Life history and demographics of an island possum
Joanne L. IsaacSchool of Tropical Biology, James Cook University, Townsville, Qld 4811, Australia. Email: joanne.isaac@jcu.edu.au
Australian Journal of Zoology 53(3) 195-203 https://doi.org/10.1071/ZO05018
Submitted: 18 April 2005 Accepted: 26 April 2005 Published: 16 June 2005
Abstract
Knowledge of life history and demography is essential for effective management of target species. Here, I describe life history and demographic traits of the common brushtail possum (Trichosurus vulpecula) on Magnetic Island, north Queensland. Data were collected during monthly live-trapping sessions over three years (2001–2004). Density was ~100% higher than reported in most Australian populations, at 5 possums per hectare; losses from the population were more than compensated for by births and immigration. Age-specific survival differed between the sexes: male survival declined earlier and faster than female survival. Males were significantly heavier than females as adults and sexual dimorphism appears to arise through a faster growth rate in males following weaning. Age at maturity in females varied from 1 to 3 years; 61% of females produced their first young at age 2. Males became sexually mature at age 3. Breeding was seasonal, with >50% births occurring in April–May; a smaller birth peak in spring was due to some females producing a second young after they had successfully weaned a first. The Magnetic Island possum population appears to be more similar to New Zealand populations, in terms of their life history and demographics, than to other previously studied mainland Australian populations.
Acknowledgments
I thank Chris Johnson and Andrew Krockenberger for supervising all aspects of the project; Brett Goodman, Jane Degabriel and Euan Ritchie for commenting on previous drafts; Euan Ritchie, Tanya Cornish, Nick Mann and Bryan Leighton for help in the field. James Cook University, the Australian Research Council, the Ecological Society of Australia and the Joyce Vickery Scientific Fund provided financial support. This research was carried out under Scientific Purposes Permits N0/000999/99/SAA and WISP01170503 issued by Queensland Parks and Wildlife Service, and Ethics Permit No. A822 issued by James Cook University.
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