Marc W. Cadotte
University of Toronto-Scarborough, 1265 Military Trail, Toronto, ON, M1C1A4, Canada
Urban environments are often seen as unique or degraded habitats that present both hardships for some sensitive species and provide opportunities for others. How non-indigenous species (NIS) respond to urban environments is not well understood. I ask a simple question: do NIS benefit from urbanization? I answer this based on a literature review and meta-analysis where I show that the available evidence supports the proposition that NIS benefit from urbanization, with NIS obtaining higher abundances and greater diversity in more urbanized habitats. The NIS that benefit from urbanization for establishment can then go on to spread and impact native habitats. One approach to understanding NIS success and impact is to assess how their functional traits influence their spread and impact. I will use the example of the invasive plant Vincetoxicum rossicum (Kleopow) Borhidi which has established itself as one of the dominant urban invaders in the northeastern United States and southeastern Canada. To examine the mechanisms underpinning the success and impacts of V. rossicum, I will discuss trait-based insights, using trait data for seven different functional traits (i.e. height, stem width, specific leaf area, leaf percent nitrogen and leaf percent carbon) from 500 1×1 m plots across a gradient of invasion in the Rouge National Urban Park located in suburban Toronto, Canada. V. rossicum occupies unique niche space, possessing trait combinations not found in the native flora, and its impact comes from its ability to alter the niche space for other species.