The response of trophic interaction networks to multiple stressors in a marine latitudinal gradient of the Southern Hemisphere

Ecological networks offer valuable insights into community structure, key species identification, and ecosystem management for biodiversity conservation. Understanding how these networks react to environmental and anthropogenic stressors, especially along geographical gradients, is of increasing interest. This review presents a pioneering analysis of stressor responses in marine food webs from the southwest Atlantic to the Antarctic (45 - 78ºS), encompassing areas such as San Jorge Gulf, Beagle Channel, Burdwood Bank, Scotia Sea, Potter Cove, and the Weddell Sea in Antarctica. Our objectives are to: 1) describe the structure of marine food webs along this axis using a network approach; 2) identify predominant environmental and anthropogenic stressors affecting each ecosystem; and 3) summarize observed food web changes and hypothesize on stressor impacts. Our collaborative team, comprising regional experts and global authorities on high-latitude marine food webs and stressor effects, ensures a comprehensive and credible literature review. We assessed the effects of stressors primarily at the species level, with notable exceptions like fisheries in San Jorge Gulf. Hypotheses for each study area were formulated considering: a) stressors; b) impacted parameters; c) node-level species properties; and d) network-level food web properties. Global warming emerges as the most common stressor across the gradient, except in the Beagle Channel and Burdwood Bank, where alien species introduction and fisheries are more influential, respectively. We offer specific hypotheses on how warming may affect food webs. Our findings highlight the benefits of a network approach in understanding and predicting stressor effects in Southern Hemisphere marine ecosystems. This approach provides a holistic understanding of ecological networks, enhances our ability to identify key species and interactions, and offers insights for ecosystem management and conservation in the face of various stressors.