Assessing water use by Prosopis invasions and Vachellia karroo trees: Implications for groundwater recovery following alien plant removal in an arid catchment in South Africa

•There was no significant difference in the sap flux density of V. karroo and Prosopis.•Adverse impacts of Prosopis invasions on groundwater are due to high plant density.•There was evidence of hydraulic redistribution in the root zone of Prosopis trees.•Groundwater recovery is low in catchments where Prosopis is replaced by dense V. karroo stands.