Recent studies overestimate colonization and extinction events for Adelie Penguin breeding colonies

• Published in: The Auk
• Main Authors: Southwell, Colin, Emmerson, Louise, Takahashi, Akinori, Kato, Akiko, Barbraud, Christophe, Delord, Karine, Weimerskirch, Henri
• Other Authors: Australian Antarctic Division (AAD), Australian Government, Department of the Environment and Energy, National Insitute of Polar Research, National Institute of Polar Research Tokyo (NiPR), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: Antarctica; high-resolution satellite imagery; historical data; metapopulation dynamics; occupancy; [SDE]Environmental Sciences; East Antarctica; Guano; Adelie penguin; Antarc*; Pygoscelis adeliae
• Online Access: https://hal.science/hal-01502843; https://doi.org/10.1642/AUK-16-125.1

International audience Modeling metapopulation dynamics is potentially a useful and powerful tool for ecologists and conservationbiologists. However, the key processes driving metapopulation dynamics are colonization and extinction events, whichare notoriously difficult to study. A recent global assessment of Adelie Penguin (Pygoscelis adeliae) breedingpopulations reported multiple potential colonization and extinction events from occupancy observations using recenthigh-resolution satellite imagery and examination of historical occupancy literature, but emphasized that the eventsshould be confirmed with direct observations. We evaluated these conclusions by developing a comprehensivedatabase of direct observations of Adelie Penguin breeding site occupancy across East Antarctica. The databaseallowed 16 of 19 proposed colonization and extinction events in this region to be evaluated using direct observationsthat were concurrent in space and time (same breeding season) with observations from satellite imagery. Weconcluded that none of the 16 proposed colonization and extinction events had occurred. One true extinction eventmay have been correctly identified from satellite imagery, but a conclusive evaluation was not possible because thedirect and satellite observations were not concurrent in time. The evaluation identified several sources of error inobservations from satellite imagery, including errors of omission through failure to detect small colonies and errors ofcommission through misidentification of other biological and physical features as Adelie Penguin guano. Theoccupancy database corrected issues of poor precision and accuracy in locations of historical occupancy data. Ourresults improve understanding of key parameters for Adelie Penguin metapopulation dynamics and facilitateimproved interpretation of satellite imagery in the future.