few types of ecosystems that are known by so many names: in the Midwest of the United States, they are known as prairies; in South America, they are called pampas, in Central Europe and Asia, they have been named steppes whereas in Africa they are referred to as savannas [1,2].
But perhaps this plethora of names should not surprise us: after all, grasslands occupy about a quarter of the Earth’s land, they can be found between forests and deserts and they exist on every continent except Antarctica.
They appear where rainfall is not quite enough to support the growth of a forest but it is also not so little for the land to become a desert. As a result, grass is the dominant form of vegetation in these areas.
In turn, these grasses and grass-like vegetation can support high densities of grazing animals, such as zebras, antelopes and bison. On top of that, these herds attract iconic predators, including lions and cheetahs.
So, grasslands are extremely biodiverse ecosystems. But they are also fragile ecosystems as water is scarce and they often depend on regular episodes of fire for renewal.
That is where we step in…
Today, however, most grasslands have been converted into agricultural land. This has caused several concerns. First and foremost, where humans have taken hold of grasslands to plant wheat, corn and other crops, native wildlife has been significantly reduced if not eliminated, as have other predator species.
For example, the bison has become almost extinct as settlers in North America converted much of American grassland into fields. In Little Missouri National Grassland in North Dakota, as many as 60 million bison once grazed these lands. Today only about 200,000 remain .
What is most concerning is that while grasslands have been seen as a prime area for development by humans, there has been no real recognition of their various benefits and services.
Premium land for agriculture
In the first place, humans can take advantage of grasslands to support quality livestock produce as grasslands provide an alternative to concentrate feed. At the same time, grasslands can be used to grow food directly for human consumption, such as cereals .
But these are only some of the goods and services that grasslands provide.
Grasslands come with even more important benefits
More importantly, these ecosystems play a fundamental role in:
- regulating our weather and climate
- supporting the nutrient cycle and water storage
- enabling pollination
- maintaining biodiversity
- preventing soil erosion
If grasslands are sustainably managed, then all the services and goods outlined above will continue to be provided like clock-work to the great benefit of humans.
How would sustainably managed grasslands operate and what we need to do?
In terms of water, the most important aspect for the successful sustainable management of grasslands is the management of water resources. Vast areas of grassland depend on the availability of water so that they can host grazing species or livestock.
Without water, the land would not be useable for livestock production development and animals would be limited to areas close to permanent sources of water only which is a cause of pasture. As a result, improvement of the water supply is pursued by creating water points or improving existing ones, and the clearing of undesirable vegetation to allow free access for stock and better grass growth .
Balanced vegetation composition
The unique vegetation of grasslands is also worth noting. Trees and shrubs are important features of many types of grassland but while some are very useful, others are invasive weeds and require vigorous management.
Trees provide valuable shade in hot climates and seasons and they give shelter in winter. Some trees are browsed and may be lopped for fodder – their fruits can also provide valuable feed. Where firewood is scarce, excessive cutting causes serious environmental damage due to the uprooting of sub-shrubs for fuel.
Woody vegetation is, however, often invasive, especially in tropical and sub-tropical conditions; bush encroachment is generally taken as a sign of poor management and overgrazing . As such, bush control is necessary in many cases.
To manage vegetation, a technique called clearing is employed extensively. This may involve some removal of stones, termite hills and other obstructions, but, for extensive grazing, clearing usually involves removing or thinning woody vegetation to improve access and grass growth or to reduce tsetse fly habitat.
Fire is the most common agent for clearing or controlling trees and shrubs. Controlled fire stimulates regrowth and supplies a green bite when most needed.
Burning of grassland must be carefully controlled and timed, otherwise it can cause serious damage; burning must take the whole ecosystem into account, not only the grass and the grazing livestock.
Ill-timed fire can have a devastating effect on wildlife, including nesting and young birds .