The black rhino is facing extinction, warns new research.
A major rethink is needed to save the species which has already been wiped out by hunters and poachers in many parts of Africa, say conservation experts.
Now it survives in only five countries: South Africa, Namibia, Kenya, Zimbabwe and Tanzania.
And renewed poaching threatens the remaining black rhino as rhinoceros horn has reached an “unprecedented and steadily rising” value.
An international team of researchers compared, for the first time, the genes of all living and extinct black rhino populations and found a “massive decline” in genetic diversity, with 44 of 64 genetic lineages no longer existing.
They say the new figures suggest that the future is “bleak” for the black rhino unless the conservation of genetically distinct populations is made a priority.
Professor Mike Bruford, of Cardiff University’s School of Biosciences, said: “Our findings reveal that hunting and habitat loss has reduced the evolutionary potential of the black rhinoceros dramatically over the last 200 years.
“The magnitude of this loss in genetic diversity really did surprise us – we did not expect it to be so profound.
“The decline in the species’ genetic diversity threatens to compromise its potential to adapt in the future as the climate and African landscape changes due to increased pressure from man.
“The new genetic data we have collected will allow us to identify populations of priority for conservation, giving us a better chance of preventing the species from total extinction.”
The research team used DNA extracted from a combination of tissue and faecal samples from wild animals, and skin from museum specimens.
They sequenced DNA from maternal mitochondrial genome and used classical DNA profiling to measure genetic diversity in past and present populations and compared the profiles and sequences of animals in different regions of Africa.
Now they plan to sequence the black rhino genome to see how the loss of genetic diversity is likely to affect populations across all of its genes.
Prof Bruford said that would provide “vital information” given the current poaching epidemic and the fact that some groups are being targeted more than others.