A decline in population numbers for the evasive platypus

Fifteen years of platypus surveys has indicated an overall decline in platypus numbers in many locations throughout greater Melbourne. 

cesar has conducted intensive biannual platypus surveys and collated catch rates from other historical surveys dating back to 1995.

While the data doesn’t allow for a rigorous assessment of platypus population sizes, the general trends in catch rates are indicating this concerning decline in platypus numbers.

According to Josh Griffiths, who has studied the ecology of the platypus since 2007 and is a senior wildlife ecology consultant at cesar, there are a number of factors that could have lead to this result.

“It appears that one of the primary factors behind this decline is the extended drought conditions experienced throughout Victoria over the last decade. However, other factors, such as habitat fragmentation, poor land use practices, predation and pollution all have negative impacts on platypus numbers.” Josh Griffiths.

While the decline is concerning there is still much more to be learnt about one of Australia’s most iconic and unusual creatures. Little is known about its biology, ecology, and behaviour. Also, because they are difficult to catch, at this stage there is no reliable method to estimate population sizes and trends.

cesar is working to find out more about the platypus with a unique and extremely important long term monitoring project of platypuses in an urban environment.

Josh Griffiths currently manages this monitoring project in conjunction with Melbourne Water– the Melbourne Water Urban Platypus Program. This involves biannual surveys of platypus populations at a number of locations throughout the greater Melbourne area from Werribee to Warburton.

The next platypus survey season is due to start in March 2011 and run throughout autumn.

Cover image: Photo by Josh Griffiths, Cesar Australia

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