Sir David Attenborough has criticised cuts at the BBC's natural history unit in Bristol, warning it could lead to "very skimpy" programming.
Sir David's new series Life in Cold Blood focuses on amphibians
The unit is losing a third of its budget and 57 of 180 staff as the BBC adjusts to its licence fee settlement.
He told Radio Times: "You simply can't continue the same level of output, or if you do, you're going to replace it with something very skimpy."
Sir David's latest series, Life in Cold Blood, goes out on BBC One next month.
It is his final Life... series, ending a run which began in 1979 with Life on Earth.
The BBC has defended its plans. A spokesman said: "Major landmark pieces such as the forthcming Nature's Great Events, Frozen Planet, Life and events such as Springwatch will continue, and quality will in no way be compromised."