Fig. 6 Relationships between the fractional vegetation cover (FVC), and (a) temperature and (b) precipitation. Relevance analysis between the different FVC, and (c) temperature and (d) precipitation.
In general, FVC in southern Africa increased from west to east (Fig. 7a). The areas with higher FVCs were in the subtropical monsoon climate zone of eastern South Africa. The marine climate zone in the south and the western coastal areas with sparse vegetation also suffered from severe soil erosion. Vegetation can reduce near-surface wind speed, intercept moving sand particles, and protect and fix the topsoil. Furthermore, an increase in FVC effectively helps to slow down soil nutrient loss, reduces dust entrainment, and inhibits soil wind erosion (D. Li et al., 2018; Yan et al., 2013). The data showed that FVC was significantly negatively correlated with soil wind erosion across 47.2% of southern Africa (Fig. 7b). These areas were mainly distributed in the Kalahari Basin in the central part of the study area where FVC was around 0.4. The FVC is also strongly affected by temperature and precipitation (Figs. 6a, 6b). Therefore, the influence of temperature and precipitation on the soil wind erosion modulus may be related to different FVC values. The soil wind erosion modulus is strongly affected by the FVC when the FVC has a strong correlation with temperature and precipitation in an area. That is to say, the changes in temperature and precipitation have a more noticeable impact on soil wind erosion in these areas.