Resource niche partitioning and overlap among native and non-native lizards in an urban environment

Non-native species must overcome a number of abiotic and biotic filters to successfully establish and spread into novel ecosystems. Their establishment and spread depend on the ability to acquire resources while avoiding or outcompeting native species. The Mediterranean House Gecko ( Hemidactylus turcicus Linnaeus, 1758) has been widely introduced into urban areas across tropical and temperate regions, yet studies documenting their resource use relative to native lizard species are still lacking. We examined patterns of resource use between Hemidactylus turcicus and a recipient lizard assemblage comprised of Green Anole ( Anolis carolinensis Voigt, 1832), Little Brown Skink ( Scincella lateralis Say, 1823), and Five-lined Skink ( Plestiodon fasciatus Linnaeus, 1758) in an urban ecosystem of eastern Texas. We used functional traits to investigate resource partitioning between Hemidactylus turcicus and native lizards regarding habitat, diet, and isotopic niche dimensions. Differences in resource use between Hemidactylus turcicus and native lizards were observed, as they utilized a greater array of arboreal perch types at lower temperatures, had generalist diet, and occupied a broader isotopic niche space compared to the native lizards. Overall, Hemidactylus turcicus appears a functionally unique species capable of exploiting novel resources along multiple niche axes possibly facilitating their establishment and spread into urban ecosystems.