Friday November 15, 2019
Home Lead Story Thailand: Ele...

Thailand: Elephants Aid in Spreading Fruit Seeds

Based on the diets and habits of mammals, scientists found that elephants are the best allies for the Thai Annonaceae tree to spread its seeds.

0
//
Elephants
Many Elephants Die Due To Trains, Trucks. Pixabay

Massive fruit trees in the Thailand evergreen forest need Elephants to help spread their seeds, according to a new study.

Based on the diets and habits of mammals, scientists found that elephants are the best allies for the Thai Annonaceae tree to spread its seeds.

In the diverse environment of Khao Yai National Park, there is a complex set of relationships between the plants and animals. Not every species of fruiting tree is an attractive meal to all herbivores. A team of researchers, led by Kim McConkey from the University of Nottingham, set out to study one particular tree, the Platymitra macrocarpa from the family of custard apple trees.

The p. macrocarpa produces 3-to-5-inch fruit that are ripe from May through August. McConkey tracked how often animals visited the trees and ate the fruit, including elephants, bears, monkeys, gibbons and Sambar deer. They measured the animals’ fruit consumption as well as the ensuing seed dispersal and seed viability.

Researchers found the seeds in the dung of some species while others like the Sambar deer regurgitated the large seeds. When asked about tracking animal poop, McConkey admitted, “I’ve got two boys so they just love what I do.”

As expected, the Asian elephants were the major seed dispersers for the p. macrocarpa. Elephants aren’t often seen in the area of the trees McConkey studied, but as she told VOA, “I thought if I’m going to see them feed on any fruit, it’s going to be this one.” Her hunch was borne out in the data, with elephants consuming only 3 percent of the fruit but producing 37 percent of the viable seedlings.

Elephants
The p. macrocarpa produces 3-to-5-inch fruit that are ripe from May through August. VOA

These findings regarding the Asian elephants point to the important role they play in the ecosystem. Jedediah Brodie, chair of conservation in the Wildlife Biology Program at the University of Montana, told VOA that “overhunting in the tropics often drives large animals locally extinct but leaves smaller species like rodents. And this study shows that those smaller animals just are not able to replicate the ecological role of the larger species.”

When looking at the performance of other species, the researchers were surprised by how effective Sambar deer were at dispersing seeds. “Sambar deer generally have quite a bad rap in these forests,” McConkey said. “People think they’re seed predators, but it turns out they actually do disperse a lot of seeds.” While the Sambar deer weren’t quite as effective seed dispersers as gibbons (21 percent), they still produced a respectable 17 percent.

Bruchid beetles were the primary challenge to producing viable seedlings. The beetles, which are known to infest all kinds of seeds and beans, spoiled most of the seeds left exposed on the forest floor. Unlike the regurgitated seeds of the sambar deer, the seeds went through the elephants’ digestive system and were covered by excrement. The seeds were protected from beetles and provided with an effective, natural fertilizer and were able to survive and grow into seedlings.

It is easy to think of animals adapting to their environment through evolution and behavioral change, but we rarely consider the same relationship in the opposite direction. The massive Platymitra macrocarpa has perhaps evolved to provide fruit that appeals to more than one frugivore.

Also Read-Breaking the Law? Sri Lanka Cracks Down on Owners of Elephants taken from Wild

As McConkey told VOA, “The husk of the fruit — it’s like the outer covering of the fruit — has become very thick, and it’s that outer covering that deer eat. But if you open up the fruit, each seed is covered by this juicy, soft pulp, and it’s that that the monkeys and gibbons like.” She thinks that this might be a case where the tree evolved to appeal to multiple animal species to increase the chance of spreading viable seeds.

Despite the variety of animals eating the seeds, elephants are still the tree’s best chance of producing viable seedlings. When asked what might happen if elephants were to disappear from the region, Brodie responded, “That’s the million-dollar question.” (VOA)

Next Story

Sambhar Lake Becomes Death Bed for Large Number of Birds

The excessive salt in the water led to the poisoning, causing hypernectremia, which is water deprivation due to sodium intoxication

0
Sambhar Lake
After witnessing drought for many years, this year the Sambhar Lake, however, brimmed with water due to heavy rains. The inflow made the water toxic due to the change in its alkalinity. Pixabay

A deadly game of survival is on in the Sambhar lake of Rajasthan for decades — salt versus birds. The result came a few days back: thousands of birds were seen floating dead in the lake and their carcasses scattered on the edge of the 12 km catchment area.

The dead birds seen floating in this largest inland salt lake in the country, include plovers, common coot, black winged stilt, northern shovelers, ruddy shelduck, and pied avocet among many other migratory birds.

Harsh Vardhan, a renowned environmentalist, told IANS that no forest department official has ever been appointed to look after the lake. The lake comes under the Hindustan Salt Limited, a public limited enterprise formed in the post independence era to manufacture salt. Its job is to manufacture salt. So who should look after the lake; this has never been decided, he said.

The lake has not been handed to the forest department, and the area, where birds come, is no one’s land. Sambhar lake may be a part of the Hindustan Salt Ltd, but the company has nothing to do with the birds, he says.

The chief wildlife warden Arindam Tomar has maintained silence over the issue.

Even, Principal secretary, forest and environment Shreya Guha has washed her hands off the issue. All that she did was to a give statement that the Jaipur and Nagaur District Collectors have been asked to remove the bodies. She added that 4,800 birds have been dead till date, which is disputed by experts like Harsh Vardhan, who say that counting is not easy in the vast area.

Chief minister Ashok Gehlot on Thursday held a meeting on the issue.

Sambhar Lake
A deadly game of survival is on in the Sambhar Lake of Rajasthan for decades — salt versus birds. Pixabay

Meanwhile, Harsh Vardhan questioned the presence of several private salt miners and entrepreneurs, who have set shops in and around the lake. “They dig tube wells which suck water from the land making it parched. The remaining water gets evaporated leaving crystal of salts which are packed and sold in gunny bags,” he said.

Lack of water and drought has haunted Sambhar lake for years. State government has been spending huge money to woo tourists through activities like mobiking, balloning, race, Bollywood shoots, etc. A resort on the rim of the lake showcases salt manufacturing for the tourists. Crores of Rupees have been spent on the upkeep of the narrow gauge train and watch stations, but birds and conversation issues were always overlooked.

As Sambhar lake went dry, concentration of salt deposits came up within it. The water from surrounding rivers, meant to flow into the lake, was diverted by the miners.

After witnessing drought for many years, this year the lake, however, brimmed with water due to heavy rains. The inflow made the water toxic due to the change in its alkalinity.

The excessive salt in the water led to the poisoning, causing hypernectremia, which is water deprivation due to sodium intoxication, Vardhan said.

It seems birds which came in high numbers due to high water quantity this season died due to hypernectermia after consuming their feed which is the planktons, the microrganisms found in water.

Sambhar Lake
The dead birds seen floating in this largest inland salt lake i.e Sambhar Lake in the country, include plovers, common coot, black winged stilt, northern shovelers, ruddy shelduck, and pied avocet among many other migratory birds. Wikimedia Commons

The only step that has ever been taken by any government in the state was in 1981 when it was decided to designate the site as wetland and was renamed as the Ramsar site.

According to an estimate, around 60,000 birds visited the lake in a year which has come down to less than 20,000.

Vardhan says that if the lake remains with the Hindustan Salt Limited, which has been a loss making unit since years or if it is handed over to the private operators, who do excessive mining of water, then the lake and the birds are sure to die.

ALSO READ: Shah Rukh Khan Shares His Success Mantra

Experts like him want the lake to be handed over to the forest department which can develop it as a wetland. (IANS)