2. ABOUT WHITE RHINO
• “The white rhinoceros or square-lipped rhinoceros is the largest extant species of
rhinoceros. It has a wide mouth used for grazing and is the most social of all rhino
species.” Wikipedia
• As of 2015 only 4 Northern White Rhinos left in the world
• Armed guards for protection in Kenya
3. INTRO
• Megaherbivores lost from ecosystems worldwide
• Poaching/ hunting
• Recolonization experiment conducted testing effects of white rhinoceros (mega-
grazer) in Kruger National Park (South Africa)
• Went extinct in KNP in 1896
• Shown to have an impact on short grass cover and grazing lawns
• Apex consumer (top/ alpha predator) = keystone species
4. MEGAHERBIVORE IMPACTS
• Populations mostly limited by food availability (vegetation limits population size)
• “. As a result, the Pleistocene extinctions of megaherbivores have been argued to
drive major historic ecosystem change, including changing fire regimes, plant
communities (Gill et al. 2009) and cascading extinctions of other taxa (Owen-Smith
1987).”
• White Rhino has a great impact in fenced area, high in numbers (fence effect). Do
they still have this same impact under more natural conditions?
• Used reintroduction to non colonized areas to test
5. KRUGER NATIONAL PARK
• “Kruger National Park is situated in the north-eastern corner of South Africa
bordering Mozambique in the east and Zimbabwe in the north”
• Climate strongly seasonal and subtropical
• “more open, productive, grasslands on the basalts and denser bushland savanna on the
granites”
• One of Africa’s largest reserves; houses lions, elephants, rhinos, leopards, and buffalos
6. MATERIALS AND METHODS
• Total of 336 successfully released (330 in south, only 6 in north)
• Used aerial census counts to map rhino recolonization patterns and density
• Fixed-wing count
• Counts all diverse species
• Helicopter count
• Counts megaherbivore species (done annually)
*rhino recolonization map created
• Spatial analyst tool to estimate kernel density that reflects aggregated observation
density
• Due to poaching, this info isn’t able to be published fully
7. COLONIZATION BY AREA
• 3 areas split by two main rivers forming strong barriers
• Area A had already been colonized by white rhino in 1988
• Area B had only 30% of area colonized in 1988
• Area C had only 10% area colonized in 1988
• In 2010…
• Area A whole area totally colonized (most dense)
• Area B 86% area colonized
• Area C 40% of area colonized (least dense)
8. EXPERIMENTAL DESIGN
• Studied areas A and B excluding C due to differences in ecosystem
• Climate, soil and vegetation
• Area A longer history with more density = high rhino impact
• Area B colonized more recently with much less density
• Grassland Heterogeneity Determination
• Used GIS (the visual representation of a geographic dataset in any digital map
environment. )
• Distributed transects to according to random sampling scheme to control for factors
such as rainfall, fire frequency, and tree cover
• Quantified grassland characteristics during Jan and Feb wet seasons and took into
account grass height, dung pellets, grazing lawn state, percent covered by short grass,
etc.
9. DATA ANALYSIS/ RESULTS
• Used factorial data analysis
• Good for describing variability among observed correlated variables
• Used due to the high vs low factors being observed in this study
• Results: not dependent on geology
• 20.9 times less likely to find grazing lawns in the low rhino impact than the high rhino
impact landscape
• 1.8 times less likely to find short grass patches in low rhino impact than high
• White Rhino observed 7.4 times more often in high rhino impact areas than low impact
areas
• Other megaherbivores densities including elephants were unrelated to rhino impact
10. RESULTS CONTINUED:
• Dung pellets were also counted for other herbivore species including elephants,
impala, buffalo, warthogs, black rhinos, etc…
• Did not find significant correlation between dung count and kernel density, so dung
count was excluded in testing for treatment effects of other grazers, rather focused on
density estimates
11. BASALT VS. GRANITE
• White rhino observed 1.8 times more often on granites than on basalts
• Wildebeests found 66.7 times greater on basalts than granites
• Zebra found 3.7 times greater on basalts than granite, in low rhino impact areas
• Buffalo densities 10 times greater on basalts than granite, densities 5.5 times greater in low
vs high rhino impact areas (may be avoidance)
• Impala densities unrelated to geology, but found 2.5 times greater in high rhino impact
areas
• Warthogs- on basalts were 2.2 times greater in high rhino impact areas; on granites- were
slightly greater in low rhino impact areas
• (Basalt= fine grained volcanic rock // granite = hard granular, crystalline rock)
12. DISCUSSION
• Results suggest that this mega-grazer is increasing grassland heterogeneity
• In this experiment with little manipulation, transects were placed so areas didn’t
differ in average rainfall and fire frequency
• Because other large mega-herbivores like elephants behave differently (eat, live),
they did not confound results
• Smaller species such as impala and warthogs increase grazing lawns and short grass,
however small body mass does not allow them to intensively crop wall grass like
white rhino
• Study showed grass height dropped 10cm when excluding white rhino, and not at all
when excluding any other smaller-bodied grazers
• White rhino may have facilitative effect on impala and warthog densities, densities
higher in areas of high rhino impact
13. DISCUSSION: CRESTS VS CATINAS
• Transport of nutrients down the slope of a catena(soul type)creates intensively
grazed nutrient hot spots along its foot slopes and relatively nutrient-poor taller
grasslands on the crests
• Focused on crests to avoid confounding results
• Results suggest white rhino may be a biotic driver of grassland heterogeneity
• Suspect termites may also play a role
• Impact of rhino may have cascading affects, creating habitat for other species and
influencing tree dynamics, though their current effects are small in KNP
14. NORTHERN WHITE RHINO LEGACY
• https://www.youtube.com/watch?v=r_Fd9es_B6Y
• Now…
• “The death of Nola, a 41-year-old female who had to be euthanized at San Diego
Zoo following a routine operation to treat an abscess, leaves just three individuals
remaining in the world. Two are infertile females, the solitary male has low fertility;
all are elderly.”
