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Chapter 6
RESULTS AND DISCUSSION
6.1. STUDY DESIGN
he problem of wetland biodiversity and sustainable development
forms the fundamental base of the present study, involving three
panchayats namely Kainakari, Edathuva and Ala, in an altitudinal
line from west to east in the Kuttanad wetland system. The comparative
analysis of the data generated has been made so as to gain information on
biodiversity particularly in terms of vegetational wealth as a major
component. The above analysis has been followed by the identification of
the areas for conservation, agroforestry development and occupational
pattern in order to obtain sustainability and compatibility with the ecosystem
has been attempted. Care has been taken to identify traditional knowledge
and technologies, which stand vanished but have the potential to be revived
and made sustainable. It is hoped that the totality of information should result
in evolving micro level biodiversity database in a wetland system and which
could be a model for such studies particularly with wetland, which is one of
the most fragile ecosystems.
6.2. ANALYSIS OF SPATIAL DATA
All the thematic maps included in the thesis were produced using
ArcGIS 9.3 version (GIS software). The geological information presented
covers only the land use pattern and vegetation difference of the study area.
T
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6.2.1. Kuttanad land use
Kuttanad is divided into four zones on ecological basis and six zones on
agro-ecological basis. The land use is a distinguishing feature of a wetland
from which diverse livelihoods have emerged. Paddy is the most suited land
use for livelihoods in covering 26 % of the land area. Kuttanad has an area of
1,10,000 ha, which is divided into four ecological zones (map 03). These with
approximate area are the Garden or dry land (31,000 ha), Wetland (11,000
ha), Reclaimed land situated below sea level (55,000 ha), and Water bodies
including lake, canals, etc. (13,000 ha). The garden land is elevated region
situated at 0.5 to 2.5 m above MSL, where predominant crops are coconut,
cocoa, tapioca, banana, pepper and vegetables (Swaminathan, 2007).
Wetland areas are waterlogged low formations measuring 66,000 ha
and located either above MSL or 0.60 to 2.20 m below MSL, reclaimed from
the surrounding backwaters for paddy cultivation. Of this, 55,000 ha area
below MSL is known as punja lands. These polders reclaimed from Kayal area
with an outer or ring bund are made into cluster of fields called
„Padasekharams‟. Remaining 11,000 ha of wetland is relatively elevated and
forms part of Upper Kuttanad. The punja land located in Kuttanad is further
classified as Karappadam land (33,000 ha), Kayal land (13,000 ha), and Kari
land (9,000 ha). Karappadam lands are areas of alluvial soils situated along
waterways and constitute the lower reaches of the eastern and southern
periphery. Kayal lands constitute padashekharams recently reclaimed from
the Vembanad Lake with elevations between 1.5 to 2.2 m below MSL (map
07).
6.2.2. Land use pattern and vegetation index
The application of GIS in the present investigation is restricted to the
interpretation of land use and vegetational components in the three
panchayats (map 08-10). A comparative study of map shows that there is
thick vegetation in Ala panchayat, gragually reducing in Edathuva and
Kainakari respectively, with increase in water bodies. The above situation is
substantiated by decreasing number of flowering plants, from 392 species in
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Ala, to 360 in Edathuva and 299 in Kainakari. Similarly, the land use for
habitational purposes is high in Ala, less in Edathuva and least in Kainakari.
6.3. ANALYSIS OF BIODIVERSITY RESOURCES DATA
6.3.1. Floral diversity
6.3.1.1. Floral diversity of Kainakari panchayat
299 species of plants belonging to 244 genera and 80 families have
been recorded from Kainakari panchayat and this count comes only 71.3 %
of the total recorded flora. Among these 29.7% (89 species) were wetland
dependent) and 5.3% (16 species) were endemic category. 67% (200 species)
of the total flora recorded from this panchayat were dicotyledons and 33%
(99 species) were monocotyledons (graph 18). Most diversified dicot families
in this panchayat were Euphorbiaceae (12 species), Malvaceae (11 species)
Papilionaceae (10 species) and Verbenaceae (11 species), and monocot
families were Poaceae (33 species) and Cyperaceae (21 species). 64 species
of trees, 51 species of shrubs, 158 species of herbs and 26 species of
creepers/climbers have been noted from the total 299 flora documented
from the panchayat.
6.3.1.2. Floral diversity of Edathuva panchayat
360 species of plants belonging to 273 genera and 98 families were
observed from Edathuva panchayat, of which 24% (87 species) were
included in wetland dependent and 4.4% (16 species) were in endemic
category. 74.7% (269 species) of the total flora recorded from this panchayat
were dicotyledons and 25.2% (91 species) were monocotyledons (graph 18).
Most diversified dicot families in this panchayat were Euphorbiaceae (16
species), Malvaceae (11 species) Papilionaceae (13 species) and
Verbenaceae (11 species), and monocot families were Poaceae (33 species)
and Cyperaceae (21 species). Out of the 360 angiosperms recorded from the
panchayat, 96 species were trees, 76 species were shrubs, 162 species were
herbs and 29 species were climbers/creepers.
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6.3.1.3. Floral diversity of Ala panchayat
Out of 419 species of flowering plants recorded from the three study
panchayats, 392 species (93.5% of total flora) belonging to 279 genera and
100 families could be observed from Ala panchayat, among them only 18.8 %
(74 species) were noted as wetland dependent species and 3% (15 species)
were noted as endemic status. 78% (307 species) of the total flowering plants
recorded from this panchayat were dicotyledons and 22% (85 species) were
monocotyledons (graph 18). Most diversified dicot families in the panchayat
were Apocynaceae (10 species), Caesalpinaceae (10 species),
Euphorbiaceae (18 species), Malvaceae (12 species), Myrtaceae (10
species), Papilionaceae (14 species), Rubiaceae (12 species) and
Verbenaceae (12 species) whereas most diversified monocot families were
Poaceae (29 species) and Cypreaceae (20 species). Classification of the
flora based on the habit showed that 126 species were trees, 82 species were
shrubs, 152 species were herbs and 32 species were climbers/creepers.
6.3.1.4. Comparative analysis
Within wetlands, vegetation is known to be a useful indicator of biotic
integrity (Simon et al., 2001; Albert and Minc, 2004). Plant communities
respond to water quality, hydrologic modifications, chemical pollution, and
nutrient enrichment (Lopez and Fennessy, 2002; Albert and Minc, 2004).
Submergent species richness is affected by high sediment levels, nutrient
enrichment and turbidity, while emergent species also respond to culturally
enriched inputs (reviewed in Van Wieren and Zorn, 2005). Ground vegetation
is acutely sensitive to finer-scale disturbances in microclimate (soil moisture
and temperature), so it is an integral early indicator of changes in wetland
health (Simon et al., 2001; Albert and Minc, 2004).
Of the total 419 plant taxa recorded from the entire study area, 93.5%
(392 species) were observed from Ala panchayat, 74. 7% (360 species) were
observed from Edathuva and 71.3% (299 species) were observed from
Kainakari panchayat. Over a half of the (62%) naturalized vegetations are
common to all the three panchayat with variation in distribution and density.
However, a significant reduction in the species diversity of plants could be
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noted from upper Ala to middle Edathuva and to lower Kainakari panchayats
(Table 24).
Out of 392, 360 and 299 species of flowering plants recorded from Ala,
Edathuva and Kainakari panchayats, 74 species (18.8%), 87 species (24%) and
89 species (29.7%) respectively were noted as wetland dependent plants
(graph 06). Considering nativity status 15 species (3%) of Ala, 16 species (4.4%)
of Edathuva and 16 species (5.3%) were noted as endemic. The above data
showed that the species diversity of wetland dependent plants increased
with increasing areas of wetland from Ala panchayat (upper Kuttanad) to
Kainakari panchayat (lower Kuttanad). Similarly, endemism also showed an
increasing trend from Ala to Edathuva and to Kainakari panchayats (graph
07).
Of the total flowering plants recorded from the three panchayats, 23
were noted as endemic species of which 2 species, namely Ischaemum
travencorense and Ischaemum vembanadense were exclusively endemic to
Kerala (Sunil and Sivadasan, 2009). Further, 19 species of plants were reported
as Globally /nationally threatened species which included Endangered,
Critically endangered, Vulnerable, Rare and Low risk/near threatened
category. Species namely Artocarpus hirsutus, Garcinia gummi-gutta, Hopea
parviflora, Hydnocarpus pentandra, Myristica malabarica and Vateria indica
were recorded as both endemic and threatened category.
