Alien flora of mountains: global comparisons for the development of local preventive measures against plant invasions
Article first published online: 26 OCT 2010
© 2010 Blackwell Publishing Ltd
Diversity and Distributions
Volume 17, Issue 1, pages 103–111, January 2011
How to Cite
McDougall, K. L., Alexander, J. M., Haider, S., Pauchard, A., Walsh, N. G. and Kueffer, C. (2011), Alien flora of mountains: global comparisons for the development of local preventive measures against plant invasions. Diversity and Distributions, 17: 103–111. doi: 10.1111/j.1472-4642.2010.00713.x
- Issue published online: 13 DEC 2010
- Article first published online: 26 OCT 2010
- biological invasions;
- invasion pathways;
- land use history;
- mountain ecosystems;
- non-native plant invasion
Aim We use data from 13 mountain regions and surrounding lowland areas to identify (1) the origins, traits and cultural uses of alien plant species that establish in mountains, (2) the alien species that are most likely to be a threat and (3) how managers might use this information to prevent further invasions.
Location Australia, Canada, Chile, India, New Zealand, South Africa, Spain, Switzerland, USA.
Methods Lists of alien species were compiled for mountains and their surrounding or nearby lowlands. Principal co-ordinates analysis was performed on a matrix of similarities created using presence/absence data for alien species. The significance of differences between means for (1) similarity metrics of lowland and mountain groups and (2) species traits of lowland and mountain alien floras was determined using t-tests. In seven of the 13 mountain regions, lists of alien species undergoing management were compiled. The significance of differences between proportions of traits for species requiring and not requiring management input was determined with chi-square tests.
Results We found that the proximal lowland alien flora is the main determinant of a mountain region’s alien species composition. The highest similarities between mountain floras were in the Americas/Pacific Region. The majority of alien species commonly found in mountains have agricultural origins and are of little concern to land managers. Woody species and those used for ornamental purposes will often pose the greatest threat.
Main conclusions Given the documented potential threat of alien species invading mountains, we advise natural resource managers to take preventive measures against the risk of alien plant invasion in mountains. A strategy for prevention should extend to the surrounding lowland areas and in particular regulate the introduction of species that are already of management concern in other mountains as well as climatically pre-adapted alien mountain plants. These may well become more problematic than the majority of alien plants currently in mountains.