397
inflow of water from the estuary throughout the year, but the water level and its
quality is influenced by the waves and tidal actions (Ramanujam 2005).
12.3.3 Yedayanthittu Estuary
Yedayanthittu estuary (12°12′N – 12°15′ E and 79°56′N – 80°0′ E) situated about
3 km to the northeast of this wetland. This estuary has large areas of inter-tidal mudflats, but only small relicts of the once extensive mangrove forests now remain.
There are some 500 ha of saltpans alongside the estuary immediately to the north of
the Marakkanam road bridge across the channel from Kaliveli wetland. Aforetime
25 years ago, the entire area was heavily forested, but at present most of the forest
area has been removed, the reservoir and the estuary are currently bounded with
cultivation and scrubby thorn woodland. There are some stumpy sand dunes adjacent to the channel linking the tank to the estuary.
12.4 Diversity of Flora and Fauna
Kalivelli wetland is a haven for hundreds of species of flora and fauna, Kalivelli
wetland nurtures several species of birds, fish, reptiles and mammals. The common
aquatic vegetation plants in the study area are Aponogeton natans, Eichhornia
crassipes, Hydrilla verticillata, Limnophyton obtusifolium, Monochoria vaginalis,
Vallisneria spiralis, Aristida adscensionis, Chloris barbata, Chloris Montana,
Polygala arvensis, Lindernia crustacean, Scoparia dulcis, Waltheria indica, Acacia
nilotica, Alternanthera sessilis, Bacopa monnieri, Coldenia procumbens, Cyperus
distans, Eclipta prostrate, Heliotropium indicum, Hygrophila angustifolia, Ludwigia
perennis, Phyla nodiflora, Polygonum barbatum, Typhya angustata, Prosopis juliflora, Barringtonia, Acacia nilotica, and Avicennia marina (Ramanujam 2005).
Information regarding the Ichthyofaunal diversity of this wetland is still very
meager; Ramanujam (2005) reported 42 species of fishes representing 25 families
and 09 orders. Out of these 42 species, 6 were confined to the flood plain, 19 were
estuarine and 17 occurred in both floodplain and creek. Both anadromous and catadromus species were present. Balachandran (1994) and Perennou and Santharam
(1990) thoroughly studied the avifauna richness of this wetland. About 179 species
of birds have so far been recorded in this wetland. Of the 179 species, 30 are shore
birds and waders, while 13 species are ducks. During March–April, the wetland
attracts pelicans, herons, egrets, storks and ibises. Besides these the wetland serves
as an important corridor for the migratory birds they visit the Point Calimere Bird
Sanctuary during winter. Large congregation (in thousands), of wetland birds can be
seen from October to March, since the ecological conditions of the wetland during
this period are highly suitable for the migratory birds. Nevertheless, this wealthy
ecosystem has presently come under threat due to land encroachments, increasing
shrimp farms and other anthropogenic activities. Because of this, there is an urgent
12 Assessment of Anthropogenic Threats to the Biological Resources of Kaliveli…
inflow of water from the estuary throughout the year, but the water level and its
quality is influenced by the waves and tidal actions (Ramanujam 2005).
12.3.3 Yedayanthittu Estuary
Yedayanthittu estuary (12°12′N – 12°15′ E and 79°56′N – 80°0′ E) situated about
3 km to the northeast of this wetland. This estuary has large areas of inter-tidal mudflats, but only small relicts of the once extensive mangrove forests now remain.
There are some 500 ha of saltpans alongside the estuary immediately to the north of
the Marakkanam road bridge across the channel from Kaliveli wetland. Aforetime
25 years ago, the entire area was heavily forested, but at present most of the forest
area has been removed, the reservoir and the estuary are currently bounded with
cultivation and scrubby thorn woodland. There are some stumpy sand dunes adjacent to the channel linking the tank to the estuary.
12.4 Diversity of Flora and Fauna
Kalivelli wetland is a haven for hundreds of species of flora and fauna, Kalivelli
wetland nurtures several species of birds, fish, reptiles and mammals. The common
aquatic vegetation plants in the study area are Aponogeton natans, Eichhornia
crassipes, Hydrilla verticillata, Limnophyton obtusifolium, Monochoria vaginalis,
Vallisneria spiralis, Aristida adscensionis, Chloris barbata, Chloris Montana,
Polygala arvensis, Lindernia crustacean, Scoparia dulcis, Waltheria indica, Acacia
nilotica, Alternanthera sessilis, Bacopa monnieri, Coldenia procumbens, Cyperus
distans, Eclipta prostrate, Heliotropium indicum, Hygrophila angustifolia, Ludwigia
perennis, Phyla nodiflora, Polygonum barbatum, Typhya angustata, Prosopis juliflora, Barringtonia, Acacia nilotica, and Avicennia marina (Ramanujam 2005).
Information regarding the Ichthyofaunal diversity of this wetland is still very
meager; Ramanujam (2005) reported 42 species of fishes representing 25 families
and 09 orders. Out of these 42 species, 6 were confined to the flood plain, 19 were
estuarine and 17 occurred in both floodplain and creek. Both anadromous and catadromus species were present. Balachandran (1994) and Perennou and Santharam
(1990) thoroughly studied the avifauna richness of this wetland. About 179 species
of birds have so far been recorded in this wetland. Of the 179 species, 30 are shore
birds and waders, while 13 species are ducks. During March–April, the wetland
attracts pelicans, herons, egrets, storks and ibises. Besides these the wetland serves
as an important corridor for the migratory birds they visit the Point Calimere Bird
Sanctuary during winter. Large congregation (in thousands), of wetland birds can be
seen from October to March, since the ecological conditions of the wetland during
this period are highly suitable for the migratory birds. Nevertheless, this wealthy
ecosystem has presently come under threat due to land encroachments, increasing
shrimp farms and other anthropogenic activities. Because of this, there is an urgent
12 Assessment of Anthropogenic Threats to the Biological Resources of Kaliveli…