Dear MARMAM Colleagues My co-authors and I would like to share our recent publication:
Cárdenas‐Alayza, S., Torres, D. A., Gutiérrez, D., & Tremblay, Y. (2022). Resource partitioning as a mechanism for trophic segregation in sympatric otariids from the productive upwelling Peruvian Humboldt Current System. Austral Ecology: 47(4):775-790. doi.org/10.1111/aec.13158 Abstract Resource partitioning can contribute to species coexistence by reducing interspecific competition. To understand whether resource partitioning contributes towards sympatric populations of two otariids in Peru’s dynamic Humboldt Current System (HCS), we compared seasonal diet composition of South American fur seals (SAFS, Arctocephalus australis) and South American sea lions (SASL, Otaria byronia) over 15 seasons between 2015 and 2018 to determine whether there is a detectable mechanism for resource partitioning at population level. Diet composition was estimated from identification of hard remains of prey items obtained from 3325 scats collected from rookeries at Punta San Juan, Peru. SAFS diet is primarily composed of Peruvian anchovy (42.8%) and cephalopods (34.7%); with smaller components of myctophids (7.4%), red squat lobsters (5%), and 11 other fish species. SASL diet is mainly composed of red squat lobster (69.9%) and Peruvian anchovy (19.1%); with smaller amounts of cephalopods (4.7%), silversides (4.6%), and five other fish species. In this study, both predators were classified as specialists and interspecific trophic segregation was found in 13 of the 15 seasons sampled. Trophic overlap was detected in the austral summer and fall of 2015 during an extraordinary El Niño event, in which both otariids consumed similar proportions of Peruvian anchovy (55% SAFS, 48.6% SASL), cephalopods (21.7% SAFS, 13.6% SASL) and red squat lobsters (9% SAFS, 2% SASL). In conclusion, the analysis demonstrates resource partitioning based on the abundance of primary prey items consumed by two otariid species and helps explain trophic segregation in otariids of HCS. Furthermore, results show that climatic changes can trigger abrupt reduction in prey items and exacerbate interspecific competition. *** Do not hesitate to email me if you are interested in the PDF. Best, -- Susana Cárdenas Alayza, MSc., PhD. Directora Programa Punta San Juan Centro para la Sostenibilidad Ambiental Universidad Peruana Cayetano Heredia http://www.puntasanjuan.org/ ¡Síguenos en Facebook! <https://www.facebook.com/ProgramaPSJ/> https://www.researchgate.net/profile/Susana-Cardenas
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