The tree species in the study area are reported to be flood tolerant. This
tolerance is exhibited not only in the ability of individual trees to survive a
certain amount of flooding, but also the ability of these species to generate
new trees through root suckering. The use of trees for commercial biomass
production has recently gained interest on agricultural land (i.e. agroforestry).
Planting trees for agroforestry around wetlands may help to extract and
remove excess nutrients. Trees may be even more effective than some
forages, by using more extensive and deeper root systems to recapture deep
leached nutrients (Jeffries and Mills, 1990).
It is very important to note that the tree wealth of Kainakari and
Edathuva panchayat are significantly less than that of the Ala. In Ala
panchayat 126 species of total recorded flowering plants (392 species) are
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trees, shows 32% of the total flora covered tree elements, whereas in
Edathuva and Kainakari panchayats only 96 species (out of 360) and 64
species (out of 299) respectively are noted as in the category of tree. The
results showed that tree wealth of Edathuva and Kainakari panchayat are
much less being 26% and 21% respectively of the total flora. A major concern
with growing trees in this part of the landscape is the risk of flood damage.
This depends on the risk of a flood event, the duration of flooding and soil
saturation, the flood tolerance of the tree species, and the expected harvest
interval of the tree crop.
6.3.1.5. Aquatic macrophytes
An aquatic plant may experience abundant soil moisture during the
entire growing season, but water levels drop during the dry season or summer
months, when these types of plants commonly experience severe water stress
and dormancy if water recedes or soil around the root system becomes very
dry. One or a few species of emergent aquatic plants can dominate the
freshwater community. Most of these grow aggressively via rhizomes or
stolons, crowding out other species. Rhizomes permit these plants to endure
periods of environmental stress, and the rhizome (or corm) is the overwintering
bud of plants growing in cold climates (Jeffries and Mills, 1990).
Under full sun and non-limiting nutrients, a single individual can be
introduced into a water medium and multiply rapidly by vegetative means.
Water-lettuce, Pistia stratiotes, forms new plants around the mother plant
from underwater stolons. Water-hyacinth (Eichhornia crassipes), and floating
fern species of Salvinia and Azolla also show explosive population growth. In
the tropics and quiet waters of ponds and lakes, such species can completely
cover the water surface within several months, and for that reason are
considered pernicious aquatic weeds, which are removed at great expense
and trouble because they clog channels and choke out other forms of life in
the body of water.
Aquatic macrophytes acts as indicators of water quality, reduce
pollution by acting as nutrient pumps, provide suitable breeding and
sheltered places for varied aquatic fauna and support large quantities of
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epiphytic algae. It is also a source of food in the trophic relationships of
wetland ecosystems (Trisal, 1990). Submerged macrophytes also release
oxygen which adds to the dissolved oxygen content of the water. An
important adaptation for many freshwater aquatic plants is the formation of
aerenchyma.
Kuttanad wetland system provides wide a variety of aquatic habitats
like rivers, streams, pools, ponds, paddles, lakes, etc., each harboring
characteristic type of vegetation. Among 91 aquatic/semi-aquatic plants 73
species are common to all the three panchayats and this included both
native and non-native species representing every category of wetland
indicator status (table 25). Dominant wetland dependent taxa common to
the three panchayats are Centella asiatica, Colocasia esculenta, Cyperus
bifax, Cyperus pilosus, Eichhornia crassipes, Fimbristylis ferruginea, Hydrilla
verticillata, Lagenandra toxicaria, Limnocharis flava, Nymphaea pubescens,
Polygonum barbatum and Typha angustata. It is interesting to note that over
97% (89 species out of 91) of the recorded wetland dependent floral
components has been documented from Kainakari panchayat, the area
having expansive paddy fields and water bodies, which forms the ideal
habitat for all kinds of wetland plants. Similarly, Edathuva panchayat
represented 95% (87 species out of 91) of the recorded wetland dependent
plants, the area is somewhat similar to the Kainakari panchayat. On the other
hand, only 80% (74 species out of 91) of the total recorded wetland
dependent floral components could be represented by Ala panchayat, must
be because the area is located in the upper reaches of Kuttanad wetlands.
6.3.1.6. Weed invasion
Many wetland plants fit the definition of “invasive plants” as species or
strains that rapidly increase their spatial distribution by expanding into native
plant communities (Richardson et al., 2000). Most of them not only affect local
biodiversity and ecosystem functioning but also human use and employment
generation. A few affect ecosystem functions both directly and indirectly.
Direct impacts involve canopy height and other attributes of architecture,
shifts from herbaceous to woody plants (or vice versa), increased productivity
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and litter, different litter break down rates, altered nutrient regimes, and either
increased or decreased flammability. Indirect impacts concern associations
with microorganisms such as bacteria and mycorrhizae and larger
invertebrate and vertebrate animals. Invasive wetland plants are generally
assumed to reduce both plant and animal diversity, and excessive weed
growth in the Kuttanad water bodies confirms this assumption (Werner and
Zedler, 2002).
The weed flora provides an indigenous source of fertilizers, acting as soil
conditioner, when utilized as compost manure (Naskar, 1990). In Kuttanad
wetland ecosystems, the aquatic weeds are chiefly responsible for chocking
water bodies, which do not allow water animals such as fish and turtle to
move freely, reduce the productivity by preventing sunlight to reach down to
bottom soil and depleting nutrients, lowering down the amount of dissolved
oxygen and providing shelter to many organisms, e.g. pathogens and
parasites.
Out of 91 wetland plant species recorded, 61 species are ascribed as
weedy elements and which included both native and exotic species. About
10 species of documented aquatic weeds are exotic. Important among them
are Alternanthera philoxeroids, Cabomba carolianiana, Commelina
benghalensis, Eichhornia crassipes, Impatiens diversifolia, Limnocharis flava,
Ludwigia adscendens, Monochoria vaginalis, Pistia stratiotes, Polygonum
barbatum and Sagittaria guayanensis. Albert and Minc (2004) suggested that
coverage of non-native species is a good measure of wetland condition, as
wetlands within heavily urbanized environments tend to be dominated by
non-native species (John, 2011). Ipomoea aquatica, Cyperus pilosus, and
Brachiaria mutica are moderate in abundance and grow in patches or
interspersed in Kainakari and Edathuva panchayats.
6.3.2. phytoplankton resources
6.3.2.1. Diversity and distribution
Phytoplanktons are defined as free floating unicellular, filamentous and
colonial organisms that grow photo-autotrophically in aquatic environments.
They are the basis of food chains and food webs which directly provide food
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for zooplankton, fishes and some aquatic animals (Millman et al., 2005;
Shubert, 1984). The phytoplanktons in a water body are an important
biological indicator of the water quality and also are predominant primary
producers and the basis of the food chain in open water habitats. The
diversity, distribution, abundance and variation in phytoplankton give reliable
information on energy turnover in an aquatic system. Their sensitivity and
substantial variations in species structure often provide an indication of
significant change in ambient conditions within an ecosystem and they are
considered as good indicators of water quality. Phytoplankton studies and
monitoring are useful for the control of the physico-chemical and biological
conditions of the water (Devi et al., 2012).
In the present investigation on the biological resources assessment of
Kuttanad wetlands, a total of 109 species of phytoplanktons are reported
from the three different panchayat locations such as Kainakari, Edathuva and
Ala together. Earlier workers such as George (1958), Nair and Tranter (1971),
Haridas et al. (1973) and Kunjukrishna Pillai et al., (1975) have made an
attempt to determine the status of plankton population in the Cochin
backwaters and Vembanad Lake, but the investigations could not provide
the actual quantitative status of the phytoplankton in the Vembanad lake of
Kuttanad wetlands. The species elements belong to 6 major classes covering
Cyanophyceae, Chlorophyceae, Bacillariophyceae, Euglenophyceae,
Dinophyceae and Chrysophyceae. While comparing the species diversity,
Chlorophyceae composed of 60 species, and forms the most diversified class
with 57.79%, from the total phytoplankton group of the study location. 27
species are belonging to Bacillariophyceae (24.77%), 12 species belonging to
Cyanophyceae (11%), 4 species belonging to Euglenophyceae (3.66%) and 3
species belonging to Dinophyceae (2.75%). Class Chrysophyceae
represented by only one species with 0.92%, formed the least diversified class
and was reported only from the lower reaches of Kuttanad wetland namely
Kainakari panchayat.
