Mark Shand - the brother of the Duchess of Cornwall - was the chairman of Elephant Family, which aims to save the endangered Asian elephant from extinction in the wild.
In a statement, the charity said it had "lost the head of our family".
The statement on the charity's website reads: "Today we have lost the head of our family. Mark Shand was a true force for conservation.
"He was both a legend and inspiration and above all our great friend. We ask at this time that people’s thoughts are with his loved ones. We will miss him always."
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There will be a few showers in the north, but otherwise dry for many with warm sunny spells before heavier rain in the south west.
David Davis is hoping to push Brexit withdrawal talks towards discussions on a future trading relationship between the UK and EU.
A fine start to Sunday but rain moves in from the southwest later on.