1. The Pallikaranai Marsh

The Pallikaranai Marsh, (located on the geo-coordinates of 12.949371 N latitude and 80.218184E longitude), is one of the last remaining natural wetlands of Chennai city. It is locally known by the generic Tamil name ‘kazhuveli’ which means a flood plain or water logged area.

On its eastern periphery, the Marsh is flanked by the Buckingham Canal and the Old Mahabalipuram Road, which houses the Information Technology (IT) Corridor. The southern and western boundaries are typified by mixed residential and institutional land use. To the North of the Marsh, there are dense human habitations and public infrastructure such as the Mass Rapid Transit System.

Pallikaranai Marsh drains an area of 250 km2 of South Chennai encompassing 65 wetlands through two outlets viz., Okkiyam Madavu and the Kovalam creek and falls into the Bay of Bengal. The topography of the Marsh is such that it always retains some storage, thus forming a classic wetland ecosystem.

The water Canvas

Pallikaranai Marsh is a part of the vast Bay of Bengal Large Marine Ecosystem. It is one of the few natural coastal aquatic habitats that qualify as a wetland in India. The seasonal dynamics in water volume, spread and chemistry, both historical and current, have rendered the Pallikaranai Marsh a biodiversity-rich South Indian wetland.
This uniquely heterogeneous hydrology and ecology also makes the Marsh one of the most diverse natural habitats of the country. Biodiversity of Pallikaranai Marsh is typified by the presence of species representing various faunal groups, of which birds, fishes and reptiles are the most prominent. It is the natural habitat to some of the most endangered reptiles such as the Russel’s Viper and birds such as the Glossy lbis, Pheasant-tailed Jacana etc., The Marsh also has the distinction of new records of reptiles and plants being described, on a rather regular basis since 2002.

Lost Forever

Large parcels of the Pallikaranai Marsh have been lost due to reduction of wetland area, fragmentation and adhoc manipulation, destroying 90% of the Marsh. The remnant 10%, which is a Protected Area is the last hope for the city of Chennai.

Ecological Roots:

A large part of Southern Chennai was historically a flood plain as evidenced by the soil type of the region, which is described as recent alluvium and granite gneiss. Spread over 50 sq.km, it comprised of a large Marsh (Pallikaranai Marsh), smaller satellite wetlands, large tracts of pasture land and patches of dry forests (Guindy National Park, Nanmangalam Forest and the Theosophical society). The composite Nature of the landscape can be defined as a coastal plain with intermittent and overlapping habitat types of cultivation, wetlands and scrub forests. Based on the study of sediments, it has been established that the Marsh is not less than 1000 years old. Sub-fossils of marine crustaceans and molluscans unearthed locally reinforce the suggestion that there was historical influence of the sea on the Marsh.
It is also of significance that the smaller wetlands that surrounded the Marsh served as the only source of irrigation for the area, which thrived on paddy and green leafy vegetable cultivation. This gave the Marsh a legendary status since the village did not have wells or dug-out ponds, which are the norm in the Northern districts of Tamil Nadu (TN). The presence of a freshwater aquifer running parallel to the coast has contributed rather significantly to the expansion of the city’s boundaries in the south which is one of the may pointers to the presence and importance of the south Chennai Flood plain.

An area of 694Ha is under the control of Forest Department and is being declared as a Reserve Forest under Section 16 of Tamil Nadu Forest Act - 1882

The Protection and Conservation of Pallikaranai Marsh is a standing testimony of science-based advocacy, cohesive civil society engagement and a proactive Government. The Conservation Authority of Pallikaranai Marshland exemplifies this through the implementation of an Adaptive Management Programme for the Marsh.

How Unique

The Pallikaranai Marsh is part of the Chennai River Basin. More specifically, it is part of the Adyar River, whose history is not only rather scantily known, but is also rather varied in terms of the original course and hydrology. Ground evidence in and around the Marsh establish historical connectivity to a river, as indicated by the presence of a high number of water wash rocks. However, in the absence of robust geological studies, conclusive statements on the connectivity of the Marsh to Adyar river have not been provided. However, the strong substantiation provided by the watershed maps developed for the region validates the hypothesis.
Lack of understanding about the importance of the Marsh in an Urban environment as a flood regulator and as a highly productive habitat has resulted in the Marsh being reduced to around one-tenth of its original extent.

