The "great innovator" behind Marwell Zoo has died after a short illness.
John Knowles opened up the attraction near Winchester, Hampshire, in 1972, specifically to breed endangered animal species.
He purchased Marwell Hall and the surrounding 417 acres of land, spending more than £1m to realise his dream.
James Cretney, chief executive of Marwell Wildlife, described him as a "great innovator" with a "pioneering approach".
He said Mr Knowles' work "did much to change the outlook and perception of the sector".
He added: "He implemented many changes to the operations of zoos and conservation, and we have a lot to thank him for.
"Our deepest sympathies go out to Mr Knowles' family."
Speaking in 2009 about setting up the zoo, Mr Knowles told the BBC: "I was convinced then, and I still am today, that many animals have no future.
"Therefore it was vital to create a zoo that would keep species going."
He tackled difficulties such as planning permission and the transportation of animals to open up the attraction within three years.
Early residents at the zoo included Przewalski's horses, scimitar-horned oryx, and Grevy's zebra.
Mr Knowles set up mixed paddocks of large groups of animals grazing together, after being told it was "impossible", a Marwell Wildlife spokeswoman said.
He also contributed to the establishment of co-operative breeding programmes in Europe.
He was awarded an OBE for his services to conservation in 1991, and founded the Marwell Zimbabwe Trust (now Dambari Wildlife) in 1997.
He retired in 2006.