Resources and their distribution can influence social behaviour at translocation sites: lessons from a lizard

Author version made available in accordance with the Publisher's policy, after an embargo period of 24 months from the date of publication. © 2015. Licensed under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/In a translocation programme, social interactions among released individuals can influence the tendency for the individuals to remain at the site where they have been released. Dispersal away from the region of release may reduce the success of a translocation because dispersing individuals may move into less suitable habitat, or become separated from potential reproductive partners. In soft releases, where individuals are confined together for periods of time at the release site, before ultimate release, social interactions among the confined individuals may promote subsequent dispersal. In this study we investigated how variation in the abundance and distribution of a fundamental habitat resource, refuge burrows, influenced behaviour and possible subsequent dispersal of newly released individuals of the endangered Australian pygmy bluetongue lizard, Tiliqua adelaidensis, in simulations of translocation releases. Our aim was to determine if there was an optimal distribution of burrow resources that would minimise behaviours likely to lead to dispersal from the release site. There were more lizard movement around burrows 3.73 (SE 0.02) and fewer burrow changes 0.06 (SE 0.006) in low burrow densities than in high burrow densities (1.88 (SE0.02) movements; 0.50 (SE 0.008) burrow changes per day). When lizards were released in burrows near to each other (50 cm) they changed burrows more often (0.97 (SE 0.01)) and had more agonistic interactions (0.04 (SE 0.004)) than when released in burrows further apart (150 cm; 0.22 (SE 0.009) burrow changes; 0.003 (SE 0.001) agonistic interactions). These results suggest changes in behaviour can be induced by altering the way resources are distributed at a release site. We suggest that understanding the social organisation of any endangered species, and whether it can be manipulated, will be an important component of planning a translocation release programme.This research was supported by the Australian Research Council (LP0883495

Behavioural changes in an endangered grassland lizard resulting from simulated agricultural activities

Author version made available in accordance with the Publisher's policy, after an embargo period of 24 months from the date of publication. © 2015. Licensed under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Agricultural modification of landscapes profoundly affect the habitat of endemic species. Most Australian native grasslands have now been taken over for agriculture activities, which have dramatically changed these grassland ecosystems. Now only tiny fragments of the once more continuous native grasslands remain, and this has had a negative impact on species that occupy this habitat. One important question is how agricultural activities have altered the behaviours of endemic species in these fragmented habitats. One such species is the endangered scincid lizard, Tiliqua adelaidensis, which is endemic to native grasslands in South Australia. Current population sites of this species are grazed by domestic stock. We found simulated grazing led to lower body mass increases in the lizards, increased the time that lizards spent basking at their burrow entrance, reduced the tendency of lizards to move outside of their burrow, or to move to a different burrow, but increased the tendency of lizards to disperse away from the patch of habitat provided. Simulated ploughing of the surrounding habitat led to a reduction in dispersal rates. These results suggest that heavy grazing would have adverse impacts on existing populations of Tiliqua adelaidensis. They confirm that lizards avoid ploughed substrate, perhaps explaining previous observations of extremely low gene flow between adjacent populations

Visual conspecific cues will not help in pygmy bluetongue lizard translocations

Author version made available in accordance with the Publisher's policy, after an embargo period of 24 months from the date of publication. © 2015. Licensed under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Where a translocation program is used to reinforce an existing population of an endangered species, the response of the introduced individuals to cues from conspecific residents will have an important impact on the success of the translocation. If those cues induce the translocated individuals to stay at the release site the translocation is more likely to succeed than if the cues cause individuals to move away. We used conspecific models of the endangered Australian pygmy bluetongue lizard to identify behavioural parameters relevant to translocation success, that change when the visual conspecific cues are presented. Pygmy bluetongue lizards typically remain in or at the entrance of their refuge burrows. In the presence of conspecific models, introduced lizards significantly increased, and nearly doubled, the number of movements out of their burrows (mean (SE) number of movements with models = 0.44 (0.03); without models = 0.25 (0.03); P = 0.012) and more than doubled the number of movements away from the release area (mean (SE) number of movements with models = 0.28 (0.03); without models = 0.08 (0.02); P = 0.003), suggesting they would be less likely to remain within a resident population where they were released. We found that, by the end of the first day of experimental trials 11 of 16 lizards in treatments with models present had occupied burrows that did not have a model nearby, and that number increased to 14 of 16 lizards by the fourth day. The results suggest that cues from conspecifics will not encourage translocated lizards to stay at a release site."We would like to thank all of our sponsored in this project, which include Australian Research Council

Prey capture behaviour by pygmy bluetongue lizards with simulated grazing

Published version made available in accordance with the Publishers policy. This article is under an embargo for a period of three years from the date of publication

The impact of sheep grazing on burrows for pygmy bluetongue lizards and on burrow digging spiders

This is the peer reviewed version of the following article: [Clayton J, Bull CM (2015) The impact of sheep grazing on burrows for pygmy bluetongue lizards and on burrow digging spiders. Journal of Zoology, 297(1) pp. 44-53], which has been published in final form at DOI:10.1111/jzo.12247. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving (http://olabout.wiley.com/WileyCDA/Section/id-820227.html#terms). This article is under embargo for a period of 12 months from the date of publication.Grazing by domestic stock has altered and degraded natural grassland ecosystems worldwide, directly and indirectly impacting the endemic plant and animal species occupying those grasslands. The pygmy bluetongue lizard (Tiliqua adelaidensis) is an Endangered species, restricted now to fragments of native grassland habitat in South Australia, which are predominantly grazed by sheep. These lizards exclusively occupy burrows dug by spiders, and use them as refuges, basking sites and ambush points. They do not dig their own burrows and rely on co-existing spiders for this essential resource. We asked how sheep grazing influences construction and persistence of spider burrows, by comparing burrow dynamics in adjacent grazed and ungrazed grassland habitat. In ungrazed plots spider burrows increased over one spring and summer period, particularly after a summer rain event that softened the soil. In grazed plots more existing burrows were destroyed, presumably by sheep trampling, and fewer new burrows were constructed, leading to a net loss in burrow numbers over the same period. However, in this short study, grazing did not affect the number of pygmy bluetongue lizards or the number of lycosid spiders. Burrows that were lost tended to be shallower and to have smaller diameter entrances than those that were retained, suggesting that the best burrows for lizard refuges were more likely to persist despite sheep activity. However, heavy grazing may have negative impacts on both lizards and spiders, resulting from a reduction in available burrows and in spider digging behaviour

