Food web structure and species’ role in an oceanic Marine Protected Area in the subantarctic

Abstract

The Marine Protected Area Yaganes (MPAY) was created in response to the great deterioration that has been suffering the ecosystems due to the environmental crisis that is affecting our planet, with the aim to protect key ocean habitats and species. Located at the southern tip of South America, MPAY is home to a wide variety of marine biodiversity and habitats, which makes it of ​​special interest for the conservation of subantarctic environments. For the first time, we described the potential trophic interactions within the MPAY, with emphasis in the pelagic realm. We applied both a network-level and a species-level approach to characterise the structure and complexity properties, aiming to comprehend trophic dynamics and the specific roles of certain species within the food web. In terms of complexity, the MPAY food web consists of 127 species with 658 predator-prey interactions, a density of interactions of 5.18 and a connectance of 0.04. Regarding its structure, around 69% of the species occupied intermediate trophic levels. The Keystone Species Index (KSI), highlighted the importance of some species such as the Patagonian toothfish (Dissostichus eleginoides), the amphipod Themisto gaudichaudii, euphausiids and myctophids, among others, to the structure of the food web.