A tramper killed in Arthur's Pass National Park on Saturday was a world-renowned botanist.
Dr Peter Wardle, 76, of Christchurch, died while trying to cross the Waimakariri River near Klondyke Corner with eight other trampers from Christchurch's Over Forties Tramping Club, including his wife.
Snow melt was being blamed for the rising river levels in Arthur's Pass National Park, which claimed Dr Wardle's life.
"He was attempting to cross the river with two other members of his party when he appeared to have stumbled and fallen into the water," Inspector Alan Weston said yesterday.
He was then swept downstream for some distance before being pulled from the water by members of his party.
Liz Griffiths, who helped pull Dr Wardle's body from the river to the shore, told the Press newspaper she was certain he died of a heart attack or other natural cause rather than drowning.
"All of us thought he did not drown because he did not move (after entering the water)," she said.
Police said a post mortem would be performed to determine the cause of his death.
Ms Griffiths said Dr Wardle and his wife, Margaret, slipped and were swept away by the swiftly moving river as they tried crossing knee-deep water near Klondyke Corner.
Mrs Wardle, who was not injured in the fall, was being comforted by their children Penny and Rob, Dr Wardle's brother, John, said yesterday.
Warwick Harris, former director of the erstwhile Department of Scientific and Industrial Research's botany department, said Dr Wardle's death was a tremendous shock.
Landcare Research ecologist Colin Meurk described Dr Wardle as a towering force in New Zealand ecology.
"Everyone of my generation regarded him as the oracle on particularly plant ecological matters."
In 1990 he was awarded the Royal Society of New Zealand's top honour, the Hector Medal.
