Seasonal sea ice fluctuations influence population dynamics across the West Antarctic Peninsula (wAP), a region that has experienced some of the most rapid sea ice declines anywhere along the continent. In the northern region, the ice-obligate Adélie penguins (P. adeliae) have declined by approximately 90% over the last several decades whereas southern colonies have not. Sea-ice and snow are important factors for Adélie penguin population dynamics and can influence breeding habitat, breeding success, and fledging weight. This study investigates the disturbances of storms across temporal and spatial scales as a driver of the declining Adélie penguin population. Potential impacts from storms are investigated both indirectly (sea ice and snow) and directly (breeding success and fledging weight). Understanding the drivers of population decline will help predict how southern colonies may respond as the ecosystem shifts from polar to subpolar. To date, this study examined the temporal relationship of sea-ice indices (advance, retreat, and duration) with storm intensity and frequency from 1979 to 2016 along the wAP. Storm frequency showed a statistically significant increase over time for the austral Fall season. Sea-ice advance is shifting later in many areas, predominantly coastal zones. These coastal zones experience a delayed advancement when the mean storm intensity is increased. Future work incorporating the penguin metrics will use mixed models to identify the physical drivers influencing Adélie breeding success and fledging weight.

Primary Presenter: Mary Stack, University of Virginia (mary.elizabeth.stack@gmail.com)

Authors:

Mary Stack, University of Virginia  (nyd9rw@virginia.edu)

Kevin Grise, University of Virginia  (kmg3r@virginia.edu)

Sharon Stammerjohn, Institute of Arctic and Alpine Research, University of Colorado Boulder  (sharon.stammerjohn@colorado.edu)

Megan Cimino, University of California, Santa Cruz  (mecimino@ucsc.edu)

Scott Doney, University of Virginia  (scd5c@virginia.edu)