Biology Reference
In-Depth Information
these attributed predation to snakes (Fritts and McCoid, 1991). Fritts and McCoid
(1991) concluded that brown treesnakes were an apparent factor contributing to
Guam's inability to produce sufficient quantities of eggs for local consumption,
leading to high-cost import substitution of eggs from Australia and the United
States. As well as reducing the viability of a commercial poultry industry, increases
in agricultural insect pests attributed to the snake's extirpation of insectivorous
birds is argued to be partly responsible for Guam's agricultural decline since 1945
(United States Geological Survey, 2007). The snake also takes a toll on pets, prima-
rily puppies and cage birds, but the cost of this loss is unestimated (Rodda and
Savidge, 2007). Total costs of brown treesnakes to the United States have been
estimated at US$12 million/year (Pimentel et al., 2005), which includes damage
costs on Guam and funds expended to control the species and prevent its further
introduction elsewhere.
Poultry depredation has also been reported for
Varanus indicus
in Guam
(Crampton, 1921; Fritts and McCoid, 1991), the Northern Mariana Islands (Crampton,
1921; R.P. Owen, 1974; Wiles et al., 1990), Marshall Islands (Fulbeck, 1947), and
the Federated States of Micronesia (Uchida, 1966, 1967, 1969). The same species
is reported to reduce native populations of coconut crabs in Micronesia, leading to
an additional loss of protein to local villagers (Uchida, 1966, 1969). The related
Varanus niloticus
is reported to attack pets in Florida, United States (T. Campbell,
2005). In none of these instances are economic costs quantified.
The introduction of
Eleutherodactylus coqui
to Hawaii led to the prediction of
potential economic effects to the nursery industry, hotel industry, and residential
property values because of the noise pollution caused by the frogs' loud calls
(Kraus et al., 1999; Kraus and Campbell, 2002). Some of these effects have subse-
quently been documented. Negative effects of
E. coqui
on residential property values
on Hawaii Island alone have been estimated to be 0.16% of total value for houses
within 500m of an infestation and 0.12% for houses between 500-800m of an
infestation, leading to a potential loss of revenues of almost US$8 million/year as
frogs continue to spread (B.A. Kaiser and Burnett, 2006). Total costs would
increase accordingly should the frogs become well established on Maui or Oahu,
with their higher property values (B.A. Kaiser and Burnett, 2006). Realtors on
Hawaii Island now include declaration of coqui presence in sellers' disclosure
statements (Wu, 2005). An alleged failure to make such a declaration has led to the
first lawsuit generated by this pest invasion (Dayton, 2007). Since December 2004,
Guam has required nursery shipments from Hawaii to be certified as having been
treated prior to export with either a 16% citric-acid solution or a 42°C hot-water
drench for five minutes (D. Gee, Guam Department Agriculture, personal commu-
nication, 2007), treatments known to kill
E. coqui
. As well, plants imported from
Hawaii are temporarily quarantined, preference is given to bare-rooted plants, and
public education programs have been launched on Guam (Christy et al., 2007a).
Some additional cost to Hawaiian nursery growers must follow from these restric-
tions, but they have not yet been calculated.
Introduced
Bufo marinus
became a significant predator of honey bees (
Apis
mellifera
) in Australia and led to economic losses for apiarists and reduction in
