Hydrologic response to land use/cover changes and Pteronia incana shrub invasion in Keiskamma catchment, Eastern Cape Province, South Africa

Abstract

The Keiskamma catchment has undergone significant land use/cover changes (LUCC) and invasion by Pteronia incana (P. incana) shrub, and the hydrological implications of the phenomena are not fully understood. This study assessed the hydrological response of the catchment using remote sensing per-pixel classification, the SWAT model between 1994 and 2016, and field experiments. Results revealed a significant increase in woody vegetation encroachment and a decrease in mean annual streamflow, runoff, soil water content, evapotranspiration and groundwater. However, high surface runoff, and sediment loss were evident under P. incana invader shrub at hillslope scale. The study concludes that the hydrological response of the catchment was influenced significantly by LUCC in the form of extensive invader shrub encroachment, expansion of exotic forest tree species, impoundments and infestation of riparian zones by invasive vegetation. Control of alien invasive plants and utilization of indigenous forest species are recommended for catchment management.

Keywords:

• Hydrological response
• land use/cover changes
• Pteronia incana
• SWAT model
• Keiskamma catchment

Acknowledgments

The authors acknowledge everyone and every institution which has offered support to this research. This work is based on the research supported in part by the National Research Foundation of South Africa (Grant Numbers: 114457), the Nelson Mandela University and Dormehl Cunningham Scholarship. The opinions, findings and conclusions or recommendations expressed in this paper publication generated by the NRF-supported research are those of the authors. The NRF accepts no liability whatsoever in this regard.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

Data is available upon request.