Koalas, friends, and foes -- the application of airborne eDNA for the
biomonitoring of threatened species
Abstract
Perched high up in a Eucalyptus tree, swaying from side to side, lies a
sleepy koala unaware of the means spent each year trying to obtain
accurate baseline information about its presence. We have thrown all we
could at it, from wildlife surveys to night spotting, bioacoustics,
detection dogs, and drones equipped with thermal cameras. Yet, whilst
critical to its conservation and management efforts, finding a koala
remains an ambitious, time-consuming, and costly endeavour often
producing insufficient results. However, little did we know that traces
of koalas’ presence and that of its predators along with other native,
domesticated, and invasive species, float in the air and can be detected
using metagenomics. This study and despite high levels of co-sampled
non-target DNA (e.g. humans and domesticated animals) confirms that
koalas, species belonging to the wallaby and possum family and threats
such as domestic dogs (a major predator contributing to koala population
declines) can successfully be detected by sampling airborne particles.
Together, it demonstrates the potential of airborne eDNA for the
detection of terrestrial wildlife under natural conditions and presents
achievable optimisation steps to increase its field applicability and
validity.