transitional to heavy pollution, heavily disturbed
Fort Cochin and Dharmadam beaches are sandy beaches,
but certain sections of Dharmadam beach hold laterite rock formation on sandy crypt (Figure 2). Dharmadam laterite rocks
are mainly composed of iron oxides and a laterite cliff can also
be seen at Dharmadam rocky area. A green island located nearly
100m distance of shore also holds lateritic rock formation,
which highlights the geological importance of Dharmadam
beach. This beach is flat and wide with fine sediments, mainly
composed of mica. The mica flat flakes of the surface of the
beach grains glint in light on sunny days (Figure 3). Mangroves
and other vegetation are abundant on the rock cliff of the beach.
Besides this, adjacent Dharmadam Island is also spotted as a
mangrove area. Fort Cochin beach is also a sandy beach with
coarser sand and it is highly attracted by tourists due to the
existence of Chinese dip nets, a unique lure of Fort Cochin beach.
Fort Cochin beach has an extensive berm with much steeper
slope when compared to Dharmadam beach. During south-west
monsoon (June-September) rigorous sea erosion takes place.
Consequently sea walls and groins have constructed to avoid
sea erosion. In October and December 2009, Fort Cochin beach
exhibited accretion of sand and a wide portion of newly accreted
sediment had been formed along with the beach. At Dharmadam
beach also the erosion tendency of beach persists at south-west
monsoon but comparatively the accretion tendency is lesser
than that of Fort Cochin beach.
Wave action is more intense in Fort Cochin than Dharmadm
beach and the frequency of waves is different in both beaches.
Number of waves per minute at Fort Cochin was 9 (avg.) and
time frequency was 5-8 seconds and in Dharmadam it was
6 no. /minute (avg.) and the time frequency was 6-9 seconds.
Waves do not typically reach the beach perfectly parallel to the
shoreline; they arrive slightly deviated to an angle to the beach.
Angle of approach of waves at Fort Cochin was 100-1100 and at
Dharmadam it was 90-1100. Coastal tidal ranges vary globally
and it will be from near zero to over 11 meters. When the tidal
range is lower than 2 meters it is classified as micromareal. Here
at both the beaches maximum tidal amplitude was 1.3m, so it
is classified under micro tidal region. The speed of Long shore
current at Fort Cochin was 0.025-0.038m/s and in Dharmadam
it was 0.023 -0.034m/s.
Ripple formation was a common feature in Dharmadam
beach. According to Chakrabarti  energy levels of waves
and currents of intertidal region exert strong control on ripple
formation patterns. In Dharmadam ripple formation was
observed in almost all the months during the sampling, however
in Fort Cochin it was totally absent. The ripple observed was
somewhat symmetrical and formed as a result of back and
forth motion of wave action. The upper crest of the ripple was
not so straight. Tidal channel is also a permanent feature in
Dharmadam beach and it is important for the birds and marine
larval forms. The channel observed to be deep in monsoon
season due to high influx of water and shallow during pre and
post-monsoon season. Laterite rock formation of Dharmadam
beach also gives numerous micro habitats to the epifauna as it has lot of holes on rocks and small tide pools. The iron oxide rich
laterite rocks are frail and change in shape and position was also
observed seasonally during the study. Weathering of rocks may
increase due to intense wave action of rocky areas.
Avian fauna were also observed from both the beaches
and it was observed that eagles and crows were common in
both the beaches and sea gulls and king fisher’s were observed
occasionally at Dharmadam beach. The honey comb like
structures of sand, underneath the rocks were also another
attraction of Dharmadam beach. These are made by sand castle
worms and these sandy formations are very delicate. Sand castle
worms are abundant in low tide region and they are exposed
only in lowest low tides (Figure 4).
Faunal characteristics of both the beaches showed disparity
in some groups and similarity in some. At Fort Cochin beach two
stations were selected for the study at a distance of 500m. Twenty
four species were identified from both the stations of Fort Cochin
beach and dominant groups identified were amphipods (42%)
followed by polychaetes (28%). In addition to these, bivalves
(Donax sp.), polychaetes (Neries sp., Heteromastus sp., capitella
capitata, mediomastus capensis, puliella armta, notomastus
sp.), oligochaetes, mole crabs (Emerita sp, Emerita rathbunae),
amphipods (Amphilochus picadurus, Paramicrodeutopus schmitti,
Microdeutopus gryllotalpa, Gammaropsis sp, Gnathopleustes
sp, Hyalella sp. Callopius carinatus), Ispopods (Spheromopsis
sp.), mysids and tanaids, were also observed. The beach at Fort
Cochin produced fewer species and the vertical distribution of
organisms was not consistent throughout the sampling (Figures
5 & 6).
