Biology Reference
In-Depth Information
health risk to humans as well as its confinement to a small current new range in the US
would seem to offer almost ideal circumstances for its eradication. Fortunately, eradica-
tion is seemingly the goal in Washington and elsewhere in the US.
3.9 Invasive Plant Eradication: Common Features
of Success (and Failure)
Concerted attempts have been made to eradicate alien plants for more than one
hundred years. All such attempts, whether successes or failures, form the basis by
which we can detect features common to successful eradication campaigns. Some
of the conclusions below admittedly appear as common sense; however, others
appear initially counter-intuitive but nevertheless have a record of support. As a
result, it appears possible to form a “to do” and the equally valuable “do not do”
list of steps for eradication (Groves and Panetta 2002; Mack and Lonsdale 2002).
Underlying this list is attention to both the tactics (i.e., the specific tools used to
destroy the target species) as well as a comprehensive strategy (i.e., attention to the
larger geographic scale issues of curbing and eventually totally destroying the tar-
get species) (sensu Moody and Mack 1988).
1.
Further entry into the new range must be completely curtailed
. It is pointless to
initiate eradication as long as the opportunity persists for simultaneous reentry,
whether accidental or deliberate. Early in the US eradication campaign against
European barberry federal regulations were enacted to prohibit its sale (Kempton
1921). The
S. asiatica
eradication program in the US wisely imposed a quaran-
tine of farm implement movement between counties as an effective first-step to
minimize its inadvertent reintroduction into treated fields (Eplee 1981 and refer-
ences therein). Deliberate dispersal of a target species, such as a species still
valued in horticulture, must also be completely curtailed. Failure to stem such
dispersal renders any eradication effort pointless, e.g., as long as
E. crassipes
can still be purchased anywhere in the US (Isaacson 1996), no comprehensive
eradication of the plant in the US can be sensibly considered.
2.
The target species should be readily detectable
. As defined here, eradication
unlike control ultimately involves the destruction of all plants. This specificity
of action places a premium on detecting even isolated individuals. If target
plants are small or inconspicuous, or both, detection is obviously much ham-
pered. In contrast, successful eradications have commonly targeted large herba-
ceous perennials (
Hieracium pilosella, S. asiatica
) (Mack and Londale 2002) or
shrubs (
B. scoparia)
(Dodd 2004). A plant's conspicuousness is not, however, a
guarantee of its eradication (cf. early attempts to eradicate
E. crassipes
), only a
highly useful feature.
3.
The search terrain should be readily accessible
. Here again, common sense is
borne out in practice. Campaigns against
S. asiatica
and
B. scoparia
have been
conducted in low relief terrain in southeastern US and Western Australia,
