GEP at Boulder University

Meritxell Genovart and Daniel Oro are visiting the University of Boulder (Colorado, USA) for three months.Their collaboration with Prof D. Doak will certainly bring exciting results in the field of population dynamics. We will keep you posted.

Master Project at the GEP

Nikola Matovic joined the GEP for 6 months to carry out his MSc project for the "European MSc in Marine Environment and Resources" . He will develop his research titled "Modelling the relationship between Storm petrel survival and environmental factors" under the supervision of Dr. A. Sanz-Aguilar. Welcome Nikola!
 

New publication on Sea Ice and Penguins

Ballerini, T., Tavecchia, G., Pezzo, F., Jenouvrier, S. and Olastroni, S. 2015 Predicting responses of the Adélie penguin population of Edmonson Point to future sea ice changes in the Ross Sea. Frontiers in Ecology and Evolution. doi: 10.3389/fevo.2015.00008 

Atmosphere-Ocean General Circulation Models (AOGCMs) predict changes in the sea ice environment and in atmospheric precipitations over larger areas of Antarctica. These changes are expected to affect the population dynamics of seabirds and marine mammals, but the extent of this influence is not clear. We investigated the future population trajectories of the colony of Adélie penguins at Edmonson Point, in the Ross Sea, from 2010 to 2100. To do so, we incorporated the relationship between sea ice and demographic parameters of the studied colony into a matrix population model. Specifically, we used sea ice projections from AOGCMs and a proxy for snowfall precipitation. Simulations of population persistence under future climate change scenarios showed that a reduction in sea ice extent (SIE) and an increase in precipitation events during the breeding season will drive the population to extinction. However, the population growth rate estimated by the model was lower than the population growth rate observed during the last decades, suggesting that recruits from other colonies maintain the observed population dynamics at Edmonson Point. This local “rescue” effect is consistent with a metapopulation dynamic for Adélie penguins in the Ross Sea, in which neighboring colonies might exhibit contrasting population trends and different density-dependent effects. In the hypothesis that connectivity with larger source colonies or that local recruitment would decrease, the sink colony at Edmonson Point is predicted to disappear.

Read also a newspaper note at "Repubblica.it"

New publication on seabirds !

Steigerwald, E., Igual, J.-M., Payo-Payo, A., and Tavecchia G. Effects of decreased anthropogenic food availability on an opportunistic gull: evidence for a size-mediated response in breeding females Ibis in press

Photo: G. Tavecchia

Some opportunistic vertebrates exploit, and may largely rely upon, food generated by human activities. Better understanding the influence of this additional anthropogenic food on species’ ecology would inform sustainable waste management. In the Balearic Archipelago of Spain, closure of an open-air landfill site provided an experimental setting to measure the effect of removing anthropogenic food on the average body mass, breeding parameters and body condition of opportunistic Yellow-legged Gulls Larus michahellis. After landfill closure there was a significant decline in the average body mass of breeding females and males (-10.4% and -7.8%, respectively), in average egg volume (-4.8%), and a shift in the modal clutch size from 3 to 2 eggs. Body condition decreased after landfill closure in both sexes. In breeding females, the drop in body weight was greater for birds with a low body size index. The differential response to a reduction of anthropogenic food between small and large birds suggests that food of anthropogenic origin contributes to temper the effects of natural selection, making the long-term demographic effects of changes in food supply difficult to predict.