Tea picked by hand on the plantations of Pary Agro in Tamil Nadu, southern India. © IRD/P. Lavelle
 
 
 
 
Pontoscolex corethrulus Mull, in India. © IRD/P. Lavelle

Knowledge of the multiplicity of living creatures enables us to garden in harmony with nature all over the globe. A plant sends its roots into the earth, and is swayed by the wind. Turning the soil with a spade brings out worms, centipedes, spiders, larvae, and a mass of invisible micro-organisms, fungi and bacteria.

These creatures scurry about in the earth looking for food. They degrade organic matter into a form that can be assimilated by the roots of plants. Earth worms also help aerate the soil by digging tunnels. Moles help the gardener by eating harmful larvae.

Humans have also made fire their ally. They use it in several parts of the world to clear land for cultivation. South African gardeners know the role it has played in the ecology of fynbos (maquis) in the Cape Floral Kingdom, where heat and smoke are used to germinate the seeds of a number of rare ornamental plants.

The flora of tropical forests, like the ocean depths, is the final "terra Incognita" of naturalists.

Bathyscaphes (deep-sea research vessels) and radeaux des cimes (dirigibles for observing the tree canopy) will continue to move through the ocean depths and the sky for a long time before they can identify all of the hundreds of unknown animal and plant species.