Methods Three Florida east coast study sites were visited for approximately ten week periods. The first was Savannas Preserve State Park (SPSP), a 2,115-ha preserve that is surrounded by rural areas and suburbs. The second site was John U. Lloyd Beach State Park (JULBSP), a 126-ha park that is situated in an urban/industrial area. The third site was Florida Atlantic University (FAU), John D. MacArthur Campus, in the middle of a suburban area. The three studies applied a

the relative abundances of exotic geckos. For example, because it was the building with the smallest perimeter, “Gas Station” experienced the quickest species turnover from Indo-Pacific geckos to wood slaves at ENP (Meshaka, 2000). By 1998 there were no Indo-Pacific geckos, and the wood slaves had proliferated beyond the Indo-Pacific gecko numbers at the start of the 1992 study (Meshaka 2000).

standard protocol for assessing the community structure of buildingdwelling nocturnal species (Meshaka 2000, 2001; Meshaka et al. 2005a, 2006). Sites were surveyed once weekly, under a less than three quarter moon phase, walking once around each structure. With a flashlight, we counted all individual herpetofauna seen on one pass around each building. We recorded the initial and final time of each building search and the ambient temperature and relative

Building color can also have an effect on the species turnover rate. For example, at one site at FAU, because the building was white, the building color closely matched lighter-hued Indo-Pacific geckos, and this camouflage is thought to have slowed its faunal turnover (Meshaka et al. 2006). Conversely, on another building, the shade house, a very dark colored wooden structure with black landscape fabric at JULBSP,

humidity. We also noted permanent features of the buildings that could explain findings associated with our counts, such as building size (perimeter), building age, building color and structure (wood, concrete block, etc.), and number of lights.

Results and Discussion Relative abundances of the Indo-Pacific gecko (Figure 2) and the wood slave (Figures 1 and 3), the only two hemidactyline geckos observed, indicate that the one-way replacement process involving these two competing, exotic ecological analogs in Florida was occurring at all survey sites. Our findings revealed that across the different locations, all with varied habitat conditions, colonization through its successional stages produced similar outcomes—the wood slave rapidly replaced the Indo-Pacific gecko quickly and with many more individuals. Ratios of the wood slave to Indo-Pacific gecko also reflect the age of wood slave introduction at a site. The larger the gap between the relative abundances of the Indo-Pacific gecko and the wood slave (with a higher number of wood slaves), the longer the wood slave has occupied the site and displaced the Indo-Pacific geckos. Thus, the ratios of the geckos among buildings within a site, such as a park, and among various sites quantify the rate at which colonization and replacement are occurring.

The physical attributes of the building affect

Predators can also affect the colonization dynamics of the Indo-Pacific gecko and wood slave. For example, predation pressure by the Cuban treefrog on Indo-Pacific gecko-only buildings in south-central Florida resulted in gecko populations comprised of larger adults and fewer juveniles than on Indo-Pacific gecko-only buildings that lacked this predator (Meshaka et al. 2004). On buildings with both gecko species and the Cuban treefrog, the ratio of Indo-Pacific gecko to wood slave was in greater equilibrium, and the turnover process seems to have been slowed or stalled. Both at ENP and Savannas, the Cuban treefrog maintained greater equilibrium in the gecko ratios on select buildings (Meshaka 2000, Meshaka et al. 2005a). Thus, predator-prey interactions differentially affect buildingdwelling populations of the Indo-Pacific gecko depending on the presence or absence of a congeneric species. To further understand mechanisms for species replacement in this gecko pair, a “Parknership”