Large Marine Ecosystem

Although tropical in bio-climate, the influence of the Bay of Bengal has been significant on the Marsh. Dramatic changes in its hydrology and biodiversity witnessed annually may be attributed to the maritime influence and the vagaries of the North East Monsoon. The fact that the Marsh is so close to the sea and yet not fully estuarine is a unique character indeed. Parts of the Marsh are well below the mean sea level and qualify as low-lying basins. It is but natural that some parts of the Marsh are estuarine / brackish and harbour maritime animals such as mud crab, window-pane oysters and other bivalves.
The mixing of freshwater and seawater is brought about by the huge volume of surface runoff that the Marsh receives year after year during the monsoons. A right mix of freshwater and seawater is important in maintaining the ecological integrity of the Marsh. For , in the natural process of ecological succession, Marshes tend to give way to grasslands and scrub, eventually attracting the colonization of woody shrubs and trees. The heavy inflow of freshwater every year and the influence of tidal water that is brackish (if not saline) have limited the vegetation to herbaceous plants including salt tolerant
Sedges like fimbristylis triflora and grasses, Surface runoff from almost all sides, the tidal influence from the south and southwest and the dense growth of emergent aquatic plants have balanced siltation, creating extensive mudflats and wide sediment banks that border the shallow water.

The Living System.

Life in and around the Pallikaranai Marsh is contributed equally by it delicately balanced hydrology and resultant biodiversity. The natural geo-chemical cycles of the Marsh, although considerably disturbed by highly transformative human interference such as waste disposal and heavy footprint habitation and the associated infrastructure development, continue to sustain its unique hydrology and biodiversity.
Heterogeneous landscapes are known to support greater biodiversity than landscapes that are monotonous. The watershed-landscapes that are monotonous. The watershed- landscape that cradles the Pallikaranai Marsh is a mosaic of freshwater, brackish water, estuarine conditions, beaches, sea, wooded plains and hillocks. There has been a steady increase in the diversity of birds and their populations in the past 10 years. While the obvious sign of resilience has been the overall increase in birds which is an indication that the underwater biodiversity is also resilient and the ecological web that sustains the Pallikaranai Marsh is relatively intact.
Pallikaranai Marsh land in a treasure trove of biodiversity and is home to a wide array of species. There are 625 species of Plants and animals. There are 176 recorded species of birds. The bird diversity is an indicator of the health of the Marsh.



2. Bird Sanctuaries in Tamil Nadu

All the sanctuaries in Tamil Nadu including Point Calimere, Vedanthangal and Pulicat are significant for nesting of resident birds. Koonthankulam and Karaivetti sanctuaries support thousands of migratory ducks and geese as well. Sanctuaries like Vedanthangal are situated amidst agrarian landscapes and birds spend the day out there in the fields feeding and return back to the lake in the evening for shelter. Out of 223 species of birds recorded from the coastal wetlands of India, the highest number of species was recorded from the east coast. The order Charadriiformes was highest in dominance followed by Falconiformes and Ciconiiformes. 31 threatened birds species were recorded from the coastal wetlands. Hence, there is a need to protect coastal and marine areas with high priority conservation for future research on bird communities.

The brief details of Bird Sanctuaries in Tamil Nadu (as on 01-01-2016) are stated below:

 

Sl. No

Name of Sanctuary

Area in ha

Legal status

G.O.Ms.

No.in which declared

District in which located

Major Species found

Section of Wildlife (Protection) Act under which

declared

1

Vedanthangal Birds Sanctuary

30.000

PWD TANK

199 E&F

Department dated 3.7.98

Kanchee puram

Cormorants, egrets, grey heron, Open billed stork, Pelicans, migratory birds like garguney, teals, shovallers

Final notification issued u/s 26A(1)

2

Karikili Birds Sanctuary

61.210

PWD TANK

332 E&F

Department dated 23.5.89

Kanchee puram

Cormorants, egrets, grey heron, spoon billed stork,

18(1)

3

Vettangudi birds Sanctuary

38.400

PWD TANK

574 E&F

Department dated

3.6.77

Sivagangai

Cormorants, egrets, herons, teals, pelicans

18(1)

4

Kanjirankulam Birds Sanctuary

104.000

PWD TANK

684 E&F

Department Dated

21.9.89

Ramanatha puram

Cormorants, egrets, herons, teals, pelicans

18(1)

5

Chitrangudi Birds Sanctuary

47.630

PWD TANK

684 E&F

Department dated 21.9.89

Ramanatha puram

Cormorants, egrets, herons, teals, pelicans

18(1)

