How wetlands are the nurseries of life

Four main kinds of wetlands have been defined: marshes, swamps, bogs and fens. Marshes – usually found at the edges of lakes, generally support herbaceous plants – grasses, rushes and reeds; swamps support woody plants, bogs accumulate peat – dead plant matter like sphagnum mosses – and fens are alkaline bogs enriched by mineral-rich water.

A high water table ensures these areas flood easily – and retain water perennially or seasonally. The water and soils are usually oxygen-free and the plants that grow are specifically adapted to deal with this. Wetlands may get their water from different sources – for instance, tidal wetlands from oceanic tides, and estuaries from a mixture of tidal and river water, floodplains from overflowing rivers, springs from groundwater seepage and bogs et al from rainfall or snow melt.

So, of what use are these sometimes smelly, muddy, glutinous places, humming and thrumming with stinging and biting insects, not to mention the odd hungry crocodile? Well, wetlands (found everywhere except Antarctica) are supposed to be the most richly bio-diverse places on earth and according to some, even more productive than a tropical rainforest. They support a bewildering and kaleidoscopic variety of life – whether of plants (some of which flower underwater), insects – dragonflies, bugs, beetles; amphibians – turtles; fish of which 200 new freshwater species are being discovered every year; reptiles – crocodiles and snakes; birds – waterfowl and waders, (300 species of birds are wetland dependent in India alone), and mammals such as beavers not to mention a host of smaller creepy-crawlies and algae.  They are nurseries of life – especially for tropical fish. And they are vital for us too: rice, which is a staple for half the world’s people – is a wetland plant.

In addition, wetlands work like humongous sponges, soaking up and storing rainfall and leaching it out gradually through the year; they also act like massive filtration plants, cleaning the muck we pour into them, and floodplains prevent ruinous flooding (the destruction of floodplains has had disastrous effects in cities like Chennai). Mangrove swamps tame and gentle even ferocious tidal waves and storm surges. On the debit side, some marshes do exhale methane (which was called ‘marsh gas’) and nitrous oxide – which are both greenhouse gases. But on balance, wetlands really do a lot of the hard, heavy and dirty lifting in order to keep ecosystems ticking over – and we seem hell-bent on destroying them. 

It’s believed that our “anti-wetland” activities have put under the guillotine 17 per cent of waterfowl, 38 per cent of mammals (which are freshwater dependent), 33 per cent of freshwater fish, 26 per cent of amphibians, 72 per cent of freshwater turtles, 86 per cent of marine turtles, 43 per cent of crocodilians and 27 per cent of coral reef building species – not an enviable scorecard. Asia is said to be losing 500,000 hectares of wetland every year and it is thought we’ve already destroyed 87 per cent of our existent wetlands, the world over. 

Some of our most wonderful wetlands are Pulicat Lake in Andhra Pradesh, Chilika in Odisha, Sambhar in Rajasthan, the Gulf of Kutch, the Ganges and Brahmaputra deltas, and of course the magnificent Sundarban mangrove swamps. And it’s not all doom and gloom: the Keoladeo National Park, aka Bharatpur – is a man-made and managed wetland and one of the best water-bird sanctuaries in the world (agreed it was devised as a hunting preserve and its destruction was plotted by political elements but then the “Bird Man of India”, naturalist Salim Ali stepped in), and right here, in Delhi, the Yamuna Biodiversity Park is a shining example of what can be done: Given a barren patch of land near the river, which resembled a tank-testing ground, scientists of the Centre for the Environmental Management of Degraded Ecosystems, University of Delhi, led by the redoubtable professor CR Babu and Dr Faiyaz Khudsar suspected, by the kind of grasses they found here, that the area had once been a natural wetland. This meant that the water table was high, and, which in turn, meant that with proper scientific planning and planting it could be revived: The result? Two water bodies – shallow and deep – which attract waders and divers by the hundreds – and the 30 to 35 different riverine ecosystems planted to replicate those found in the Yamuna basin encouraging resident nesters, and attracted mammals from wild-boar, nilgai, and porcupine to that prime apex predator, the leopard (which alas had to be exiled).

Unfortunately, we still harbor this insane mania to “develop” our water-bodies, river-banks, lakesides and floodplains (where marshes and swamps are born and thrive) and to pave them over to “civilize” them, so there is no glutinous mud or squelch or bulrushes or reeds or dragonflies or wild duck, geese and herons to be seen anywhere. Also, we swear to clean them up every World Wetland Day, and then spend the rest of the year, vomiting raw sewage, and toxic chemical wastes into them without a second thought. And then, when our cities drown in the monsoons, because we’ve built shopping malls on the floodplains, we dare to wonder why…