Meeting Abstract
Populations of Anolis lizards are successfully established in urban environments, which differ in structural aspects, among others, from natural habitats. However, urban habitats are diverse, comprising a complex matrix of natural and artificial substrates. We ask how often lizards use artificial substrates in urban areas and whether performance differs between smooth (artificial) and rough (natural) surfaces. We recorded perch use frequencies (natural vs. artificial) of Anolis cristatellus and Anolis stratulus in natural and human-disturbed (urban) sites on Guana Island in the British Virgin Islands and determined substrate roughness on a scale from 1 to 5. Lizards were found more frequently on artificial substrates than on natural ones (i.e. trunks and branches) at urban sites. Substrates in urban habitats were significantly smoother than those in natural habitats. We then tested experimentally, whether performance (i.e., maximum velocity) differed across substrates by running lizards on tracks varying in roughness and incline. Lizards sprinted faster on inclined and rough vertical tracks compared to smooth vertical tracks. This decrease in performance was particularly severe for male A. cristatellus because they are much heavier than female A. cristatellus or either sex of A. stratulus. Our results suggest that even though performance decreases on artificial substrates, lizards still frequently use these substrates in urban areas. Therefore, other aspects of the urban environment such as better escape opportunities or more efficient foraging may influence this choice.
