Managing grasslands for biodiversity
Richard Lechmere-Oertel
NEWS
Current Address : Farmer ’ s Weekly Reprinted from : https :// bit . ly / 3B82qpn
South Africa ’ s grasslands cover approximately a third of the country from the eastern seaboard into the interior . They provide ecological infrastructure and economic benefits to a range of users , from families to municipalities and metropolitan centres . There are five Ramsar wetlands and three world heritage sites in South Africa ’ s grasslands .
Although grasses make up the dominant layer of the grassland , only one in six plants are actually grass species . Other plant types include bulbs and soft-leaved herbaceous plants ( collectively called forbs ), ferns , subterranean trees , shrubs and scattered trees or bush clumps . The non-grass component of this plant community has high conservation value , but is vulnerable to land use pressure .
Grasslands support diversity in all the major animal groups : mammals , birds , reptiles , amphibians and invertebrates . Stock farmers depend on the grassland biome for grazing and most of the country ’ s sheep and cattle are found here . Beef production has increased by almost 10 % during the past decade , yet the area under grazing has declined because of expanding human settlement , alien plant invasion , veld degradation , mining , crop farming and forestry .
Figure 1 . South Africa ' s grasslands cover approximately a third of the country .
Converting land use to cropping , mining or forestry significantly modifies an ecosystem . Livestock grazing also affects grasslands over time , but the changes are more subtle . As grazing and burning regimes change , grasslands can lose productivity and ecosystem function .
The resilience of grasslands
The deterioration of the grasslands deprives future generations of the benefits associated with this biome . However , it is not feasible for the state to purchase the land needed to meet grassland conservation targets . Alternative lowcost mechanisms to protect valuable grassland biodiversity include biodiversity-friendly grazing and burning programmes . These can improve livestock productivity and preserve grassland integrity .
Most unmodified grasslands are used for extensive livestock production , with fire and grazing the primary management tools . Any change in fire and grazing that supports more resilient grassland will better sustain livestock production and biodiversity , even in the face of climate change . Integrating biodiversity objectives with extensive livestock grazing management principles has a positive impact on the biome .
Burning and grazing guidelines
The South African Biodiversity Institute ( Sanbi ) has compiled best-practice guidelines for burning and grazing . These can be used by farmers with some technical understanding of grazing and burning . The information available covers agriculture and conservation issues and can help land managers and extension officers understand the principles of grassland ecology as they relate to grazing and burning management .
The guidelines give practical advice that can be applied at farm level to improve plant and animal conservation and maintain livestock production . The guidelines were developed from discussions with grassland ecologists , farmers , and biodiversity and grazing specialists . They represent the current best understanding of how to achieve the mutually beneficial objectives of sustainable livestock production , improved or stable veld and soil condition , and conservation of the grassland and its plant and animal species .
Grassland ecosystems
South Africa ’ s grasslands are resilient and stable ecosystems dominated by perennial plants that can withstand repeated defoliation or disturbance by fire , drought , frost and grazing . However , they are not invincible . Changes in plant vigour , species composition , vegetation structure and productivity occur in response to various management pressures , particularly inappropriate grazing and burning . These changes are highly undesirable in terms of biodiversity , livestock productivity and ecosystem functioning . But they are avoidable if the grassland is well managed .
Grasslands are found at a range of altitudes , from sea level to an altitude of above 3 000 m . They occur across various environments — from the sandy coastal plains and rolling hills of the eastern seaboard to the steep slopes , valleys and ridges of the sub-escarpment , up onto the plateaux of the high escarpment and the plains of the central Highveld . Across this landscape , 72 grassland vegetation types are recognised . They are differentiated from one another by shifts in species composition resulting from a complex interplay of environmental variables such as climate , topography , geology and soil .
Environmental patterns influence other ecological forces such as grazing and fire , which give rise to finer differen-
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