Climate change has intensified extreme weather events worldwide, such as droughts, which have severely affected South Africa’s rangelands by reducing productivity and increasing livestock mortality. This study aimed to investigate variability in grazing capacities and stocking rates with respect to land tenure, long-term grazing capacity norms, field surveys, and farmer perceptions during and post-drought conditions in the three biomes in South Africa. In-person interviews and field surveys were conducted with 85 farmers from the Grassland (n = 25), Savanna (n = 35), and Nama-Karoo (n = 30) biomes and vegetation condition was surveyed during or after the drought. Grazing capacity did not differ significantly across land tenure systems in the Savanna biomes (p > 0.05), but significant differences were found in the Grassland and Nama-Karoo biomes (p< 0.05). Over > 60% of farmers in the Nama-Karoo biome rated their rangeland condition as poor because of the drought, and field surveys showed that grazing capacities were four times lower than the national recommended grazing capacity norm. Considering the high inter-annual variability in vegetation productivity and differences in farmers’ perceptions based on local knowledge, it is recommended that the Department of Agriculture adopt flexible grazing capacity ranges in the regulations of the Conservation of Agricultural Resource Act 43 of 1983.

Most studies suggest that multiple factors are responsible for woody plant encroachment, but are inconclusive on its causes. Woody plant encroachment is modified by local patterns of disturbance, topography, soil texture and fertility, and their relative importance and interaction strength varies among locations. We used grassland communities, Carletonville Dolomite Grassland (CDG), Rand Highveld Grassland (RHG) and abiotic factors (Soil Organic Carbon (SOC), Total nitrogen (TN), Phosphorus (P), Potassium (K), Sodium (Na), Calcium (Ca), Magnesium (Mg) and pH) to investigate habitat preferences of Seriphium plumosum L. in South African semi-arid grassland. Grassland community had a significant effect on S. plumosum density, canopy size, and on components of soil fertility (P< 0.05). Slope position had a significant effect on S. plumosum density and canopy size (P< 0.05). Seriphium plumosum density was significantly lower (23 plants/50 m²±2.39 (SE)) in CDG than in RHG (40 plants/50 m²±4.19). By contrast, S. plumosum canopy size was significantly higher (1.39 m²±0.11) at CDG than at the RHG (1.06 m²±0.08). The interaction of grassland community and slope position had a significant effect on S. plumosum density and soil sodium content (P< 0.05). Bottom slope regions in RHG (59.00 plants/50 m²±8.62) had higher S. plumosum density than bottom slope regions (19.75 plants/50 m²±3.01) in CDG. Soil sodium content was similar in CDG slopes and higher than in RHG slopes. Seriphium plumosum density was positively related to components of soil fertility; P (r² = 0.1270; P 0.0036), K (r² = 0.0786; P 0.0237), Na (r² = 0.0686; P 0.0350), Ca (r² = 0.0681; P 0.0358), and SOC content (r² = 0.0669; P 0.0374). However, Seriphium plumosum canopy size did not show any relationship with components of soil fertility. This study revealed that S. plumosum density in grassland communities increased with increasing soil texture and fertility.

Seriphium plumosum L. is an indigenous unpalatable shrub that occurs in fire-prone semi-arid South African grassland areas, yet research proposes the use of fire to control its encroachment of rangelands. This study investigated the interaction effects of burning and soil depth on components of soil fertility. Soil samples were collected from the surface (10 ≤ 20 cm) soil, before and after burning in randomly selected paired subplots (25 m × 25 m), with six replicates. Data was analysed as a randomised complete block design, with repeated measures (before and after burning) in a 2 × 2 factorial analysis of variance (ANOVA) using generalised linear model (GLM) procedures. Components of soil fertility measured (K, Ca, Mg, Org C, P, pH and TN) showed a significant decrease with increasing soil depth both before and after burning, except for K and P, which were significantly higher in surface soils after burning. The results showed that the response of soil nutrients to fire depends on the temperature tolerance threshold of individual soil nutrient elements. Increasing surface soil available K and P concentrations after burning may improve the conditions for S. plumosum encroachment, with implications for similar environments and species worldwide.

Approximately 590,000 km2 of rangelands were severely affected by drought, leading to a significant decline in rangeland productivity and an increase in livestock mortality across South Africa. This study aimed to understand variability in grazing capacities and stocking rates regarding land tenure, long-term grazing capacity norms, field surveys, and farmer perceptions under and post-drought conditions in the three biomes in South Africa. In-person interviews and field surveys were conducted with 85 farmers; Grassland (n=25), Savanna (n=35), and Nama Karoo (n=30) biomes during a drought period were interviewed, and vegetation condition was surveyed after a drought period. Grazing capacity did not differ significantly across land tenure systems in the Savanna biomes (p>0.05), but significant differences were found in the Grassland and Nama-Karoo biomes (p< 0.05). Over >60% of farmers in the Nama-Karoo biome rated their rangeland condition as poor due to the drought, and field surveys showed that grazing capacities were four times lower than the national recommended grazing capacity norm. The study concluded that the Department of Agriculture should adopt flexible, climate-responsive grazing capacity guidelines since the current and fixed grazing capacity norms do not account for the sharp decline in grazing capacity during drought.