I compared lizard perch use between 4 treatment plots (4"x4" posts added as artificial perches) and 4 control plots. Plots were unenclosed 5 x 5 m vegetated areas inhabited by naturally occurring resident lizards (brown anoles, Anolis sagrei). Plots were established on Staniel Cay (Exuma Chain, Bahamas) in Sept 2007, and behavioral observations continued through May 2008. The addition of artificial perches resulted in the availability of novel resources for this site, as posts were much wider and taller than the naturally occurring vegetation. I developed a resampling technique to estimate the expected niche breadth in each plot given sample size, perch availability, and the number of resource types available.
Results/Conclusions
On average, lizards in treatment plots used wider perches than lizards in control plots, with treatment males using perches roughly twice as wide as treatment females. Treatment females became more generalized relative to control females, while treatment males became more specialized. This pattern is explained by shifts in the types of resources used: treatment males largely shifted onto wider perches, while treatment females expanded their resource use across niche space. These sex-specific responses are likely explained by brown anole social structure: males defend territories that contain several females. The artificial perches were much taller than the natural vegetation, and therefore may have facilitated vigilance and transmission of visual displays. Alternatively, the artificial perches may be more important for thermoregulation in males as they are much larger. Overall, the observed niche breadth flexibility and rapid behavioral shift to utilizing novel resources may be related to this species’ success as an invader of both disturbed and non-native areas.
