Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 May 2021 | 13(6): 18497–18507
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.5547.13.6.18497-18507
#5547 | Received 11 November 2019 | Final
received 17 April 2021 | Finally accepted 05 May 2021
Vaduvur and Sitheri lakes, Tamil Nadu, India: conservation and
management perspective
V. Gokula
1 & P. Ananth Raj 2
1,2 National College, Karumandapam, Tiruchirappalli, Tamil Nadu 620001, India.
1 gokulazoo@nct.ac.in
(corresponding author), 2 drpananthraj@gmail.com
Editor: Rajah Jayapal, Sálim Ali Centre for
Ornithology and Natural History (SACON), Coimbatore, India. Date of publication: 26
May 2021 (online & print)
Citation: Gokula,
V. & P.A. Raj (2021). Vaduvur and Sitheri lakes, Tamil
Nadu, India: conservation and management perspective. Journal of Threatened Taxa 13(6): 18497–18507. https://doi.org/10.11609/jott.5547.13.6.18497-18507
Copyright: © Gokula
& Raj 2021. Creative Commons Attribution
4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: None.
Competing interests: The authors
declare no competing interests.
Author details: V. Gokula is serving as Associate Professor & Head in the Department of
Zoology at National College, Tiruchirapalli, Tamil
Nadu. P. Ananath
Raj completed his PhD degree from the department of Zoology, National
College, Tiruchirapalli, Tamil Nadu. He is serving as
PG Teacher in Government Boys Higher Secondary School at Viralimalai,
Tamil Nadu.
Author contributions: VG designed and
supervised the study, PAR collected the data, VG and PAR analyzed the
data, and VG wrote the manuscript.
Acknowledgements: We thank the management of
National College, Tiruchirapalli and the Forest
Department of Tamil Nadu for providing necessary facilities and
permission.
Abstract: Wetlands are declining
globally. Hence, it is reasonable to
assume that most existing wetlands are impacted to some degree by human
land-use that in turn caused population declines in many wetland-dependent
taxa. The National Wetland Atlas has classified
Tamil Nadu as a wetland-rich state as they occupy 6.92% of geographic
area. However, studies on wetlands are
limited in Tamil Nadu. Hence, an attempt
was made to identify the threats to the Vaduvur and Sitheri lakes and their associated fauna. In total, 118 species of birds belonging to
87 genera, 48 families and 18 orders in Vaduvur Lake
and 87 species of birds belonging to 71 genera, 48 families and 16 orders in Sitheri Lake were recorded.
A total of 28 zooplankton species were recorded in both the lakes
comprising 14 species of rotifers, six species of cladocerans,
five species of copepods, two species of ostracods, and one species of
protozoa. A total of 15 species of fishes
were identified from the sellers who catch fishes from the Sitheri
Lake. The physico-chemical
parameters of water varied according to the seasonal fluctuations in rainfall
pattern. In general, wetland management
for waterbirds of these two lakes should focus on
providing suitable nesting habitats and available food resources for dependant
avifauna. Management of invertebrates,
amphibians, and fishes in these two lakes is one technique that can be used to
provide foraging opportunities for waterbirds. An integrated approach and increased co-operation would
result in the rational use of this freshwater resource leading to improved
standards of living around this lake.
Keywords: Illegal
trade, poaching, threats.
INTRODUCTION
Wetlands are declining
globally. Between 1993 and 2007, the
global acreage of wetlands decreased by 6% (Prigent
et al. 2012). Hence, it is reasonable to
assume that most existing wetlands are impacted to some degree by human
land-use that in turn caused population declines in many wetland-dependent
taxa. Wetlands have many successional
stages and hydroperiods, represented in close proximity, thus, managing
wetlands effectively requires an understanding of basic ecosystem processes
besides using appropriate management techniques that depend on target species,
coastal versus interior wetlands, available infrastructure, resources, and
management objectives.
The National Wetland Atlas,
prepared by the Ahmedabad (Gujarat) Space Application Centre (SAC), Indian
Space Research Organization (ISRO), has classified Tamil Nadu as a wetland-rich
state as they occupy 6.92% of the geographic area. One-hundred-and-twenty-five species of birds
including both migratory and resident that depend on wetlands fully or partly
and 28 other species found in the vicinity of wetlands are known from Tamil
Nadu. Although Tamil Nadu State has
several wetlands, studies are limited to very few: Point Calimere
(Sugathan 1982), Kaliveli
(Pieter 1987), Singanallur Lake (Reginald et al.
2007), Pallikaranai (Raj et al. 2010), Karaivetti (Gokula 2010), Vaduvoor (Gokula & Raj 2011),
and Sitheri (Gokula &
Raj 2015). The majority of research work
on wetland management in Tamil Nadu relates to the limnological and
ornithological aspects. Nevertheless,
the land-use changes and socio-economic activities leading to changes in
limnological and biodiversity aspects of these wetlands have not been explored
substantially. Moreover, the national
water sector agenda pays little attention to wetland management resulting in
over exploitation of wetland’s resources.
