Determining the role and relative importance of predator avoidance and nutrition as processes influencing herbivore utilisation of burnt areas in Satara, Kruger National Park, South Africa

[摘要] This study aimed to determine the role and relative importance of predator avoidance andnutrition as processes influencing herbivore utilisation of burnt areas, at Satara, KrugerNational Park by using variation in fire size and fire season. The driving factors investigatedincluded forage quality, forage quantity, vegetation structure and predation risk.The effect of fire size and season on the landscape was tested by recording grass height,greenness, grass nutrient sampling and visibility. Results showed that fire size and seasonhad a significant impact on the physical environment by decreasing grass/forage quantitypost-fire but increasing grass/forage quality. Over time the plots returned to near pre-fireconditions, with forage quantity increasing (grass height and biomass) and forage qualitydecreasing (nitrogen availability). Visibility increased immediately post-fire, more significantlyin regards to herbivores with their heads in a 'head-down/grazing” position than in a 'headraised/vigilant” position. As with forage quantity and quality, visibility returned to near pre-fireconditions at the end of the study sampling period. The response of animals to thesechanges in the environment was recorded through dung counts, camera traps andbehavioural observations. I found that there was increased use of burnt plots post-firethrough comparing herbivore presence on plots burned in different sizes and seasons,day/night utilisation of plots, and using behaviour data I could determine to what extentforage and predation risk were driving the use of burnt areas. I focused on three herbivorespecies (Aepyceros melampus, Connochaetes taurinus and Equus quagga) which varied interms of body size digestive systems, forage type, and social behaviour. As expected, Ifound that predation risk did appear to be more important in driving the behaviour of thesmaller-bodied herbivores but both nutrient requirements and susceptibility to predation wereshown to play a role in explaining the use of burnt areas for all three herbivore species.Variation between plots in environmental factors such as tree density, forb percentage anddistance to water, were found to be not significant and thus did not confound our results

[发布机构] University of the Witwatersrand