6

Udayamarthanda puram Birds Sanctuary

45.280

PWD TANK

379 E&F

Department dated 31.12.98

Tiruvarur

Little cormorant, darter, spoon bill, Indian Reef Heron, Grey heron, white

necked stork

Final notification issued u/s 26A(1)

7

Vaduvoor birds Sanctuary

128.100

PWD TANK

169 E&F

Department dated 22.7.99

Tiruvarur

Cormorants, egrets, ibis, herons and many variety of birds

Final notification issued under section

26A(1)

8

Koonthankulam- Kadankulam Birds Sanctuary

129.000

PWD TANK

301 E&F

Department dated 30.11.94

Tirunelveli

Grey pelican, painted stork, white Ibis, jackal,

rat snake

18(1)

9

Karaivetti Birds Sanctuary

453.710

PWD TANK

92 E&F

Department

Dated 5.4.99

Arialur

Egrets, pelican, Grey heron, White Ibis, Spoon bill

18(1)

10

Vellode Birds Sanctuary

77.180

PWD TANK

44 E&F

Department dated 29.2.2000

Erode

Spoon bill, Teals, Pintail ducks, Darter

Final notification issued u/s

26A(1)

11

Melaselvanur- Kilaselvanur Birds Sanctuary

593.080

PWD TANK

57 E&F

Department dated 10.3.98

Ramanatha puram

Grey Pelican, Painted Stork

18(1)

12

Theerthangal Bird Sanctury

29.290

PWD TANK

G.O.Ms No.220 E&F

Department dated

15.12.2010

Ramanatha puram

White -breasted Kingfisher, Spot- billed Pelican, Brahminy Kite

18(1)

13

Sakkarakottai Tank Birds Sanctuary

230.490

PWD TANK

G.O.Ms. No 114 E&F

Department dated

17-04-2012

Ramanatha puram

Spot billed Pelican, Egret, Common Myna, Grey Heron , Little Cormorant,

Black Kite etc

18( 1 )

14

Oussudu Lake Birds Sanctaury

331.785

PWD TANK

G.O.Ms. No 49 E&F

Department dated

31-03-2015

Villupuram

Spot billed Pelican, Egret, Common Myna, Grey Heron , Little Cormorant,

Black Kite etc

18( 1 )

15

Pulicat Lake Birds Sanctuary

15367.000

LAKE

1247E&F

Department dated 22.9.80

Tiruvallur

Spot billed Pelican, Egret, Common Myna, Grey Heron , Little Cormorant,

Black Kite etc

18( 1 )

 

Total

17666.155

 

 

 

 

 


Threats & Issues:

 

Insufficient Water availability

 

Almost all the sanctuaries are chiefly dependant on the monsoon for water storage. Delay in the onset of monsoons, scanty rainfall lead to late or poor water storage in the tanks. Apart from runoff from rainfall, most of these tanks are dependent on an external source like water channel bringing in water from a dam or tank or river for input of water. Consistent and prolonged drought situations exist in some areas, for instance Kanjirankulam, Mel-Keelselvanur. More often, delayed rainfall results in delayed bird arrival.

 

Pollution of water bodies

 

Unscrupulous use of pesticides and fertilisers in present day agriculture is a major source of contamination of our water bodies. The runoff waters from these fields carry with them loads of pesticide and nutrient load into the tanks leading to nutrient accumulation. Organic wastes like bird excreta, dried plant material also add upto the load. Over a period of time, the nutrient load has given to algal blooms and invasion of exotic weeds. Eichhorniacrassipes, Salviniaauriculata, Pistia stratiotes, Lemnaminor, Wolffiasp, Azollapinnata, etc often form thick mats in different areas of the tanks and affect the native vegetation. The algal blooms and invasive species replace the native macrophytes which are the major attractants to duck varieties. Due to the high Biological Oxygen Demand (BOD), the water will turn foul soon and eliminate all the aquatic organisms including fish.

 

In areas like Pulicat lake and Point Calimere, the effluents of aquaculture farms alters the water quality of water bodies causing degradation of biodiversity. Prawn-and crab-farms set up by private entrepreneurs along the margins drain water from the lake all round the year. More than this, the untreated effluent waters from the culture ponds discharged back into the lake degrades the quality of water and substratum in the lake, bringing about changes in the benthos (bottom biodiversity), nekton (swimming organisms), including fish, diversity.


