title: Life history and dynamics of a platypus (Ornithorhynchus anatinus) population: four decades of mark-recapture surveys.
abstract: Knowledge of the life-history and population dynamics of Australia's iconic and evolutionarily distinct platypus (Ornithorhynchus anatinus) remains poor. We marked-recaptured 812 unique platypuses (total 1,622 captures), over four decades (1973-2014) in the Shoalhaven River, Australia. Strong sex-age differences were observed in life-history, including morphology and longevity. Apparent survival of adult females (Φ = 0.76) were higher than adult males (Φ = 0.57), as in juveniles: females Φ = 0.27, males Φ = 0.13. Females were highly likely to remain in the same pool (adult: P = 0.85, juvenile: P = 0.88), while residency rates were lower for males (adult: P = 0.74, juvenile: P = 0.46). We combined survival, movement and life-histories to develop population viability models and test the impact of a range of life-history parameters. While using estimated apparent survival produced unviable populations (mean population growth rate r = -0.23, extinction within 20 years), considering residency rates to adjust survival estimates, indicated more stable populations (r = 0.004, p = 0.04 of 100-year extinction). Further sensitivity analyses highlighted adult female survival and overall success of dispersal as most affecting viability. Findings provide robust life-history and viability estimates for a difficult study species. These could support developing large-scale population dynamics models required to underpin a much needed national risk assessment for the platypus, already declining in parts of its current distribution.
authors.affiliation: Centre for Ecosystem Science, School of Biological, Earth &Environmental Sciences, University of New South Wales, Sydney 2052 NSW, Australia.
authors.forename: Gilad
authors.initials: G
authors.lastname: Bino
authors.affiliation: Centre for Ecosystem Science, School of Biological, Earth &Environmental Sciences, University of New South Wales, Sydney 2052 NSW, Australia.
authors.forename: Tom R
authors.initials: TR
authors.lastname: Grant
authors.affiliation: Centre for Ecosystem Science, School of Biological, Earth &Environmental Sciences, University of New South Wales, Sydney 2052 NSW, Australia.
authors.forename: Richard T
authors.initials: RT
authors.lastname: Kingsford
mesh_terms: D000818:Animals; D001315:Australia; D008018:Life Cycle Stages / Q000502:physiology*; D008136:Longevity / Q000502:physiology*; D010987:Platypus / Q000254:growth & development* / Q000502:physiology*; D011157:Population Dynamics; D012621:Seasons; D011795:Surveys and Questionnaires