A year ago I posted about the formidable Hawkweed Eradication Program, which is primarily focused on the Alpine National Park of south-eastern Australia. All summer parks staff, private contractors and volunteers scour likely locations to weed out Hieracium species. Detector dogs Sally and Connor are now very much part of the action, too!
Last week we gathered in Falls Creek to evaluate Sally and Connor’s search skills in the Victorian environment. We sent them – plus a team of the High Plains’ proud volunteer searchers – to some specially selected plots where live hawkweeds were known to be hiding. The three search teams found almost all of those known plants, and additionally spotted several undocumented infestations!
Both projects address how we can best search for rare targets in ecological surveys. They’ll involve experimental design, data collection in the remote and ruggedly beautiful Alpine National Park, statistical modelling and conservation decision-making.
Jos’ and my project also rolls in concepts of novel search methods and how we can best integrate them into existing programs. It’s an opportunity to learn from the state government agencies managing a hawkweed eradication program as they investigate the combination of human search teams, trained dogs and unmanned aerial vehicles that will best detect every last hawkweed.
I’ve spent the past week in Kosciuszko National Park, contributing to the mammoth team effort eradicating hawkweeds (Hieracium species) from mainland Australia. Dozens of parks staff, state weeds staff, contractors and volunteers train their eyes on rosettes that could otherwise be mistaken for common daisies. Their goal is to find and kill every last one of these interlopers.
The searchers’ newest team-mate Sally prefers to follow her nose. She’s a working dog trained specifically to distinguish hawkweeds’ scent from the other plants occurring in the Alpine National Park. I’ve been helping set up fully- and partially- controlled experiments to evaluate detection dogs’ strengths and weaknesses, and compare them to the skills that human teams have been honing for years.
‘Delimitation’ is a crucial process during a weed eradication program, whereby the full extent of the invasion is mapped out. There’s really no other way of ensuring that your removal method is successfully targeting every last pesky plant. In 2011 the Hawkweed Eradication Project Control Group were wondering whether they’d nailed it. They’d been sending out search teams for years and had drawn a minimum convex polygon (MCP, dashed line mapped above) around the infestations they’d found. But could there be more hawkweed beyond those boundaries? The worst case scenario was that hawkweeds had actually spread much further south, where the terrain gets so tough that they’d probably have to give up on eradication entirely.
‘Further south’ encompasses a huge area, and the Control Group consulted Kate Giljohann and I to prioritise locations for search. While working on a biosecurity surveillance review for ACERA the previous year, I’d learned that very little research literature directly addresses how we should design delimitation surveys! So Kate and I started afresh, adapting my previous hawkweed survey design to increase the value of hawkweeds detected outside the known population boundary. This process also accounts for hawkweed occurrence (via dispersal and habitat suitability) and detection rates, ensuring that search teams visit places where they’re most likely to find far-reaching hawkweed infestations.
The hawkweed project managers used the shaded map we supplied (a above) to direct their GPS-tracked search teams (b above). The good news is that they found no new hawkweeds in the dreaded southern reaches, just a few extra plants to the north and east of the infestations they already knew about. While this was good evidence that they were close to delimitation, the search teams’ GPS practices were inconsistent – it was hard work for Kate and Michael Rigby to clean up the spatial data, and we had little idea how much time and effort the search teams had put in at each site.
In our new article, my co-authors and I document the process of designing, implementing and evaluating this delimitation survey. I’ve even put together a wishlist for future delimitation work. While minimum convex polygons describe infestations that we know about, probability maps can tell us where else our weed population might be lurking. The maps are ripe for Bayesian updating as we collect new survey data. They can also be aggregated into a delimitation score developed by Mark Burgman, Dane Panetta and colleagues to track progress from survey to survey.
Based on what my co-authors and I achieved in this study, I’m optimistic that these measures can be taken in real eradication programs.
Hauser, C.E., Giljohann, K.M., Rigby, M., Herbert, K., Curran, I., Pascoe, C., Williams, N.S.G., Cousens, R.D. & Moore, J.L. (in press) Practicable methods for delimiting a plant invasion. Diversity & Distributions. DOI: 10.1111/ddi.12388
The program funding my summer field project has been in the news this week! It’s a public introduction of Missy, the detector dog, and her trainer Steve Austin. With the help of several dozen government staff, researchers and volunteers, I’m evaluating Missy’s capacity to detect Hawkweeds in a variety of conditions.
