Mammals, mammals, more mammals, and reptiles too!

Graeme Finlayson (Ecologist)
Published 26 Mar 2021 
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Central Netted Dragon. Photo by Oisin Blunt<br/> Central Netted Dragon. Photo by Oisin Blunt
Broad-banded Sand-swimmer or Richardson’s skink (Eremiascincus richardsonii). Photo by Oisin Blunt<br/> Broad-banded Sand-swimmer or Richardson’s skink (Eremiascincus richardsonii). Photo by Oisin Blunt

Every year out at Arid Recovery Reserve, near Roxby Downs in outback South Australia, a small team of animal enthusiasts gather to conduct the annual monitoring of small vertebrates found inside and outside the reserve. For those that are not aware, Arid Recovery is an area of 123km² surrounded by a predator-proof fence, inside which a range of native species, extinct throughout South Australia, have been reintroduced. The reserve provides a refuge for these and other native species from the direct threat of predation by introduced mammals, such as foxes and feral cats.

In recent years, Bush Heritage staff have helped Arid Recovery by joining the survey as part of a partnership between the two organisations in the SA arid rangelands. Arid Recovery staff will return the favour later in the year for monitoring surveys on Bon Bon Station Reserve. This year, I was lucky enough to join the survey and led one of the four teams. I always enjoy the opportunity to visit Arid Recovery as many years ago it was where I spent a few months completing an internship on Burrowing Bettongs.

Annual trapping is also a great way to engage the younger generation, with school and university students volunteering their time to learn about the suite of native species that we all rarely see.

The survey includes sites from inside and outside the reserve, to compare the effect of removing predators and introduced species on the small vertebrate fauna. Each year alternates between dune and swale habitats. This year was swale sites, so the area between the classic outback sand dunes that includes areas known as gibber plains.

Four teams of 3-4 people set out each afternoon and morning to check pit traps, remove animals and place them in bags, and return to the lab to identify, weigh, measure, and determine the reproductive status of each animal. The week involves early starts and late finishes but the range of personalities and the anticipation of what might be looking up at you when you peer into a pit trap make it all worthwhile.

After a number of years of below-average rainfall, this year provided a welcome change, with mammal numbers increasing, both inside and outside the reserve.

In all, we finished with nine species of mammals (seven rodents and two dunnarts).

This included numerous Plains Mice (Pseudomys australis), a species that returned to the region after the fence was established back in the late 90s. Local numbers of this species had dropped right off with the drought, as had numbers of Forrest’s Mouse (Leggadina forresti), but both were once again recorded at a number of sites.

In addition, there was also a capture of the Desert Mouse (Pseudomys desertor), which has only been recorded in the reserve on a handful of occasions. All up, we captured 759 animals, with 22 reptile species and 9 mammals (and more than 300 total captures).

The data will form part of the long-term monitoring to assess the impact of predator removal and local reintroductions on the native species inside and outside the reserve, as well as the long-term dynamics of these amazing critters associated with rainfall and vegetation changes in the region.

Central Netted Dragon. Photo by Oisin Blunt<br/> Central Netted Dragon. Photo by Oisin Blunt
Broad-banded Sand-swimmer or Richardson’s skink (Eremiascincus richardsonii). Photo by Oisin Blunt<br/> Broad-banded Sand-swimmer or Richardson’s skink (Eremiascincus richardsonii). Photo by Oisin Blunt