Annual trapping occurs in the start of March each year, with the session occurring for 5 consecutive days. 2018 marked the 20th year that Arid Recovery has conducted annual pitfall trapping, alternating each year between dune and swale sites, both inside and outside the reserve.
It cannot be done without a small army of staff, interns and volunteers. This year we had 19 people, split across 4 teams, including staff from Arid Recovery, Bush Heritage Australia, the SA Department for Environment and Water (DEW), Mulligan’s Flat Woodland Sanctuary and BHP Olympic Dam and volunteers.
This year, we were trapping on the dunes. Our first day started with setting up a low fence-line running through the middle of our pitfall traps, which thankfully have already been dug in for us. Each site consisted of two lines of pitfalls with six pitfall holes on each line. This year, for the first time, we also trialed putting false floors in the bottom of pits – to provide small reptiles with a place to hide from any mammals that were also caught.
After each site was set up, the lids of each pit were removed, ready for critters to fall on in. Each site was checked for all animals and invertebrates in the early mornings at sunrise and in the late afternoon as the sun was setting. All vertebrates caught in the traps were placed in individual catch bags and then taken back to the lab for processing. Processing of the animals involved determining sex, measuring their body parts and weighing each individual animal. After being processed, the animals were kept safe in the lab until evening and were released at the same site they were captured.
Every annual trapping session that we conduct each year is just as important as the next as it provides Arid Recovery with accurate long-term data. This allows comparisons between the abundance and diversity of the small mammals and reptiles found inside and outside the reserve to be made over time. This in turn can help determine whether specific animals are doing better in specific places.
Painted Dragon (Ctenophorus pictus). Photo: Sarah Voumard.
This year we caught and released a whopping total of 719 animals (including 563 individual animals, as some were recaptured during the session). There were 420 reptiles and 299 mammals, consistent with previous years trends of capturing more reptiles than mammals. We also caught 462 invertebrates.
The two main species of mammals caught were spinifex hopping mice (246) and plains mice (49). We caught more hopping mice and less plains mice this year compared to last year as hopping mice prefer to inhabit dune systems and plains mice prefer swales. The most common reptile, with 185 captures, was also a dune-specialist – the southern sandslider (Lerista labialis).
Intern Kirra Bailey with a central knob-tailed gecko (Nephrurus levis). Photo: Sophie Wilkins.
Arid Recovery would like to express gratitude towards all the volunteers who came to help out. Without them, it wouldn’t have been possible. Also, a special shout-out to the Roxby Downs children who gave up their weekend to join us…we see some great budding ecologists there!