Hence, an attempt was made to identify the threats to the Vaduvur and Sitheri lakes and
their associated fauna.
STUDY AREA
The Vaduvur Lake, situated
between 10.698–10.706 0N & 79.309–79.322 0E, spread
over c. 128ha and Sitheri Lake, situated between
10.712–10.728 0N & 79.323–79.342 0E, spread over c.
87ha, are located at a distance of 20km from Mannargudi,
a town, situated between 10.636–10.677 0N & 79.432-79.450 0E
in Tiruvarur District in Tamil Nadu. The Vaduvoor Lake
was declared a bird sanctuary by the forest department in July 1999. The bunds help in holding the water up to an
average depth of c. 2.5m. Vegetation of
the lake consists of Prosopis chilensis, Azadirachta
indica, Tamarindus
indica, and Acacia nilotica
including planting of A. nilotica by
the forest department under the Sanctuary Management Program. The Sitheri Lake is
currently being maintained by the public works department, Tamil Nadu, however,
the forest department of Tamil Nadu has a plan to bring this wetland and its
components under the protected areas network.
The Vennaru River is the main source of water
in addition to the monsoon (largely from the north-east) for both the lakes.
METHODS
Birds were counted using direct count method from
selected vantage points following Bibby et al. (1992) and Sutherland
(1997). Counts were made four times in a month during which
birds were observed from 06.00 –10.00 hr and
16.00–18.00 hr, being their most active periods of
the day from September 2010 to February 2012.
No count was done during extreme weather conditions. The
water quality of the lakes was assessed using the standard methods described by
APHA (1996). Identification of
zooplankton was done by following Alfred et al. (1973) and Adoni
et al. (1985). Zooplankton samples were
collected from the two lakes by towing a plankton net, made up of bolten silk with a mesh size of 100µm, from surface water
to 1m depth. One-hundred litre of water
from the lakes was filtered through the zooplankton net and collected planktons
were preserved in 5% formalin. Planktons
were identified up to species level.
Planktons were enumerated using SedgwickRafter
chamber and species richness and diversity were calculated. Fish collected by the local people were
inspected and identified up to the species level, based on which, a list of
fish species for each lake was prepared.
Jayaram (1999) was followed to identify the fish fauna. Several visits were made around the lakes and
villages nearby for collecting information on threats to avifauna and two
lakes. Formal and informal interviews
were conducted with local people to prepare a list of threats to these two
lakes and dependant avifauna. During the fieldwork, anthropogenic activities, viz.,
hunting, illegal fishing, and woodcutting (if any) were monitored and
quantified (if possible) following Joshua & Johnsingh
(1994). Only fishing and illegal hunting
of birds were identified as threats to the wetlands. People
who are directly or indirectly involved in the above said two threats were
approached for additional quantitative (if possible) and qualitative
information. Fish markets were
periodically visited for collecting information on illegal bird trade. Informal interviews were conducted with those
traders for further details. Wherever
permission was granted, quantification were made on the number of individuals
and species of birds involved in the trade.
The methodology was based on the principles and procedures of the
Australian/New Zealand Standard for Risk Management ISO 31000:2009 (Standards
Australia 2009; AZ/NZS 4360:1999) and HB 203: 2000 Environmental Risk
Management – Principles and Process (Standards Australia 2009).
RESULTS AND DISCUSSION
In total, 118 species of birds belonging to 87 genera,
48 families, & 18 orders in Vaduvur Lake and 87
species of birds belonging to 71 genera, 48 families, & 16 orders in Sitheri Lake were recorded and the details are given
elsewhere (Gokula & Raj 2011, 2015). The numerical differences may be attributed
to the combination of any of the factors, viz., size and location of wetlands,
proximity to other wetlands, water level, foraging opportunity, food
availability, availability of nest-sites, inter and intra specific competition,
human pressure, site fidelity of bird species, and site history. Besides regular common migrants, both the
lakes harbour Near Threatened bird species, viz.: Darter Anhinga
melanogaster, Painted Stork Mycteria leucocephala, and Oriental White Ibis Threskiornis melanocephalus. Among the bird species recorded, the most
numerous were Garganey Anas querquedula and
Northern Shoveller Anas clypeata,
however, individuals of a majority of the species were poor in numbers. Little Grebe Tachybaptus
ruficollis, Little Cormorant Phalacrocorax
niger, Little Egret Egretta
garzetta, Cattle Egret Bubulcus
ibis, Indian Pond Heron Ardeola grayii, and Pheasant-tailed Jacana Hydrophasianus
chirurgus nest in Sitheri;
while, Little Grebe, Asian Openbill Aanastomus
oscitans, Cattle Egret, Black-crowned Night Heron
Nycticorax nyctiorx,
Grey Heron Ardea cinerea,
Little Egret, Little Cormorant Microcarbo niger, Pheasant-tailed Jacana nest in Vaduvur Lake. In
both the wetlands, birds breed largely during and after the north-east monsoon
as reported by Subramanya (2005) for majority of the heronries of Tamil
Nadu.
