Leaving the European Union could undermine the UK's efforts to tackle the illegal trade in wildlife products such as ivory, Environment Minister Rory Stewart has warned.
Brexit would jeopardise the UK's ability to influence international negotiations and drive ambitious policies to prevent the trade in rhino horn, illegal timber and other products which cost countries billions a year and are driving species towards extinction.
The Environment Minister said the UK was leading the way on issues such as maintaining the ivory trade ban and threatening to ban lion hunting trophy imports, and was influencing the rest of the EU to take action.
Mr Stewart said: "The United Kingdom is seen across the world as a leading force in the fight against wildlife crime and the illegal timber trade.
"Our calls for Europe to take action have been heard loud and clear - France, Germany, Sweden and others have banned the trade in elephant tusks, while UK-led talks to introduce measures to improve the sustainability of the hunting industry are closer to fruition.
"Europe has the influence to make a difference - showing the rest of the world that we can no longer stand for these cruel and exploitative practices.
"By working through the EU on environmental issues, the UK can influence 500 million consumers, and through them the global environment.
"This is vital for preserving our precious wildlife and natural resources for generations to come.
"The choice in this referendum is: economic security and global influence as part of the EU, or a leap in the dark. A vote to stay is a vote for certainty. I believe we will be stronger, safer and better off in Europe."
Mr Stewart made the comments ahead of a Government-organised event to discuss the significance of corruption as a driver of the illegal wildlife trade in advance of Prime Minister David Cameron's anti-corruption summit.