From the two stations observed in Dharmadam beach zone,
about thirty four species of macro invertebrates were obtained.
Among the identified samples, gastropods (Turbo sp., Nassarius
sp., Trochus maculatus, Natica genuosa, Cymasium sp, Bufonaria
sp., Turricula sp.), tanaids, and polychaetes (Scoleepis squamata,
Glycera longipinnis sp., Paraonides sp, Glycera sp, Nereis sp. Neries
willeyi, Prionospio cirrobranchiata, Prionospio ehlersi, Prionospio
sp., Priospio sexoculata, Oweni ssp., Spio filcornis) formed the
dominant organisms. The number of tanaids (43.4%) was highest
at station1 when compared to other groups, whereas in station
2, gastropods (45.54%) were dominant. Shore crabs (Ocypode
sp, juveniles of Ocypods, Dotilla sp.), hermit crabs (Diogene
sp.), mole crabs (Emerita holthuissi, Emerita talpoida), bivalves
(Donax sp., Perna viridis, Crassostrea madrasensis), amphipods
(Pontocraytes altamarinus), isopods (Eurydice peraticis and
Sphaeromopsis sp.), sea urchins (Psammechinus milaris), sea
stars (Astropecten irregularis) were also observed as well.
The distribution of organisms from HTM to LTM was almost
consistent throughout the sampling (Figures 7 & 8) and vertical
distribution of organisms was prominent on rocks of Dharmadam
beach. The epifauna residing there are mainly isopods (Ligia
sp.), gastropods (Littorina sp, Patella sp.) etc. Bivalves observed were Perna viridis and Crassostrea madrasensis. Barnacles
(Semibalanus balanoides) and sea anemones were also identified
from the spot.
Both the beaches have shore vegetation near to the shore
line and Dharmadam beach embraces variety of flora when
compared to Fort Cochin beach. Vegetation on the beach plays
a significant role in beach stabilization, erosion and prevention.
The major plants observed from the Dharmadam beach were
coconut trees (Coccos nucifera), Pandanus sp, Casuarina sp, beach
morning glory or rail road vine (Ipomoea pescaprae) (Figure 9),
mangroves, almond tree (Badam) etc. A small forest of Casuarina
spi. is also present in the shore line of the Dharmadam beach.
At Fort Cochin the major plants observed were coconut trees
(Coccos nucifera), May flower tree or gulmohar (Delonix regia),
Jarul (Lagerstroemia speciosa), banyan tree (Ficus bengalensis),
rail road vines (Ipomoea pescaprae) etc.
In Fort Cochin beach (Station 1), seasonal diversity index
showed highest diversity in post- monsoon season, 2009 (Postmonsoon
1) (H’= 1.13) with high species richness (d=1.3).
Species evenness was observed high in post-monsoon season,
2010 (post-monsoon 2) (j’= 0.99) with lesser dominance of
species (λ’= 0.33). Lesser diversity was observed in monsoon
season, 2010 (Monsoon 2) (H’=0.80) (Table 1).
In station 2 diversity index showed higher diversity with less
species dominance in monsoon, 2009 (Monsoon 1) (H’= 1.3, λ’=
0.26). Post-monsoon season, 2010 (Post-monsoon 2) showed
lesser diversity when compared to other seasons (H’= 0.79).
High evenness was shown in monsoon season, 2009 (j’= 0.98)
and high richness was observed in post-monsoon season, 2009
(Post-monsoon 1) (d=0.923) (Table 2).
Seasonal diversity index showed higher diversity in
Monsoon, 2009 (Monsoon 1) Dharmadam beach (station 1)
(H’=1.58) with low dominance of species (λ’ = 0.20). Premonsoon
season, 2010 showed higher species richness (d=1.71)
and higher species evenness was shown in monsoon season,
2009 (Monsoon 1) (j’=0.98). Higher dominance was observed in
post-monsoon season, 2009 (Post-monsoon 1) (λ’= 0.42) with
uneven distribution (j’= 0.64). A decreasing trend of diversity
was observed from season to season (monsoon, 2009 to postmonsoon,
2010) (Table 3).
In station 2 diversity index showed higher diversity in
post-monsoon season, 2009 (Post-monsoon 1) (H’=1.86) with
lesser dominance (λ’ = 0.17). Species evenness was more in
pre-monsoon season, 2010 (j’=0.92) with lesser richness of
species (d= 0.97) and high species richness was observed in
post-monsoon season, 2010 (d= 1.59). Monsoon, 2010 showed
lesser diversity (H’= 1.42) with comparatively even distribution
of species (d= 0.88) (Table 4).
