[MARMAM] New publication: Increase in trophic segregation in response to warming ocean conditions in Peruvian Humboldt Current System

Susana Cardenas scardenas at csa-upch.org
Tue Aug 16 17:44:58 PDT 2022


Dear MARMAM colleagues,

My co-authors and I are pleased to share our new publication "Sympatric
otariids increase trophic segregation in response to warming ocean
conditions in Peruvian Humboldt Current System" published in PloS One. PDF
is freely available using the link below.

Cárdenas-Alayza S, Adkesson MJ, Edwards MR, Hirons AC, Gutiérrez D,
Tremblay Y, Franco-Trecu, V (2022) Sympatric otariids increase trophic
segregation in response to warming ocean conditions in Peruvian Humboldt
Current System. PLoS ONE 17(8): e0272348.
https://doi.org/10.1371/journal.pone.0272348


ABSTRACT: Determining trophic habits of predator communities is essential
to measure interspecific interactions and response to environmental
fluctuations. South American fur seals, Arctocephalus australis (SAFS) and
sea lions Otaria byronia (SASL), coexist along the coasts of Peru.
Recently, ocean warming events (2014–2017) that can decrease and impoverish
prey biomass have occurred in the Peruvian Humboldt Current System. In this
context, our aim was to assess the effect of warming events on long-term
inter- and intra-specific niche segregation. We collected whiskers from
SAFS (55 females and 21 males) and SASL (14 females and 22 males) in Punta
San Juan, Peru. We used δ13C and δ15N values serially archived in otariid
whiskers to construct a monthly time series for 2005–2019. From the same
period we used sea level anomaly records to determine shifts in the
predominant oceanographic conditions using a change point analysis. Ellipse
areas (SIBER) estimated niche width of species-sex groups and their
overlap. We detected a shift in the environmental conditions marking two
distinct periods (P1: January 2005—October 2013; P2: November 2013—December
2019). Reduction in δ15N in all groups during P2 suggests impoverished
baseline values with bottom-up effects, a shift towards consuming lower
trophic level prey, or both. Reduced overlap between all groups in P2 lends
support of a more redundant assemblage during the colder P1 to a more
trophically segregated assemblage during warmer P2. SASL females show the
largest variation in response to the warming scenario (P2), reducing both
ellipse area and δ15N mean values. Plasticity to adapt to changing
environments and feeding on a more available food source without fishing
pressure can be more advantageous for female SASL, albeit temporary trophic
bottom-up effects. This helps explain larger population size of SASL in
Peru, in contrast to the smaller and declining SAFS population.


Please, do not hesitate to contact me for any questions.

Best to all,
-- 
Susana Cárdenas Alayza, MSc, PhD
Directora
Programa Punta San Juan
Centro para la Sostenibilidad Ambiental
Universidad Peruana Cayetano Heredia
cel. +51 999931218
Email: scardenas at csa-upch.org
http://www.puntasanjuan.org/
¡Síguenos en Facebook! <https://www.facebook.com/ProgramaPSJ/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.uvic.ca/pipermail/marmam/attachments/20220816/4a93eac0/attachment.html>


More information about the MARMAM mailing list