Restoration of a megaherbivore: landscape-level impacts of white rhinoceros in Kruger National Park, South Africa
Article first published online: 12 FEB 2014
© 2014 The Authors. Journal of Ecology © 2014 British Ecological Society
Journal of Ecology
Volume 102, Issue 3, pages 566–575, May 2014
How to Cite
Cromsigt, J. P. G. M., te Beest, M. (2014), Restoration of a megaherbivore: landscape-level impacts of white rhinoceros in Kruger National Park, South Africa. Journal of Ecology, 102: 566–575. doi: 10.1111/1365-2745.12218
- Issue published online: 17 APR 2014
- Article first published online: 12 FEB 2014
- Accepted manuscript online: 22 JAN 2014 08:44AM EST
- Manuscript Accepted: 16 JAN 2014
- Manuscript Received: 25 SEP 2013
- Marie Curie Intra-European. Grant Number: PIEF-GA-2008-220947
- Marie Curie Career Integration. Grant Number: PCIG10-GA-2011-304128
- Swedish thematic research programme Wildlife & Forestry
- Stellenbosch University
- Ceratotherium simum ;
- consumer-resource feedbacks;
- grazing lawn;
- megafaunal extinctions;
- plant–herbivore interactions;
- rhino poaching;
- role of apex consumers in ecosystem functioning;
- top-down ecosystem control
Megaherbivores have been lost from most ecosystems world-wide, and current increases in poaching of rhino and elephant spp. threaten their status in the systems where they still occur. Although megaherbivores are said to be key drivers of ecosystem structure and functioning, empirical evidence is strongly biased to studies on African elephant. We urgently need a better understanding of the impact of other megaherbivore species to predict the consequences of megaherbivore loss.
We used a unique ‘recolonization experiment’ to test how a megagrazer, white rhinoceros, is affecting the structure of savanna grasslands in Kruger National Park (KNP).
With a 30-year record of rhinoceros distribution, we quantified how they recolonized KNP following their re-introduction. This allowed us to identify landscapes with high rhino densities and long time since recolonization versus landscapes with low rhino densities that were recolonized more recently but were otherwise biophysically similar. We recorded grassland heterogeneity on 40 transects covering a total of 30 km distributed across both landscapes. We used two proxies of grassland heterogeneity: % short grass cover and number of grazing lawn patches. Grazing lawns are patches with specific communities of prostrate-growing stoloniferous short grass species.
Short grass cover was clearly higher in the high rhino impact (17.5%) than low rhino impact landscape (10.7%). Moreover, we encountered ~20 times more grazing lawns in the high rhino impact landscape. The effect of rhino on number of lawns and on short grass cover was similar to the two dominant geologies in KNP, basalt-derived versus granite-derived soils.
Synthesis. We provide empirical evidence that white rhinoceros may have started to change the structure and composition of KNP's savanna grasslands. It remains to be tested if these changes lead to other ecological cascading effects. However, our results highlight that the current rhino poaching crisis may not only affect the species, but also threaten the potential key role of this megaherbivore as a driver of savanna functioning.