A northern white rhino is retiring from an international breeding program — and it’s not good news for her species.

Najin, 32, is one of the world’s last two northern white rhinos. She lives under guard in a Kenya nature preserve with her daughter Fatu, who is now the only one left in a desperate global effort to save the species from extinction.

“Weighing up risks and opportunities for the individuals and the entire species rendered this decision without an alternative,” BioRescue, the international consortium of scientists and conservationists leading the effort, said in a statement Thursday.

There are no known male northern white rhinos alive, after the world’s last one — an ailing, elderly rhino named Sudan — died in 2018. BioRescue has since collected eggs from Najin and Fatu as part of a project that aims to implant artificially developed embryos into a different subspecies to produce offspring.

After the eggs were extracted, they were airlifted to an Italian lab to be fertilized using sperm from deceased males. Neither of the female white rhinos is able to carry a calf to term, so the project aims to use southern white rhinos as surrogate mothers for the embryos.

The project is a moonshot for the technically extinct species, which in its heyday used to roam parts of central and eastern Africa. Poaching decimated the species in recent decades.

Najin was born in a safari park in the Czech Republic in 1989 and moved to Ol Pejeta Conservancy in Kenya in 2009 for a natural breeding program. Five years later, scientists decided an assisted reproduction program offered the only hope for the species’ survival.

Extinction of the northern white rhino — an example of what is known as a “keystone species” — could have major ripple effects, said Barbara de Mori, an ethics professor at Padua University in Italy and BioRescue’s chief ethicist. The rhino is “crucial for the equilibrium of the ecosystem to which the species belongs,” she said.

Researchers have only been able to harvest a few eggs from Najin and none could be fertilized successfully. De Mori called the decision to retire Najin “difficult” but necessary to preserve the aging rhino’s welfare.

The team has successfully created 12 northern white rhino embryos using Fatu, the younger rhino, however — leaving hope that the project could succeed. The researchers are racing to produce calves as fast as possible so that Najin can raise them and “transfer the social competencies of this species,” de Mori said.

Apart from ensuring that the ecosystem does not lose a critical species, de Mori said the fight to preserve the northern white rhino symbolizes the importance of people taking responsibility for human destruction of the environment.

“The northern white rhino is a symbol for us to understand how important it is to value the consequences of our actions on the planet,” she said. “To try to save this species from the brink of extinction is to try to give the new generations, to give young people the chance to still have this species on Earth.”