A5083351044- Ecology and Vegetation Dynamics Studies
- Plant Water Relations and Carbon Dynamics
- Rangeland Management and Livestock Ecology
- Rangeland and Wildlife Management
- Botany and Plant Ecology Studies
- Hydrology and Watershed Management Studies
- Land Use and Ecosystem Services
- Remote Sensing in Agriculture
- Pasture and Agricultural Systems
- Soil erosion and sediment transport
- Conservation, Biodiversity, and Resource Management
- Soil and Unsaturated Flow
- Wildlife Ecology and Conservation
- Species Distribution and Climate Change
- Aeolian processes and effects
- Fish Ecology and Management Studies
- Climate variability and models
- Plant Taxonomy and Phylogenetics
- Freshwater macroinvertebrate diversity and ecology
- Agricultural Innovations and Practices
- Forest Management and Policy
- Tree-ring climate responses
- Botany, Ecology, and Taxonomy Studies
- Agroforestry and silvopastoral systems
- Aquatic Invertebrate Ecology and Behavior
Rhodes University
1982-2024
Agricultural Research Council of South Africa
2010-2021
Animal Production Institute
2010-2021
Nelson Mandela University
2011-2018
University of Technology Sydney
2006-2011
Forest Institute
2001
Cambrian Innovation (United States)
1999
University of Cape Town
1994-1999
Age Institute
1996
Future land cover changes may result in adjustments to biophysical drivers impacting on net ecosystem carbon exchange (NEE), catchment water use through evapotranspiration (ET), and the surface energy balance a change albedo. The Land Change Modeller (Idrisi Terrset 18.08) for 2000 2014 are used create future scenario of two with different management systems Eastern Cape Province year 2030. In S50E catchment, dualistic farming system, trend shows that grasslands represented 57% total area...
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...
ABSTRACT A new predictive modelling technique called the fuzzy envelope model (FEM) is introduced. The can be used to predict potential distributions of organisms using presence‐only locality records and a set environmental predictor variables. FEM uses logic classify variable maps based on values associated with presence combines results produce distribution map for target species. This represents several refinements approach in BIOCLIM package. These are related way which FEMs deal...
Daily and seasonal patterns of tree water use were measured for the two dominant species, Angophora bakeri E.C.Hall (narrow-leaved apple) Eucalyptus sclerophylla (Blakely) L.A.S. Johnson & Blaxell (scribbly gum), in a temperate, open, evergreen woodland using sap flow sensors, along with information about soil, leaf, micro-climatological variables. The aims this work to: (a) validate soil-plant-atmosphere (SPA) model specific site; (b) determine total depth from which uptake must occur to...
Leaf area index (LAI) is one of the most important variables required for modelling growth and water use forests. Functional–structural plant models these to represent physiological processes in 3-D tree representations. Accuracy depends on accurate estimation LAI at stand scales validation purposes. A recent method estimate from digital images (LAID) uses image capture gap fraction analysis (Macfarlane et al. 2007b) upward-looking photographs canopy LAID (cover photography). After...
In South Africa, the relative extent of range degradation under freehold compared to communal tenure has been strongly debated. We present a perspective on processes that drive rangeland land tenure. Our findings are based literature as well extensive field work both old lands and 'released' areas, where farms have transferred ownership. discuss patterns accompanied stewardship make recommendations direction policy should follow prevent further mediate rehabilitation existing degraded land.
The Leliefontein communal area in Namaqualand is grazed by mixed species herds that have multiple benefits for pastoralists. This study assessed how the management (herding and free-ranging) of different livestock affects their feeding ecology during wet dry seasons a semi-arid shrubland. By using direct observations grazing field, we established habitat preferences, diet selection resources overlap. Results indicate all free-ranging can be considered grazers with cattle being selective....
.__________________________________ Introduction ________________________________ Original and present taxonomic names of species. Stratigraphic distribution species ____________ Collection localities._________________________ Systematic descriptions.______________________ Literature cited____________________________ Index __-_-__-__---_--______________________ Page 55 57 58 59 82
SUMMARY The question of whether the diets twelve abundant macroinvertebrate taxa from middle and lower reaches Buffalo River (eastern Cape, South Africa) were too variable to allow them be assigned functional feeding groups (FFGs) was addressed. Spatial, temporal developmental variations in diet assessed. Foregut content analysis used as an index compare diets. contents compared early (small) late (large) instar larvae collected riffles at thirteen sites summer, riffles, stony backwaters...
2010, Klaus Hess Publishers, Sudetenland-Str. 18, 37085 Göttingen, Germany; and PO Box 90624, Windhoek, Namibia Hardcover, 3 volumes, XLIV + 1375 pp CD-ROM ISBN 9789991657301 (Namibia South Africa), 9783933117441 (Germany rest of the world). Price R600/€75
Increased woody plant density (woody encroachment or thickening) is a globally observed phenomenon. Similarly, increased atmospheric carbon dioxide concentrations and decreased pan evaporation rates are phenomena. In this paper, we propose that the former (increased density) product of latter. We stomatal conductance fixation arising from an enriched concentration, in conjunction with reduced evaporation, result density. suggest analogous to along rainfall gradients span arid mesic...
Abstract Eragrostis plana (Poaceae) is a perennial grass introduced from South Africa to the state of Rio Grande do Sul in southern Brazil. Currently, it considered an invasive several regions world, including America, where has caused negative ecological and socio‐economic impacts. Ecological niche models, using bioclimatic variables, are often used predict potential distribution species. In this study we prepared two models for E. Genetic Algorithm Rule‐set Production, first based on data...
Australian acacias have spread to many parts of the world. In South Africa, species such as A. mearnsii and dealbata are invasive. Consequently, more effort has focused on their clearing. a context increasing clearing costs, it is crucial develop innovative ways managing invasions. Our aim was understand biophysical properties in grasslands they relate grass production explore management implications. Aboveground biomass (AGB) determined using published allometric equation invaded northern...
ABSTRACT In South Africa, the relative extent of range degradation under freehold compared with communal tenure has been debated. This study presents findings from a ‘released’ area, where former farm was transferred to ownership in 1976 and compares this an ecologically similar still tenure. Analysis historical aerial photographs demonstrated increase 21·5 per cent shrub abundance at site after change (1975–1985), but slight decline 0·3 years preceding (1968–1975). Conversely, site,...
This paper explores the relationship between land cover change and albedo, recognized as a regulating ecosystems service. Trends relationships surface albedo were quantified to characterise catchment water carbon fluxes, through respectively evapotranspiration (ET) net primary production (NPP). Moderate resolution imaging spectroradiometer (MODIS) Landsat satellite data used describe trends at trajectory level. Peak season was computed reduce seasonal effects. Different found depending on...