5 months ago
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Just a few hundred metres away from the Theppakadu-Thorapalli Road, some Adivasi children watch with intrigue as their day’s catch in the Moyar is taken advantage of by what seems to be a floating log. Further inspection reveals that it is, in fact, an apex predator, the mugger crocodile, also known as the marsh crocodile (Crocodylus palustris). Despite people living in such close proximity to these predators, there have been almost no negative interactions.
A stronghold in the State
The river, encompassing the Mudumalai and Sathyamangalam Tiger Reserves, is one of the strongholds of the species in Tamil Nadu. The species, which is known for being shy and reclusive and listed as “vulnerable” by the International Union for Conservation of Nature (IUCN), has had almost no negative interaction with humans in the region for decades, says R. Arumugam, a former wildlife researcher, who worked with the Madras Crocodile Bank Trust and Centre for Herpetology. He recorded 16-20 breeding females during his study along the river in the early 1990s. “The Moyar is home to one of the largest mugger populations in Tamil Nadu,” he says.
What separates the animals in the region from their counterparts elsewhere is their lack of negative interactions with human communities.
Eye-shine count
Based on an eye-shine count, he puts the population of the species along the river during the 1990s at 100-120. The eye-shine count is enumerating the number of crocodiles at night by observing their eye-shine with the help of a torch. “Though each female could lay around 20 eggs during the breeding season, the rate of mortality for hatchlings was extremely high, with only 1% surviving to adulthood,” says Mr. Arumugam.
A more recent study recorded 81 sightings of crocodiles, including adults, sub-adults, and juveniles, indicating that the species was breeding and stable.
Speaking to The Hindu, Samson Arockianathan, one of the lead authors of the paper, ‘Population status of mugger crocodile (Crocodylus palustris) in Moyar River,’ and the manager of the BNHS Vulture Conservation Breeding Centre in Bhopal, says there was an estimated population of 465 mugger crocodiles across Tamil Nadu, and a 1999 survey recorded 178 individuals along the Moyar.
During the survey between 2014 and 2016, Mr. Samson and his fellow researchers recorded 81 sightings of crocodiles along the 36-kilometre stretch of the river between Belmeen Kadavu and Kallampalayam. Mr. Samson believes that the population is stable, thanks to the habitat in the Moyar falling along the highly protected tiger reserves of Mudumalai and Sathyamangalam. “Moreover, the lack of negative interactions between the crocodiles and people is a prime example of human-animal co-existence, and this is primarily owing to the Adivasis’ understanding of living alongside the wildlife,” he says.
Threat from invasive species
Though population estimates vary, threats, if any, are less well-studied. According to Mr. Arumugam, the use of dynamite for fishing along parts of the river posed a threat to crocodiles and other endemic species during the period of his study. “In the years since, highly invasive species of flora, such as Prosopis juliflora, have also become prevalent along the Moyar. This could degrade the nesting sites for the crocodiles.”
Other conservationists have voiced concern over the introduction of invasive species in the river ecosystems. “The Fisheries Department continues to introduce non-native fish into the Nilgiris waterbodies. This could have serious consequences, in the long term, for the crocodiles as well as the other wildlife inhabiting the riverine ecosystems,” says another conservationist.
B. Ramakrishnan, Head of the Department of Wildlife Biology, Government Arts College, Udhagamandalam, calls for a study to identify the crocodile nesting sites along the Moyar so that they can be protected from the advance of invasive species. The Forest Department is aware of the threats posed by invasive flora to the local wildlife. P. Arunkumar, Deputy Director of the Mudumalai Tiger Reserve (Buffer Area), says Prosopis juliflora was removed from around 500 hectares in the MTR over the last few years.
Conservator of Forests (Nilgiris) D. Venkatesh says the Forest Department plans to undertake studies to better understand the species that inhabit the rivers flowing through the tiger reserve. , including the mugger crocodile, humpback mahseer, river otters and endemic fish species. “These studies, which we plan to conduct after a very long gap, will help to formulate strategies to better protect species like the mugger.”
