The Food Web of Potter Cove (Antarctica): complexity, structure and function

• Language: unknown
• Published: 2018
• Subjects: Antarctica; Degree distribution; Ecological networks; Marine ecosystem; Structure; amphipod; benthic environment; biodiversity; carbon flux; complexity; demersal fish; ecosystem function; energy flow; food web; functional group; network analysis; pelagic environment; specialization; trophic cascade; trophic interaction; trophic structure; Antarctic Peninsula; King George Island; Potter Cove; South Shetland Islands; West Antarctica; Amphipoda; Antarctic; Antarc*
• Online Access: https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02727714_v200_n_p141_Marina; https://hdl.handle.net/20.500.12110/paper_02727714_v200_n_p141_Marina

Knowledge of the food web structure and complexity are central to better understand ecosystem functioning. A food-web approach includes both species and energy flows among them, providing a natural framework for characterizing species’ ecological roles and the mechanisms through which biodiversity influences ecosystem dynamics. Here we present for the first time a high-resolution food web for a marine ecosystem at Potter Cove (northern Antarctic Peninsula). Eleven food web properties were analyzed in order to document network complexity, structure and topology. We found a low linkage density (3.4), connectance (0.04) and omnivory percentage (45), as well as a short path length (1.8) and a low clustering coefficient (0.08). Furthermore, relating the structure of the food web to its dynamics, an exponential degree distribution (in- and out-links) was found. This suggests that the Potter Cove food web may be vulnerable if the most connected species became locally extinct. For two of the three more connected functional groups, competition overlap graphs imply high trophic interaction between demersal fish and niche specialization according to feeding strategies in amphipods. On the other hand, the prey overlap graph shows also that multiple energy pathways of carbon flux exist across benthic and pelagic habitats in the Potter Cove ecosystem. Although alternative food sources might add robustness to the web, network properties (low linkage density, connectance and omnivory) suggest fragility and potential trophic cascade effects. © 2017 Elsevier Ltd