A total of 28 zooplankton species were recorded in
both the lakes comprising 14 species of rotifers, six species of cladocerans, five species of copepods, two species of
ostracods, and one species of protozoa (Table 1). A greater number of species of zooplanktons
was recorded during November to June followed by May to July (Table 2). The diversity of planktons was more during
the monsoon rather than in the summer in both the lakes, which is in contrast
to other such studies carried out in Tamil Nadu. Manikam et al. (2014,
2017) reported high diversity of planktons in summer and attributed it to
favourable temperature and availability of food in the form of bacteria,
phytoplankton, and suspended detritus during the season. Hence, a detailed
long-term study is needed to confirm it further.
The Sitheri Lake is a very
good fishery resource. A total of 15
species of fishes were identified from the sellers who catch fishes from the Sitheri Lake and the Vennaru River, a prime source for the two lakes (Table
3). Thiyagesan & Nagarajan (1995) reported the negative impacts
of the over exploitation of aquaculture and fisheries resources in inland and
coastal wetlands of the eastern coast of India on their bird life.
With respect to water quality the changes in water
chemistry has been considered to exert influence in the distribution of many
aquatic plant species (Catling et al. 1986; Shay
& Shay 1986; Chee & Vitt 1989; Engelhardt
& Ritchie 2001; Lentz-Cipollini & Dunson 2006). As waterbirds and
wetland dependant birds depend directly or indirectly on aquatic fauna and
flora which in turn depend on water chemistry, birds’ distribution is expected
to change with changes in water chemistry.
As anticipated the physico-chemical parameters
of water varied according to the seasonal fluctuations (Table 4). The limnological variables showed two
distinct clusters: July to December with high rainfall and January to April
with less/no rainfall (Figure 1). The
rainfall (both from north-west and south-east monsoons between June to December)
and lack of rainfall (between January to May) showed greater influences in the
values of water quality parameters in both the lakes.
Three major villages are situated around these two
lakes: Vaduvur Vadpathi (2,289 individuals belonging to 575 families of which
1,154 are males while 1,135 are females), Vaduvur Melpathi (3,010
individuals belonging to 817 families of which 1,478 are males while 1,532 are
females), and Vaduvur
Thenpathi (3,412
individuals belonging to 896 families of which 1,673 are males while 1,739 are
females). The
socio-economic status of the people of these villages revealed that both the
lakes play a vital role in the livelihood of many people. Agriculture is the main occupation of the
people of these villages and they greatly depend on the lake for irrigation and
other domestic purposes. Paddy is the main crop cultivated around these two
wetlands and it is grown three times in a year.
The first crop is known as ‘Kuruvai’ (the
short-term crop) with a duration of three and a half to four months from
June–July to October–November. The
second crop called the ‘Thaladi’ has a duration of
five to six months from October–November to February–March. The third is the ‘Samba’ (the long term) crop
and has a duration of almost six months from August to January. During the cultivation periods, in
particular, between the months of October and January, the agriculture fields
are water-logged with aquatic invertebrates.
Thus, the agriculture fields surrounding these two wetlands and in
nearby villages not only act as a unique foraging ground but also provide
various foraging opportunities to the waterbirds and
wetland dependant birds during their stay at in these two lakes. The
water-logging of agricultural fields often attracts waterbirds,
especially when they are close to other wetlands (Nagarajan & Thiyagesan 1996; Kahlert et al.
2007). Moreover, paddy fields support
the highest bird diversity when they are water logged with abundant aquatic
insects, worms, snails, and tadpoles (Deep 2008). Moreover, when they are flooded in winter
they often provide a good feeding habitat for large numbers of birds (Chan et
al. 2007). Croplands that are flooded to
a shallow depth act as temporary foraging grounds for waders. Some species appear to need very large
rice-fields while others prefer smaller ones and edge habitats (Burton et al.
2002). Hence, lakes with sufficient
water and surrounded by agriculture fields with agricultural activities are
more crucial to sustain the population of waterbirds
and wetland dependent birds that traditionally inhabit any wetland. Due to unusual drought and fall in rainfall
due to climate change, lack of interest in agricultural practices, and
conversion of agricultural land into human habitation, agricultural activities
in agriculture fields have drastically been declining not only around these
lakes but also in the entire district.
Recently, the Federation of
Tamil Nadu Agricultural Associations reported that from 2001 to 2011, nearly
8,67,582 farmers have stopped agriculture due to various reasons, including
huge losses. Interestingly, there was an
increase in the number of agricultural labourers during the period, as the
farmers sell their land for real estate and prefer to work on daily wages. They attributed the reason for the plight of
the farmers to wrong import policies of the government, unremunerative prices
for farmers’ produce, industrialization and urbanization, coupled with the
failure to divert the rain and other waters going to sea to the farmers’ fields,
by linking rivers.
