New publication from Eisenhauer et al. in npj Biodiversity: Reply: Functional similarity is more appropriate than functional redundancy

Replying to Felícia M. Fischer and Francesco de Bello npj Biodiversity (2023)

In our Comment, we outlined that the term functional redundancy (1) may have been overused from an ecological perspective and (2) can be dangerous and misleading in scientific communication. As a constructive way forward, we proposed to use the concept of “functional similarity” with regard to specific ecosystem functions to better highlight the unique contributions of all coexisting species to ecosystem functioning (Fig. 1). Moreover, we argued that functional similarity better describes gradients in niche overlap while having a less negative connotation. We were motivated to propose this change in terminology because of the intense public discourse on biodiversity-related topics and the potential of misinterpretation that may be caused by the mostly negative connotation that is associated with redundancy.

Fig. 1: Conceptual figure displaying hypothetical species A–E in two-dimensional trait space.
Species that strongly overlap with respect to one trait, such as plant size gradient (e.g., plant height or rooting depth), may be dissimilar with respect to a second trait, such as root collaboration gradient14. In this simple example, only two traits are displayed for simplicity, while ecological niches are highly multidimensional. Describing species as functionally similar is more appropriate than describing them as functionally redundant.


Eisenhauer, N., J. Hines, and M. C. Rillig. 2023. Reply: Functional similarity is more appropriate than functional redundancy. npj Biodiversity 2:1–2.