Scientists warn that many species are becoming extinct at a rapid rate
Nearly 200 countries have agreed on measures to protect the world's most threatened wildlife.
At a Bonn conference they pledged to set up a deep-sea nature reserve and increase by tens of millions of hectares the area of land protected.
The Convention on Biological Diversity meeting also agreed to prepare a firm position on the benefits and drawbacks of biofuels by the next forum in 2010.
But environmentalists said the outcome of the UN forum was unsatisfactory.
They said progress was too slow compared to the threat to the world's species.
Some 5,000 delegates from 191 countries attended the 12-day conference in the former German capital.
They agreed to set up the deep-sea nature preserve, expand reserve land to an area that - if combined - would be almost twice the size of Germany.
Other agreed steps included a ban on experiments to boost plankton growth to reverse climate change, because of the potential risks to other animals.
The delegates also pledged to set global standards for developing biofuels, a renewable energy that has been blamed for deforestation.
German Chancellor Angela Merkel said Berlin would commit 500 million euros (£392m) in funding for biodiversity work over the next for years, and another 500m euros each year after that.
German Environment Minister Sigmar Gabriel admitted later that he had not expected "real progress to be made on so many points".
But environmentalists said the progress achieved at the conference was still failing the UN Millennium Development Goal, which aims to "substantially reduce" biodiversity loss by 2010.
Scientists have warned that many species are becoming extinct at a rapid rate.