Invasiveness of alien plants in Brussels is related to their phylogenetic similarity to native species

Increasing globalization and human mobility have facilitated the intentional and unintentional introduction of species beyond their natural geographic ranges. Such alien species are considered to be a main driver of global biodiversity loss with substantial environmental and economic impacts on invaded communities. While the potential economic cost for almost 90% of the alien species found in Europe is still unknown, the European Commission (2008) estimated the economic impact of alien species in Europe to be close to €10 billion annually, giving urgency to the scientific community to better understand which species are likely to have large impacts on the novel communities to which they are introduced. In this framework, urban areas usually contain the greatest proportion of alien plants; on one hand, cities act as focal point for the broad-scale introduction (both intentional and unintentional) of new species (Pyšek, 1998; Wittig, 2004; Chytrý et al., 2005, 2008). On the other hand, the ‘urban heat-island effect’ provides distinctive environmental conditions that have allowed many alien species with higher temperature requirements and tolerance for arid environments to become Department of Plant Biology, University of Rome ‘‘La Sapienza’’, Piazzale Aldo Moro 5, 00185 Rome, Italy, National Botanic Garden of Belgium, Domein van Bouchout, 1860 Meise, Belgium, Laboratory of Plant Biology and Nature Management (APNA), Department of Biology, Faculteit Wetenschappen en Bio-ingenieurswetenschappen, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium, Laboratory of Complexity and Dynamics of Tropical Systems, CP 169, Département de Biologie des Organismes, Faculté des Sciences, Université libre de Bruxelles, Avenue F.D. Roosevelt 50, 1050 Brussels, Belgium, IASMA Research and Innovation Centre, Fondazione Edmund Mach, Environment and Natural Resources Area, Via E. Mach 1, 38010 S. Michele all’Adige, TN, Italy