Hard yakka digging pitfall holes at Edgbaston Reserve

Last week I was tasked with setting up of a series of permanent fauna and flora monitoring sites at Bush Heritage’s Edgbaston Reserve. When asked to do it I couldn’t help but suppress a groan. Don’t get me wrong, monitoring is essential – otherwise how would you know if your conservation management strategies are working? But the tiresome aspect of setting up a fauna monitoring site involves digging pitfall traps.

Pitfall traps are large buckets dug into the ground, several in a line. When opened, small mammals and reptiles are guided into them via a small ‘drift fence’ erected along the line. The catch data then provides information about changes to the diversity and abundance of the ground-dwelling fauna of Edgbaston Reserve overtime.

But digging holes in Australia’s outback is hard work. Have you ever wondered why the ground out here is the colour red? It’s because it’s old – very old. The red colour is caused by iron oxide in the soil – that’s right, the ground is literally rusting iron and I’d just been asked to dig a bunch of holes in it. Groan!

I needed help, so I turned to the Lake Eyre Basin Rangers. They're part of the Indigenous Land and Sea Ranger Program carrying out a range of natural resource management and cultural heritage protection work across the Channel Country. And thankfully they agreed to come out and spend a week helping me.

There are six main vegetation types at Edgbaston and we decided to set up the pitfall monitoring sites across three of them. We set up four independent sites in each vegetation type with each being a trap-line of four pits. It's important to replicate the monitoring sites within each vegetation type as this enables us to be more confident that the changes in fauna abundance and diversity that we find are representative of the whole reserve and not just at the spots we sample. But what this really means is a lot of digging. So we got to work.

Some sites proved to be relatively easy digging, such as the spinifex sites in the lowlands, which were quite sandy in places. The cracking clays of the Mitchell Grass Downs sites were also not much of a headache and together we got through them in good time.

But the beautiful looking ironbark woodland found across the top of the escarpment proved to be hard going. I knew it would be so I left these holes to last. Fortunately, the Lake Eyre Basin Rangers had learnt a technique from their previous fence-building jobs that made the work a whole lot easier – fill the difficult holes with water. It breaks up the hard soil as it goes down. It worked and our timing was perfect. When we finished our last pitfall line the clouds that had been threatening all afternoon opened up and drenched us.

In addition to the trap line sites we established another 12 monitor stations where we'll do bird and small mammal surveys, spotlight for arboreal mammals, search for reptiles and for indirect signs of animals such as their scats, tracks and scratches. We'll also do flora surveys there.

So all up, by the end of the week we'd finished setting up 24 permanent flora and fauna monitoring sites across six ecological communities including the installation of 48 pitfall traps spread across three ecological communities. This ensures that the flora and fauna of Edgbaston will be well monitored for years to come.

But it wasn’t all hard work. We also visited some of the mound springs that Edgbaston has to offer. Here we saw the threat that introduced mosquito fish pose to the endemic Red-finned Blue eye fish. We saw how Bush Heritage has installed exclusion fencing to keep the mosquito fish out and have also built remarkably natural-looking artificial mound springs to stock with blue-eyes as insurance populations.

Nearby there are some unbelievable fossil sites dating back to when Australia had an inland sea – but that’s a story for another time.

A massive thank you to the Lake Eyre Basin Rangers!