Can High Density, Short Duration Grazing Replace Fire in a South African Mesic Grassland?

High density grazing (HDG), defined as the concentration of many livestock on a small area for a short period of time has become increasingly popular in the South African mesic grassland yet little is known about it impact. HDG is usually applied without fire, based on the assertion that it is a key contributor to desertification of grasslands. However, fire plays an important role in the development and growth of most South African mesic grassland plant species, as it stimulates resprouting and reduces competition for light. The aim of this study was to determine the impacts of high density grazing on plant species composition and soil physical properties in a South African mesic grassland. Using a fence-line contrast, the objectives were to compare the impact of HDG with annually burnt firebreaks; one which was grazed and the other one which was not grazed, on soil compaction, ground cover and species composition. Soils under HDG and annual burning with grazing were 54% and 32% more compacted, respectively compared to annual burning with no grazing. High density grazing compared to annual burning irrespective of grazing resulted in four-fold more litter accumulation that can reduce irradiation received by plants and limit growth. Grass species diversity was 10% lower under HDG and annual burning with grazing compared to annual burning with no grazing. Forb species diversity was similar between HDG and annual burning with no grazing. However, Jaccard’s dissimilarity index, showed a forb species turnover of 22%, with HDG having 3 and annual burn with no grazing having 2 unique species, indicating that fire dependent species may have been replaced with fire independent species under HDG. Findings from this study indicate that HDG cannot replace the role of fire and potentially has a negative impact on a South African mesic grassland

Impacts of invasive alien species on riparian plant communities in South-African savanna - data to the article

Data on plant species richness, Shannon's diversity, Pielou's evenness, and abundance (cover) of individual plant species in the plots

Strategies for managing complex social-ecological systems in the face of uncertainty: Examples from South Africa and beyond.

Improving our ability to manage complex, rapidly changing social-ecological systems is one of the defining challenges of the 21st century. This is particularly crucial if large-scale poverty alleviation is to be secured without undermining the capacity of the environment to support future generations. To address this challenge, strategies that enable judicious management of socialecological systems in the face of substantive uncertainty are needed. Several such strategies are emerging from the developing body of work on complexity and resilience. We identify and discuss four strategies, providing practical examples of how each strategy has been applied in innovative ways to manage turbulent social-ecological change in South Africa and the broader region: (1) employ adaptive management or comanagement, (2) engage and integrate different perspectives, (3) facilitate self-organization, and (4) set safe boundaries to avoid system thresholds. Through these examples we aim to contribute a basis for further theoretical development, new teaching examples, and inspiration for developing innovative new management strategies in other regions that can help address the considerable sustainability challenges facing society globally

Oral lipid-based nanoformulation of tafenoquine enhanced bioavailability and blood stage antimalarial efficacy and led to a reduction in human red blood cell loss in mice

Paula Melariri,1 Lonji Kalombo,2 Patric Nkuna,2 Admire Dube,2,3 Rose Hayeshi,2 Benhards Ogutu,4,5 Liezl Gibhard,6 Carmen deKock,6 Peter Smith,6 Lubbe Wiesner,6 Hulda Swai2 1Polymers and Composites, Material Science and Manufacturing, Council for Scientific and Industrial Research, Port Elizabeth, South Africa; 2Polymer and Composites, Material Science and Manufacturing, Council for Scientific and Industrial Research, Pretoria, South Africa; 3School of Pharmacy, University of the Western Cape, Bellville, South Africa; 4Centre for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya; 5Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya; 6Division of Pharmacology, University of Cape Town Medical School, Groote Schuur Hospital, Cape Town, South Africa Abstract: Tafenoquine (TQ), a new synthetic analog of primaquine, has relatively poor bioavailability and associated toxicity in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. A microemulsion formulation of TQ (MTQ) with sizes <20 nm improved the solubility of TQ and enhanced the oral bioavailability from 55% to 99% in healthy mice (area under the curve 0 to infinity: 11,368±1,232 and 23,842±872 min·µmol/L) for reference TQ and MTQ, respectively. Average parasitemia in Plasmodium berghei-infected mice was four- to tenfold lower in the MTQ-treated group. In vitro antiplasmodial activities against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum indicated no change in half maximal inhibitory concentration, suggesting that the microemulsion did not affect the inherent activity of TQ. In a humanized mouse model of G6PD deficiency, we observed reduction in toxicity of TQ as delivered by MTQ at low but efficacious concentrations of TQ. We hereby report an enhancement in the solubility, bioavailibility, and efficacy of TQ against blood stages of Plasmodium parasites without a corresponding increase in toxicity. Keywords: microemulsion, solubility, G6PD deficiency, in vivo efficac