Eyre%Bird%Observatory%% Reptile%Survey%Report%2013%

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Ronald Perry
5 years ago
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1 Eyre%Bird%Observatory%% Reptile%Survey%Report%2013% Donna%Simmons%&%Joe%Porter% Introduction During January 2013 a reptile surveying and identification course was run at the Eyre Bird Observatory, Western Australia. This course was run with two objectives: firstly to provide an accurate and up to date account of reptile species found in the area within the various vegetation types; and secondly to teach interested participants techniques for surveying, identifying and handling reptiles. The week was a great success with over 100 reptiles captured/observed from 16 different species. Participants had plenty of opportunity to handle and identify a variety of different species. Feedback from participants was very positive, with most vowing to return if the survey is to be repeated the following year. Survey Methods Pit-fall traps were used with each array consisting of 10 x 20 litre buckets arranged in an L-shape connected with a 30cm high aluminium fly wire drift fence (Figure 1). There were six arrays in total and three paired sites. Funnel traps were also used consisting of five at each site positioned against the drift fence. Traps were opened on the afternoon of the 21 st January, remained opened for four consecutive nights and closed on the afternoon of the 25 th of January. During this time several traps were closed due to ant invasions. Traps were intended to be set up for a total of 240 trap nights (60 buckets x 4 nights), however due to trap closures they were open for a total of 226 trap nights. Opportunistic sampling was also included in the survey records.

2 Figure 1: Pit-fall trapping array design with connecting drift-fall fencing Open pit-fall traps were maintained with a damp sponge, leaf litter and a Styrofoam tray placed inside each bucket. Funnel traps were covered with hessian bags. These steps were taken to prevent death or suffering of any trapped animals from dessication and provide some shelter. Traps were cleared between 6-10am each morning and again between 2-6pm. Each pit fall trap was cleared during each check with trapped reptiles removed, processed and released. Once checked, each trap was reset with a damp sponge, litter and tray and assessed for any other potential dangers such as ant invasion. Any trap deemed too dangerous was closed for the remainder of the survey. At the end of the survey funnel traps were removed, pit-fall traps were closed with the lids on and buried in sand and drift fencing was removed. Sites were chosen based on vegetation types to give an overview of the different reptile assemblages existing within the boundaries of the Eyre Bird Observatory. Sites were paired so three different vegetation types were surveyed. These included mallee

3 woodland, open grassland and mixed acacia scrub. Opportunistic captures were either attributed to the site they were caught at or caught within 50 metres of the homestead. Mallee woodland sites were areas dominated by mallee eucalypts. These areas typically had a thick cover of leaf litter, sparse understorey consisting mainly of shrubs and a canopy cover that exceeded 50% in most areas. Acacia scrub sites consisted predominantly of acacia shrubs with very few larger trees. Vegetation in this area is very thick with very little leaf litter on the ground. Open grassland areas were dominated by grass species with taller shrubs and trees mainly growing on the edges of these areas. Although the plants were growing quite close together, there was a lot of exposed bare sand with little cover. Results A total of 103 reptiles were trapped, including four re-traps, from 16 different species and seven families: Gekkonidae, Carphodactilidae, Diplodactylidae, Pygopodidae, Scincidae, Agamidae and Elapidae (Figure 2). The most commonly caught species was Morethia adelaidensis with 47 captures while Amphibolorus norrisi (mallee tree dragon), Cryptobletharus pulcher and Tiliqua rugosa (bobtail lizard), were each only caught once. Ctenophorus maculatus (spotted military dragon) was the next most commonly caught species at 15 captures. Some of the species were only caught/observed during opportunistic sampling and not in the traps. These included Underwoodisaurus milii (thick-tailed gecko), Cryptobletharus pulcher and Pseudonaja affinis (dugite). Aside from reptiles there was also one capture of Cercartetus concinnes, a pygmy possum.

