Wednesday, February 21, 2024

Koala conservation in Queensland – interview with Australian Wildlife Conservancy

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This article relates to ongoing debates on Australian Rural & Regional News: Open for Debate – Koalas; Open for Debate – Bushfires, Logging, Burns & Forest Management

Australian Wildlife Conservancy recently secured federal funding to assist in a three-part Koala conservation project at Curramore and Mount Zero-Taravale Wildlife Sanctuaries in Queensland.

Australia Rural & Regional News asked some questions about the koala conservation projects and monitoring, and land and fire management of Andrew Howe, Australian Wildlife Conservancy Senior Field Ecologist and Peter Stanton, Australian Wildlife Conservancy Senior Ecologist.

Koala
Pictured is a Koala at Mount Zero-Taravale Wildlife Sanctuary where there have been occasional incidental sightings of the species. Photo: AWC.

ARR.News: Is there now an overemphasis on koalas and koala habitat over sustainable land management and other fauna and flora generally?

Andrew Howe, AWC: No, koalas are iconic and endangered. In the northern extent of their range, around Australian Wildlife Conservancy’s Mount Zero-Taravale property, very little is known about their ecology, distribution and threats. Further, koalas act as an umbrella species (by conserving koalas, we conserve other fauna and flora). 

ARR.News: Curramore itself, at 196 hectares, is a small area in terms of koala ranges – given the range of a single koala is, is it 100ha? – and could only sustain a couple of koalas at most. Is this so? Why focus on Curramore?

Andrew Howe, AWC: Curramore Wildlife Sanctuary is the largest nature refuge on the Sunshine Coast. Although considered small compared to other Australian Wildlife Conservancy sanctuaries, it is a geographically significant habitat corridor linking habitat from Maleny National Park in the west to other nature refuges and koala habitat in the east.

On a previous koala monitoring project I worked on in SE Qld, koala home ranges averaged 26ha for males and 12ha for females, so Curramore could potentially sustain an important koala population in the context of the broader region. Our upcoming koala monitoring program will aim to determine the population density of koalas on Curramore.  

ARR.News: Numbers of koalas at Curramore. Has monitoring been done to establish koala numbers in Curramore and adjoining areas previously? Over what time period?  Is there evidence that koala numbers at Curramore and adjoining areas have altered over 5, 10, 20 or more years?

Andrew Howe, AWC: Australian Wildlife Conservancy has surveyed for koalas on Curramore in the past through the use of spotlighting transects and using conservation detection dogs to sniff out fresh koala scat and the scent of animals up trees. These survey methods are not ideal as much of the property is steep and not easily assessable.

In 2021, spotlighting transects counted four individual koalas in a relatively small area. Detection dog surveys have also detected an increase of koala activity on the property from 2015 to 2022. Koala populations in SE Qld and the Sunshine Coast hinterland are representative of the decline across most of their range in Qld and NSW. Ongoing threats include habitat degradation and fragmentation, dog attack, disease and car strike.

ARR.News: Wouldn’t it be more useful to monitor for koalas in, not just Curramore, but the adjoining areas?

Andrew Howe, AWC: We are doing this. There are many koala monitoring projects across SE QLD and Curramore is a site that researchers from the Sunshine Coast University are looking at as a long-term study site to monitor the koala population over time. These researchers have many sites across the region.

ARR.News: Will the Mount Zero monitoring be establishing a baseline only?

Andrew Howe, AWC: The Mount Zero-Taravale monitoring will form the baseline for koala population estimates on the property. We plan to undertake ongoing monitoring as part of Australian Wildlife Conservancy’s EcoHealth program. Under the program we perform monitoring of threatened species including koalas every 2-5 years to determine if the populations are stable, increasing or decreasing. If the population is decreasing, we will then undertake specific targeted research to determine what is driving the decline and then mitigate threats where possible.

ARR.News: Is the bioacoustics technology to monitor koalas similar to that used by Dr Brad Law and DPIE NSW?

Andrew Howe, AWC: Yes, we will use bioacoustics to monitor koalas at both Curramore and Mount Zero-Taravale.

ARR.News: How exactly will the Curramore monitoring compare the effectiveness of thermal drone and acoustics technology?

Andrew Howe, AWC: We will compare estimates that are derived from the two techniques. Curramore is small enough that we can trial using thermal drone technology and compare the number of individuals spotted with the number of koalas detected on the acoustic recorders. We are looking at the effectiveness of each technique in relation to output of data, certainty of results and resources needed including funding.

ARR.News: How effective has the AWC found thermal drone and acoustics technology for monitoring (for any creature) so far?  Are there strengths and weaknesses of each?

