Melbourne Water Urban Platypus Program: autumn 2015
04 May, 2015
The Melbourne Water Urban Platypus Program is a collaboration between Melbourne Water and cesar (platypusSPOT). This research aims to investigate the status of platypus populations throughout the greater Melbourne region and identify threats (cesaraustralia.com/latest-news/wildlife-ecology/platypus-numbers-highest-in-years-for-greater-melbourne-region). This is done primarily through widespread live-trapping surveys (tag and release) at fixed locations in autumn and spring each year to understand how populations are changing over time.
We are now about half way through our autumn survey season and results have been mixed. Overall, our catch rates are close to the seasonal average that we have seen over the past 7 years. Relatively good results have been recorded at Tarago, Labertouche, Warburton, and Werribee. However at several other locations where we expect to catch platypuses, results have been disappointing, particularly early in autumn. This is typical of platypus surveys with high variation between surveys due to low platypus numbers and a number of factors that can impact our probability of capturing animals on any given night. Over time, this variability is smoothed out and the population trends become clearer which is why long-term monitoring is so important.
During early autumn, conditions were extremely dry and water level and flow in many streams was very low. It seems like these conditions impact our catch rates as platypuses may be less likely to move along streams and restrict themselves to deeper pools where they are safe from predators. If platypuses do not move around as much (and they typically forage over several km’s each night), they are less likely to encounter our nets and be captured. Thankfully, captures have increased over recent weeks, coinciding with some extra rainfall and the survey season is looking much more promising.
You can help us understand the status of platypuses across Melbourne (and Australia-wide) by submitting your sightings to platypusSPOT.org.
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