deakin

Getting to know Gariwerd

From burning to booming (and back again) - a tale of fire and water. 

Back in 2006, a major wildfire burned approximately 85,000 hectares of the Grampians National Park. Lightning sparked the blaze and a burning question – how will the system respond to this large, high intensity fire? Although we didn’t know it at the time, this event was the forerunner to the birth of a long term study and partnership. Every year for the past nine years, a Deakin Wildlife and Conservation Biology Honours student has taken on the task of delivering the Grampians mammal trapping.  Without fail, these students have (with some trepidation) dived into the experience before emerging triumphant and as confident and competent researchers. 

We annually trap 36 study sites throughout the park. When the trapping first began, we were inundated by exotic species (mostly the invasive house mouse). The region was recently burnt but was also in the grips of the ‘Millennium Drought’ – not an ideal situation. After a few more years of poor rain, the landscape was drenched for the first time in many years and with that, the drought was broken (but sadly not for long!). With the downpour came an uprising.

In 2012, 18 months after the deluge, the mammal numbers had boomed, doubling from the previous year and almost four times the numbers of the first year. The sheer amount of mammals was not the only change; the composition had shifted to a landscape dominated by native species. This was an exciting time with the smoky mouse being detected for the first time in the study, as well as an albino heath mouse and many bandicoots carrying pouch young captured.

While these conditions seemed to be conducive to small mammals, it presented a number of challenges for our research team. Many roads crumbled during the onslaught of rain, making access incredibly difficult and time consuming. After many kilometres at a snail’s pace, help from the Parks Victoria quad bike, and a series of turnarounds, trapping was completed. 

Following on from this boom the rainfall once again began to decline. As a result, the mammal numbers followed suit before stabilising at low numbers from 2014 onwards. Native species are still managing to dominate the landscape, although in the last two years the number of house mice has begun to increase – funnily enough there were 127 captures in both 2015 and 2016, what are the chances!? As these conditions have unfolded, we have seen an incredible opportunity to investigate the impacts of future climate change. Future scenarios outline an era where there is a highly variable climate, with protracted periods of below average rainfall punctuated by flooding events. It was like looking in a mirror! 

Since we began our investigation into the effects of variable climate, our research has yielded some unexpected results. What we have found indicates that our temperate system is acting much like the arid regions of Australia. In arid zones, mammals experience booms and busts associated with the sporadic rainfall that these areas receive. What we’ve found is that our system (originally thought to be more predictable and stable in that sense) was responding this way as well. 

With native species showing a preference for areas that remain unburnt for longer, the pattern of wildfire occurrence becomes increasingly worrying; with larger and more regular fires looking to become the norm, the future of our native species may be threatened.  In the last 10 years alone, approximately 90% of the Grampians National Park has experienced wildfire (in 2006, 2013 and 2014!), leaving very few long unburnt areas. This means that the distribution of fire age classes is less than optimal for small mammals.

The interaction between the effects of fire and climate create a complex web to manage for biodiversity; it does, however, provide hope. We have seen populations bounce back from almost undetectable levels, so as long as conditions don’t remain sub-optimal for extended periods and large, high intensity wildfires do not increase in number, experienced species should have the capacity to recover.

Our experience in the Grampians has been amazing, and thought-provoking. We have realised the significance of and invaluable knowledge obtained from long term studies, especially when facing the uncertainty of the effects of future climate change. It allows us to observe the peaks and troughs experienced by a system that may have been overlooked or undetectable in a snap shot study. While snap shot studies are important, we need to value and support long term studies, particularly as the onset of climate change intensifies.

Check out our latest paper from our Grampians research here.  

Follow our research on Twitter @Wild_Gramps


This is a guest post by Deakin University PhD student Susannah Hale and Associate Professor John White.

All images taken by Susannah Hale

Big Desert Adventures: Part Three

Since settlement times, Victoria’s Mallee region has captured the public imagination. Upon digging up old newspaper articles documenting early expeditions to the region, tales of ‘tiger cats’ hell bent on attacking people, and medium-sized marsupials (e.g. bettongs and bandicoots) in apparent plague proportions, are common. Over time, these bush yarns have only enhanced the region’s mystique and reputation as somewhat of a wild frontier. 

