Asian elephants play a vital role in the ecology of the forest and help spread green cover because of their eating and movement pattern, says a study by the researchers of the Indian Institute of Science and Princeton University.
The researchers studied the eating and movement pattern of the domestic cattle, buffaloes and pachyderms as they are the ones who often venture inside the core of the forest and also travel a significant distance daily. More importantly, these species are herbivores.
They also chose the Buxa Tiger Reserve for their research. The core area of the reserve consists of native vegetation, surrounded by areas consisting of plantations and degraded forest tracts. According to a 2003 estimate, there are 217 elephants in Buxa.
In the study conducted by Nitin Sekar and Chia-Lo Lee from Princeton University and Prof Raman Sukumar from the IISc over three fruiting seasons (2010-2012), the researchers chose three species of plants for their study: Dillenia indica (the elephant apple), Artocarpus chaplasha (the chaplash) and Careya arborea (wild guava). These are mostly eaten by the cattle, buffaloes and elephants.
“It is well known that elephants can swallow very large seeds and excrete them undigested. Sometimes, seeds that pass through the elephant gut germinate better than those that are taken directly from the tree. Elephants are also able to disperse seeds far and wide due to the fact that they tend to cover several kms every day,” the research paper said.
In the fruit trees chosen by the researchers, they found that the elephant apple produces relatively hard fruit that are about 430 gm in weight. Because the hardness of the elephant-apple fruit, it makes pachyderms its predominant consumer. Chaplasha and wild guava trees produce softer fruits, which are easy for smaller fruit-eating species to handle.
The researchers conducted several feeding trials in order to observe how much of each species of fruit passed through each of the three animals’ (cattle, buffaloes and elephants) guts, as well as the time spent in the gut. Following this, they assessed the germination rate of seeds that had passed through each of the species’ guts.