Surveying for arboreal mammals in the Grampians National Park and adjacent reserves: Fauna Survey Group Contribution No. 28.
The Fauna Survey Group (FSG) of the Field Naturalists Club of Victoria (FNCV) carries out fauna surveys on private and public land in accordance with its Department of Environment, Land, Water and Planning research permit. The group has carried out over 700 surveys since 1972, with many of these being on land managed by Parks Victoria (PV). More recently the group has been working with PV to identify projects which fit with the priorities, interests and resources of both organisations.
One of the projects identified was to increase the knowledge of arboreal mammal presence, in this case in the reserves in and around the Grampians National Park (NP). In particular the survey attempted to find evidence of the endangered Squirrel Glider Petaurus norfolcensis, which has been recorded previously in this area (Menkhorst et al. 1988).
As a group, Victorian arboreal mammals are well-represented in the conservation rating systems. Their conservation status is outlined in Advisory List of Threatened Vertebrate Fauna in Victoria (DSE 2013). Red-tailed Phascogale Phascogale calura is considered regionally extinct, Leadbeater's Possum Gymnobelideus lead-beateri, Squirrel Glider and Spot-tailed Quoll Dasyurus maculatus are endangered and Brush-tailed Phascogale Phascogale tapoatafa and Greater Glider Petauroides volans are vulnerable. All these species are listed under the Flora and Fauna Guarantee Act 1988 (FFG).
Other arboreal species, Eastern Pygmy Possum Cercartetus nanus and Little Pygmy Possum Cercartetus lepidus, are listed as near threatened on the Advisory List but not listed under the FFG.
The Grampians NP is located in western Victoria, 250 km from Melbourne, and is the fourth largest national park in the state with an area just over 167 000 ha (Parks Victoria 2003). As well as the national park itself, Parks Victoria is also responsible for managing smaller reserves in the area. The area has been described as one of the strongholds for the Squirrel Glider in Victoria (Menkhorst et al. 1988).
The project aimed to ascertain the presence of the endangered Squirrel Glider at sites with historical records and to provide species lists of other nocturnal, arboreal fauna in poorly-surveyed areas.
The survey took place between 6 June and 20 June 2014 in five study sites (Fig. 1). These sites were chosen because the Squirrel Gliders had been recorded or were suspected to occur there.
Silverband Falls and Heatherlie are within the Grampians NP. Heatherlie is approximately 13 km north of the township of Halls Gap (37.1167[degrees] S, 142.5500[degrees] E) and is a new acquisition to the PV estate. Silverband Falls are located approximately seven kilometres south of Halls Gap. Deep Lead Flora and Fauna Reserve, Lonsdale Nature Conservation Reserve (NCR) and Ledcourt State Forest are respectively 23 km north-east, 16 km north-north-east and 15 km north of Halls Gap.
At each site, transects were designated by Parks Victoria, 13 in total. Most of the transects were around one kilometre in length, depending on tracks and access. The Silverband transect was four km long, as this was the distance between safe parking locations.
The Silverband transect was the road between the Rosea car park and the Silverband Falls car park. This transect was quite steep and heavily wooded. All the other transects were predominantly in flat and open woodland. All these, except for one transect in Heatherlie, were open Eucalypt woodland with relatively little understorey. The Heatherlie transect was denser, containing groves of Silver Banksia Banksia marginata.
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The survey design allowed for one camera and one hair tube per transect km (approx.). Each transect was to be spotlighted. The exceptions were Deep Lead, where two additional cameras were deployed because no cross-country spotlighting was possible (for safety reasons due to abandoned mineshafts), and Silverband where no cameras or hair funnels were placed.
The spotlighting and the deployment of the cameras and hair funnels took place between 6 and 8 June 2014. The cameras and hair funnels were retrieved on 19 and 20 June 2014, being in the field for 13 to 14 days.
Seventeen cameras were deployed for a total of 216 camera-nights. Sixteen cameras were Ltl Acorn Ltl6210M and the other a Scoutguard 550V.
Fifteen of the cameras (including the Scout-guard) were deployed in eucalypt trees within each transect, at a height genera y between three and four metres. Mature hollow-bearing trees were used if available. All these cameras, except one, were placed on modified CCTV camera housing brackets (Drury 2014). The other was strapped directly to the tree. All were baited with peanut butter, oats and golden syrup. Nine of the cameras had bait in tea infusers, where the bait was inaccessible, and the other six had bait in an 80 mm piece of 20 mm conduit, with the bait accessible at both ends.
