Plant invasions in alpine habitats: insights into altitudinal patterns and mechanisms from the dandelion invasion in the Chilean Andes

Background/Question/Methods Most studies on invasive species have been carried out in highly modified lowland environments, and little attention has been directed to less disturbed, high elevation habitats. However, over a thousand non-native species have become naturalized in natural areas at high elevations worldwide, and their spread may pose a significant threat to these vital ecosystems. Thus, it seems worth to ask which factors determine their success. In this study, we analyzed the factors involved on the distributions of non-native plant species along altitudinal gradients in the central Chilean Andes. Furthermore, taking advantage of the wide altitudinal distribution of the invasive non-native species Taraxacum officinale (dandelion) in the Andes of central Chile, we experimentally assessed the role of disturbance, soil characteristics and biotic interactions in the success of this invasive species.

Results/Conclusions Multivariate analyses indicate that while temperature (particularly freezing temperatures) is the most important factor correlated with the altitudinal distribution of native species, soil nutrients (nitrogen and potassium) are the most important factors correlated with the altitudinal distribution of non-native species. For T. officinale, positive interactions with native species are key in the success of this invasive species, with the importance of this interaction increasing with elevation. Positive interactions are highly species-specific, where the abiotic soil characteristics control the success of T. officinale. Experiments simulating future climate change scenarios indicate that under warmer conditions positive interactions are not longer important at very high elevation but highly relevant at lower elevations. These results open new questions about the role of native vegetation on mitigating the spread of invasive species on the future.