Landfast ice: a major driver of reproductive success in a polar seabird

In a fast-changing world, polar ecosystems are threatened by climate variability. Understanding the roles of fine-scale processes, and linear and nonlinear effects of climate factors on the demography of polar species is crucial for anticipating the future state of these fragile ecosystems. While the effects of sea ice on polar marine top predators are increasingly being studied, little is known about the impacts of landfast ice (LFI) on this species community. Based on a unique 39-year time series of satellite imagery and in situ meteorological conditions and on the world's longest dataset of emperor penguin (Aptenodytes forsteri) breeding parameters, westudied the effects of fine-scale variability of LFI and weather conditions onthisspecies' reproductive success. We found that longer distances to the LFI edge (i.e. foraging areas) negatively affected the overall breeding success but also the fledging success. Climate window analyses suggested that chick mortality was particularly sensitive to LFI variability between August and November. Snowfall in May also affected hatching success. Given the sensitivity of LFI to storms and changes in wind direction, important future repercussions on the breeding habitat of emperor penguins are to be expected in the context of climate change.

Automated summary

Based on a unique 39-year dataset, this study found that the reproduction success of emperor penguins is influenced by the fine-scale variability of landfast ice (LFI) and weather conditions. Longer distances to the LFI edge negatively affected breeding success, while climate factors such as snowfall in May and LFI variability between August and November also played a significant role in chick mortality and hatching success. Future repercussions on the breeding habitat of emperor penguins are expected due to the sensitivity of LFI to storms and changes in wind direction in the context of climate change.