South African grasslands are rich in flora and have co-evolved with fire. Fires have been the primary tool used to manage grasslands for livestock production for many years, however, there is debate about how they impact and alter landscapes. There are two schools of thought in the literature, one that states fires are detrimental to landscapes, causing excess soil erosion and changing soil properties, and the other being that fires are beneficial to ecosystems, maintaining vegetation structure, preventing bush encroachment, cycling nutrients, and allowing for new plant growth. This study focused on the effects of Fire Return Intervals (FRI) on soil properties in order to better understand the role that fire plays in geomorphic processes in the upper Tsitsa River catchment. Fire frequency was determined using Landsat satellite imagery, and testing was carried out at 60 sites on soils exposed to different FRIs. It was found that soils that were exposed to a high fire frequency (1-2-year FRI) exhibited a higher degree of water repellency than soils that were exposed to a low fire frequency (3-4 year FRI). The degree of soil water repellency between the sites was not significant, showing that fires are not affecting soils to the degree previously thought and that literature might suggest. There are multiple variables to consider, however, results suggest that fires may not be as detrimental to soil properties and erosional factors in the Tsitsa catchment as previously thought, and erosion may be a product of grazing practices and soil type.
Audio/Video, Conference Presentation, SER2019
Society for Ecological Restoration