Biology Reference
In-Depth Information
Chapter 5
Implications for Policy and Research
There has been no prior synthesis of pathway information, impacts, or human
management of introductions for alien reptiles and amphibians. Yet those data are
of critical importance for informing future management and research decisions
with respect to these animals. They are especially important inasmuch as the mod-
ern flood of invasive species represents one of our greatest conservation challenges.
So what general patterns and conclusions emerge from the data provided in the
previous chapters?
We have seen that a wide array of pathways has been involved in herpetological
introductions, but that six of these have been dominant, even though their impor-
tance varies taxonomically, temporally, and geographically. In addition to these,
four minor pathways contributed lesser numbers of introductions to the total. We
have seen that several of these major and minor pathways revolve around similar,
unifying themes: an aesthetic nexus that promotes the keeping of animals and their
frequent escape, release, or introduction via private owners, wholesalers, retailers,
exhibitors, or zoo personnel, and a trade-goods nexus that transports animals in
cargo or vehicles as unintentional hitch-hikers in the course of regional or interna-
tional trade activities. The patterns of taxonomic, temporal, and geographic varia-
tion seen in pathway importance allow scope to investigate whether ecological and
economic parameters might serve to predict variation in naturalization and invasion
success. Although that work is not begun in the present work, one study demon-
strates the importance of climate, propagule pressure, and phylogenetic propinquity
in predicting establishment success among alien reptiles and amphibians (Bomford
et al., 2005, in press). Examination of a wider array of ecological attributes seems
likely to improve predictive success in this regard, which would be useful for
screening proposed deliberate introductions for likely invasiveness.
We have seen that islands are more prone to herpetological naturalization than
are continents. Although not directly investigated here, it is possible that this pattern
reflects the easier invasibility of these relatively depauperate areas.
It is also clear that a wide variety of damaging impacts has resulted from
herpetological invasions, even though only a relative handful of naturalized popula-
tions has been examined in any ecological or economical detail. It is beyond con-
tention that herpetological invasions can result in tremendous damage to other
native fauna, broader ecosystem values, human health, and human economies.