As majority of the lakes in Tamil Nadu go dry in
summer, it is presumed that waterbirds move from
places lacking adequate water to places with adequate water ignoring site
fidelity. Although, both these lakes go
90% dry in the month of May, they still attract a significant number of waterbirds from other parts. The Spot-billed Pelican Pelecanus
philippensis being a late arrival (largely during
late November) particularly in the southern districts of Tamil Nadu performs
its breeding activity until the month of April (February to April being crucial
months to raise the young ones) while all other species complete their breeding
activities largely by January. As
majority of the lakes go dry from the month of February onwards in Tamil Nadu,
the movement of pelicans from their traditional sites to new lakes with
sufficient water is common (Gokula 2011). The Vaduvur Lake is
one such wetland that supports pelicans during the above said crucial
months. Hence, in order to support
Spot-billed Pelican, a near threatened bird, proper steps have to be taken to
sustain the water level during April and May.
Various kinds of threats such as excessive fishing,
poaching of birds, cattle grazing, fuel-wood collection, siltation, weed
invasion, and pollution were identified particularly for the lakes during the
study period. Earlier Wolstencroft et al. (1989) reported that these were the
major threats in Asia in various wetlands.
Thiyagesan & Nagarajan (1995) listed
similar threats to the coastal wetlands of Tamil Nadu, southern India. Divakaran (2000)
also noticed a majority of these threats in different islands of the Gulf of Mannar, southern India, causing great havoc for bird life
there. The forest department of Tamil
Nadu has protected the Vaduvur Lake under the bird
sanctuary category thus the lake is comparatively free from above said illegal
activities such as fishing and poaching of birds. All such activities have been prevailing in
the Sitheri Lake.
Waterbird harvest is widespread, long-standing, and an
important activity for local communities around the world. In many countries, the harvest takes place as
a primary food source, but sport or recreational hunting is also popular;
however, waterbird harvest has not been a popular
activity in India since time immemorial and it may either be due to the
availability of food resources in plenty or due to the culture. Sport or recreational hunting of waterbirds, however, was a part of the recreational
activities of kings/maharajas and it continued until the British colonial
period. Later, the Indian Wildlife
(Protection) Act 1972 prevented this activity to be practiced anywhere in
India. Still a nomadic community called
‘Narikurava’ in Tamil Nadu hunts birds for food as
well as commercial purposes. In the interview, some admitted they supply birds dead
or alive, specific or common to customers depending on their needs. Some suggested they should be given
controlled hunting permits enabling them to make a sustainable living while
protecting wildlife. Due to their small population size and the
insignificant demand for wild birds among the public comparing others (fish,
mutton, domestic chicken) in the market, however, it is generally assumed that
hunting is well below the sustainable utilization, a level commonly regarded as
a cornerstone in the conservation of nature.
In the present study, frequent visits were made to
fish markets of Vaduvur and Mannargudi
(a town situated 12km away from the study area) to assess the wild bird trade
from 2009 to 2015 (Table 5 & Image 1).
In total 68 visits were made of which wild bird trade was found on 26
occasions. On all the occasions, (except
three), no same person was found trading in wild birds. Two (belonging to Narikurava)
persons involved in wild bird trade were sighted on three occasions. When
approached for informal interviews we found many illegal wild bird traders made
good their escape, while a very few stayed and engaged in conversation. People
belonging to Narikurava though afraid to be photographed
with birds, revealed facts like where and how they caught the birds. In total, 974 birds belonging to 21 species,
11 families and eight orders were recorded in the wild bird trade. It even included the Spot-billed Pelican, a
Near Threatened bird. Among the orders, Coconiiformes dominated with seven species of birds
followed by Gruiformes with five species of
birds. Among the bird species,
White-breasted Waterhen (89), Little Egret (87), Common Coot (76), and Water
Cock (73) were sold in more numbers.
Although wild bird trade was found in all the months of the year, it was
more frequent during November to January.
All the species of birds were largely bought for the purpose of
meat. On one occasion, a crow was found
sold to a customer and the enquiry with the trader revealed that it was for the
purpose of black magic. He also revealed
that they do supply crow on request occasionally for the above said
purpose. The traders also revealed that
all the birds were caught from the paddy fields surrounding the wetlands during
early morning and late evening hours
using indigenious traps (such as clap trap, mesh
nets, and nooses).
Although the forest officials frequently intercept, and arrest those
involved in the hunting of wild birds in and around Vaduvur
area, patrolling larger areas surrounding these two wetlands is not possible
and feasible with the existing work force in the forest department. Often, arrested people are booked under the
provisions of the Indian Wildlife (Protection) Act 1972. In the early
1970s and 1980s, over 150 families of different communities from Nagapattinam, Thanjavur, and Thiruvarur districts were involved in trapping migratory
shorebirds and ducks that used to frequent the coastal wetlands, in several
lakhs, during the migratory season (October to April). Now, many bird trappers have shifted to
fishing as they were looked down upon for carrying on this illegal
profession. Cattle egrets and pond
herons are often bought by roadside restaurants and wine shops to serve and
sell as chicken. Regardless of months,
Cattle Egrets and Pond Herons are trapped every day for this purpose. Hence, proper awareness programmes to other
communities and alternate sources of livelihood for Narikurava
are essential to wean them away from their traditional but destructive
profession. All these birds involved in
the illegal trade play a very significant role in the agro-ecosystem
as they feed on various insect species and thereby control the pest population.