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6.3.2.2. Comparative analysis of phytoplankton
Phytoplankton can be found all over the world. It can exist in
temperate regions and tropical regions but the effects of different latitudes
on the distribution of phytoplankton are not clear. In temperate latitudes, the
growth of phytoplankton depends on the seasonal cycle. The driving force
and mechanisms of seasonal changes are related to variations in the
physical, chemical and biotic environment, e.g. changes in solar radiation
and nutrient levels. However, in tropical latitudes, the seasonal succession of
phytoplankton species is not as obvious as in temperate latitudes (Harris,
1986). It might be supposed that the growth of phytoplankton in tropical
latitudes depends on ambient nutrient levels more than on other
environmental factors (Morris, 1980). Minimal seasonal variation in day length
and heat income does not prevent remarkable phytoplankton seasonal
cycles in the tropics, where the fluctuations in phytoplankton biomass and
composition are often related mainly to changes in hydrological and
hydrographical conditions, including variations in water level in lakes (Ibanez,
1998; Train & Rodrigues, 1998).
On comparing the three selected panchayats of the study area, the
greatest diversity of phytoplankton observed was from the Kainakari
panchayat, which is the lower most region (- 3 m blow MSL) of Kuttanad
wetlands, where Pamba River joins with Vembanad Lake. A total of 244800,
119500 and 94700 numbers per litre (Nos/L) of phytoplanktons were
encountered from Kainakari, Edathuva and Ala panchayat respectively
(graph 08 and 09). Most dominant class of phytoplankton observed form Ala
and Kainakari were Chlorophyceae with 14 and 49 species respectively, while
the dominant plankton observed from Edathuva was Bacillariophyceae with
14 species. Most dominant phytoplankton species observed from Ala
panchayat was Kirchneriella lunaris (6800 No/L) belonging to Chlorophyceae,
while from Edathuva was Gonatozygon spp. (6500 No/L) belonging to
Bacillariophyceae and from Kainakari was Melosira granulata (6800 No/L)
belonging to Bacillariophyceae. The least diversified class observed from the
three panchayat was Dinophyceae with two genera, namely Gymnodinium
and Peridinium, of which Gymnodinium spp. observed only from Ala
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panchayat. Peridinium tetras observed from all the three panchayats while
Peridinium cinctum was observed from only Edathuva and Kainakari
panchayats.
Many species of freshwater algae may proliferate quite intensively in
eutrophic (i.e. nutrient-rich) waters. However, they do not form dense surface
scums or “blooms,” as do some cyanobacteria. Most adverse health impacts
from recreational use of fresh waters have been associated with
Cyanobacteria rather than with freshwater algae (Reynolds, 1987).
Phytoplankton distributed throughout the water bodies and some groups can
change their positions within their environment in a variety of ways.
Cyanophyceae have worldwide distribution and a majority of species are
cosmopolitan. They are good photosynthesizers and replenish the water with
oxygen. Certain species of this group in freshwater fix atmospheric nitrogen to
supplement with nitrogen requirement (e.g. Anabaena and Nostoc), and
thus, have potential value as bio-fertilizer (Kapoor and Arora, 2000). In the
present study there were 10 species of Cyanophyceae observed form
Kainakari Panchayat, 4 species from Edathuva panchayat while members of
this group were absent in the Ala panchayat during the study period. The
most abundant Cyanophyceaean species observed from both Kainakari and
Edathuva was Oscillatoria limnetica with an average count of 5300 Nos/L. The
presence of Oscillatoria and Merismopedia indicate the beginning of
eutrophication of the water bodies (Ganai et al., 2010).
Euglenoids are almost unicellular, lack a distinct cell wall and possess
one, two or three flagella, they are generally abundant in water rich in
organic matter (Wetzel and Liken, 1991). In present study, Euglenophyceae
formed the least represented group of phytoplankton and observed only in
Edathuva and Ala panchayats, where phosphate, nitrate nutrients were
comparatively higher and salinity is comparatively lower than in Kainakari
panchayat. Euglena acus is the Euglenophycean member which represented
in both Edathuva and Ala panchayat with an average count of 3200 and
4200 Nos/L respectively. Species such as Chodatella subsalsa, Selenastrum
gracile, Spirogyra spp. (Chlorophyceae), Diatoma vulgare, Synedra ulna
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(Bacillariophyceae) and Peridinium tetras (Dinophyceae) were observed
frequently from all the three panchayat of the Kuttanad wetlands.
Some phytoplankton elements such as Arthrodesmus gibberulus,
Chodatella subsalsa, Diatoma vulgare, Euglena acus, Peridinium tetras,
Selenastrum gracile, Spirogyra spp. and Synedra ulna were observed
commonly from both Ala and Edathuva panchayats, while the species such
as Chodatella subsalsa, Diatoma vulgare, Kirchneriella lunaris, Nitzschia
palea, Peridinium tetras, Pinnularia nobilis, Selenastrum gracile, Staurastrum
longipes, Staurastrum sexangulare, Spirogyra spp., Synedra ulna and
Xanthidium perrisacanthum were observed from both Ala and Kainakari
Panchayats. The species observed commonly from both Edathuva and
Kainakari were Chodatella subsalsa, Coelosphaerium dubium, Cosmarium
subtumidum, Diatoma vulgare, Gyrosigma spp., Melosira granulata, Navicula
spp., Oscillatoria limnetica, Pediastrum duplex, Peridinium cinctum, Peridinium
tetras, Scenedesmus dimorphus, Selenastrum gracile, Spirogyra spp., Synedra
acus and Synedra ulna. Distribution of phytoplankton elements in the three
panchayats are given in table 36.
In estuaries, phosphate is introduced by tidal mixing from marine waters
and recycled (Smayda, 1983). According to Nalewajko and Lean (1980),
phosphate inputs do not balance algal uptake during phytoplankton blooms
and concentrations decrease. In the present study, phosphate appears to
represent the nutrient most closely associated with temporal variability in
phytoplankton. Although there are no experimental data to support this
hypothesis, the analysis suggests that phosphate and chloride concentrations
were positively influenced by the phytoplankton distribution, while nitrate,
sodium and potassium concentrations were much less affected.
A significant variation has been noted in class wise and species wise
distribution of phytoplankton in the three study locations of Kuttanad
wetlands. The temperature of the water samples is on an average of 28 0C
and the water medium are slightly acidic in character. Turbidity range (5.71 to
11.59 NTU) showed that water is moderately transparent. All other quality
parameters were within desirable limit. However, a significant and gradual
increase in salinity has been noted from upper Ala (0.037%) to middle
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Edathuva (0,070%) and from there to lower Kainakari (0.167%), whereas a
gradual reduction was observed in hardness, calcium and magnesium from
Ala to Edathuva and to Kainakari panchayats. Phytoplankton diversity was
found to be higher in the water samples collected form Kainakari panchayat
located in the downstream of Pamba river basin. The reason can be
attributed to the lentic nature of aquatic system together with the availability
of nutrients in optimum quantity favoring maximum growth. Harilal (2005)
made similar observation from Karamana and Kallayi rivers of Kerala. The
results also indicated the positive dependence of salinity and negative
dependence of hardness of the phytoplankton population. A gradual
increase in the total count of phytoplankton observed from Ala to Edathuva
and from Edathuva to Kainakari. Total count of phytoplankton from Ala,
Edathuva and Kainakari was 94700 No/L, 119500 No/L and 244800 No/L
respectively (Table 37). A gradual reduction in the total count of class
Bacillariophyceae and Dinophyceae has also been observed in the study
period. The average concentration of water quality parameters and
quantitative analysis of phytoplankton are given in the table 38.
