Tag Archives: abundance

JMIH 2017: Removal of Curly-tailed Lizards Increases Survival of Urban Brown Anoles

CRodriguez_JMIH2017

Interspecific Interactions Between Two Species of Invasive Lizards in an Urban Environment; Camila Rodriguez-Barbosa and Steve Johnson

An extensive body of work has addressed the eco-evolutionary impacts of the Northern Curly-tailed Lizard (Leiocephalus carinatus) on Brown Anoles (Anolis sagrei) (much of it receiving coverage right here, here, and here on Anole Annals!). These species co-occur not only on many Caribbean islands where much of this research has taken place, but also within the urban matrix of southern Florida, where both species are introduced.

Camila Rodriguez-Barbosa and Steve Johnson investigated the impacts of curlies on brown anoles in shopping centers in southern Florida where both species were plentiful. Camila first collected baseline data on anole and curly populations at eight sites before embarking on a quest to eliminate curlies from four of her sites. Over the next four months, she removed over 300 (!) curlies from these sites, many of which had brown anole remains in their stomachs.

She found that this removal had serious consequences for brown anoles. Compared to anoles from shopping centers where curlies were unchanged, A. sagrei at removal sites experienced higher survival and consequently greater abundances. These anoles also shifted to lower perches once curlies were removed, mirroring results from previous work which show that the introduction of curlies leads to brown anoles occupying higher perches to escape this dangerous predator. Camila’s work suggests that brown anole/curly-tailed lizard interactions may be similar even in very different habitats and provides a fascinating look at lizard life (and death) in the urban sprawl of southern Florida.

Variation in Population Density in Anolis Aeneus on Union Island

Anolis aeneus. Photo from http://www.kingsnake.com/westindian/anolisaeneus5.JPG.

Surprisingly few studies have examined how anole population density varies geographically, much less trying to explain why. In a recent study, McTaggart and colleagues surveyed herpetological abundance across Union Island (8.4 km2) in the Grenadines (near Grenada). Anolis aeneus was by far the most abundant herp on the island and was found almost everywhere. However, its abundance did vary from 0 to 62 individuals seen in visual encounters performed during the course of a morning and an afternoon. The sites lacking A. aeneus were a mangrove and a transect from a scrubby coastal hillock to a beach; overall, anole abundance was strongly correlated with vegetational complexity (categorized based on the number and variety of trees, height and connectedness of the canopy, and extent of human disturbance), perhaps not surprising for an arboreal lizard often found high in trees.