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Abstract
Invasive animal pests inflict many kinds of damage on the environment, and threaten
native fauna and flora. We attempt to value the benefits from the extra biodiversity
that is protected if these threats were removed. The NSW Rural Lands Protection
Board is a major agency that undertakes pest control, and is organised into 48 districts
across the state. A cross-sectional set of data on Board expenditures, pest abundance,
and environmental and climatic characteristics, was compiled by district and
analysed. The number of threatened native plant and animal species increases with
pest abundance and with the total number of native species present in the district. But
the number of threatened species decreases as Board expenditures on pest control
increase. The value of preserving an extra species is derived from these changes in
expenditure, following conventional economic principles. Then the potential gain in
economic surplus is estimated if the threats to biodiversity were removed. The results
so far suggest that the value of the total benefit of protecting an extra species is at
least $44,250 per year, and the potential gain in surplus for New South Wales if the
threats were removed is at least $132m per year. This change in surplus is also the
total economic loss because invasive pests threaten native flora and fauna. If only
half the native species could be protected, the avoidable economic loss is at least
$95.7m per year. The assumptions and limitations of these estimates are discussed.