Biology Reference
In-Depth Information
that serve as vectors for heartwater disease (U.S. Code of Federal Regulations: Title
9 CFR Sections 74.1, 93.701); and public health regulations prohibit the importation
of turtles smaller than four inches, or their eggs (Title 42 CFR Section 71.52-53).
Each of these restrictions was imposed in reaction to widespread publicity of one-
time newly identified, specific threats: extinction of birds on Guam caused by
brown treesnakes, potential for importation of heartwater disease via tick-infested
tortoises, and
Salmonella
transfer between young turtles and children, respectively.
In a somewhat more proactive vein, in 2000, the United States Fish and Wildlife
Service solicited risk analyses for a variety of species it identified as potentially
invasive. Taxa were apparently chosen for study based primarily on high commer-
cial trade volume, and two of these studies concerned reptiles or amphibians. Rolan
(2003) assessed potential risk of 24 amphibians; Reed (2005) assessed the risk of
large boas and pythons and made a series of recommendations to reduce risk from
these imports. It is unclear that either report has led to consideration of any regula-
tory action by the United States Government, but the Fish and Wildlife Service for
the past five years has been considering banning the importation of all species of
Boiga
, and that same agency has recently proposed banning the importation of
some large constrictors. Other than this one-time effort, coordinated, proactive
assessment of invasion risk posed by other species of reptiles and amphibians has
not been pursued by the United States.
A similarly taxonomically limited, reactive approach led the European Union in
1997 to ban importation of
Trachemys scripta
and
Rana catesbeiana
(Detaint and
Coïc, 2006; Dupré et al., 2006; Scalera, 2007b), although possession of these spe-
cies is not banned, and both may still be traded among European Union member
states (Scalera, 2004). This import prohibition followed widespread naturalization
of the two species in climatically acceptable regions of the continent, which gener-
ated concern about the potential risks of these notorious invaders to native wildlife.
Although some animals continue to be smuggled into some European Union states,
arrests aiming to curtail this activity have occasionally been made, and tens of
thousands of animals have been seized (Fiore and Avanzo, 2002; Dupré et al.,
2006). This ban was followed in 2005 by an additional ban on
Chrysemys picta
,
whose importation volume increased dramatically with the curtailment of trade in
T. scripta
(Scalera, 2007b). However, as Scalera (2007b) pointed out, a coordinated
effort in the European Union to address invasive species of any kind has not been
made, so actions currently are restricted to isolated activities by member states.
Genovesi and Scalera (2007) have proposed the adoption by the European Union
of a coordinated system of lists covering taxa approved, prohibited, or requiring
further study for importation. Doing so would make prevention programs for alien
herpetofauna in the European Union far more proactive and effective than the cur-
rent approach and move it considerably beyond the reactive paradigm adopted by
the United States. National prohibitions by European Union member states against
alien species are as hit-or-miss as those of the United States, and few of these
include mention of reptiles or amphibians (de Groot and Gerrits, 2002).
Guam too has responded to the threat posed by a single herpetological species -
in this case the coqui,
Eleutherodactylus coqui
. As noted in the preceding chapter,