Caswell neutral model was applied to seasonal abundance
data to compare the Shannon Wiener diversity (H’) with the
predicted diversity values (E [H’]) as proposed by Caswell in his neutral model, measures theoretical diversity for a sample
of observed number of species (S) and individuals (N) under
model assembly rules for the community, which are ecologically
neutral . In Fort Cochin (station 1), the V value was negative
in monsoon, post-monsoon (2009) and pre-monsoon (2010)
seasons (-0.79, -0.66 and -0.90 in monsoon, post and premonsoon
season- respectively). The predicted diversity values
were also higher than actual diversity values (E [H’] = 1.1 and
H’ = 0.92 in monsoon season, E [H’] = 1.2 and H’ = 1.1 in post
monsoon season, E [H’] = 0.99 and H’= 0.81 in pre-monsoon
season), indicating lesser diversity values than ‘neutrality’.
in monsoon and pre-monsoon season (Table 5), might be an
indication of any disturbances to the assemblage during that
time. In Fort Cochin (station 2) monsoon season (2010) showed
negative V value (-0.3) and higher predicted diversity (0.94)
than actual diversity (0.85). Other seasons showed positive V
value indicating greater diversity than ‘neutrality’ (Table 6). In
Dharmadam beach (Station 1), pre monsoon season showed
negative V value and higher predicted diversity (E[H’] = 1.5),
which might be due to excessive dominance of species (Table
7). In station 2, all seasons exhibited positive V value, indicating
greater diversity than neutrality (Table 8).
Twelve water quality parameters have been identified
from the study area. Temperature, pH, Salinity, carbon dioxide,
dissolved oxygen, conductivity, TDS, turbidity, phosphate,
silicate, nitrate and nitrite. Total faunal groups in Fort Cochin
beach with dissolved oxygen illustrated R value as -0.059 and
significance level was greater than 0.05 (p < 81%, p > 0.05).
This near zero R value indicates no significant segregation of
samples with DO variation. Gastropods showed 0.053 R value
and significance level greater than 0.05 (p< 14%, p> 0.05) with
salinity in Dharmadam beach. Amphipods showed -0.035 R
value and significance level was greater (p< 88%, p> 0.05) with
salinity in Fort Cochin beach. Total faunal groups in Dharmadam
beach showed global R value as 0.03 and significance level
greater than 0.05 (p< 17%, p > 0.05) with dissolved oxygen.
Polychaetes in Dharmadam beach showed -0.024 R value and
significance level was p< 71%, p > 0.05 with temperature and in
Fort Cochin polychaetes showed -0.072 R value and significance
level greater than 0.05 (p < 93%, p> 0.05) with temperature. The
all above mentioned analyses were shown near zero R value and
consequently no significant segregation with abiotic factors was
Similarity of polychaetes, amphipods and gastropods were
observed with tide height to discern their significance level
with different tidal height. Gastropods from Dharmadam beach
showed no significant segregation with tide height (R = 0.09,
p> 0.05) (Figure 10). Amphipods from Fort Cochin beach also
demonstrated that there was no significant segregation with
tidal height (R=0.04, p > 0.05) as per ANOSIM analysis (Figure
11). Polychaetes from both the beaches were also observed and
in both Fort Cochin and Dharmadam beaches the polychaetes
illustrated no significant segregation with tidal height (R = 0.02,
p > 0.05 and R = -0.067, p > 0.05) (Figures 12 & 13). All the R
values observed were close to zero, as per Clarke et al. , R
values close to zero implying no segregation between samples.
The significance level observed were also higher than alpha
significance value (0.05), indicating no significance between
For the assessment of benthic quality of the selected beaches
AMBI was calculated and according to AMBI classification
macrofauna were classified into five ecological groups based on
the organism’s sensitivity to stress. In Fort Cochin beach (station
1), AMBI index explained that the observed macrofauna were
coming under group 1. Group 1 species are very sensitive to
organic enrichment and present only in non polluted condition.
The AMBI index value was 0.867, according to the classification
the value in between 0-1.2 is classified as an unpolluted
condition with high ecological status. According to AMBI
analysis Fort Cochin beach (station 1) confirmed as unpolluted
beach with sensitive organism (Figure 14). In station 2 the
AMBI index showed dominance of group 3 organisms, these are
tolerant species and may present in normal conditions and if
organic enrichment occurs, the population increases. The AMBI value was 3.5 and the value 3.2 - 5 is considered as moderately
polluted condition with moderate ecological status. The benthic
community health is transitional to pollution in station 2
according to AMBI classification (Figure 15).
