The southwest Kalahari dune field does not emit dust post‐fire despite a lack of vegetation and above‐threshold winds

Journal article

Vegetated sand dunes are not typically considered to be significant sources of dust because of coarse grain sizes and high vegetation cover. Yet, plumes of dust have been observed from vegetated dune fields, and wind tunnel experiments show the potential for interdunes to emit dust. The partially vegetated southwest Kalahari is one such dune field that is vulnerable to climate‐driven land degradation and vegetation cover change and has been posited as a potential future dust source. In this study, we monitor the post‐fire de‐vegetated state of 11 interdunes to investigate the dust emission potential and erodibility controls on emission. Findings suggest that there is little emission of dust despite a fine‐grain component (up to 30% of resident grains <62.5 μm) and a lack of vegetation, even with high velocity wind events (>7 m s−1) post‐fire. Erosive wind events were less frequent compared to other dust‐producing regions, with wind speeds generally under 7 m s−1. Five high wind speed events over 7 m s−1 were recorded in September 2022, the month immediately following burning, but even then, only one event had a concurrent increase in aerosol concentration. This is indicative of other erodibility factors limiting dust emission. These include high (>50%) burned debris cover in the immediate post‐fire period and evidence of biological soil crusts that survived burning. Both protect the surface after fire whilst the natural vegetation cover recovers. Combined, the general low wind speeds, high initial surface cover, and the protective effect of biocrusts result in a low probability of the southwest Kalahari emitting dust post‐fire. However, fine‐grain sizes and low vegetation cover under drought and high grazing may lead to conditions conducive for dust emission.

Authors: Huck, RA; Thomas, DSG; Wiggs, GFS

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Earth Surface Processes and Landforms
• Volume: 51
• Issue: 2
• Article number: e70258
• Publication date: 2026-02-05
• Acceptance date: 2026-01-21
• DOI: 10.1002/esp.70258
• EISSN: 1096-9837
• ISSN: 0197-9337
• Language: English
• Keywords: fire; wind erosion; savanna biogeomorphology; sand dunes; mineral dust; biological soil crusts