4 50" 45" 40" Number'Trapped' 35" 30" 25" 20" 15" 10" 5" 0" Underwoodisaurus milii Diplodactylus calcicolus Christinus marmoratus Aprasia inaurita Cryptobletharus pulcher Ctenotus euclae Hemiergis initialis Lerista baynesi Lerista distinguenda Menetia greyii Morethia adelaidensis Tiliqua rugosa Amphibolurus norrisi Ctenophorus maculatus Pseudonaja affinis Reptile'Species' Figure 2: Total number of reptile captures during the pit-fall and funnel trapping at the Eyre Bird Observatory

5 The different vegetation types yielded different capture rates and species types. There was a total of 42 captures in the mallee woodlands from 10 species, 36 captures in open grassland from nine species and 14 captures in the acacia scrub from four species (Figure 3). Opportunistic sampling around the homestead found two species of gecko and one skink. The homestead captures are not included in the graph as the data is incomparable to the data collected at the other sites. This is due to the inconsistency of surveying and absence of pit-fall/funnel traps used in the area. 50" 45" 40" Number'captured' 35" 30" 25" 20" 15" Mallee" Acacia" Grass" 10" 5" 0" Christinus)marmoratus) Diplodactylus)calcicolus) Aprasia)inaurita) Cryptobletharus)pulcher) Ctenotus)euclae) Hemiergis)initialis) Lerista)baynesi) Lerista)distinguenda) Menetia)greyii) Morethia)adelaidensis) Tiliqua)rugosa) Amphibolurus)norrisi) Ctenophorus)maculatus) Reptile'Species' Figure 3: Total reptile captures at the three vegetation types: mallee woodland, acacia scrub and grassland.

6 Although capture rates and species composition varied between sites, there were also several species inhabiting two or more vegetation types. M. adelaidensis were trapped at all three vegetation types, C. maculatus and D. calcicolus were trapped in the acacia scrub and open grassland, while A. inaurita, C. euclae, L. bayensi, L. distinguenda and M. greyii were all trapped at the open grassland sites and mallee woodland sites (Figure 3). 15% 17% 39% Open Grassland; 36 Acacia Scrub; 14 Mallee Woodland; 42 39% Open Grassland; 9 Acacia Scrub; 4 Mallee Woodland; 10 A 46% B 44% Figure 4: Distribution of total captures by vegetation type of (A) total number of captures and (B) total number of species. Distributions of total number of reptiles captured and total number of species captured in each vegetation type were very similar (Figure 4). Mallee woodland yielded the greatest number of captures with 42 in total from 10 species. Open grassland sites recorded 36 captures from 9 species and acacia scrub had a total of 14 captures from 4 species. Sensor Camera Results Four sensor cameras were taken with us to the Eyre Bird Observatory and set up in various locations around the reserve. Memory cards were checked daily and cameras were set up over water points or where other tracks had been observed.

7 The majority of fauna captured consisted of the birds commonly seen around the homestead. These included Major Mitchells, ravens and brush bronzewings. Kangaroos were also often captured along with the occasional cat. Setting up the camera over a trap to catch a large skink seen on several occasions around the house proved useful with some images revealing it s identity as: Liopholis multiscutata (southern sand skink). Unfortunately we missed capturing the release of the pygmy possum on camera, most likely due to misjudging the camera angle. Discussion Due to the small number of captures yielded from this survey, it is difficult to draw any conclusions regarding the species recorded and habitat preference. A lot of the reptiles captured in this survey are found at various sites, suggesting that they may be habitat generalists, as opposed to specialists. All but two of the skinks were captured exclusively in mallee woodland or acacia scrub, with the exceptions being a bobtail found under some sheet tin near to the trap; and Morethia adelaidensis, a skink well known for living in a variety of different habitats. The different vegetation types had some very distinct habitat conditions that varied between each, which potentially determine the species of reptile inhabiting the area. Leaf litter is an important habitat attribute that can have a variety of impact on different species. Some species need leaf litter to survive. It can be used as shelter, some species will burrow into litter; hunting and food; insects and other reptiles live amongst the litter as well as food for the herbivores; and basking, reptiles can be very cryptic sitting on a substrate such as leaf litter and thus can hide well. L. distinguenda are known for using leaf litter, aswell as rocks and logs for shelter (Storr et al., 1999; Wilson & Swan, 2003). For other species a lack of leaf litter is more important. There are a number of fossorial species that forage and live beneath the ground in sandy substrates, for example L. baynesi and A. inaurita, whereas others dig burrows to provide their shelter (C. maculatus) (Storr et al., 1999; Wilson & Swan, 2003). Although basking on sand would expose the reptile to potential predators, the

