Home Conservation Field Reports Relic Forest, Tadpoles And Foot-Flagging Frogs

Relic Forest, Tadpoles And Foot-Flagging Frogs

Relic Forest, Tadpoles And Foot-Flagging Frogs

Priti. H. writes about her first volunteering experience with a biodiversity research project, which led her into a wet world of very unique frogs and tadpoles in the Myristica swamps of the Western Ghats’ Kathalekan forest.

Micrixalus frogs have been documented using vocal and visual communication aids. They croak by inflating silver-white vocal sacs and recent studies reveal that the unique foot-flagging behaviour seen here is also used to defend perching sites. Photo: Dr. K.V. Gururaja.

As you journey from Bangalore towards the Western Ghats, the traffic and dust of the concrete jungle slowly give way to small towns, agricultural fields, serene lakes and finally, lush, verdant forests. This is what I found myself doing in the monsoon of 2010, as I headed towards Jog, a small town nestled in the heart of the Sahyadris.

This was my first visit to the Jog Falls area as part of a biodiversity research project though I had visited it as a tourist several times before. But this time I would go beyond the falls to assist a team in the wild forests!

We were based in the Sharavathi Nature Camp. It had rained heavily the previous night and the morning mist was hardly conducive to sightings. After a customary stopover at the Jog falls, we headed for Honnavar, stopping some distance away near the Kathalekan forest, where we gathered our paraphernalia and made our way via a small mud path.

Kathalekan (kathale = dark, kan = sacred grove), true to its name, looked menacing, dense and dark. The sun’s rays barely reach the ground through the closed evergreen canopy. Running along the national highway, the forest and its denizens are subjected to honking horns and perpetual traffic noise. On entering Kathalekan, the flowing streams displaced much of the vehicular din. Mysterious and green, the forest is inundated with water all year round, and more so during the monsoon when streams swell up dramatically. In places, however, the streams looked sluggish and gave the impression of swamps with tall trees that sported weird-looking root-outgrowths. We had reached the ‘Myristica swamps’, named after the trees we could see all around us.

The Jog or Gerosoppa Falls on the river Sharavathi, is the second-highest plunge waterfall (253 m.) in India. Photo: Dr. K.V. Gururaja.

KATHALEKAN’S BIODIVERSITY

I am not a botanist, but the different-looking roots in the Myristica swamp fascinated me. Fortunately, we had a plant expert in the team who explained that such roots belonged to two evergreen trees that dominate this swamp forest – Gymnacranthera canarica and Myristica fatua. The former has short, inverted, U-shaped knee roots that appeared like a brown carpet and the latter has long stilt roots. The roots were impressive and our legs became entangled as we tried to walk across them! Evolved to form ‘knee-roots’ the appendages help the tree to cope with the anaerobic conditions of the swamps. Stilt roots also help anchor the trees in the damp wetland soil. Around us were several other endemic evergreen trees belonging to families such as Dipterocarpaceae, Anacardiaceae, Celastraceae and Xanthophyllaceae, to name a few. The highly-endangered Semecarpus kathalekanensis, exclusive to this swamp, was first discovered in this very forest. Locals, we discovered often identified and named trees based on their characteristic features. Gymnacranthera canarica itself is called by locals as ondanki mara as the kneeroots resemble the Kannada numeral 1 (ondanki = one, mara = tree).

The forest is home to diverse flora and fauna, including several Western Ghats endemics. Exploring the swamps, one sees diverse microhabitats where annelids, amphibians, fish, molluscs, reptiles and, birds all find sustenance. Without loss of time, we got down to business… searching for the torrent frog which, unlike most other frogs and toads, is active in the day. Around us the calls of the Malabar Whistling Thrush, the graceful flutters of the Malabar tree nymph, ubiquitous cicadas and the occasional loud calls of Hanuman langurs filled the forest. We knew this forest harboured two more Western Ghats endemics – the Myristica bamboo tail damselfly and the lion-tailed macaque. Much to my delight, we managed to spot the damselfly with relative ease.

Kathalekan is also a haven for snakes, especially Malabar pit vipers. Crossing a stream, I saw one coiled on the rocks, camouflaged on its backdrop of green moss.

