Biodiversity as insurance: from concept to measurement and application

Michel Loreau, Matthieu Barbier, Elise Filotas, Dominique Gravel, Forest Isbell, Steve J. Miller, Jose M. Montoya, Shaopeng Wang, Raphaël Aussenac, Rachel Germain, Patrick L. Thompson, Andrew Gonzalez, Laura E. Dee

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Biological insurance theory predicts that, in a variable environment, aggregate ecosystem properties will vary less in more diverse communities because declines in the performance or abundance of some species or phenotypes will be offset, at least partly, by smoother declines or increases in others. During the past two decades, ecology has accumulated strong evidence for the stabilising effect of biodiversity on ecosystem functioning. As biological insurance is reaching the stage of a mature theory, it is critical to revisit and clarify its conceptual foundations to guide future developments, applications and measurements. In this review, we first clarify the connections between the insurance and portfolio concepts that have been used in ecology and the economic concepts that inspired them. Doing so points to gaps and mismatches between ecology and economics that could be filled profitably by new theoretical developments and new management applications. Second, we discuss some fundamental issues in biological insurance theory that have remained unnoticed so far and that emerge from some of its recent applications. In particular, we draw a clear distinction between the two effects embedded in biological insurance theory, i.e. the effects of biodiversity on the mean and variability of ecosystem properties. This distinction allows explicit consideration of trade-offs between the mean and stability of ecosystem processes and services. We also review applications of biological insurance theory in ecosystem management. Finally, we provide a synthetic conceptual framework that unifies the various approaches across disciplines, and we suggest new ways in which biological insurance theory could be extended to address new issues in ecology and ecosystem management. Exciting future challenges include linking the effects of biodiversity on ecosystem functioning and stability, incorporating multiple functions and feedbacks, developing new approaches to partition biodiversity effects across scales, extending biological insurance theory to complex interaction networks, and developing new applications to biodiversity and ecosystem management.

Original languageEnglish (US)
Pages (from-to)2333-2354
Number of pages22
JournalBiological Reviews
Issue number5
StatePublished - Oct 2021

Bibliographical note

Funding Information:
M.L., M.B. and J.M.M. were supported by the TULIP Laboratory of Excellence (ANR‐10‐LABX‐41). M.L. and M.B. were also supported by the BIOSTASES Advanced Grant and J.M.M. by the FRAGCLIM Consolidator Grant, both of which were funded by the European Research Council under the European Union's Horizon 2020 research and innovation programme (grant agreements No 666971 and 726176). A.G. was supported by the Liber Ero Chair in Biodiversity Conservation. This paper arose from a joint working group supported by the Quebec Centre for Biodiversity Science (working group #12) and the Centre for Biodiversity Theory and Modelling (Moulis, France).

Publisher Copyright:
© 2021 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.


  • biodiversity
  • ecosystems
  • insurance
  • management
  • portfolio
  • stability
  • theory


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