According to the red list of the International Union for Conservation of Nature (IUCN), elephants are in 'danger of extinction' and the two rhinoceros species are 'critically endangered'.
Asian tapirs are no elephants
In light of the situation, the research team evaluated the seed-dispersing capacity of another large herbivore weighing 300 kg. For cultural reasons it is not hunted and has a similar digestive system to that of elephants and rhinoceroses: the Asian tapir (Tapirus indicus).
The study allowed researchers to analyse the effect of dispersion by tapirs on the seed survival of nine different plants. This included some large plant species such as the mango tree and durian, as well as other smaller species like the 'elephant apple' (Dillenia indica).
Among other outcomes, the results show that tapirs defecated 8% of the tamarind seeds ingested (none of which germinated) compared to elephants, who defecated 75% of the 2,390 ingested seeds (65% of which germinated).
"The Asian tapirs spit, chew or digest the majority of large seeds. This either destroys them or leaves them in the same place. As a result, they are not good dispersers for plants with large fruits and seeds," confirms Campos-Arceiz. In this sense, "given the role that they play they belong to a different group to elephants and rhinoceroses."
Stopping illegal hunting is the priority
"If these megaherbivores disappear from the ecosystem, their contribution to ecological processes will too be lost and the path of the ecosystem will change irreversibly," explains the lead author, who goes on to state that "the most probable consequences are the change in the structure of the undergrowth and the forest and the loss of certain species." Elephants and rhinoceroses play a unique ecological role that cannot be replaced by other species.
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FECYT - Spanish Foundation for Science and Technology