Isotope data

Keystone species identification should consider species uniqueness alongside centrality. Clarifying the correlation between species centrality and uniqueness, or whether central species exhibit positional redundancy in food webs, can enhance the understanding of mechanisms stabilizing food webs. However, the findings from analyses utilizing different measures of uniqueness are contentious. In this study, the eutrophic lake Zhangze Lake is taken as the research object, and innovatively combines stable isotope techniques with the theory of uniqueness to assess species uniqueness under both traditional and improved methods, using the contribution of food source to consumers as a weighting factor. Additionally, we examined the relationship between different uniqueness indices and centrality to ascertain whether centrality species are functionally redundant, and we analyzed how thresholds and weak interaction considerations (i.e., improved uniqueness index) influence the results.