The other two cameras were deployed at Heatherlie in flowering Banksia trees, focusing on a tea infuser containing bait. The Banksia florescences may well have been an additional attractant.
All cameras were placed vertically, with the detection beam perpendicular to the trunk and parallel to the ground. They were set to video for 20 seconds and one second between shots. The sensitivity level was high and they were set to operate between 1600 hours and 0900 hours. The side PIR (early warning system) was set to 'on' for the Ltl Acorn. This facility is not available in the Scoutguard.
The results were analysed for species presence and the attitude of the animal to the bait (i.e. did the animal appear to show any interest?). The 25 hair funnels were all the 150 mm models from Faunatech. All were baited with peanut butter, oats and golden syrup. Fourteen of them were placed in trees near the cameras deployed on the CCTV brackets. They were screwed to the branch with the opening facing downwards. The other eleven were pegged out on the ground, in Heatherlie, in two banks of five and a single tube. The number of trap-nights totalled 309. Hair funnels were retrieved at the same time as the cameras and the hairs were analysed by Hans Brunner. Brush-tailed Phascogale Phascogale tapoatafa results were confirmed by Barbara Triggs.
All transects had one spotlight survey, with teams varying from four to seven people. The time taken varied from 25 to 120 minutes.
The overall survey effort is summarised in Table 1.
Eight species of arboreal mammal were detected during the survey (Table 2). One, the Eastern Pygmy Possum, was identified using its distribution to assist in identification.
The success of each survey method at each location is detailed in Table 3.
Table 4 shows the days in the camera cycle (all cameras combined) where the different arboreal mammal species appeared. The results show that 60% of the images were captured in the second week. Excluding the Common Brush-tail Possum, the percentage jumps to 73%.
Different approaches to measuring the results are contained in Table 5. Sixty-one arboreal mammal images were recorded. It has been assumed that images of the same species cluster around the same time, they are part of the same 'event'. An 'event' is an attempt to define the maximum likely number of individuals whose images have been recorded. It has been assumed that if the images of the same species are less than 5 minutes apart that they are in the same event. There were 31 such events.
In 14 of the events the animal was shown to have a definite interest in the bait (i.e. they nosed around it). Of the 14 positive event responses to the bait, nine were for tea infusers and five were for conduits.
Individual cameras recorded animal images on between zero and five nights, with an average of 1.5 nights per camera. One camera recorded three arboreal mammal species, one recorded two, nine recorded one and six recorded none.
All the survey techniques yielded results. The survey demonstrated the value of multiple survey approaches, as each technique detected a species not provided by the others. Spotlighting uniquely detected the Common Ringtail Possum and Eastern Pygmy Possum, the hair funnels detected Brush-tailed Phascogale and the cameras detected Feathertail Glider, Sugar Glider, Squirrel Glider and Yellow-footed Antechinus.
A relatively short and low-cost effort detected the presence of eight species of arboreal mammal over the five study areas.
The Squirrel Glider record from the newly-acquired Heatherlie section of the Grampians NP is significant as, according to the Victorian
Biodiversity Atlas (VBA), this endangered species has not been recorded in the Park since July 1984. The Grampians represent the most south-westerly population of this species in all of Australia. This population is isolated from other Squirrel Glider strongholds (Fig. 2a) and requires careful management and monitoring.
The Brush-tailed Phascogale records are also significant as this species has not been previously recorded from Lonsdale NCR nor the immediate Grampians NP area according to the VBA database (Fig. 2b). This species has suffered a large range decline in south-western Victoria (Menkhorst 1996).
These results, plus previous research (Menkhorst et al. 1988), mean that the Heatherlie and Lonsdale reserves could play an important role in the conservation of two FFG-listed species. Effective management will require, amongst other things, a good understanding of the population distribution.
The question remains as to whether the three techniques used in this study are the most appropriate for ascertaining arboreal mammal presence. Each of the techniques we used has its strengths or weaknesses.