Andrew Howe, AWC: Australian Wildlife Conservancy has used thermal technology across some of our sanctuaries and have had some success. This includes increasing our detections of arboreal mammals in the Kimberley region of WA. We have also trialled thermal scopes for arboreal mammals in the wet tropics and compared the results with that of traditional methods such as spotlighting.

Bioacoustic monitoring is a relatively new tool and will increasingly be utilised across Australian Wildlife Conservancy sanctuaries. In the north-east region AWC is using bioacoustics to survey for microbats at Mount Zero-Taravale and Curramore, and with the Magnificent Broodfrog at Mount Zero-Taravale. Acoustic recorders are useful to monitor cryptic species that vocalise during the breeding season (frogs), that vocalise at non-opportune times (at night) and can be left out in the field for extended periods of time.

ARR.News: How reliable does AWC believe scat monitoring is for determining the numbers of koalas in an area at one time?

Andrew Howe, AWC: Scat monitoring is another useful technique but, at this stage, will not be utilised at Curramore or Mount Zero-Taravale. Given Curramore is relatively inaccessible, we have more reliable monitoring techniques to survey koalas. In addition, given the size of Mount Zero-Taravale and limited knowledge as to where the koalas are on the sanctuary, detection dogs is not a useful technique.

ARR.News: Will AWC being using (mild?) burning to clear lantana or otherwise improve the country at Curramore and Mount Zero?

Peter Stanton, AWC: When Australian Wildlife Conservancy purchased Curramore in 2005, it was mostly dense lantana interspersed with patches of sparse kangaroo grass. Following a period of about 18 months, work took place on two days most weeks to eradicate the lantana by spraying or cutting and poisoning the stumps. Eventually, when a more vigorous ground cover of grass had developed, a dry period in July was used to burn the area in an attempt to eradicate what remained of the lantana, mostly on steep lower slopes. This was very successful and what lantana resprouted was easily dealt with. The fire caused limited canopy scorch and an extremely vigorous ground cover of kangaroo grass soon developed. A few months after the fire the first koalas were seen. Other managed fires have followed to maintain the ground cover. 

From this exercise, we have learned that:

  • It seems likely that koalas prefer forests or woodlands unimpeded by dense understory of shrubs or lantana;
  • To maintain such conditions the development of a vigorous ground cover that is managed with regular burning is essential;
  • Regular burning of a grassy ground cover is ideally at intervals of two to three years, but longer intervals can be used if the ground cover remains vigorous, and weather conditions at the time of burn are chosen to ensure that no significant canopy scorch occurs;
  • Koalas are unlikely to suffer much discomfort from fires that do not cause significant canopy scorch.

In relation to Mount Zero-Taravale Wildlife Sanctuary, management with a series of fires has been successful in greatly reducing the area of dense lantana infestations in eucalypt woodland. However, as all of the rare koala sightings, as far as I am aware, have been in grassy woodlands with no invasive lantana, such management is unlikely to have been of relevance to the maintenance of the present koala populations. There is, of course, the possibility that we have created new habitat for them to occupy. As for Curramore their continued existence would depend on the absence of widespread crown scorching fires. Our management of the sanctuary with widespread regular patch burning to avoid the development of heavy fuel accumulations, has been successful in achieving that.

ARR.News: If burning is used, what is Australian Wildlife Conservancy’s view on what burning and when it is suitable for maintaining/ improving the country and when it should be avoided?

Peter Stanton, AWC: Fire management is a critical part of Australian Wildlife Conservancy’s practical approach to conservation. Restoring ecologically appropriate fire regimes is the primary objective of fire management on Australian Wildlife Conservancy sanctuaries.

In northern Australia fire patterns are strongly influenced by the prevailing monsoonal climate – characterised by a dramatic high-rainfall ‘wet season’ (November–February) followed by a low-rainfall ‘dry season’ over the winter months. The wet season drives rapid growth in the grassy understorey, which subsequently cures, leading to high fuel loads heading into the dry season. The early dry season is therefore a critical time for managing fire in northern Australian savannah ecosystems.

Australian Wildlife Conservany’s land managers start implementing prescribed burns when conditions allow at the end of the wet season (typically March-May). Prescribed burning involves a range of techniques: matches, drip torches, and aerial incendiaries are used to ignite fires according to a strategic annual burn plan. Prescribed burning in the early dry season is implemented in part to limit the spread of the more destructive wildfires that occur in the later part of the year.

Related story: Federal grant to fund koala conservation in Queensland: AWC

This article relates to ongoing debates on Australian Rural & Regional News: Open for Debate – Koalas; Open for Debate – Bushfires, Logging, Burns & Forest Management

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