The Great Australian Platypus Search update: spring 2018 results

The Great Australian Platypus Search (GAPS), a collaboration between cesar, San Diego Zoo Global, and the University of Melbourne, is well under way with the first round of results just in.

GAPS is using environmental DNA (eDNA) technology to assess the current distribution of platypuses and to evaluate the importance of major threats.

This technology allows the detection of a target species’ DNA from water samples with very high sensitivity, allowing data on a species distribution to be determined cost-effectively at many sites and over very large spatial scales, which is important for a widely distributed species such as the platypus.

Such data allow for a systematic investigation of the impacts of key threats on a species with high statistical power (high confidence). 

GAPS launched in early 2018, but the early months were spent planning and designing the project. As with any research project, we simply can’t collect data everywhere! Good science relies on a rigorous sampling design that has the statistical power to answer the key questions and considers current knowledge of the species’ ecology and behaviour.

A comprehensive sampling program was established, identifying approximately 200 subcatchments throughout Victoria and south-eastern NSW (see map) from a random stratified design based on different land use and river disturbance categories.

Within subcatchments, water samples for eDNA analysis were collected at 3-10 sites to provide a high degree of confidence in determining presence or absence of platypuses within each subcatchment. Habitat assessments were also undertaken at each site, considering six variables known to be important for platypus occurrence.

The first round of GAPS fieldwork was undertaken during spring 2018 to target the platypus breeding season.

Despite very dry conditions limiting sampling opportunities, water samples were collected from 31 subcatchments. When combined with complementary data from local projects we have undertaken with Melbourne Water, Wimmera CMA, Project Platypus, Upper Barwon Landcare Network, Upper Campaspe Landcare Network, Glenelg-Hopkins CMA, and Blacktown Council, we now have data from a massive 627 sites across 99 subcatchments!

This is a great start to a very important and ambitious project – by far the largest ever attempted for platypuses.

A quick glance at this preliminary data is already revealing some worrying signs. Platypuses were not detected in a number of subcatchments in the drier, agricultural regions of western Victoria where we would predict impacts of drought and land clearing to be most severe.

The team will be heading out into the field again shortly to start sampling again, focussing on eastern Victoria and southern NSW where platypus populations may be more extensive (we hope!).

Stay tuned for more GAPS updates throughout 2019 by following platypusSPOT on Facebook or Twitter. And you can actually be part of this amazing project by recording any platypus sightings to or via the platypusSPOT app.

Cover image: Photo by Bildagentur Zoonar GmbH, Shutterstock

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