Exotic Amphibians and Reptiles

Exotic Amphibians and Reptiles (continued from page 2)

project is currently underway that measures flight distances for both the Indo-Pacific gecko and wood slave at JULBSB. Differential flight distances could presumably affect predator avoidance and foraging efficiency which in turn could explain species turnover rates. For example, a species quick to flee a disturbance and reluctant to return could be at a disadvantage in its ability to forage efficiently. Conversely, a slow response time to predators could doom the individual and consequently the colony from differential predator pressure by such building-dwellers as the Cuban treefrog (Meshaka 2000). Such has been the case of two native hylid treefrogs, which are nutritious and naïve prey for Cuban treefrogs of many body sizes, and are negatively affected by the depredations of this species (Meshaka 2001). Could the same be true of Hemidactylus species that are

be removed or turned off during turtle breeding season, thereby inhibiting exotic geckos and the Cuban treefrog while at the same time improving conditions for successful sea turtle nesting.

As control measures, we also note that the number of refuges are known to affect Cuban treefrog abundance (Meshaka 2001) and thus could be controlled around buildings with the same practical goal of reducing habitat quality for these exotic building syntopes that rely on refuges as do exotic geckos, or, as in the case of the Cuban treefrog, are limited by them.

Public lands of South Florida across the spectrum between the

slower to respond to a predator, thereby accelerating their demise or suppressing their success? We have yet to determine if the wood slave is differentially susceptible to the depredations of the Cuban treefrog, or for that matter to other potential predators, such as the Eastern screech owl (Otus asio).

The results of another “Parknership” program speak to the benefits of exotic species as predators rather than prey, whereby an exotic prey species trophically paves the way, as it were, for the success of its exotic predator. For example, in a study on the exotic Northern curlytail lizard (Leiocephalus carinatus armouri), Smith and Engeman (2004) corroborated the dearth of its prey, the exotic brown

completely pristine natural area and the urban ecosystem are vulnerable to various levels of exotic species colonization. The “Parknership” Research Program provides an opportunity to connect vital research pertaining to colonization dynamics with management goals of public land protection. Repetitions of surveys employing a uniform method in varied locations and habitats are beginning to reveal colonization patterns and subsequent effects, and these very sites then serve as reference points to future on-site surveys. Only when exotic species colonization patterns such as these mentioned above are understood spatially and temporally is it possible to develop effective policy measures to mitigate current colonization events, or to prevent or impede future invasions of public

anole (Anolis sagrei) in colonized areas, a finding likewise observed in other studies of the Northern curlytail lizard first noted by Callahan (1982), subsequently noted by Meshaka and colleagues (2004), and one that led Meshaka and colleagues (2005b) to suggest that “Quite possibly, dense populations of A. sagrei could provide geographically expanding populations of L. c. armouri with a nutritious prey base to its advantage…”.

This very phenomenon was present in the case of the Cuban treefrog’s colonization through the depredations of both the green treefrog and squirrel treefrog, whereby this occasionally abundant resource is converted into growth and egg production and secondarily is marginalized or eliminated as a potential competitor (Meshaka 2001). Could a version of this phenomenon be at work with exotic geckos? In urban parks, where potential competitors are rare if present and the Cuban treefrog has yet to arrive or is likewise at some disadvantage (e.g., climate, hydrology), we wonder if the underexploited invertebrate prey base around building lights can provide these geckos with a distinct colonizing advantage with respect to presumed reduced foraging time and increased nutrition for growth and reproduction just as underexploited hylid prey benefit the Cuban treefrog. Indeed, it is the surplus geckos, or for that matter, any colonizing species—native or exotic—of a productive building that would ultimately increase the likelihood of new natural and human-mediated dispersal events. This notion has precedent in that poorly lighted buildings supported fewer Cuban treefrogs than did better lighted counterparts in ENP (Meshaka 2001). Perhaps, for buildings that must be lighted, installation of yellow bug lights, which do not attract invertebrates, could be experimentally implemented park-wide as a testable control measure to decrease habitat quality for these species. Ideally lights can

lands, such as Florida State Parks. We have found that the “Parknership” model proffered here is a productive and practical approach to realize this goal and generally applicable on many protected areas both private and public and both individually and park-wide.

Acknowledgments These studies were part of the honors thesis research in biology of Kimber L. Kingsland at Florida Atlantic University, Harriet L. Wilkes Honors College, and a Florida Park Service ”Parknership” Research Program internship for Heather L. Cress at John U. Lloyd Beach State Park.▪

*Author to whom correspondence should be addressed:

¹John U. Lloyd Beach State Park, 6503 North Ocean Drive, Dania Beach, Florida, 33004, USA.

²Florida Atlantic University, Wilkes Honors College, 5353 Parkside Drive, Jupiter, Florida, 33458, USA.

³Florida Park Service, 13798 S.E. Federal Highway, Hobe Sound, Florida, 33455, USA.

⁴The State Museum of Pennsylvania, 300 North Street, Harrisburg, Pennsylvania, 17120-0024, USA.

Literature Cited (Removed for space; please contact author for citations.)

A Steward’s Circle Article

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