Table 36. Distribution of phytoplanktons in the three panchayats
Class Scientific Name Kainakari Edathuva Ala
1
Cyanophyceae
Aphanotheca saxicola × √ ×
2 Agmellum quadriduplicatum √ × ×
3 Anacystis cyanea √ × ×
4 Aphanocapsa benaresnsis √ × ×
5 Aphanothece pallida √ × ×
6 Botryococcus protuberans × √ ×
7 Coelosphaerium dubium √ √ ×
8 Gloeothece linearis √ × ×
9 Gomphosphaeria aponina √ × ×
10 Merismopedia glauca √ × ×
11 Oscillatoria limnetica √ √ ×
12 Spirulina sp. √ × ×
13
Chlorophyceae
Actinotaenium globosum √ × ×
14 Ankistrodesmus falcatus √ × ×
15 Ankistrodesmus spiralis × √ ×
16 Arthrodesmus gibberulus × √ √
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17 Bambusina sp. √ × ×
18 Chlamydomonas spp. √ × ×
19 Chlorella vulgaris √ × ×
20 Chodatella subsala √ √ √
21 Closteriopsis longissima × √ ×
22 Closterium graute √ × ×
23 Closterium kuetzingii √ × ×
24 Closterium lineatum √ × ×
25 Coelastrum sp. × × √
26 Cosmarium clepsydra √ × ×
27 Cosmarium contractum √ × ×
28 Cosmarium decoratum √ × ×
29 Cosmarium lundellii √ × ×
30 Cosmarium subtumidum √ √ ×
31 Cosmarium viridis × × √
32 Desmidium baileyi √ × ×
33 Desmidium grevillei √ × ×
34 Dictyosphaerium pulchellum √ × ×
35 Dimorphococcus lunatus √ × ×
36 Gonatozygon monotaenium √ × ×
37 Hyalotheca dissiliensis √ × ×
38 Kirchineriella subsolitaria × √ ×
39 Kirchneriella lunaris √ × √
40 Micrasterias alata × √ ×
41 Micrasterias foliaceae √ × ×
42 Micrasterias lux √ × ×
43 Micrasterias radiata √ × ×
44 Micrasterias truncata × × √
45 Mougeotia sp. √ × ×
46 Onychonema laeve √ × ×
47 Oocystis elliptica √ × ×
48 Palmella mucosa × × √
49 Pediastrum duplex √ √ ×
50 Pleudorina sp. √ × ×
51 Scenedesmus arcuatus √ × ×
52 Scenedesmus dimorphus √ √ ×
53 Scenedesmus quadricauda √ × ×
54 Schroederia spp. × × √
55 Selenastrum gracile √ √ √
56 Spirogyra sp. √ √ √
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57 Spondylosium nitens √ × ×
58 Staurastrum arctiscon √ × ×
59 Staurastrum curvatus √ × ×
60 Staurastrum freemanii √ × ×
61 Staurastrum longipes √ × √
62 Staurastrum paradoxum × × √
63 Staurastrum setigerum × × ×
64 Staurastrum sexangulare √ × ×
65 Staurodesmus convergens √ × √
66 Staurodesmus corniculatus √ × ×
67 Staurodesmus glaber √ × ×
68 Tetraedron sp. × √ ×
69 Westella botryoides √ × ×
70 Xanthidium bengalicum √ × ×
71 Xanthidium hastiferum √ × ×
72 Xanthidium perrisacanthum √ × √
73 Xanthidium sp. √ × ×
74
Bacillariophyceae
Asterionella Formosa × × √
75 Achnathes inflata √ × ×
76 Anomoneis spp. × √ ×
77 Asterionella gracillima √ × ×
78 Aulacoseira granulata × √ ×
79 Cocconeis littoralis × √ ×
80 Cyclotella stelligera √ × ×
81 Cymbella prostrata × × √
82 Diatoma vulgare √ √ √
83 Fragillaria crotonensis × √ ×
84 Fragillaria intermedia × √ ×
85 Fragillaria capucina √ × ×
86 Fragillaria virescens √ × ×
87 Gomphonema spp. × √ ×
88 Gyrosigma spp. √ √ ×
89 Melosira granulata √ √ ×
90 Melosira varians × √ ×
91 Navicula sp. √ √ ×
92 Nitzschia palea √ × √
93 Pinnularia nobilis √ × √
94 Rhizosolenia setigera × √ ×
95 Stauroneis anceps √ × ×
96 Stephanodiscus hantzschii × × √
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97 Surirella robusta √ × ×
98 Synedra acus √ √ ×
99 Synedra ulna √ √ √
100 Tabellaria fenestrata √ × ×
101 Tabellaria flocculosa × × √
102
Euglenophyceae
Euglena acus × √ √
103 Phacus tortus × × √
104 Phacus acuminatus × √ ×
105 Phacus longicauda × √ ×
106
Dinophyceae
Gymnodinium sp. × × √
107 Peridinium cinctum √ √
108 Peridinium tetras √ √ √
109 Chrysophyceae Dinobryon sertularia √ × ×
Table 37. Total count of different classes of Phytoplanktons
Kainakari Edathuva Ala
Cyanophyceae 35800 13000 Nil
Chlorophyceae 139500 34400 52900
Bacillariophyceae 61000 56900 26000
Chrysophyceae 3400 Nil Nil
Euglenophyceae Nil 8600 8000
Dinophyceae 5100 6600 7800
Table 38. Comparative analysis of average water quality and planktons
Kainakari Edathuva Ala
Temperature (oC) 28.383 28.104 28.212
pH 6.554 6.23 6.139
Conductivity 54.166 162.166 95.708
Turbidity (NTU) 5.71 8.508 11.595
Salinity (%) 0.167 0.070 0.037
DO (mg/L) 5.528 6.337 6.304
CO2 (mg/L) 20.91 21.833 23.070
Acidity (mg/L) 21.083 27.916 24.166
Alkalinity (mg/L) 76 41.458 50
Nitrate(mg/L) 0.064 5.880 6.693
Phosphate (mg/L) 0.155 0.016 0.024
Calcium (mg/L) 35.790 10.317 9.083
Magnesium (mg/L) 15.284 6.574 5.251
Hardness (mg/L) 58.133 27.333 17.5
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Chloride (mg/L) 56.912 42.369 20.387
Sodium (mg/L) 6.553 10.270 10.762
Potassium (mg/L) 1.686 3.941 3.545
Cyanophyceae (Nos/L) 35800 13000 0
Chlorophyceae (Nos/L) 139500 34400 52900
Bacillariophyceae (Nos/L) 61000 56900 26000
Chrysophyceae (Nos/L) 3400 0 0
Euglenophyceae (Nos/L) 0 8600 8000
Dinophyceae (Nos/L) 5100 6600 7800
Total phytoplankton count (Nos/L) 244800 119500 94700
Total zooplankton count (Units/L) 256 81 35
6.3.3. Diversity and distribution of zooplankton
Zooplankton is a major group in the energy transfer at secondary level
and plays an important role in the secondary production of wetlands. Long-
term variability of zooplankton is significant to differentiate whether these
fluctuations are due to natural causes or due to man made changes. Sharma
and Wilma (2007) studied about abundance of zooplankton in relation to
petroleum hydrocarbon content along the Kollam coast and recorded
maximum zooplankton count of 1390 No/m3 from the Paravoor coast. Madhu
et al. made a detailed analysis on Monsoonal impact on planktonic standing
stock and abundance in a tropical estuary (Cochin backwaters-India) and
detected a strong seasonal impact on zooplankton biomass. Detailed studies
zooplankters in Kuttanad wetland areas are lacking.
In the present investigation zooplankton population was found to be
very low in the study area and this can be attributed to the low abundance
of phytoplankton. The diversity of phytoplankton is of primary importance in
producing the diversity of zooplankton (Das, 1991). The major groups of
zooplankton observed were Nauplius followed by Rotifers, Copepods and
Cladocerans. Rotifers were represented by Brachionus sp., Monostyla sp.,
Polyarthra multiappendicula, Lecane luma and Keratella sp. Nauplius and
Rotifers were dominant during the study season. Dominant group of
zooplankton observed from the three panchayats were Nauplis, Copepods
and Cladocerans.
Maximum number of zooplankton observed from the water bodies of
Kainakari panchayat with 256 units/L followed by Edathuva (81 Units/L) and
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then Ala panchayats (35 Units/L). A significant gradual increase could be
noted in all kinds of zooplankton from upper Ala to middle Edathuva and then
to Kainakari panchayat. 150 Unit/L of Nauplius could be counted from the
water samples of Kainakari panchayat while the count was 46 and 16 Units/L
in Edathuva and Ala panchayats respectively (graph 10 and 11). Copepods
population also showed much variation from Ala to Kainakari panchayat
during study period. Rotifer members namely Monostyla sp. and Polyartha
multiappendiculata were frequently observed from the three panchayat of
the Kuttanad wetlands. A rotifer member namely Brachionus sp. observed
from both Edathuva and Kainakari panchayat but not from Ala panchayat.
Keratella sp. observed only from Ala panchayat while Lecane luma observed
only from Kainakari panchayat, both are the members of Rotifera (table. 32).
