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Ecology, management and conservation in natural and modified habitats
RESEARCH ARTICLE

Maximising trapping efficiency in reptile surveys: the role of seasonality, weather conditions and moon phase on capture success

Lisa M. Spence-Bailey A C , Dale G. Nimmo B , Luke T. Kelly B , Andrew F. Bennett B and Michael F. Clarke A
+ Author Affiliations
- Author Affiliations

A Department of Zoology, La Trobe University, Bundoora, Vic. 3086, Australia.

B School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Vic. 3125, Australia.

C Corresponding author. Email: lm4spencebailey@students.latrobe.edu.au

Wildlife Research 37(2) 104-115 https://doi.org/10.1071/WR09157
Submitted: 16 November 2009  Accepted: 5 February 2010   Published: 16 April 2010

Abstract

Context. Designing an appropriate survey protocol requires understanding of how capture rates of target species may be influenced by factors other than on-ground abundance, such as weather conditions or seasonality. This is particularly relevant for ectotherms such as reptiles, as activity can be affected by environmental conditions such as ambient temperature.

Aims. The present study examines factors affecting capture success of reptiles in semi-arid environments of southern Australia, and addresses the following two main questions: (1) what is the influence of weather and seasonal factors on capture rates of reptiles, and (2) what are the implications for developing an effective protocol for reptile surveys?

Methods. We surveyed reptiles using pitfall traps in spring and summer of 2006/07 and 2007/08 at sites (n = 280) throughout the Murray Mallee region of south-eastern Australia. We used mixed-effect regression models to investigate the influence of seasonal and weather-related variables on species’ capture success.

Key results. Total captures of reptiles, and the likelihood of capture of 15 reptile species, increased with rising daily temperature. Greater numbers of individual species were captured during spring than in summer, even though temperatures were cooler. This probably reflects greater levels of activity associated with breeding. Several species were more likely to be captured when maximum or minimum daily temperatures exceeded a certain level (e.g. Lerista labialis, Delma australis, Nephrurus levis). Other factors, such as rainfall and moon phase, also influenced capture success of some species.

Conclusions. Surveys for reptiles in semi-arid environments are likely to capture the greatest diversity of species on warm days in late spring months, although surveys on hot days in summer will enhance detection of particular species (e.g. Morethia boulengeri, Varanus gouldii). We recommend trapping during periods with maximum temperatures exceeding 25–30°C and minimum overnight temperatures of 15°C. Finally, trapping during rainfall and full-moon events will maximise chances of encountering species sensitive to these variables (blind snakes and geckoes).

Implications. Selecting the most favourable seasonal and weather conditions will help ensure that reptile surveys maximise the likelihood of capturing the greatest diversity of reptiles, while minimising trap-effort required.


Acknowledgements

Funding and logistical support for the Mallee Fire and Biodiversity Project was provided by Land and Water Australia, the Mallee Catchment Management Authority, Parks Victoria, Department of Sustainability and Environment Victoria, Department of Environment and Heritage SA, Lower Murray–Darling Catchment Management Authority, Department of Environment and Climate Change NSW, Australian Wildlife Conservancy and Birds Australia. We particularly thank Greg Holland for statistical guidance, Angie Haslem for designing the study area map and Parissa Kamali from the Bureau of Meteorology, Melbourne, for assistance in obtaining climate records. Many thanks go to other members of the Mallee Fire and Biodiversity Team (Sarah Avitabile, Rick Taylor, Simon Watson, Sally Kenny and Kate Callister) for ongoing technical and moral support and especially to our technical assistant Lauren Brown and the many volunteers who assisted with the field work. This study was carried out with approval from Animal Ethics Committees at La Trobe University (Approval No. AEC06/07(L)V2) and Deakin University (Approval No. A41/2006), and permits from the Department of Sustainability and Environment, Victoria (Permit No. 10003791), the Department of Environment and Heritage, South Australia (Permit No. 13/2006) and the National Parks and Wildlife Service, NSW (Licence No. S12030).


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