I’m not like everybody else: urbanization factors shaping spatial distribution of native and invasive ants are species-specific
Résumé
Urbanization is a major global change inducing complex and multiple modifications of landscapes and eco- systems. The spatial distributions of organisms experiencing these modifications will likely shift specifically, depending on each species’ response to each environmental modification induced by urbanization. We sampled two ant genera (Lasius and Tetramorium) at 1248 locations along an urbani- zation gradient in Lyon, France and used high resolution spa- tial layers for 18 spatial (e.g., open habitat fragmentation, bio- climatic data and surface temperatures) and temporal (e.g., comparison of Normalized Difference Vegetation Index be- tween 1986 and 2015) environmental variables associated with urbanization. Coupling two different analytical methods (Outlying Mean Index and Boosted Regression Trees), we showed that each species’ distribution was influenced by its own combination of environmental factors. Two morphologically cryptic Tetramorium species (T. sp.E and T. sp.U2) were both highly abundant but with opposite responses to urbanization: while T. sp.E was favored by urbanized habitat, T. sp.U2 avoided urbanized areas. Among Lasius species, we detected 63 occurrences of the invasive ant Lasius neglectus, the distribution of which was favored only by embankments along roads. We found that, even at this reduced spatial scale, climatic effects influenced most species and interacted with urbanization factors.