Zooplankton population is regulated by both top-down (predation) and
bottom-up (food supply) control. Predation of zooplankton may be a key
determinant of zooplankton seasonal succession (Gliwicz and Pijanowska,
1989). Depending upon the phytoplankton biomass, the zooplankton
population also changes. Various workers have demonstrated a statistical
relationship between the primary producers (phytoplankton) and the main
herbivore (zooplankton) population in various systems. The highest
zooplankton count was noted in monsoon period and it has been shown that
phytoplankton was also found maximum in the same season. Correlation
studies also showed a positive relationship between these two parameters.
McCauley and Kalff (1981) also found a clear correlation between
phytoplankton and zooplankton. In the present investigation also
phytoplankton count varied along with zooplankton count. Zooplankton also
correlated with the nutrient status such as nitrate and phosphate of the study
area.
A positive correlation was obtained between zooplankton and
temperature. Patalas (1972) reported more zooplankton at increased
temperature. Various workers studied relationship between temperature and
Rotifers. Balkhi et al. (1984) found rotifers in water where the temperature was
as low as 50C while Sharma and Srivasthava (1986) recorded rotifers at
temperature as high as 350C. The positive correlation obtained between
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rotifers and temperature during the present study suggests that rotifers prefer
water with high temperature. The Cladoceran population was found to be
scanty in Kuttanad wetlands.
During pre-summer monsoon, high saline waters prevailed over the
estuary due to the incursion of Arabian Sea waters and the lower reaches of
Kuttanad wetlands and salinity becomes slightly higher (Madhupratap, 1987).
However, in the upper reaches, freshwater influx of Pamba River results in low
saline waters. Therefore, a marked salinity gradient was present between
upper and lower reaches of Kuttanad wetland. High saline stations always
formed a single cluster indicating that the zooplankton abundance in the
system is controlled by salinity. Salinity is reported to play a major role in
controlling the distribution of zooplankton in estuaries (Godhantaraman, 1994;
Sujatha and Panigrahy, 1999). Influence of lower salinity on the distribution of
mesozooplankton in Cochin backwater is also well established (Madhupratap
and Haridas, 1975). Preponderance of diatoms in nutrient enriched
environments is noticed many years back (Menzel et al. 1963, Qasim et al.,
1973) and in such conditions dinoflagellates fail to dominate. Dinoflagellates
are known to be „slow growers‟ which are more adapted to oligotrophic
(stratified) waters (Cushing, 1989).
Microzooplankton (20 - 200μm) constitutes a considerable portion of
the zooplankton biomass in marine and estuarine environments (Porter et al.,
1985; Pierce and Turner, 1992). Consequently, there has been an upsurge of
scientific interest on microzooplankton (MZP) worldwide. The biological
production (primary and secondary) becomes intense at low salinities (5-8)
because of their preference to a variety of planktonic organisms (marine,
brackish and fresh water) at low salinity. Hence, the estuaries are always
considered as biologically active zones (Kibirige and Perissinotto, 2003).
Among mesozooplankton, copepods formed the dominant group
(Madhupratap, 1979), with strong seasonality in accordance with the
changes in salinity (Pillai et al., 1973; Madhupratap, 1987). In contrast, some
earlier investigations did not find any relationship between the residence time
of the water, the depth of light penetration and the biomass of the
phytoplankton, which is the most important food-source for the zooplankton
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(Chetelat & Pick, 2006). As the Vembanad water channels in Kainakari down
into the side arms, its speed and the amount of suspended matter decreases,
while the depth of light penetration increases. As a consequence, the
biomass of the phytoplankton increases, providing better food-supply for the
local zooplankton assemblages. High concentration of primary food generally
results in the swarming of a few herbivores/omnivores such as copepods and
amphipods (Goswami and Shrivastava, 1996). Large and expansive water
channels facilitate the growth of greater number of phytoplankton, which in
turn support the zooplankton groups.
6.3.4. Diversity and distribution of butterflies
Butterflies have been regulated as a symbol of beauty and grace
(Khan et al., 2003). These marvelous creatures are found in almost every part
of the world except snow bound areas like Antartica (Rafi et al., 2000). The
present study unveiled a significant assemblage of butterflies including 22
species from Nymphalidae, 10 species from Papilionidae 5 species from
Pieridae and 3 species each from Lycaenidae and hesperidae. The overall
analysis of primary data revealed that Nymphalidae form the major
component contributing significantly 51.16% of total, followed by
Papilionideae (23.25%), Pieridae 11.62%), Lycaenidae (6.97%) and Hesperidae
(6.97%.
A considerable number of butterflies were found during the rice
cultivation season in Kainakari and Edathuva panchayat and a significant
reduction have been noted during the flooded season just after harvesting.
Comparatively higher population of butterflies was noted frequently during
the entire season in Ala panchayat, where expansive paddy fields are not
common. Jorge et al. (2000) reported that the number of Lycaenidae is
common in cultivated fields, dump grass lands, marshes and slow flowing river
banks. These low flying lepidopterans are among the commonest and wide
spread (Goodden, 1977). In the present study two species of Lycaenidae,
namely Castalius rosimon and Jamides celeno are observed in almost all
homesteads and river banks. Nymphalidae and Papilionidedae showed a
cosmopolitan distribution in all over the three panchayat locations. Five
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species of butterflies belonging to Pieridae were often found in all the three
panchayat areas. Two species, namely Tagiades litigiosa and Borbo cinnara
were not observed anywhere from the Kainakari panchayat while a few
numbers of these species were observed from Edathuva and Ala panchayats.
The present investigation made an attempt to study the ecosystem
influence and distribution of butterflies in the wetland area of Kuttanad
ecosystem. The field observations has revealed the presence of 22 species
under Nymphalidae family as the most dominant group and distributed all
over the Kuttanad wetland systems. The overall interpretation of the result
indicated towards the significance of rice fields as potential habitats for a
diverse array of butterflies. Similar results have been found from the study of
Bahaar and Bhat (2011) while studying the community organization and
distribution of Lepidoptera in the rice fields of Kashmir. Among the three study
locations, Ala panchayat (upper Kuttanad) showed greatest collection of
butterflies belonging to all observed families indicate the substantial
dependence of these flies with luxuriant shrub and tree vegetation.
Distribution of butterfly population in the three study panchayat is shown in
table 33.
6.3.5. Diversity and distribution of fishes
Vembanad Fish Count 2009 identified 65 species of fin fishes and 14
species of shell fishes from the Vembanad backwaters (ATREE, 2009). Of the
three selected panchayats, fish population is dominant in Kainakari
panchayat, and the area receives maximum sunlight than the other two
panchayats (Table 34). It has been reported that over the last 30 years, the
fish diversity has reduced from 150 species to 36 species and many are
reported as critically endangered or even extinct in the region (Padmakumar
et al., 1988).
Out of 61 species observed, 73.7% (45 species) are native 21.3% (13
species) are endemic and 4.9% (3 species) are introduced for cultivation. The
introduced species noted from the area are Cirrhinus mrigala,
Ctenopharyngodon idella and Oreochromis mossambicus. Based on IUCN
threatened species (2009), 6 species namely Carinotetraodon travancoricus,
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Labeo dussumieri, Ompok malabaricus, Batasio travancori, Clarias dussumieri
and Horabagrus brachysoma are noted as endangered ones, 5 species
namely Anabas testudineus, Heteropneustes fossilis, Mystus montanus and
Puntius sarana are noted as vulnerable and one species namely Xenentodon
cancilla is noted as risk/near threatened species.
6.3.6. Diversity and distribution of birds
Vast areas of paddy fields and expansive water bodies in the Kuttanad
wetlands provide suitable habitats for many migratory species. Terns, sea
gulls, sandpipers, plovers, teals, etc., are some of the important avian visitors.
