Abstract:
Due to international initiatives to increase the efficacy of conservation programs,
the critically endangered black rhinoceros is making a tenuous recovery from significant
population declines (Emslie & Brooks, 1999). However, as this species has slow
maturation and reproduction rates, maximizing the productivity and genetic health of
remaining populations is crucial to conserving this iconic animal. Assessing genetic
diversity of a threatened population using mitochondrial DNA (mtDNA), a maternally
inherited molecular marker, can elucidate the genetic viability of populations and
subsequently inform conservation strategies (Frankham, Ballou & Briscoe, 2010). Using
mtDNA this study assessed the genetic diversity of two subpopulations of the
southwestern arid subspecies of black rhinoceros, Diceros bicornis bicornis (D. b.
bicornis), at Addo Elephant National Park (AENP), South Africa. A total of 112
noninvasively collected fecal samples were assayed including 87 samples from the Nyathi subpopulation, 24 samples from the Addo subpopulation and one sample collected
outside of the park. Identities were assigned to the samples when possible. Only two
mtDNA D-loop haplotypes were identified. Low genetic diversity of this marker could
indicate that the population is at risk of inbreeding (Frankham, Ballou & Briscoe, 2010),
which could have serious implications for small populations like the D. b. bicornis at
AENP. This study also described a new set of primers that amplify the polymorphic
region between the two haplotypes identified at AENP, providing a new tool for
managers at the park to monitor the genetic variation within the subpopulations.
Although additional genetic testing is recommended to further characterize the genetic
diversity of these subpopulations of D. b. bicornis, the data reported in this study provide
critical information to the managers at AENP about the potentially limited genetic
variation in this important population.
