Enhanced soil nutrient concentrations beneath-canopy of savanna trees infected by mistletoes in a southern African savanna

• Soil nutrient concentrations were greater beneath host than non-host trees.
• Soil nutrient concentrations increased by a factor ranging between 1.41 and 39.
• The increase varied among tree species being greatest in Ficus sycomorus.
• Mistletoes increase nutrient availability in semi-arid savanna.
• Mistletoes increase spatial heterogeneity of nutrient availability.

Mistletoes have a major influence on nutrient dynamics in nutrient-poor ecosystems with potential to contribute to nutrient enrichment beneath tree-dominated patches. We studied the soil nutrient concentrations beneath four tree species with and without mistletoe infections. Effects of species and infection status on soil nutrient concentrations were tested using a general linear model (GLM). Soil nutrient concentrations differed with tree species, infection status and their interaction (p < 0.05). The concentrations of nitrogen (N) and phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) were elevated beneath Sclerocarya birrea and Diospyros mespiliformis, respectively. Soils beneath host trees had higher nutrient concentrations and were slightly alkaline than those beneath non-host trees. The concentration of soil nutrients increased by a factor ranging from 2.25 for N, 2.28 for P, 8.55 for Ca, 3.78 for Mg up to 39 for K. The increase in below-canopy soil fertility with mistletoe infection leads to an increase in the spatial heterogeneity of nutrient availability with potential to alter ecological factors such as species diversity and plant productivity. In conclusion, we suggest that nutrient enrichment in tree-dominated patches and associated increase in resource heterogeneity play an important role in determining ecosystem structure and function in semi-arid savanna.