Neelakandan (1996) listed out 483 species of birds from entire Kerala, of which
226 species (47%) were reported from Kuttanad wetland itself by Narayanan
et al. (2011). A bird count in 2007-08 listed 27942 birds belonging to 56 wetland
and wetland associated bird species (Sreekumar, 2008). The kayal is home to
the third largest population of more than 20,000 waterfowls that visit India
during winter. Endangered waterfowls that have been identified from the
region are spotbilled pelican, oriental darter, water cock and black billed turn
(Anil Kumar, 2012). Present investigation is restricted to only three panchayats
of the Kuttanad wetlands which are located along line of the Pamba River
basin. Fifty seven species of birds comprising 26 families are recorded from
three panchayat namely Ala, Edathuva and Kainakari during the study
period (2008-2012). Of which 83.6% are noted as resident birds, 10.9% are
migratory and 5.4% are local migratory species. The avian families observed
from the study area were Anatidae, Rallidae, Alaudidae, Capitonidae,
Cerylidae, Charadriidae, Ciconiidae, Motacillidae, Muscicapideae,
Nectaridiidae and Sturnidae. Anatidae possess most diversified family
comprising 6 species followed by Rallidae with 5 species. Detailed analysis
revealed that 67.2% belongs to non-wetland category and 32.7% belongs to
wetland or wetland depended category.
In the Kuttanad wetland greater number of migratory birds is found on
the large paddy fields just after the rice harvesting. Their occurrence
coincides with availability of food which can easily probing into the mud.
Common group of migratory taxa found in the area belongs to Anatidae
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family. Largest number of wetland and migratory birds found in Kainakari
panchayat due to the presence of expansive paddy fields on compared with
the other two areas. Maximum species diversity occurred in Ala panchayat
comprising 50 species, followed by Edathuva (47 species) and Kainakari (46
species). Distribution status of bird population in the three study panchayat
with respect to its ecological status is shown in table 35. While wetland
dependent bird species are dominated in Kainakari. It clearly indicates that
the land birds mostly preferred in the upper areas of Kuttanad wetlands. This
may be due to fewer disturbances, higher water retention for a longer period,
availability of abundant food and more vegetation. Narayanan et al., (2011)
reported that most of the wetland birds were seen at the eastern boundaries
of the Kuttanad. This report is evident from the present study. Six migratory
species observed in the study area are Anas acuta, Anas crecca crecca,
Anas querquedula, Aythya nyroca, Oriolus oriolus kundoo and Porzana pusilla
pusilla. Local migratory species noted are Anas poecilorhyncha, Anhinga rufa
melanogaster and Mycteria leucocephala. All other ornithofauanl
component noted in the area was resident species.
All identified migratory birds were frequently observed from Kainakari
panchayat whereas 5 of them are often observed from Edathuva and only 2
species from Ala. Representative species of all 26 families were observed from
Ala while representatives of 24 families and 22 families were observed from
Kainakari and Edathuva respectively. Acridotheres tristis tristis, Apus affinis,
Centropus sinensis parroti, Columba livia intermedia, Corvus Macrorhynchos
culminates, Corvus splendens protegatus, Eudynamys scolapacea
scolapacea and Passer domesticus indicus are resident non-wetland birds,
(plate 25) and Amaurornis phoenicurus phoenicurus, Alcedo atthis
taprobana, Ardeola grayii grayii , Bubulcus ibis coromandus, Gallinula
cloropus indica, Mycteria leucocephala and Porphyrio porphyrio
poliocephalus were the common resident or local migrant wetland
dependant species frequently found throughout the study area (plate 24).
Porzana pusilla pusilla and Anas crecca crecca were two migrant birds
observed in all the three panchayat during the study period. Anas acuta and
Aythya nyroca are two migratory species observed both from Edathuva and
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Kainakari panchayat. Local migrant species such as Anas poecilorhyncha
poecilorhyncha, Anhinga rufa melanogaster and Mycteria leucocephala
could be observed from the three panchayats of the study area. The species
such as Anhinga rufa melanogaster, Aythya nyroca and Mycteria
leucocephala are listed as near threatened category (IUCN, 2010).
Wetlands in India, as elsewhere, are facing tremendous anthropogenic
pressures (Prasad et al., 2002), which can greatly influence the structure of
bird community (Kler, 2002; Verma et al., 2004; Reginald et al., 2007). Siltation,
pollution and weed infestation are the major threats to the avifauna (Ishwara
Bhat et al., 2009). Presence of people and domestic animals can make
wetlands unacceptable to waterfowl. Major human disturbances to wetlands
bird habitat include the use of motor vehicles and other machines, including
motorboats, in or adjacent to wetlands; spring burning or cultivation of open
lands near water; hunting; and drainage, dumping or other destruction of
wetlands.
The loss of habitat through direct and indirect anthropogenic activities
causes immense threat to the birds especially the migratory birds of Kuttanad.
Water Hyacinth (Eichhornia crassipes) has rapidly covered the water surface
especially in the Kainakari panchayat reducing the feeding areas for water
birds. All possible threats of ornithofaunal population in Kuttanad wetlands
and their conservation measures are elaborated in the study of Narayanan et
al., (2011). According to their study major threats of wetland birds in Kuttanad
wetland ecosystem are landscape alteration, hunting overgrowth of exotic
vegetation, pesticide from agricultural field, felling of nesting and roosting
trees and tourism. It is obvious to understand that conservation and
management efforts have focused on legal protection, habitat
management, population management, and human dimensions, and all
must be used concurrently to be effective. Our focus here is habitat
management, which has been used for different purposes but is often aimed
at species management when, at least for wetlands, most management
influences the entire community.
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6.4. ANALYSIS OF LIVELIHOOD RESOURCE DATA
6.4.1. Livelihood in General
Agriculture is the primary source of income generation of the three
panchayats. With extensive paddy fields, the existing agricultural practices in
the three study panchayats are dominated by paddy cultivation followed by
coconut. Fruit trees like mango, jack-fruit, tamarind and tuber crops like
tapioca, Amorphophallus, Colocasia and plantains are cultivated in the
elevated areas adjoining the paddy fields and also in the homesteads. These
are also cultivated as intercrops in coconut plantations. Pepper is also
cultivated although rarely due to poor yield and its susceptibility to continuous
flooding in the area especially in Kainakari panchayat. Besides, other
vegetable crops ornamental plants are cultivated widely in the homesteads
of all the three panchayats.
Another major livelihood practice which is common to the Kainakari
and Edathuva panchayat is fishery, which is confined to only during rainy
seasons in Ala panchayat. The water bodies in Edathuva and Kainakari area
are nutrient rich and have optimum temperature and sunlight availability,
which offer favorable environment for the luxuriant growth of fishes, prawns
and other aquatic organisms. But due to the intense pollution and lack of
salinity intrusion, there is a considerable reduction in the fish wealth of the
area. Moreover, destruction caused due to heavy floods and the lack of
proper marketing facilities has made the fishermen dissatisfied with fishing.
Kerala is the top producer of lime shells in India. Although, occurrences
of lime shells are reported from almost all backwater systems of Kerala,
economically viable deposits are confined to the Vembanad Lake. Lime shell
is being mined from this lake since long (Rasalam and Sebastian, 1976). Two
types of shells are being extracted – the white shells and the black shells. The
white shells are sub fossil clam shells inter-layered within the late Quaternary
deposits, whereas black shells are exoskeletons of living clam Villorita sp.,
which occur abundantly in shallow lake beds. These shells are commercially
dredged for cement industries and also harvested as a means of livelihood of
the people. Ravindran et al., (2006) reported annual production of 30,000-
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40,000 tonnes of black clam and 7000 tones of shell fish from the region. They
calculated that approximately 20,000 fishermen are directly or indirectly
involved in the exploration of aquatic resources with an annual revenue of Rs.
100 million. Shell mining of black shell is an important occupation of the
Kainakari panchayat, which does not occur in Edathuva and Ala
panchayats. Two inland lakes situated as a part of Vembanad Lake in the
Kainakari panchayat forms the prime location of shell in the area. The shell
occurs 1-1.5 meter deep in the clayey soil in lakes. The shell forms the
important source of calcium oxide, silicon dioxide and manganese oxide.
Many industries based on this resource are established in the State and.
Optimum salinity is important for the growth of shells, but the changes in the
level of salinity that have occurred has affected their growth.
There are several other means of livelihood and which are common in
all the three panchayats such as community, social and personal services;
mining and quarrying; real estate; post and telecommunication; health and
social work; educational services; public administration and national defense;
wholesale and retail trade; utilities supply and other activities.
6.4.2. Sustainable Agriculture
With paddy cultivation as the dominant agricultural activity, its
sustainability is paramount with modern tools, scientific and technical
knowledge and there is abundant scope for increasing paddy production.
Adding to paddy are coconut and an array of tree and agricultural
crops like mango, plantain and vegetables together providing new scopes
for introducing sustainable agriculture in the area, which with small
homesteads, is viable options.
