Biology Reference
In-Depth Information
Because control actions taken against invasive pests can themselves have potentially
broad ecological impacts, due deliberation and care must be exercised to ensure
that such impacts are minimized or avoided. For example, unintended damage to
native wildlife may occur because some natives may now use invasive species -
such as using invasive plants for food or refugia - for lack of other options. Such
conflicts arise as a direct result of the tremendous degree to which human activi-
ties have modified the world. This is not to say that large control operations
against invasive species should be abjured, merely that they need to be thought-
fully planned and implemented so as to avoid creating additional problems for the
biotas or resources they are intended to protect.
Long-term management and control of ineradicable pests thus can be a complex
undertaking with diverse ramifications. Typically, benefits are believed to outweigh
costs where the goals of the control effort are clearly defined and lead to protection
of high-value resources, e.g., biodiversity or agricultural sites of high value. These
issues and the complexities involved are treated in greater depth by Wittenberg and
Cock (2001) and Courchamp et al. (2003), which should be consulted for more
thorough treatments of management topics. De Wit et al. (2002) provide an excel-
lent example of how to conduct an explicit cost/benefit analysis identifying best
control options for a widespread invasive. It is worth emphasizing, however, that
although range-wide eradication of widespread invasive pests is typically unachievable,
discrete geographical units, such as islands, may be liable to removal of invasives
and sustained as pest-free. For these instances, considerable progress has been
made in developing tactical methods and operational strategies for the eradication
of invasive pests from increasingly large areas. A recent sampling of such work can
be found in Veitch and Clout (2002), and comprehensive summaries of operations
against certain pests (Nogales et al., 2004; K. Campbell and Donlan, 2005; Howald
et al., 2007) or for certain geographic areas (B.D. Bell, 2002; Burbridge and Morris,
2002; Ebbert and Byrd, 2002; Merton et al., 2002; Tershy et al., 2002; Clout and
Russell, 2006) are also available. With respect to reptiles and amphibians in partic-
ular, however, tactical control methods are poorly developed, although mechanical,
chemical, and habitat-modification tools have all been attempted. These examples
will be discussed in Chapter 4.
History of Research on Alien Reptiles and Amphibians
Although impacts from some alien invasions have been recognized since the late
1800s (cf. Elton, 1958), it wasn't until rather recently that problems associated
with reptile and amphibian invasions began to be noticed or documented. Hence,
while Ebenhard (1988) could devote a 107-page monograph to the ecological
impacts of alien birds and mammals, mention of reptiles and amphibians is absent
from Elton (1958) and Mooney and Drake (1986). Similarly, the cane toad (
Bufo
marinus
) is the only herpetological species to appear in Groves and Burdon
(1986), and it merits only passing mention. This delayed concern for alien reptiles