Anand (1999) reported desiltation
was not only useful in terms of improvement of irrigation and fisheries
potential, but also to the increase of wildlife diversity and use. During the rainy season the eroded soil from
their catchments, gets dumped into these lakes, which in turn reduces the water
holding capacity of the lake. Siltation,
a serious problem, results in low water depth
thereby facilitating the invasion of weed patches. Vallenweider (1968)
reported that water bodies with less water depths would be more affected by
eutrophication problems. The Ipomoea
aquatic (weed) invasion was very extensive in these lakes. Anand (1999) observed that the Ipomoea
invasion changed the water quality and reduced the primary production and
nutrient cycle. As a result the weeds
should be cleared either manually or by application of weedicide. Such a step will increase the irrigation
potential of the lake and improve the condition for the wildlife, especially waterbirds.
The lake area is used by surrounding villagers for
grazing their domestic livestock especially during summer. This intensive cattle grazing could result in
breaking the nutrient cycle of the lake.
Further, the trampling cattle might harden the soil surface and reduce
the aeration of the lake. Earlier Meganathan (2002) also expressed similar apprehensions for
the freshwater lakes of Tamil Nadu. The
local people must be educated in this aspect.
The surrounding village people are using the lake for washing their
livestock. The livestock are allowed to
freely drink and bathe in this lake.
This cattle washing pollutes the water and acts as a deterrent for waterbirds. Hence,
cattle washing should be prohibited in the lake.
Another threat is wood collection for fuel by the
local villagers from the lakes and its immediate surroundings. Acacia, Zizypus,
and Prosophis were the plants cut
for fuel wood. They are the roosting and
nesting places for birds like openbill storks and night herons. Dickson et al. (1995) stated that
protection of vegetation along the sides of the wetlands is important to retain
water quality and accommodate wildlife including breeding birds. Hence, this vegetation, especially at the
northern region of the Vaduvoor Lake and the entire Sitheri Lake must be given full attention and protection to
prevent human disturbances to nesting activities through wood removal. In 2015, Prosopis chilensis—then roosting and nesting sites for several species
of birds, were completely removed by the people, which in turn affected the
avifauna
Although many of the heronries in Tamil Nadu, despite
the stench emanating from the nesting activities of the birds, are zealously
protected by villagers (e.g., Kanjirankulam, Udayamarthandapuram, Vettangudi, Vedanthangal, and Koonthakulam),
villagers in and around the Vaduvoor Lake lack such
interest towards protection of birds.
Usage of crackers and musical instruments by villagers are very common
during festival times in Vaduvoor Lake area.
A prominent Kothandaramar Temple and a
community temple are situated around the Vaduvoor
Lake. Although, festivals of Kothandaramar Temple largely come between June and August,
disturbance to birds by the devotees are considerably less as birds are less
during these months. Frequent family
functions held at the community temple situated at the edge of the lake,
however, cause a major threat to the breeding birds particularly during the
migration and breeding seasons. It has
been suggested that the greatest and most depressing problem in conservation is
not habitat loss or overexploitation but the human indifference to such
problems (Balmford 1999). Overcoming such indifference is likely to
depend on providing both the opportunities to appreciate areas and species, and
education to highlight the ecological, aesthetic, cultural, spiritual, recreational,
and economic importance. Education is
one of the major techniques available to conservationists through which change
in behaviour or compliance with new legislation can be achieved. Moreover, maintaining protected areas is
easier if there is public support, which often leads to political and financial
support and greater adherence to rules and regulations (Shepard & McNeely
1998). Hence, a proper public awareness
program has to be initiated about the conservation of birds and lakes among the
public.
As the lake is situated on one side of the Trichy-Mannargudi main road, vehicular sound is a great threat to
the breeding birds. High decibel noise
often disturbs the breeding activities of the birds, and frail chicks. Hence, usage of horns by vehicles should be
banned from start to end of the lake at least during the peak breeding season
of birds.
Pesticides, manures, and fertilizers are being
increasingly used to ensure greater production of food in the nearby paddy
fields around the lake. Some of these
chemicals find their way into soils, water and other parts of the environment
as a result of direct application or by indirect means. Hence, it is also necessary to monitor the
water for possible pesticide contaminants since the lake is also the main
source of water supply for agricultural consumption. In addition to awareness, volunteers should
be trained to monitor the breeding population of birds and other threats to
birds and wetlands.
CONCLUSION
In general, wetland management for waterbirds
of these two lakes should focus on providing suitable nesting habitats and
available food resources for dependant avifauna. Management of invertebrates, amphibians, and
fishes in these two lakes is one technique that can be used to provide foraging
opportunities for waterbirds. Most species often rely much on nearby
aquaculture fields thus a straightforward ‘farm crisis’ may badly affect the
avifauna of these two lakes. Hence,
agricultural activities around the two lakes should be encouraged. The water
level and water quality of the lake should be properly maintained to cater to
the needs of both irrigation and wildlife.
