Environmental Engineering Reference
In-Depth Information
a relatively low national priority. h at is, the short-term imperatives of human
issues are likely to have higher priority than establishing quarantine measures
despite the potential longer-term consequences of not doing so.
Apart from the biological characteristics of invasive organisms, many other factors
need to be considered during the implementation of quarantine measures. In par-
ticular are the pathways via which organisms can enter new areas. There are three
broad categories of pathways of introduction:
1)
Species that spread naturally either passively by water or wind, including
extreme events such as cyclones, or actively fl ying, crawling, or swimming.
Species that are accidentally introduced hitch-hiking or vectored on/by
2)
something for example,: during trade; movement of material during emer-
gency relief or confl icts; traditional movement of people; movement of
plants, animals, or soil; scientifi c materials; traveller's personal effects; move-
ment of contaminated agricultural, military, or industrial equipment; ships,
including ballast water.
Species that are deliberately introduced, e.g. new genetic stock, biological
3)
control, hunting, pets, or ornamental trade. These may be introduced legally
or illegally (smuggled) into an area. A further layer of complexity arises when
one community considers an organism invasive and another community
(often in the same country) considers the species benefi cial.
h e volume of human-facilitated movement of goods and organisms, and
people travelling around the globe is huge and increasing every year. h ese move-
ments provide pathways that are possibly the most signifi cant sources of poten-
tial invasive organisms. Every traveller and item of goods that are imported into
a country potentially provides a pathway for an invasive species. h e following
describes some data of known movements of people and goods in two countries
with relatively well-controlled borders, the USA and Australia. h ey give some
idea of the magnitude of the task of minimizing the risk of invasive species entering
a country. Both the USA and Australia have invested heavily in the prevention of
entry of invasive organisms, as well as in management of pest incursions. h e USA
has a mix of long land borders and sea borders. Australia is entirely surrounded by
sea with only one area in close proximity to another country.
h e USA intercepted about 325,000 pests between 1991-96, and inspected
over 315,000 ships. In 1996, they inspected over 66 million passengers (APHIS
web facts). Australia intercepted about 140,000 pests between 1993-2003. In the
year 2006-07 there were 1.6 million sea cargo containers inspected; rising to 1.8
million in 2007-08—an increase of over 10% in one year. Currently12 million
air passengers are screened each year and around 45,000 items of quarantine con-
cern are seized every month and about a quarter of these are undeclared—there
