Considering urban uses at a fine spatial resolution to understand the distribution of invasive plant species in cities

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Cities are heterogeneous landscapes, composed of different urban uses with diverse histories. A thorough description of these urban landscapes is required to understand ecological patterns, particularly concerning high-stakes species such as invasive alien plants (IAP) which are abundant in cities. We assessed the effects of urban uses and linear structural elements on the distributions of seven IAP in a medium-sized French city (Blois). We examined how the relative contributions of these variables vary between three spatial scales of analysis (100 m, 200 m and 400 m) and three urban classifications. We characterized the use and age of urban neighborhoods through three classifications with different levels of details and described road and rail networks of Blois. We analyzed their effects on the distribution of seven invasive plants recorded throughout the whole city using GLM models. Urban use was the most significant variable in explaining IAP distribution. This variable was especially important at the finest spatial scale which allowed a detailed urban classification. Individual residential neighborhoods of different ages explained the distribution of Buddleja davidii, Berberis aquifolium and Acer negundo, whereas industrial areas explained Ailanthus altissima distribution. The effects of linear structural elements were lower and differed between species. We show that combining fine-scale spatial analyses with detailed characterization of urban use diversity is critical to understanding ecological patterns at the city scale. Investigating planting choices and dispersal process of IAP could complete our results. Urban descriptions based on explicit urban forms could also contribute to understanding species distribution in cities.