Reciprocal invasions in East Asia and eastern North America: shared phylogeography and ecology, contrasting invasion pathways

Univeristy of Connecticut, Storrs, CT, USA

East Asia and eastern North America share a large number of reciprocally introduced invasive plant species. Each region views many of these species as the most invasive and problematic of their naturalized alien flora. However, this seeming symmetry and the fact that both regions share strong phylogeographic linkages and are dominated by similar natural community types, belie the striking differences in life histories and functional traits of the worst invaders in each region. The most serious plant invaders in eastern North America tend to occur in and around forests and are perennial, woody, bird-dispersed species with moderate levels of shade tolerance. In stark contrast, the invasive species in East Asia originating from eastern North America are primarily short-lived herbaceous plants that colonize ruderal sites and the edges of croplands. Why this asymmetry occurs is not well understood despite past attempts to synthesize data. Using regional or county-wide databases of invasive alien species, we have been able to document and contrast differences among countries and between regions in the groups of species that have become invasive and their functional traits. We have supplemented this with remotely sensed data on land-use geometry and the history of introductions across countries. We can explain many of the dissimilarities in the invasive alien floras between regions by striking differences in: historical plant trade and associated international commerce, timing in alien plant introductions, horticultural landscape and cultural aesthetics, and current and past land-use patterns and geometry.

© 2012 Organizing Committee