Large Herbivores Increase Forest Diversity

Rhinoceroses and elephants play a critical role in keeping the tropical forests of Southeast Asia healthy. These large herbivores help to disperse seeds and in doing so bolster forest regeneration and the maintenance of boidiversity.

The forests of Southeast Asia are rich in species number. They are also structurally dense which means dispersal of seeds can be tricky. The tightly packed forest dampens winds so wind dispersal is not often successful. Also, seeds that do make it to the ground often perish in the thick darkness shed by the dense canopy.

The most successful means of seed dispersal in such forests is to rely on seed transport by animals. Animals eat the fruit of the tropical vegetation and seeds are dispersed after the animal wanders away and either regurgitates the seeds or defecates them. Herbivores such as elephants and rhinoceroses not only eat more, they also wander further distances and can eat larger fruits and seeds. This means under normal conditions, these animals play a significant role in seed dispersal.

But habitat loss, poaching and killing of animals due to conflicts with humans, has taken a significant toll on the populations of rhinoceroses and elephants in Southeast Asia. Populations of Asian elephants, Javan rhinoceroses and Sumatran rhinoceroses have suffered dramatic declines and some species are on the brink of extinction. Such declines mean that the diversity and robustness of the very tropical forests in which elephants and rhinoceroses live are in grave danger.

Photo © Dicky Singh / iStockphoto.