Protecting vulnerable microbats through design – Wollongong

Work on a degraded stormwater culvert in Darkes Road will restart shortly after the project was put on hold to protect a colony of vulnerable microbats living in the infrastructure.

The microbats were discovered in May last year in the third cell, or section, of the culvert after repair and reinforcement works to the culvert’s two other cells had been finished.

Preparations for the repair works to the third cell was stopped immediately, and Council sought expert advice on how to protect the microbats.

Industry experts identified them as Southern Myotis microbats, which are listed as vulnerable under the NSW Biodiversity Conservation Act 2019. The experts’ research identified at least 10 bats at the site. They developed a Microbat Management Plan, which will allow the second stage of work to be completed.

“We’ve incorporated the Microbat Management Plan into our updated design for the culvert,” said Wollongong City Council’s Director of Infrastructure and Works Andrew Carfield.

“Under the Plan we’ll carry out the refurbishment works at a time of year when the bats aren’t breeding and when they’re not in their winter hibernation.

“Over the past few months we’ve been taking the steps set out in the Plan, such as monitoring known roost sites, installing wooden bat boxes near the culvert and we will shortly start the process of gradually blocking the culvert entrance to encourage the microbats to find an alterative home while the work is underway.

“With the completion of these steps, we will be ready for the second stage of works to get underway. While the works are being carried out, we will continue to make sure no microbats re-enter the culvert.”

Work on the culvert begins at the end of May, after a 12-week bat exclusion timeframe has been completed. The culvert works will take about 12 weeks, and the tender for this phase of work was awarded at Monday night’s Council meeting.

Once the repairs and refurbishment to the corroded concrete is finished, a permanent replacement microbat roost habitat will be placed into the refurbished culvert that resembles, replaces and enhances the roost habitat.

“I’d like to thank everyone for their patience with this project,” Mr Carfield said.

“Culverts like these are essential as they provide a channel for the movement of flood and stormwater and we need to repair and maintain them for the safety of our road users and community. However, it’s also important we protect the wildlife that may call them home.

“In this instance, the project may take a little longer than we had anticipated, but it’ll provide a positive outcome for residents of West Dapto as well as this local microbat population.”

Microbats Facts

  • Southern Myotis Microbats are known to roost in gaps, cracks, holes or crevices that are larger than 10mm or large enough for a microbat to crawl into.
  • Their roosting colonies are commonly made up of up to 24 individuals, although significantly larger groups have been identified.
  • This species of microbats use their large feet to trawl for small fish and air-breathing aquatic invertebrates.

Microbats overwinter – or hibernate – and use the fat stores they’ve gathered over spring, summer and autumn during this time. Exposure to noise, light and vibration can disturb bats that are overwintering.

Picture of the Southern myotis (c) R and A Williams Australian Museum

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