Climate-related habitat suitability of the Antarctic shag (Leucocarbo bransfieldensis) along the Antarctic Peninsula under future climate scenarios

Abstract Climate change is rapidly altering Antarctic coastal ecosystems, potentially affecting the distribution of endemic seabirds. In this study, we evaluated the relationships between climate-related environmental variables and the breeding distribution of the Antarctic shag ( Leucocarbo bransfieldensis ) along the Antarctic Peninsula and explored how future environmental change may affect habitat suitability by the end of the 21st century (2090–2100). Habitat suitability models were developed using the MaxEnt algorithm based on occurrence records associated with the species’ breeding distribution and environmental predictors obtained from Bio-ORACLE v2.2. Future projections were generated under two greenhouse gas emission scenarios (RCP4.5 and RCP8.5). Mean ice thickness, minimum temperature, and salinity emerged as the most influential predictors associated with the species’ breeding distribution. Model projections suggested moderate increases in environmentally suitable areas under both RCP4.5 (8.8%) and RCP8.5 (8.7%), accompanied by a spatial redistribution toward colder coastal sectors of the Antarctic Peninsula. However, projected suitability patterns should be interpreted cautiously, as the models represent associations with environmental conditions rather than direct predictions of future occupancy. Factors such as breeding-site availability, dispersal limitations, and biotic interactions may constrain the occupation of newly suitable areas. Our results suggest that climate-related changes in sea ice dynamics and nearshore environmental conditions may alter environmental suitability patterns associated with the species’ breeding distribution.