Green vs brown food web: Effects of habitat type on multidimensional stability proxies for a highly-resolved Antarctic food web

Abstract

Food web analyses are powerful tools to understand the structure, dynamics and stability of communities. Potter Cove (25 de Mayo/King George Island) is one of the most biodiverse and studied fjords on the West Antarctic Peninsula (WAP), where climate change is affecting benthic and pelagic communities. This fjord ecosystem presents a considerable degree of environmental and species distribution heterogeneity across space: the outer portion of the cove is dominated by hard bottoms meanwhile the inner portion is dominated by soft bottoms. In this work, we have incorporated habitat type to a highly-resolved Antarctic food web, and evaluated its effects on different network metrics and proxies for various dimensions of stability. We considered a multidimensional perspective and employed simulation techniques to encompass variability. Our results showed that the incorporation of habitat type to Potter Cove food web analysis led to two different functional types of networks segregated on space: a green food web (in the outer cove) and a brown food web (in the inner cove). The green and the brown food webs showed significant differences in network structure and in some proxies for multidimensional stability (i.e. quasi sign-stability and omnivory), suggesting that these two food webs have different resilience to perturbations. However, there were no changes in network robustness when in silico experiments were performed. We conclude that habitat type plays a significant role in the structure and stability of Antarctic food webs, and should be taken into account to design effective conservation strategies.