Who will save the swamps?

Myristica swamps of the Western Ghats, India's most ancient swamp forests, need attention as they face anthropogenic and climate change threats
Last Updated 25 October 2019, 19:30 IST
Amphibian life abounds in Myristica swamps.
Amphibian life abounds in Myristica swamps.
 The stilt roots of a Myristica tree allow it to respire above the standing water.
 The stilt roots of a Myristica tree allow it to respire above the standing water.
a Malabar pit viper rests on the tangled roots of a Myristica tree.
a Malabar pit viper rests on the tangled roots of a Myristica tree.

Knobbly roots threaten to trip me if I don’t keep my eyes firmly on the ground.

There is the strong odour of desiccating organic matter — leaves, bark, fruits and living things that came to rest in this muddy soil well before we humans set foot here.

The gurgle of the stream guides me through this dark patch of dense canopy that rings with the calls of cicadas. A thrush flits by and butterflies dance close to the bubbling stream. A damselfly hovers on delicate fibrous wings above a budding flower.

This swamp radiates a sense of both life and death. As I make my way forward, my floaters making sucking sounds in the wet soil, a Malabar pit viper slithers away through the tangled roots. Frogs leap out of my way as I slip on the mossy rocks underfoot, choosing to walk through the rushing stream rather than risk the murky depths of the swamp around me.

Welcome to one of India’s most ancient swamp forests: the Myristica swamp.

Myristica swamps are found in the Western Ghats, Andaman and Nicobar Islands, and Meghalaya.

Members of the flowering plant family Myristicaceae, which has 18 genera and 300 species across the tropics, dominate these swamps. This family, a type of wild nutmeg, has shade-tolerant evergreen trees with pinkish-red resinous sap in the bark, and simple, dark-green, alternate leaves.

Four genera (15 species) of Myristicaceae are found in India, of which three genera (five species) are endemic to the Western Ghats. Two species — Gymnacranthera canarica and Myristica fatua — are exclusively restricted to Myristica swamps. These vanishing swamp forests are widely regarded as ‘living fossils’ due to their primitive origins. Indeed, Myristica is the oldest flowering tree genus in the world!

Life in a flooded world

Water flows perennially here, soaking the earth and forcing both flora and fauna to adapt to wet conditions.

Myristica trees have stilt roots growing above the water level, facilitating transpiration, photosynthesis, and toxin removal, with a thin, moist bark and large leaves that shed water easily.

Like most wetlands in India today, these swamps face various anthropogenic threats. In the 1970s, Myristica species were leased to plywood industries to make matches and packing cases, while today, swamps are drained and converted into areca palm and teak plantations or repurposed as paddy fields.

Studies in Uttara Kannada district reveal that 17 out of 51 observed swamps face extinction due to repurposing for agriculture.

In certain Myristica swamps, a major issue is the diversion of water for plantations and check-dams for potable water, which is fatal for these swamp-dwelling trees that have evolved to survive in perennially-flowing water.

The draining of swamps has grievous implications for the larger ecological balance. Research conducted by Chandran and Mesta in 2006 found that draining swamps causes higher instances of surface-water runoff, leading to flooding and erosion downstream in the monsoons, leaving behind dry streambeds the rest of the year. The ability of the soil to absorb and retain water is reduced, leading to declining soil quality and agricultural impacts.

Myristica swamps benefit surrounding human communities as well. Swamps are placed low in watershed topography, with the bottom of the swamp below the water table.

This effectively channels runoff into the groundwater supply, stabilising the water table and acting as a natural flood-barrier during periods of heavy rainfall. Standing water in swamps seeps into underground aquifers, a layer of semipermeable rock that holds reserves of water, and replenishes the available water supply.

Myristica swamps regulate water quality, serving as nature’s wastewater treatment plants.

Chemicals and pollutants enter wetlands through surface water and groundwater inflows, while major inorganic nutrients (nitrate, ammonium, phosphorous) enter these systems from agricultural runoff.

Wetland plants absorb nitrate; excess nitrogen is lost to the atmosphere. Swamps effectively filter out heavy metals and phosphorous with pesticides and metals binding to the sediment floor, maintaining downstream water quality. Such wetland ecosystems also hold high biological value, providing habitat to various species. Swamps provide medicinal plants used in traditional medicines, creating an economic rationale behind their conservation.

Saviour ecosystem

Often, Myristica swamps are venerated as sacred groves by the surrounding tribal villages. Kathalekan, an ancient swamp forest, covers 25 sq km of the Sharavati river valley. This reserved forest has preserved relics of Myristica species, gurjan (Dipterocarpus indicus), and kere neerilu (Syzygium travancoricum).

Kathalekan has been worshipped by local communities for centuries. The grove has its own presiding deities visited by devotees during Sankranti, Adri Mali, and Diwali. Locals in Kathalekan believe that stealing from the grove will bring bad luck and ill- health to the wrongdoer. Such fears, and the perennial water resources, have helped such groves survive in a rapidly-changing world.

My first Myristica swamp visit was near Sirsi, in Uttara Kannada district, where paddy and arecanut reign supreme. Bordering the sheltered swamp were eight homes, most of which managed the surrounding arecanut plantations.

To get to the swamp, we had to cross the plantations, hike up a steep curving path carved into the hillside, and then climb down a precarious muddy slope in incessant rain, past the rotting skeleton of an unfortunate bonnet macaque. The leeches heralded our arrival to the swamp, clinging to our legs like persistent commas.

Myristica swamps have incredible biodiversity and a rich species history. Studies from swamps in Kerala by researchers from the Kerala Forest Research Institute, Thrissur, recorded 65 tree species, 72 species of shrubs and herbs, and higher levels of species diversity and abundance of reptiles and amphibians than those recorded from outside the swamps.

These swamps contain approximately 8.4% of fish, 50% of amphibians, 20% of reptiles, 26.6% of birds, and 6.6% of mammals found in Kerala. Of the recorded wildlife, 16.3% are endemic to the Western Ghats landscape while 24.2% of vertebrate species are listed on the IUCN Red List of Endangered Species.

The discovery of and subsequent studies on a little-known inhabitant of Myristica swamps, the endemic dancing frog (family Micrixalidae), reveals important implications for conservation in India. Seven species in this frog family survive outside of protected areas, which are the only legally-protected habitats in India.

Protecting habitats outside of national parks is key to saving India’s rare amphibian life.

More research

Myristica swamps have a high watershed value yet face the threat of extinction. Without further scientific assessment, it is difficult to predict how climate change and anthropogenic influences will affect these ecosystems, and whether the loss of swamps will create further complications in attempts to prevent a global temperature rise.

Wetlands are known sinks for carbon; their preservation allows for the sequestration of atmospheric carbon, thus regulating the global climate. The scale at which such regulation occurs must be studied further in order to create a stronger case for their conservation.

The Indian Forest Service has included many freshwater swamps under the category of reserved forest to prevent conversion by farmers into plantation, but is the law alone enough to preserve India’s vanishing swamp forests?

(The writer is Research Associate, Ashoka Trust for Research in Ecology and the Environment, Bengaluru.)

(Published 25 October 2019, 19:30 IST)

Follow us on