Journal of Ecology

Volume 96 Issue 1 Page 46-57, January 2008

To cite this article: Philip W. Lambdon (2008) Is invasiveness a legacy of evolution? Phylogenetic patterns in the alien flora of Mediterranean islands
Journal of Ecology 96 (1) , 46–57 doi:10.1111/j.1365-2745.2007.01324.x

Abstract

Is invasiveness a legacy of evolution? Phylogenetic patterns in the alien flora of Mediterranean islands

Philip W. Lambdon* *Correspondence and present address: Global Programmes Department, Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire SG19 2DL, UK. E-mail: plambdon@googlemail.com.

NERC Centre for Ecology and Hydrology, Hill of Brathens, Banchory, Aberdeenshire, AB31 4BW, UK

*Correspondence and present address: Global Programmes Department, Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire SG19 2DL, UK. E-mail: plambdon@googlemail.com.

Key-words: biological invasions, cladistic relationships, macro- vs. microevolution, relatedness measures, screening protocols, taxonomy, trait analysis.

Summary

1.	The Mediterranean region has been invaded by a wide range of introduced plant species which differ greatly in their ecology, morphology and human utilization. In order to identify a suite of traits which characterize invasiveness, recent studies have advocated the use of evolutionary relationships to unravel highly confounded influences.
2.	This study attempts to identify an evolutionary component to invasiveness and other complex invasion-related traits in the Mediterranean alien flora using an autocorrelation technique, the ‘phylogenetic association test’. I compared a traditional hierarchical taxonomy with the recent phylogeny of the Angiosperm Phylogeny Group.
3.	Invasiveness did not have a significant phylogenetic component. Any weak clustering was generally at the genus level.
4.	Several associated ‘meta-traits’ (high introduction frequency, adaptation to several habitat types and favourability for different modes of introduction), exhibited stronger phylogenetic components. Although each of these conveys some of the attributes of invasiveness, their clustering patterns differed considerably, suggesting that they arise from independent evolutionary pressures. Furthermore, within each meta-trait, different clusters may have been selected for different reasons.
5.	Other reasons for the lack of a detectable evolutionary component to invasiveness are discussed. Firstly, the results of our test simulations suggested that incorrect phylogeny could result in a moderate degree of error. Secondly, over evolutionary time, complex or stochastic events such as ecosystem change could radically alter the adaptive advantages of particular traits.
6.	Synthesis. Since invasiveness has little phylogenetic component, I argue that it is less likely to be predictable from as yet unidentified traits in any simple way. Although trait syndromes could develop without leaving a phylogenetic pattern, its absence probably indicates that the dominant selective forces are responses to short-term ecological shifts, and a greater mechanistic understanding of these is needed.

This article is cited by:

Philip W. Lambdon. Why is habitat breadth correlated strongly with range size? Trends amongst the alien and native floras of Mediterranean islands. Journal of Biogeography doi: 10.1111/j.1365-2699.2008.01894.x
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