Sir

The authors of the Commentary “Diversity without representation” (Nature 442, 245–246; 2006) highlight the world's ineffectual response to the crisis of biodiversity loss. I agree that an international body similar to the Intergovernmental Panel on Climate Change would be useful. But I believe that what is most important is for individuals, corporations and governments to take responsibility for the impact of their activities on biodiversity, using the 'avoid, mitigate and compensate' hierarchy from the Convention on Biological Diversity's voluntary guidelines for impact assessment, to ensure that their actions do not result in net biodiversity loss.

The main obstacle to such action has been the lack of standards to measure impacts and to identify appropriate compensation. Recently, however, considerable progress has been made on biodiversity offsets, a process by which impacts are measured, then conservation investments made to ensure that the net impacts to biodiversity are neutral or even positive.

The most advanced analytical work involves wetlands in the United States, where any impact must be offset by restored wetlands that are equivalent in function to that lost. But leading companies are taking steps to offset their impacts in other ecosystems. For example, Peru's forests of Polylepis — home to several endangered bird species — have been reduced in size by 97% since the time of the Incas, especially in recent decades by grazing and fuelwood collecting. Now the company Minera Antamina has undertaken to protect and reforest an area hundreds of times larger than the area of Polylepis affected by its mine (see http://biodiversityneutral.org).

Although regulations requiring offsets are essential to halt the loss of habitat, existing frameworks are sufficient for individuals and corporations to take voluntary responsibility for the loss of biodiversity caused by their activities. And should an intergovernmental panel on biodiversity be established, offsets would provide an immediate focus for research and policy-making.