The use of spotlights for surveying for arboreal mammals has become standard (Catling et al. 1997). However, even reasonable-sized animals such as Squirrel Glider (Menkhorst et al. 1988) and Brush-tailed Phascogale (Soderquist et al. 1996) are considered to be difficult to spotlight. The surveyor has to be in the right place at the right time and the animal has to present itself (e.g. look at the light so that eye-shine is detectable). Our experience is that smaller mammals, such as Feather-tailed Gliders and Pygmy Possums, are also easy to miss and difficult to identify. Results may be improved by using thermal imaging to augment the spotlighting. It has proved to be a successful adjunct in other studies (Focardi et al. 2001; Edwards et al. 2003), although mainly for larger animals.
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We found that it was possible to detect Brush-tailed Phascogales by using hair funnels. The technique has also been used successfully to detect gliders, at least to the genus level (van der Ree et al. 2004). This method has been shown to be not as effective as other methods (Paull et al. 2012), but is cost effective and has shown the propensity to detect species not detected by other methods (Garden et al. 2007). There is a need for specialist knowledge for hair analysis and the process can be difficult and open to mistakes (Garden et al. 2007). Soderquist et al. (1996) suggested that the use of hair funnels is simple and non-invasive and we also found this to be the case. However, while we found only hair in our funnels, other studies (e.g. Mills et al. 2002) have found that fauna such as small lizards, frogs and birds can be trapped by this equipment. Care needs to be taken in reducing this 'by-catch', for example ensuring the floor of the funnel or tube is free of sticky material (Eyre et al. 2014).
Camera trapping is now used widely in wildlife management. It has been shown to provide basic knowledge of the distribution of animals, is relatively inexpensive and relatively non-invasive and safe both for humans and animals (Swann and Perkins 2014). Our survey showed good results for Sugar Glider and Common Brushtail Possum and some possibilities for Antechinus, Feathertail Glider and Squirrel Glider.
Meek et al. (2015) suggest that the constraints and limitations of cameras are not always considered. They identified a number including the camera model, the camera detection system, camera placement and orientation, triggering and recovery, camera trap settings, temperature differentials, species identification and behavioural responses of the animals to the cameras.
Our results may assist through the following observations:
* We found that the second week was the most productive, so the results from shorter term deployments may be misleading.
* Only the Common Brushtail Possum showed a preference for access to the bait (i.e. the conduit).
* The detection of the Squirrel Glider, Feathertail Glider and Pygmy Possum in Silver Banksia suggests that camera deployment in food-producing trees may be rewarding. The attraction of Squirrel Gliders to nectar and pollen is noted in Quin (1995) and Holland et al. (2007). However, the latter found this to be a small part of their diet.
Other techniques such as stagwatching, predator scat analysis, trapping and nestboxes may also contribute to the ultimate detection regime for this suite of animals. All have their strengths and weaknesses.
Stagwatching has limited application for less common species such as Brush-tailed Phascogale because of the difficulty in predicting where the animals will be, given a multitude of nesting hollows and the animals' propensity to move around (Soderquist et al. 1996).
Predator scat analysis has proved successful in establishing species within a particular area. In a survey in north-east Victoria (Brunner et al. 1976), the hairs of four species of glider, four species of possum and one pygmy possum were detected in the scats of Red Fox Vulpes vulpes and feral dog Canis familiaris. Fox scats can be collected along tracks (Brunner et al. 1976, Friend 1978), which are readily available in most of the study area. Friend (1978) suggests detection of animals by a predator is more efficient than relying on a research worker. Hairs collected this way also avoid the by-catch issue associated with hair funnels.
Trapping has proved successful, but is labour-intensive (Garden et al. 2007) and can cause stress and injury to the animals (Soderquist et al. 1996; Menkhorst et al. 1988). The Brushtailed Phascogale has also been found to be trap-shy (Soderquist et al. 1996).
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The use of artificial nestboxes has proved to be successful in providing habitat for arboreal mammals, and contributes to their management and conservation (Beyer and Goldingay 2006). Soderquist et al. (1996) consider nestboxes as a preferred option for surveying for Brush-tailed Phascogale. Artificial habitat has been used in studying Feathertail Gliders (Fleming and Frey 1984). The nestbox method does not require handling of the animals, although if such handling is needed for the research, the animals are readily obtained (with the necessary permits). In the FNCV nestbox program in the Graytown area in central Victoria, both Brush-tailed Phascogale (Fig. 3) and Squirrel Glider (Fig. 4) have been recorded in nestboxes, as has the Sugar Glider.
