Biology Reference
In-Depth Information
amphibians and has provided an impetus for research on additional species. But this
awareness and action still lag well behind that accorded other taxa. Most of this
increased activity has merely recorded new introductions, documented range
expansions, or provided descriptive autecological information on some populations
of naturalized reptiles and amphibians. A growing number of studies, however, has
documented additional negative impacts to native biota or to human activities
resulting from a variety of invasive herpetofauna (see Chapter 3). Scientists occa-
sionally model predicted range expansions of select taxa based on matching
climatic parameters between native and invaded ranges (e.g., van Beurden, 1981;
Sutherst et al., 1996; Adrados, 2002; Ficetola et al., 2007a; Urban et al., 2007).
There have been regional summaries of herpetological introductions for a few areas
(e.g., King and Krakauer, 1966; Bury and Luckenbach, 1976; Smith and Kohler,
1978; L.D. Wilson and Porras, 1983; McCoid, 1995a, 1999; Ota, 1999; Meshaka
et al., 2004a; Ota et al., 2004a), and a recent topic summarizes some of what is
known about particular established species of alien reptiles and amphibians
(C. Lever, 2003). A brief overview of some common pathways and impacts of alien
herpetofauna has recently appeared (Scalera, 2007a) but is focused on those species
associated with aquatic habitats. There have been, however, virtually no studies that
test explicit scientific hypotheses about herpetological invasions - most work to
date has been simply descriptive.
Little knowledge, too, has been added that would be practically useful for stem-
ming the rising tide of naturalized populations of alien reptiles and amphibians. For
example, a couple of brief assessments of introduction pathways for the alien her-
petofauna of Florida exist (L.D. Wilson and Porras, 1983; Butterfield et al., 1997),
but only one prior study (Kraus, 2003c) has attempted a broad-scale quantitative
assessment of this topic, and that was merely an early precursor to the expanded
analysis of the next chapter. As for damage from invasive herpetofauna, no rigorous
summary of ecological or social impacts from alien reptiles and amphibians has
previously been published. Some useful information on impacts may be gleaned
from C. Lever (2003), but that topic mixes evidence and speculation with little dis-
tinction, and there has been much untested speculation about impacts promulgated
in the herpetological literature. If informed decisions are to be made on designing
prevention systems for alien reptiles and amphibians we need better data on both
introduction pathways and ecological, economic, and social impacts. Attempts to
predict invasion success have just begun to be investigated for reptiles and amphibians.
Rolan (2003) provided an assessment of risk to native amphibians of the United
States posed by 24 species of alien amphibians, and Reed (2005) did likewise for
an assortment of pythons and boids. Bomford et al. (2005, in press) provided
evidence that history of prior establishment, climate match, and phylogenetic relat-
edness were correlated with establishment success for alien reptiles and amphibi-
ans. Rodda and Tyrrell (in press) assessed likely ecological attributes that would
favor urban, pet-trade, and invasive herpetofauna, and they concluded that overlap
in attributes between these three sets is high. But testing those predictions with
empirical data remains to be done. Clearly, efforts to obtain the information necessary
to predict invasiveness of alien herpetofauna have just begun.
