Extensive human-mediated translocation of species from their native ranges to alien environments is a trademark of the Anthropocene. Particularly in island ecosystems, established non-native species often have highly detrimental impacts on native taxa and thus the study of the drivers mediating the establishment and expansion of introduced species in areas outside their native range is crucial to delineate timely and effective mitigation measures. Species distribution models (SDMs) are widely used in invasion biology and offer great potential for the assessment of invasion risk and the identification of areas likely to be colonized by expanding alien species. Within reptiles, Gekkonidae is the second family with most introductions globally, a reflection of the group's capacity to survive long distance dispersal events. The temperate Moorish gecko (Tarentola mauritanica) is native to the Mediterranean basin but has established alien populations in multiple localities throughout the word. It was first reported in the subtropical island of Madeira in 1993 and over the last three decades has colonized a substantial section of the island's south coast. Here, we use Madeira Island as a case study to investigate the interplay between bioclimatic and local scale variables on the occurrence of T. mauritanica in areas outside its native range. We found that the species favors areas with high temperatures during the coldest month, low mean temperatures during the wettest quarter, low annual values of precipitation, and high precipitation during the driest quarter. This translates to an obvious preference for areas with more Mediterranean-like climates which in Madeira are primarily located in the south and south-eastern sections of the island. Additionally, our models predicted that some areas of the northern coast of Madeira offer suitable conditions for the gecko, although no observations have yet been recorded. Tarentola mauritanica is expanding its range in Madeira and has already colonized the nearby island of Porto Santo. It is paramount that more research is devoted to understanding the impact of this alien gecko on the island's native species and ecosystems, and in particular on its endemic-rich arthropod communities.
