Environmental Engineering Reference
In-Depth Information
We consider there are three possible effects that wind farms may have on
brolgas:
1. Individuals may collide with turbine blades;
2. Birds may avoid or abandon areas due to the presence of turbines and associated
infrastructure; and/or
3. They may be prevented from their natural movements if they perceive multiple
turbines clustered across an area as a barrier.
DuetotherecentdevelopmentofthewindindustryinAustralia,nostudieshave
been undertaken on the impacts of wind farms on brolgas and no collisions with
wind farms have been reported. No crane mortalities have been recorded in the
United States of America (Erickson et al.
2001
), however in Texas there is some
evidence that wind turbines negatively affect sandhill crane
Grus canadensis
distri-
bution,foragingandroostingbehaviour(Navarette
2011
).
The Victorian Government has been pro-active and drafted guidelines in relation
towindfarmsandbrolgasinVictoria(DSE
2012
). The objectives of the guidelines
are to 'manage the cumulative impact of multiple wind farms … in the brolga's
range in Victoria, so that there is no
net effect
on the population'. The document
establishes an assessment methodology for potential wind farms, and this follows a
staged risk assessment process consistent with the Australian Wind Energy
Association (AusWEA) guidelines (AusWEA
2005
).
Aerial surveys are recommended to identify brolga breeding sites, and are
includedaspartofa'LevelTwoAssessment'(DSE
2012
: p. 10). Aerial surveys for
craneshavebeenusedelsewherewithhighsuccess.ForinstanceinSouthAfrica
for blue crane
Anthropoides paradiseus,
grey crowned crane
Balearica regulorum
and wattled crane
Bugeranus carunculatus
to determine population numbers
(McCann
2001
);inChinatolocatenestsandindividualsofthered-crownedcrane
Grus japonensis
(Qian et al.
2012
); and in Mexico to determine distribution and
abundance of sandhill crane
Grus canadensis
(Dreweinetal.
1996
). Here we report
on aerial surveys for brolga nests in south-western Victoria, Australia, in areas, in
and surrounding, proposed wind farms. We then consider the effectiveness and
adequacy of single surveys, and more generally consider the usefulness of aerial
surveys as a search method for this species.
Methods
Aerial Survey
The aerial surveys were undertaken at appropriate times of the year (breeding
season), based on the activity and status of known nest sites during that year. An
area of interest for the aerial surveys was defined as the boundary of a proposed
wind farm and a buffer of 20 km. This area was plotted in GIS (ESRI ArcMap
10.1), and transects were overlain on this whole area at 1,000 or 500 m intervals
