Just ask the locals: new way to tell if a species is native
15 February 2012
'You'll get the best advice from asking the locals' is a tip often used by travellers. It's also a radical new way to determine whether an introduced species has become a native species - by asking the other local species - according to research by Alexandra Carthey, a PhD student in the School of Biological Sciences at the University of Sydney, and her supervisor Associate Professor Peter Banks.
In a paper published in the journal PLoS One, Alex Carthey and Associate Professor Peter Banks explain that introduced species cannot remain eternally 'new' in an ecosystem, and therefore at some point must become 'locals' themselves.
"Native status is a big deal. It affects people's reaction to the species and where conservation dollars are spent," said Associate Professor Banks.
"Our study puts forward an objective criterion to determine the native status of a species - to 'ask' the local fauna it interacts with," explained Associate Professor Banks.
They suggest that as the other species adapt and learn to coexist with the once new species, it slowly becomes a native species in that ecosystem.
To investigate this process, the team used the dingo (Canis lupus dingo) as a case study, as its native status in Australia is disputed.
"Dingoes were introduced to Australia around 4 000 years ago, but there is debate around whether they should be classified as a native species or not," said Alex.
"We wanted to see how a vulnerable species, the bandicoot, Perameles nasuta, reacts to domestic dogs, Canis lupus familiaris, which are the same species as the dingo. We compared how bandicoots forage in urban backyards in households that have dogs, compared to those that have cats, which were more recently introduced," explained Alex.
While dingoes have been present in Australia for around 4 000 years, cats are fairly recent arrivals, having been introduced in Australia only about 150 years ago.
"We found that after thousands of years of interaction with dingoes, bandicoots will recognise the danger and avoid foraging in backyards with dogs, but will continue to visit yards of cat owners and petless households," said Alex.
"Our study suggests that bandicoots have come to fear dogs as predators and so avoid areas with dogs, while they are yet to recognise the threat cats pose as predators, as bandicoots haven't been in contact with cats for as long."
This novel approach to investigating whether dingoes have become native Australian animals is significant in light of the controversial debate over the status of dingoes and how that relates to wild dog management and conservation.
"Determining whether species are native or not is actually a worldwide conundrum. Scientists, governments and legislators have struggled with the question of how long it is before you can consider a 'new' species to be native," said Associate Professor Banks.
"It has been thought impossible to answer this question, but we propose a solution - the only real way to determine whether or not a species is native is to 'ask' the local wildlife it interacts with.
"In the system we studied, bandicoots are no longer naïve to dogs as predators, suggesting that at least some local species respond to dogs as they would to a native predator. This supports the argument for dingoes to be considered a native species. The lack of response to cats by bandicoots in our study suggests that, for these species, hundreds of years of coexistence may not be enough."
Read the paper in PLoS One at: www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0031804;jsessionid=5C2C936CE31618A4BA762BBB83FBFAA1
Contact: Katynna Gill
Phone: 02 9351 6997