Effects ofSolanum mauritianumScopoli (bugweed) invasion on soil and vegetation in Vhembe Biosphere Reserve, South Africa

Abstract

This study examined the effects of Solanum mauritianum Scopoli (bugweed) invasion on soil properties and vegetation diversity and cover on three paired invaded and uninvaded sites in Vhembe Biosphere Reserve, Limpopo Province of South Africa. Soils were analysed for pH, total P, C, N and exchangeable cations of Na, K, Ca and Mg. In addition, soil moisture content, penetration resistance levels and soil water repellency were measured over three months. Vegetation diversity and cover were surveyed in plots measuring 10 9 10 m in both invaded and uninvaded sites. Results showed that soil pH, nutrient concentrations of total P, N, C, cations of K, Ca and Mg, soil penetration resistance levels and water repellency were significantly (P < 0.01) higher in the invaded than uninvaded sites. Soil moisture were significantly (P < 0.001) higher in the uninvaded than invaded sites. Vegetation diversity and cover were significantly (P < 0.01) lower in the invaded than uninvaded sites. Results indicate that bugweed invasion alters some soil properties and negatively impact native species diversity and cover. These results provide the first evidence in South Africa that bugweed invasion contributes to soil changes and vegetation displacement, therefore, the need to manage it through clearing.