A5010335884- Plant nutrient uptake and metabolism
- Rangeland Management and Livestock Ecology
- Ecology and Vegetation Dynamics Studies
- Rangeland and Wildlife Management
- Mycorrhizal Fungi and Plant Interactions
- Soil Carbon and Nitrogen Dynamics
- Legume Nitrogen Fixing Symbiosis
- Plant Water Relations and Carbon Dynamics
- Fungal Biology and Applications
- Phytase and its Applications
- Plant Micronutrient Interactions and Effects
- Conservation, Biodiversity, and Resource Management
- Plant Stress Responses and Tolerance
- Agroforestry and silvopastoral systems
- Fire effects on ecosystems
- Wildlife Ecology and Conservation
- Forest Management and Policy
- Soil Geostatistics and Mapping
- Ruminant Nutrition and Digestive Physiology
- Plant responses to water stress
- African Botany and Ecology Studies
- Microbial Community Ecology and Physiology
- Pasture and Agricultural Systems
- Plant Pathogens and Fungal Diseases
- Data Mining Algorithms and Applications
University of Cape Town
2010-2024
Right to Care
2017-2022
South African National Biodiversity Institute
2010-2017
Ecological Society of America
2017
Stellenbosch University
2016
University of Hohenheim
1997-2001
Ben-Gurion University of the Negev
1993
While global deforestation induced by human land use has been quantified, the drivers and extent of simultaneous woody plant encroachment (WPE) into open areas are only regionally known. WPE important consequences for ecosystem functioning, carbon balances economies. Here we report, using high-resolution satellite imagery, that vegetation cover over sub-Saharan Africa increased 8% past three decades a diversity drivers, other than CO2, were able to explain 78% spatial variation in this...
Estimation and monitoring of soil organic carbon (SOC) stocks is important for maintaining productivity meeting climate change mitigation targets. Current global SOC maps do not provide enough detail landscape-scale decision making, allow tracking sequestration or loss over time. Using an optical satellite-driven machine learning workflow, we mapped (topsoil; 0 to 30 cm) under natural vegetation (86% land area) South Africa at m spatial resolution between 1984 2019. We estimate a total...
Rangelands face threats from climate and land-use change, including inappropriate change mitigation initiatives such as tree planting in grassy ecosystems. The marginalization impoverishment of rangeland communities their indigenous knowledge systems, the loss biodiversity ecosystem services, are additional major challenges. To address these issues, we propose wilder rangelands integrated framework, co-developed by South African European scientists diverse disciplines, an opportunity to...
It has been claimed that Holistic Planned Grazing™ (HPG), a type of rotational grazing, can increase productivity in rangelands and reverse climate change while doubling the stocking rate, mainly through impact densely bunched animals on primary production. Previous reviews have found similar or greater plant animal production continuous (season-long) compared with grazing. Here season-long grazing is HPG alone to explore evidence for impact. Three quantitative meta-analysis models were used...
Abstract Herbivory and fire are important drivers of ecosystem processes within African rangelands. We explore whether mid‐Holocene savannas were dominated by herbivory as a means cycling nutrients, perhaps played lesser role than today. Evidence from savanna ecology, paleoecology, historical literature indicates higher herbivore densities in pre‐colonial times compared to present. While may increase or decrease forage availability for herbivores, depending on the nutrient status...
SUMMARY The effects of NaCl salinity have been investigated with respect to the growth response, ionic content and gas exchange characteristics wheat plants ( Triticum aestivum L. cv. Gamtoos) raised on nitrate or ammonium nutrition at different Ca 2+ concentrations in nutrient medium. Salinity up 100 mM reduced biomass production, moisture water use efficiency both NO 3 − NH 4 + ‐supplied but production was a far greater degree than that wheat. There no clear trend photosynthetic response...
Proteaceae of the Cape Floristic Region, South Africa, transpire throughout summer drought, implying access to deep water. Hydraulic redistribution by Protea 'Sylvia' [P. susannae E. Phillips × P. exima (Salisb. Ex Knight) Fource; Proteaceae] was investigated in overnight pot and field experiments, where it hypothesised that (1) replenish water upper soil layers, (2) hydraulic facilitates nutrient uptake (3) shallow-rooted understorey plants 'parasitise' from proteas. Potted Sylvias...
Aspalathus linearis (Burm. F) Dahlg., Fabaceae is cultivated by small- and large-scale commercial farmers of the Cederberg Bokkeveld Plateau in Cape Floristic Region South Africa, for production an herbal beverage called 'rooibos' or 'rooibos tea'. Small-scale also harvest A. from wild market tea as organic fair-trade certified product. However, little known about apparent ecotypes linearis. We hypothesized that 1) rooibos are ecologically distinct (occurring different plant communities...
The contribution of hyphae Glomus mosseae (Nicol. and Gerd.) Gerd. Trappe (BEG 107) to the acquisition mineral nitrogen by Triticum aestivum L. cv. Hano (wheat) was tested under conditions low P high N (+N−P) or (−N−P). Mycorrhizal colonisation increased shoot dry weight plant tissue concentrations cations. However, mycorrhizal plants were not increased, although nitrate reductase activities significantly higher (in vivo activity) in +N−P compared non‐mycorrhizal roots. Severe deficiency...
This study compared the influence of \({\hbox{ NH }}_{4}^{+}\) or NO }}_{3}^{-}\) nutrition on contribution extraradical hyphae arbuscular mycorrhizal fungus Glomus mosseae (Nicol. and Gerd.) Gerd. Trappe (BEG 107) to uptake by Triticum aestivum L. 'Hano' (summer wheat) with sufficient insufficient N supply in semi-hydroponic culture. Roots root-distant were spatially separated compartmentalized pots. Although -fed plants supplied had higher concentrations than their counterparts, this did...
SUMMARY In wheat plants it was found that salinity stress (50 mM NaCl) and an increase in the exogenous Ca 2+ supply (to 5 mM) had a differential influence on N uptake capacity depending source (NO 3− or NH 4+ ). NO 3 − supplied which not been with supplemental calcium, of 50 NaCl reduced rate root by 30 %, F max 38 % concentration 35 %. 4 + (which were affected change calcium concentration) resulted reduction 16 (only root), while plant salt‐stressed wheat, 24 65 V uptake, 58% shoot per g...
The balance of papers in this Special Issue show that how Holistic Planned Grazing™ is managed and where it used impacts the efficacy approach. While we will do well to develop more mechanistic models can identify these thresholds test them real-life situations, certain broad generalisations not do. We neither dismiss Grazing out hand nor claim work anywhere. Both land-users scientists should consider evidence at along with their management goals (production, conservation or restoration)...
Rangeland management approaches, including rotational grazing, rely on assumptions about plant growth responses to the intensity, or severity (sward height) plus frequency, of defoliation. We tested these at farm, patch and scale using data from a grazing trial in an Eastern Cape mesic grassland South Africa along with field plot glasshouse pot experiments. The season-long (SLG), four-camp (FCG) holistic planned (HPG) equivalent stocking rates over three years. found that grass both potted...
Communal rangelands are a global resource of significant benefit to society through the provision critical ecosystem goods and services such as carbon sequestration, water livestock forage. The relative importance provided by communal is driven social environmental priorities range different stakeholders at local, regional national level. Understanding potential service trade-offs (and synergies) vital for making informed inclusive decisions part process stakeholder engagement, both in goal...