Kuttanad area being below sea level including the three panchayats in
the study area has received much attention for sustainable agriculture
practices, which include integrated agriculture, modern mechanization,
intercropping and mixed cropping both at home and farm levels particularly
with regard to major crop like paddy and coconut. Some medicinal and
spices like pepper and nutmeg which together offered opportunities for the
156 | P a g e
sustainability in the agricultural produce and livelihood issues. Bund cultivation
of agricultural crops also contributes to the above situation.
In Kuttanad, double cropping of rice may not always be feasible due to
floods during the monsoon and this combined with low returns from rice
cultivation due to the high cost of land lease and labour has tempted the
farmers to abandon one crop of rice and instead culture fish and/ or prawn
during the season, leading to increased benefits. The ideal season for rearing
fish and prawns in the rice fields of Kuttanad appears to be March to
October. This arrangement also reduces the production cost of rice since the
soil is soft and clean, after the fish/ prawn harvest and allows immediate
seeding and transplanting. Prawn filtration in the adjoining rice fields of
backwaters is a unique feature of the inland fisheries of Kerala. An inland
water channel based fish farming model existed in the Kuttanad wetland has
been depicted in figure 01.
6.4.3. Agroforestry
An area which has not received focus of attention is agroforestry, which
will give a new dimension to the Kuttanad area as a whole and the study
panchayats in particular. It has been noticed that the whole wetland system
is poor in tree wealth which has affected not only economic gains but also as
an impact on environmental conditions particularly with reference to climate
change. The increased tree wealth will increase the green cover of the leaf/
canopy which will absorb more CO2 and other trace gases and emit O2
which in turn has an amelioraating effect of the climate change problem in
which the area is vulnerable.
The survey and study of the selected panchayats revealed the nature
of existing agroforestry practices and typical models, which throw light on the
scope of developing sustainable agroforestry packages in these wetland
areas. A unique feature of the existing agroforestry pattern in the lowland
zone is the traditional practice of pisciculture in ponds within homesteads.
Pisciculture in such ponds of area ranging from 5 to 10 cents in home garden,
are promising income generating activity that helps utilize the advantages of
natural resources in a sustainable manner. Similarly the abundant growth of
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the different varieties of Nymphaea and Nelumbo, which are of high
horticultural value in, ponds and other small water bodies (including
abandoned paddy fields) characteristic of the area offer great scope in
projecting aqua-floriculture as an ecologically compatible and economically
viable agroforestry operation for the lower Kuttanad areas (Kainakari
panchayat). Home gardens of middle Kuttanad (Edathuva panchayat) and
upper Kuttanad (Ala panchayat) areas possess an assortment of fruit crops,
medicinal plants, timber plants and other plants of economic importance, of
which timber yielding fruit trees are dominant owing to its multipurpose utility.
Typical home garden models of these areas possess optimum plant resources
with effective land utilization and having a direct bearing on economic
sustainability.
In Kuttanad area natural agroforestry practices have been observed,
which do not as such occur in the three panchayats studied. However, the
feasibility of introducing agroforestry practices in the three panchayats and
connected areas of Kuttanad are high. Based on the physiographic pattern
of the three panchayats agroforestry practices need to be appropriately
planned and implemented, and model proposals are presented in figure 02
to 06.
Considering the three panchayat models agroforestry proposal ought
to be designed for Kainakari panchayat in such a way that it conforms with
small level holdings in all of which there has to be provision for a modest
house for living surrounded inevitability by coconut and even a pond for
fishing (figure 02). There can be various combinations of vegetable crops like
plantain, Moringa and Carica papaya together with a few tree elements
(Garcinia gummi-gutta) of medicinal and timber (Artocarpus heterophyllus)
value. However, there can be various combinations of lesser utilized fruit crops
or even floriculture plants as per the aesthetic desire of the residents and
conforming with the land availability. Kainakari is typically a rural setup and
the various land holders put together can bring about considerable rural
development under the guidance and support of concerned panchayats.
The panchayat Edathuva was a mixture of small holdings and medium
holdings more or less similar to that of Kainakari (figure 03 and 04). This
FIGURE 02: HOMESTEAD AGROFORESTRY MODEL FOR LOWER KUTTANAD (KAINAKARI PANCHAYAT)
Cn: Cocos nucifera Ce: Colocasia esculentaMpa: Musa paradisiacaMp: Moringa pterygospermaMi: Mangifera indicaTp : Thespesia populneaHr: Hibiscus Hr: Hibiscus rosa-sinensisAct: Areca catechuAh: Artocarpus heterophyllusAo: Anacardium occidentaleAe: Ailanthus excelsaCp: Carica papayaPg: Psidium guajavaGg: GaGg: Garcinia gummi-guttaMk : Murraya koenigiiVz: Vetiveria zizanioidesSma: Swietenia macrophyllaPd: PondH: House
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panchayat has a slight influence of the urban culture as detected by tourists
and worshipers coming to the Edathuva church and there is a proliferation of
housing structures. However, this also remain a rural setup in general and
therefore a planned approach in developing agroforestry and to be
engaged in other occupations like fish farming could be in support of the
overall development of the rural system.
The Ala panchayat is vast in available area for development and
marked also by the influence of the nearby township of Chengannur and of
the continued flow of people living all over the place. The land holding
include large size of one acre and above (figure 05) and also medium and
even small holdings and thus the panchayat area is of mixed land holding.
Accordingly there is a scope for plantation development of which the rubber
found a place. Taking the entire panchayat together the land area has a
common presence of coconut particularly around the large or smaller houses
and also wherever open lands are available. There are a large number of
institutions found in the panchayat, the land holdings of which are planted
with mango and other trees like tamarind. The residential houses with medium
level holdings (figure 06) can hold mixed cropping of various combinations of
economic/agroforestry related plants which will bring about a viable
opportunity for green belting.
Although the area is influenced by urbanization, it still remains a rural
setup in which all the three panchayat taken together can evolve rural
development models in the homsteads, bunds (figure 07) and all other open
places wherever possible. The all round selection of lesser utilized plant
resources/economically viable medicinal plants and resource of conservation
value (Bacopa monnieri) can be promoted for cultivation. Apart from the
scientific programmes opinion from the local peoples and farmers have been
recorded for the sustainable management of agriculture, and presented here
in Appendix 02.
Another area of sustainable development of food resources which should
recieve consideration is Integrated Farming System (IFS). Integrated farming
system has revolutionized conventional farming of livestock, aquaculture,
horticulture, agro-industry and allied activities (Chan, 2006). It could be crop-
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fish integration, livestock-fish integration, crop-fish-livestock integration with
combinations of crop, livestock, fish and other enterprises (Olele et al., 1999).
The benefits of IFS over those of traditional farming system (Ugwumba and
Orji, 2006), cannot be over emphasized. Though agricultural systems are
better practiced on large expanse of land, subsistence farmers notable for
their small holdings can equally engage in them, especially those involving
homestead fish ponds (Ugwumba, 2005). This is because IFS has been
confirmed to reduce cost of production and thus increase farmer‟s
productivity, income, nutrition and overall welfare (Tokrishna, 2006). Existing
integrated cropping practices in the Kuttanad wetlands are depicted in plate
32.
Culturally the cultivation of coconut is a homestead affair practiced in all
house holdings so also are some trees like Mangifera and Garcinia apart from
field crops like plantain and other vegetables crops. Similarly, the lower
income groups of people practice fish farming, duck farming and poultry
farming. As an occupation toddy tapping is also common in all the three
panchayats. All the proposed models when properly integrated and put into
practice will substantially produce greater results in terms of generation of
finance and environmental betterment. The hazards of climate change may
also to some extend lessened by increase in tree wealth.
The scope for effective rural development as presented in the agroforestry
models together with innovative models under the concept of integration of
agriculture, aquaculture, floriculture, silviculture and pastoral systems. Some
integrated agriculture practices suited for Kuttanad wetlands as a whole and
the study panchayats in particular are Aqua-silvo pastoral system, Aqua-flori
pisci-culture and Agro-silvo-pastoral system, which has been schematically
shown in figure 08, 09 and 10 respectively.