Further into the forest, a strange “chi chi chir chir” sound, resembling that of a chirping cricket stopped me in my tracks. That had to be our quarry, the very tiny torrent frog Micrixalus kottigeharensis. When you know where to look, the forest reveals more than people might imagine. Perched on the rocks that studded the forest streams, we saw many individuals. And each time they called, their silver-white vocal sacs gleamed against the green backdrop! As we bent to photograph two individuals, one suddenly lifted its left leg in the air almost as though it was waving to me. That was strange! This behaviour I had never seen before. Fascinated, I kept watch over an extended period of time and discovered the signal being repeated several times, until one of the frogs hopped off the rock onto an adjacent one! A colleague more experienced with torrent frogs than I explained the foot-flagging behaviour.

Gymnacranthera canarica is a dominant tree found in the unique Myristica swamps of the Western Ghats. The U-shaped knee roots enable the trees to deal with the anaerobic conditions in the swamps. Photo: Priti. H.

It seem that acoustic signals tend to get drowned out in habitats such as this, and many animals therefore resort to visual signalling as an alternative mode of communication. A recent paper also suggests that foot-flagging maybe used to defend perching sites. It is believed that the foot-flagging antics may have originated in order to minimise the chances of physical attacks. Predictably, we spent most of our time that day in the company of these incredible rainforest frogs, looking and then looking again at their fascinating foot-flagging antics.

The visit to Kathalekan also presented me the opportunity to observe and learn more about the larval forms of frogs – tadpoles! These young amphibians form the initial stage of the amphibian lifecycle, which metamorphose into adult frogs. We sighted the fish-like tadpoles in the streams though it was difficult to get hold of them for closer inspection, as they would quickly vanish under fallen leaves, sandy substrates and root pockets of the Myristica swamp.

LEARNING ABOUT TADPOLES

Just one volunteering experience got me hooked and in 2012, I took up a project to look into the diversity and distribution of tadpoles in Kathalekan, with help from the Madras Crocodile Bank Trust Herpetologist Research Funding. The search for tadpoles opened a new and underexplored world. The swamp forest’s diverse tadpoles occupied particular microhabitats. Some preferred runs while some stagnant muddy pools, and still others the stream-terrestrial matrix. The feeding habits of tadpoles also varied. Generally, tadpoles fed on algae and decaying vegetation, but some were downright carnivorous. Interestingly, as the microhabitats differed so did body structure. Being adapted to specific habitats, tadpoles offer a unique perspective of their ecology and environment. Identification is difficult compared to the adults, but monitoring tadpole populations is vital for they remain in their chosen habitats longer than adults and offer clues to changes in both landscape and climate.

The fish-like tadpoles of Indirana species are found in swamps that offer the amphibians that magic resource so essential to live – water. Fallen leaves, sandy substrates and root pockets in the Myristica swamp act to protect the tadpoles from predators… and nosy researchers. Photo: Priti. H.

The Myristica swamps are remnants of an ancient past and many such swamps have already been destroyed to make way for the agriculture juggernaut. Kathalekan is one of the few relic forests in the Sharavathi river basin. However, this amazing biodiversity trove is also under attack. Discussions with local people and ecologists who have worked in this region revealed that the National Highway 206 has already divided and fragmented the once-contiguous jungle. Areca nut plantations upstream of the region have destroyed still more forest. And litter is everywhere. I personally noticed human excreta, plastic bags and broken bottles even deep inside the forest. Bathing and open defecation are common sights near the waterfalls in and around what should be a highly protected wilderness. As a researcher, I for one have resolved not to be content with merely observing and commenting. With other researchers, I intend to help protect the wilderness that I have learned so much about. And I am confident that my quest will have the greatest hope of success if somehow we are able to unite the strengths and energies of the Forest Department and local communities.

Author: Priti. H., First appeared in: Sanctuary Asia, Vol. XXXIV, No. 3, June 2014

 
 
 

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Mallika Narvekar

June 24, 2014, 01:21 PM
 This is such a great article. You find the most beautiful, pristine forests across our country. Let hope they stay untouched and the new governments development plan doesn't destroy them.