Biology Reference
In-Depth Information
Fig. 2.11
Relative importance of pathways of herpetofaunal introduction as measured by num-
bers of species successfully established
refers to the trade in live plants, usually for ornamental purposes, although transport
of food trees for tropical gardening has also been involved. Clearly, this pathway is
a subset of the cargo pathway but has proven of sufficient importance in its own
right and presents a qualitatively different set of transport conditions to warrant
separate examination. “Pet trade” is self explanatory and includes deliberate
releases and unintentional escapes of pet animals, whether the responsible parties
were private individuals, retail dealers, or wholesale traders. I generally view the
pet-trade pathway as one of intentional introduction even when a particular release
may not have been. This is both because the importation was intentional and
because the consequence of irresponsible ownership of animals will be the frequent
and predictable escape of the deliberately imported pets. “Intentional” as used as a
separate category in the figures is somewhat of a catch-all. It refers to what is
clearly a deliberate introduction by an individual, but it lacks the precise knowledge
of motive that is characteristic of the other deliberate pathways. Most often, intro-
duction for perceived amenity or aesthetic reasons may be vaguely inferred from
reports citing this pathway, and there is clearly a close relationship with the motives
underlying the pet-trade pathway; however, the precise psychological motives
behind the release cannot usually be perceived with any assurance. This is the least
well-defined and least satisfying of the pathway categories, but these deliberate
releases have nonetheless been an important means of herpetological introductions.
Because choice of terminology could be confusing for this pathway vis a vis the
sum of all those pathways having an intentional motive (e.g., food, biocontrol, pet
trade), when I refer to this specific pathway, I will always enclose it in quotes.
Of these six pathways, the greatest volume of introductions has been via the pet-
trade and cargo pathways, with “intentional” introductions trailing those two but
still of considerable importance (Figs. 2.8-2.11). The remaining three pathways
have also been important but consistently less so in overall numbers.
