Effects of trap position, trap history, microhabitat and season on capture probabilities of small mammals in a wet eucalypt forest
R. B. Cunningham A , D. B. Lindenmayer A D , C. MacGregor A , S. Barry B and A. Welsh CA Centre for Resource and Environmental Studies, The Australian National University, Canberra, ACT 2000, Australia.
B Bureau of Rural Sciences, Barton, ACT 2600, Australia.
C Centre for Mathematical Analysis and its Applications, The Australian National University, Canberra, ACT 0200, Australia.
D Corresponding author. Email: davidl@cres.anu.edu.au
Wildlife Research 32(8) 657-671 https://doi.org/10.1071/WR04069
Submitted: 19 August 2004 Accepted: 17 October 2005 Published: 20 December 2005
Abstract
In this study, we use data drawn from a series of trapping events on four 0.5-ha trapping grids surveyed in the wet eucalypt forests of central Victoria, south-eastern Australia, to identify relationships between capture probabilities and several factors of interest for three species of small mammals that are common throughout the forests of this region: the agile antechinus (Antechinus agilis), the dusky antechinus (Antechinus swainsonii) and the bush rat (Rattus fuscipes). The design of our study – four regular trapping grids – generated spatio-temporal data with binary responses and many covariates. We used powerful and relatively new statistical methodology to deal with the spatio-temporal dependence patterns in the data – analytical problems that are common in trapping data such as these modelled here. Although A. agilis, A. swainsonii and R. fuscipes are among the best studied mammals in Australia, our data analysis produced new perspectives on their probability of being captured. In particular, we quantified how capture probability is affected by trap position within a trapping grid, day of capture in a sequence of trapping days, history of trap occupancy over time by different species and sexes of those species, time of the year or season, and microhabitat attributes. Our insights are discussed in terms of their consequences for trapping protocols that might be applied in the field.
Acknowledgments
This project was completed through the assistance of volunteers from the Earthwatch Institute as well as funding from that organisation and Rio Tinto. Additional support funding for our long-term set of projects in the Victorian wet eucalypt forests (of which this research is part) came from Parks Victoria, the former Department of Natural Resources and Environment (now the Department of Sustainability and Environment), The Myer Foundation, Environment Australia, and Paddy Pallins. DBL is most grateful to (1) Viv Read for providing a copy of his thesis and the experience gained from working with him more than 20 years ago, (2) Chris Dickman for sharing his extraordinary insights and knowledge of Australian small mammal ecology and providing access to a range of key papers, and (3) Craig White for answering questions on computer programs for calculating population sizes from capture–recapture data. Field assistance from Earthwatch volunteers and others who suffered the leeches, snow, rain, close shaves with log trucks and absurdly early mornings included Ryan Incoll, Matthew Pope, Dave Rawlins, Monica Ruibal, Mason Crane and Damian Michael, is gratefully acknowledged. Monica Ruibal kindly assisted with the collection of literature. Karen Viggers assisted with the application of microchip technology for marking small mammals so myriads of toes and ears could be spared.
Banks, P. B. (1998). Responses of Australian bush rats, Rattus fuscipes, to the odour of introduced Vulpes vulpes. Journal of Mammalogy 79, 1260–1264.
Catling, P. C. , and Burt, R. J. (1995). Studies of the ground-dwelling mammals of the eucalypt forests in south-eastern New South Wales – the effect of habitat variables on distribution and abundance. Wildlife Research 22, 271–288.
| Crossref | GoogleScholarGoogle Scholar |
Dickman, C. R. , and Woodside, D. P. (1983). A test of a competition model with reference to three species of small mammals in southeastern Australia. Oecologia 60, 127–134.
| Crossref | GoogleScholarGoogle Scholar |
Knight, E. H. , and Fox, B. J. (2000). Does habitat structure mediate the effects of forest fragmentation and human-induced disturbance on the abundance of Antechinus stuartii? Australian Journal of Zoology 48, 577–595.
| Crossref | GoogleScholarGoogle Scholar |
Lindenmayer, D. B. , Cunningham, R. B. , Donnelly, C. F. , Triggs, B. J. , and Belvedere, M. (1994). The diversity, abundance and microhabitat requirements of terrestrial mammals in contiguous forests and retained linear strips in the montane ash forests of the central highlands of Victoria. Forest Ecology and Management 67, 113–133.
| Crossref | GoogleScholarGoogle Scholar |
Lunney, D. , Cullis, B. , and Eby, P. (1987). Effects of logging and fire on small mammals in Mumbulla State Forest, near Bega, New South Wales. Australian Wildlife Research 14, 163–181.
| Crossref | GoogleScholarGoogle Scholar |
Maitz, W. E. , and Dickman, C. R. (2001). Competition and habitat use in native Australian Rattus: is competition intense, or important? Oecologia 128, 526–538.
| Crossref | GoogleScholarGoogle Scholar |
Norton, T. W. (1987). The effect of trap placement on trapping success of Rattus lutreolus velutinus (Thomas) (Muridae: Rodentia) in north-east Tasmania. Australian Wildlife Research 14, 305–310.
| Crossref | GoogleScholarGoogle Scholar |
Press, A. J. (1987). Comparison of the demography of populations of Rattus fuscipes living in cool temperate rainforests and dry sclerophyll forests. Australian Wildlife Research 14, 45–63.
| Crossref | GoogleScholarGoogle Scholar |
Read, V. T. , Malafant, K. W. , and Myers, K. (1988). A comparison of grid and index-line trapping methods for small mammals. Australian Wildlife Research 15, 673–687.
| Crossref | GoogleScholarGoogle Scholar |
Stewart, A. P. (1979). Trapping success in relation to trap placement with three species of small mammals: Rattus fuscipes, Antechinus swainsonii, and A.stuartii. Australian Wildlife Research 6, 165–172.
| Crossref | GoogleScholarGoogle Scholar |
Tasker, E. M. , and Dickman, C. R. (2002). A review of Elliott trapping methods for small mammals in Australia. Australian Mammalogy 23, 77–87.
Warneke, R. M. (1971). Field study of the bush rat (Rattus fuscipes). Wildlife Contributions, Victoria 14, 1–115.