The complex network of trophic interactions in a sub-Antarctic oceanic Marine Protected Area

MARINA, TI; SCHLOSS, IR; LOVRICH, GA; BOY, CC; BRUNO, DO; CAPITANIO, FL; DELPIANI, SM; DÍAZ DE ASTARLOA, JM; FRAYSSE, C; GARCÍA ALONSO, VA; RAYA REY, A; SCHEJTER, L; SPINELLI, ML; TATIÁN, M; URTEAGA, D; RICCIALDELLI, L

MARINE ECOLOGY PROGRESS SERIES

INTER-RESEARCH

Lugar: Oldendorf/Luhe; Año: 2024

0171-8630

The total area of the world ocean designated under marine protection has increased recently. Most Marine Protected Areas (MPAs) target vulnerable, keystone, charismatic and/or endemic species. In the sub-Antarctic, ocean protection is associated to oceanic islands, except for MPAs Namuncurá - Burdwood Bank I and II (MPA N-BB, ~53º–55ºS and ~56º– 62ºW), which are associated to a submarine plateau and its southern adjacent deep slope, respectively. Here, we present the first analysis of the network of predator-prey interactions for the MPA N-BB. We applied a network approach to characterise the complexity and structure of the food web, and identify the species´ role in such a framework. The MPA N-BB food web consisted of 1788 interactions and 379 species, with a connectance of 0.01. Almost half of the consumers were omnivores (0.48), and the network displayed a small-world pattern. These suggest that the ecosystem might be vulnerable to perturbations targeting highly connected species, although other properties might provide resilience and resistance, resulting in a rearranged structure that preserves its original functions. Several species arose as important in terms of different aspects of trophic structure and functioning, and response to perturbations. Generalist species, mainly fishes, play a crucial role in the ecosystem´s benthopelagic coupling and should be considered as relevant energy transfers for the ecosystem. We argue that the diversity of species, including both the benthic and pelagic habitats, is responsible for securing the connectivity within the food web against perturbations, therefore contributing to the structure and stability of the ecosystem.