![]() ![]() Mounting evidence of recent local platypus population declines and extinctions highlight a species facing considerable risks 8, 9, 10, 11, 12. It lives and breeds mainly in permanent reaches of streams but also in some lakes and wetlands, from which juveniles disperse, following each breeding season. Genetic analyses indicate three natural sub-populations: northern Queensland, Tasmania/King Island, and the rest of mainland Australia 5, 6, 7. Except for in the far north, this endemic species occurs along the margins of the eastern Australian mainland and in Tasmania and adjacent King Island, with a small introduced population on Kangaroo Island. It is one of the most evolutionarily distinct mammals on Earth, belonging to a subclass separated from all other living mammals 2, 3, 4, making it of exceptional scientific value and an irreplaceable component of Australian and global biodiversity. The platypus ( Ornithorhynchus anatinus) is one of only five extant species of egg-laying mammals and the only species within the family Ornithorhynchidae 1. 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. ![]() Findings provide robust life-history and viability estimates for a difficult study species. ![]() Further sensitivity analyses highlighted adult female survival and overall success of dispersal as most affecting viability. 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). We combined survival, movement and life-histories to develop population viability models and test the impact of a range of life-history parameters. 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). 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. Strong sex-age differences were observed in life-history, including morphology and longevity. We marked-recaptured 812 unique platypuses (total 1,622 captures), over four decades (1973–2014) in the Shoalhaven River, Australia. Knowledge of the life-history and population dynamics of Australia’s iconic and evolutionarily distinct platypus ( Ornithorhynchus anatinus) remains poor. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |