Wild Elephants in the Nilgiris help seed dispersal of fruit bearing plants: reveals new study

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Elephant herds in Silent Valley National Park in Western Ghats of Kerala
(Photo Courtesy: N P Jayan)

Wild tuskers in Southern Western Ghats are just like birds. Not that they can fly, but like their winged friends, they play a crucial role in the seed dispersal of some plant species found in this rare biodiversity hotspot, says researchers who studied the seed dispersal role of elephants here.According to their study, Asian elephants (Elephas maximus) are important seed dispersing agents of some fruit bearing plants in the semi-deciduous, thorny forests of the Nilgiri Biosphere Reserve, the oldest biosphere reserve in India which lies in the Western Ghats.

By examining the fruit seeds and remnants in elephant dung piles in the study areas, the researchers found that this biggest terrestrial animal plays a key role in the seed dispersal of at least eight different plant species found in the area like Acacia intsia (Twisted Acacia), Artocarpus heterophyllus (Jack Fruit), Bauhinia racemosa (Bidi Leaf Tree), Grewia hirsuta (Kukurbicha), Grewia tiliifolia (Dhaman), Mangifera indica (Mango), Tamarindus indica (Tamarind) and Ziziphus mauritiana (Indian jujube). Among these eight, Wild Tamarind and Twisted Acacia are the favorite fruit of the tuskers, since their presence was significantly more in the dung piles than the other six species, says the study which is published in the Journal of Threatened Taxa.

Earlier research in Asian and African forests have shown that elephants are a very effective seed dispersing agents. They devour huge amount of fruits and carry the seeds to long distances from the parent tree with their behavior of moving to wide-ranging areas. Moreover, seeds are defecated intact. It is also observed that the dung piles often provide a nutritious medium for seed germination.

Fruit Diet of the Pachyderms in the Nilgiris

The study has also revealed some interesting insights into the food habits of the wild elephants in Nilgiris. According to the researchers, elephants in the area consume more fruits during dry season when compared to the wet monsoon season. “Seeds and other fruit parts appeared in the dung piles significantly more frequently during the dry season than in the wet seasons”, says the study.

Moreover, tuskers prefer a fruity diet more in the thorny forests, than in a moist deciduous area, shows the results of the study. The study also confirms the sometimes notorious truth of the tuskers’ irresistible temptation for mango and jack fruits when they are in moist deciduous areas in NBR. Remnants of both of these fruits were frequently found in the dung piles from moist deciduous areas. Often, fruiting jack fruit trees are blamed for wild elephants raiding villages in the forest fringes of NBR.

However, pachyderms have dislikes for certain items in their fruits menu, says the study. Fruits of Z. mauritiana are less preferred by these animals, as indicated by the lower presence of these fruit remnants in the dung piles, despite the wide presence of the plant in the forests of NBR.

But don’t misunderstand that the wild elephants in Western Ghats consider fruits as their favorite item like their African and Malayan counter parts, reminds the researchers. Grass species like bamboo are the first preference for tuskers in these areas. Fruits are second or third in the list. “Elephants consume a lesser number of fruit species in the tropical dry forests of Nilgiri Biosphere Reserve than in the rainforest habitats of Asia and Africa”, points out the study.

Asian Elephant Population in the Nilgiris

The study was carried out in Mudumalai Wildlife Sanctuary which is presently a Tiger Reserve, Nilgiri North, Sathiyamangalam and Coimbatore forest divisions, Bandipur Tiger Reserve and Wayanad Wildlife Sanctuary which all come under Nilgiri Biosphere Reserve.

According to the figures of the last elephant census, the area holds the one of the largest population of Asian elephants in the world, with approximately 4,500–5,800 individuals.

During the study period, the research team extensively followed elephant herds and bulls in these areas. According to the researchers, they have collected fresh dung piles whenever defecation was observed. On a total, they have examined 455 elephant dung piles during the whole study period.

Nagarajan Baskaran and Ajay A. Desai of  Bombay Natural History Society have co-authored the study.

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New Stone Loach Species Discovered from Silent Valley National Park

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Far-famed for the silence of the cicadas(though now they are aplenty) and the endemic Lion Tailed Macaque, the Silent Valley National Park in Kerala, India has just got another endemic organism to its credits, when researchers identified a new species of stone loach from Kunthippuzha which flows through the National Park.

Balitora Jalpalli, new stone loach species  from Kunthi River in Silent Valley National Park
(Image Credit: Josin Tharian)

According to a study published in the Journal of Threatened Taxa, the new species of Stone loach differs from its close relatives in head length, caudal peduncle depth, maximum head width and in the number and pattern of bands on the dorsal side.  It has a different number of ventral fin rays and pectoral fin rays than its close relatives also.

Water Lizard of Kunthi River

The newly identified fish belongs to the genus Balitora, and is named as Balitora Jalpalli. According to the authors of the study, the fish was named so for its lizard like characteristics. 'Jal’ means Water and ‘Palli’ means Lizard in the local language, making ‘Jalpalli’ equivalent to ‘Water-lizard’. It “refers to the lizard like appearance of the fish, and its habit of clinging to the rocks in fast flowing streams,” says the study. According to the researchers who have conducted the study, the newly identified stone loach can be commonly called as Silent Valley Stone Loach as well.

The researchers were able to spot the fish from Valleparathodu, near Poochippara from the Kunthi River which is a tributary of Bharathappuzha, a major river in the state. According to the study, this habitat is a high altitude stream which is usually inhabited by other fishes like Mesonoemacheilus remadevii, Homaloptera pillai, Bhavania australis and Garra menoni.

Genus Balitora consists of 11 to 12 species of fishes so far among which two were reported from Kerala. The new species discovery makes the Balitora strength in state to three.

Conservation Significance of Western Ghats Rivers

The identification and description of B. Jalpalli from Western Ghats comes on close heels to a similar species discovery from Krishna River, yet another major river in Western Ghats. Researchers have identified and described another species of Balitora - Balitora Laticuda - from Krishna River in 2012. These new discoveries point out to the rich but unexplored aquatic fauna of Western Ghats Rivers and the exigency to conserve the freshwater ecosystem in the region.

However, habitat destruction is rampant in Western Ghats Rivers due to anthropogenic pressure. According to the study, immediate conservation efforts and taxonomic explorations should be carried out in the area to unearth the unraveled marvels of biodiversity here. “The description of one more species of freshwater fish from the Western Ghats reiterate our views that the ichthyofauna of the region continues to be poorly known and is in need of increased exploratory surveys and associated taxonomic research”, say the researchers.

Rajeev Raghavan and Anvar Ali of Conservation Research Group (CRG), St. Albert’s College, Kochi,

Josin Tharian of Laboratory for Systematics and Conservation, Department of Zoology, St. John’s College, Anchal, Shrikant Jadhav, Zoological Survey of India (ZSI) and Neelesh Dahanukar of Indian Institute of Science Education and Research (IISER) co-authored the paper in the Journal of Threatened Taxa..