Termite mound impacts on hydrology vary with herbaceous vegetation and topsoil texture

Abstract

There are many termite mounds in African savannas, where their interactions with vegetation and their potential role in redistributing water are of significant interest for ecosystem function and services. Here we focus on termite mounds as structural components of the environment and sample both bare and grassy termite mounds across a topsoil texture gradient to assess mound hydrological properties and to explore the potential for termite mound-mediated water redistribution to affect vegetation growth in water-limited savanna systems. We found mound vegetation cover has distinct and opposing effects on water infiltration rates; bare mounds consistently slow infiltration rates across the topsoil texture gradient, whereas infiltration on grassy mounds is faster and more variable, particularly in finer-textured topsoil. Given the consistently slow infiltration rates on bare mounds, we infer that bare termite mounds have the potential to redistribute water locally during rainfall events, and suggest this may be partially responsible for inhibiting vegetation colonization of the mound, while having potentially beneficial consequences for mound-adjacent vegetation.