RANGELAND RESTORATION
New Paper Points to Rangeland-friendly Grazing Approach
A new paper co-authored by Conservation South Africa (CSA) Director of Science and Research Heidi-Jayne Hawkins provides new insights on grazing approaches to optimize rangeland management and restoration.
Previous work by the scientist and others established that intensive grazing (or holistic planned grazing), with high animal densities, generally confers no advantage over simple, rotational grazing approaches. This is good news for rural farmers in South Africa who traditionally have a simple two- or four-camp approach, where the village head will designate an area to be ‘rested’ while another can be grazed by livestock.
This latest paper, published in the African Journal of Range and Forage Science in July, went further to see whether high soil nutrients would mitigate the effect of intensive grazing on grass growth (in line with the so-called Compensatory Continuum Hypothesis). Indeed, they found that intensive grazing can enhance grass growth but only in soils with relatively high nutrient status and only under moderately intensive grazing regimes. This speaks to a nuanced approach where the grazing manager adjusts their approach based on the ecology of the area.
Rangeland management approaches, including rotational grazing, rely on assumptions about plant growth responses to the intensity, or severity plus frequency of defoliation (removal of grass parts, usually leaves, by cutting or grazing) of grazing. Intensive or holistic planned grazing attempts to mimic natural migrating herds, such as wildebeest.
“Managers who are able to manipulate grazing frequency and severity using forms of high intensity rotational grazing should aim to maximise grazing frequency on nutrient-rich soils, and grazing recovery on nutrient-poor soils,” concludes the study conducted over 3 years in an Eastern Cape grassland of South Africa with moderate moisture in addition to field plot and glasshouse pot experiments.
The lead author of the study is Zander Samuel Venter, now employed at Norwegian Institute for Nature Research, and former PhD student of Heidi and the other co-author, Michael D. Cramer of the University of Cape Town at the time the work was completed.
As part of its work to restore degraded communal rangelands, CSA conducts scientific research on grazing, fire and erosion management approaches to see how local communities can increase plant and animal productivity and soil carbon sequestration on rangelands while maintaining biodiversity.