8 warmth of the sand and sun provide the reptile with a great opportunity to warm its body quickly, while basking next to shelter can ensure a quick escape or shade from the heat. Canopy cover is also a very important habitat attribute especially since reptiles often require the sun and the shade to control their body temperature effectively. In an area with a thick canopy cover, reptiles may need to take advantage of warm substrates and the little sun they do get to heat their bodies, ie. a warm rock in the sun. For areas with little canopy cover, the opposite may be true, that it is harder to find a place to cool down. Burrowing into the sand or using the vegetation available are effective ways to find the shelter. Vegetation and vegetation type is an obvious difference between the sites that can have a great impact on the type of reptiles you may find in the areas. Vegetation can be used for shelter, food sourcing, basking and more. Some reptiles live in trees such as C. marmoratus (marbled gecko), which are known to shelter under bark during the day. Other species may use the thinner branches of trees to bask on. A. norrisi are often found perched on fallen branches (Wilson & Swan, 2003). The open grassland site had little vegetation for supporting basking reptiles, however many C. maculatus were seen escaping to their burrows at the base of the grasses when disturbed. Although the survey was successful overall, there are a number of improvements that can be made, and will be implemented for the next survey to come. During the survey we struggled with ant invasions, which resulted in death for a few of our trapped reptiles. Unfortunately we were not prepared for this and did not bring any ant repellent out to the observatory with us. We compensated for this by closing any buckets deemed too high a risk, resulting in a high number of closures during the week. With some ant repellent, we may be able to keep more buckets open and collect more data at the survey sites.

9 This survey comprised of three paired sites and three vegetation types. For the next survey we would like to extend this to five paired sites with five vegetation types. One such vegetation type that we would like to include would be the melaleuca woodland. Having a greater range of vegetation types will give us more information regarding the guilds of reptiles that exist at the Eyre Bird Observatory and potentially a greater variety of species to capture. Although a general site assessment was carried out to determine appropriateness as a survey site, it would be beneficial to carry out more detailed vegetation surveys. This will include assessing habitat characteristics, such as canopy cover, litter density, vegetation density and height etc, which may be correlated to the species captured in the area. Conclusion Overall this survey week was a great success. Participants learnt a lot about reptile surveying and identification, and everyone participated in all activities enthusiastically. The Eyre Bird Observatory is a fabulous setting for such a course and this course is a great opportunity to learn about a variety of reptile species and the habitats they live in. References Storr, G.M., Smith, L.A. & Johnstone R.E. (1999) Lizards of Western Australia. I Skinks, Western Australian Museum, Perth Wilson, S. & Swan, G. (2003), A Complete Guide to Reptiles of Australia, New Holland Publishers (Australia) Pty Ltd, Sydney

Acknowledgements This course was a success because of the people that were involved to help run it. The caretakers, Joyce and Bob, provided us with amazing food, hospitality, advice and conversation.

10 Acknowledgements This course was a success because of the people that were involved to help run it. The caretakers, Joyce and Bob, provided us with amazing food, hospitality, advice and conversation. The participants were enthusiastic and some had extensive knowledge already, so were a very easy bunch to get along with, making the survey very enjoyable. Last but not least my co-pilot, Joe Porter, who kept me on track and gave me the push I needed to organise this survey. The team Back row: Darrell, Joyce, Chris, Joe; Front row: Bob, Lynsey, John, Donna "

Active Searching: As a fauna survey technique.

Active Searching: As a fauna survey technique. Active searching: searching or foraging by hand for fauna in places where animals are likely to be sheltering. for reptiles, frogs, invertebrates (consig