Integrated Agriculture-Aquaculture (IAA) systems is the integration of
aquaculture with fruit, rice, and livestock can help to improve the use made
of local natural resources and to increase the contribution of inland
aquaculture to total agricultural production in Kuttanad wetlands. In areas
where irrigation facilities are not available, a second crop of rice is possible by
constructing water storage areas within the field. Compared to many
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technologies, rice-fish culture is a low-risk technology. It demands little money,
is not particularly new for most rice farmers and involves few conflicts with
other farm activities. Rice-fish culture conserves water. Rice-fish culture saves
farmers time, allowing them to undertake income-generating activities or to
improve on existing ones. Rice yields are usually enhanced, although there is
great variation from farm to farm. Yields are very rarely adversely affected
when the farmer manages the system well. Apart from Integrated rice-fish
farming some other sustainable practices which are suited for the Kuttanad
wetlands are integrated grass-fish farming, integrated pig-grass-fish farming,
integrated fish-duck farming, integrated fish-horticulture and fodder-fish
integration.
6.5. ANALYSIS ON ENVIRONMENTAL IMPACTS
6.5.1. Seasonal/occasional flooding
Floods are a regular phenomenon during the monsoon period due to
the discharge of large quantities of river water into Kuttanad. As the north-east
monsoon recedes, the area is exposed to tidal incursion of saline water from
the Arabian Sea through the Kochi bar mouth, making the wetland ecosystem
predominantly saline. The Kuttanad agro system, therefore, is faced with serious
problems of hydrology, floods and salinity. Monsoon season brings with it the
perennial problem of floods, endangered by the region's four major rivers,
Pampa, Achenkovil, Manimala and Meenachil, which together drain the
water into the Vembanad Lake and empty into the Arabian Sea through the
Cochin estuary.
The entire study area is prone to flood. During rainy season, floods are
usual in the entire lowland region and so rice cultivation is possible only once
a year. Floods often damage the bunds causing submergence of the paddy
fields and loss of crops. So, cultivation is limited to only one crop per year at
many places in the area (IIRDS, 1978). Agriculture in the area is mainly
dependent on weather conditions and therefore unexpected rainfall and
flooding cause destruction of crops. As a measure to reduce the hazardous
effects of floods, the outer and inner margins of the paddy field should be
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strengthened by constructing stone walls, which is a common practice of the
area (Alexander et al., 2010). Selected views of hardship of occasional
flooding in Kuttanad wetland systems are shown in the plate 33.
6.5.2. Sacred grove degradation
Sacred forest being possibly remnants of natural vegetation needs
special efforts in conservation. Considering the three study panchayats in
Alappuzha district, Kainakari panchayat holds three minor sacred groves
associated with homesteads and are protected by the local people. In Ala
panchayat there are two major sacred groves of about 30 cents each
associated with temples and three minor sacred groves associated with
homesteads, whereas in Edathuva panchayat there are no sacred groves.
Major threats in the existence of sacred groves in the area are the brake up
of ancestral joint family systems to nuclear families and partition of family
properties along with the changing socio-economic scenario.
Weakening of beliefs, faiths and taboos associated with these groves
has added the intensity of its destruction. Due to the disappearance of
traditional belief systems sacred groves and their structures are now
considered mere superstitions. Profuse regeneration of exotic invasive species
such as Lantana camera, Chromolaena odorata, Acacia auriculiformis,
Leucaena leucocephala, etc. hamper the native species of groves, which
also contribute to the destruction of the sacred groves.
The state of Kerala from time immemorial has nurtured a very divine
and aesthetic line of protection of sacred groves, which was intermingled
with religious ways of social activities and worships. Such sacred groves are to
be protected from the angle of biodiversity also and the existing sacred
groves are the only islands of conservation amidst vast stretches of degraded
ecosystems apart from the forests.
6.5.3. Impact of clay and shell mining
Though the downstream area of Pamba River comes under the purview
of the present study, sand mining is a major problem in the downstream area
of the river especially in Kainakari panchayat. Although mining activities
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deplete DO of the water column, the effect will be predominant in
mechanical mining areas. In land areas, the lime shell mining operations
create certain negative impacts in land use, landscape and land stability.
Sand and clay mining in good paddy lands cause serious losses to agricultural
production, often irreversibly. Sand and clay mining as also shell mining is
prevalent in Kainakari panchayat, alone in the study area, and the activity
ought to be controlled, so as to avoid ill effects from the activity, but is
continued sustainably.
6.5.4. Pesticide pollution
Due to the intensive attempt to enhance food production increased
pressure was put on land in various means. The growing human and animal
populations are making increasing demand on natural resources resulting in
the exploration of resources in unsustainable manner (Swaminathan, 1991). It
is a known fact that excessive use of chemical pesticides and fertilizers
increasingly polluting agricultural products and infertile the agro-ecosystems.
Variable explosion in the wide use of harmful chemicals has led to many
problems like development of resistance to pesticides in target species, pest
resurgence, secondary pest outbreak and above all the environmental
pollution (Abduraheem and Rehman, 2007).
Being a most productive agricultural and aquacultural area, pesticide
pollution is the most serious in Kuttanad wetland system and needs to be
considered as a prime threat. From the farmers opinion major pesticides used
in Kuttanad agricultural field are Organo-phosphorus such as Asataf,
Dimecron, Ekalux, Hostathion, Malathion, Monocrotophos, Nuvacron, Rogor
and Metacid Synthetic, Pyrethroids such as Ambush, Tatareeva, Trebone and
Karate, organo-chlorins such as Lanite and Lindane. Excessive use of
pesticides in Kuttanad creates several human health effects as well as fish
diseases. In addition to that several useful organisms and the natural enemies
of crop pest have also vanished with the excessive use of pesticides. A study
undertaken by the Thiruvananthapuram Medical College has reported very
frequent cases of cancer of the lip, stomach, skin and brain, lymphoma,
leukemia and multiple myloma from the Kuttanad rice area of Kerala, linking
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the same to high pesticide use in the area (Indira Devi, 2007). Over reliance of
to synthetic pesticides without proper understanding of its consequences may
lead to an era of agricultural disaster in the long run than to an era of
agricultural prosperity.
6.5.5. Impact of tourism
The whole area of Kuttanad is being exploited for tourism and river
connecting to Kainakari to Edathuva at least could be considered to
enhance tourist traffic, targeting ancient monuments like Edathuva Church.
At the same time there is still scope for identifying tourism interest spots in all
the three panchayats. However, growing water tourism in the Kuttanad
wetland area especially Vembanad lake may cause a rapid urbanization
that increases demand for protected land or land adjacent to wetlands. This
can cause damages to wetland hydrology and water quality due to
drainage or fill activities on adjacent lands for construction of buildings and
parking lots. Additionally, the increasing demand for food may lead to more
intensive agricultural and fishing methods, with negative impacts on land use,
and the quality and the quantity of water.
6.5.6. Impact of Invasive alien species
Kuttanad wetlands are infested with an array of alien invasive species.
Of all invasive weed species, aquatic weeds are perhaps the most harmful.
Among these the floating plants such as Eichornnia crassipes (water
hyacinth), Pistia stratiotes, and Salvinia molesta are most common and most
aggressive weed elements. Currently, Eichornnia crassipes is the chief weed
element causing very serious threat to the Kuttanad water bodies (Kerala
Sastra Sahithya Parisht, 1978). Growth of these plants affects water quality,
depleting the dissolved oxygen, prevents entry of light into water column
affecting fish reproduction and survival and posing increased risks to human
health. Loss of oxygen from the water increases its acidity and, as a result,
aquatic biodiversity starts to decline. Aquatic weeds do not get wiped out
because of absence of saline intrusion. The thick weed mats make fishing
impossible and disrupt water transport and irrigation systems. More hazardous
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to humans is the risk of diseases (such as malaria and cholera), as the weeds
provide an ideal breeding ground for the vectors (e.g. mosquitoes and snails).
6.5.7. Thanneermukkam salt water barrage
The Thanneermukkam saline water barrier was designed in 1975 with a
good intension to prevent salinity intrusion into the southern part of the
Vembanad backwater system (Kuttanad) in the dry season and also to retain
the fresh water from the rivers flowing into the estuary. The structure has been
relatively successful in keeping the water in the Kuttanad fresh and enabling
cropping in the dry season to be increased. It has affected the natural fish
breeding activities in the area (Kurup et al., 1990). In fact, before the
construction of the Thanneermukkam barrage, the saline intrusion cleanses
out the water systems in many ways, preventing the growth of fresh water
aquatic weeds (Anilkumar, 2007). Moreover, the migration routes of marine
fish and prawns are interrupted by the barrier, its gates being closed during
the pre-monsoon period when maximum upstream migration takes place,
which has affected the fish production of Kainakari and Edathuva among the
study panchayats.
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