Magellanic penguins as a keystone species in Patagonian coastal systems

HILTON ENTRINGER; DANIEL UDRIZAR SAUTHIRE; VANSTREELS, RALPH ERIC THIJL; ANA PAULA ARMANI; ANA C. SRBEK-ARAUJO; ROMINA D'AGOSTINO; GABRIELA S. BLANCO

Congreso; 11th International Penguin Congress; 2023

The ecological importance of penguins on land remains unknown. To address some ofthese aspects, we investigated a Magellanic penguin (Spheniscus magellanicus) colonyat Cabo dos Bahías (~7,000 pairs), central Patagonia, Argentina. We used camera traps(CT), from September/2022 to January/2023, to compare the activity of vertebrateswithin (CT=8; 18,384h) and outside the colony (CT=10; 14,928h). Additionally, weemployed direct observation (135h), monitored penguin carcasses (CT=8; 1,050h),collected arthropods from them, and performed forensic analysis to identify speciesinteracting with penguin carcasses. Species richness [species=22: including aerialpredators as brown skua (Catharacta antarctica) and kelp gull (Larus dominicanus)] andactivity were higher within the colony (records/h=0.140) than in the surroundings(species=11; records/h=0.068). Even when considering the species common to bothsites [mostly herbivores as guanaco (Lama guanicoe), hare (Lepus europaeus) andlesser rhea (Rhea pennata)], the general activity remained higher within the colony(records/h=0.105). Penguins were depredated and/or scavenged by skua (Catharactaantarctica; eggs/carcasses), kelp gull (Larus dominicanus; eggs/chicks/carcasses),armadillo (Chaetophractus villosus; eggs/chicks/carcasses), Geoffroy’s cat (Leopardusgeoffroyi; chicks/adults), vulture (Cathartes aura; carcasses), and caracara (Caracaraplancus; carcasses). The carcasses were also used by arthropods (families=12) forconsumption and/or metamorphosis. Additionally, kelp gull and dolphin gull(Leucophaeus scoresbii) interacted indirectly with penguins by consuming adults’regurgitates. Magellanic penguins may be a keystone species in coastal Patagonia; asthey are an important food resource that influence the spatial use of marine andterrestrial species, benefiting the functioning of the ecosystems where they breed.