NEW YORK — Anna Merz went to Kenya seeking a serene retirement. Instead, she became so appalled by the slaughter of black rhinoceroses that she helped start a reserve to protect them, becoming a global leader in the fight against their extinction. Ms. Merz, the founder of the Lewa Wildlife Conservancy, died April 4 in Melkrivier, South Africa. She was 81.
She left no immediate survivors, but more than 70 black rhinos, including one born the day she died, continue to thrive in the sanctuary away from poachers who kill the animals for their horns.
As a young woman, Ms. Merz roamed the world and ended up in Ghana, where she married twice, ran an engineering firm, and became active in wildlife conservation. In Kenya, her revulsion at seeing the carcasses of rhinos strewn about a national park, each missing its distinctive double horn, compelled her to change her retirement plans.
She started looking for land to use as a rhino reserve and, after many rejections, found a patron, David Craig, who owned a vast tract near Mount Kenya. They agreed to set aside 5,000 acres for the project, which opened in 1981. It has since grown to 61,000 acres.
Lewa’s success helped the black rhino population double to 4,880 over the last decade, still a far cry from the millions that once roamed Africa. Lewa is home to 10 percent of Kenya’s black rhinos, and its efforts have bolstered the dream of returning the species to its former dominance in northern Kenya.
Lewa rhinos must be regularly resettled elsewhere because the success of the breeding program — the reserve’s numbers grow 10 percent a year — has caused overcrowding and fights.
Ms. Merz’s example has inspired other wildlife conservation efforts and has helped make the black rhino, which is still critically endangered, a global symbol of extinction prevention.
‘‘I have met many remarkable animal specialists during my life, but none as extraordinary as Anna Merz,’’ Desmond Morris, the zoologist and author, wrote in the foreword to her 1991 book, ‘‘Rhino at the Brink of Extinction.’’ “What Joy Adamson was to lions, Dian Fossey was to gorillas, and Jane Goodall is to chimpanzees, Anna Merz is to rhinos.’’
Florence Ann Hepburn was born in Radlett, England, and moved between London and Cornwall as a child. A formative experience was seeing a museum exhibit on the dodo, which is believed to have become extinct in the 17th century. Another was being on a beach at age 9 when a German fighter plane attacked: A stranger threw his body on top of hers and died saving her life.
She graduated from Nottingham University, studied law and traveled to exotic places before settling in Ghana. There she married Ernest Kuhn, whom she divorced in 1969, and Karl Merz, who died in 1988. In Ghana she trained racehorses, rescued chimpanzees, and was named an honorary game warden by the nation’s game department.
The Merzes moved to Kenya in 1976. After securing the first 5,000 acres for the reserve, Ms. Merz, using her inheritance, built an 8-foot-high fence, then began rounding up rhinos using helicopters and stun guns. She hired more than 100 armed guards, bought a plane for surveillance and built a network of spies to inform on poachers.
Those who kill the rhinos sell the horns largely to Asians, who grind them for folk medicine, and Arabs, who carve them to use as dagger handles. Prices for rhino horns can run higher than those for gold.
“These are very ruthless people,’’ she said of poachers.
Ms. Merz herself carried a gun and knife.
At first she used her own money to finance the project, a total of more than $1.5 million, but she came to rely on donations. The American Association of Zoo Keepers helped by raising millions for rhino preservation through its annual ‘‘Bowling for Rhinos’’ campaign. Winners spent a week with Ms. Merz at her reserve.
Giving local people a stake in the reserve was crucial to its success. She employed them, built schools and medical clinics for them, and helped foster the tourist industry. Besides rhinos, of both the black and white species, visitors come to see lions, elephants, and other animals. Prince William of Britain and Kate Middleton became engaged in 2010 while staying at a cottage there.