Last month José and I ventured back to Wyperfeld National Park to explore monitoring options for the threatened pine-buloke woodlands. Here are a few of my photos taken along the way. Elsewhere, you can read more about…
Recently José, Guru and I returned to Wyperfeld National Park for the annual VMRG training weekend (you can read José’s account of our trip here and my summary of last year’s gathering here). It was great to reconnect with many familiar faces, receive updates on the monitoring program and get acquainted with the data logging devices.
We stuck around Wyperfeld for an extra 24 hours to get to know the park better in the context of our kangaroo-vegetation management project. We were privileged to have acting Ranger-in-Charge Dave Christian as our guide. He’s worked in the Mallee Parks for almost 30 years and I’d wager that what he doesn’t know about Wyperfeld and its management isn’t worth knowing! It was incredibly informative to ‘meet’ the buloke and slender Cypress pines that Parks Victoria are working to regenerate and to get a feel for the management operations on ground.
While I didn’t capture any photos of the Major Mitchell’s cockatoos or the regent parrots that we spotted, I’ve got plenty of other images to share.
I recently took a holiday in north Queensland and discovered some malleefowl-like incubator mounds in the rainforest!
They belong to orange footed scrubfowl, and we saw many of them scratching around in pairs near the Dubuji boardwalk at Cape Tribulation. I was surprised to hear from Mike D’Arcy that multiple pairs may work the same mound simultaneously. Though they are apparently quite territorial, these scrubfowl seem a good deal more sociable and less cryptic than the malleefowl I’m researching.
The Victorian malleefowl monitoring season is bookended by a volunteer training weekend and a reporting back weekend. The most recent reporting back session was held late in March in the town of Ouyen; José, Guru and I were able to head along for an update.
Malleefowl have generated some broader community interest this summer as they were seen in unprecedented numbers along the Ouyen-Patchewollock road, mostly likely attracted to a canola seed spill. On the weekend, the Victorian Malleefowl Recovery Group (VMRG) arranged a public information session where Dr Joe Benshemesh discussed the recent sightings, malleefowl behaviours and their conservation.
Ralph Patford and other VMRG members have been working hard over summer to arrange and erect malleefowl information signs at some of the more highly-frequented spots around the mallee. Parks Victoria Environment Program Manager for the Mallee Kathryn Schneider and VMRG chairman Peter Stokie had the honour of unveiling them.
For the remainder of the afternoon we packed into the Ouyen Harness Racing Club to review the season’s activities in more detail. 82 people contributed almost 1500 person hours’ work, monitoring 1300 mounds across Victoria’s north-west. Breeding numbers were very high this summer, although some observations indicate that birds may be concluding their breeding a little early and reworking their nests for the next season.
José and I made a short presentation to the VMRG, summarising the findings of the university workshop and explaining our upcoming plans for habitat suitability modelling and value of information analysis. The attendees made many helpful suggestions regarding the processes that they suspect most threaten malleefowl, and they aligned well with the models developed at the workshop.
Before retiring to the Victoria Hotel for dinner and a beer, Joe was kind enough to take us out to the Ouyen-Patchewollock road in the hope that we might see our first malleefowl. In fact, we saw our first 30 malleefowl that evening! Here are a few of them, captured on camera.
While meeting our first malleefowl will probably be our lasting memory of the weekend, it was really just as important to meet and learn more from the malleefowl’s many passionate supporters. I’m particularly grateful to Joe Benshemesh, Ross Macfarlane and Peter Stokie, without whom we would not have made it to Ouyen.
This month I’ve been getting acquainted with the Malleefowl Project. In Victoria, malleefowl monitoring is primarily run by the Victorian Malleefowl Recovery Group – that is, a community-based group of volunteers. Mike Bode, José Lahoz-Monfort, a couple of keen friends and I travelled out to Wyperfeld National Park for their annual training weekend on October 13-14.
The size of the group, the scale of their operations and the strength of their enthusiasm is really quite something. Over the summer, these volunteers visit hundreds of malleefowl mounds across Victoria (with little more than a slim chance of seeing the birds themselves!) to observe nest activity.
The main challenge is that sites are isolated and prone to extreme weather conditions – monitoring often requires camping for the weekend and walking between mounds on very hot days. The VRMG are equipped with satellite phones and strict safety procedures to ensure no-one gets lost. I can barely imagine how difficult this work must have been in the years before the group could access hand-held GPS!
Once at a mound volunteers collect a substantial set of data, prompted through each step by a very nifty custom-designed cybertracker application. These allow for thorough validation back in the office to identify recent malleefowl breeding activity, as well as other potential visitors to malleefowl mounds that might threaten successful hatching.
It was great to have a first look at the mallee environment and get to know some of the people driving malleefowl conservation in Victoria. They’ve developed an impressive data set over many years, and our team will try to put it to new and valuable use.