Once upon a time quolls and dingoes appeared to rule the Big Desert/Wyperfeld region from the top of the food web. It’s now a slightly different storey, but no less intriguing.  

The third instalment of my Big Desert Adventures blog is being hosted on Euan Ritchie's website. To find out what my camera traps have revealed so far, read on here.


Big Desert Adventures: Part Two

I’ve just returned from my first foray into Victoria’s spectacular Big Desert, and it was every bit as successful as hoped. Currently, there are 35 predator cameras and 35 prey cameras deployed across 35 sites within the Big Desert Wilderness Park, Big Desert State Forest and the Wyperfeld National Park. It really is a beautiful region, hosting a range of ecosystems not seen anywhere else in Victoria.

A picturesque Big Desert sunrise. Photo: William Geary

A picturesque Big Desert sunrise. Photo: William Geary

With any luck, there’ll be a nice array of critters dancing in front of my cameras as you read this. Specifically, at each location I’m targeting Dingoes, Red Foxes and Feral Cats with the predator cameras and a bunch of small mammals (including the Silky Desert Mouse, Mitchells Hopping Mouse and the House Mouse) with the prey cameras. Why these animals though? Well, have a read of my last article describing the background of my project in a little more detail.

You might be wondering what these cameras I’m speaking of look like, so here’s some examples below. The movement of heat (i.e. a body) across a detection zone triggers the cameras, taking video or photos in response. However, that’s where the similarities end; the predator cameras are outward facing, in order to observe larger animals. On the other hand, the prey cameras face downwards as this aids the identification of many small mammal species. Without the help of camera traps, there are quite a few species I wouldn’t even be able to detect, making them an essential tool for any wildlife ecologist. 

The downward facing prey camera, complete with delicious peanut buttery bait. Photo: William Geary. 

The downward facing prey camera, complete with delicious peanut buttery bait. Photo: William Geary. 

The outward facing predator camera in some early successional heathland. Photo: William Geary

The outward facing predator camera in some early successional heathland. Photo: William Geary

In addition, I surveyed for predator scats at each site, collecting nearly 100 samples across nearly 90km worth of transects. Helpfully, Canid and fox scats are generally very easy to spot as they tend to be placed quite prominently in order to mark territory. These will give me another insight into what habitats the local predators are using most. We’ll also be sending the scats off for diet analysis to find out just what’s on the menu in the Big Desert for our furry carnivores.

At our last site we got a true indication of just how merciless fire can be in the mallee (see the photo below). With absolutely nothing left, save for one or two coppicing Eucalypts, one really gets an idea of what the phrase ‘resetting successional trajectory to year zero’ means. Or, in layman’s terms, clearing the ecological slate and starting from scratch. There are very few places in Victoria where succession can be viewed as vividly as in the mallee.

Fire can be absolutely devastating in the Mallee, leaving very little behind. Photo: William Geary

Fire can be absolutely devastating in the Mallee, leaving very little behind. Photo: William Geary

Having traversed a myriad of sandy 4WD tracks, both in the car and on foot, one really gets an appreciation of just how vast and untouched the region is. The sensation of looking out from the top of a dune, with not a single man-made feature in sight is something pretty special. This was compounded at one point with three or four Wedge Tailed Eagles flying overhead whilst gazing off into the distance. Importantly, the Big Desert’s vastness shouldn’t be mistaken for emptiness, with the place absolutely crawling with wildlife.

The vast landscape of the Big Desert. Photo: William Geary

The vast landscape of the Big Desert. Photo: William Geary

Throughout our expedition we managed to happen across a range of reptiles (Mallee Dragons, a Burton’s Legless Lizard & Stumpy Tailed Lizards) as well as the standard mobs of Emus and Western Grey Kangaroos. However, perhaps the most fun aspect was deciphering the origin of the plethora of animal tracks found in the sandy soil. Everything from echidna and dingo to legless lizard and emu tracks were spotted. Following one particular track in the sand resulted in a particularly excellent encounter with a Burton’s Legless Lizard. A definite trip highlight.

Given the recent cold snap, the reptiles will be well and truly hidden away when the time comes for the next Big Desert Adventure. Despite this, I’ll hopefully have some exciting camera trap pictures to share, as well as more photos of the beautiful landscape that is Victoria’s mallee.