Showing papers by "Barend F.N. Erasmus published in 2019"

How free-ranging ungulates with differing water dependencies cope with seasonal variation in temperature and aridity

Abstract: Large mammals respond to seasonal changes in temperature and precipitation by behavioural and physiological flexibility. These responses are likely to differ between species with differing water dependencies. We used biologgers to contrast the seasonal differences in activity patterns, microclimate selection, distance to potential water source and body temperature of the water-independent gemsbok (Oryx gazella gazella) and water-dependent blue wildebeest (Connochaetes taurinus), free-living in the arid Kalahari region of Botswana. Gemsbok were more active nocturnally during the hot seasons than in the cold-dry season, while wildebeest showed no seasonal difference in their nocturnal activity level. Both species similarly selected shaded microclimates during the heat of the day, particularly during the hot seasons. Wildebeest were further than 10 km from surface water 30% or more of the time, while gemsbok were frequently recorded >20 km from potential water sources. In general, both species showed similar body temperature variation with high maximum 24-h body temperature when conditions were hot and low minimum 24-h body temperatures when conditions were dry, resulting in the largest amplitude of 24-h body temperature rhythm during the hot-dry period. Wildebeest thus coped almost as well as gemsbok with the fairly typical seasonal conditions that occurred during our study period. They do need to access surface water and may travel long distances to do so when local water sources become depleted during drought conditions. Thus, perennial water sources should be provided judiciously and only where essential.

Fuelwood extraction intensity drives compensatory regrowth in African savanna communal lands

Abstract: LiDAR data collection was funded by the Andrew Mellon Foundation, the Council for Scientific and Industrial Research (CSIR) Strategic Research Panel and the Department of Science and Technology (DST). The CAO has been made possible by grants and donations from the Avatar Alliance Foundation, Margaret A. Cargill Foundation, David and Lucile Packard Foundation, Gordon and Betty Moore Foundation, Grantham Foundation for the Protection of the Environment, W. M. Keck Foundation, John D. and Catherine T. MacArthur Foundation, Andrew Mellon Foundation, Mary Anne Nyburg Baker and G. Leonard Baker Jr, and William R. Hearst III. B. F. N. E. is supported by the Exxaro Chairman's Fund. P. J. M. is funded by the DST/NRF Centre of Excellence in Tree Health Biotechnology and an NRF Innovation Scholarship (grant UID: 95030).

Climate change and control of diarrhoeal diseases in South Africa: Priorities for action.

Abstract: Weather conditions, especially temperature and precipitation, play a critical role in shaping patterns of diarrhoeal diseases. They determine the frequency of outbreaks, and the spatial and seasonal distribution of cases. Not surprisingly, it is anticipated that the burden of diarrhoeal diseases will escalate with climate change, in tandem with gradual increments in mean temperatures, but also during episodic heatwaves. The degree and nature of this escalation will, however, vary with the mix of pathogens in an area, the quality of sanitation services, food hygiene regulations and their enforcement, and the age structure of the population, among other factors. Understanding these patterns can inform the design of measures to prevent and control heat-related diarrhoea. In this editorial, we sum evidence on the heat sensitivity of enteric infections in South Africa (SA) and other parts of sub-Saharan Africa (19 studies), drawing on articles located in a systematic review (methods detailed in Manyuchi et al. [1]), and consider the implications of these findings for control of diarrhoea in SA in the context of climate change.