Myristica swamps, a vanishing ecosystem in Western Ghats

  

          The Hindu DWINDLING WETLAND: The Myristica Swamps in Western Ghats in Kerala. Photo: Special Arrangement

It is now confined to 53 patches in Kerala

Nestled in the deep valleys of the Western Ghats that is home to a rich diversity of flora and fauna are the vestiges of a pristine habitat that could yield precious information about evolutionary biology and climate change.

Scientists from the Centre for Earth Science Studies here and the Agharkar Research Institute (ARI) in Pune are studying the Myristica swamps, a vanishing ecosystem, now largely confined to 53 patches in the Kulathupuzha and Anchal forest ranges and the Shendurney wildlife sanctuary in Kerala.

A study by the ARI scientists, published recently in the journal, Quaternary International, describes the discovery of plant fossils of the ancient Myristica swamps from the Konkan coast.

The fossils, estimated to be 44,000 years old, throw light on the evergreen vegetation along the Konkan coast. The study infers that Konkan lost its wet evergreen forest cover due to the changes in the monsoon pattern.

The Myristica swamps are tropical fresh water swamp forests with an abundance of Myristica trees, the most primitive of the flowering plants on earth. The evergreen, water-tolerant trees have dense stilt roots helping them stay erect in the thick, black, wet alluvial soil.

The swamps are typically found in valleys, making them prone to inundation during monsoon rains. The trees form a fairly dense forest with a closed canopy.

Studies have shown that the swamps, which would have occupied large swathes of the thickly- wooded Western Ghats in the past, are now restricted to less than 200 hectares in the country.

“As of now, the Myristica swamps of the Western Ghats are fragmented, with Kerala holding a major share of this habitat. Leaving aside a few more patches in Karnataka and Goa, this exceptional wetland has almost disappeared from the Indian subcontinent due to the climatic vicissitudes over the last 18,000 to 50,000 years, a period referred to as the Late Pleistocene period,” said K.P.N. Kumaran, CSIR Emeritus Scientist, ARI.

According to C.N. Mohanan, Head, Department of Environmental Sciences, CESS, the swamps could promote better understanding of the influence of climate change on the evolution of plants. “They are living museums of ancient life.”

Dr. Mohanan said human activities posed a major threat to the unique habitat. “Over time, many of the patches of swamps in Kerala have been converted to paddy fields, arecanut plantations or settlements while others were submerged for irrigation projects. There is an urgent need to conserve the remaining swamps.”

Mr. Kumaran said: “These swamps have high watershed value. When they are drained, filled or otherwise disturbed, their water holding capacity is lost, resulting in floods and erosion during the rainy season and dry streambeds the rest of the year.”

The swamps in Kerala provide habitat for a rich diversity of invertebrate and vertebrate species, including amphibians, reptiles and mammals.

A total of 65 tree species and 72 species of shrub- herb combine have been recorded from the swamps. It is estimated that the wetlands contain 23 per cent of butterflies, 11 per cent of spiders, 8.4 per cent of fishes, more than 50 per cent of amphibians, more than 20 per cent of reptiles, 26.6 per cent of birds and 6.6 per cent of mammals in the whole of Kerala.

Of the animals recorded from the swamps, 16.3 per cent are endemic to the Western Ghats and 24.2 per cent of the vertebrates are Red Listed.

Species diversity and species abundance inside the swamps are significantly higher than that recorded from outside, for both reptiles and amphibians.