Why conserve biodiversity

The reasons fall into three groups: narrowly utilitarian, broadly utilitarian and ethical.

Narrowly utilitarian: nature gives direct economic benefits such as food (cereals, pulses, fruits), firewood, fibre and building material, industrial products (tannins, lubricants, dyes, resins, perfumes) and medicines.

More than 25 per cent of the drugs sold worldwide come from plants, and 25,000 plant species contribute to the traditional medicines of native peoples.

Bioprospecting means searching diversity at the molecular, genetic and species levels for economically important products; countries rich in biodiversity stand to gain enormously from it.

Broadly utilitarian: biodiversity drives ecosystem services. By one estimate, the photosynthesis of the Amazon forest supplies 20 per cent of all the oxygen in Earth's atmosphere.

Pollination, without which plants give no fruits or seeds, is a service provided by bees, bumblebees, birds and bats. There are also intangible benefits such as the pleasure of a walk in thick woods or a bulbul's song at dawn.

Ethical: every species has an intrinsic value, even with no present economic use. We have a moral duty to care for the species we share the planet with and to pass our biological legacy on in good order.