Abstract

Species loss is a non-random reality that worldwide ecosystems are living and the understanding of their consequences is a major challenge in ecology. In natural ecosystems, species are part of a complex network of ecological relationships. Hence, the loss of one species could trigger secondary extinction cascades difficult to predict. Therefore, it is a necessity to understand how ecological communities respond to different extinction scenario. Simulating sequential species’ extinctions within trophic networks, based on topological (without dynamic) and/or dynamical approaches, early studies have mostly found that the whole system is most vulnerable to the loss of highly connected species. These studies introduced sequential species’ extinctions based on: (i) different node traits; (ii) actual extinctions observed in communities. However, rarely used criteria, based on eigenvector-based algorithms, allowed detecting the most detrimental extinction path for the whole community. Nevertheless, this method has only been tested in topological approaches, while a dynamical approach is still lacking. We assessed the performance of the eigenvector-based algorithm, analyzing and comparing the robustness of a comprehensive Chilean marine food-web. We did it using topological and dynamical approaches, in which we deleted species from the most to the least important based on the following criteria: nodes connectivity, eigenvector-based algorithm, and commercial importance. Both approaches showed that the community was least robust to the eigenvector-based deletion sequence. Likewise, in all deletion sequences, the topological approach overestimated the trophic network robustness. The most important species to maintain the network robustness were the ones that occupied the lowest trophic levels, with high vulnerability and small body-mass. We highlighted the importance of use eigenvector-based algorithm to identify the fastest route of collapse. Our results serve as a reminder that species with small body-mass should not be forgotten, especially those in which their abundance is vulnerable to environmental conditions.