Determining the success of varying short-term confinement time during simulated translocations of the endangered pygmy bluetongue lizard (Tiliqua adelaidensis)

Author version made available in accordance with the publisher's policyTranslocation is a powerful tool in conservation management, but one of the major problems of this tool is dispersal after release because of a tendency of animals to disperse from unfamiliar sites. We assessed whether short-term confinement within enclosures at the translocation site can significantly decrease post release movement, if confinement allowed animals to become familiar with the new habitat, and to overcome handling related stress. We simulated the translocation of the endangered pygmy bluetongue lizard Tiliqua adelaidensis into the centre of a large enclosure and compared the behaviour between individuals confined to the central region for one or five days before release. We found that lizards confined for five days spent less time basking, and were more likely to disperse than lizards confined for just one day. We suggest that short-term confinement of lizards induces additional stress and that extra days of short-term confinement will not necessarily improve the success of a translocation

Artificial Water Point for Livestock Influences Spatial Ecology of a Native Lizard Species

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Pastoralism is a major agricultural activity in drier environments, and can directly and indirectly impact native species in those areas. We investigated how the supply of an artificial watering point to support grazing livestock affected movement and activity patterns of the Australian sleepy lizard (Tiliqua rugosa) during a drought year. We observed 23 adult lizards; six had access to a dam, whereas 17 lizards did not. Lizards with access to the dam had larger home ranges, were substantially active on more days (days with >100 steps), and moved more steps per day compared to lizards that did not have access to the dam, both during the early and late period of our observation. Furthermore, while the two groups of lizards had similar body condition early in the season, they differed later in the season. Lizards with dam access retained, whereas lizards without access lost body condition. Local heterogeneity in access to an artificial water resource resulted in spatially dependent behavioural variation among sleepy lizard individuals. This suggests that sleepy lizards have flexible responses to changing climatic conditions, depending on the availability of water. Furthermore, while reducing activity appears a suitable short term strategy, if harsh conditions persist, then access to dams could be of substantial benefit and could support sustained lizard activity and movement and allow maintenance of body condition. Hence, artificial watering points, such as the dams constructed by pastoralists, may provide local higher quality refugia for sleepy lizards and other species during drought conditions

Weight watching in burrows: variation in body condition in pygmy bluetongue lizards

Author version made available in accordance with the publisher's policyThe pygmy bluetongue lizard, Tiliqua adelaidensis, is an endangered scincid lizard which occurs in remnants of natural grasslands in the mid-north of South Australia. We assessed the factors affecting body condition of male and female lizards, using body size residuals as an index, over five sampling years. We included sex, phenotypic (patterned or plain morphs), temporal (sampling year and activity period within year), and climatic factors in our analyses. The results indicated that sampling year and activity period within the year were the two most important factors influencing variation in body condition of both male and female lizards over the period of the study. There were similar trends when we considered females separately in each of three stages of their reproductive cycle (pre-partum, gravid, post-partum). None of the analyses showed any significant effect of phenotype on body condition. Winter-spring rainfall was positively correlated with body condition of females in the pre-partum period, but showed no significant effect on mean body condition of any other grouping of adult lizards, nor a consistent direction of correlation among the different subsets of adult lizards that we considered. The substantial annual variations in the body condition of lizards, although of uncertain cause, provide important information for conservation managers who monitor persisting populations of this endangered species

Brain organization and retinal pathways in the sleepy lizard, Tiliqua rugosa

Brain structure and retinal pathways to the brain of the sleepy lizard Tiliqua rugosa were described, with this species identifiable as a type II lizard according to brain organisation. The retinal pathway appeared entirely crossed to the opposite side of the brain with termination of retinal fibres observed in the optic thalamus, pretectum, tectum and brainstem tegmentum

Pre-processing Techniques to Improve the Efficiency of Video Identification for the Pygmy Bluetongue Lizard

Copyright 2015 SCITEPRESS (Science and Technology Publications, Lda.). Published version of the paper reproduced here with permission from the publisherIn the study of the endangered Pygmy Bluetongue Lizard, non-invasive photographic identification is preferred to the current invasive methods which can be unreliable and cruel. As the lizard is an endangered species, there are restrictions on its handling. The lizard is also in constant motion and it is therefore difficult to capture a good still image for identification purposes. Hence video capture is preferred as a number of images of the lizard at various positions and qualities can be collected in just a few seconds from which the best image can be selected for identification. With a large number of individual lizards in the database, matching a video sequence of images against each database image for identification will render the process very computationally inefficient. Moreover, a large portion of those images are non-identifiable due to motion and optical blur and different body curvature to the reference database image. In this paper, we propose a number of pre-processing techniques for pre-selecting the best image out of the video image sequence for identification. Using our proposed pre-selection techniques, it has been shown that the computational efficiency can be significantly improved