Advances in remote sensing of emperor penguins: first multi-year time series documenting trends in the global population

Like many polar animals, emperor penguin populations are challenging to monitor because of the species' life history and remoteness. Consequently, it has been difficult to establish its global status, a subject important to resolve as polar environments change. To advance our understanding of emperor penguins, we combined remote sensing, validation surveys and using Bayesian modelling, we estimated a comprehensive population trajectory over a recent 10-year period, encompassing the entirety of the species' range. Reported as indices of abundance, our study indicates with 81% probability that there were fewer adult emperor penguins in 2018 than in 2009, with a posterior median decrease of 9.6% (95% credible interval (CI) -26.4% to +9.4%). The global population trend was -1.3% per year over this period (95% CI = -3.3% to +1.0%) and declines probably occurred in four of eight fast ice regions, irrespective of habitat conditions. Thus far, explanations have yet to be identified regarding trends, especially as we observed an apparent population uptick toward the end of time series. Our work potentially establishes a framework for monitoring other Antarctic coastal species detectable by satellite, while promoting a need for research to better understand factors driving biotic changes in the Southern Ocean ecosystem.

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, we studied the effects of fine-scale variability of LFI and weather conditions on this species' 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.

Blood flow compared in benign melanocytic naevi, malignant melanomas and basal cell carcinomas

Histologically, increasing malignancy is reflected by increased tumour vascularization. We therefore assessed whether laser Doppler perfusion imaging might allow differentiation between different types of skin tumour. The perfusion patterns of 27 melanocytic naevi, 16 basal cell carcinomas and six malignant melanomas were examined with a laser Doppler perfusion imager before excision for precise diagnosis. Malignant melanomas were significantly more perfused than basal cell carcinomas and tended also to be more so than melanocytic naevi. Further, for the first time, the perfusion pattern of the entire tumour area was visualized two-dimensionally; it was higher in the centre of the tumours than at the periphery for malignant melanomas and melanocytic naevi but was the same throughout for basal cell carcinomas. Laser Doppler perfusion imaging can thus provide information to assist in the differential diagnosis of skin tumours. In addition, with increases in resolution of the technique such data may well become steadily more useful in the future.