Our small survey, and other FSG work, suggests that the use of spotlighting, cameras, nestboxes and hair funnels could form the basis of an effective, minimally invasive and relatively inexpensive method for monitoring arboreal mammals. These techniques are relatively simple and can be implemented with the support of volunteer organisations. Further work will be needed to ascertain the most productive deployment regime, which may vary for individual species.
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Thanks to members of Fauna Survey Group for their field work: Peter and Su Dempsey, Lee Dennis, Cath Drury, Linda and Ray Gibson, Peter Homan, Knud Hansen, Mia Lang, Graeme Patterson, Russell Thompson and Paul Webb. Thanks also to Mark Antos, Ryan Duffy and Dave Handscombe from Parks Victoria for their support, guidance and hospitality. Thanks also to Mark for his comments on the manuscript, and provision of the maps. Thanks to Hans Brunner and Barbara Triggs for their work on the hair analysis.
The survey was carried out in accordance with Department of Environment and Primary Industries research permit 10006308 and Wildlife and Small Institutions Animal Ethics Committee approval 12.12.
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Received 5 August 2015; accepted 25 February 2016
Fauna Survey Group, Field Naturalists Club of Victoria, PO Box 13 Blackburn, Victoria 3130
Table 1. Grampians survey effort. Survey site Number of Transects Cameras transects spotlighted (Bait only) Deep Lead 3 5 Heatherlie 3 3 4 Ledcourt 3 3 3 Lonsdale 3 3 3 Silverband 1 1 Total 13 10 15 Survey site Cameras Hair Hair (Banksia funnels funnels and bait) (tree) (ground) Deep Lead 5 Heatherlie 2 3 11 Ledcourt 3 Lonsdale 3 Silverband Total 2 14 11 Table 2. Arboreal species detected by all survey methods, and the number of sites and transects in which they were recorded. Species Number of Number of study site transect appearances appearances (n=5) (n=13) Brush-tailed Phascogale Phascogale 2 2 tapoatafa Common Brushtail Possum Trichosurus 4 11 vulpecula Common Ringtail Possum Pseudocheirus 1 1 peregrinus Feathertail Glider Acrobates pygmaeus 1 1 Eastern Pygmy Possum Cercartetus nanus 1 1 Sugar Glider Petaurus breviceps 2 4 Squirrel Glider Petaurus norfolcensis 1 1 Yellow-footed Antechinus Antechinus 1 1 flavipes Table 3. Arboreal mammal results by survey area and survey method. Survey Area Camera Camera Hair Funnel (Eucalypt) (Banksia) (tree) Deep Lead Common Brushtail NA Nil Possum Sugar Glider Heatherlie Common Brushtail Common Brushtail Nil Possum Possum Sugar Glider Feathertail Glider Squirrel Glider Ledcourt Yellow-footed NA Nil Antechinus Common Brushtail Possum Lonsdale Common Brushtail NA Brush-tailed Possum Phascogale Silverband NA NA NA Survey Area Hair Funnel Spotlighting (ground) Deep Lead NA NA Heatherlie Brush-tailed Common Brushtail Phascogale Possum Eastern Pygmy Possum Ledcourt NA Common Brushtail Possum Lonsdale NA Common Brushtail Possum Silverband NA Common Brushtail Possum Common Ringtail Possum Table 4. The arboreal mammal species whose images were captured and the days on which this occurred. Species Day/s Common Brushtail Possum 1, 2, 4, 5, 6, 7, 8, 12, 13 Feathertail Glider 3,9 Squirrel Glider 8, 10 Sugar Glider 2, 9, 10, 11, 12, 13 Yellow-footed Antechinus 9 Table 5. Number of images, events and their noticeable response to the bait in these events, Species Images Events No. of events with positive interest to bait (tea infuser, conduit) Common Brushtail Possum 44 18 6 (2, 4) Feathertail Glider 2 2 0 Squirrel Glider 4 2 1 (1, 0) Sugar Glider 10 8 6 (5, 1) Yellow-footed Antechinus 1 1 1 (1, 0) Total 61 31 14 (9, 5)
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|Publication:||The Victorian Naturalist|
|Date:||Jun 1, 2016|
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