In terms of their role in the ecosystem, what do rhinoceros share in common with apex predators like lions and wolves?
Answer: Rhinoceros, like elephants, are one of our world’s few “megaherbivores” (defined as plant-eaters that weigh more than 2,000 pounds) and thus, as mature adults, are rarely subject to predation. Hence, rhinos’ impact on their ecosystem is disproportionately large. Like lions, wolves, and elephants, this earns rhinos the title of “keystone species.” Consequentially, their disappearance would likewise be catastrophic for their local ecosystems.
In the first and only study examining white rhinos’ role in shaping their ecosystem, researchers Joris P. G. M. Cromsigt and Mariska te Beest found that numerous species depend on the diversity of plant-life in the grasslands – a diversity which rhinos are instrumental in maintaining. Unlike elephants who are mainly browsers, eating from and pushing over trees, rhinos are grazers. Jason G. Goldman at University of Washington’s Conservation magazine writes, “Think of them like adorable [selective] lawn mowers with pointy spikes at the ends of their noses.”
Paleoecologist Jacquelyn Gill explains, “In many grassland and savannah systems, grazers increase biodiversity, by selectively eating certain kinds of plants over others. There is a lot of research that suggests that [grazers are] really important for maintaining diversity, as well as the coexistence of trees and grasses, by creating a shifting patch mosaic on the landscape.” In other words, rhinos selectively consume certain plant-life species, leaving room for other species that could otherwise not compete for space and this promotes a greater diversity of edible plants for other animals.
Many other megaherbivores, as casualties to human hunting and expansion, are already extinct. According to a paper by Gill, historically, the extinction of various megaherbivores in North America (e.g., mammoths, mastodons, horses, sloths, camels) resulted in large-scale ecosystem alterations to the diversity and populations of plant-life which, in turn, led to other species’ extinction. Hence, the disappearance of rhinoceros would result in a similar chain reaction that collapses an entire ecosystem.
- What Will Happen After All the Rhinos are Gone? (ConservationMagazine.org)
- Here’s What Might Happen to Local Ecosystems If All the Rhinos Disappear (Smithsonian.com)