Knobbly knees emerge from the murky depths of the earth, threatening to trip me up if I don’t keep my eyes firmly on the ground. There is the strong odour of desiccating organic matter – leaves and bark and fruits and living things that came to rest in this muddy soil well before we humans set foot on this land. The steady gurgle of the small stream keeps me sane, else this dark patch of dense canopy rings with the calls of frogs and 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 the way of my clumsy feet only to land mere feet away, poised for a second leap. I nearly slip on the mossy rocks underfoot, choosing to walk through the rushing stream rather than risk the unknown murky depths of the swamp around me.

Welcome to one of the most primitive ecosystems in the tropical world, the Myristica swamp. One of many categories of freshwater swamps, these ancient swamp forests are found in the Western Ghats of India, the Andaman and Nicobar Islands, and in the hills of Meghalaya. Myristica swamps are dominated by members of the flowering plant family Myristicaceae, which has 18 genera and 300 species across the tropics. Four of these genera – Horsfieldia, Gymnacranthera, Knema, and Myristica – and 15 species of Myristicaceae are found in India. The Western Ghats have three genera and five species of Myristicaceae. Two species – Gymnacranthera canarica and Myristica fatua var. magnifica – are exclusively restricted to these swamps. M. malabarica is found occasionally in swamps and predominantly in the wet evergreen forests. Members of this family, a type of wild nutmeg, exhibit similar characteristics; they are shade-tolerant evergreen trees with pinkish-red resinous sap in the bark with simple, dark-green, alternate leaves. 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 in these swamp forests, soaking the earth and forcing the flora and fauna here to adapt to a wet existence. Myristica trees are characterised by stilt roots (see image on the right) that grow above the ground, allowing the trees to perform functions such as transpiration, photosynthesis, and toxin removal despite a waterlogged environment. The trees have a thin, moist bark and large leaves, enabling them to get rid of water easily.

Like most wetlands in India today, these swamp forests face various anthropogenic threats. In the 1970s, Myristica spp. were leased to plywood industries as the light wood of M. fatua was considered useful for matches and packing cases. Swamps are often drained and converted into plantations for areca palm and teak or repurposed as paddy fields. In Uttara Kannada district, studies have found that 17 out of 51 observed swamps face extinction due to repurposing for agriculture. Out of the remaining swamps, 21 face heavy disturbances including tree felling, girdling, prescribed burning, and clearance of groundcover. In certain Myristica swamps, a major issue is the diversion of water for agricultural 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 swamp draining causes higher instances of surface water runoff, leading to flooding and erosion downstream in the monsoon season and leaving behind dry streambeds during the rest of the year. This also reduces the ability of the soil to absorb and retain water, leading to declining soil quality and agricultural impacts.

Swamps provide ecosystem services to humans:

Myristica swamps provide a plethora of tangible and intangible ecosystem services. Swamps are placed low in watershed topography, with the roots of the swamp lying below the water table. Thus, they can effectively channel runoff into the groundwater supply, thereby stabilizing 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. Another ecosystem service provided by Myristica swamps is water quality regulation; wetlands serve as nature’s wastewater treatment plants. Chemicals and nutrients enter wetlands through surface water and groundwater inflows, while major inorganic nutrients (nitrate, ammonium, phosphorous) enter these systems from agricultural runoff. Wetland plants absorb nitrogen in the form of nitrate while excess nitrogen is lost to the atmosphere as nitrogen gas. Swamps are particularly adept at filtering out heavy metals and phosphorous; pesticides and metals remain attached to the sediment floor, maintaining downstream water quality. Such wetland ecosystems also hold high biological value, providing habitat to a plethora of species ranging from micro-invertebrates to mammalian fauna. Swamps also provide medicinal plants used in traditional medicines, creating an economic rationale behind their conservation.