In Dharmadam beach (station 1) AMBI index explained
dominance of group 2 organisms. According to the classification
the group 2 organisms are species unresponsive to enrichment
and variation is less with time. The AMBI value was 1.491, it is
coming under slightly disturbed nature with good ecological
status according to the classification. An unbalanced community
health was observed in station 1 (Figure 16) and the value
from 1.2-3.2 is considered as slightly polluted. In station 2,
organisms were coming under group 2 and AMBI value was
1.545, subsequently it was classified under slightly disturbed
with good ecological status (Figure 17).
Fort Cochin beach is known for its beauty; nevertheless the
human interactions are more prominent in this beach. There
are many sources of pollution like industrial effluents, fishing,
run off from near areas, shipping (oil slicks) and tourism etc. In addition to this, dead and decaying Eichornia washed towards
the beach also creates disturbances to the intertidal organisms
(Figure 18). Dharmadam beach is pristine natured with fishing
being the only major human activity, tourism is in early stage
as the Dharmadam Island nearby beach and rocky outcrops of
the beach fascinate tourists (Figure 19). Fishing operations are
mainly by traditional boats and nets.
In spite of the fact that the Fort Cochin and Dharmadam
shorelines are sandy in nature however in morphology and in
faunal composition they are indicating diverse appearance.
Fundamentally, shore morphology is a component of waves
and sediment [16,17]. A range of additional processes, such as
tide and wind, additionally impact the shore morphodynamics.
Morphological contrasts are more prominent in the chose
shorelines; based on sediment, Fort Cochin holds coarse
sand whereas Dharmadam shoreline embraces fine sand. The
morphology of a beach results from the interactions between the
available sediment and the energy of the waves impinging on the
shoreline [16,17]. The gentle steep nature of Fort Cochin beach
and flat nature of Dharmadam beach show the intensity of waves
on those beaches.
Rather high intense nature of waves of Fort Cochin than
Dharmadam endorses the profile difference of both the beaches.
Fine sediments absorb a little water but coarse sediments absorb
more water that flows up and down the beach . Most of the
beaches in Kerala show evidence of erosion and deposition
owing to waves of monsoon and fair whether seasons. During
October to March all the beaches show accreting tendency
under the influence of north westerly waves . Fort Cochin
beach is more prone to accretion and erosion than Dharmadam
beach due to intense wave action and deposition of sand in the
banks of Cochin estuary by dredging activities. Rocky outcrops
of Dharmadam seashore increase the geological importance of
that field and the laterite rocks found there are primary laterites,
weathering product of basalt. The green island placed within
the close shore at a hundred meter in the direction of west of
Dharmadam is fashioned by highly eroded main laterites .
These iron oxide rich rocks are domicile of exclusive
organism; it has acquired plenty of suitable habitats for organisms
to survive than fort Cochin beach. Mangroves are also observed from Cochin estuary and Dharmadam , Dharmadam beach
rock cliff is full of mangrove vegetation. As a consequence the
ecological value of seashore raises as it’s the best coastal habitats
on this planet. The presence of mangroves in the rock cliffs of the
seashore suggests the healthy atmosphere of Dharmadam beach.
The island close to the Dharmadam beach additionally keeps
bunch of vegetation and migratory birds. Sandy shores are highly
dynamic in nature, Macrobenthic communities match well with
the physical classification of sandy beaches, and the combined
effect of wave energy, sand particle size and beach slope was
once proposed as these are predominant factors influencing the
macrofauna assemblage in intertidal ecosystem .
Vegetation of both the shores is showing disparity in their
composition, it can be noticed easily as herbs and shrubs are
further unique in Dharmadam beach, even as Fort Cochin has
obtained lot of bushes. In most ecosystems, community structure
appears as an outcome of the complex interaction among biotic
and environmental variables . The Shannon Wiener diversity
index of Dharmadam beach showed that the beach system
supports high abundance of two or three species which has led
to less species richness as well as low species evenness. Species
richness and diversity were comparatively higher in Dharmadam
beach than Fort Cochin beach in seasonal observation. Taheri et
al.  observed low diversity of macrofauna in monsoon season
in Oman Gulf, but the present study observed high diversity in
station 1 of Dharmadam and station 2 of Fort Cochin beach in
monsoon season (2009).
