Platypuses have been confirmed living in waterways near urban areas in Sydney's northern fringe for the first time since 1998.
Key points:
- The discovery confirms DNA and anecdotal evidence of platypus sightings in north-west Sydney
- Council is running information sessions this month to educate residents about living with the monotremes
- Pollution and habitat loss are big threats to the population, a researcher says
Following sightings and DNA evidence, researchers with Cattai Hills Environment Network (CHEN) set up nets and captured a healthy platypus in the Cattai Creek catchment in Sydney's Hills District.
Western Sydney University ecologist Michelle Ryan says she's surprised to find them so close to urban areas.
"Those creek systems really face increasing pressures and development pretty much goes up right up to the creek," Dr Ryan says.
"It was really good to see that they're able to, at the moment, withstand that development."
The environmental group and researchers found DNA evidence of the monotremes living in the catchment zone in 2020.
In addition to the capture of the healthy platypus in February, this evidence has led the group to believe there are at least 18 in the creek system that runs from Castle Hill to the Hawkesbury River.
It confirms anecdotal evidence of sightings in the area, which CHEN has been trying to confirm since the group's foundation in 2016.
"The fishermen would keep telling us that they'd seen one," CHEN chair Sue Martin says.
"It looks like we've got a healthy population but we need to do more study."
"This was a very exciting discovery," Hills Shire Mayor Peter Gangemi says.
"It shows that our waterways and the biodiversity of our catchment are very positive."
'They need a healthy ecosystem'
The discovery just minutes from homes and development has brought into focus the need to protect the habitat.
Dr Ryan says there is a risk of damage or removal of their environment.
"Plastic bags, hair ties, elastic bands can all cause really horrific damage to platypus and can cause death," Dr Ryan said.
"All those water bugs that the platypus eats is what really gets impacted by pollution, which then has an indirect impact on platypus.
"They need a healthy ecosystem to survive."
Cr Gangemi says most development in the council area is near train stations away from the platypus habitat.
The mayor says council has engaged CHEN to prepare a platypus strategy for council.
How to help the platypus
The discovery has prompted The Hills Shire Council to hold information sessions for residents about how to live near platypus environments.
Workshops combining with CHEN will focus on bushland restoration and how to sustain local waterways.
Dr Ryan says it's "simple" things residents do at home that can help maintain healthy water quality in nearby streams.
"Simple things like washing your car on your lawn, making sure you don't litter and remove any litter that you have," Dr Ryan says.
"Don't blow your leaves and your grass clippings down the stormwater drain."
Dr Ryan suggests joining local bushcare groups and helping replant vegetation in riparian zones can also help the platypus.
"You don't need to live on a creek system to really help the platypus population."