DNA test of Skippy’s scat

In order to manage vulnerable kangaroo populations, it is important to identify the distribution of species across particular areas. Researchers at The University of Adelaide have developed a simple DNA test which identifies the animals from something they leave everywhere - their poo.

It is not uncommon for scat to be used to monitor populations, but surveys normally rely on visual identification; if similar-looking scats are misidentified, it can “have major impacts on the accuracy of abundance and distribution surveys of target species, wasting resources and misdirecting management and conservation actions”, according to the researchers.

“Despite their large size, kangaroos and wallabies are surprisingly difficult to see and count reliably,” said lead author Jessica Wadley. “Collecting droppings, or scats, provides a relatively simple and easy way to estimate the presence or absence of a species. But in this area of Queensland, where there were eight possible kangaroos and wallaby species with overlapping ranges, it’s difficult to correctly identify which species is leaving which scat.”

Thus, the team took a different approach, collecting 914 droppings from 53 sites across north-eastern Australia and successfully extracting DNA from 398 of the samples. A unique pattern of DNA fragmentation was developed for each of the eight species. The process eliminates the need for gene sequencing which is costly, time consuming and requires sophisticated laboratory equipment.

The test has already identified five species occurring well outside their known range, with the Eastern Grey Kangaroo 400 km outside its range. This has important implications for population management and conservation.

Co-author Dr Damien Fordham noted that the test, “allowed us to identify samples from the antilopine wallaroo, a species that is threatened by climate change.” This has enabled the team to carry out “more detailed genetic studies relating to the factors that influence its distribution.”

“The more information on the distribution of species, the better management decisions can be made, particularly in gauging potential land use and climate change impacts on biodiversity,” said Wadley.

The test can have other uses as well, with co-author Associate Professor Jeremy Austin suggesting, “The test could also be used to rapidly and cheaply identify the source of kangaroo meat and products to detect illegal hunting of protected species.”

The project is being conducted by the University of Adelaide’s Australian Centre for Ancient DNA (ACAD) and Environment Institute as part of a broader ecological study. It is described in the journal Wildlife Research.