Magellanic penguins are keystone species in Patagonian coastal systems

ENTRINGER JR, H.; UDRIZAR SAUTHIER, D. E.; VANTREELS, R.E.T.; ARMANI, A.P.; SRBEK-ARAUJO, A.C.; D'AGOSTINO, R.L; BLANCO, G.

Viña del Mar

Congreso; International Penguin Congress; 2023

IUCN/SSC Penguin Specialist Group

The ecological importance of penguins on land remains unknown. To clarify some of these aspects, we investigated a Magellanic penguin (Spheniscus magellanicus) colony with ~7,000 breeding pairs in central Patagonia, Argentina. From September/2022 to January/2023; we used camera traps (CT) to compare the activity of species within and outside the colony (CT=8; 18,384h, CT=10; 14,928h, respectively). Additionally, we did direct observation of the colony (135h), monitored penguin carcasses (CT=8; 1,050h), collected arthropods (100 individuals) of carcasses, and did forensic analysis to identify species that interacted with penguins. Higher species richness (species=22: including unique aerial predators as brown skua (Catharacta antarctica) and kelp gull (Larus dominicanus) and higher activity were recorded within the colony (records/h=0.140) than in the surroundings (species=11; records/h=0.068). Even when considering the species in common (mostly herbivores as guanaco [Lama guanicoe], hare [Lepus europaeus] and lesser rhea [Rhea pennata]), the general activity remained higher in the colony (records/h=0.105). We recorded six vertebrates that directly interacted with penguins through predation and/or scavenging (brown skua: eggs/carcasses; kelp gull, armadillo [Chaetophractus villosus]: eggs/chicks/carcasses; Geoffroy’s cat [Leopardus geoffroyi]: chicks/adults; vulture [Cathartes aura], caracara [Caracara plancus]: carcasses). The carcasses were also used by arthropods (families=12) for consumption or metamorphosis. Indirect interactions occurred, with kelp gull and dolphin gull (Leucophaeus scoresbii) consuming penguin regurgitation. Thus, penguins may represent a keystone specie in coastal Patagonia, benefiting directly and indirectly marine and terrestrial species, influencing their use of space (possibly due to better food quality and reduced risk of predation) and the functioning of these ecosystems.