Environmental Engineering Reference
In-Depth Information
14
and response tools
Richard F. Piola, Chris M. Denny, Barrie M. Forrest,
and Michael D. Taylor
Marine alien invasive species (AIS) are now considered a major threat to the diver-
sity and health of coastal regions worldwide (Carlton and Geller 1993; Vitousek
et al
. 1997; Cohen and Carlton 1998; Mack
et al
. 2000), overshadowing even the
threat from the excess of other human activities whose impacts have traditionally
received considerably greater attention (e.g. waste discharge, habitat reclamation).
Human-mediated transport vectors such as shipping, aquaculture, and fi shing act
as a continuous source for inoculation of AIS into new regions, with the rate of
species movements between different regions at unprecedented levels (Mack
et al
.
2000). Changing environmental conditions have also allowed for the successful
invasion of new regions by species that had previously failed to establish (Dukes
and Mooney 1999; Harris and Tyrrell 2001; Diederich
et al
. 2005; Grosholz 2005;
Nehls
et al
. 2006). Although positive commercial and even ecological benefi ts of
some AIS are recognized (e.g. Galil 2000; Sinner
et al
. 2000; Hayes and Sliwa
2003; Wonhom
et al
. 2005), the primary focus of scientists, regulatory agencies,
and other stakeholders is on invasive species as a threat to ecological and socio-
economic values (e.g. Hewitt
et al
. 2004). In the US and Canada alone, the pro-
jected economic impact from a few of the more notorious marine invasive species
has been estimated to be in the order of approximately $US 2 billion per year
(Pimentel
et al
. 2000; Colautti
et al
. 2006).
h e biological invasion process can be broken down into a number of stages:
1)
Entrainment of an organism by a human transport vector (e.g. maritime
vessel) and the transport of the organism beyond its natural range (via vector
movement).
The establishment of a viable population within a new location/region.
2)
3)
The spread of the organism away from its initial area of introduction
(Fig. 14.1a).
