Abiotic conditions shape the relationship between indigenous and exotic species richness in a montane biodiversity hotspot

Abstract Montane ecosystems are more prone to invasions by exotic plant species than previously thought. Besides abiotic factors, such as climate and soil properties, plant-plant interactions within communities likely affect the performance of potential invaders in their range. The biotic resistance hypothesis predicts that high indigenous richness hampers invasions. acceptance hypothesis, on other hand, a positive relationship between richness. We tested these two hypotheses using observational data along an elevational gradient southern African biodiversity hotspot. Species composition plants were recorded 20 road verge plots 1775–2775 m a.s.l. Drakensberg, South Africa. Plots 2 × 50 size positioned at intervals. found negative correlation for locations with poorly developed mineral soils, suggesting through competitive interactions. A strong very shallow soils elevations indicated lack possibility facilitating harsher environments. These results suggest is restricted lower mid while prevails presence severe stress, potentially increasing risk into montane hotspots.