Changes in water dynamics of rivers

 

In brackish water ecosystems like Pulicat lake, freshwater brought in by rivers and streams are crucial in maintaining the hydrology of the lake.

 

Impact of Lake-Mouth Closure on Hydrology

 

The lake-mouth tends to become narrower and shallower during the post-monsoon months primarily due to the accretion of sand, resulting in the formation of a sand-bar across the lake-mouth. As a result, the impact of the ebb (low) and flow (high) tides in the lake tends to be feeble and hence depth of the water in the lake tends to decline. This has major consequences on the biodiversity and fisheries in this lake. The impounded lake water subjected to evaporation reaches hyper saline levels.

 

Siltation

 

Loads of silt and substratum carried into the lakes and tanks reduce their water holding capacity. For instance, Pulicat Lake has been getting silted up at the rate of about one metre per century. The average depth of about 3.8 metres of the lake prior to the 17th century, when Pulicat Lake served as a natural harbour for the Dutch, is reduced to less than a metre today. This can be attributed to the loads of silt brought in by rivers and streams and also the closure of mouths of the lake.

 

Invasive alien species

 

Many of the water bodies in sanctuaries are invaded by Invasive Alien Species like Prosopisjuliflora and Ipomeacarnea. Prosopisjuliflora actively takes up water from the tanks/lakes and release into the atmosphere through evapotranspiration depleting the water body. Ipomeacarneais a fast invader and tends to replace native vegetation of the water bodies.

 

Land use changes

 

The agricultural lands in the vicinity of sanctuaries like Vedanthangal and Karikili situated adjacent to urban areas are increasingly being converted into real estate plots and sites, thus decreasing the feed availability for the avifauna.

 

Insufficient food availability in the lakes and tanks

 

African catfish, an invasive fish owing to its ability to thrive even in hardy anaerobic conditions has invaded many water bodies. It is a voracious feeder and eradicates most of the native fish population in the water body rendering it unsuitable for birds. Periodical culling of African catfish during summer months and release of fingerlings of native fish in the water bodies would be required.

 

Potential threat of poaching

 

The threat of poaching of birds always looms around the sanctuaries. There are areas like Vedanthangal where there is totally no poaching in the tank. But, birds do not always stay in the tank and move out for feeding during the day time when they fall prey to poachers. Controlling poaching in places like Oussudu which share interstate boundaries is all the more challenging.

 

Grazing

 

When water recedes from the tanks/lakes during summer, the cattle of the villagers living around the sanctuaries use the areas for grazing. Grazing alters plant communities inside the area by trampling of natural regeneration, spread of weeds and diseases in the area.

 

Other than the above, the following are other important challenges in the management of bird sanctuaries which impede the conservation of Avifauna in the State of Tamil Nadu,

claiming for rights in the tank/sanctuary;

 

Future Road Map

 

Identifying sustainable solutions for water scarcity

 

It is absolutely important to take efforts to retain and harvest rain water in the tanks/lakes. Rain water harvesting structures and mechanisms can be created in places wherever possible. Alternate sources of water from adjacent water bodies can be identified for permanent solutions. Holistic approach towards arriving at solutions for water stressed areas should be emphasized like restoring entire wetland complexes rather than individual water bodies. Extensive infrastructure developments and degraded flowing water systems like rivers and streams have resulted in shrinking of rivers and thinning of water flow. Reduced fresh water inlet into brackish water bodies like Pulicat have led to transformations in water quality like salinity adversely affecting the various aquatic life forms and the dependent avifauna.

 

Satellite water bodies in the periphery of the sanctuaries could be improved in terms of water availability and food for birds to provide beneficial habitats.

 

Community Participation in Conservation

 

The local community could be coordinated by forming of eco development committees to bring in community participation and a sense of belongingness and responsibility in conservation. Site specific eco-tourism initiatives could be formulated keeping the local carrying capacity in consideration. The benefits arriving out of these initiatives could be shared among the community as an appreciation for their efforts in conservation for ensuring sustainability of participatory initiative in conservation

 

Research and monitoring

 

Scientific studies and research are insufficient pertaining to individual bird habitats. Sponsored programmes in specific areas of interest could be thought of to encourage more knowledge inflow. Technological advances available in the field of conservation should be made use of effectively.


Recognition

 

Wetlands qualifying the criterions of Ramsar site convention could be identified and efforts taken to get them declared as Ramsar Sites which will bring international focus on these wetlands providing new impetus to wetland conservation.