By Tim Hirsch
BBC News environment correspondent
Brazilian President Luis Inacio Lula da Silva has criticised richer countries for not providing enough money to help preserve the variety of life on Earth.
More than 800 animal and plant species face extinction
President Lula made his comments while opening the ministerial meeting of the UN Convention on Biological Diversity.
He told delegates in Curitiba it was unacceptable the world's poorest nations were suffering the main burden.
Earlier, ministers were warned time was running out in the battle to slow the loss of plant and animal species.
With the world's most diverse ecosystems located in developing countries, the international effort to slow the rate of their decline has become mired in North-South political arguments.
President Lula said it was unacceptable that the poorest countries in the world should be bearing the main brunt of environmental degradation caused by unsustainable consumption of resources by the richer world.
He went on to say it was worrying that at the very moment in which conservation efforts were growing around the world, the financial resources to support them were being reduced.
That was a reference to an argument at this conference over contributions from the United States and other industrialised countries to a UN fund directed at environmental protection.
Earlier, the official in charge of the biodiversity convention, Ahmed Djoghlaf, warned that time was running out for governments to meet their commitment to slow the loss of species variety by 2010.
If the world carried on with business as usual, he said, that target would be missed.