Abstract:
Shifting prey selection has been identified as a mechanism potentially regulating
predator–prey interactions, but it may also lead to different outcomes, especially in more
complex systems with multiple prey species available. We assessed changing prey selection by
lions, the major predator for 12 large herbivore species in South Africa’s Kruger National
Park. The database was provided by records of found carcasses ascribed to kills by lions
assembled over 70 years, coupled with counts of changing prey abundance extending over 30
years. Wildebeest and zebra constituted the most favored prey species during the early portion
of the study period, while selection for buffalo rose in the south of the park after a severe
drought increased their vulnerability. Rainfall had a negative influence on the proportional
representation of buffalo in lion kills, but wildebeest and zebra appeared less susceptible to
being killed under conditions of low rainfall. Selection by lions for alternative prey species,
including giraffe, kudu, waterbuck, and warthog, was influenced by the changing relative
abundance and vulnerability of the three principal prey species. Simultaneous declines in the
abundance of rarer antelope species were associated with a sharp increase in selection for these
species at a time when all three principal prey species were less available. Hence shifting prey
selection by lions affected the dynamics of herbivore populations in different ways: promoting
contrasting responses by principal prey species to rainfall variation, while apparently being the
main cause of sharp declines by alternative prey species under certain conditions. Accordingly,
adaptive responses by predators, to both the changing relative abundance of the principal prey
species, and other conditions affecting the relative vulnerability of various species, should be
taken into account to understand the interactive dynamics of multispecies predator–prey webs.
