The Duke of Cambridge has helped honour conservationists working in Africa to combat the illegal wildlife trade at a charity function, saying he was "in awe" of their achievements.
The dinner and presentation was hosted by Tusk, which has a 25-year history of supporting conservation projects throughout the continent.
A lifetime achievement award was handed to Garth Owen-Smith for his successful community-driven initiatives in Namibia, while the inaugural Wildlife Ranger award went to Kenyan Edward Ndiritu for exhibiting bravery and leadership amid the life-threatening dangers posed by poachers.
The Tusk Conservation Award - which recognises an "up and coming" conservationist - was given to Dr Emmanuel de Merode, who works to protect the biodiversity of Virunga National Park.
William praised the courage, commitment and humble nature of the trio and said each man had faced adversity in carrying out his work.
He said: "Without people like Garth, Emmanuel and Edward - the true unsung heroes of conservation in Africa - we would be facing a very dire situation indeed."
Dr de Merode, he pointed out, was nearly killed in an ambush two years ago. Eleven of his colleagues were also killed by militia in August.
William told the guests one of the reasons he was passionate about conservation was due to the human impact it involved.
He said: "As the world's population becomes more and more urbanised, an increasing number of people will grow up with little or no connection to the natural world."
William added: "This will become a major challenge for conservationists. If people cannot see it, they will never learn to value it, or worse still will take little interest in looking after it."
The Duke said most rangers - many of whom were "out-resourced and out-gunned" - never would have imagined having to put their lives on the line to protect their country's heritage.
He expressed concern about the children left behind when rangers were killed.
"As I have said in the past, it is these children's future that is blighted so tragically by the illegal wildlife trade and it is their birthright to their natural resources that is stolen," he told the function.
"This is the sharp end of the human impact of one of the world's most pressing conservation crises."
But William said the winners' achievements highlighted how much there was to be positive about in the ongoing battle.
He said: "I share an optimism with all of you that we can win this battle. And we will win this battle by working together and by having a collaborative approach across the whole spectrum."
Accepting his award, Mr Owen-Smith paid tribute to the communities in which he worked.
He said: "If we were anything, we were the catalysts. The work was done - it was done by the communities themselves."
He added: "They are the heroes. They have changed conservation."
Earlier in the evening Dr de Merode said the awards, and the Duke's involvement in them, helped drive global attention.
He said: "It's not just because we need support, we need a lot of attention on those issues."
It was a little-known fact that the ongoing conflict in eastern Congo had cost the lives of six million people, Dr de Merode said.
"The park is not just about wildlife, it's about bringing stability to the whole region," he said.
What made the park so vital was its rich diversity, he said. It is the only park in the world that is home to three types of great apes.
He said: "It goes from 17,000 feet to 3,000 feet - it has this incredible range of landscapes."
He added: "It's somewhere that can't really be abandoned in terms of its contribution to world heritage."
Tusk founder Charlie Mayhew set up the charity at the height of the last great poaching crisis for the ivory trade.
He said: "Ironically, we seem to have come full circle again."