Periodic desilting should be initiated with proper care and planning to
provide a variety of depth levels.
Cattle grazing and cattle washing in the lake should be totally
prohibited. The weed Ipomoea
should be removed totally. Poaching of waterbirds should be stopped by effective steps, such as
better vigil and weaning of nomadic life from wildlife hunting by educating
them and providing alternative livelihood.
An awareness campaign must be conducted so that the local public
realizes the significance of the lake in terms of their wildlife values and
need to utilize them judiciously and sustainably for mutual benefit. There is an excellent potential for
developing these lakes as very good tourist attractions since these lakes are
situated near other famous tourist areas such as Point Calimere
Wildlife Sanctuary, Karaivetti Lake, and other
cultural heritage sites (such as Tharangambadi, Thanjavur, and Velankanni). Ecotourism would increase the income of the
local people. Hence, an integrated
approach and increased co-operation would result in the rational use of this
freshwater resource leading to improved standards of living around this lake.
Table 1. Species of planktons recorded in Vaduvur and Sitheri lakes during
the study period.
|
|
Vaduvur Lake |
Sitheri Lake |
|
Group |
Species |
Species |
|
Protozoa |
Vorticella sp. |
Vorticella sp. |
|
Rotifera |
Brachionus calyciflorus |
Brachionus calyciflorus |
|
Rotifera |
B. quadridentatus |
B. quadridentatus |
|
Rotifera |
B. forticula |
B. forticula |
|
Rotifera |
Euchlanis sp. |
|
|
Rotifera |
Horella brehmi |
Horella brehmi |
|
Rotifera |
Lepadella sp. |
|
|
Rotifera |
Mytilina sp. |
Mytilina sp. |
|
Rotifera |
Notholca sp. |
Notholca sp. |
|
Rotifera |
Trichotria sp. |
Trichotria sp. |
|
Rotifera |
Trichocera rattus |
Trichocera rattus |
|
Rotifera |
Testudinella patina |
Testudinella patina |
|
Rotifera |
Asplanchna brightwelli |
|
|
Rotifera |
Lecane lunaris |
Lecane lunaris |
|
Rotifera |
L. bulla |
L. bulla |
|
Cladocera |
Alonella sp. |
Alonella sp. |
|
Cladocera |
Bosmina longirostris |
Bosmina longirostris |
|
Cladocera |
Daphnia carinata |
Daphnia carinata |
|
Cladocera |
Diaphanosoma sp. |
|
|
Cladocera |
Diaphanosoma sp. |
Diaphanosoma sp. |
|
Cladocera |
Moina daphnia |
Moina daphnia |
|
Copepoda |
Calonoid copepod |
Calonoid copepod |
|
Copepoda |
Heleodiaptomus viduus |
Heleodiaptomus viduus |
|
Copepoda |
Mesocyclops hyalinus |
Mesocyclops hyalinus |
|
Copepoda |
Thermocyclops sp. |
Thermocyclops sp. |
|
Copepoda |
T. crassus |
T. crassus |
|
Ostracoda |
Cypris sp. |
Cypris sp. |
|
Ostracoda |
Stenocypris malcolmsoni |
Stenocypris malcolmsoni |
Table 2. Species richness and diversity of planktons recorded
during various months of the study area.
|
|
Vaduvur |
Sitheri |
Vaduvur |
Sitheri |
|
months |
Taxa_S |
Taxa_S |
Shannon_H |
Shannon_H |
|
Sep-10 |
19 |
16 |
2.795 |
2.642 |
|
Oct-10 |
23 |
19 |
2.963 |
2.784 |
|
Nov-10 |
28 |
24 |
3.132 |
3.009 |
|
Dec-10 |
28 |
24 |
3.127 |
3.007 |
|
Jan-11 |
21 |
17 |
2.841 |
2.636 |
|
Feb-11 |
17 |
16 |
2.614 |
2.566 |
|
Mar-11 |
13 |
12 |
2.336 |
2.272 |
|
Apr-11 |
8 |
8 |
1.895 |
1.895 |
|
May-11 |
9 |
9 |
2.062 |
2.062 |
|
Jun-11 |
8 |
8 |
1.934 |
1.934 |
|
Jul-11 |
8 |
8 |
1.992 |
1.992 |
|
Aug-11 |
11 |
11 |
2.322 |
2.322 |
|
Sep-11 |
18 |
16 |
2.768 |
2.655 |
|
Oct-11 |
23 |
19 |
2.9 |
2.729 |
|
Nov-11 |
28 |
24 |
3.09 |
2.961 |
|
Dec-11 |
27 |
24 |
3.018 |
2.934 |
|
Jan-12 |
20 |
17 |
2.73 |
2.596 |
|
Feb-12 |
17 |
15 |
2.566 |
2.487 |
Table 3. List fish species recorded in the Sitheri Lake, Tamil Nadu, India.