Often, Myristica swamps are venerated as sacred groves by the tribes and villagers that live nearby. By the cool waters of the Sharavati River is an ancient swamp forest nestled in 25 square kilometres of river valley. Known as Kathalekan, this reserved forest has preserved relic species of Myristica spp., gurjan (Dipterocarpus indicus), and kere neerilu (Syzygium travancoricum). Kathalekan has been preserved by local communities and worshipped for centuries, with devotees visiting the grove during Sankranti in January, Adri Mali in June, and Diwali in October. The grove has its own presiding deities, Chowdi (the mother goddess), Bhootappa (the father god), Yakshi bana and Nagara bana. Its religious import, as well as the water it supplies to the surrounding villages, are the key reasons for Kathalekan’s continued existence in a world where forest cover is continuously shrinking. While in the past, the inherent respect for sacred groves maintained these patches of swamp forest, today’s devotees are motivated towards conservation by a fear of the wrath of the residing gods of the grove. Locals in Kathalekan believe that stealing from the grove will bring bad luck and ill health to the wrongdoer. Although human-centric in nature, these fears have helped groves such as Kathalekan to survive in a rapidly- changing world.

Myristica swamps provide habitat for endangered endemic fauna:

My first Myristica swamp visit was near Sirsi, in the district of Siddapur, where paddy and arecanut plantations were the predominant land use. Bordering the sheltered Myristica swamp that I visited were eight to ten homes, most of which managed the arecanut plantations that formed a leafy circle around the swampland. To get to the swamp, we had to cross through the plantations, hike up a steep curving path carved into the hillside, and then climb down a precarious muddy slope – made more treacherous by incessant rains – past the rotting skeleton of an unfortunate bonnet macaque until the leeches began to drop down on our bare skin. The leeches, in retrospect, were the best indicator of our arrival in the swamp. They clung to my bare legs like persistent little commas,  refusing to let go despite my flicks and tugs until they were drunk on my blood. Wading through the fast-moving stream did nothing to dislodge them.

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 for reptiles and amphibians than recorded from outside the swamps. The swamps are estimated to contain 23 percent of butterflies, 11 percent of spiders, 8.4 percent of fish, 50 percent of amphibians, 20 percent of reptiles, 26.6 percent of birds, and 6.6 percent of mammals found in the state of Kerala. Of the recorded wildlife, 16.3 percent are endemic to the Western Ghats landscape while 24.2 percent of vertebrate species are listed on the IUCN Red List of Endangered Species. Perhaps the highlight of my visit to a Myristica swamp was an encounter with a skilfully- camouflaged Malabar pit viper (Trimeresurus malabaricus) on the knotted roots that kept both the snake and I out of the murky water.

A little-known inhabitant of Myristica swamps is the endemic dancing frog (family Micrixalidae). Typically, frogs within this family occupy high-altitude shola forests, wet evergreen forests, Myristica swamps, and, occasionally, secondary forests. Two species – Micrixalus kottigeharensis and M. saxicola – have been recorded by scientific studies from patches of relic swamp forests in the Western Ghats landscape, with M. kottigeharensis entirely restricted to Myristica patches. These frogs are known as “dancing” frogs due to their peculiar habit of waving their feet to attract females during the breeding season. This is called “foot flagging” behaviour; males will tap their hindleg and extend it, repeating this behaviour until reciprocated by prospective mates. This behaviour is also used to warn away rival males. The discovery and subsequent studies on this species have important implications for conservation in India given that as many as seven species in the genus Micrixalus are found outside of protected areas, which are the cornerstone of the Indian conservation movement.

Further research is required to understand these delicate ecosystems:

Myristica swamps have a high watershed value and thus face the path to 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. Swamps, like other wetlands, are known sinks for carbon; preserving these wetlands 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 the conservation of these relic forests. 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?

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This post is a longer version of my article “Who will save the swamps?” published in the Deccan Spectrum. You can find the shorter version by clicking this link. 

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Links to Explore:

To learn more about some really cool research on the dancing frog and other amphibians, follow this link to my colleague Madhushri’s blog Girl Gone Birdzz, where she writes more about her research with the Dancing Frog of India project (with ZSL) and about travel/frogs/birds in general.

Here’s an article in Mongabay India by Neha Jain, who also writes about Myristica swamps in the Western Ghats based on her experiences. Click here to read!

Yet another link to an article by Akshit Sangomla in Down to Earth on Kathalekan, one of Karnataka’s most famous sacred relic swamp forests.

Follow this link to see a short video on Kathalekan (Down to Earth, 2018). 

Here is a link to an educational short video by Kerala’s Department of Environment and Climate Change on Myristica swamps.