Environmental Engineering Reference
In-Depth Information
There is a growing body of science for survey design and appropriate methods to
extrapolate from survey results to obtain valid estimates of the numbers of animals
killed (Huso
2011
; Korner-Neivergelt et al.
2011
; Muir and Stewart
2013
; Perón
et al.
2013
). However, while this science is available, with the exception of Hull
et al. (
2013b
) and Hydro Tasmania (
2012
), the methods used to derive mortality
estimates for Australian wind farms from field data have not accompanied pub-
lished results. The information collated above is simply the reported numbers of
fatalities detected at the wind farms concerned and so does not provide for estima-
tion of total mortality for any taxa.
Acciona Energy (
2012
)reportedatotalof61fatalitiesof14birdspeciesdetected
at monitored turbines. They extrapolated these results to allow for undetected fatali-
ties and for all turbines at Waubra, and gave an estimate for all species combined, of
1.5birdsperturbineperannum.
Based on the number of monitored turbines, the collision rates for all species
combined were 1.7 birds per turbine per annum at Bluff Point and 0.9 birds per
turbine per annum at Studland Bay (Hydro Tasmania
2012
). An area around the
base of approximately one quarter of the turbines at those wind farms was fenced to
exclude scavengers and thus control for removal of carcasses (Hull et al.
2013b
).
Wind Turbine Collisions and Other Anthropogenic
Sources of Fauna Mortality
There are many human causes of fauna mortality, some intentional and some not;
some direct and some indirect. It is not the purpose of this paper to explore philo-
sophical aspects, but it is safe to assume that increased mortality rates resulting from
any human activity that contributes to the decline of a species is undesirable.
Since there is a widespread concern about avian mortalities due to wind turbine
collisions, ideally we ought to be able to compare them with other anthropogenic
causes of mortality, including those associated with different types of power genera-
tion and supply. In Australia, direct anthropogenic causes of avian mortalities
include road traffic, electricity transmission and distribution lines, tall structures
(especially those that are artificially lit) and illegal persecution, not to mention on-
going removal of habitats. However, fauna mortalities resulting from the great
majority of human activities are simply not measured, so we have no data to com-
pare these with the wind industry. The monitoring and counting of bird and bat
fatalities required of the wind energy industry is unlike that for any other sector in
Australia. It is worth noting that when regulatory approval processes for wind farms
in Australia have required pre-construction estimation and/or post-construction
monitoring of effects on particular species, they have usually required the results to
be determined to the precise number of individual bird or bat fatalities.
This raises interesting questions not so much about whether one activity results
in more or less bird and bat deaths than other, but about how we as a community
view different activities that result in fauna deaths. Two examples illustrate my
point. The first relates to electricity generation and the second to aviation.
