What grazing gradients and fence-line contrasts reveal about grazing pressure in montane grasslands

By Thami Shezi, MSc Student, SAEON Grasslands-Forests-Wetlands Node Tweet

Figure 1. A kraal site in one of the villages in QwaQwa where most of the grazing is intense around a kraal (piosphere)

Montane grasslands provide goods and services to sustain everyday life for communal and urban communities.

These grasslands are a source of water, provide food for livestock and serve as an economic incentive for the rural communities as grass is used in the production of thatched roofs and household goods (bowls, mats, brooms and hats).

Livestock grazing plays an important role in montane grasslands. Over the last decades these grasslands have been subject to intense grazing pressure. In other areas of South Africa, the intensity of livestock grazing has been associated with the degradation of grasslands, especially in communal rangelands.

I wanted to understand the impacts of livestock grazing on plant species diversity and composition in this system and how these compare with less utilised sites in protected areas. My MSc project focused on two objectives. The first was to assess whether a gradient of grazing pressure exists from kraal sites and, if so, whether this was impacting plant species diversity and composition (Figure 1). The second objective was to assess the impacts of livestock grazing on plant species diversity and composition using a fence-line contrast between communal areas and protected areas (Figure 2).

The project was based in the northern Drakensberg (Thabo Mofutsanyane district in the eastern Free State) and situated in two national parks and two communal areas paired as follows: Royal Natal National Park (RNNP) KwaZulu-Natal and Witsieshoek communal area (Figure 2), Golden Gate Highlands National Park (GGHNP) and QwaQwa communal area (Figure 3) and Witsieshoek Community Conservation Area (WCCA).

Figure 2. Fence-line contrast between Royal Natal National Park (left) and Witsieshoek communal area (right) Figure 3. Fence-line contrast between Golden Gate Highlands National Park and QwaQwa communal area

For the first objective I set up transects from kraal sites, extending away from these with increasing distance. The pairs of protected area-communal sites were then used as fence-line contrasts to explore the impact of livestock grazing on plant species diversity and composition in these different land uses. Soil samples were taken to analyse the impact of livestock grazing pressure on the physical properties of the soil.

Findings

More than 320 indigenous plant species were recorded across all four sites. The highlights were finding some of the endemic species the Drakensberg is renowned for, such as Aster pleiocephalus, Helichrysum krebsianum, Selago monticola, Thunbergia vernosa and Vernonia thodei.

The highest number of species, 107, were recorded in RNNP, with 81 in communal areas. This indicated that despite a long history of communal livestock grazing, these communal areas still contribute to biodiversity conservation. However, this contribution may be compromised if current grazing pressure is maintained.

The impact of grazing pressure with distance was not that pronounced, in fact it was negligible. This can be attributed to spatial heterogeneity and that the area has been hammered by livestock for decades, which may have disguised a gradient of grazing pressure.

Figure 4. Brunsvigia radulosa (left), one of the species that gets taken down by animals quickly, and Orchid sp. (right), one of the iconic species of the Drakensberg montane grasslands

The RNNP/Witsieshoek pairing showed clear patterns in terms of species richness and composition on either side of the fence, with the RNNP displaying the highest diversity. Surprisingly, the GGHNP/QwaQwa communal area showed no clear patterns in species richness and composition. This can be attributed to the fact that, historically, GGHNP used to be a farm that was heavily grazed and has only been protected for the last 30 years.

In the RNNP KwaZulu-Natal and Witsieshoek communal area comparison, the state of the grassland on the RNNP side of the fence-line contrast may present a benchmark grassland state that could be achieved in this communal grazing region if conservative livestock numbers can be maintained.

Lessons learned

The project was a steep learning curve, not only in terms of the study itself, but also in liaising with local chiefs and the community. Lessons learned from the study are that flexible and integrated methods are needed to maintain this grassland biodiversity.

Figure 5. SAEON field technician Siphiwe Mfeka marks a GPS point in one of the plots

The area will continue to be a natural resource (grazing) for livestock and for the community. Until now the grasslands have shown themselves to be resistant to the significant impacts of livestock grazing, but with the prospect of unknown changes brought about by climate change, this may soon change. We are cautioned by the lack of recovery in the GGNP that once species are lost, they may not easily recover in these grasslands.

Acknowledgements

The project would not have been possible without funding from the Department of Science and Technology, the National Research Foundation and the SAEON Grasslands Node. I would like to thank the QwaQwa tribal council, SANParks, Cedara Soils Analytical Services Laboratory, the SANBI KwaZulu-Natal Herbarium, Ezemvelo KZN Wildlife, Wits University, University of KwaZulu-Natal and the South African Weather Service for their support.

I am greatly indebted to Prof. Timothy O’ Connor, Prof. Ed Witkowski, Dr Erwin Sieben and Sue van Rensburg, the coordinator of SAEON’s Grasslands-Forests-Wetlands Node, for their support and encouragement, as well as to SAEON field technician Siphiwe Mfeka and everyone else who assisted me with fieldwork.