BACKGROUND: African wildlife experienced a reduction in population size and geographical distribution over the last
millennium, particularly since the 19th century as a result of human demographic expansion, wildlife overexploitation,
habitat degradation and cattle-borne diseases. In many areas, ungulate populations are now largely confined within a
network of loosely connected protected areas. These metapopulations face gene flow restriction and run the risk of
genetic diversity erosion. In this context, we assessed the “genetic health” of free ranging southern African Cape
buffalo populations (S.c. caffer) and investigated the origins of their current genetic structure. The analyses
were based on 264 samples from 6 southern African countries that were genotyped for 14 autosomal and 3
RESULTS: The analyses differentiated three significant genetic clusters, hereafter referred to as Northern (N), Central
(C) and Southern (S) clusters. The results suggest that splitting of the N and C clusters occurred around 6000 to
8400 years ago. Both N and C clusters displayed high genetic diversity (mean allelic richness (Ar) of 7.217, average
genetic diversity over loci of 0.594, mean private alleles (Pa) of 11), low differentiation, and an absence of an
inbreeding depression signal (mean FIS = 0.037). The third (S) cluster, a tiny population enclosed within a small
isolated protected area, likely originated from a more recent isolation and experienced genetic drift (FIS = 0.062,
mean Ar = 6.160, Pa = 2). This study also highlighted the impact of translocations between clusters on the genetic
structure of several African buffalo populations. Lower differentiation estimates were observed between C and N
sampling localities that experienced translocation over the last century.
CONCLUSIONS: We showed that the current genetic structure of southern African Cape buffalo populations results
from both ancient and recent processes. The splitting time of N and C clusters suggests that the current pattern
results from human-induced factors and/or from the aridification process that occurred during the Holocene period.
The more recent S cluster genetic drift probably results of processes that occurred over the last centuries (habitat
fragmentation, diseases). Management practices of African buffalo populations should consider the
micro-evolutionary changes highlighted in the present study.
We are especially thankful to all the institutions that participated in the
sample collection: UP-MRI and State Vets (D. Cooper, Hluhluwe-iMfolozi Park),
Centre de Coopération Internationale en Recherche Agronomique pour le
Développement (CIRAD) partners based in Botswana, CIRAD and RP-PCP
partners based in Zimbabwe, and the Fondation Internationale pour la
Gestion de la Faune (IGF, France). We would also like to thank S. Le Bel, C.
Foggin, R. Bengis, M. Hofmeyr, N. Owen-Smith and A. Marchal for providing
supplementary specific information about buffalo demographic parameters.
Furthermore, we would like to thank Pim Van Hooft (University of Wageningen,
The Netherlands) for his deep knowledge and support in reconstructing
the male haplogroup network.