By Roelof Bezuidenhout
Before the advent of cellphone apps that can instantly identify almost any plant, students had to learn about plants the old-fashioned way: through practical classes and by memorising tongue-twisting scientific names.
South Africa is one of the most biodiverse countries in the world, with a vast and varied floral kingdom. Fortunately, farmers don’t need to know every species. To manage their veld productively, livestock farmers only need to recognise 50 or so key plants, including grasses, shrubs, trees and annuals.
Why? Because competent veld managers would understand which species provide the best grazing in their particular region, and would recognise less palatable types and invasive plants. Farmers need to assess whether the grazing on their land is improving, deteriorating or staying the same in terms of plant composition. Some plants offer excellent grazing value, others are little more than ground cover. And the better the grazing, the better the livestock condition.
Three stages of plant succession
An abandoned cropland or an overgrazed camp will, if left undisturbed, eventually recover and return to a natural cover of grasses and shrubs similar to the surrounding veld. But before that happens, the land must go through the three stages of plant succession: pioneer, subclimax and climax. With each stage, environmental stability increases. If veld regresses to the pioneer stage, it takes targeted intervention to help it progress again. Knowing which stage your farm, camps or even sections of camps are in can guide your grazing and land-use strategies.
Different plant species are typical of each succession stage and can act as indicators of veld condition. For example, in the summer rainfall region:
• Aristida adscensionis (annual three-awn, or eenjarige steekgras) is a pioneer grass;
• Eragrostis superba (saw-tooth love grass) is a subclimax species; and
• Themeda triandra (red grass, or rooigras) is a classic climax grass.
In the Karoo, dwarf shrubs represent the various stages. Each region has its own natural plant communities, depending on climate and soil type. Sometimes, plants from all three stages may coexist, especially in the subclimax stage.
The pioneer stage typically appears on bare or disturbed soils, where grazing capacity is low. Pioneer plants – usually fast-growing annuals – help stabilise and rebuild the soil. As the vegetation cover improves, these pioneers give way to species that are better adapted to the improved conditions. Grazing quality improves accordingly.
The climax stage has the highest environmental value, but it’s not always ideal for farming. For example, indigenous forests or a dense spekboom thickets offer little grazing value for cattle or sheep.
Recognising the plant succession stage of your veld is key to knowing its condition – and what it can sustainably support.
Indicator species
Two other categories of vegetation apply here, namely indicator species known as increasers and decreasers. They reflect the direction in which the veld is changing. Progressive succession leads to veld improvement, whereas retrogressive succession indicates veld deterioration, often a result of overgrazing.
Decreasers are the more palatable plants that are readily grazed or browsed; they tend to decline under poor management. Increasers are the less desirable plants; they typically increase under poor management. Invaders are plants that do not naturally occur in the area; they can spread aggressively and should be eradicated before they reduce grazing capacity.
Farmer should become familiar with key indicator species in their region to detect changes in veld condition. If necessary, they can then take corrective action using science-based guidelines.
Colour coding
A helpful way to visualise veld condition is with a traffic light system:
• Red: Dominance of unwanted pioneer plants – stop and reassess.
• Yellow: Subclimax species dominate – proceed with caution and monitor closely.
• Green: Increasing climax species – veld is in good condition and management is effective.
In the Free State and Northen Cape, rooigras would fall into the green group, various Eragrostis grasses in the yellow group, and three-awn and other annual grasses in the red group. Sourveld has its own sets of species.
More to read:
 | Roelof Bezuidenhout is a fourth-generation wool, mohair, mutton and game farmer and freelance journalist. Attended Free State University, majoring in animal husbandry and pasture science. Other interests include agricultural extension and rural development. |
