Biology Reference
In-Depth Information
has confirmed that a few populations (now all extinct) were native and unrelated to
the lineages from which introduced animals were descended (Gleed-Owen, 2000;
Zeisset and Beebee, 2001; Wycherly et al., 2002; Beebee et al., 2005; Snell et al.,
2005). Without the introductions, the species would likely have been recognized as
a native element of the British fauna sooner, perhaps in time to prevent its extirpa-
tion there. Similar problems hold in the case of
Iguana iguana
and
I. delicatissima
.
The former is widespread across tropical America and parts of the Lesser Antilles;
the latter is endemic to some of the Lesser Antilles. The native range of
I. iguana
in the Antilles is uncertain, but some populations are certainly introduced (Lazell,
1973; Lescure, 1983; Breuil, 2002). On Guadeloupe and the adjacent Îles des
Saintes, the two species have been hybridizing, with
I. delicatissima
populations
disappearing in the process (Day and Thorpe, 1996; Day et al., 2000; Breuil, 2000a, b,
2002). Clearer knowledge of the native range of
I. iguana
might have generated
concern for a possible introduction and instigated mitigative measures to avert this
loss, but such data were and remain lacking.
Other scientific losses occasioned by herpetological introductions are widely
recognized, even as they remain largely undiscussed. Primary among these is that
the original ecological dynamics in unique regions or habitats heavily invaded by
alien reptiles and amphibians are likely to never be understood. The cascade of
effects attendant upon introduction of
Boiga irregularis
to Guam (Fritts and Rodda,
1998) well illustrates the loss of understanding of original ecological dynamics that
can occur subsequent to an invasion. Similar epistemological effects certainly apply
to regions already heavily invaded by alien reptiles and amphibians, such as south-
ern Florida, Hawaii, and Okinawa, and they likely occur even in areas having only
a single significant herpetological introduction, such as the Ogasawara Islands. It is
reasonable to expect this loss of scientific knowledge to be common even though it
typically goes unremarked. In a broader sense, because much of ecology involves
understanding spatial and temporal scales of disturbance regimes and the ecological
patterns thereby derived, when an area becomes overwhelmed by alien introduc-
tions, the ecological dynamics and patterns due to other disturbance regimes are
liable to be masked and less accessible to understanding. These problems, of
course, are compounded in places like Hawaii or the Mascarene Islands where mas-
sive introduction regimes are superimposed upon large numbers of native-species
extinctions.
One final epistemological loss extends far beyond the realm of science and its
application. It is widely noted that modern humans are becoming increasingly
alienated from nature, concomitant with increased concentration of human popula-
tions in urban areas far from any sustained contact with nature. This alienation can
make it difficult to gain public acceptance for biologically sensible conservation-
management decisions because large segments of society are cognitively divorced
from the biological realities upon which their lives are based. One way in which
this problem is worsened is by introduction of alien species, which, because of their
frequent abundance, will often be unthinkingly accepted by most people as “normal”,
implicitly interpreted to mean “native”. This has practical implications for native
plants and wildlife by making needed control of invasive aliens harder for an
