Bent-wing bats and wind farms: Two sides of the environmental equation?


Driving north out of Canberra, I am always struck by the arresting sight of Lake George. It is a vast, flat expanse of land and more often than not, devoid of water. Looking beyond Lake George, perched atop of rolling hills is a curious collection of giant fans. A wind farm. For Joe Hockey, this is a sight that utterly disgusts him. Whilst I don’t harbour Hockey’s disgust, I think this sight represents the complexity of today’s environmental problems, particularly the current trend of ‘trading off’ between benefits.

Amongst the debate about solutions to climate change and the need for sustainable development, the viability of renewable energy is a contentious issue. There is great potential for renewable energy to make larger contributions to the National Energy Market, particularly around the ACT region. However, as with any decision to develop land, the decision to approve a wind farm is always a question of weighing up a number of considerations. So, what are some of the trade-offs associated with the development of a wind farm?

  • Benefits to the greater public through increased access to renewable energy
  • Impacts on local community: noise and visual pollution, contentious impacts on human health (hyperlink) but also more jobs for the local community
  • Impacts on fauna such as bats, lizards and birds
  • Clearing of native vegetation

There is a need for adequate information about each of the above considerations, for government departments to make an informed decision in approving the development of wind farms. In the case of monitoring species, as Chief Justice Brian Preston of the NSW Land and Environment Court found in the case of Taralga Landscape Guardians v Minister for Planning, it’s not ideal to wait for environmental litigation to spur the collection of adequate scientific information.

Luckily for the eastern bentwing-bat, (Miniopterus schreibersii oceanensis) a regular monitoring scheme has taken place every year for the past eight years under the direction of Doug Mills, an officer with the NSW Office of Environment and Heritage. The eastern bentwing-bat is currently listed a vulnerable species in NSW. It is vulnerability probably lies in its specific temperature and humidity requirements when it comes to roosting.

Eastern Bentwing-bat

Church Cave, near Wee Jasper is one maternity cave known to the OEH. As there are plans to develop wind farms within the eastern bent-wing bat’s foraging and migratory paths, monitoring bat populations is critical to ensuring we have enough information to make an informed management decision. Doug monitors the maternal colony for about 3 months over the summer.

Monitoring bats involves filming bats as they fly out of Church cave on their nightly foraging trip. The bats are recorded using an infrared camera. This video is then processed using a program developed by US army engineers which essentially counts the number of ‘hotspots’ (bats) leaving the cave. Doug also collects data in real time by visually counting the number of bats leaving the cave for one minute every 10 minutes. At peak traffic times, this is 600 bats per minute! (Have a go for yourself here) This year Doug recorded an increase in population numbers, possibly due to the relatively mild summer.

Monitoring information collected at Church Cave can be used to manage wind farm developments in the region and their potential impacts on native fauna. For example, the NSW Government could manage the eastern bentwing-bat’s vulnerability by imposing a condition on wind farm operators to conduct an ongoing tracking, monitoring and reporting scheme. These results could be measured against existing data.

u4838886 Gaby Ho (A big thanks to Doug Mills for letting me tag along)



About Biodiversity Conservation Blog

I am an Associate Professor at The Australian National University and convene a (very awesome) course called Biodiversity Conservation. Myself and students in the course contribute to this blog.
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1 Response to Bent-wing bats and wind farms: Two sides of the environmental equation?

  1. Chloe says:

    Interesting blog! Some challenging issues regarding wind farms. I’d be interested to know what types of impacts wind farms might have on the Church Cave population, and what options there might be to mitigate negative effects?

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