Dear MARMAM community,

We’d like to let you know about a new publication on Antarctic fur seals in the Proceedings of the Royal Society B: Evidence for an Allee effect in a declining fur seal population. doi: 10.1098/rspb.2020.2882

Abstract: Allee effects play an important role in the dynamics of many populations and can increase the risk of local extinction. However, some authors have questioned the weight of evidence for Allee effects in wild populations. We therefore exploited a natural experiment provided by two adjacent breeding colonies of contrasting density to investigate the potential for Allee effects in an Antarctic fur seal (Please feel free to contact me if you don't have access to the article! Arctocephalus gazella) population that is declining in response to climate change-induced reductions in food availability. Biometric time-series data were collected from 25 pups per colony during two consecutive breeding seasons, the first of which was among the worst on record in terms of breeding female numbers, pup birth weights and foraging trip durations. In previous decades when population densities were higher, pup mortality was consistently negatively density dependent, with rates of trauma and starvation scaling positively with density. However, we found the opposite, with higher pup mortality at low density and the majority of deaths attributable to predation. In parallel, body condition was depressed at low density, particularly in the poor-quality season. Our findings shed light on Allee effects in wild populations and highlight a potential emerging role of predators in the ongoing decline of a pinniped species.

Please feel free to contact me if you don't have access to the article!

Kind regards,

Rebecca Nagel

-- 
Dr. Rebecca Nagel

mail: rebecca.nagel@uni-bielefeld.de
tel.: +49 521 106-2192
room: VHF-203a

Bielefeld University
Department of Animal Behaviour
PO Box 10 01 31
33501 Bielefeld
Germany