Today the Swedish University of Agricultural Sciences released a press release on a paper published in Journal of Ecology, “Restoration of a megaherbivore: landscape-level impacts of white rhinoceros in Kruger National Park, South Africa” by Cromsigt & te Beest.

The press release can be accessed via this link and the authors have kindly composed a brief summary of their paper below. 

Landscape-level impacts of a reintroduced megagrazer

Megaherbivores (animals weighing ≥ 1,000 kgs) are hypothesized to be key drivers of ecosystem functioning and structure because they are not top-down controlled by predation. However, empirical studies on the ecosystem impact of megaherbivores are strongly biased to one species, the African elephant. There is very little contemporary evidence for ecosystem-scale impacts by other megaherbivore species. We quantified how rhino recolonised Kruger National Park (KNP) following their re-introduction in the 1960s to create a unique ‘recolonization experiment’ and test how this megagrazer is affecting the structure of savannah grasslands. We identified landscapes that rhino recolonised long time ago versus landscapes that were recolonised more recently. We assumed that time since colonization represents a proxy for extent of rhino impact. We recorded grassland heterogeneity on 40 transects covering a total of 30 km. Short grass cover was clearly higher in the high rhino impact than low rhino impact landscape. Moreover, we encountered ~ 20 times more grazing lawns, a specific grassland community, in the high rhino impact landscape. Concluding, white rhinoceros may have started to change the structure and composition of KNP’s savannah grasslands. However, current poaching rates, > 1,000 white rhino per year, will drive rhino to extinction with the next 20 years. Our results highlight that this poaching crisis not only affects the species but threatens the potentially key role of this megaherbivore as a driver of savannah functioning.

Joris Cromsigt
Swedish University of Agricultural Sciences