By Dr Michael Smith, South-west Regional Ecologist
American inventor, Dean Kamen, once said, “Every once in a while, a new technology, an old problem and a big idea turn into an innovation”. In many ways, Australian Wildlife Conservancy has adopted this philosophy when it comes to improving our approach for monitoring wildlife. At AWC we are trialling and deploying a suite of exciting new technologies in our science program. Three new technologies being investigated in Western Australia include the use of:
1. Drones fitted with thermal cameras to monitor reintroduced mammals;
2. DNA extracted from animal scats to estimate population sizes of cryptic species; and
3. Deploying acoustic recorders to monitor birds, frogs and bats.
Counting animals using drones
In June 2019, AWC staff and Travis Marshall, from technology firm C4D Intel, travelled to AWC’s Faure Island Wildlife Sanctuary, in Shark Bay, WA, to trial the use of a drone to monitor reintroduced mammals. AWC has reintroduced four threatened mammal species to Faure: the Burrowing Bettong (Bettongia lesueur), Banded Hare-wallaby (Lagostrophus fasciatus), Western Barred Bandicoot (also known as the Shark Bay Bandicoot, Perameles bougainville) and Shark Bay Mouse (Pseudomys fieldi). AWC currently monitors these species through spotlighting, trapping and track surveys. However, spotlight surveys are challenging because of the dense vegetation, and the last three species are cryptic and difficult to trap.
On Faure Island, AWC trialled the use of a drone, the DJI M210 Aircraft, fitted with a FLIR XT2 dual thermal/RGB sensor to determine whether:
1. Different species could be detected and differentiated using thermal imagery; and
2. The behaviour of reintroduced species introduced a bias to population estimates.
We found the thermal camera was excellent at detecting mammals and may be an effective tool for monitoring bandicoots, but the limited resolution made it difficult to distinguish between Burrowing Bettongs and Banded Hare-wallabies, which are both small macropods. Footage showed that Burrowing Bettongs tended to ‘investigate’ people as they walked through the bush, potentially biasing population estimates through double counting. Even so, estimates of population size derived from the drone footage were comparable to those generated by spotlight surveys, probably because some individuals are hidden by dense scrub during spotlighting.
Counting animals via their scats
At AWC’s Mt Gibson Wildlife Sanctuary, eight threatened mammal species have been reintroduced, including Banded Hare-wallabies and Greater Bilbies (Macrotis lagotis). Both species are difficult to survey; they generally will not enter traps, cannot be individually recognised from photos or in thick vegetation, and are challenging to monitor via spotlight searches.
A novel approach for monitoring these species involves extracting DNA from scats and using this information to estimate population size. AWC has trialled this method on Bilbies at Mt Gibson, in collaboration with Martin Dziminski from the West Australian Department of Biodiversity, Conservation and Attractions (DBCA). We conducted an initial trial shortly after Bilbies were reintroduced, when we knew exactly how many animals were in the population. Trial results provided a very good estimate of the population size.
© Brad Leue/AWC
A larger trial has now been undertaken by sampling scats across the 7,800 hectare fenced area at Mt Gibson, with results pending. We intend to use a similar method for Banded Hare-wallabies, in collaboration with DBCA. If successful, it will provide a new methodology for monitoring population sizes of elusive species.
Detecting animals through sound
Detecting birds and frogs by their calls is a skill developed by many ecologists, but comprehensive surveys are expensive and time consuming. For species that call only after certain environmental triggers (such as frogs after rain), planning surveys in advance can be challenging.
Deploying acoustic monitors in the field, rather than people, is an exciting alternative. The recent development of low cost, programmable and robust acoustic monitors has facilitated their use in routine ecological monitoring. AWC’s science team has successfully trialled ’Audiomoth’ devices for monitoring birds on Faure Island, and frogs on Karakamia and Paruna Wildlife Sanctuaries. In other regions, AWC ecologists have deployed ‘Songmeter’ devices for monitoring frogs, birds and microbats. Combined with developments in artificial intelligence, these technologies have the potential to provide new and more efficient methods for monitoring Australia’s threatened wildlife.
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