1. The variety of species (species diversity) or other taxa of animals, micro-organisms and plants in a natural community or habitat, or of communities in a particular environment (ecological diversity), or of genetic variation in a species (genetic diversity, q.v.). The maintenance of a high level of biodiversity is important for the stability of ecosystems.

2. The variety of life in all its forms, levels and combinations, encompassing genetic diversity, species diversity and ecosystem diversity.