|
|
Fish |
Vernacular name |
National status, Global status (in parenthesis) |
|
|
Cyprinidae |
|
|
|
1 |
Barilius bendelisis |
Vannathikendai |
LRnt/N (LC) |
|
2 |
Puntius sophore |
Kullakendai, Mochakendai |
LRnt/N (LC) |
|
3 |
labeo calbasu |
Karupan sel, Selukendai |
LRnt/N (LC) |
|
4 |
Cirrhinus reba |
reba |
VU (LC) |
|
5 |
Puntius conchonius |
Vallikendia |
VU (LC) |
|
6 |
Rasbora daniconius |
Bhavanikendia |
NE (LC) |
|
|
Cobitidae |
|
|
|
7 |
Lepidocephalus thermalis |
Ayirai |
NE (LC) |
|
|
Bagridae |
|
|
|
8 |
Mystus cavasius |
Naikeluthi |
LRnt/N (LC) |
|
9 |
Mystus vittatus |
Vazhppu |
VU (LC) |
|
10 |
Mystus bleekeri |
Keluthi |
VU (LC) |
|
|
Cichlidae |
|
|
|
11 |
Etroplus suratensis |
Sella kasu, Puradi, Salladai meen |
NE (LC) |
|
12 |
Etroplus maculatus |
Sethakendai, Bommi |
NE (LC) |
|
|
Gobiidae |
|
|
|
13 |
Awaous gutum |
Ulluvai,Kalulluvai |
VU (LC) |
|
|
Clariidae |
|
|
|
14 |
Clarias batrachus |
Thalmeen, Thal Kendia |
VU (LC) |
|
|
Mastacembelidae |
|
|
|
15 |
Mastcembelus armatus |
Aarrah |
VU (LC) |
|
|
|
|
|
EN —Endangered | VU—Vulnerable | LRnt—Lower
Risk near threatened | NE—Not Evaluated | LC –Least concern (IUCN status).
Status nationally as per CAMP assessment (Molur & Walker 1998).
Table 4. Descriptive statistics of water quality
parameters recorded during various months of the study area.
|
|
Descriptive Statistics: Vaduvur
Lake |
|
|
|
Descriptive Statistics: Sitheri
Lake |
|
||||||
|
Water Quality Parameters |
Min |
Max |
Mean |
SE |
V |
SD |
Min |
Max |
Mean |
SE |
V |
SD |
|
Turbidity
(NTU) |
8.00 |
32.00 |
18.56 |
1.72 |
53.08 |
7.29 |
8.00 |
30.00 |
17.39 |
1.61 |
46.60 |
6.83 |
|
Total
Dissolved Solids |
270.00 |
595.00 |
394.89 |
20.80 |
7785.75 |
88.24 |
265.00 |
560.00 |
385.67 |
20.37 |
7472.12 |
86.44 |
|
Electrical Conductivity MicS/cm |
415.00 |
912.00 |
605.56 |
31.88 |
18292.73 |
135.25 |
415.00 |
897.00 |
595.67 |
29.25 |
15404.40 |
124.11 |
|
pH |
6.74 |
8.00 |
7.38 |
0.06 |
0.08 |
0.28 |
6.40 |
7.90 |
7.33 |
0.08 |
0.10 |
0.32 |
|
Alcalinity pH as CaCO3 (mg/l) |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
|
Alkalinity Total as CaCO3(mg/l) |
105.00 |
222.00 |
146.17 |
6.87 |
848.97 |
29.14 |
108.00 |
223.00 |
143.89 |
6.89 |
855.28 |
29.25 |
|
Total
Hardness as CaCO3(mg/l) |
81.00 |
238.00 |
126.06 |
8.94 |
1437.59 |
37.92 |
78.00 |
237.00 |
123.22 |
8.71 |
1366.89 |
36.97 |
|
Calcium
as Ca(mg/l) |
24.00 |
61.00 |
33.33 |
2.11 |
79.88 |
8.94 |
24.00 |
56.00 |
31.44 |
1.81 |
58.97 |
7.68 |
|
Magnesium
as Mg (mg/l) |
4.00 |
20.00 |
10.56 |
0.93 |
15.44 |
3.93 |
5.00 |
19.00 |
10.00 |
0.82 |
12.00 |
3.46 |
|
Iron
Total as Fe (mg/l) |
0.00 |
2.50 |
0.72 |
0.16 |
0.44 |
0.66 |
0.00 |
2.20 |
0.67 |
0.14 |
0.36 |
0.60 |
|
Manganese
as Mn (mg/l) |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
|
Free
Ammonia as NH3 (mg/l) |
0.00 |
1.13 |
0.48 |
0.08 |
0.11 |
0.33 |
0.00 |
1.10 |
0.43 |
0.07 |
0.08 |
0.28 |
|
Nitrite
as NO2 (mg/l) |
0.00 |
0.45 |
0.14 |
0.04 |
0.03 |
0.16 |
0.00 |
0.45 |
0.13 |
0.04 |
0.02 |
0.15 |
|
Nitrate
as NO3 (mg/l) |
0.00 |
5.00 |
0.67 |
0.38 |
2.59 |
1.61 |
0.00 |
4.00 |
0.56 |
0.30 |
1.67 |
1.29 |
|
Chloride
as Cl (mg/l) |
48.00 |
127.00 |
91.06 |
5.71 |
585.94 |
24.21 |
43.00 |
120.00 |
88.83 |
5.17 |
480.50 |
21.92 |
|
Fluoride
as F (mg/l) |
0.00 |
0.40 |
0.19 |
0.02 |
0.01 |
0.08 |
0.00 |
0.40 |
0.14 |
0.02 |
0.01 |
0.08 |
|
Sulphate
as SO4 (mg/l) |
2.00 |
36.00 |
23.44 |
2.67 |
128.26 |
11.33 |
6.00 |
34.00 |
23.00 |
2.30 |
94.94 |
9.74 |
|
Phosphate
as PO4 (mg/l) |
0.08 |
1.64 |
0.60 |
0.11 |
0.20 |
0.45 |
0.07 |
1.54 |
0.59 |
0.10 |
0.19 |
0.43 |
|
Tidy's as O |
0.40 |
1.84 |
0.94 |
0.11 |
0.20 |
0.45 |
0.40 |
1.70 |
0.93 |
0.10 |
0.19 |
0.43 |
Table 5. Various species of birds recorded in the
illegal trade.
