COS 59-2 - The true drivers of non-native plant invasion in mountains

Wednesday, August 10, 2016: 1:50 PM
Floridian Blrm A, Ft Lauderdale Convention Center
Jonas J. Lembrechts1, Aníbal Pauchard2, Jonathan Lenoir3, Martin A. Nuñez4, Charly Geron5, Arne Ven1, Ivan Nijs1 and Ann Milbau5,6, (1)Department of Biology, University of Antwerp, Wilrijk, Belgium, (2)Universidad de Concepción, Laboratorio de Invasiones Biologicas (LIB), Instituto de Ecología y Biodiversidad (IEB), Concepción, Chile, (3)Department of Ecologie et Dynamique des Systèmes Anthropisés, Université de Picardie Jules Verne, Amiens, France, (4)Grupo de Ecología de Invasiones, Instituto de Investigaciones en Biodiversidad y Medioambiente, CONICET, Bariloche, Argentina, (5)Climate Impacts Research Centre, Umeå University, Abisko, Sweden, (6)Department of Biodiversity and Natural Environment, Research Institute for Nature and Forest INBO, Brussels, Belgium
Background/Question/Methods

Scientific interest in plant invasions in mountains is growing, together with the global exponential increase in these invasions. Current research mostly consists of observational studies, with only limited information from experiments, leaving important questions about the roles of and interaction between all possible drivers of mountain invasion unanswered. We integrate human-mediated (i.e. disturbance, nutrient addition and propagule pressure) and climatic factors into one multi-factorial cross-continental experiment to disentangle their roles in driving or limiting plant invasions. With this experiment along elevation gradients from lowlands to the alpine zone in two high-latitude regions in Sweden and Chile, we shed light on the possibilities for invaders at the invasion front in cold environments. 

Results/Conclusions

We show how virtually all measures of invader success showed a quadratic correlation with elevation, with competition being the main limitation for invasions at low elevation and cold climate reducing invader success at high elevations. Disturbance turned out to be the main driver of invader success besides elevation, with high nutrient levels playing an additional role in biomass and flower production. The role of propagule pressure was neglegible, especially towards later stages of invader development. We thus argue that mountains are likely to see rapid increases in plant invasions in the near future, as disturbance and human influence are on the rise in mountains. Our results however suggest that invasion is unlikely if both conditions are not met, suggesting that we might be able to keep undisturbed mountain areas invasion free. It will thus be a question of limiting the uncontrolled expansion of anthropogenic disturbance in mountains to contain mountain invasion within reasonable limits.