How Have Plants In The Great Karoo Of South Africa Adapted To Survive On Low Rainfall Levels?

The root systems of plants in the Great Karoo have evolved in a manner of ways in order to take maximum advantage of whatever moisture is present in the soil.

Grasses, for instance, have shallow root systems which are able to extract water for its survival from even the lightest of rain showers. Root sheaths prevent drying out of the roots during hot, dry periods.

Annual shrubs, on the other hand, have deep growing tap-roots with evenly distributed lateral roots. Most evergreen shrubs also have long tap-roots that branch deep down in the soil. Deciduous shrubs take a different path and branch their tap-roots just below the surface and send up to eight lateral roots in all directions.

Succulents, by contrast, have shallow roots systems which may spread up to 2.5 metres just below the ground surface in order to capture as much as possible from even small amounts of rainfall.

The various root systems enable plants to survive low and often irregular rainfall and to grow spasmodically, being stimulated by rainfall and retarded by cold and drought.

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