|
|
|
|
|
|
Used in trade as/for |
|
|
|
|
||
|
|
Common name |
Aviculture/pet use |
Meat |
Sport |
Medicinal use |
Black magic |
Available months |
Availability rating |
Frequency of occurrence |
Number of visits |
Total number birds found |
|
1 |
Little Grebe Tachybaptus
ruficollis |
* |
* |
|
|
|
Nov–Feb |
Frequent |
18 |
26 |
67 |
|
2 |
Spot-billed Pelican Pelecanus
philippensis |
|
* |
|
|
|
Nov–Jan |
Rare |
1 |
26 |
1 |
|
3 |
Little Cormorant Phalacrocorax
niger |
* |
* |
|
|
|
Nov–Jan |
Less Frequent |
4 |
26 |
12 |
|
4 |
Little Egret Egretta garzetta |
|
* |
|
|
|
Nov–Jan |
Frequent |
22 |
26 |
87 |
|
5 |
Grey Heron Ardea cinerea |
|
* |
|
|
|
Nov–Jan |
Less frequent |
4 |
26 |
5 |
|
6 |
Large Egret Casmerodius
albus |
|
* |
|
|
|
Nov–Jan |
Less frequent |
5 |
26 |
8 |
|
7 |
Cattle Egret Bubulcus
ibis |
|
* |
|
|
|
All the months |
Very frequent |
26 |
26 |
67 |
|
8 |
Indian Pond-Heron Ardeola
grayii |
|
* |
|
|
|
All the months |
Very frequent |
26 |
26 |
56 |
|
9 |
Black-crowned Night Heron Nycticorax
nycticorax |
|
* |
|
|
|
All the months |
Very frequent |
26 |
26 |
69 |
|
10 |
Asian Openbill-Stork Anastomus
oscitans |
|
* |
|
|
|
Nov–Jan |
Rare |
2 |
26 |
2 |
|
11 |
White-breasted Waterhen Amaurornis
phoenicurus |
|
* |
|
|
|
Nov–Jan |
Frequent |
16 |
26 |
89 |
|
12 |
Water Cock Gallicrex cinerea |
|
* |
|
|
|
Nov–Jan |
Frequent |
14 |
26 |
73 |
|
13 |
Purple Moorhen Porphyrio
porphyrio |
|
* |
|
|
|
Nov–Jan |
Frequent |
15 |
26 |
67 |
|
14 |
Common Moorhen Gallinula
chloropus |
|
* |
|
|
|
Nov–Jan |
Frequent |
16 |
26 |
68 |
|
15 |
Common Coot Fulica atra |
|
* |
|
|
|
Nov–Jan |
Frequent |
18 |
26 |
76 |
|
16 |
Pheasant-tailed Jacana Hydrophasianus
chirurgus |
|
* |
|
|
|
Nov–Jan |
Frequent |
14 |
26 |
56 |
|
17 |
Gull-billed Tern Gelochelidon
nilotica |
|
* |
|
|
|
Nov–Jan |
Frequent |
14 |
26 |
45 |
|
18 |
Common Tern Sterna hirundo |
|
* |
|
|
|
Nov–Jan |
Frequent |
14 |
26 |
46 |
|
19 |
Little Brown Dove Streptopelia
senegalensis |
* |
* |
* |
* |
|
All the months |
Frequent |
19 |
26 |
45 |
|
20 |
Asian Koel Eudynamys scolopacea |
|
* |
|
|
|
All the months |
Frequent |
15 |
26 |
34 |
|
21 |
House Crow Corvus splendens |
|
|
|
|
* |
|
Based on order |
1 |
26 |
1 |
|
|
Total |
|
|
|
|
|
|
|
|
|
974 |
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