One or a few species dominating a community shows
low evenness while those communities that have more even
distribution will have high evenness. The low species evenness
observed in both the beaches corroborates the statement,
indicating low ecosystem health as high evenness of species is an
indication of healthy ecosystem. Nevertheless species evenness
is not able to be held liable for the system health, the diversity
also taking principal position. The distribution of organisms
was not even in seasonal observations in both the beaches,
indicating less diversity of species. The evenness component
varied in compliance with H’. Communities with lower number
of organisms that are dominated by one or a few species are least
diverse. Some studies revealed that sandy beach ecosystems
wherein species evenness and diversity are influenced by the
population dynamics of numerically abundant species [23,24].
The study upholds this statement, at Fort Cochin beach among
polychaetes, Capitella capitata was found to be abundant in
station 2, where species evenness and diversity were observed
to be low.
AMBI [14,15] was performed to know the community
disturbance and ecological status of the system. In Fort Cochin
beach (Station 1) AMBI calculation illustrated undisturbed
condition and moderate polluted condition in station 2.
Polychaetes were observed to be absent in Fort Cochin beach (Station 1) except Arenicola, however Eichornia wrack was
persistent throughout the sampling in Fort Cochin beach (station
1). From the above findings it may be assumed that the species
present in station 1 have the capacity to self adapt with the
stress condition. In Fort Cochin beach (station 2) opportunistic
polychaete species were copious and the circumstance agrees
with the findings of biotic index. In Dharmadam beach high
and good ecological status were observed in AMBI, however the
community from Dharmadam beach was observed to be slightly
disturbed when AMBI was performed.
The presence of opportunistic species like Scolelepis and
Prionospio species in Dharmadam beach could be connected
to the AMBI results. From this it could be assumed that the
pristine nature of Dhramadam beach could be altered in future
due to human activities and the accumulation of opportunistic
polychaetes may be an indication to that. Based on the above
findings, it is clearly observed that the Fort Cochin beach is
under peril due to anthropogenic effects and the proliferation
of r selected species (opportunistic) depicts the above fact.
Elimination of k selected (species found in undisturbed
conditions) species in Fort Cochin beach (Station 2) stating the
notable effects of human activities in station 2. If the activities
sustain constantly, it will lead to the ecosystem damage in near
Although the Dharmadam beach is in a good ecological status,
the slightly disturbed community there giving an alarming fact
that the proliferation of opportunistic species have started out
and it is far pointing out the disturbances over there. Community
disturbances may not be completely of anthropogenic stresses;
however it may be due to changes in sediment structure, physical
factors or food resources and anthropogenic disturbances also
affect the water quality and organisms of that area. Studies
have shown that anthropogenic activities may affect the animal
physiology like growth rate, recruitment and mortality [25,26].
This study emphasizes the fact that these beaches are vulnerable
to rigorous human activities. Most of the exposed beaches in
south-west coast of India have prone to anthropogenic activities,
like fishing, tourisms, industries and shipping industries.
These activities slowly transform the biotic communities of
the beach ecosystem, which affects the food web and survival
capacity of other faunal communities surviving there. Beaches
are not only for recreational purpose but also it has a prominent
role in coastal health. Misuse of beaches will lead to coastal
ecosystem damage and the sustainability of coastal ecosystems
is imperative as it influences the climatic changes and coastal life.
Coastal zones restrain assorted and fruitful habitats imperative
for anthropogenic actions and survival. Management of beaches
and protection of their unique biodiversity necessitates
intercession. In addition to direct anthropogenic impacts on
beaches, global climate change also has various consequences for the intertidal ecosystem. Thus, management and conservation
of the unique ecological features and processes of beaches have
become critical and an imperative concern.
Coastal zone regulation act (2011) of Ministry of Environment
and Forests, Govt. of India, restricts all developmental activities
and waste disposal within 500m of high tide zone of the intertidal
region that comes under CRZ 1, the most ecologically sensitive
zone. However, gross violation has been observed in Fort Cochin
beach; probably in the near future there is a potential threat from
intense human interventions in that beach and adjoining areas.
Therefore based on the study, the following recommendations
are put forth for effective management of the degrading littoral
region of the Fort Cochin beach.
The Fort Cochin beach and adjoining areas are severely
impacted, so it is proposed to have a “holiday period” to
regulate the various increasing human activities (Fishing,
mining and industrial) so that the ecosystem rejuvenates to
its pristine condition.
The general awareness and ecological importance of
the intertidal zones are to be given more thrust along with
the concept of protection and conservation of our marine
Necessary modifications need to be implemented by
the regulatory bodies to include the littoral zones and other
coastal zones under the Marine Protected Areas (MPA) in
category 1 for overall protection and conservation of the