The web of species and ecosystems composing planet Earth makes life possible, human and all other. Yet the scale of human activities has expanded so explosively in the twentieth century that we fray the workings of the very ecosystems on whose health we depend.

Many species have disappeared. Many times more are likely to become extinct within this decade. This widespread loss of species threatens to undermine the quality of life for all living things, including people.

The foundation supports work to maintain biodiversity in four globally important ecosystems (listed at left), as well as to advance US public understanding of the importance of healthy ecosystems for people's lives. These four ecosystems have been selected on the basis of their global importance for biodiversity, because they remain relatively intact with good prospects for maintaining their integrity, and because they offer opportunities to illustrate the links between ecosystems and human prosperity.